Yi Wye i 7 We i ————= —— : 2.21 a''a ‘aia’ a @ .2'818°8.0. 074 DAD. B.S OB AA Aa A eae > ee rey aR he FN > dz Sey 6 ~ a ioe i a es / é iy 4 = 2 = a is a : ‘ee 3 Sasexeteite: a 4 iB: . AZ no & igen CP ESM OO 72 ap — ee ~ re ME see \ OTST hes Pan ( nny Dah rt AM ented 4 Vy RATE AW RAN {ys a i ty ghey 4 PN ECHR Fase ia : MRE ANY | RNS JOURNAL OF THE ROYAL MICROSCOPICAL SOCIETY; CONTAINING ITS TRANSACTIONS AND PROCEEDINGS, AND A SUMMARY OF CURRENT RESEARCHES RELATING TO ZOOLOGY AND BOTAN YD (principally Invertebrata and Cryptogamia), MICROSCOPYW, Sc. LIBRARY NEW YORK Ldited by BOTANICAL GARDEN FRANK CRISP, LL.B. B.A, One of the Secretaries of the Society and a Vice-President and Treasurer of the Linnean Society of London ; WITH THE ASSISTANCE OF THE PUBLICATION COMMITTEE AND A. W. BENNETT, M.A., B.Sc., F, JEFFREY BELL, M.A, Lecturer on Botany at St. Thomas’s Hospital, Professor of Comparative Anatomy in King’s College 8. O. RIDLEY, M.A., of the British Museum, asp JOHN MAYALL, Jon., FELLOWS OF THE SOCIETY, ser. fl—VOL. lls PART 2. PUBLISHED FOR THE SOCIETY BY WILLIAMS & NORGATE, LONDON AND EDINBURGH. ESS 2:, The Journal 1s issued on the second Wednesday of February, April, June, August, October, and December. Phy ; $ Bic Ser. II. : To Non-Fellows { Vol. 11. Part 4.} AUGUST, 1882, |" Price 48. JOURNAL OF THE | MICROSCOPICAL SOCIETY; CONTAINING ITS TRANSACTIONS AND PROCEEDINGS, AND A SUMMARY OF CURRENT RESEARCHES RELATING TO ZOOLOGY AND BOTAN YT (principally Invertebrata and Cryptogamia), MICROSCOPY, &c- a —, Edited by FRANK CRISP, LL.B., B.A., One of the Secretaries of the Society and @ Vice-President and Treasurer of the Linnean Society of London ; WITH THE ASSISTANCE OF THE PUBLICATION COMMITTEE AND _A. W. BENNETT, M.A., B.Sc.,~ ¥F, JEFFREY BELL, M.A., Lecturer on Botany at St. Thomas's Hospital, _. | Professor of Comparative Anatomy in King’s College, $0. RIDLEY, M.A., of the British Museum, ssp JOHN MAYALL, Jex., , FELLOWS OF THE SOCIETY. ' WILLIAMS & NORGATE, : : LONDON AND EDINBURGH. . PRINTED BY WM. CLOWES AND SONS, LIMITED, } {STAMFORD STREET AND CHARING CROSS. C2) JOURNAL OF THE — “ROYAL MICROSCOPICAL. soommry. Ser. 2.—VOoL.L. Ile PART 4. (AUGUST, +BB2) Cun iers TRANSAOTIONS OF THE: SooimetTy— 2 < rae oh oe PAGE X.—On some Micko-oRGANISMS FROM “Ravwarm low aa Ham. pe bets By R. Li. Maddox, M.D., Hon. F.R.MS;&. .. 2k. 449° XI.—Tae Repation or APERTURE AND Powsr IN THE Mronoscorr ; (continued). By Professor Abbe, Hon. F.R.MLS... .. .. 460 X1I,—Descrierion or a Suupia Pray or Impeppina Tissuus, For Microtome Curtine, in Semi-punpep Unenazep Printaye Parrr. By B. Wills Richardson, F.R:CS.L, Vice-President _ University of Dublin Biological ‘Associa PAE he anes ece NM Shy. Le Bie XIL —NotE on THE Rey. G. L. Mus’ PAPER on Diaroms: ji. Nes Peruvian Guano. By F. Kition, Hon. F.RMS... .. .. 476 Summary or Curzent ResEARCHES RELATING TO ZooLoay AND Borany (PRINCIPALLY InvERTEBRATA AND Cryprocamma), Micro- scory, &c., INCLUDING OniGinaL Communications: FROM FEutows AND: OTHERB. "oS. foc) wa 26d SS es coy eat > ee ieee ea eae eS. _ ZOoLoey. Sep ee OR BaP aD Division of Embryonic Cells in the Vertebrata, 2 s00 2 Si Des gure Pam 7, ATS Genesis of the Egg in Triton .. —.. eerie, risiry yy Sane Bryce 7 Rage Formation: of Bibrine se) sed ide) we hse se Mae vo tp ae eee ina ee Bi pale New Blood-corpuscle . en eee A RRR io eons MRR aE OD Life and Death in the “Animal Organism .. Jo Wika eet wt heh Gemeeieed Cast FS Pelagic and Deep-Sea Fauna ., sede aS phea tae Ne Gad tebe A es tL: Anatomy and Classification of the Cephalopoda LORS eas A ee gee eae ES Ink-Sac of Cephalopoda .. _.. +: oe beet obats gay ae oe Og. Sense of Colour in Cephalopoda es Pipenmeninie, mkt F-sceary a yee ible tS ‘ Foot’ of certain Terrestrial Gastropoda PE SMS kG IT eRe Te Mucin of Heliz pomatia .. .. wee ER age 0k apes Mike wipe itr tatet eet Rhodope veranii .. — «. Be Fr abies) GEM CK Beli chibe SMS RMI ia hele ae En Vest.Cells%in Ascidian.Ova SL meen earn are IPSS S wicstam I a Embryology of the Bryozoa Paes eee Pa ae Tamar y HUE ahs eran: ee Nt ty New Adriatic Bryozoa«. iF eel, SOE Sensations of Sight conveyed by ‘the F aceb-eye @ igs 88 aad i) Pe oe |) ae Nervous System of the Strepsiptera.. «. as ver ae) 499 Insects which injure Books VR ae oe ee alan A PENRO ECO PEM ee ae Ra ROD Formation. of Galle: oe i iyioe ter mabe ad aby Vola Chat eda tae es Anatomy of Phalangida .«. reer ty aaltes et AS) | 5 Aree Scent-glands of the Scorpion-spiders (Thalyphonas) PGi ne Satm tchios Metab aera tee, Classification of the Brain of Crustacea...’ .. Bb da ye en a agen oe Unpaired: Bye of Crustacea): 50)... oar ay ees ian) ole) aa eee PE Blood of the Crustacea... Bago igs Sg gh A a aE ee Pyloric Ampullz of Podophthalmate Crndacea se sh pee - 805 Heterogeny of Daphnia. 2» es ewe tee te ae wn a 906 i ee a eee RAE HBS MK = ‘Summary or Current Resmarones, &c.—continued. : PAGE : Notodelphyide .. (ARS Sita ie A 506 rare Organization of Trilobites .. UG Tones SORT Ta oO Tet Papel Set Chemical Composition of Tubes 0 af On Onuphi He SNES ey hey eee ROT RR Nematotd Hematozoon from a WILE Ae ESOL ee SERS oe OM Development of Marine Planaria: .. + ee te pete te ne we BOD Eyes of Planarians .. SAR Mahe Se PMRCONE Lte hee Q he Sek LO Development of the Orilionectida. Sie GaN SGN Se Rad ORR AS aiaae TAR ei , Byes of Rotifers .. .. as 65 EN See One ata eo DE ge ees Cee Ee Anatomy: of EHolothurians: 3. ise 58 eek. fee tap tees anes ey, ee OAS Hybridization of Echiinotdea 4+ ss ee ee ne ne pe we ee ne BIB Variation in Asterias glacialis ... .. CVE be eke cow OLS ~ Development of Calcareous Skeleton of Asteroides - PPE Sr a RUE ELC RUS) 3 Development of Ziquorea .. RIESE rial amass IR PETe GL eee Fi) Hybridization in Fresh-water Sponges UR Seer UNE i Py he ees Boring Sponges Barrie § Cae pee N aw Neal? oa. t Rae RS aN RRR, eee OLO De Lanessan’s Protozoa .«. SEU y dys Rage Peipaning ait ipta, ad one e mundo Kents Manual of the Infusoria es, SREP sae gt SE ERO eee IR Flagellata .. ies Ae OLS Cell-parasite of Frog’ ¢ Blood and Spleen (Drepanidium ranarum) SAR ieee Sy Development of Trypanosoma... «+ +. Dae, Pett aby Spee UOeD : _ New TE GOUPINAE Ge ek had SR oe ae aa Seg PAP pee Nance ae Oe Chemical Difference between Dead and Living Protopasm (Fig. es +» 522 * Killing of Protoplasm by Various Reagents .. ¥ Sek em ree Apical. Cell-growth in Phanerogams..0 6 ek ne te ee oe ee we 528 Development of Bordered Pits .. Se ene TOee ‘Development of Tissue as a Characteristic of Groups of. Plants same aeY | Stomata of Polycolymna Stuarti .. Pee ep ae HOE Properties and Mode of Formation of Duramen .. sl ft be oer) OD History of Assimilation and of the Functions of Chlorophyll PARRY Theoretical View of the Process of can zie og fviga. ew n dae _ First Products of Assimilation... — .. Sects (om Subba ee NP RS anh eae ae - Absorption of Metallic Oxides by Plants... 526 Decomposition of Calcium carbonate tn the Bre of Dieters Woods 527 * Hypochlorin.. .. oe big ak Sales sole Sooke (aes ORS - Latex of Euphorbia Lathyris a ges) ag ee OSE Darwin's so-called “ Brain-function: ” of ‘the Tips of Roots « oR a RaRA edt hee. OGD Aerial Cultivation of Aquatic Planis' .. pe Saat phi pe ye Seon TNGerlecOrOUs: LLGMtA Seve. vege iube oy ate oar EARS A AAS IESS Oe ee) OBL Climbing Plants ...:. bit Re GR ww ety s 12S Sap ce hy ae Ae ls ope RPE Power of Movement in Pigteis \ Siskaeo Sia ae si ep Sk: Nr Pied er bee ODE Electrical Researches on Plant Forms... Seat neya ee WN ee ate Oe Electromotive Properties of the Leaf of Dionza .. x dee dette shea woe ~ Influence of a Galvanic Current on Growing Roots... ws ee ee 583 Schizeacee .. . SO AP Seah a che She tack Oh lasek A TRAN OR Branched Sporogonium of @-Moss .. ee ee ete en Tr aeoer tae Influence of Light on the Thallus as Maréhantia. SS eaety ave OEM Oe RENN «5 Goebel’'s Musciner — .- Fite CW IRS ped Shee pk ae Doe Development of the Cortez Si Ohta ce Sgt gS ey GN OBB Ustilaginer.... ir raS ek ts st Aiadas a ste ig lo. by we OG Unobserved Sensitiveness in Phycomyces Rae Oba t ans Guan as TE CaaS gan pe OD Beltrania, a New Genus of Heghomyeates Pa ah aaa ait ier Ur Se Chemical: Composition of aes * Pees ahr ae Visie te a eek, OUR Salmon Disease... «s 538 Formation of Saccharomyces in - Nutrient Fluids containing various Pro- portions of Nitrogen .. han hues ve, SSE Morphology and Genetic Relationship of Pathogenous E Bacteria... 1. 541 Bes - “Pathogenous Bacteria... °.. Boe DS ves Mae sR Tec 2 Rak 3 Bacterium of Charbon .. he! apeedp ate) ag aaa ve TC wok URS ee pa Pe Connection of Bacteria with Ferments Mane teey 2 hak sake or ug eats Gar base taek SE Life-history of Cora... sR pak s Tete ete) ulus eles te ces t kaeee Minks’s Licheno-mycological Symbols ib EUR PRT Spee Sle ae ak arya c the Symbiosis of Alge with Lower Animals... 2. ee tee ae we ee, 4D Division of the Cell-nucleus in Spirogyra ogres PME GHy aes Sends LORD (ay ‘Summary or CURRENT Reseanonns &e—continued. PROCEEDINGS OF THE SOCIETY phi ace aieh NIB eee goat eee 549 ae 909 O78 BI 878 aT: Pi aoe PAGE. Batrochospermimn |. 0 OC a eon eck ae eee tec Oe iene tae CAE New: Beg geet. os te a OR EP Ie pti ay Saat ay een HEA (MGM YP EN a on Soe Mea Eee Cn, as oe a ae Sede he ee epee ae OE Schizophyces. SANT We OF askin: hae seine Oa Sa ReMi aint ee OURERS me ae i neem aes OME Ly Mobionaf Diabaig: 252. GO gh POL ag a oe sae eg ee : Microscopy. Pei g sir: ae Re Lossner’s Tele-microscope .. .. Lk ON Jae og eh aia! DEE Prazmowski’s Micrometer Microscope (Fig. 91) ee erg th Simplified Reading Microscope for horizontal and vertical sive ROW Nea, Swifts Tank Microscope (Fig. 92) .. Rapier etree. Oa Leasdale's Field Naturalists Mieroscope (Figs. 93 and 94): bce Trae S Nes, BESET Steinheil’s Achromatic Eyepieces (Figs. 95 and oy Si Vides Mawel ales Aiea «eka New Combination for Objectives 2. uae Gah SGth saana aay tue et RO DE. Fluid for Homogeneous Immersion .. Sol Shurley’s Improved Slide for the Examination of Gaveo Dialer Orig ” 551) Hardy's Compressorium (Fig. 98) -... 4. ws aaa hae Rane ee Bulloch’s Diatom Stage ~ .. Soe aa Re aden eer rede Substage Fine-adjustment (Fig. 99) .. Rae atno Pancreas ee ee at ES Sidle’s Centering Substage (Fig. 100) ied aps OOS Mounting for the “Woodward” Brink (Figs, {01 and. 102)’. magnesia rh ag 3H Prisms versus the Hemis; herical Leng as LUNN ie AOD nae ues 4 Pate 3411 Hadial Tail-pieces’— .. em ear cael wey y Electric Light in Microscopy Pigs 103 and 104). TERCERA ek OEE Black Backgrounds .., pets epi ey Apa se BO Micrometrical Measurement by means “of Optical Trages OF eh a irs Be aay ~ Malassez's Improved Compte-globules (Figs. 105- ae her dat haipeeanaarat Cutting and Mounting Microscopical ones Bao bh hae k BOL ay eee EE Preparing Blastoderm of the Chick .. se. 41 ee eu ee te te ea TO Preparing Embryos of Insects .. *. eb Yale SN Ree eae iaabac Ce Collecting, Staining, and Photographing Babteria say Cc ee eee OTL Ehrlich’s Method of Exhibiting the Bacteria of Tuberculosis Wi fyam Siders DIS Preserving Infusoria and Amebe 6. te cee ne ee eee TA Preserving Protozoa. .. Cae “a ahe eA eee Bac tae ne Ege Staining the Nucleus of Living Infusoria... PR ey tee eet Mr Lan em Double Staining with Carmine and Anilin Green .. Ry ied eRe egies AOE Cutting Sections of: Coal: vi) 5. Sa Gal Say eae ee wa ee a ONE Bections of Miea-sohiiat 56a eee, a an ae eee etee. OTS Paper Cela riot oe ags® ook icp ae pix decal eae a el ga ane ike eel ea Wax Cells ne ae . oe SAE oe Rk we pat 5 ee ae bacpcare cur 578 Miller’s Caoutchoue Cement. sss es tn ae Mounting in Phosphorus ee aham nie gang Seal on eikan Naas eee eee Vacuum-bubbles in Canada Balsam . Pea Nias i WR Soin Sh RIO OA Patt eR ole Mounting Moist Objects in Balsam. jodi) aan gs alga aw © toe chee eek (DOA | Moisture in Dry Mounts’ .. °.. as Sa pV gE A Ge ea ea Dammar Varnish j yb 60 enw iy Sy te neon ae eee Oe Cleaning Used Slides and Covers oUg og ol Eadie” aah hE Cae ay RE AI BE Resolution of Amphiplewra pellucida... 24 ce ce ae ne ak ne ee BEY Microscopie Examination of Wheat -flour .. x5 ine Weds 3 pe etek DOS Destruction of Microscopical Organisms in Potable Water ye We tga on 2 OOD. Public Lectures in. Microscopy *+s 55 os. a a ke he nee ae 585 589 (8) AHopal Aicroscopical Society. “MEETINGS FOR 1882, . AT 8 P.M. 1882. Wednesday, January... 6. we % FEBRUARY .. sein § (Annual Meeting for Blection of Officers and Council.) us Marcu 8 Be APRIL .. 12 y May | 10 5 JUNE 14 be OcTOBER FOS SIERO Peake Bs OMe Supe > | 5 NovemBEeRr . DeowMBeR Hi Fe Se PAS THE ‘SOCIETY’ STANDARD SCREW. The Council have made arrangements for a further supply of Gauges and Screw-tools for the “ Socrery” Sranparp Sorew for Ossxorrves. The price of the set (consisting of Gauge and pair of Screw-tools) is 12s. 6d. (post free 12s, 10d,). Applications for sets should be made to the - Assistant-Secretary. For an explanation of the intended use of the gauge, see Journal of the Society, I. (1881) pp. 548-9. ADVERTISEMENTS FOR THE JOURNAL. Mr. Cuartes Burncowsg, of 75, Chancery Lane, W.C., is the authorized Agent and Collector for Advertising Accounts on behalf of the Society. (6) “COUNCIL, ELECTED 8th FEBRUARY, 1882. re PRESIDENT, : Paar. Pe Marin Duncan, M.B., F.RS. ~ VICE-PRESIDENTS. Pror. I. M. Baxrour, M.A. E.R. S.. . Rosert Brarrawaire, Esq., MD. MBC. S., FL, g. Rosert Hupson, Esq., E.RS,, ELS. JoHN WARE STEPHENSON, es BRAS. a TREASURER, Sa Lions 8. ‘Beare, Esq., MB., FRCP, ‘ERS. SECRETARIES. OHARLES Srewarr, Esq., MLR.CS.,. FLS. oe Fran Crisp, Esq., LL.B., B.A, VP. & ‘Tras. Ls. Twelve ather MEMBERS of COUN cI. Lupwie Dreyrvs, Esq. CuAaries James Fox, Esq. Jamus: GLAIsHER, Esq., F.R.S., PRAS. J. Wirt1am Groves, Esq. A. pE Souza Guimarazns, Esq. Joun KE. Inaprn, Hsq. Joun Mayatn, Esq., Jun. Aupert D, Micwazrn, Esq., F.L8. ; JouN Minuar, Esq., L.R.CP. Edin, F.LS, Wii1am Tomas Surronn, Esq. Freperick H. Warp, Esq., M.R.C.S. T. Caarrens Wurtz, Esq., M.R.CS., FL, 8. Ne, eg I. Numerical Aperture Table. . The “Arerrure” of an optical instrument indicates its greater or less capacity for receiving rays from the object and ee transmitting them’ to the image, and the aperture. of a Microscope objective is therefore determined by. the ratio’ between its focal length and the diameter of the emergent pencil. at the plane of its emergence—that is, the utilized _ diameter of a single-lens objective or of the back lens of a compound objective. This ratio is expressed for all media and-in all cases by sin w, n being the refractive index of the medium and ~ the : Semi-angle of aperture. ‘The value of n sin u for any particular case is the ‘numerical aperture” of the objective, __*~Diameters of the Angle of Aperture (= 2 1): Theoretical | 5, Back Lenses of various oo Ilmi- Resolving ene-. Dry and Immersion | Numerical Watéer- | Homogeneous-| nating | Power, in _ | trating ‘Objectives of the same | Aperture. Dry cae Zevsneasion Power. | Lines to an Inch.| POWer- Power (3 in.) (w sin w= a.)'|: Objectives. } ob iectives,|° Objectives. |. (a4). |~ (A=0°5269 u (2) from 0-50 to 1-52 N. A. (m= 1) l(a = 1-33.)) (m= 1°52.) =line EK.) a Beta crear eal 1°52 180° 0’ 2:310 146,528 “658 1:50 161° 23" }2°250| 144,600 “667 1:48 | 158° 39° }2-190 |. 142,672 676 1:46 | 147° 49" |2+132) 140,744 “685 1°44 | 142° 40’ |} 2-074; 188,816 “694 1:42 138° 12’ |2*016| 136,888 “704 1:40 - | 134° 10’-/1-960! 134,960 “714 1°38 - 130° 26’ |1°904| 138,032 “725 1:36 126° 57’ |1‘850) 131,104° | +735 See 2 123° 40’ | 1-796! 129,176 - | _-746 : © 9’ 122° 6 1°770; 128.212 “752 130 tae me io 33) pee ats pe 1:30 155° 38"; 117° 34" |1-690). 125/390 | . «769 1:28 148° 98'| 114° 44" | 1-688. 123,392 “| -781 . [o} Ua) oO rit . § Pied ee POGUE Rete CRO Barer keer 1:22 133° 4"; 106° 45’ 1-488; 117'608 | +820 ; >] 1s fase. 8/1 40 en |4-aoat 18/758. | ee 1:16 121° 26’; 99° 29} 1-346) 111,824 “862 is Tee eee rd rp ae ihe ai ee r| “7 | 4-2: 7, 4 Be pon eS) Las meee 1-06 f wos art Se oe. 1 aba 102,184" | +943 1:04 102° 53’| 86° 21’ | 1-082! 100,256 “962, - 1:02 — i 100° 10"|- 84° 18’ |1:040| 98,328 |- -9g0 1-00 |} 180° 0 | 97° 317} 82°17’ 1-000! 96.400 | 1-000 0-98 .| 157° 2°} 94° 56’ 80°97"! ~960) 94,472 | 1-020 0:96 147° 99" | 929 24)" 78° 20" | +992). 92,544 |-1-042 0-94 +.140° 6’ | 89° 56’ 76° 24’ | -884| 90,616 | 1:064 092 | 138° §1’ | 87° 32'| 74° 30’) +846|. 88,688 | 1-087 0:90 128° 19’-|-85° 10’| 72° 36’ |- -810! 86,760 | 1-111 0°88 123° 17% 82° 51"|. "70° 44’ | 774." 84,832 | 1-136 0:86 118° 88’} s0° 34’| : 68° 54’ | +740; 82,904 | 1-168 0:84 114° 17’ | 78° 20"! 672° 6’ | --706! - 80,976 }'1-190'- 0-82 | 110° 10’| 76°. 8’) 65° 18’ | +672) 79,048 | 1+220 0:80 106% 16’.| 73° 58'|.. 63°31"; +640|. 77,120 | 1-250 0:78 102° 31’ | 71° 49"|~ 61° 45’ | -608| 75,192 | 1-282 0°76 98° 56’ | 69° 42'| , 60° ..0' | +578) 73,264 -| 1 B16 0°74 95° 98! | 67°36") 58° 16 | -548|} 71,336 | 1-351 0°72 92° 6’ | 65° 82'| 56° 32’ | -518{/ 69,408 | 1-389 0-70 88°51’ | 63° 31’) 549-50" | <490|*. 67,480. | 1-429 0:68 85° 41’ | 61°80’! 53° -9” |. -462 65,552 1°471 0°66 82° 36’) 59° 30’) 51° 28’. | -436} . 63,624 | 1°515 0:64 | 79° 85" | 57°.31’) 49°48" | -410/- 61,696 | 1:°562 0-62 76° 38'| 55° 34’). 48° 9’ |- +384! 59,768 | 1-613 0-60. | 73° 44" | 53°38} 46° 30° |. -360!. 57,840. | 1-667 0:58 70°. 54’ | 51° 42’| 44°51’ |. 836] - 55,912 |.1-724 0°56 68° “6! | 49° 48’|- 43° 14/ }<314| 58,984 | 1°786 0-54 65°22" | 47° 54’) 41° 37° | +292) 52,056. 11-852 0-52. “62°. 40" |46° 2} 40° (0% | +270! © 50,128 | 1-993. - 0°50 60°. 0’ | 44° 10’| 38° 24’ | -2501 48,200 -| 2-000 Exampite—The apertures of four objectives, two of which are dry, one water-immersion, and one; oil-immersion, would be compared on the angular aperture view as follows:—106° (air), 157° (air), 142° (water), 130° (oil). | Their actual apertures are, however, as 2 *80 “98 1°26 1°38 . or their numerical apertures. Scale showing || the relation of Millimetres, &c., to Inches, mn. _and em. ins, ESTES PRG Se SO ACEI ARE BST IS, SURE) PETES A DASE ESTA Pee SAE FEC eel BRE bt ee eR SR Ee 7 — ‘= ] a a a im : a | a a a tI mi | J rs a a @ m aS i a a | | 5 | | ml 000. =1 mm, 10 mm.=1 em, 19 om. =1 dm. 10. dm. =1 metre, II. Conversion of British and Metric Measures. = = = = ~~ : . (1) Lineau eta roh SLMS ie ch Cpa Aa manna Rs Micromillimetres, §c., into Inches, Go.) | * Znohes, &¢., into: we) ins, Bynes ele, Smee iene . hen ae Ceo ee 1 +000039| 1 089870} BL: yo 2007892) ine yy, 2 -900079.| 2 078741 | 52 2.047262 | 3 1-015991 3 000118} 3. 118111} 53: 2°0866383| =°5°° - 4.069980 _ 4 -000157| 4. "157482 | 54 24126008}; 22322 4-g93918 5 +000197| 5 196852]. 55° B165874 | PP? 9. Ba 9977 6 -000236| 6 9936083 BE. es o0aTaas |) COIER 5 o50707 7% QOOQTE! i: 7278503) D7 2DdNb | A 3.974979" 8 -000815 | 8" *314963 | 58 |) 2283485 | FPPO B.gogsag 9 000854; 9 --B54384/ BO 81802 | F9PO | gabon 10 000394} 10 lem.) +898704| 60 (6cm.) 2-862226) 799° 5.q7o954 11. -000433 11 -*488075 |; G1. 2°401896 | acon 6° 349943. 12) :000472| 12 6472445) 62. |.) 24409671 “su55 8 °466591 13 +000512 | 13: 511816} 68... 92480887} adoq 127699886 14 :000551| 14 “*551186} (64 27519708 | x55" 29°399772. 15. -000591/ 15 = 590556 | 65: “(2 550078 he Aga 16° -000630 | 16 +629997| 66. > 2598449 | oo 028222 17 000669 | 17 “16692971 6%. 2687819} soo, “081700. 18 °-000709:|' 18 #708668 6B... Br877180 [> too! USRR8S. -19 +000748| 19 ©. 748038 69°). 2716580) apo | OBB 3S 20 -000787 | 20 cm.) -787409| 70: (7 cm.) 2°755930 | sea del 221 0008271 BES 88770 I Meo! 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(Cz) ‘pontujuoco—SeINsBey Siar pus epee jo ‘WOTsIEA TION ven oA L88660- 19 SF8ZZ6 + FS 608028 - 8b TLLLIL- GF GEZSI9-9E £69ZTS-08 CCLOLF- FG 9L9LOE + 8T LLOGOG- GI - 6801-9 C8Z66F-S 160G88-F LLLILZ“¥ 8ZS199-& 69G1S0-$ STOLPE:S Z9L08+ 80026-I FEZ0T9- 8ZZ6PS- - $0G88F- SLILGP- GST99E + LGIS08- GOLPFG- 9LOES8T- TS06aI- ¢c0T90- "pup 7qno an 1D 000T 006 008 0OL 009. 00¢ 00F 00 00% Creer D. 00t 06 0g OL (q099. 1) OF “BOyTITUU “of ‘soyour orang opus “Of ‘so.anuntAe (10 ) II. Corresponding Degrees in the | IV. Refractive Indices, Dispersive _ Fahrenheit and Centigrade Powers, and. Polarizing Scales. nt, ATO es Se eRe Fahr. Cent. Genki. = Fahr. en (1.) Rergacrive Iypicus. BOG 260) O19 1B. 2 3912-0 a : eee is 232°22 98 208 °4 tamond | 400 . 204-44 -96 » 2 204-8 a 350 - 176-67 94 FBO Be |S ROSPHORUS oes 300 148-89 92 197°6 || Bisulphide of carbon ie ae eee Bis 6 = Ao?) ee ee 210 ——-98-89: | 86 186-8. || Crewe Blane | 205. 96°11 | 84 - 183:2 || Rock salt ae 200 93°33 - 82 179°6 rhe ip: 195 90°56 | . 80 geo aes --190 87°78 78 - 479-4 || Linseed oil (sp. gr. 932) ane ee 185 89:0") 76 168-8 || Oil of turpentine (sp. Br 888) Uae 180 80-00 Loe en Es: 175 79°44 72 161°6 Sete a ied 76:67 70 158°0° || Sea water ep 1 73°89 68 154:4 || py i ek ihe 2) me zt 55 68*33 > 6 147°2 : a Baie ote , less and }; more than the figures given in this column, ‘HENRY CROUCH 1s : First-Class Microscopes. ! "Student's ‘Microscope. ‘New Family, and School : _ Microscope, — ; \ | New Series of Onjectives, Y New Accessories. NEW ILLUSTRATED ae ON RECEIPT OF ‘STAMP, LED ABROAD FREE, ; HENRY CROUCH, 66, farbleah London, 5 o. AGENTS IN AMERICA, JAMES W., QUEEN & 00., 924, es Street, Be v 8. JAN 20 1903 NEW YO RK BOTANICAL JOURNAL Ai Sesatnci OF THE ; ROYAL MICROSCOPICAL SOCIETY. AUGUST 1882. TRANSACTIONS OF THE SOCIETY. fe X.—On some Micro-organisms from Rainwater-Ice, and Hail. By R. L. Mappox, M.D., Hon. F.R.MS., &. (Read 10th May, 1882.) Tue study of the minute organisms belonging to the Schizophytes is one of special interest, for they touch the final history of all living beings, and very possibly hasten, if they do not actually cause, premature death. The researches within late years by very able microscopists and members of the medical profession have been numerous, though far from exhaustive. They embrace almost every field of inquiry, as the valuable Summary in the pages of the Journal of the Society so well attests; hence, some one may have preceded me in similar observations, as ice, hail, snow, rain, and dew have each been often examined; I am not aware, however, that the points I have to mention have been specially noticed; and I therefore trust they may not be wholly devoid of interest, even in their incompleteness. The winter of 1880-81 was of considerable severity from the ex- treme cold, which if already forgotten, allow me to recall to memory, by stating the fact that at my residence, one day whilst at dinner, with a good fire in the room, water when poured into a tumbler immediately became a mass of beautiful ice-crystals. The out-of- door temperature for several days was such, that the rain-water in the open garden rain-water butt was frozen to the depth of more than 12 inches. When the thaw occurred, I placed a large block of the ice, after well draining, in a clean new pan, and removed it into the house, set it in a fireless room, and covered it carefully from the dust.. Three days later I noticed a thin scum extending over the entire surface of the water in the butt, and at once put some on a slide and examined it with the Microscope. It was found to be a mass of micro-organisms lying in a pellicle inter- mixed with particles of soot, dust, and a few minute oily-looking Ser. 2.—Vor, II. 2H 450 Transactions of the Society. globules. The organisms differed from any I have ever noticed before or seen figured in any papers treating on Bacteria. Slides were prepared, some without staining the objects, others by staining with aniline blue, and much later on were photographed, using a +-inch objective and artificial lamp-light. The exposure upon the (commercially so called) “instantaneous” gelatino-bromide plates varied from four to five minutes. The negatives, from deficiency in actinic power of the light employed, were too thin to furnish fair paper prints; hence they were copied upon wet collodion into positives, and these by the same procedure into denser negatives with some enlargement compared with the originals. The micro-organisms in the pellicle, as seen under the Micro- Scope, appeared as minute rods or joints very irregularly shaped, and most of them larger at one end than the other, being either club-shaped or like the handle of a pistol, possibly due to the formation of a spore at that end, though this is doubted by some, for many had lying upon or near to the thick end a round or oval body, as if it had escaped from the adjacent rod. Some of the little bodies tapered gradually from the thick end. Where the placing of the pellicle on the thin cover-glass had not much disturbed its condition, the organisms were seen to lie very generally side by side, though not evenly, and in more or less slightly curved lines, as if the growth had been in a longitudinal direction upon a gentle curve, yet not giving rise to the sharper curve seen in many of the rods forming the mass. Amongst the numerous figures given in the ‘Annuaire de l’Observatoire de Montsouris,’ for the last three years, by M. Miquel, of the various micro-organisms he has found in the air by daily systematic observation, I have not noticed one similar to the one described. Besides these organisms there were a few small bodies in the pellicle, looking like ordinary bacteria and micrococci; but the general mass in the scum con- sisted of the large forms. ‘Their size varied considerably, the large ranging from the 75, to 45 of an inch, and the small of the same kind, to little more than half this length. Whether these bodies should be placed in the Schizophytes as Bacteria or Bacilli, I was doubtful, as more experienced observers than myself differed in opinion. No movement was seen in those freed from the broken edge of the pellicle. The difference in shape from the ordinary Bacilli rods might have been due to hindrance in their development from the previous severe cold, though if confirmed in future observations, it may be of a specific character. The block of ice removed to the pan, furnished on the third day a pellicle which was much thinner, but contained exactly similar rods. There was considerably less contamination. ‘The same was examined at different periods, and after remaining undisturbed for more than thirteen months showed the rods to differ but little from On Micro-organisms from Ice, &e. By Dr. Maddox. 451 the original ones ; being rather straighter, the club or pistol-handle shape still very evident, and the rods in somewhat more regular position. From the result of my rough cultivation experiments I am inclined to regard them as Bacilli. A few cultivations were attempted with the pellicle from the water-butt, also from the pan. For instance, I tried to cultivate them in sterilized (i.e. by boiling) normal urine, in sterilized infusion of Liebig extract of meat, upon cold boiled potatoes and the white of hard-boiled egg, without increased temperature beyond that of a fireless room, but with no positive success. Yet eight months later a speck taken from the pellicle, removed with some of the water from the butt at the time of the original observation, carefully kept covered and un- disturbed, and which contained the club-shaped rods in abundance, when placed on sterilized gelatine jelly prepared with infusion of Liebig extract of meat, showed ready growth in the rods, some to more than twice their original length, others multiplying into short joints. In the long ones the characteristic irregularity of outline was apparent in very many. The growth from two minute specks placed one at each end on a layer of the jelly, poured on a scrupu- lously clean slide, soon covered in length the intervening distance of an inch. Curiously, they were more or less arranged in circular groups, the centre being often occupied with a beautiful rosette of some salt crystal, though the individual rods were without regular arrangement, the short rods crossing each other in all directions. After such an interval it would be hazardous to say they were all derived from the club-shaped rods. What I wish to note is, that they grew into longer ones, so to establish their claim to be placed amongst the Bacilli. Later still, in the month of April this year, some of the same pellicle was sown on peptonized gelatine jelly without any evidence of the growth of the rods, and at the same date some placed on hard-boiled white of egg offered no change discernible, though in both cases there were very many minute organisms, as bacteria and micrococci, in Brownian move- ment. I may note that Mr. M. A. Veeder, U.S.A., found that various infusoria, conferve, &c., in the sediment of the clearest parts of blocks of ice from stagnant water of ponds and canals, would revive when melted, and considers such ice doubtful for drinking purposes. I will now pass to some remarks on the micro-organisms found in melted freshly-fallen hail. A rather heavy hailstorm happening on the 25th of last March, I took the opportunity to collect some of the hail for ex- amination while the storm continued, by dipping a perfectly clean tumbler into a drifted heap lodged in one corner of the window-ledge, without touching anything else ; immediately cover- ing the tumbler with a clean plate of glass, and msn be hail 2H 2 452 ‘Transactions of the Society. to melt in a room without a fire. On the second day a faint scum was visible on the surface in patches, enveloping grey, soot-like particles. Some of this pellicle seen under the Microscope showed very pale, motionless organisms lyimg in it, resembling rather elongated micrococci. ‘The water was left further undisturbed for another day, but furnished no appreciable difference except greater distinctness of the imbedded organisms. Some of the pellicle was stained with aniline blue, and mounted in acetate of potash solution without having been dried. Whether from want of refractive differentiation between the objects and mounting medium, or from the acetate of potash acting upon the pellicle, the outlines of the minute organisms were indistinct ; consequently a different method was adopted, which seemed to offer advantages. A speck of the pellicle was placed, with as little disturbance as possible, in a droplet of distilled water on the cover-glass, then, as recommended by different observers, dried over a flame, in this case very slowly. Afterwards it was covered with the following staiming fluid and protected from the dust : — Bismarck or aniline brown (of German make), 4 grains; citric acid, 16 grains; distilled water, 200 minims; boiled in a test-tube, cooled, filtered, reboiled, and a trace of carbolic acid added. After being covered with the staining medium for an hour it was washed with distilled water by tipping off the fluid, draining closely on blotting-paper, repeating this until the water was colourless, then drying again by gentle heat and mounting the cover dry. Deion I tried the aniline brown without the citric acid, but the addition of the latter appeared to facilitate the washing by increasing the solubility of the colouring agent without lessen- ing the staining qualities. Great care was required if the specimens were washed with the cover on the slide, for the least displacement caused the pellicle with its organisms to roll up into continuous lines. I am not prepared to say that the method of drying does not slightly shrink the objects. I fear it does, though I do not think more than osmic acid, as the substance enveloping the organisms appears indistinctly afterwards. The minute bodies found in the melted hail differed most completely from those of the frozen rain-water. In parts where but little disturbance of the pellicle occurred upon removal for examination, the organisms were seen lying very irregularly near to each other, whilst in what appeared to be a second pellicle formed just beneath the outer one, they occurred mostly in rows, and are often at rather an acute angle with one another. In size they differed, doubtless owing to being in various stages of growth and fission. On Micro-organisms from Ice, dc. By Dr. Maddox, 4538 The average size is from the szioo to the rstoo of an inch in length ; some looked round, others like elongated micrococci, and when fission was about to occur very like ordinary bacteria. As they were when free motionless, I felt inclined to suppose them to be micrococci, but from some cultivation experiments I believe they must be termed bacteria. Thus a speck of the pellicle was placed on freshly boiled white of egg, and kept carefully covered and turned down without touch- ing anything except by the broken shell edge. The second day, about thirty-six hours after the inoculation, on removing a minute portion and diluting it with distilled water, it presented an in- credible crowd of bacteria in rapid motion, resembling closely, if not actually, Bactertwm termo. On the sixth day the white of egg, at the spot of inoculation and for some distance beyond, pre- sented a beautiful pale canary-yellow colour, and on the eleventh day a bright deep rose-coloured spot also appeared, very closely to the seat of puncture, consisting of motionless micrococci. This has been successfully cultivated ‘through several generations on the same medium. A portion of the original pellicle placed on peptonized gela- tine jelly on the thin cover, and this placed over a tin cell cemented to an ordinary slide, ‘the surface of the tin circle being smeared with vaseline (as recommended, I believe, by an American microscopist), except at two small opposite points, and then kept at the temperature of about 58° F., had on the second day so softened the gelatine by the changes induced in it, that the spot of inoculation was quite fluid, teeming with minute organisms in most rapid motion ; hence, as several inoculations were made, and with like results, I conclude that chiefly bacteria and only few micrococci existed in the hail in a quiescent or resting stage, and when supplied with proper nutriment and more favourable condi- tions, the organisms, suited to the circumstances, quickly turned from the quiescent state to one of the greatest activity. Of course I do not pretend there may not have been different varieties in the hail, for the organisms of rain-water have been found to determine butyric, lactic, ammoniacal and putrefactive fermentation; but what appears to me probable is, that one if not more amongst the organisms supported the temperature, whatever that might have been, that determined the formation of hail, remaining in an almost quiescent state, for I believe the Bacteria have their resting stage, and that the more advantageous conditions of nutriment and temperature speedily determined activity. The general mass of the jelly remained free from visible change. Before actual fluidity of the material occurred, close to the inoculated spot, numerous small, round, grey, finely granular, ascococcus-looking 454 Transactions of the Society. patches made their appearance, and gradually coalescing, joined the edge of the inoculation. Of their nature I can say nothing definite. How they came there is rather puzzling, seeing none formed in other parts of the jelly. At the same time, and in a similar manner, the same nutrient medium was inoculated with a speck of the old pellicle from the ice in the pan: the club-shaped rods did not, at this date and in this medium, undergo any visible change ; but some of the minute organisms showed development, though not to any great degree, only exhibiting Brownian movement, whilst some of the same pellicle placed on the boiled white of egg at the same time as the former experiment with the pellicle from the hail, furnished on the second day minute organisms which, when seen in a droplet of distilled water, were not very active; but the club-shaped rods, if they multi- plied, did so to an indiscernible extent. ‘There was no chromo- genous change at the point of inoculation, as with the pellicle from hail. The minute organisms found in the melted hail-water scum, were no doubt derived from the rain-drops congealing round the air-borne dust-particles to which they were adherent, and after- wards slowly multiplied afresh on the surface of the melted hail. Some have doubted whether bacteria form part of the atmospheric dust; but the very careful experiments and cultures of M. Miquel, at the Montsouris Observatory, tend to prove that such bodies are suspended in the air and to be constantly found in rain, hail, and snow. Numerous figures are given. ‘To avoid contamination in culture experiments, when objects are only for a short time exposed to unfiltered air, is a great source of difficulty. M. Miquel remarks in the ‘ Annuaire,’ published this year, that snow, usually regarded as the great air-purifier, is not so in reality, for although it largely attracts the bacteria it meets with in its passage, it does not fix them like moistened earth; as a sudden squall cutting into the snow will often again bear them aloft. January and February have furnished him with the minima; October and November with the maxima in the gatherings. Cold he places the first, and extreme dryness the second agency in the destruction of atmo- spheric bacteria. Rainfall much lessens their number, whilst this again rises upon the succeeding dryness. He finds them ten times more numerous in the centre of Paris than in the country, for the same volume of air, and he gives the proportional numbers as, micrococci 93, bacilli 5, bacteria 2, for the first, and micrococci 79, bacilli 14, bacteria 7, for the second. He also furnishes the mean for the different months. The micrococci are pretty con- stant, the bacilli highest in April, May, July, and August, and lowest in November, January, and June; the bacteria nil in January, February, and June, and highest in the month of May. On Micro-organisms from Ice, dc. By Dr. Maddox. 455 The difficulty is to find a suitable medium for nourishing or rejuvenating all the aerial germs that have been gathered by the aspirator. The great extremes of heat and cold to which the spores of many of the Schizophytes have been exposed without loss of vitality is a point of much interest. The Rey. Mr. Dallinger, in his careful experiments, found the death-points in dry heat, for the mature monads that he had studied, to range from 138° F. to 142° F., but their spores supported for five to ten minutes 250° to 300° F.; whilst the same heated in fluid were destroyed at 212° to 268° F. M. Van Tieghem found some micrococci and bacilli to flourish at 74° C. M. Miquel cultivated one form from the Seine at 70° C., which died when the temperature was raised to 72° C. Professor Frisch finds that the bacteria seen in diphtheritic exudation and in puerperal fever resist a minus temperature of 87°5° C. without destruction, and the bacilli spores to resist extremes of cold better than the rods. M. Miquel states that a particular Bacteriwm found in snow resisted a temperature of 26° to 30° C. below freezing for three hours, and for more than twenty days a mean temperature below zero of 2°5° C. The enumera- tion of such experiments might be greatly multiplied. Drs. Cohn and Mendelsohn state that it required a powerful galvanic battery current of five elements to destroy the vitality of the bacteria they experimented upon. Not to quote more largely, it seems quite incomprehensible that such minute organisms should be able to resist such extremes of temperature, and that the so-called mucous, gelatinous, albu- minoid, cellulose, or by whatever name it may pass, covering, which is permeable to fluids, should be able to defend the living contents against such extraordinary variations of heat and cold. Here, under the hand of most careful experimenters, the reasonable- ness of previous doubt must give place and credence to the senses. Can it be that the envelope that surrounds the organism normally, when subjected to dry heat, dries so entirely and rapidly as to prevent the entire loss of moisture from within, or that the encap- sulation, so to speak, is so perfect, that there is no room for the generation of high-pressure steam, and that under moist heat the coagulation is so effective that it shrinks the outer material so closely upon the contents, that steam cannot be generated except under rupture? Or can the rapid chemical changes they can effect, suffice to continue their vitality under such abnormal conditions ? We may largely theorize, though I fear only to record our ignorance, when we attempt to limit the manifestations of life by predeterminate lines, derived from the study of higher organisms, though amongst these there are some, as the Aphides, stated to 456 Transactions of the Society. resist extreme cold, and in the case of seeds and chestnuts they are said to have survived the exposure to the very low temperature of —100° C., and very lately in experiments by Messrs. de Candolle and Pictet the refrigeration was carried to — 80° C., the seeds germinating afterwards. I think experiments have also been made on hybernating animals, but I do not remember the exact temperature destructive of life. The minuteness, however, of the Bacteria almost forbids comparison with the other objects. Such details I fear must be sadly wearying to those who take no special interest in the study of these micro-organisms, and to such I offer every apology. Nevertheless, I would ask them to try and estimate carefully the value of the study of these ubiquitous objects. ‘They set up minute changes in some of the articles of our dietary as either invite or repel the organs of smell and taste. The numerous varieties found by M. Duclaux in the imperfect making of Cantal cheese, at once point to a large field of inquiry among the articles that are in our daily diet. They play a vast role as the grand scavengers in the silent destruction of lifeless forms and are thus beneficent agents; they are the companions of our life and accompany, if they do not originate, many depressing and fatal diseases, multiplying so rapidly in cases of lowered vitality of their host that they kill by their numbers, or perhaps by depriving the nutrient fiuid of part of its oxygen, though this, as pointed out by Mr. Dowdeswell in his excellent article upon Septiczemia,* seems, in the smaller forms at least, improbable. ‘The chemical changes induced by their own require- ments may furnish noxious matters detrimental to the life of the higher organism—and harmless forms under new conditions may perhaps acquire such virulent properties, that in the state of spores the minutest quantity suffices when inoculated into the connective tissue of a healthy animal, if such have not acquired previous immunity, to cause severe illness if not certain death. Their importance, as affecting, on a vast scale, the life of man and of animals, invests them at least with the symbol of respect. It is only by cultivation that we can hope to distinguish the living from the lifeless, for may we not have before us in such as are gathered from the air, some that are dead, and some of what Dr. Phipson calls “ fossil forms.” Morphologically their resem- blances may be so great that their differences are to our powers other- wise indistinguishable. Possibly some may be inert when cultivated in one fluid, and highly poisonous in another—as in living bodies. * Quart. Journ. Micr. Sci., xxii. (1882) p + M. Miquel found by the statistics of ine ae that occurred last year at Paris, that there were nine rises which closely corresponded each to a rise in the number of Schizophytes found in the air. He merely points out the interesting coincidence. On Micro-organisms from Ice, &e. By Dr. Maddox. 457 The necessity for a certain amount of the poisonous material to be introduced or acquired in the system to produce on the one hand immunity, or on the other hand fatal effects,—the alteration some undergo by exposure to air,—the re-acquirement of highly virulent properties after having had them lessened by culture, may, perhaps, point to the very variable results exhibited in contagious maladies, and malarial fevers, under similar exposures; some receiving the contagium, so to speak, at its first offer, others resisting for lengthened periods. In the case of malarial fevers there are some points that furnish material for future study. I will mention an instructive case that came under my notice many years since. In the neighbourhood of Constantinople, and especially at the Dardanelles, malaria was endemic. Asswming malarial fever to be consequent upon the introduction into the system of the Bacillus malarix of Klebs and Tomassi-Crudelli, this point for inquiry arose. A sailor had had at one of the ports in the East Indies a first and severe attack of intermittent fever, from which he speedily recovered, and remained free from any recurrence for thirteen years, although visiting various localities where such fevers were common ; yet the same night that his vessel anchored, during the day, in the Golden Horn, he was seized with a severe attack of malarial fever, which necessitated his entry into the hospital. None of the officers or crew suffered similarly, though remaining many days at anchor. Are we to suppose the germs of the former malady remained quiescent in the system for the period of thirteen years, and that a few hours in a suitable locality sufficed to set them into activity and develope a return of the ague; or was he an individual very susceptible to malaria? I scarcely think so, as he was free at other ports where the malady was common. Again, should the second attack be supposed as unrelated to the first, under the assumption that he in some way imbibed the malaria in passing the Dardanelles, and that the incubation took three or four days to develop itself, or was it that out of all the places he had visited in the course of his voyages for thirteen years, this locality was the only one to furnish the necessary conditions for a return of the original malady, he being previously in good health ? In the malignant form, in the neighbourhood of the Darda- nelles, I have known individuals die in the cold stage within sixteen hours. Had such imbibed a really toxic quantity of the malarial poison—I am expressly assuming the correctness of the Bacillus malariz theory, which Dr. Sternberg, U.S.A., finds reason to doubt —and did the organisms multiply in such a short period throughout the system or in some vital organ as to thus speedily terminate life without any reaction, under every effort that time permitted ? Mr. E. L. Moss, Staff-Surgeon R.N., found, after forty-eight 458 Transactions of the Society. hours, by ingeniously contrived experiments, organisms in the blood drawn from intermittent fever patients which he could not find in the fresh blood. It is questionable whether they were the same as the Bacillus malariz. Dr. Marchiafava contends for the correctness of the statements of Klebs and Tomassi-Crudelli, for he finds the blood of all parts of the body, in those stricken with malarial fever, to contain in the initiative or cold stage both barren and spore-bearing rods, and in the hot or fever stage, only free spores. The cyclical course of various infectious diseases is attributed by Dr. Wernich and Professor Salkowski, from their careful experi- ments, to the destruction of the micro-organisms in the living body by their own products, i.e. they are destroyed by their own excreta. What the term of life may be for the spores of these lowly forms awaits inquiry. The germs of Bacillus anthracis are said by M. Pasteur to have survived a period of twelve years, but how much longer, lies in the investigations of the future. The medical digression has been purposely made to try and engage some of the waste microscopical energy of the members of this Society by showing that complex phenomena attributed to the action of such micro-organisms yet wait for intelligible and satisfactory answers. There is one hint I would throw out_to those who need the stimulus of patient work, viz. to follow up the researches of M. Chappuis, by watching the effect of ozone upon the life of the Schizophytes. Such an inquiry may lend light to the obscurity that now veils some of the depressing catarrhal epidemics, such as influenza, &c. Although much has already been accomplished, much has to be repeated. As yet we only touch the edge of this vast field for research. In it stands a complex problem for those to solve who have the time and patience to compete for even a fractional part. Fortunately encouragement comes from the important ex- periments now made in other countries, in the form of “ pre- ventive inoculation,” from which, already, highly beneficial results have been achieved, conservative both to life and to the pocket. May we not apply to ourselves what has been so ably said by Dr. Burdon Sanderson in his recent Lectures upon Inflammation ? “ We are all of us, old and young, too apt to forget how slow and gradual is the process by which we come to a right understanding of objective facts. Let us be prepared to give equal credit to the past and the present, accepting what is new without losing sight of, much less rejecting, what is old.” [Since the foregoing was written, that indefatigable observer Dr. Koch has discovered another of the Bacteria which he, followed by Dr. Baumgarten, considers as the cause of tuberculosis—a disease On Micro-organisms from Ice, de. By Dr. Maddox. 459 which is responsible for about one-seventh, if not more, of the deaths of our population. Dare we hope that further ex- perimental research may ultimately arrive at some method of diminishing this frightful annual loss? Shall we get a clearer insight into what we term the law of heredity? Supposing infection ab utero, has it no limiting period of incubation? must all ages bend to its presence? J am not aware whether the organisms found in fowl cholera have as yet been discovered in the newly laid egg. The answer can only come from careful experimental inquiry. In it lies the hope of discovering the means of immunity, and I trust that, in spite of hasty and prejudiced legislation, such researches may yet be made in this country, as will conduce, not alone in this, but in other maladies, to the future welfare of both man and beast, so that we may say in the words of the poet :— “?Tis worth a wise man’s best of life, *Tis worth a thousand years of strife, If thou canst lessen, but by one, The countless ills beneath the sun.”’] 460 Transactions of the Society. XI.—The Relation of Aperture and Power in the Microscope (continued).* By Professor Apps, Hon. F'.R.MLS. (Read 14th June, 1882.) II.—The Rational Balance of Aperture and Power. The discussion of Part IJ. relates to one and the same matter, viz. that from all points of view which come under consideration in the use of the Microscope, a certain proportion of aperture to power is the necessary basis of perfect performance. The question we have now to consider is: whether it is possible to arrive at a more definite determination of that propor- tion than is furnished by the preceding somewhat general dis- cussion of the question of wide and narrow apertures, and in particular, whether that can be done in such a way as to establish a rational standard for the practical construction of the Microscope. So far as I know, this matter has not yet been the subject of any kind of regular discussion, though it will be admitted, I presume, by every microscopist to be one of great practical importance. I have now directed my attention to it for more than ten years, not purely from theoretical points of view only, but by means of a long series of practical trials in which I had the advantage of the co-operation of Dr. C. Zeiss, of Jena, and I propose therefore to point out here the principles which, in my opinion, furnish an approximate standard for determining the proper balance of aperture and power in the Microscope. For this, two distinct questions must be treated separately. First, the relation of aperture to power must be considered in regard to the entire Microscope and we must ascertain what amplification of the ultimate image of the Microscope is useful, or necessary, for every given aperture, and conversely, what aper- ture is required for the proper utilization of a given amplification. If the subject admits of a scientific discussion at all, it must be possible to indicate the proper relation of aperture and amplifica- tion without having regard to the particular manner in which a given amplification is obtained by the co-operation of objective and eye-piece, provided, of course, that the amplification is obtained with the best possible quality of the image. The second question is, what division of the entire power of the Microscope between the objective and ocular will fulfil the condition of a perfect image under a given amplification. This relates essentially to the practical aim of the discussion—the determination of the focal length of the objective which is required for the utilization of a given aperture. * The paper (received 11th April) is written by Professor Abbe in English. The Relation of Aperture and Power. By Prof. Abbe. 461 i. Relation of Aperture to Power in regard to the entire Microscope. . 1. The first question may be dealt with under these two heads :—(a) What are the smallest dimensions of microscopical detail which are within the reach of any given aperture ? (b) What visual angle is required for the distinct recognition of details of given dimensions? If these can be answered in a reliable manner, the first question will have been disposed of. The smallest dimensions which are within the reach of a given aperture are indicated with sufficient accuracy by taking the limit of the resolving or separating power of that aperture for periodic or regular structures, i.e. the minimum distance apart at which given elements can be delineated separately with the aperture in question. The numerical expression of that minimum distance is A i eresh ee where a denotes the numerical aperture and X the wave-length of light ; a fair average is obtained for the latter element (with observations with the eye and white light), by taking X = 0°55 w = 0°00055 mm.; i.e. the wave-length of green rays between the lines D and H, very near to the point of maximum visual intensity in the diffraction spectrum. Though this expression applies in strictness only to the visi- bility of periodic structures composed of regularly arranged elements, it may be taken as an approximate measure of delinea- ting power in general, i.e. in regard to structures of every composition. My theoretical investigations and experiments show that with objects of every shape and arrangement, the micro- scopical image will not present any indications of structure, the dimensions of which are perceptibly below the value of 6, given (for any aperture) by the above formula. Prominences of any shape on the outline of a coarser object, for example, will disappear more and more as their dimensions approach the value of 6 for the aperture in use. Isolated elements of triangular, or quadratic, or rectangular figure will look more and more alike (becoming more and more circular or elliptical in form), as they diminish in size to the value of 6.* The loss of diffracted light attendant upon the limitation of the pencils by the lens-opening, changes or obliterates those details which are beyond the limit of the resolving power. Consequently the microscopical image of an object of any composition whatever, will always be disstmdlar to the object to the same extent; and the limit of resolving power therefore indicates the limit of simalar or correct delineation generally. * I have verified these theoretical inferences, for small apertures, by many experiments, with objects of very different nature. 462 Transactions of the Society. Hence every aperture is fully utilized when the amplification of the entire Microscope is sufficient for a distinct and convenient observation of details corresponding to the value of 6. Lower amplifications would not exhaust the aperture, because indications of real structure which exist in the image, would remain hidden from the eye. Higher amplifications, on the other hand, will not promote the recognition of the objects, because all the indications of minuter scale which they might perhaps display, do not exist in the objects, but belong to the image only—they are simply modifications of the image due to the aperture in use. Such higher powers would therefore afford nothing more than an exaggeration of those features of the image which are not conformable to the real nature of the object. We have now therefore reduced the problem under consider- ation to the single question: What amplification is necessary and sufficient in order to display the 6 of every aperture, under that visual angle which is required for distinct vision ? The facts of observation which are within the reach of every microscopist, afford all necessary data for an approximate determi- nation of this amplification. The striation of an ordinary specimen of Pl. angulatum becomes visible to a very sharp-sighted eye under an amplification of 150 diameters. As the closeness of the lines is about 0°5 w (50,000 to the inch) they are thus recognized under a visual angle not much exceeding 1’ of are. But dastenct and convenient observation for an average eye will in any case require a much higher power; how much higher, will of course vary with different individuals. I am, however, sure to leave sufficient latitude for personal diversities in assigning 300 and 600 diameters as the limits of useful amplification for details of these dimensions. In observing the diatom, no one, I presume, will deny the advantage of increasing the power if it 1s below 300; and on the other hand, no one will admit any further advantage in going beyond 600, provided the observation is made with an aperture not exceeding 0:6, which shows the striz, but nothing more.* It may be inferred from this example, in accordance with many similar facts, that satisfactory observation requires that the smallest detail of the microscopical image shall be displayed under a visual angle of not less than 2' and not more than 4’, approxi- mately ; angles which correspond very nearly to the amplifications 300 and 600 for dimensions of 0°95 p. This admitted, we obtain at once the number of diameters which are required for properly utilizing any given aperture. If a dimension 6 is to be displayed under a visual angle of v minutes of * Much higher powers may of course be utilized in the observation of Pl. angulatum with objectives of wide aperture. In this case, however, the image contains indications of form upon the markings of much minuter dimensions. The Relation of Aperture and Power. By Prof. Abbe. 463 arc, the necessary amplification, N, for a distance of 250 mm. or 10 inches (1' being = 1 : 8438) is 250 v ~ 3438 | 5” and substituting for 6 its equivalent in terms of the aperture (=) a we obtain the general formula :— 250 2av ae oe or, if X is taken = 0°00055, N = 264:'5 av, By introducing into this formula v = 2' and v = 4 respectively we obtain the figures of useful amplification for a series of different apertures. as shown in Table I.—useful, that is, so far as delineating power is concerned, putting aside for the moment any question as to the dlumination of the object, which, as explained hereafter, allows of somewhat greater apertures. TABLE I. 5, N, Amplification for obtaining a Aperture, Aperture-Angle Measure of the Visual Angle of (air). least attainable Detail. ey v=! = Ie 0°05 a°7 5°50 26 53 0°10 11°5 2°75 53 106 0°15 17°2 1°83 79 159 0°20 23°0 1:37 106 212 0°25 29° 0 1:10 132 265 0°30 35°0 0:92 159 317 0°35 41°1 0°79 185 370 0°40 47°2 0°69 212 423 0°45 03'°5 0:61 238 476 0°50 60:0 0°55 264 529 0°55 66°7 0°50 291 082 0°60 (oe 0°46 317 635 0°65 81°1 0:42 344 688 0°70 88°8 0°39 370 TAX 0°75 97°3 0:37 397 794 0°80 106°3 0°34 423 846 0°85 116°4 0°32 450 899 0:90 128°3 0°31 476 952 S95) 143°6 0:29 5038 1005 1:00 180°0 0°27 529 1058 1:05 of 0:26 555 1111 1:10 0:25 582 1164 1°15 0°24 608 1217 1:20 0°23 635 1270 1°25 0°22 661 1323 1°30 0:21 688 1375 1°35 0:20 714 1428 1-40 0.19 (Ea) 1481 1:45 0°18 767 1534 1:50 0°18 793 1587 464 Transactions of the Socvety. Conversely we can obtain the aperture a, which is sufficient for the utilization of a given power of N diameters, provided a visual angle v' is required for the least detail within the reach of that aperture. This is given by the formula ) 4, ap Sees 264°5 * Table II. shows the values of a corresponding to different amplifications under the supposition of a visual angle vy = 2'; it exhibits, therefore, the maavmum aperture which can be admitted as useful for any given power under the above assumptions. The assumption of any other visual angle as necessary for distinct vision of the least detail, would change a in the inverse pro- portion of v, so that for v = 1' we should have twice the figures of a given in the second column of the table, and for v = 4’ one-half. Tas_eE II. a, N, Aperture for Amplification | @ Visual Angle of Aperture-Angle for 250 mm. the least detail, (air). De fe) 10 0:019 2°2 20 0-038 4-4 30 0°057 6°5 40 0-076 8:7 50 0-095 10:9 75 0:°142 16°3 100 0-189 21°8 150 0-284 33°0 200 0°378 44°4 250 0-473 56°95 300 0°567 Goat 350 0° 662 82-9 400 0°756 98°2 450 0°851 116°7 900 0-945 141°8 600 1:134 700 1°323 800 1°512 900 1:701 1000 1°890 i Though these figures cannot of course pretend to be more than an approximation to the actual requirements under various given conditions, yet they will indicate with sufficient accuracy the limits of useful power; in that the delineating power of any given aperture cannot be fully utilized when the number of diameters (obtained with a really good quality of the image) is much below the minimum figures of the table; and that, on the other The Relation of Aperture and Power. By Prof. Abbe. 465 hand, we shall have an empty amplification, which does not improve the representation of the objects, if the power should go much beyond the maximum figure. The salient fact suggested by the two tables is the relatively low figures of amplification which are sufficient for very wide—in particular for the widest—apertures; and, conversely, the small apertures which are sufficient for the low powers of the Microscope. I do not, of course, intend to assert that, under particular cir- cumstances and for particular purposes, much higher figures of amplification than are shown in the tables may not be very useful or even necessary ; as, for instance, for counting, measuring, draw- ing, &e. What I wish to convey is, that in the present state of the Microscope they are not required and are not even advantageous, for research, i.e. for the proper recognition of the objects. A visual angle, for the minutest elements of a microscopical image, of 2', or at all events of 4’ (which is about the eighth part of the moon’s apparent diameter), is certainly quite sufficient for distinct observation. If indications of shape or arrangement should be found in the image, which are too minute for the powers given above, they must be at any rate of minuter dimensions than the values of 6 assigned by the first table. Indications of that kind— if such there be—have no true relation to the objects, but are attributes of the image only—mere optical phenomena, dependent upon the limitation of the delineating pencils by the lens-opening. Apart from all theory and experimental demonstration in sup- port of the principles in question, the practical experience of micro- scopists has sufficiently established that there 23 a limit to the performance of the Microscope, and one depending on the aperture of the objectives in the manner pointed out above. No kind of microscopical object can possibly afford in any respect more favourable conditions for the recognition of minutest details than those very expressive (and at the same time very simple and regular) structures of the silica skeleton of diatoms. But even with this kind of object not one trustworthy observation is on record in favour of the assumption that any given aperture, be it either 0°3 or 1-40, could reach a finer detail than is assigned by the table above, whilst there are many indubitable proofs that these theoretical limits may be as closely reached as can be expected, having regard to the difficulty of a strict determination of the actual circumstances of observation. The low figures of amplification suggested above, even for the widest attainable apertures—low in face of the views of many microscopists—are an unavoidable inference from the principle under consideration. In support of this inference I may, however, appeal to the evidence of many experienced naturalists who have done valuable work in lines of research dealing with the most Ser. 2.—Vot. II. dae | 466 Transactions of the Society. minute and delicate objects, and who agree that all real increase of our knowledge, even in these branches, has been originally obtained, or at least could have been as well obtained, by powers not much exceeding 1000-1200, whatever kind of lenses may be in question. 2. I cannot, however, restrict myself to the suggestion that excess of power, in proportion to the aperture in use, is simply of no advantage for the recognition of microscopical objects, but I must go further still, and express the opinion that excessive power is, or at least may be, a positive obstacle to correct recognition, because it will unavoidably lead the observer to take mere optical pheno- mena of the images for real attributes of the objects. ‘The following considerations will justify this view. If we observe a frustule of Pl. angulatum with the small aper- ture of about 0-6, in which case one set of lines only is exhibited at once, we may obtain a well-defined image of these lines under a power of 1000 diameters, or even more, provided a relatively short focal length of the objective and a moderate eye-piece are applied, and the illumination is effected by a very narrow beam of intense light. This power apparently displays much more than a lower power of 350 or 400 diameters with the same aperture. We see the striz as broad ridges or grooves widely separated from one another, and we recognize a distinct proportion between the breadth of these apparent ridges and their interspaces, which is 1 : 1 very approxi- mately ; whilst with 300 diameters we only catch just the fact of a striation, and nothing more. In this case now, we know that all details which are given by the 1000 diameters are mere optical illusions, because we are able to control and correct the indica- tions furnished by that power with the low aperture, by the image presented by an equal power, but having an aperture of 1:2. But if it had happened that a system of wider aperture than 0°6 had not hitherto been made, microscopists would cer- tainly have believed in the existence of ridges and grooves of equal breadth on the scale of Pl. angulatum. In this example it is unquestionable that the image obtained with an aperture of 0°6 under 300 diameters is less far from the truth than the image with the same aperture under 1000 diameters. The indeterminate striation is an indication of real structure, inasmuch as there are equidistant rows of elements in the diatom, which must appear as strie as long as the elements themselves remain occult; the exhibition of these rows as determinate ridges and interspaces with a distinct relation of breadth is a positive adulteration of the image of the structure. What holds good for an aperture of 0°6 must also hold good for every larger aperture relatively. I have before me Dr. Wood- ward’s magnificent photographs of Amphiplewra pellucida, Pl. angu- The Relation of Aperture and Power. By Prof. Abbe. 467 latwm, and other diatoms, taken with the best wide-angled lenses under amplifications of about 3000 and more diameters. Now the Amphipleura of these photographs, taken with apertures of 1:2-1°3, is the true equivalent of the Pl. angulatum of 1000 diameters with only 0°6 aperture. It shows the same determinate and energetic striation with equally broad ribs and interspaces, which are always seen when the closeness of the structural elements is not far from the limit of separation for the aperture in use. Theory and experiment show that these details of the image have no relation to the real composition of the object, that they exhibit nothing more than fypical pictures of rows of elements of any shape and magnitude whatever, when their closeness approaches the value of 65 corresponding to the aper- ture. It would be contrary to all analogy to expect that in Amphipleura alone we should have real bands or ridges, and not, as in other diatoms, distinct elements of double periodic arrangement with different closeness in different directions. This admitted, the enhanced expressiveness and determinateness of the image with the higher power is just the opposite of enhanced recognition, because the eye is caught by features which are entirely foreign to the object. If I wanted to show to any one what the Microscope has really revealed of the structure of diatoms, I should request him to inspect the said photographs at a distance of three or four feet, in order to restore the smaller visual angle corresponding to an amplification of about 1000 diameters. What he is able to recognize under these circumstances are the vestiges of true structure—indefinite, perhaps, but not falsified ; what he sees move under greater visual angle is nothing but the display of dissimilarity of object and image arising from the lack of aperture. The 3000 or 4000 diameters could improve the recognition of the real structure, only if they were obtained by apertures of 3°0 or 4°0.* It is by no means otherwise with the very minute objects of entirely different lines of research. If the image of a bacterium or a very delicate flagellum is exhibited under a power of 3000 diameters with more distinctness, as regards shape and magnitude, than is possible with one of 1000, the surplus will always be a surplus of mere optical dissimilarity. The effects of excess of power in the Microscope may be illus- trated by similar facts of astronomical experience. Astronomers * The figures of the tables should not, however, be applied directly to photographic performance, but the powers indicated for each aperture should be increased in the proportion of 0°41: 0°55 (3: 4 approximately), and the aperture corresponding to a given power diminished in the same proportion. Owing to the shorter wave-length of the rays of maximum chemical intensity, the value of 6 for every aperture is proportionately smaller in photographic than in ocular observation. 212 468 Transactions of the Society. know very well that the most trustworthy power of a telescope is not the highest power which the instrument will bear, but that power which has a certain relation to the diameter of the objective. If they use a higher amplification than about 40 per inch of the diameter of the objective (i.e. 120 for a 3-inch, 400 for a 10-inch objective) they begin to detect diameters of stars which have no diameters. A very good 38-inch objective will, indeed, show more under a power of 300 than of 100, apparently ; just the same as with a very good wide-angled Microscope-lens in regard to 3000 and 1000 diameters. In fact, the 300 diameters of the 3-inch will reveal, with somewhat bright fixed stars, very neat and distinct disks which are invisible, or nearly invisible, under a power of 100. But these disks disappear at once, when the amplification of 300 is obtained with an objective of 9 inches diameter.* Astronomers are accustomed to apply much higher powers than 40 per inch for various purposes; but they do not apply them whenever they want to recognize the true shape and magnitude of their objects. It is just the same in the Microscope. The greatest possible approximation of the image toa true projection of the object is not obtained by the highest powers, but by those powers which are just capable of exhibiting to the eye the least dimensions of real structure within the reach of any given aperture. I invite the particular attention of microscopists to this subject, as it is in my opinion of great practical importance in regard to the proper use of the Microscope. For my present purpose I may confine myself to the statement that it does not belong to the rational aim of microscopical optics to enhance the amplification of the Microscope beyond those moderate figures which are sufficient for utilizing the attainable apertures; the rational aim is rather to obtain the best possible accomplishment and the most favourable conditions, for the use of these moderate amplifications. 3. So much as to the proper relation of aperture and amplifica- tion at the upper end of the scale of microscopical performance, where the question is of the largest attainable apertures and highest useful powers. In regard to the lower end of the scale, the suggestions indicated by Tables I. and II. will require some further remarks. So far as the principle is admitted on which the computation of the tables has been based, we must consider the small apertures assigned for the lower powers of the Microscope as sufficient, * The physical conditions of the phenomena in question are not the same in the telescope and in the Microscope, but yet very similar. In both cases the effects do not arise from deep oculars—as is often assumed—but depend only on the relation of the total amplification of the instrument to the aperture. The Relation of Aperture and Power. By Prof. Abbe. 469 provided a visual angle of not less than 2’ is required for the smallest detail within the reach of every aperture. An increase would be a matter of necessity only if a given observer should consider a smaller visual angle, say 1', as sufficient for distinct observation. On the other hand, it is certain that a surplus of aperture is no drawback by itself, but only in regard to certain practical points, which have been spoken of in the first part of this paper. Among these are some which argue in favour of small apertures (penetration, working-distance, insensibility of the cor- rections, &c.), and one which is in favour of increased aperture (brightness of the image). The proper function of the theoretical considerations of the foregoing paragraphs cannot therefore be to establish an absolute rule, but rather to afford a proper basis for finding a rational balance between the various requirements of the practical use of the Microscope. Regarding those in which the advantage is always on the side of the lower aperture, it will be obvious that all of them become less and less important as lower apertures and lower powers are in question. As has been pointed out in the first part, restrictions of the working distance and inconvenient sensibility of the systems (unsteadiness of the corrections for different thicknesses of the covering glass, &c.) are not met with as long as the aperture does not exceed 0°25 (about 30°) and even with somewhat greater apertures, up to 0°5, they do not occur in any very obnoxious degree. The third element, the penetration of the Microscope, has been more fully discussed on another occasion,* where it was shown that with decreasing amplification the actual penetration, i.e. the depth which is accessible to the eye with one focussing, is more and more the result of the accommodative faculty of the eye and more and more independent therefore of the aperture. With very low powers, not much exceeding 50 diameters, a normal eye has a perceptible amount of depth of vision without any regard to the aperture. The lower the power, therefore, the more liberty is left for increasing the aperture in proportion to the power without: any perceptible disadvantage in respect to the various points above mentioned. There is, as I have said, one element in the performance of the Microscope in which a surplus of aperture will be a benefit, viz. the illuminating power, or the brightness of the image. It would, however, be a great mistake to expect that this should be without any limits or conditions, as the following considerations will show :— So far as the illumination of the objects by transmitted light is effected with light of a given intensity, and the illuminating pencils utilize the whole aperture of the objective, the brightness * See this Journal, i. (1881) p. 689. 470 Transactions of the Society. of the microscopical image depends solely on the diameter of the pencils at their emergence from the ocular, and is in the direct proportion to the square of that diameter. This diameter (d) is strictly expressed by the simple formula d=20-5 (ord = 275); if N denotes the amplification of the ultimate image for a distance of vision = J, and a the numerical aperture of the system. If we have a narrower illuminating pencil, which does not fill the whole opening of the system, the numerical aperture corresponding to the angle of the illuminating pencil must be substituted for a, instead of the full numerical aperture of the system. The diameter of the emergent pencils, and consequently the illuminating power, is entirely independent of the particular composition of the Microscope (objective, ocular, and length of the tube), and is solely determined by the aperture and the total amplification (the accidental losses of light by reflection and absorption being: dis- regarded). By giving values to / and = we obtain from the above formula the diameter d in millimetres. Under the assumptions made in the computation of the figures of the second column of Table IT. (i.e. % = 0°55 w and v = 2') we have a constant ratio of a: N, viz.:— a 1 : N ~2(264°5)’ and taking 7 = 250 mm. and substituting those values in the above formula we have A 90 = eae = 0°95 mm., consequently the same diameter d for all powers, and always the same brightness of the image therefore, provided the different _ apertures are fully utilized by the incident illuminating pencils. By increasing the values of a assigned for every power N by Table II. we enlarge the diameter of the emergent pencils in the same proportion; we should, for example, have d = 1:9 mm. throughout, if the apertures—so far as this is. possible—were in- creased in the ratio of 1 : 2, which would correspond to the assump- tion of a visual angle » = I’ for the least accessible detail. It is obvious, however, that larger apertures can be of advantage only so long as the value of d does not exceed the diameter of the pupil of the eye under the actual conditions of microscopical observation; for if this should happen, the iris of the observer must stop-off the marginal part of the lens-opening exactly in the same way as if a diaphragm were placed on the objective. The Relation of Aperture and Power. By Prof. Abbe. 471 Moreover, in microscopical observation—except under very faint illumination—the iris of a sound eye always contracts to a rela- tively narrow diameter, generally not more than 2 to 2°5 mm. Whilst, therefore, so far as delineating power alone is concerned, the largest useful aperture (for v = 2' as in Tables I. and IL.) is a 1 N N 2 (264-5) * ” = 529° plification of the Microscope will be given by the general formula above, if d is taken = 2°5. We then obtain, from a = d a the maaimum aperture for every am- N N a= 29" 500 ~ 200) and conversely N = 200.a as the minimum power required to enable the eye to admit all rays which emerge from the ocular. An aperture of 0°5 (60°) will therefore be useless in every respect (in regard to light as well as delineating power) as long as it is applied with powers of less than 100 diameters, and the same will be the case with an aperture of 0°25 (29°) for all powers below 50 diameters. Moreover, proper utilization of the rays which are admitted through a given aperture, will require still further restriction. For if the diameter of the pencils at their emergence from the ocular should closely approach the pupils’ diameter the least motion of the eye will cause a stopping-off of this or that portion of the aper- ture. The observer will therefore seldom utilize the full pencil, and will have the awkward sensation of a continual change of the illumination of the image. All this considered, it must be concluded that the wtmost amount of aperture which can be really useful under the general circumstances of microscopical work, will be, for every power, about twice the figures indicated by the second table. This corresponds to an increase of the emergent pencils to a diameter of nearly 2 mm. (1°9 mm). Every larger proportion between aper- ture and power must be considered as decidedly irrational, because it is not only waste of aperture in every respect, but at the same time a positive disadvantage for convenient and proper observation. Up to the limit here assigned, I admit the benefit of increased aperture, so far as the ower and lowest powers are in question, for which the other requirements—as has been shown—do not impose greater restrictions. In my opinion, the benefit of the increase is, however, not so much the gain of light by itself, but rather the ad- vantage, that narrower illuminating pencils, which do not fill wp the whole aperture of the objective, may be applied without incon- venient reduction of light. The smaller apertures which are sutti- cient for properly utilizing the delineating power of the objectives would also be quite sufficient in regard to light, provided the inci- 472 Transactions of the Society. dent beam always utilized the full area of the objective. In point of fact, a system of a = 0°2 (23°) applied with a power of 106 diameters will not show any want of light under that condition, even with dull daylight. The deficiency which, under all circumstances, is found in the use of high powers (notwithstanding correspondingly wider apertures) has no other cause but that we are not allowed to apply illuminating pencils as large as the full aperture of the Micro- scope. With the exception of some particular cases, the utilization of wide apertures in observing delicate objects will always require such narrower incident beams of light (generally of no greater angle than 30—40° in air) as utilize directly a small portion of the aperture- area only; the effect of the wider aperture being to collect those rays which are dissipated to large angles by the structural elements of the objects. The actual brightness of the image which is ob- tained under these circumstances is of course much less than it would be if an illuminating pencil equal to the full aperture could be employed. The proper effect of low apertures is, it is true, much less dependent upon the reduction of the illuminating beams. Nevertheless, such reduction—by means of diaphragms below the preparations—is an important benefit in many observations. or that purpose it is of practical importance that the aperture should be greater than would be required for the brightness of the image under full illumination. If twice the value of a assigned by Table II. is admitted for the several powers, these powers will still afford sufficient light, even if incident pencils of half the aperture only are used for illumination, and three-quarters of the clear area therefore is left for the utilization of dissipated rays. 4. We have now all necessary data for defining, at any rate in outline, a rational standard for the ratio between aperture and power in regard to the entire Microscope, i.e. the amplification of the ultimate image (without considering at present the participation of objective and ocular). (1.) So far as those apertures are in question which cannot at the present time be overstepped, the aim must be to obtain the most perfect performance for those powers which are just sufficient for the full utilization of the delineating capacities of these apertures. The figures of N assigned by Table I. may thus indicate the par- ticular aims for the various kinds of lenses—dry, water-immersion, homogeneous-immersion—in regard to those values of a which must be considered as the practical limits for these various systems (i.e. about 0°95 for the dry, 1°25 for the water-immersion, and 1:45 for the homogeneous-immersion systems respectively). For the full development of every system a reasonable latitude for further increase of power, beyond the limits of strictly useful powers, must, however, be left. The Relation of Aperture and Power. By Prof. Abbe. 473 (2.) So far as the medium powers are in question, which are below the limits of useful powers for the maximum apertures, but still above those amounts which could be obtained by very moderate apertures, a somewhat strict economy of aperture 1s indicated by important considerations in regard to the general demands of scientific work (penetration, working distance, &c.), because the disadvantage of superabundant aperture will be always greater than the possible benefit. For the medium powers in use, the figures of Table I. will therefore give the approximate limits of latitude which may be deemed reconcilable with a rational construction of the Microscope for scientific work. (8.) Concerning the lower and lowest powers, a gradually in- creasing latitude is left for the application of wider apertures than would be theoretically necessary in regard to the delineating capacity required for these powers. A surplus of aperture in- creasing up to about 100 per cent. for the lowest amplifications, will be in favour of the dl/wminating power of the Microscope; a considerably greater excess will at all events be mere waste.* * The concluding part of the paper—ii. Division of the Entire Power of the Microscope between Objective and Ocular—-will be printed in the next number of the Journal, 474. Transactions of the Society. XII.—Description of a Simple Plan of Imbedding Tissues, for Microtome Cutting, in Semi-pulped Unglazed Printwng Paper. By B. Wiis Ricnarpson, F.R.C.S.1., Vice- President University of Dublin Biological Association. (Read 10th May, 1882.) I am emboldened to publish the following description of a method for imbedding tissues of suitable consistence for microtome cutting, as it may have some claim to originality, imbeddmg in semi-pulped paper being unnoticed in any of the standard works on microscopic manipulation which I have had opportunities of searching. Be this as it may, very thin and perfect sections can be cut with rapidity in semi-pulped paper, from either animal or vegetable structures of sufficient firmness to remain uninjured while being sent home in the microtome well. I think, however, that im- bedding in semi-pulped paper will probably be found to have a more extended range of usefulness for vegetable section-cutting rather than for cutting animal structures. Although tissues submitted to the process should have a certain amount of firmness, as I have just observed, they should not, on the other hand, be so dense as to offer much resistance to the knife, very unresisting structures being unsuitable for this mode of imbedding. The diameter of the tissue to be cut should, when feasible, be one-quarter of an inch less than the diameter of the microtome well. Indeed, a microscopist’s laboratory ought to be provided ~ with microtomes haying wells of different diameters that both time and tissues may be economized. Stems of plants previous to cutting may, with advantage, be stored in methylated spirit for a few weeks; and animal structures, in whatever fluid has been found most appropriate for their pre- servation and, if necessary, for their hardening. I shall now give the steps of this easy method :— Cut strips, eight to nine inches long, from white unglazed printing-paper, the width of each strip to be a little more than the length of the structure to be imbedded. ‘Transfer the latter from the preservative fluid to filtered water, in which leave it for about half an hour, then dip one of the strips of paper in the water for a few seconds, remove it and drain the water rapidly off its surfaces. Take the structure to be cut out of the water, apply one end of the wetted paper to a portion of its circumference, and roll the paper around the structure as closely as the paper will allow of without tearing. If necessary, apply more wetted paper until both the paper and inclosure form a plug that should require a little Simple Plan of Imbedding Tissues. By Dr. Richardson. 475 pressure for sending it home in the microtome well. If too much paper has been applied, tear off the superfluous portion until the desired calibre is attained. The paper when wetted will, of course, stretch, but a little practice soon teaches the operator to roll it with only the tightness necessary for allowing the imbedded tissue to be cut without break. In careful hands dozens of perfect sections may be cut in half an hour from very delicate stems } of an inch in diameter, or from the delicate aereal-roots of certain orchids. But I should mention that a pine-apple stem of an inch in diameter has afforded me most perfect sections when imbedded in the semi-pulped paper. Up to the present time (April 1882) the only animal structures I have had leisure to imbed and cut in semi-pulped paper were decalcified human teeth, and a diseased external iliac artery removed from the body of a child, one of whose lower extremities I removed by amputation at the hip in March 1879. From the “dentinal cartilage” I obtained several thin and instructive specimens. The artery did not bear the knife to my satisfaction, having partially “rotted” from a too prolonged immersion in Miller's fluid. Further experience of pulped paper as an imbedding medium may lead to an extended use of the paper for animal-tissue section- cutting. But I prefer to conclude here, at all events, with a stronger recommendation in favour of pulped paper for supporting vegetable tissues in the well of the microtome under the restric- tions I have mentioned. It is almost superfluous to add that each section should be floated off the knife in water, and that a little of the latter should be carried by the blade to the semi-pulped paper in the well, to maintain it at the requisite degree of saturation for efficient cutting. The advantages which I consider the method to possess are :— (1) Facility in application ; (2) almost unlimited application in vegetable section-cutting under the restrictions above mentioned ; (3) rapidity in cutting; (4) the tissues are equally supported ; (5) cleanliness; (6) heat not being used, the subsequent staining of sections is more equal. 476 Transactions of the Society. XIII.— Note on the Rev. G. L. Mills’ Paper on Diatoms in Peruvian Guano. By F. Krrtoy, Hon. F.R.MS. (Read 14th June, 1882.) Tn the last volume of the Journal, p. 865, Mr. Mills has figured and described a new species of Auliscus, A. constellatus. After reading his description and carefully examining his excellent figures, I was satisfied that his species was identical with that described by Herr Janisch in his ‘ Zur Charakteristik des Guanos,’ Breslau, 1861-62, as A. Stockhardtiz; it is also figured in Schmidt’s ‘ Atlas der Diatomaceen-Kunde,’ Tafel xii. figs. 11-13. Schmidt remarks that fig 13 = “A. racemosus Ralfs (Gre- ville Monograph of the Genus Auliscus, T.M.S. vol. xi. 1863, p. 46, pl. iii. fig. 18) doch Janisch’s Benennung ist alter.” This is undoubtedly correct, and Ralfs’ specific name must be deleted. I communicated the result of my examination to Mr. Mills, who at once admitted the correctness of my views, and, moreover, had the kindness not only to send me the specimens of his sup- posed new species, but also most generously gave me his specimen of Aulacodiscus Kittont with fourteen processes. On examining this I congratulated myself on possessing a probably unique but certainly a very beautiful state of this species. Zxamining it again a few days afterwards, I found, in consequence of the balsam being still soft, that a valve of Aulacodiscus Comber had partially shipped over it. I resolved upon remounting it, and succeeded in placing it on another slide; during the process I caught a glimpse of the f.v., which induced me to examine it again very carefully with a binocular and + objective, when to my disappointment I found that our supposed fourteen processed A. Kzttone was composed of the two inner valves (each with seven processes) of a double frustule ; these were in close proximity—in fact, the two convex surfaces touched each other, the elevations on one surface fitting into the concayities of the other, thus accounting for the fact, noticed by Mr. Lewis, that the processes appeared “all in the same plane, and all equally and distinctly defined.” The number of processes in Aulacodiscus and Ewpodiscus are now generally admitted to be of no specific value, but it is more constant in some species than in others, e.g. A. formosus. I have never seen more than four processes, and on some valves I have observed as few as three, but in every case they were abnormal forms. In all other species the number is more or less variable. In a pure and recent gathering of A. Kittons I have seen no valve with more than six processes, four being the usual number, but abnormal forms are by no means rare. I have seen a six-rayed valve with four of the rays at right angles to each other, Diatoms in Peruvian Guano. By F. Kitton. 477 the remaining two being close to the opposite rays (processes). The most remarkable abnormally is a valve without process or avra€, but with the former faintly indicated near the margin. It is only right to add that these remarks on Mr. Mills’ paper have been written at his request, as he does not wish an error to remain uncorrected. 478 SUMMARY OF CURRENT RESEARCHES RELATING TO SUMMARY OF CURRENT RESEARCHES RELATING TO ZOOLOGY AND: BO] snes (principally Invertebrata and Cryptogamia), MICROSCOPY, &c., INCLUDING ORIGINAL COMMUNICATIONS FROM FELLOWS AND OTHERS.* ZOOLOGY. A. GENERAL, including Embryology and Histology of the Vertebrata. Division of Embryonic Cells in the Vertebrata.t—L. F. Henné- guy, in studying cell-division as exhibited in the ovum of osseous fishes, finds that that of the trout, on the third or fourth day after fecundation, if treated with a mixture of acetic and picric acids, is the best adapted for this investigation; the cells are then seen to be formed of a finely granular protoplasm, and contain a nucleus of some size. The nucleus of acell in a state of repose contains a plexus, formed of small irregular granulations, which are especially well stained by carmine. The nucleolus is only a little larger than the other granu- lations. Soon there appears around a clear space, of which the centre is occupied by the nucleus, very fine clear lines, which are set along the rays of the cell, and which together form an aster; this aster elongates and becomes elliptical, as does also the nucleus; the aster then divides, and the two halves each form a fresh aster; at this moment the membrane of the nucleus disappears, and the rays of the aster penetrate into the interior. The plexus now breaks up into a number of small rod-shaped bodies ; these become set at the extremities of the rays, and form the so-called equatorial plate. Gradually the rods diminish in size but increase in number, and fuse to form a pectinate figure. The body of the cell then begins to be constricted in its middle, the rays of the aster disappear, and the connective filaments alone remain to unite the two nuclei, until at last the cells become completely separate. The new nucleus, due to the fusion of the rods, is highly refractive, and is intensely coloured by reagents ; * The Society are not to be considered responsible for the views of the authors of the papers referred to, nor for the manner in which those views may be expressed, the main object of this part of the Journal being to present a summary of the papers as actually published, so as to provide the Fellows with a guide to the additions made from time to time to the Library. Objections and corrections should therefore, for the most part, be addressed to the authors. (The Society are not intended to be denoted by the editorial ‘‘ we.”) + Rey. Internat. Sci. Biol., ix. (1882) pp. 363-5, ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 479 as it increases in size, there appear the limiting membrane and the internal plexus. At a later stage of development, when there has been multiplica- tion of the cells, these become smaller and smaller, and the asters gradually become quite indistinct. In the earliest stages of segmen- tation the process of division is more difficult to follow, owing to the large size and very granular contents of the cells; on the first and second day the cells become so uniformly tinted that the nuclei are with difficulty made out. As the cells diminish in size the action of the colouring matter becomes more and more confined to the nucleus, and the author is of opinion that the chromatin of Flemming is at first uniformly distributed through the cell, and that it gradually separates to form a constituent of the nucleus. Genesis of the Egg in Triton.*—Mr. T. Iwakawa records the result of observations on the genesis of the egg of the common Triton (T. pyrrhogaster Boje), in which he describes the manner of depositing the egg (the female turning upside down so as to place it under the leaf or stem), the structure of the ovary, origin of the ovum and Waldeyer’s “epithelial islands” (the author’s view being that the ovum does have an epithelial origin), the formation of yolk- spherules, the vitelline membrane, the germinal vesicle, and the “ yolk- nucleus.” Formation of Fibrine.t|—In 1879 Dr. Norris described the alleged discovery of a third corpuscular element in blood in the form of colourless disks, which he considered to be an earlier stage of the red corpuscles. { This was criticised by Mrs. Ernest Hart in the fol- lowing year, § her view being that they were red corpuscles that had undergone post-mortem changes prior to taking part in the formation of fibrine. Continuing her investigations and repeating the experiment of “isolation ” || a great number of times, she began to observe that the appearances changed according to the length of time which elapsed between the spreading of the layer of blood between the two glass surfaces and the moment when the cover-glass was raised, and thus discovered that a whole series of phenomena could be traced, leading from the pale or colourless corpuscle up to the complete formation of networks or bands of fibrine. In developing this method of working it was found that the staining reagents recommended by Dr. Norris were not sufiiciently powerful to bring out all the details that could be observed on the glass surfaces, and after many trials a highly con- centrated solution of nitrate of rosanilin in absolute alcohol was found to be the best staining reagent. The method adopted was to detach the cover-glass from the slide after the corpuscles had been fixed by osmic acid vapour, and to examine both the surfaces of the cover-glass and the slide, to see which presented the most perfect preparations. * Quart. Journ. Micr. Sci., xxii. (1882) pp. 260-77. + Ibid., pp. 255-9 (1 pl.). t See this Journal, iii. (1881) pp. 229-32. § Loc. cit. || See description, loc. cit. 480 SUMMARY OF CURRENT RESEARCHES RELATING TO Having made a selection, a drop of the concentrated solution of nitrate of rosanilin was deposited on the glass and allowed to remain for a few moments, and then washed off with a fine jet of distilled water. The red, pale and colourless corpuscles, with their ramifications and the most delicate fibrils of fibrine, then become visible under a high power. The preparations may be mounted dry, and will keep for a great length of time. If the process be performed as rapidly as the dexterity gained by an oft-repeated experiment will allow, it will be observed that the circular appearance of the corpuscles is perfectly preserved, and that every shade of colour may be found, from the normal red corpuscles down to the colourless Norris corpuscle, which only takes the faintest tint of pink. If, however, the glass surfaces be allowed to remain in contact for a moment, the colourless cor- puscles are found to have lost their globular form, and to have become pyriform or elongated. On leaving the glass surfaces still longer in contact, these pale corpuscles are observed to undergo a remarkable change. They send out long processes or tails, which bifurcate and divaricate in every direction. On allowing a still longer interval to elapse, so that itis more than probable that coagulation would occur in a film of blood lying between two glass surfaces, and on separating these surfaces, perfect specimens of fibrine may be obtained after staining. On now searching the field, the pale corpuscles, which could formerly almost always be discovered, are nowhere to be found, and the conclusion is forced upon one that the branching corpuscles have developed or broken down in fibrinous threads. Small granules are, however, found from which threads of fibrine appear to spring. These granules are described in Ranvier’s ‘Traité Technique d’Histologie’ as the centres of fibrine formation. They appear to the author to be all that is left of the pale corpuscles, whose intermediate transformations have not before been recognized, but may perhaps be identified with the appearances and changes described. Amongst other figures, one is given showing the departure of the fibrils of fibrine from the pale corpuscles. New Blood-corpuscle.*— According to G. Bizzozero, if the circu- lating blood in the small vessels of the mesentery of chloralized rabbits or guinea-pigs is observed under a high power, there will be seen, besides the ordinary red and white cells, a third form of cor- puscle which is colourless, round or oval, and from one-half to one- third the size of the red corpuscle. He considers that they have hitherto escaped the notice of observers (1) owing to their translucency and want of colour; (2) because they are less numerous than the red, and less visible than the white corpuscles ; (3) owing to the great difficulty of observing the circulating blood in the small vessels of the warm-blooded animals. They can be seen also in freshly drawn blood, for the most part aggregated around the white corpuscles, or immediately under the cover-glass, to which they adhere. They soon become granular, and give rise to what is called the granule- masses. ‘Through appropriate reagents their form can be preserved. * Arch, Ital.de Biol., i,(1882) pp. 1-4; cf.‘ The Microscope,’ ii. (1882) pp. 59-60. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 481 A solution of salt coloured with methyl-violet has this property. The best method of examining them in the human subject is to place a drop of the above coloured solution over the puncture and mix the drop of blood thoroughly with it. Owing to their typical forms, it is very unlikely that they are derived from the red corpuscles. The colourless corpuscles contain no ingredients from which they could be derived. After bleeding, and in many diseased conditions, they are increased in numbers. They play an important part in the formation of thrombi and the coagula- tion of the blood, which has been attributed by Mantegazza and Schmidt to the white corpuscles, because the latter are few in number in the circulating blood, and their destruction was never observed by Bizzozero, provided the blood was mixed with a saline solution, Again, the time at which coagulation sets in corresponds very closely to the time that these new corpuscles undergo degeneration. The fluids which retard or prevent coagulation—as solutions of carbonate of soda and sulphate of magnesia—have the same action in pre- venting the granular degeneration of these corpuscles. An indif- ferent solution of salt does not preserve them, but one to which the methyl-violet has been added does. From this evidence it appears (to the editor of the ‘ Cincinnati Medical News’) highly probable that the formation of fibrine takes place under the direct influence of these corpuscles. To them Bizzo- zero gives the name of “ Blutplattchen.” Life and Death in the Animal Organism.*—After completing an important investigation on the “ Earliest developmental operations in the ovum, on cell-division, and on conjugation in the Infusoria,” O. Biitschli, early in 1876, wrote an essay headed “ Thoughts on Life and Death,” but he left it unpublished, considering, on the one hand, that his ideas on the differences between Protozoa and Metazoa in respect of the phenomena of death were too recently acquired to be made known, especially in print, and that, on the other hand, the speculations which he had associated with these ideas were too immature to be made permanent. His fundamental views, however, namely those relating to the non-existence of individual death in the Protozoa, have now been published. “Tf we glance over the phenomena of the origin and destruction of beings in the great series of animal organisms, we are astonished by a significant contrast in the importance of individuality in the higher, i.e. the many-celled, as compared with the lower, i.e. the uni- cellular, forms, the Infusoria or Rhizopoda. Whilst in the first the individual, in almost all cases, asserts an existence definite and distinct even from its progeny, in the unicellular forms, on the contrary, which reproduce by fission, we are met with the fact (which does not usually receive much attention) that at the time of reproduction the individual, as such, ceases to exist, and divides its individuality equally between the individualities of its two offspring, which now come into existence. This remarkable phenomenon * Zool. Anzeig., v. (1882) pp. 64-7. Cf. Naturforscher, xv. (1882) pp. 125-6, Ser, 2.—Vor. II. 2K 482 SUMMARY OF CURRENT RESEARCHES RELATING TO appears in the most striking light when we endeavour to realize in these lower forms the idea of death, such as we have been led to consider it from observations of the higher animals. Death in the higher organisms is not the total extinction of life, but only of the individual existence; bat the reproduction of a unicellular organism constitutes at the same time its death. On the other hand, however, by the idea of death in the higher organisms is implied an actual separa- tion of organized substance from the activity of life, in other words, an annihilation of previous life. This element is entirely wanting in the individual death of the Protozoa, that is, in its reproduction ; it goes on living all the same, though in the persons of its progeny. If we study the development of certain Protozoa,—the Infusoria,- — we come upon the highly remarkable fact that death does not occur in them, in the sense of annihilation of organic material and from causes inherent in the organism itself. Although these organisms, in the course of their life, are threatened by death under a thousand forms, yet this takes place by “accidents,” and thus the few individuals which reproduce the species are to be considered of equal importance with the multitude which perish, for the few reproduce by fission only, and are thus immortal; while the many which die could have repro- duced their species just as well as the others, if they had had the same favourable opportunity; not one of them necessarily carries in it the seeds of death. Whoever wishes to construct a hypothetical representation of the fact that in the higher animals the individual is limited in its dura- tion to a certain time, will find a tolerably simple plan open to him. If we hold it to be allowable to consider the peculiar vital manifesta- tions of the cell, the fundamental element of every form of organiza- tion, as caused by the presence of a substance which acts in a certain sense like a ferment,—necessary to the production of those chemical changes in the cell which result in vital manifestations, but gradually, though perhaps slowly, used up,—then the limited duration of the life of one of the higher animals may be intelligibly represented by assuming that the ovum out of which this organism once originated acquired a certain amount of this ferment-like substance, which is gradually exhausted during life, and with the final exhaustion of which the end of the individual existence coincides. It is otherwise with the Protozoa, which reproduce by simple division. These organisms have also this characteristic vital ferment, but they also enjoy the peculiarity of being able to renew it ; hence it is not exhausted in them, and they are not overcome by death in con- sequence of its being used up. But the power of forming this vital ferment is shared by the higher organisms as well, but here it is localized, being confined to the generative organs. In the other cells composing the body the material we have been speaking of is gradually and increasingly used up in the course of their active existence; but in the generative regions, whose cells maintain their primitive character longest, fresh vital ferment is accumulated for their posterity. Certain appearances occur which, perhaps, justify us in forming an approximate idea as ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 483 ' to the place in the cell which this material with its property of evoking life occupies. Among these the chief are the phenomena of conjugation of Infusoria, taken in connection with facts recently acquired in the study of the process of fertilization in the Metazoa. The gradually diminishing vital energies of the Infusoria are strengthened afresh by conjugation, and this comes about by a partial or total renewal of the nucleus from the so-called nucleoli or primary nuclei. A total or partial renewal of the nucleus of the ovum is also seen in fertilization, and it is most probably effected by the spermatic nucleus. (This passage was written in 1876, when the first and imperfect account of the process of fertilization had just been put forth; but it would be easy to alter it so as to bring it into accordance with our present knowledge, without interfering with the part played by the nucleus.) Thus the failing vital powers of the Infusoria are raised up again by the renewal of the nucleus, and a similar result occurs in the process of fertilization; is it not, therefore, a justifiable conclusion that the vital ferment which has been spoken of, actually resides in the nucleus of the cell, whenever this is present. It is not the whole nucleus which is to be interpreted in this way, but only a small part of its bulk. Thus in the case of the Infusoria, it must be assumed that the freshly produced life-ferment is collected more especially in the so-called nucleoli, but in higher organisms in the reproductive cells, chiefly in the nucleus of the male reproductive elements.” N. Cholodkowsky, in discussing * the doctrine of Biitschli, points out certain difficulties in the way of our accepting this view. Some forms, e.g. Hydra, have an asexual as well as a sexual method of reproduction ; now, if all the cells of such an animal have the power of producing new individuals they must all be immortal; yet, as a matter of fact, we know that many die down. It seems to Cholod- kowsky that the cause of the death of the Metazoa is to be sought for in the multicellularity of their organism. A cell has in itself and for itself a potential immortality; but as soon as differentiated cells are united into an individual there commences amongst them a struggle for existence, which, eo ipso, leads to destruction. The hypothesis of Butschli recalls the Darwinian doctrine of Pangenesis ; just as Darwin supposed a general distribution of reproductive cells throughout the organism, which only later became concentrated in the generative cells, so does Butschli deal with his vital ferment, and the doctrine of the latter is therefore only a more physiological way of expressing that of Pangenesis. Pelagic and Deep-Sea Fauna.jf—T. Fuchs enumerates the distinguishing characteristics of the pelagic and the deep faunas respectively, and makes some inductions as to the reasons for these peculiarities. Pelagic animals are those which are wholly indepen- dent of the shore and the sea-bottom at all stages of their existence. * Zool. Anzeig., v. (1882) pp. 264-5. ‘ + Verh. k. k. Geol. Reichsanstalt, 1882, pp.49 and 55. Cf. Naturforscher, xv, (1882) pp. 199-202. ae 2 484 SUMMARY OF CURRENT RESEARCHES RELATING TO Most of them are transparent and colourless, and thus invisible in water; where colour occurs, it is usually violet or blue, resembling that of the water; the fishes are chiefly stcel-blue above, silvery-white below. Most forms are naked; the shell, if present, is comparatively delicate. A large number are viviparous, even when their nearest allies are oviparous. A great number of pelagic animals are phosphorescent. Nearly all are admirable swimmers. Some have their surface-area largely developed, e. g. the tests of Radiolaria, of Globigerina, Hastigerina, &c., probably in order to hinder sinking. As to the manner of life, they are almost without exception social, they mostly have a very wide distribution, and are found alike in the Atlantic, Indian, and Pacific Oceans; the genera are almost all identical in these seas, although polar seas are distinguished from warmer waters by possessing few forms besides Crustacea, Pteropoda, Cephalopoda, and Cetacea. In connection with their usually delicate structure stands the fact that it is only in the calmest weather that they live on the surface; storms may drive them to a depth of more than 50 fathoms. Further, far the majority only come to the surface in the night, a point to be con- sidered in connection with the prevalence among them of phosphor- escence; the time of appearance of the phosphorescent fish is more often connected with the night than with any other time. Pelagic animals seldom occur except over deep water, and at great distances from coasts, hence their scarcity in the German Ocean, their poverty in littoral and their abundance in deep-sea deposits. The deep-sea fauna is distinguished by the appearance or pre- dominance of certain individual species, genera, and families, and exhibits little variation in the different parts of the world. It com- mences at a depth of about 50 fathoms in all seas, but it is only in the tropics that anything like a sharp line of demarcation is found between it and the littoralfauna. Examining these points to ascertain the reason for a bathymetric limit of this particular nature, Fuchs finds that it cannot be due to temperature, although this diminishes as the depth increases, for in the Red Sea the warm zone extends much below 50 fathoms, while in polar waters even the surface has a low temperature, and currents operate besides so as to introduce great irregularity into the bathymetric relations of temperature ; however, the fact that 48 to 50 fathoms has been ascertained to be the limit to the penetration of light into the sea appears to him good evidence that the presence or absence of light is the determining agency sought for, and that the littoral fauna is simply the fauna of the light, the deep-sea fauna that of darkness. ‘This view is supported by the more superficial distribution of deep-sea forms in some places in which the limit of light lies at an inferior depth, and the deeper range of littoral forms in fresh waters, where the light has greater penetration. The large eyes or blindness of so many, the pale or monochromatic colour of most, and the phosphorescence of a large number of the animals which compose this fauna is evidently connected with the absence of light. The resemblance of the pelagic to this fauna is intelligible if it is remembered that it too is most in its element in ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 485 the darkness. Resemblances between cave faunas and that of the deep-sea point also to a common cause in the absence of light. The range of some littoral forms into great depths may perhaps be found to be due to their being nocturnal in habits. The cavities which occur under coral reefs off Brazil may perhaps shelter a fauna of deep-sea character, owing to the absence of light there; hence it would be not unlikely that geologists might find similar aggregations of deep-sea animals in formations otherwise composed of littoral reefs. Otherwise the relations of deep and littoral faunas were probably much the same in geological times as now, owing to the similarity of their relations to the light, and the differences here indicated can, in point of fact, be traced throughout all formations. B. INVERTEBRATA. Mollusca. Anatomy and Classification of the Cephalopoda.* — Dr. J. Brock commences with a study of Rossia, the knowledge of the anatomy of which is confined to the short description given by Prof. Owen. Asa result of the new investigations we find that Rossia is, as has been supposed, most closely allied to Sepiola ; the relations of these two forms to the Myopsida, and especially Sepia and Loligo, are by no means so clear. The author’s earlier investigations led him to the belief that the affinities of the different forms might be well shown by this diagram :— Sepia. —Rossia——_——Sepiola. —Loligo. —Ommastrephes, The presence, however, in Rossia, of fused lower salivary glands points to its affinities with the Cigopsida, and this would lead us to form a table in which Loligo should stand above Rossia, or nearer Sepia. As to the relations of Sepiola to the form last named, it might be supposed that Sepiola had branched off from the Decapod stem independently, but the Octopod characteristics of Sepiola, as seen in its musculature, are to be found also in Rossia, and it requires evidence of a kind very different from that which we have at present to lead us to believe that these very similar arrangements could have been independently developed by the two forms. The Octopod type of the musculature of Rossia is still further developed in Sepiola, and that in a way which justifies us in regarding the latter as a direct descendant of the former. A useful table is given in which are enumerated twelve characters and the respective resemblances and differences of Ommastrephes, Rossia, and Sepiola. If the view that Rossia and Sepiola form a line of development which branched off from the Decapod stem shortly before Loligo be * Zeitschy. f. wiss. Zool., xxxvi. (1882) pp. 543-640 (4 pls.). 486 SUMMARY OF CURRENT RESEARCHES RELATING TO correct, we find in it what may be spoken of as parallel-developments ~ with the Myopsida and Octopoda; we find, that is, in this side branch a series of differentiations which have, for the different organs, _ a most remarkable resemblance in those two series. Just as from Loligo to Sepia, so from Rossia to Sepiola we find the upper salivary glands lost, the accessory nidamental glands fused, the efferent duct of the ink-bag sharply marked off, and the lateral teeth disappearing from the middle plate of the radula. From Ommastrephes to Sepia, just as from Rossia to Sepiola, the fused lower salivary glands are separated, and there appears a characteristic arrangement. of the ova in the duct. Likewise, there is in Sepia and Rossia a shortening of the inner pallial nerves, which finds its termination in the absence of these in Sepiola on the one hand, and the Octopoda on the other. A very instructive diagrammatic table is given by the author to demonstrate the points on which he insists. If we enter into still wider generalizations, the facts observed by the author lead us to see that in the Dibranchiate Cephalopoda, long before the separation of the phylum into the Octopoda and Decapoda, there must have been a tendency, under suitable, though still un- known, conditions, for the cartilaginous articulations with the mantle and funnel to yield to firmer membranous or muscular cephalic joints ; thrice, or twice at least, did this tendency exert its influence. In connection with this there must also have been a tendency to the reduction and final loss of the upper salivary glands, the separation of the lower ones, and the fusion of the accessory nidamental glands. Dr. Brock then passes to a second study of the generative organs of the Cephalopoda; in dealing with the female organs of the Cigopsida it is pointed out that the nidamental glands may be absent, as in Enoploteuthis, or that they may be present, with (a) the oviduct lying ventrally to the gills, as in Ommastrephes sagittatus, or (6) the oviduct may open with a buccal invagination of the integument, lying dorsally to the gills, as in Om. todarus, Onychoteuthis, or Thysano- teuthis. A study of the generative organs of the Philonexide shows, us that they may be thus arranged :— 1. Subfam. Hectocotylifera. ¢ with a free Hectocotylus. a. Philonexide S. Str. Hectocotylus without dermal frills. No water-vascular system—Argonauta, Philonexis. b. Tremoctopodide. Hectocotylus with dermal frills. A water-vascular system—Tremoctopus. 2. Subfam. Parasiride. Free hectocotylus not known, but pro- bably present. @ with very long oviducts, viviparous. Parasira. - In dealing with the gland of the oviduct, it is pointed out that — the following series may be detected in the Octopoda :— 1. Gland consisting of a series of ceca arranged radially around the oviduct; no increase in the extent of the secreting surfaces —Argonauta. 2. The secreting surfaces of the gland well developed, and a ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 487 circlet of strongly developed receptacula seminis interpolated between the gland and the oviduct—Tremoctopus violaceus. 3. The receptacula seminis not so well developed; a fresh gland developed between them and the primitive gland—Parasira catenu- lata. 4, No receptacula seminis; the walls of the primitive and of the secondary gland highly developed, and in the latter so far advanced as to lead to a fusion of the glandular sacs—Octopus, Eledone. Various as are the forms of the oviducal gland in the Octopoda it is important to notice how uniform they are in the Decapoda. The author then enters upon a consideration of the so-called water-canals and the viscero-pericardiac cavity; he finds that the genital capsule of the Octopoda is the (reduced) direct homologue of the viscero-pericardiac cavity of the Decapoda; and that the water- _ canals of the Octopoda correspond to the anterior, while the genital capsule corresponds to the hinder portion of the viscero-pericardiac cavity of the Decapoda. And he concludes with accounts of Tremoctopus ocellatus n. sp., Octopus pictus n. sp., Loligo bleekeri, and Cranchia reinhardti. Ink-Sac of Cephalopoda.*—P. Girod publishes a full and detailed account of his study of this organ.f By a careful dissection, first of the peripheral trabeculze, and then of the apex of the pyramid formed by the formative zone, we come upon the cellular mass which forms the central portion of the trabecule. When a portion of the tissue of this part is teased out, elongated cylindrical cells may be detected which, in their general character, are not unlike the cylindrical cells of many mucous membranes; the large nucleus which occupies the narrower end of the cell becomes very apparent on the addition of colouring reagents. The cell itself, on high mag- nification, is found to be divisible into two portions: the larger of these is coloured yellow by picrocarmine, and seems to be formed of a hyaline liquid, which is limited on the nuclear side by a faint, slightly concave, and granular line ; the second and narrower portion contains a granular protoplasm. The constitution of the cell sug- gested to the author that it belonged to the calyciform series, but the absence of any orifice did not seem to him to justify that view. Near these cells others may be seen which contain black granula- tions in their upper portion; these are not cylindrical, but are divided by constrictions into three portions ; the uppermost colour- ing matter is bounded externally by the cell-membrane, and is also distinctly separated from the nucleus. On the whole, there is a very close connection between these and the cells of the first set, the hyaline mass in the latter being now filled with pigmented granula- tions, and the part which contains the nucleus having been elongated. Other cells present other characters ; in some there is a much larger aggregation of pigment, whence two lateral prolongations descend, one on either side of the nucleus: here, too, slight pigmented granu- * Arch. Zool. Expér. et Gén., x. (1882) pp. 1-100 (5 pls.). t See this Journal, i. (1881) pp. 227, 586, and 876. 488 SUMMARY OF CURRENT RESEARCHES RELATING TO lations are to be seen within the substance of the nucleus. In others the black granulations are so richly developed as to completely obscure the nuclear mass, although that body is still present. Finally the cells commence to undergo degeneration, their membrane breaks, and the pigment escapes ; the nucleus, however, still persists, and it is in consequence of this that we find free nucleated masses in the midst of the pigmented granulations. The author discusses in order the histological characters of the meshwork, the wall of the pouch, its internal, median, and external tunics. Turning to the development of the ink-sac, we find that on the fourth day of the second period (that of the development of the organs) the anal depression comes in contact with a process of the mesoderm, and then divides into two portions, the superior of which is the ink-sac, and the inferior the rectum. The former rudiment has at first a transverse direction, and extends from the anal orifice to the internal yolk-sac, and is clothed by a single layer of epithelial (ecto- dermic) cells. This is what will form the vesicle. The cells at the cecal extremity soon begin to multiply and form a thickening which is the rudiment of the gland. The glandular mass developes rapidly by making its way into the midst of the mesoderm; the cells of that layer now begin to form peripheral layers around the gland, till they nearly completely surround it, and the mass becomes divided into two lobes, between which there is an extension of the mesoderm. Changes in the cells themselves now appear, and give rise to the formation of a thick granular liquid. As soon as the glandular cavities are developed the investing cells take on the characters which belong to the formative zone of the adult, and a peripheral and a formative zone are thus developed. Further changes bring about a connection between the gland and the reservoir; the latter then begins to increase rapidly in length, and at the same time to dilate. Still further changes, in the mesoderm, give rise to the different investing layers, and there is some alteration in position. Looking more generally at the matter, we find that the ink-sac is formed by an epidermal invagination, which, during development, is differentiated into two parts, the gland and the vesicle (reservoir) ; this invagination is contained in a kind of mesodermic sac, which forms the tunics that envelope the epithelium ; the innermost of these consists of an epithelial and of a connective layer, the median of the silvery and of a muscular layer, and the outer of connective tissue. When we compare this with the integument, we cannot but be struck with the remarkable similarity between them ; there, too, we find an epithelium, the cells of which are arranged in a single row, and limited externally by a thick cuticle; the connective layer contains the chromatophores, and beneath this there are a silvery layer, muscular fibres, and a layer of connective tissue. The absence of chromatophores in the region of the sac may be explained by a study of the intermediate stages presented by different parts of the body. The researches of Lacaze-Duthiers on the purple-glands of certain Gastropoda have led the author to make a study of these structures, from which it results that their anal gland is homologous with the ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 489 ink-sac of the Cephalopoda, and this view is strengthened by a consideration of the nervous supply. In the Gastropoda the glands in question receive filaments from the “‘ asymmetrical centre,” in the Cephalopoda the nerves come from the visceral or inferior ganglion which corresponds exactly with that centre. If we compare the ink-sac of the Octopoda with that of the Deca- poda we find that there is in the former an arrest of development, the reservoir not being elongated or widened out; in consequence of this close relations still obtain between it and the anal orifice, and the gland and reservoir are closely applied to one another. It is to be borne in mind that the tetrabranchiate Cephalopoda are without the organ, and that it is only some of the Gastropoda which possess one, and that that one is always much simpler in character. The physiology of the question is also dealt with, and it is pointed out that three stages may be distinguished in the excretion of the ink: (1) there is a continuous passage of ink from the gland into the vesicle—due to a vis a tergo, and to the compression exercised by the limiting membrane of the gland and the nodosity of the vesicle; (2) an intermittent passage of the ink from the vesicle into the sac, due to the contraction of the vesicle; (3) spasmodic expul- sion of the ink by the funnel, due to the spasm of expiration. The nerve-branches from the visceral nerves were found to be motor filaments, presiding over the contraction of the wall of the vesicle. Sense of Colour in Cephalopoda.t*—How highly developed the sense of colour is in insects has been shown by Sir John Lubbock in his interesting observations on bees, wasps, and ants. For the development of the same sense in animals of a different type C. Keller brings forward evidence taken from the cuttle-fishes, which manifest in a high degree the power of adapting the colour of their skin to that of the environment. Keller was able to observe this adaptation of colour in Eledone. In the Naples Aquarium a specimen of this Octopod was under the necessity of flying from a powerful lobster; during its flight it appeared pale red ; but subsequently, resting on a tuft of yellow rock covered with brown spots, it imitated the yellow ground- colour with its brown spots so closely that it became almost invisible to the observer. In this case the conditions were decidedly very favourable for the occurrence, for yellow and dark-brown colour-cells occur in Eledone in large numbers. It should be added that the eye of the cuttle-fish shows an unusually high development. ‘Foot’ of certain Terrestrial Gastropoda.t—Mr. J. Wood- Mason describes the structure of the part of the foot called by German writers on malacology the Fuss-sawm which, as no technical name for it appears to exist in the English language, he proposes to call the peripodiwm, in allusion to its relation of position to the locomotor ventral surface or foot of the molluscs possessing it, but which he thinks may be homologous with the lateral folds (epipodia) * Vierteljahresschr. Naturf. Gesell. Zurich, xxvi. (1881) p. 100. Cf. Natur- forscher, xv. (1882) p..40. + Proc. Asiatic Soc. Bengal, 1882, pp. 60-2. 490 SUMMARY OF CURRENT RESEARCHES RELATING TO of many marine molluscs (Haliotis, e. g.). Very frequently the peri- podium is provided at its posterior extremity with a capacious pit, the capacity of which may be increased by the prolongation upwards of its anterior margin in the form of a horn, which not being specially sensitive is not a tentacle, often it is without this terminal pit; it is invariably richly ciliated throughout from the mouth on one side round to the mouth again on the other side dorsally; equally in- variably is it limited off from the side of the body (and frequently also from the muscular foot) by a peripheral groove, which deepens anteriorly. Its office is to assist in lubricating the foot, the pit when present receiving the effete lubricating fluid and throwing it off in gelatinous lumps. The foot-gland, as is well known, pours out its abundantly ae constantly flowing secretion through an aperture which is situated below and a little behind the mouth into a hollow whence it naturally falls into the deep anterior end of the dorsal peripheral groove, whence again it is carried by the cilia with which the surface of the peri- podium is beset (being distributed to the foot as it goes) to the terminal pit. In those forms in which this pit does not exist, the secretion that has served for lubrication is merely left behind by the crawling mollusc. As Pulmonata possessing a ciliated peripodium with and with- out a terminal pit are to be found in every quarter of the globe, and as it is in the highest degree improbable that so highly specialized a structure, subserving such an important purpose in the animal economy as this evidently does, has arisen independently many times in many different forms in many widely separated areas of the earth’s surface, the author considers that it has a higher taxonomic value than has hitherto been assigned to it, and he feels strongly inclined to distinguish those forms that possess it and those that do not (or have lost it) from one another by calling them Craspedophora and Lipocraspeda respectively. Mucin of Helix pomatia.*—According to H. A. Landwehr, when the mucin of Helix pomatia is treated with 1 per cent. sulphuric acid, it yields grape-sugar, whereas mucin from other sources yields only a reducing substance. The grape-sugar cannot be derived from glycogen, since the iodine reaction fails entirely in the freshly expressed secretion, and in the mucin prepared from it. The author however, succeeded in obtaining a carbohydrate, for which he propeses the name “achrooglycogen.” In order to prepare it, he directs that the mucin obtained from the snails shall be treated with 5 to 10 per cent. caustic potash, and the proteids separated by Briicke’s solution (potassiomercuric iodide), the solution filtered, and the filtrate pre- cipitated by alcohol. The material thus obtained, after being washed with absolute alcohol and dried, is an amorphous, white, “tasteless powder, readily soluble in water. The solution is strongly opalescent, gives no iodine reaction, and does not reduce an alkaline copper * Zeitschr. f. Physiol. Chem., vi. (1882) pp. 74-8. Cf. Journ. Chem. Soc. Abstr., xlii. (1882) p. 708. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 491 solution. By boiling with acids, or by digestion with saliva or diastase, the substance is converted into dextrin and grape-sugar. Rhodope veranii.*—Professor L. Graff gives an account of this form, which was regarded by Schultze as a Turbellarian, and named Sidonia elegans; he has been able to demonstrate that it is not a worm, but the Nudibranch long ago described by Kélliker under the name of Rhodope veranii. The largest examples are about 4 mm. long, with a breadth of } mm. The integument consists of a single stratum of cylindrical epithe- lial cells, and is pretty closely invested by long cilia; this integument is pigmented, and a figure of the curious arrangement of the colour, under what the author regards as its typical form, is given. Cal- careous spicules, of some size, are to be found under two different forms, embedded in the parenchyma of the body. The mouth lies at the anterior end, but is sometimes held dorsally ; the cavity into which it leads is provided with closely appressed small papille, but there is no indication of anything like a radula. After some account of the other parts of the digestive system, of the nervous system, and of the generative apparatus, Dr. Graff states that, like Kélliker, he searched in vain for any indication of a heart or blood-vessels. The numerous small oval corpuscles which fill the ccelom were suspended in a colourless fluid, which appears to be set in motion by the move- ments of the body, or the contractions of the enteron. The author was, however, enabled to discover a water-vascular system similar to that of the Platyhelminthes. Strong magnification revealed actively moving flagella, scattered through the body, and similar to those which are found in the excretory system of various Vermes. Each flagellum is continued in a vesicular enlargement, and by its widened base completely closes the ciliated funnel, the free end of the flagellum being directed towards the efferent canal. No exact information can be given as to the branchings of the excretory system, or as to the character of its orifices. The absence of gills, buccal mass, and radula, as well as of a vascular system, proclaims Rhodope to be the very lowest of all known Nudibranchs; at the same time it is distinguished from the allied Turbellaria by its anus, by the structure of its generative organs, its central ganglia, and its sensory apparatus. Rhodope must not, however, be supposed to have been derived from the present specialized Dendreceela, but from a group of Rhabdoccelida, to which, in his forthcoming Monograph of the Turbellaria, the author intends to apply the term Alloioccla; this group will contain Vorticeros and others, and will be distinguished from the Accela and the true Rhabdoccela by characters which will, we think, be better understood when that subject comes before us. Molluscoida. Test-Cells in Ascidian Ova.t—These cells, so characteristic of the ova of Tunicates, obtained their name from the belief that they * Morph. Jahrbuch, viii. (1882) pp. 73-83 (1 pl.). t Zool. Anzeig., y. (1882) pp. 356-7. 492 SUMMARY OF CURRENT RESEARCHES RELATING TO eventually formed the test enveloping the Ascidian. This view was shown to be erroneous, and Professor J. P. McMurrich now enunciates a new theory as to their function.* The latest theories on the subject of parthenogenesis and of the nature of polar-globules are based on the assumption of the bisexual nature of the ovum, on account of which it is possible, and there is even a tendency, for a yolk to divide spontaneously. In most cases this is disadvantageous, and the formation of “ test-cells” is a means of guarding against the misfortune. On the exposure of the ova to sea-water or other abnormal condition a contraction of the yolk is brought about, and thereby a tension upon the nucleus, which, under the strain to which it is subjected, would divide, and so start the pro- cess of segmentation, were that strain not removed from it by the extrusion of the test-cells, whereby it is preserved intact until the proper stimulus in the shape of a spermatozoon excites it to a healthy and normal division. This theory the author would also suggest as an explanation of the Excretkorper described by Hertwig and Oellacher as appearing in the ova of Amphibia and fish respectively, and also of the fatty globules described by the late Sir Wyville Thomson as occurring in the eggs of Comatula, to which structures test-cells bear no little resemblance. Embryology of the Bryozoa.t—J. Barrois finds that the larva of a Bryozoon consists essentially of five principal parts; an aboral surface, the peripheral pait of the oral surface with the corona which is only the edge of it, the incubating pouch with the central part of the oral surface which is destined to form the intra-tentacular space, the intestine, and lastly, the rudiment of the polypite which already exists in the larva, where it forms a special organ, and takes more or less a part in the formation of the polypite. In the Entoprocta these parts have most nearly the arrangement which is found in the adult; the aboral surface forms the integument of the larva, and the oral is retractile and can be withdrawn into the vestibule; the only change necessary to convert the larva into the adult is a rotation of the incubatory pouch and the intestine so as to bring them into relation with the rudiment of the polypite. In the Chilostomata there is developed, by the aboral growth of the corona, a pallial cavity ;—as the oral surface has here lost its retractile power, there must be a change in the position of the mantle before the larva can pass into the adult condition; here, therefore, there is a more marked metamorphosis. In the Ctenostomata the pallial cavity is enormous, and the cells of the corona are of very large size ; in the Cyclostomata there is no corona, but the oral surface continues to grow towards the aboral pole; and here, therefore, we have, in its most marked condition, the process which has become more and more * Tn a previous paper he showed that the test-cells were produced by a con- traction of the yolk of the ovum, consequent on the action of various stimuli being formed, more or less distinctly according as the stimulus was capable of causing a greater or less contraction of the egg-contents. + Journ. Anat. et Physiol. (Robin) xviii. (1882) pp. 124-61 (1 pl.). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 493 marked the further we are removed from the Entoprocta; in con- sequence of this the oral surface, which was at first entirely enclosed in the interior of a cavity (the vestibule) and covered over by the aboral surface, has gradually passed more and more to the exterior so as to form by itself the external integument and to drive the aboral surface into the interior of a cavity (the pallial cavity). In the most differentiated types of the Chilostomata and Ctenostomata we have seen that the aboral surface has been driven into the interior; not- withstanding this, the uppermost portion of this surface which forms the organ called the “ calotte” has always been seen to be projecting. In the Cyclostomata, however, the pallial cavity is always closed and covered over. Adding to these the Lophopoda, we may make the following table: eaniaee Predominance of the aboral surface. Vestibule “oh cle a oO lg ak cla at its maximum. Intestine well developed. Chilostomata and Gah erates of the corona. A pallial cavity. Ctenostomata (sac reduced) The intestine reduced to a mass of globules. Cyclostomata and { Predominance of the oral surface. Pallial cavity Lophopoda (no sac). at its maximum. Intestine disappeared. The author points out that from the point of view of larval forms only we seem to find an essential character in the antagonism of the two great cavities at the poles, and, when we carry this further, in the greater or less development of the mantle. It is according to the ex- tension of this last that we find one or other of the two surfaccs of the larva best developed; when there is a median extension of the mantle we find, moreover, that the intestine has partly disappeared ; while when it is at its maximum condition of extension there is no intestine at all. When we come to look at the matter in a more general way we see that this development of the mantle is not a matter of so great importance, inasmuch as every form of larva, no matter to what type it belongs, can always be referred to a common type, in which there is no mantle, in which the oral surface is always within the vestibule, and the aboral forms an integument. The history of the mantle is, then, only a history of a series of adaptive modifications. Dealing with the mechanism of the metamorphosis, M. Barrois finds that if we try to construct a general type of adult Bryozoon we have to recognize (1) a foot corresponding to the oral pole, (2) the frontal surface, corresponding to that which answers to the oral, and (8) a tergal or anal surface. In the Entoprocta these can be easily made out, but in the Ectoprocta it is not always so distinct; in the forms where the zocecium is elongated we seem to have the primitive dis- position, in the flattened ones the tergal surface is increased in extent ; palingenesis is to be seen in the Ectoprocta, coonogenesis in the Entoprocta. As the author regards the Bryozoa as belonging to the Vermes he notes that, with the exception of the Rotifera, the Bryozoa are the only Vermes in which a telostomiate condition is con- stantly manifested, either in the larval or in the adult condition; in other words, the division of the body is on the primitive or gastrula 494 SUMMARY OF CURRENT RESEARCHES RELATING TO type, in which we see an oral and an aboral pole. A free-swimming Entoproctous larva is then formed on the same type as a Rotifer. Granting this, we must suppose that the Bryozoon is the result of a simple change of life; we know that these larvee often creep about on their oral surface. If this habit were to become permanent we should have in the change of habits a sufficient cause for the meta- morphosis ; the ciliary current carrying food to the mouth would, on passing it, abut against the anal extremity of the vestibule, and would gradually drive this back towards the superior extremity of the larva ; there would thus be produced the rotation, in which the digestive tube would be implicated. We may assume the earlier existence of a group of Probryozoa, free-swimming creatures, of a general Rotifer- form, only represented to-day by the larvee of some of the Entoprocta ; these on taking to creeping would have their form altered by a current of water. Her , New Adriatic Bryozoa.*—Dr. Piesser discovered in some material sent him from Rovigno in the Adriatic a Bryozoon, which he found difficult to determine on account of its having some of the characters of Gemellaria and some of Notamia, but he calls it Gemellaria, and considers that the definition of the genus must be widened to receive it. It consists of rows of double cells back to back, and the aperture occupies most of the front. A zocecium does not spring immediately from the zoccium below as in Gemellaria loricata, but grows in the manner of Notamia bursaria; further, at the commencement of each branch instead of a pair of zocecia, there is only one, out of which a pair grow. There are radicle fibres which start from the back of a pair of cells and grow out independently, instead of uniting together and growing in a bundle down the dorsal surface of the colony. The most perplexing point to Dr. Piesser was the occurrence of avicularia at the top of the zocecia, sometimes sessile and very minute, at others they are much larger and pedunculate. He thinks that these characters show that it is a connecting link between Gemellaria and Notamia, and if his interpretation is correct, about which opinions may perhaps vary, we may look upon this as another instance showing that the presence or absence of avicularia cannot often be relied upon for generic division. It may interest Dr. Piesser to know that although this curious species has not previously been described, yet it lives in the Bay of Naples, and has also been found from a locality outside the Mediterranean. Arthropoda. a. Insecta. Sensations of Sight conveyed by the Facet-eye.j—The experi- ments of Grenacher, Dor, and Exner, as to where the rays received by the compound eye of Insects ought to be and are concentrated, led to the most contradictory results, until Grenacher finally established the true view. Several points, however, as to the quality of the * Neunter Jahresber. Westfalisch. Provinzial. Vereins fir Wiss. u. Kunst, 1881. + Abh. Senckenberg. Naturf. Ges. xii. (1880) pp. 35-123 (3 pls.). ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 495 function of vision still required investigation. The close parallel with the Vertebrate eye which was attempted to be drawn, is quite fallacious. -Clearness of sight was said by Joh. Miller to coincide with long sight, and to be best exhibited in those eyes which have the greatest circumference—the greatest number of very small facets, large crystalline cones and dark pigment-mass; the nearer the object to the eye, he said, the clearer the view obtained of it. Dr. J. Notthaft believes the size of the facets and the length of the radius of the curve of the eye to be the only factors in its structure which have an important bearing on this point. With regard to the effect produced by the presence of a number of receptive and refractive units—the units of the compound eye—he believes that the edges of the units and fields of sight are in contact ; when the curve of the eye is perfectly spherical the fields are approxi- mately polyhedric, like the facets, but when the curve is eccentric, distortion appears as magnification increases. The smallest angle of sight is constituted by the angular distances between the directions in which two neighbouring retinal elements look, or even between two such ocular elements regarded as wholes. A few examples may be given of the actual condition of things in some specific eyes :— Difference a of istance at direction | yo, of Smallest Breadth Heading which the between F ei ‘S Angle of of Cn Sight-field two aces: Vision. Facets. Eve of a unit terminal of Eye = ent elements. mm. mm. Apis mellifica .. | 1042 | 54 |1° 56’ (or 0° 51)*| . -024 10-78 ‘| 67 cm. Formica rufa 51° 35 |1° 97° (worker) Sphinx convolvuli | 67° 39 | 1° 43’ Acherontia atropos| 20° VS or Sai nor 0° 42) 5 e037 3:0 81 cm. * Determined by calculation from the radius of the eye-sphere as compared with the breadth of a facet, In spite of its large minimum angle of vision, the insect eye affords, under certain circumstances, as great an amount of distinct- ness of vision as the human eye, or even greater; for there is no minimum limit to the distance of vision, and objects near the eye are seen more clearly than anywhere else; the distinctness of vision diminishes as the square of the distance from the eye: these relations for the following insects are :— Distance in mm. at which Amount of Clearness with a the Clearness Distance of =I. =0'1, 0. | 60 cm. Apis mellifica .. .. 1°35 177 3°36 0-000024 Sphing nerti 4. os 0°81 8°51 1:67 0:000035 496 SUMMARY OF CURRENT RESEARCHES RELATING TO The indistinctness produced by distance has the effect of reducing the image of (e.g.) an Ailanthus leaf to an outline in which the different lobes are almost entirely merged together, and almost all the detail lost (cf. Figs. 88 and 89). Exner’s view of the impression produced on the insect eye of the degree of rapidity of movement in any objects, viz. that it is inti- Leaf of Ailanthus glandulosa, showing part taken by the different portions of the compound eye in viewing it. Fic. 89. Effect produced on the retina by the leaf thus viewed. mately connected with the movement of the insect itself, must lead to absurd conclusions. Joh. Miiller’s view, that insects see objects only by means of the accurate perception of their illumination, is the most important point in the theory of mosaic sight (that of ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 497 compound eyes), and contains the key to its principle. Only those rays of light can affect the eye which fall on it in the radial direc- tion, i.e. in the direction of the long axes of the crystalline cones. Each retinula (retina of a single unit) receives a cylindrical bundle of light-rays from every visible object; exactly the same amount of an object is taken in, at whatever distance it is viewed, so the effect of motion is not produced by an increase in or reduction of the amount which is seen of a moving body. The action of direct sunlight on insects is evidently, from their sensitiveness to it, of great importance to them. Seeing that the angle which the rays proceeding from the orb of the sun make on reaching the earth is on the average 32’, the smallest angle of vision for a unit of any insect’s eye being probably more than 10’ (39' is the lowest known to the author, viz. in an Aischna), the single image of the sun would be spread, at the most, over three unit-eyes, and, at the least, over one ; while the minute unit of the human eye, having an angular distance of 10" only, can take in ;1, of the sun’s disk, and thus the disk occupies in the retina a surface 192 units in diameter, and covering about 27,000 rods. The amount of light which can be received directly by the facetted eye from the sun is far less than that received by the human eye, in fact only from 5,1, to »7boo of the amount received in the latter case. The bearing of this * striking fact on the habits of the insect is difficult to see, but it may be asserted that the insect’s eye is thus well provided against the effects of a too intense light, while its sensibility to minute grades of illumination from terrestrial objects remains incontestably one of its most important properties. For by far the greater amount of the impinging light is absorbed by the epidermic structures, and owing to the spherical curvature of the eye, the rays which reach it coincide in direction with the optical axes of but a few of the units, and so but a small portion of the receptive nervous region is affected by them ; thus only the ;yy%so0 part of the sun’s disk is perceived by a single eye. This view is supported by Grenacher’s opinion that it is the median (i.e. direct and unrefracted) rays of the pencil which strike a facet, which are the most important. The perception of an object in all its dimensions and of its relation to surrounding bodies cannot be learned, as it is to some extent in our own case, during the short life of the insect. Some idea of the character of the insect’s vision may be gained from the observed fact that the natural impulse of the insect is to court the darkness (e.g. the lower sides of leaves, the shade of grass, &c.), in order to avoid observation; their well- known delight in brilliant illumination forming merely an episode in their life of caution. Probably they are to some extent subject to optical delusion; thus when the sun suddenly goes behind the clouds, the surrounding objects, before so brilliantly illuminated, would appear to be at a greater distance, owing to their loss of light. To ascertain the relations of objects with regard to the surrounding space is the most important function of this organ in these animals, and especially the relation of distance from the eye itself; these ends are attained by the comparatively large angular distance which Ser. 2.—Vo.. II. 245 498 SUMMARY OF CURRENT RESEARCHES RELATING TO the closely apposed elements present. The actual distinctness of the features of the object is less important here than with the human eye. The reason for the existence of two forms of eye, simple and com- pound, in perfect insects, is that of separating the impressions of space and distance from those of distinct sight of the object (the latter end being attained by the stemmata or simple eyes). Four, on the whole strongly distinct, kinds of vision are differentiated in the animal kingdom :— 1. General sensation of the amount of light evolved in the environ- ment and of the relative position of its source ; analogous to our sensa- tion of warmth, and exhibited only in small organisms with trans- parent outer coverings, and devoid of special portions of the body adapted for the function. 2. Sensitiveness to colour and shades of colour; general orientation as to environment, power of recognizing known objects—the “eye-spots” of Vermes, &c. 3. Information as to relative positions of surrounding objects affording guidance of movements, with slight amount of guidance as to characters of object—compound eye of Arthropoda. 4. The most clear and faith- ful perception of the objects, the images reversed by a lens which strongly refracts light. The contents of a plane are the subject of this kind of vision, which does not convey to the brain the distance or mutual relations of objects ; the plane may be either single, at a constant distance from the eye, or there may be several at distances which vary within certain limits, as when accommodation comes into play. In this case the third dimension, viz. depth or distance of objects, is obtained by movements made by the eye-bearing individual, relatively to the objects viewed, materially aided by the power of accommodation, when this is present; in its absence, as in the case of the stemmata of Arthropoda, this impression must be very feeble, since the moving animal obtains nothing but a disconnected series of images of the objects as they come one by one within the range of its organs, “The phylogeny of the compound eye is deducible from the fact of the acquired character of the movements of Arthropoda; as the faculty of motion became better developed, the organs of sight became modified, pari passu, into that form which successfully met the requirements of this mode of motion, in the manner above explained; the highest degree of development being naturally reached in the Insecta. All winged insects are thus provided, while but few of the wingless forms, such as larve, &c., have this form of eye. The explanation of the peculiar character of the vision enjoyed by the compound eye lies in the lenticular curvature of the corneal facets, which do not act as Joh. Miller supposes, by magnifying the entering rays, but by admitting only those which are not likely to prove injurious; this appears to be shown by a comparison of the Insect with the Crustacean eye. The latter is remarkable (judging by the results obtained by Grenacher from Mysis) for its large angle of vision—3° 16’ in the instance taken—and is probably fitted to convey impressions from a distance not exceeding a metre. Taking into ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 499 consideration the density and other light-absorbing properties of the medium in which the insects live, the amount of light received from an object must vary approximately as the cube of the distance of the source of light, hence the wide opening of the eye, admitting as much light as possible. The same effect as the perspective which is obtained in air is here produced by the indistinctness of objects, owing to the opacity of the medium, in proportion to their distance from the eye. The structural causes for these differences are :—(1) the flatness or slight curvature of the Crustacean cornea, which does not hinder the entrance of any light which falls radially upon it, and (2) the strong convexity of the facets in insects, which causes refraction of the rays to a focus in front of the retina, and consequently a dimi- nution of the light which meets them; thus most of the hurtful rays —those whose direction is not exactly at right angles to the surface of the cornea—having entered the eye at its side, are again thrown to the side and absorbed by the walls and the pigment of the narrow tube, whose diameter at the apex only allows of the entrance of a small central pencil. With regard to the fate of strongly divergent rays, the refractive properties of the cornea would appear calculated to increase their brightness ; but this is the case only with objects at short distances, and has the advantage of giving distinct and recog- nizable images of objects within this range. Nervous System of the Strepsiptera.*—The nervous system of the Strepsiptera has not been subject to any special researches. C. Th. von Siebold ¢ only states that these insects (Xenos vesparum) have one thoracic ganglion ; but he does not say anything about the number of cephalic and abdominal ganglia. HE. Brandt’s researches have been limited to four females and one male of Stylops melitite, and one female Xenos vesparum, preserved in spirit, the results of which are as follows :— 1. The cephalic division of the neryous system consists of the ganglion supra-cesophageum only, the ganglion infra esophageum being absent. 2. The thoracic division consists of a large ganglion containing five pairs of nuclei; it is divided into two parts, an anterior and smaller one, corresponding to the ganglion infra-esophageum and to the first thoracic ganglion of other insects, and a posterior and larger part, which corresponds to the other thoracic ganglia and to some abdominal ganglia. The interior division supplies nerves to the organs of the mouth (like the ganglion infra-cesophageum) and to the first pair of legs. The posterior and larger division of this ganglion supplies nerves to the second pair of wings, to the thorax, and to different segments of the abdomen. 3. The abdominal division of the nervous system consists of one abdominal ganglion, situated in the last third of the body. It is * Abstract by the author of a memoir in Russian, St. Petersburg, 1878. Ann. and Mag. Nat. Hist., ix. (1882) pp. 456-7. ¢ Lehrb. d. vergl. Anat., i. (1848) p. 582. 24 2 500 SUMMARY OF CURRENT RESEARCHES RELATING TO oval, and is connected with the thoracic ganglion by means of a long thin cord. From this ganglion spring three pairs of nerves, of which the first and second pairs branch out in the fifth and sixth segments of the abdomen, while the last pair branch out in the last segment of the abdomen and in the rectum. This nervous system is as curious as that of some Coleoptera (Rhizotrogus solstitialis, Serica brunnea) and some Hemiptera (Hydro- metra lacustris), as it has no ganglion infra-cesophagewm. Insects which injure Books.—Professor A. Liversidge, of Sydney, sends us some specimens of Lepisma saccharina, and points out that “in Blades’ ‘ Enemies of Books, 3rd ed. (1881) pp. 61-3, he refers to the description of a book-worm in Hooke’s ‘ Micrographia’ (1665), and rather makes fun of the figure and description there given— ‘certainly R. Hooke, Fellow of the Royal Society, drew somewhat upon his imagination here, having apparently evolved both engraving and description from his inner consciousness.’ - People living in New South Wales and other of the warmer parts of Australia can, however, bear testimony to the accuracy of Hooke’s statements and drawing. The insect figured in the ‘ Micro- graphia’ abounds here amongst books and papers, and is wonderfully destructive to them. It does not do so much harm to books as it does to loose papers, maps, labels, &c., as it cannot well get in between the closely pressed leaves of a book, and it is on this account that the loose edges of piles of MS., bundles of letters, &c., suffer so much more than the central portions; writing paper, too, probably contains much more attractive matter in the way of size, &c. With this I enclose some scraps of paper showing the ravages of the insect (Lepisma), and also some of the ‘silver fish’ themselves, by which name they are commonly known here and also in India, whence I understand the name ‘silver fish’ originated. The destruction of labels is a very serious one, as the identity of a specimen may very soon be lost. The labels enclosed have only been written about fifteen months, and some hundreds have thus been rendered totally useless. In future it will be necessary to saturate the labels with a poison, such as corrosive sublimate. At times I have thought that, perhaps, the ‘silver fish’ instead of doing harm may be doing good—for wherever they are found we are likely to find pseudo-scorpions (chelifer), and it may be that the former prey upon the latter; though I think not.” Formation of Galls.*—M. W. Beyerinck finds that “ galligenesis ” affects a portion of the vegetal tissue, which becomes altered in character, and may then be known as galliplastema ; the galligenetic influence is due to the larve and not to the hymenopterous parent. The phenomenon of formation of the galls is absolutely indepen- dent of the lesions which the deposition of the eggs causes in the living tissues of the plant. Direct contact between the animal and the plant is not necessary for the production of the galliplastema ; there may be a layer of dead cells, or even the covering of the egg * Rev. Internat. Sci. Biol., ix. (1882) pp. 373-4. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 501 between them, and this intermediate space may be greater than the diameter of the larva. In the cases in which the animal that produced the gall had originally only one point of contact with the galli- plastema, the further inclusion of the larva is due to an annular investment of the plastema, which increases in extent and becomes folded over it. A temporary contact on the part of the larva does not produce a gall. The larve are fed by the development in the gall of a tissue the cells of which have thin walls and contents rich in oil and albumen. In their anatomical structure many of the galls have characters which appear to be completely foreign to the organization of the plants that nourish them. y. Arachnida. Anatomy of Phalangida.*—Dr. R. Réssler finds that the digestive system consists of three portions, of which the spacious midgut is provided with a large number of ceca; the sucking action is pro- duced by a layer of strong transversely-striated circular muscles, which is only continued on to the more anterior portion of the succeeding oesophagus; the lumen of this latter region is almost completely filled up by six longitudinal folds, consisting of a trans- parent cuticle with a subjacent layer; the cells of the salivary glands may be seen, in section, to form one layer and two smaller complexes below the cesophagus; the secretion has an acid reaction. All the thirty ceca are without a muscular investment, and consist only of a thin fat-layer, a tunica propria, and an epithelium; the Malpighian vessels are represented by two tubes, forming a loop, which are placed near the median ventricle, and open not into the intestinal tract, but into two sacs on the ventral surface of the animal. The genital organs of the two sexes are referable to a common plan, consisting as they do of an unpaired germinal gland, semicircular in form, lying freely in the body-cavity, and only surrounded by a rich supply of trachez ; there is connected with this gland a paired efferent apparatus, which however becomes united into an unpaired piece, and finally opens to the exterior in the median ventral line, between the cephalothorax and the abdomen. Connected with the terminal portion is a copulatory organ, into the anterior portion of which there open a pair of accessory gland-organs ; the penis is rod-shaped, the ovipositor is cylindrical, and the vagina has a seminal pouch on either side. The testis is a simple tubular organ about 4 mm. long and 0:4 mm. wide; the spermatozoa are large, biconvex, rounded cells, with a lens-shaped nucleus ; the vasa efferentia commence as two fine canals, and soon form a close coil; the cells of the lumen become commingled with the products of the testis; the propulsion-organ has a thick muscular layer, the fibres of which are transversely striated, and there is a thick chitinous layer secreted by the epithelium; the lumen of the ductus ejaculatorius is narrow; chitin is also to be found in the penis. The ovary is horseshoe-shaped, invested by transverse and longitudinal muscular fibres, and when mature is beset with a * Zeitschr. f. wiss. Zool., xxxvi. (1882) pp. 671-702 (2 pls.). 502 SUMMARY OF CURRENT RESEARCHES RELATING TO large number of follicles of variousages. These, which may be looked upon as evaginations of the tunica propria, all contain an egg, more or less developed, but the ova are always of small size until they make their way into the uterus, which then attain their full size and development. In the immature female the uterus 1s only apparent as a slight outpushing of the oviduct, but at the period of maturity it becomes turgescent, swells out, and occupies a large portion of the body-cavity ; itis provided with a powerful layer of circular muscular fibres, and its inner surface is lined with cells, similar in character to those of the vas deferens. The terminal portion of the vagina is surrounded by a system of chitinous rings; the ovipositor, like the penis, is surrounded by two sheaths, which are essentially of the same structure in all the species. The two glands at the lateral margins of the cephalothorax have been regarded by Loman as stink-glands; the author finds that in Opilio albescens there is an aromatic odour, which he ascribes to these organs. Scent-glands of the Scorpion-spiders (Thelyphonus).*—The re- markable Arachnidan genus T’helyphonus is confined in its distribution to South America and Southern Asia and their islands. Of its internal anatomy nothing but the nervous system is known. The French zoologist Lucas states that the Thelyphom are called Vinai- griers by the inhabitants of Martinique, on account of the strong vinegary odour which they emit when touched or handled. Stoliczka, who examined living specimens of one of the Indian species, states that a peculiar but inodorous fluid issues from two internal pyloric (!) appendages. These Arachnids, according to Lucas, live in damp places under stones on the ground. Stoliezka and Mr. Peal found them beneath the bark of decayed trees in groups. Mr. J. Wood-Mason, who has undertaken an investigation of their anatomy, was only able to obtain specimens for dissection during the heaviest rain, when all vegetation and the ground is saturated with water, and the animals come forth from their holes in the rocks. He found that death quickly followed their removal from their humid haunts, air saturated with moisture being apparently necessary for the due performance of their respiratory functions. All the specimens he met with emitted, when touched, a most powerful and lasting odour, exactly like that of a highly concentrated essence of pears, which when deeply inspired had all the characteristic smell and pun- gency of strong acetic acid. This odour did not emanate from the general surface of the body, but proceeded from a pellucid fluid which exudes from the neighbourhood of the anus and is secreted by special glands. These are paired and tubular organs of huge size, extending from the nineteenth somite of the body (on which they open by two minute valvular apertures placed at the sides of the anus) to the front end of the thirteenth in the male, but to the middle of the eleventh in the female (whose glands are consequently the larger), and being, with the exception of the voluminous liver, the most conspicuous of the viscera. They are two subpellucid bags, shaped somewhat like * Proc, Asiatic Soc. Bengal, 1882, pp. 59-60. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 503 an Indian club, striped longitudinally with white, and filled to dis- tension with a thin clear fluid. They are not quite equal, nor are they placed symmetrically in the body-cavity, but the one or the other lies between the nervous chain and the ventral body-wall in the middle line between the two rows of vertical muscles, and the other between the row of muscles and the lateral wall of the side of the body to which it properly belongs. They apparently consist of a strong and structureless basement membrane, invested externally by a layer of delicate striped muscular fibres arranged circularly, and of an inner membrane; the walls of the short (1 mm. long) ducts are transversely thickened so as to resemble the trachew of insects; the granular tissue is arranged between the two membranes in longi- tudinal plated stripes, so as to permit of the expansion of the lumen of the tubular organ in a receptacle or bladder for the storing up for use of the secreted fluid, to which apparent arrangement of the granular substance the striped appearance of the organs is due. The secretion doubtless serves to protect the animal from attack, and it is interesting to find that the female in this, as in so many other animals which are similarly protected by their offensive odour, is (as being for obvious reasons the more important sex) more perfectly protected than the male by having, not indeed, so far as could be detected, a stronger and ranker, and therefore more disagree- able scent, as in many insects, but larger scent-secreting glands. Another point of interest brought out by this investigation is that the two glands exhibit a tendency to coalesce and form a single unpaired median organ, the two being always unequal and occasionally partially united and the one in the middle line invariably the larger. These structures seem to belong rather to the category of excre- tory organs than to be highly developed skin-glands; and they are probably homologous with the silk-glands of other Arachnida and of Insects, with the green-gland of the Crayfish, and with the segmental organs of Worms and Peripatus. 5, Crustacea. Classification of the Brain of Crustacea.*—Dr. A. S. Packard gives the following provisional grouping of the brain of Crustacea, which he considers to be justified by known facts, although excepting the brains of Decapoda and Limulus, no special histological work has been accomplished. The terms archi-cerebrum and syn-cerebrum have been proposed by Professor Lankester, the first to designate the simple worm-like brain of Apus, and the second the composite brain of the Decapoda, &e. Decapoda. Tetradecapoda. Syn-cerebrum ( Phyllocarida. Cladocera. Entomostraca. Phyllopoda. Archi-cerebrum {Metta (Limulus). Cirripedia ? * Amer. Natural., xvi. (1882) pp. 588-9. 504 SUMMARY OF CURRENT RESEARCHES RELATING TO The syn-cerebrum of the Tetradecapoda, Amphipoda, and Isopoda, judging by Leydig’s figures and his own observations on that of Idotea and Lerolis,is built on a different plan from that of the Deca- poda. The syn-cerebrum of the Phyllocarida is somewhat like that of the Cladocera and Copepoda (Calanidz) ; being essentially different from that of the majority of the Malacostracous Crustacea. ‘The Copepodous brain is an unstable, variable organ, but on the whole belongs to a different category from the syn-cerebrum of other Neocarida. We have then, probably two types of archi-cerebra, and three types of syn-cerebra among existing Crustacea. Unpaired Eye of Crustacea.*—In most Crustacea, besides the two compound eyes (fused together in the Cladocera), there exists an unpaired median eye. It exists alone in most of the Copepoda, and in all naupliiform larve. Wherever the two kinds coexist in the adult but not in the newly hatched larva, the unpaired eye is the first formed, and must therefore be regarded as the primitive eye of the Crustacea. By thin sections of Cyclops and Diaptomus, Mr. M. M. Hartog has ascertained that this organ is of a much more complicated composition than had been supposed. The pigmented mass is, so to speak, structureless; the colouring-granules in it are placed at the surface contiguous to the “crystalline spheres.” Hach sphere is com- posed of radiating elements, the inner ends of which are applied against the pigmented mass, while the peripheral segments contain a nucleus. The eye is situated upon the terminal process of the brain, from which the optic nerves originate, one for each sphere; the nerve, instead of penetrating into the pigmented mass, skirts the outer surface of the crystalline sphere, and penetrates it directly not far from its hinder margin. The author has also found in the Phyllopoda a perfect analogy of structure with that just described in the Copepoda, and therefore concludes that the unpaired eye in all the Crustacea that possess it, is composed of three simple eyes, placed anterior to the brain, with reversed optical bacilli, receiving conductive fibres of the optic nerve upon their outer margin, and brought so close together that their pigmented or choroid layers are combined in a single mass. A nearly identical structure may be detected in the Chetognatha, which have the triple eye of the Crustacea; but, instead of being median and unpaired, it is repeated on the two sides of the head ; certain Planarians, Dendrocelum lacteum for example, have two paired eyes, which, according to Carriére, have the structure adopted by the author for one of the simple eyes united in the median eye of the Crustacea. It is probable that the eye of the Chetognatha and Crustacea is to be referred back to the type of the Planarians, but that the two former groups have no direct relationship between them. Blood of the Crustacea.t—G. Pouchet is reported to find that the differences seen in the blood of these animals is not, as Wharton * Comptes Rendus, xciv. (1882) pp. 1430-2. + Journ. Anat. et Physiol. (Robin) xviii. (1882) pp. 202-4. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 505 Jones thought, due to differences in the time of year. Their blood is remarkable for the large quantity of sea-salt which it contains, a drop from a Maia laid on a glass slide and dried giving a large number of crystals. Coagulation takes place very rapidly. Notwithstanding the great variation in form of the leucocytes, it is possible to re- cognize a common type; a large number have the form of young blood-corpuscles of oviparous vertebrates; as they grow older they present a number of granulations, and, as their nucleus is then often small or altogether lost, the author is of opinion that the granular condition represents the last stage in the development of these bodies. The form and the size appear to differ considerably as we pass from one species to another; the form, which is always ovoid, appears to be permanent so long as the blood is retained within the circulatory cavities; as an example of this we may cite the case of Palemon, where the leucocytes found in the lateral lobes of the telson did not, during a long period of examination, exhibit any amceboid changes. Pyloric Ampulle of Podophthalmate Crustacea. *—F. Mocquard describes the ampulle as forming the floor of the median part of the pyloric duct; in most cases they may be compared to two demi- cylinders placed side by side, with the cavity upwards. The surfaces are not, however, regularly cylindrical, for they are rounded and truncated obliquely behind. Their inner edges unite to form a pro- jecting longitudinal—interampullar—fold; from their cavities and from the sides of the fold there arise a large number of parallel longitudinal crests, on the free edges of which there are rows of ex- tremely fine sete; from this arrangement there results a considerable number of small prismatic canaliculi, directed from before backwards ; the free edge of the posterior portion of each of these ampullar crests is continued into a large seta, which is directed backwards and carries extremely fine sete. A remarkable point in this arrangement is that very slight differences are found even when the Stomapoda are com- pared with the Decapoda. Similar ampulle are to be seen in the larvee (and doubtless also in other forms) even when there is no gastric armature; while further, though absent in the Mysis, they are to be found in the Mysis-stage. We never find any appreciable amount of food in the ampullar cavities, and their functions would appear to be this: while the nutritious matters which are difficult of digestion remain in the superior portion of the pyloric duct, the more finely divided par- ticles make their way between the interampullar fold and the side- wall of the pylorus along a line parallel to, but in a contrary direction to that of the sete; they are thus broken and brought into a sufficiently fine state to enable them to penetrate into the canaliculi, whence they pass backwards in a longitudinal direction. In support of this view, the author directs attention to the fact that the excretory ducts of the so-called liver empty their products not far from the posterior orifice of the canaliculi, where the alimentary matters and this secretion would therefore be brought into intimate contact. * Comptes Rendus, xciv, (1882) pp. 1208-11. 506 SUMMARY OF CURRENT RESEARCHES RELATING TO Heterogeny of Daphnia.*—C. L. Herrick, in the course of re- searches upon the development of Daphnia Schaefferi (= magna), observed several interesting facts. The embryo, before leaving the egg, in both summer and winter forms, is furnished with palpi on the base of the second antennz, and a long appendage from the dorsal region of the shell. The former, though quite large in the embryo, is later nearly atrophied, remaining during life, however, as a wart-like process with two rather small spines. The latter is curved beneath the body, lying between the valves of the shell. After the escape of the animal from the egg this organ becomes the dorsal spine, and seems to serve as an aid to the complete moulting of the walls of the brood-cavity, with the first development of which the spine seems also to stand in intimate relation. It is worthy of remark that not only the mature animal, after long confinement in aquaria, becomes smaller and stouter, and in other peculiarities resembles the smaller spined species of Daphnia, but that the young retain the dorsal spine and the shorter form till in a sexually mature condition, when in confinement. This fact, and the discovery of Dr. Birge, that the spine upon the head of another species of Daphnia is also an embryonic organ, serve to call attention to the systematic position of this genus. It would therefore appear that the species Schaefferi is the culmination of a cycle of forms, among which are to be counted more or fewer of the species described as distinct. Daphnia thus furnishes another example of so-called “ Heterogeny.” Notodelphyide.j—W. Giesbrecht describes the female repro- ductive organs of these parasitic Copepoda. ‘The ovarian tubes are completely differentiated before the last ecdysis, when they present the following features; there is a structureless tunica propria lined by a simple epithelium, the cells of which are as broad as high. As changes occur, this epithelium becomes separated off from the wall of the tube; the process commences at the anterior end, and gradually passes backwards, so that in a series of sections the anterior ones are filled with the separated cells, while the lumen of the hinder ones is still open and the wall invested by epithelium; the cells do not break off separately but in longitudinal rows. When this process has come to an end, the walls of the tube are formed by a distinct membrane, which is lined by a layer of protoplasm; at first the nuclei in this latter are at some distance from one another, but they soon come to form groups of two to six. The tube, therefore, first had the function of a germ-producer, and may be called the ovary, while, later, it serves as an oviduct, and affords nutriment to the growing ovarian cells. Owing to their coming off in longitudinal rows, the ova now lying in the tube are arranged in cords of a cylindrical form, each of which may have as many as one hundred eggs; there is no investing membrane to these ovarian cords. A little later the * Zool. Anzeig., v. (1882) pp. 234-5. + MT. Zool. Stat. Neapel, iii. (1882) pp. 293-372 (8 pls.). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 507 separate cells begin to be distinguished from their neighbours; many of them increase in size by the growth of their peripheral portion, and the internal contents of these do not therefore become altered in character. Others develope within themselves fatty bodies. Under the influence of the growing ova the paired portions of the ovarian tubes increase greatly in diameter, and soon after this the eggs make their way into the maternal cavity, where they pass through the stages of development prior to the Nauplius condition. The dorsal folds are chiefly formed of a connective tissue, which consists largely of membranous elements and partly of spindle-shaped fibres, which may be regarded as muscle-cells; in addition to these there are rounded fibres, which extend from one surface to the other. Rounded or ellipsoidal bodies are to be found lying in the meshes of the tissue, filled by a very regularly arranged polyhedral meshwork of very delicate membranes. A number of fatty cords traverse the appendage in a radial manner; these are processes of the fat-body which is so frequently found in parasitic Crustacea and are here particularly well developed. The investing membrane is a continua- tion of the general chitinous covering of the body, though it is here more delicate than in other regions. As there is in all essential points the very closest agreement between the structure of these folds and that of the other parts of the body, it would be better to speak of them as processes of the body-cavity, than as dermal folds. The specially modified portion which serves as a brood-pouch has its internal lamella formed by a specially thick chitinous membrane, and is at first so folded as to allow of the increase in size of the cavity which becomes necessary later on. Some of the habits of these forms are treated of in detail, and it is pointed out that the first copulation commences before the final ecdysis of the female, but the attachment of the spermatophores only becomes completed after the ecdysis; in this action of the male, the appendages, and specially the fourth or fifth pair of feet, take part. Various males may fertilize the same female who remains completely passive during the whole act. ‘The reason of this apparently prema- ture copulation is considered, and the suggestion is made that it is an arrangement derived from an earlier condition in which the female did not pass through the last ecdysis. The succeeding acts of oviposition and delivery are described ; they are repeated at regular and constant intervals, whereas the later acts of copulation are not so definitely arranged. A female who has just deposited her ova, has a thin, faintly-coloured, hardly detectable ovarian tube; five days afterwards this is again filled, and the red eye-spots of the embryos in the brood-cavity can be made out. After ten days from oviposition, the embryos are ready for extrusion, and again the ovarian tube will be found full; for about two and a half days the brood-pouch remains empty. The author does not look upon the development of the fat-body as an arrangement which owes its origin to the struggle for existence, but as a passive necessary result of the parasitic habits of these animals; the assimilated nutriment which the free-living forms use 508 SUMMARY OF CURRENT RESEARCHES RELATING TO up owing to their activity, has no use in an organism which lives a parasitic life; and the physiological process is therefore completely similar to that which obtains in fattened cattle. ' The earlier part of the paper is taken up by (1) an account of the presence of these forms in certain Ascidians, the author only finding them in Phallusia mentula, and P. mammillata, where they are far from being the only guests; (2) a description of their external form ; and (8) a systematic account of the species, which are arranged under the genus Doropygus, with as subgenera, Doropygus and Notopterophorus. Seven species appear to be known. Organization of Trilobites.*—The veteran H. Milne-Edwards, in discussing the results of the researches of Mr. Walcott,f concludes that the alliance, on which he long ago insisted, between the 'Trilo- bites, Isopoda, and Phyllopoda, is strengthened rather than weakened by these studies; he cannot believe that they were representatives of the Arachnidan type from which the Limuli appear to have been de- rived, and he thinks that a group composed of Trilobites, Limul, and Eurypterina would be altogether artificial and inadmissible into a natural zoological classification. It is pointed out that although there is, at first sight, a very con- siderable resemblance between young Limuli and young Trilobites, yet that the latter soon become provided with thoracic segments, and, to cite characters of less importance, they tend to become ornamented with those long spiniform prolongations, the presence of which is so characteristic not only of Zoex, but of many adult Macroura. If we examine the respiratory organs of the Trilobites, we find them to differ much more from the Limuli than they do from the Branchiopoda or the Hedriophthalmata. The principal differences between the external structure of a Limulus and of a Phyllopod or an Isopod are to be found in the relations of the mouth to the appendi- cular system, and the mode of division of labour between the different parts. In the Limuli we find two distinct groups: one forms a masticatory, prehensile, and ambulatory system, at the centre of which we find the mouth; the other, the respiratory apparatus, is situated more posteriorly, and presents none of the characteristic forms of any Arthropod walking limb; no known existing animal has a similar structure, and no one of the recently observed facts leads us to see any close resemblance to them in the Trilobites. Prof. Milne- Edwards has now no doubt as to the existence of a long series of post- cephalic limbs in the Trilobites, and the characters of these appear to him to present a certain resemblance to those of Apus ; it is possible that they were almost altogether homomorphous and natatory rather than ambulatory. It is pointed out that we have an erroneous idea of the essential characters of the appendicular apparatus of the Phyllo- poda, if we imagine that they are always entirely soft and membranous ; in Apus the coxopodite and some of the succeeding joints of the internal ramus are thick and firm, and we can imagine that under the * Ann. Sci. Nat. (Zool.) xii. (1881) Art. No. 3, 33 pp. (8 pls.). + See this Journal, i. (1881) p. 736 ZOOLOGY AND BOTANY, MIOROSCOPY, ETC. 509 effects of fossilization nothing but the parts of this internal ramus might be left to be preserved. Vermes. Chemical Composition of Tubes of Onuphis.* — Professor O. Schmiedeberg finds that the tubes of this Annelid consist not only of a mixture of albuminoid substance and of potassium and sodium, but of a special body (onuphin) made up of organic and inorganic bodies ; the presence of this body may be explained by the view of Ehlers that the tube is a secretion of the separate segments of the animal, a view which is based on the plentifulness of the secretion of certain glands. The question of the origin of the chemical com- ponents is considered by a reference to the quantitative analyses of various sea-waters, and it is pointed out that the striated structure of the tube is due to the different layers being separated by an albu- minoid substance. The question of their food is not yet satisfactorily settled, nor have we yet the necessary knowledge of the exact consti- tution of onuphin. Nematoid Hematozoon from a Camel.tj—Dr. T. R. Lewis, recalling the fact that the occasional presence of nematoid organisms in the blood of various animals has long been ascertained, and that ten years ago he had shown that in India a somewhat similar condition was observable in man (associated with certain forms of grave disease), points out that an important contribution to our knowledge of the hematozoa of the lower animals has been made by Dr. G. Evans, the head of the veterinary department of Madras, who, whilst making a post-mortem examination of a camel, found that the blood of the animal swarmed with the brood of a nematoid parasite resembling the hematozoon of man, Dr. Evans found, further, that the parental form existed in the lungs, the pulmonary arteries of which were plugged by tangled masses of the thread-like parasites. They were also found in the mesentery. A comparison of these hematozoa with those found in man shows that, whereas the embryonal forms of both kinds are indistinguish- able under the Microscope, nevertheless the mature form as met with in the camel differs, both as to size and structure, from the only male and female specimen of the mature form met with in man which has hitherto been obtained in India; and so far as Dr. Lewis is aware, this hematozoon of the camel differs from any hitherto described parasite. Should further inquiry confirm the supposition that the parasite is new to science, he proposed that it should be called Filaria Evansi. A preliminary description is given of both male and female forms. Development of Marine Planaria.{— Among other important points, Prof. E.Selenka here discusses the affinities of the Planaria to the Ctenophora and the Nemertinea. We find a considerable * MT. Zool. Stat. Neapel, iii. (1882) pp. 373-92. + Proc. Asiatic Soc. Bengal, 1882, pp. 63-4. + Zool. Studien, ii. (1881) 44 pp. (7 pls.). 510 SUMMARY OF CURRENT RESEARCHES RELATING TO though not complete similarity in developmental history between the Planaria and the Ctenophora. In both cases (1) the endoderm arises as four large pale cells, and this layer gives rise to a quadri-radiate enteron, which is permanent in the Ctenophora, but modified in the Planaria. (2) The gastrula arises by epiboly, and the blastopore and permanent mouth are coincident in position. (3) Stinging cells are to be observed in both. (4) The embryo has in both a predominantly radial (symmetrical) arrangement, but in both this is later on more or less completely modified into a bilateral sym- metry. On the other hand—(1) There does not seem to be in the Planaria more than a feeble indication of an aboral sensory capsule with otoliths, such as seen in the Ctenophora. (2) A complete in- vestment of cilia is but rarely found in the Ctenophora, e.g. embryo of Eucharis. (3) Nothing comparable to the eight ctenophoral plates of the Ctenophora can be detected in the Planaria. The relations of the Ctenophora and the Planaria are hardly to be doubted. Turning to the Nemertinea, we find that in these the quadri- radiate symmetrical cleavage is confined to the very earliest stages, the endodermal cells are small, and there is no kind of communi- cation between the enteron and the celom; on the other hand, stinging organs are to be found on the proboscis, the blastopore and permanent mouth are coincident, and, in fine, the Planaria in some cases present intermediate conditions between the Nemertinea and the Ctenophora. The chief objects of the author’s investigations have been Lepto- plana tremellaris, L. alcinoi, Eurylepta cristata, and Thysanozoon diesingi. Eyes of Planarians.*—Former investigations { having done little more than elucidate the ewternal characters of these organs, J. Carriére hag applied himself to determining their intimate structure, especially that of the nervous elements. The method employed was preserva- tion by Lang’s method, viz. a liquid composed of chloride of mercury 5 parts, glacial acetic acid 5 parts, water 100 parts; after twenty minutes or half an hour the specimen was transferred to alcohol of 70 per cent.; sectious were made and stained with picrocarmine. In Planaria polychroa there is an optic ganglion immediately in con- tact with each eye, on its outer side, and consisting of an external layer of nuclei resembling those of the cerebral ganglion, and about -008 mm. in length, enclosing a larger mass of fine fibres. Among these fibres are some which are strongly refractive, and pass in straight lines inwards, swelling ‘out, and ending in rather broad knobs within the pigmented hollow (“ pigment-cup’’), and which they probably fully occupy in life. The pigment mass consists of small globules, varying in size from +255 to e457 mm. in diameter. The eye of Dendrocelum lacteum is double; the pigment-cup is single, but has two posterior openings instead of one. The eye of Leptoplana tremellaris, described by Keferstein in very different terms, appears, however, to agree - * Arch. Mikr. Anat., xx. (1881) pp. 160-74 (1 pl.). + See this Journal, i. (1881) p. 605. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 511 essentially with those just described. Study of pathological and abnormal specimens appears to show that the large eyes of the two former Planarians have been developed from aggregations of small ones, each consisting of a nervous cell invested by pigment; such eyes, in fact, appear in some cases as accessory appendages to the main organs. Polycelis nigra has the margin of the anterior end of the body beset with pigmented ocular organs, which are often united together in twos or threes. Their structure differs, however, very widely from that of the eyes of Planaria polychroa. Each eye consists of a homogeneous sphere, invested on its posterior side with a pigment- cup of distinct granules, which is open in front; in contact with the back of the latter organ is a large trausparent hemispherical nucleated cell. The eye appears to be surrounded by ganglion-cells whose nuclei are distinct, but whose exact relations to the eye have not been made out. Development of the Orthonectida.*—C. Julin, although agreeing with Metschnikoff in regarding Rhopalura ophiocome and Intoshia gigas as the male and female forms of the same species, has never been able to detect them both in the same Ophiurid. When an Amphiura squamata infested with males is opened there escape hundreds of individuals in different stages of development. After the first cleavage one of the blastomeres is very much larger than the other, and is more opaque; this is the ectodermic while the other is the endodermic globule. The former gives rise to as many as fourteen cells before the latter divides at all; thus there arises a condition of epiboly, where the endodermic cell is ovoid in form and has its long axis parallel to that of the embryo; the enclosed cell now undergoes division, and gives rise to a small cell at either end; one of these occupies the orifice of the blastopore. These small cells now divide into six and four respectively, and the ectoderm becomes completely ciliated; as the embryo elongates the small cells increase in length, and becoming fusiform completely envelope the central endodermal mass; in the adult they form the longitudinally striated fibres. Meantime, the central endodermic cell has divided into a large number of smaller cells, each of which contains a fragment of the primitive endodermal nucleus; each of these gives rise to a sper- matozoon. Although the primordial muscular cells have been given off from it, the central cell still possesses a true membrane, which persists during the whole life of the animal and forms a pouch for the contained spermatozoa. While the males are free the embryonic females are connected together by a granular mass (the sporocysts of Giard, plasmodial tubes of Metschnikoff). There would appear to be very great difficulties in the study of their earlier stages owing to this mode of connection. But here also there is ectodermic epiboly, though the endodermic cell divides earlier to give rise to a mass of polyhedral cells, sur- rounded by a layer of cubical non-ciliated cells. Later on these peripheral cells become cylindrical, and still later they form a com- * Bull. Sci. Dép. Nord, iv. (1881) pp. 309-18. 51D SUMMARY OF CURRENT RESEARCHES RELATING TO plete but very delicate layer of fibrils, apparently comparable to the muscular layer found in the corresponding position in the male. The central polyhedral cells give rise to ova. There is, therefore, an essential agreement between the developmental processes of the male and female. The male products escape, by the rupturing of their investing wall, into the muscular layer, where a passage is found for them ; the ectoderm undergoes change and atrophy, and the spermatozoa make their way out. The ectoderm of the female breaks off at a non- ciliated region at the anterior end, and thus the ova escape. There is another female form which seems to divide into two or three pieces, and which is distinguished by being flattened, and not cylindrical. The females, when mature, appear to leave one host to swim in the water and to enter another, and there is some reason to believe that the cylindrical forms give rise to the males, while the flattened forms would seem to be the parents of the females. These latter possibly arise by parthenogenesis. The author promises a fuller paper, in which he will give more details and full reasons for his belief that the Orthonectida belong to Van Beneden’s group of the Mesozoa, and he concludes with an ob- jection to the application of the terms metamere or segment to these creatures, as the segmentation is superficial, affecting only the ecto- derm, and the number of segments does, it is allowed, vary. Eyes of Rotifers.—Referring to his note read at the June meeting of the Society,* Mr. Badcock writes (July 17) :—“ Yesterday for the first time I discovered eyes in a group of adult Floscularia cornuta, and saw them again very distinctly in Stephanoceros eichhornii. It seems to me desirable to put on record the fact that the eyes are found in the adult forms of Melicerta ringens, M. tyro or tubicularia, Floscularia cornuta, and Stephanoceros eichhornii, in all of which the eye is ignored in the usual descriptions and drawings. ‘The eyes are not readily seen, but I have had some very fine specimens, and may be able eventually to demonstrate their existence in all the forms in which they were supposed to have been lost.” Echinodermata. Anatomy of Holothurians.j—E. Jourdan finds in the connective tissue of the integument of these Echinodermata elements forming a plexus; they are coloured grey by osmic acid, are rarely isolated, and are very often united into bundles. They arise from nerves which penetrate into and extend through the skin. The fibres of this nervous plexus are accompanied by nuclei, which are chiefly found at the points of interlacement of the fibres. These fibres are very fine, slightly varicose, and accompanied by fatty granu- lations. ‘The nervous centres consist of fibres and cells. The latter are frequently, though not always, unipolar. The muscular elements of Holothurians are made up of fibres * See this Journal, post, Proceedings. + Comptes Rendus, xciv. (1882) pp. 1206-8. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 513 which are remarkable for the irregularity of their form and their length. They are always provided with one or more nuclei, which are always lateral in position, large in size, and attached to the fibre by a delicate sarcolemma. The walls of the Polian vesicles consist of an outer layer of flattened cells, which recall the endothelial lym- phatic cell; a layer of connective tissue in which the fibres are longi- tudinal ; a layer of circular muscular fibres, which are very long, and have the appearance, when extended, of elastic fibres, in a state of contraction. They present a number of swellings. Within this there is a layer of epithelial cells. Hybridization of Echinoidea.*—R. Koehler finds that, at Mar- seilles, the genital glands of most species are mature in March or April. In making experiments, however, it is necessary to assure oneself by microscopical examination that the elements are ripe, and with the crossing experiments it is right to fecundate by their own spermatozoa the ova of the species treated. When the ova of Strongylocentrotus lividus were fecundated by Spherechinus granu- laris, the Pluteus was regularly and perfectly developed. The same happened when the male was Psammechinus pulchellus. When the male was Dorocidaris papillata, the eggs did not pass beyond the blastula-stage, but the spermatozoa used were here somewhat inactive. A female Strongylocentrotus is not always fecundated by a male Spatangus purpureus. Sometimes, however, even the gastrula-stage may be reached. Other examples are given, and the whole shows that cross fecundation is possible, within very wide limits, among the species of the Echinoidea; while the Pluteus derived from the crossing of two regular Echinoids may not differ much from the normal Pluteus of the female in the experiment, there are certainly well-marked differences between the legitimate Pluteus of a Spatangus and the hybrid Pluteus of that and Psammechinus. While the ova of one species may be fertilized by another, the reverse may not hold true. Variation in Asterias glacialis.|—Professor Jeffrey Bell describes “ six sets at least” of forms of this species. In the simplest there is never, in addition to the median row of spines along the back of each ray, anything more than a single isolated rather small spine on either side. Passing through forms in which there may be a few of these intermediate spines, or a larger number, we get to those in which there is a distinct row on either side of the now less conspicuous median one: two rows may be indicated on either side, or may be conspicuously developed. AIl the forms selected came from the coasts of Portugal, the Azores, or Madeira. It is pointed out that the character and arrangement of the pedicellarie depends on the distri- bution of the spines, and it is, in conclusion, suggested that in the history of the Asteroidea the next point to work out “is the nature * Comptes Rendus, xciv. (1882) pp. 1203-5. t Zool, Anzeig., v. (1882) pp. 282-4. Ser. 2.—Vot. II. 2M 514 SUMMARY OF CURRENT RESEARCHES RELATING TO of the sea bottom, of the surroundings, of the food, and of their enemies, as determining the strength, size, and disposition of the abactinal spines.” Ccelenterata. Development of Calcareous Skeleton of Asteroides.*—G. v. Koch having observed that between the crystalline calcareous substance which forms the septa of Mussa and the hyaline connective substance that surrounds it, there are cells which form a continuous layer, asked himself whether these cells secrete the calcareous skeleton, and do they belong to the connective substance (mesoderm), or are they ectodermal in origin, and, therefore, a secretion from the primitively external surface, which is only apparently internal ? To resolve these questions he has studied the development of the skeleton in Asteroides, where he finds that the first indications are only to be observed some time after the larva has become fixed. These appear as a circular disk with a cavity in the centre, consist chiefly of carbonate of lime, and are composed of spheroidal pieces, made up of concentrically arranged layers. The spheroids are larger in the centre, and decrease in size as they approach the margin of the disk. This earliest skeletal rudiment lies between the lower layer and the ectoderm of its aboral surface. The cells of the latter, like those of all other parts of the surface of the body, are cylindrical, and no calcareous concretions are to be observed within them. From these facts the author concludes that the first rudiment of the skeleton is neither a product of the endo- derm nor of the connective substance (mesoderm), but that it is a secreted product of the ectoderm. The further development of the skeleton is brought about by the completion and enlargement of this basal disk, and by the formation of septa. The former is effected by the formation of new spheroids, by growth, and by subsequent fusion ; the septa arise from radial endodermal ridges which attain a consider- able size. Later on, the ectoderm enlarges, and there appear cal- careous secretions, formed of small crystals, which fuse with the disk, and form the first rudiments of the septa. In the next stage the septa are higher and begin to branch at their peripheral ends. Growing still more, they broaden out, partly into the form of thin lamelle, get small spinous processes, and fusing at their peripheral ends with one another form the theca. The columella is similarly formed by a fusion of the central ends. While these changes have been going on there is a further secretion of carbonate of lime at the free edge of the young Asteroides. This unites with the aboral disk, and gives rise to a thin lamella. This is the epitheca of authors, and it is important to note that at first it is completely separate from the theca, and that it only secondarily becomes connected with it. Very little now remains to be observed, except the growth of the septa, theca, columella, and epitheca. We may remark, however, that from the primitively twelve septa there soon arise six which are stronger than the rest, and, alter- nating with them, appear to give rise to two cycles; twelve new septa * MT, Zool. Stat. Neapel, iii. (1882) pp. 284-92 (2 pls.). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 515 also begin to appear. Still later on, it may be seen that the septa form three or four cycles, which consist respectively of 12, 12, 24, and 48 pieces; the younger always appear between two older ones. Development of Aquorea.*—Prof. C. Claus states that Aquorea forskalea deposits its ova in March. They are without an investing membrane, and are deposited in great quantities. The directive cor- puscle is soon expelled, and just below the point at which it escaped a clear vesicle may be seen in the yolk for a few hours afterwards. The central cleavage-cavity is open at both ends until the 16-sphere stage. Later on, when these become closed, the region of the upper pole may be still distinguished by the greater thinuess of the walls of the hollow sphere at that point. As the cells become smaller, cilia appear on the surface, and the mass begins to rotate. It soon, how- ever, elongates, and becomes narrower near the lower pole, which is now posterior. The cells of this region become much higher, and gradually form a projecting process into the cleavage-cavity. Some of the more internal cells break away, and form isolated spheres within that space. This process goes on until the whole becomes filled with small cells, which represent the endoderm. At first there is distinct continuity between the endodermal cells, and the ectodermal from which they have arisen. On the third day the embryo presents all the characters of a Planula, and swims freely about. Stinging cells appear, and the long axis of the body is marked by a somewhat irre- gular line, which is the optical expression of a cleft in the endoderm, On the fourth and fifth days this cleft becomes wider and filled with dark granules. In this condition the larva swims about freely for some time. Fixation has not been directly observed. This polar ingrowth of the endodermal cells is not any kind of delamination, but has, as the author hopes to show in a further communication, a not distant connection with the other mode of development, which is known as that of invagination. Porifera. Hybridization in Fresh-water Sponges.j—Mr. E. Potts, in ex- hibiting some fragments of fresh-water sponges collected in the Boston Aqueduct, consisting of, it is believed, Spongilla paupercula and a new species, Meyenia acuminata (with others), points out the following exceptional features as marking the collection: (1) that all the statospheres, whether belonging to Spongilla or Meyenia, were smooth, that is, without a granular or cellular “crust”; (2) the apparent absence of dermal spicules in both, and the abnormal character of these belonging to the statospheres. The appearance is not infrequent, but has, so far as known, heretofore been limited to the genus Spongilla. The recurrence of the same feature in the associated genus Meyenia, coupled with the fact that many of the birotulates upon its statospheres were imperfect, the rays being more * Zool. Anzeig., v. (1882) pp. 284-7. t Proc. Acad, Nat. Sci. Philad., 1882, pp. 69-70. 2m 2 516 SUMMARY OF CURRENT RESEARCHES RELATING TO or less aborted approximating their shape to that of the spined fusiform acerates of Spongilla, gave rise to the suggestion that here, possibly, had been, not merely a mechanical mixture by inter- or super-position of species, but an organic hybridization produced by the flowing together of the amceboid particles of which the sponges are composed, or even by a fertilization of the ova of one by the spermatozoids of the other. ; It is important to note that the specimens were collected in February, when the sarcode matter had nearly all been washed away with, probably, accompanying changes in the presence or numbers of the smaller spiculz. Boring Sponges.*—Mr. J. D. Hyatt, referring to papers in the Journal of the Quekett Microscopical Club (in which the question is discussed whether Cliona forms the burrows in which it is found or whether they are excavated by annelids or other animals), is convinced that there is one weak point characterizing all the ob- servations, which invalidated to a great extent the conclusions on both sides. This was, that dried specimens had been used, or, as one author mentions, the live sponge occupying old shells and rocks. It occurred to him that a study of the live sponge occupying the shells ~ of healthy, living molluscs, might present evidence for one side or the other that had hitherto been overlooked, and he therefore procured some oysters, a considerable number of which had shells tenanted by Cliona. An exhaustive microscopical examination of these and similar specimens, seems to him to establish, beyond a possibility of doubt, that the sponge is, in this case at least, the only factor to be held accountable for the burrows. The outer layer of the shells was punctured with numerous holes, often many hundred, varying from the <5 to the z35 of an inch in diameter, generally occupied by the oscule of the sponge. Between the outer and inner layers, and extending laterally, the shell was almost entirely excavated, and the space occupied by the sponge and its numerous spicules; while extending inward from this sponge-mass were innumerable minute, branching and ramifying burrows, uniformly and completely filled with corresponding arms of sponge, many of which extend quite through the interior layer of shell. The contact of these arms with the external membrane of the oyster causes the latter to deposit at such points an additional amount of lime carbonate, and the interior surface of such shells presents the appearance of numerous little prominences caused thereby. The only possible theory that will account for these burrows, if they are not made by the sponge, is that they are the deserted ex- cavations of worms; but this theory is untenable, as it would be necessary to suppose that the shell was once inhabited by an innumer- able multitude of such worms; otherwise the perforations through the inner cell would have been closed, and all of these must have retreated at the same time, so completely that no trace of them could * Amer, Mon. Mier. Journ., iii. (1882) pp. 81-4 (8 figs.). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 517 be found, and the sponge must then have extended its growth into the deserted channels with such rapidity as to fill every minute branch before the oyster could bar it out by the secretion of enough new shell to stop apertures z0'55 inch diameter. But this is not all. The burrows occupied by Cliona branch in all directions and diminish in diameter as they extend inward, which would represent a method of boring quite inconsistent with the habits of any known borer. Again, in these specimens, the sponge was found in small spots on the thin lamine, around the sides and anterior edges of the shell which represent its most recent external growth, and in such cases the lamine were perforated from side to side. Protozoa. De Lanessan’s Protozoa.*—This will be found a welcome book by microscopists, as it is copiously illustrated with woodcuts and deals with the subject in a very readable form, while yet being far beyond a merely popular handbook. The author’s leading divisions are Monerans, Ameebans, Forami- nifera, Radiolaria, Infusoria (flagellate, ciliate, and tentaculate), and he claims to have originated a new plan for such a book differing from that of ordinary treatises. He commences in each case with con- sidering in its adult state an individual species chosen as the best type of the group (by its being readily procured, best known, &c.), dealing with all the details of its organization, with its physiological functions, its habits, and the development of its organs, considerable importance being given to embryology. He then describes the other leading forms of the group, and when all these have been disposed of a separate chapter sums up the common characters of the group, its relations with neighbouring groups, and its classificatory divisions. The author considers that a great mistake is made when the converse course is adopted and the characters of the group are dealt with, noticing the peculiarities of the organization of the different types of the group in the course of the general description. By this method, he says, “a Mollusc becomes a kind of abstract entity clothed with characters rendered so vague by the generalization that the student has the greatest difficulty in discovering them in. the specimen given him to dissect.” Taking the Amcebans for an example the following is the author’s arrangement :— 1. The principal forms. (a) Gymno-Ameebans. Under this head are described A. princeps, A. coli, Podophrys elegans, Pelomyxa palustris, Dactylospherium radio- sum, D. polypodium, D. vitreum, Hyalodiscus rubicundus, Petalopus diffluens, Plakopus ruber, Podostoma filigerum, and Mastigameba aspera 9 figs.). (b) DU eee sait “Pactedoabinigs patella, Cochliopodium pel- lucidum, Difflugia oblonga, Quadrula symmetrica, Arcella vulgaris, and Amphizonella violacea (6 figs.). * J. L. De Lanessan, ‘Traité de Zoologie. Protozoaires,’ vii. and 336 pp. (281 figs.) 8vo, Paris, 1882. 518 SUMMARY OF CURRENT RESEARCHES RELATING TO 2. Common characters, classification, and affinity. The author defines Amcebans as Monerans which have acquired a nucleus and contractile vacuoles, and distinguishes 17 genera, a third group of flagellate Amcebans being here formed of the gencra Mastigameba, Reptomonas, and Rhizomonas. Kent’s Manual of the Infusoria—This is now completed by the issue of the 6th part and forms a magnificent monograph of the Infusoria which cannot fail to be of the greatest value and assistance to the microscopist. The concluding part has an appendix containing a notice of species recorded during the publication of the work, a glossary of technical terms, an extensive bibliography of the Infusoria, and a plate illustrating the apparatus employed by Messrs. Dallinger and Drysdale and by Professor Tyndall in their investigations on Monads, &e. The plate also contains a figure of a Microscope and lamp arranged for working with high powers, the Microscope being horizontal and the lamp turned with the narrow edge of the flame towards the condenser. The plan described is by no means the novelty which it is suggested to be; it is, in fact, the one adopted - since the days of Quekett for all delicate high-power work. Flagellata.*—In a previous communication J. Kunstler} recorded the results of researches undertaken on the Flagellata, to which more recent observations enable him to add some new facts. Cryptomonas ovata Ehrbg., after being submitted to the action of acetic acid, appears to be covered with filaments; Biitschli, who has described analogous productions in Chilomonas paramecium Ehrbg., considers that they are trichocysts, that is, organs of defence com- parable to the nematocysts of Coelenterata; the author, however, has never been able to see in this organism the small rods which are so abundant in the integuments of certain ciliated Infusoria, and within which, if the comparison with urticating organs is correct, the attenuated prolongations should at first be enclosed. The filaments, incomparably more numerous than those which have been figured by Biitschli, form a thick peripheral layer, and their length is often enormous, thus there are some ten times the length of the body; generally they take an upward inclination. At the upper part of the body, on the prolongation of the posterior margin of the hollow in the digestive chamber, two or sometimes three of these prolongations may be observed which are thicker, longer, and more rigid, whilst the others are often slightly flexible. Cryptomonas erosa also has these filaments. In the cold season, Cryptomonas ovata acquires special characters. The nucleus only contains the large nucleolus. The cuticle is generally very thick over the whole surface of the body, and the vacuoles in it are very easily visible without the intervention of any reagent ; in certain points this cuticle presents a very considerable development, for example at the lower extremity where it forms a * Comptes Rendus, xciv. (1882) pp. 1432-3. + Ibid., xciii. (1881) pp. 746-8. See this Journal, ante, pp. 62-3, ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 519 prolongation directed backwards, or better at the dorsal rostrum (which is itself prolonged) where it often forms a long point. It also presents, besides the line devoid of green colouring matter, the existence of which on the left face the author has already recorded, another, colourless, tolerably broad, longitudinal line through the whole length of the right face. Finally the starch-grains of the deep mamillated layer are rarer and very thin; but extending over almost every part of their body are seen some irregular more refringent corpuscles resembling concretions, which are perhaps also formed of starch, although they do not turn blue under the influence of iodine. In an infusion that was in an advanced state of decomposition the author has met with Chilomonas paramecium Ehrb. in a sort of palmelloid state; a number of individuals of this species being united in a common transparent gelatinous mass, having a great resemblance to a Zooglea. Cienkowski has observed an analogous phenomenon in Cryptomonas polymorpha, and was confident that it was a mode of reproduction. The author has never observed this phenomenon except in cultures which were more or less putrefied and placed in unfavourable conditions with regard to light; these organisms are always isolated and very active in clear water well exposed to the light. Astasia costata has a muscular, subcuticular layer with spiral fibrille analogous to those in the Euglene. The contractile vesicle of Phacus pleuronectes Duj. has distinctive vacuolar walls resembling those of the analogous organ in Cryptomonas. The terminal flagellum of Monas vinosa Ehrbg. that Cohn considers to be merely the mobile spore of Clathrocystis roseopersicina (a chromogenous bacterium), displays a transverse striation when it has been submitted to the action of reagents that colour strongly. Cell-parasite of Frog’s Blood and Spleen (Drepanidium ranarum),*—-In 1880 we referred f to a discovery made by Dr. J. Gaule of certain Wiirmchen or “vermicles” in frog’s blood, which he considered to be simply protoplasmic portions of the corpuscles separated for a short independent life, and not parasitic organisms. Prof. Ray Lankester now points out that these are, in fact, the minute, sausage-like parasites, discovered by him in 1871 (for which he proposes the name of Drepanidium ranarum), and that they are clearly parasitic organisms, probably the young stage of a sporozoon allied to Sarcocystis or to Coccidium. Some of the chief observations of Dr. Gaule are, in fact, directly favourable to the view that the Wiirmchen are independent parasitic organisms, for (1) they exhibit active movements under circumstances usually favourable to the movements of the Protozoa and Protophyta ; (2) they occur within the cells of the organism in which they are found as well as in its fluids; (3) they are present in some frogs and not in others living under approximately the same conditions ; (4) they vary in abundance in the same frog, examined at different times ; * Quart. Journ. Micr. Sci., xxii. (1882) pp. 53-65 (5 figs.). ¢ This Journal, iii. (1880) p. 232. 520 SUMMARY OF CURRENT RESEARCHES RELATING TO (5) they are abundant in one time of the year and not at another; (6) they are seen on the stage of the Microscope to penetrate and enter cells by means of their active movement ; (7) they are also seen to escape from cells by the same activity; (8) they are localized chiefly in the spleen though not confined to that organ ; and (9) though most abundantly observed in certain specimens of Rana esculenta at Leipzig, yet they have also been observed in Rana temporaria and in Triton sp. : These observations are not merely consistent with the view that Drepanidium is an independent parasitic organism, but are directly in favour of that view, since they are readily explained if that view be admitted, whilst they remain as isolated and unconnected facts, each requiring a special assumption for its connection with any other theory which may be advanced as to their nature, when the obvious one that they are parasitic organisms is rejected. The only fact which Dr. Gaule adduces which is inconsistent with the parasitic nature of Drepanidium is that in some cells, especially blood-corpuscles, these bodies are not present when an examination of them is first made on the field of the Microscope, and that on the addition to the preparation of 0:3 per cent. solution of sodium chloride the Wiirmchen are formed there and then in the cells. Prof. Lankester, however, doubts altogether the accuracy of Dr. Gaule’s statements on this point, the supposed fact being really an erroneous interpretation of an observation. Just as the nucleus in the frog’s red corpuscle is frequently not visible during life and only becomes visible as the result of the first change in blood removed from the blood-vessels, so Drepanidium is invisible in the normal condition of the red blood-corpuscle owing to the identity of the refractive index of its delicate substance and that of the body of the corpuscle. It only becomes visible when a change in the refractive indices takes place. Prof. Lankester suggests that researches should be directed to the discovery of a Gregariniform stage, and of cysts containing spores, or of isolated spores in which several Drepanidia may be enclosed. These phases in its life-history are very possibly to be met with in other regions of the frog’s body than the blood-vessels or the spleen. Development of Trypanosoma.*—Dr. J. Gaule has also re- investigated the remarkable organism of Flagellate character found in frogs’ blood, the so-called Trypanosoma sanguinis Gruby, and puts forward a decidedly new and original interpretation of it, arriving at the conclusion that it is not an independent organism, but is produced by spontaneous modification of the white blood-corpuscles. Its pro- duction is favoured in general by warmth, hence it is found in frogs more particularly at the commencement of the warm period of the year, and it may also be seen to occur during the winter in frogs which have been kept in a warm room. These conclusions are attempted to be supported by the fact that the direct and frequent * Arch. Anat. u. Physiol., 1880 (Physiol. Abth.) pp. 375-92 (1 pl.). ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 521 conversion of white blood-corpuscles into Trypanosoma (or Kymato- cytes as Gaule proposes to call them) may be observed on the warm stage. The transmutation of the white corpuscles is said to take place as follows :— At one point in the periphery of the corpuscle is developed a vibrating flagellum from which is subsequently but gradually pro- duced a hyaline undulating ribbon; ultimately the whole body becomes flattened out and the flagellum degenerates into a pointed process of the lobate mass thus formed. The fully developed kymatocytes show such exuberant multiplicity of forms that the writer is able to distinguish no fewer than five types among them. Conversely, however, the Trypanosoma have the power of being re-converted into leucocytes with amceboid movements. Gaule, according to his showing, has directly observed the process of re- conversion, which he describes, many times, and he elucidates it by pictorial representations of the successive stages. One circumstance which appears to be of special importance in the matter is not made clear in the memoir, namely that as the white blood-corpuscles of the frog are known to be provided with a number of small nuclei, the Trypanosoma ought also to exhibit them, but neither are they described or do any cell-nuclei appear in the figures. This point seems to Prof. O. Biitschli* the more important, because in the life-history of certain Protozoa (cf. especially Ciliophrys Cienk.), amceboid and flagellate stages succeed one another, so that a similar alternation in the life-history of Trypanosoma proves nothing of itself as against their Protozoan nature. Indeed, the very point whether these amceboid bodies whose transmutation gives rise to the Trypa- nosoma, really are white blood-corpuscles, appears to Prof. Biitschli to be by no means free from uncertainty notwithstanding the present investigations. Prof. Lankester also considers + Dr. Gaule’s views to be “ devoid of justification.” New Gregarines.{—Dr. R. Réssler found in the enteric canal (chiefly the ceca) of the Phalangida, among other parasites, two Gregarines which appeared to be new. Actinocephalus fissidens n. sp. has twelve pairs of cleft hooks on its head, and between each pair there is a simple spiniform process. Stylorhynchus caudatus has the “head” placed on a stalk, and provided with twelve ridges or projections, which extend beyond the margin of the head and then divide. This form is also provided with a delicate caudiform ap- pendage, which is not separated from the body proper by any septum. In some cases these parasites were so numerous that the death of the host may be ascribed to their presence. * Zool. Jahresber. Neapel, i. (1880) p. 165-6. t+ Quart. Journ. Micr. Sci., xxii. (1882) p. 65. } Zeitschr. f. wiss. Zool., xxxvi. (1882) p. 700 (2 figs.). 522 SUMMARY OF CURRENT RESEARCHES RELATING TO BOTANY. A. GENERAL, including Embryology and Histology of the Phanerogamia. Chemical Difference between Dead and Living Protoplasm.—Dr. O. Loew sends us a photograph illustrating his researches on this subject,* from which Fig. 90 is copied. The upper part of the woodcut shows a filament of Spirogyra nitida Ktz., killed by a 0°1 per cent. solution of citrie acid before Fig. 90. treatment with the silver reagent, no blackening being produced, and the spiral arrangement of the chlorophyll-bands being distinct. The lower part shows a filament when placed in the living condition into the silver reagent, the reducing effect of the living protoplasm on the silver-salt having converted the cell-contents into a black opaque mass. Killing of Protoplasm by Various Reagents.t—Loew and Bokorny have applied their test for distinguishing between dead and living protoplasm, viz. its power of reducing dilute alkaline silver solutions, to determine the degree of resistance offered by protoplasm to various destructive agents. After complete withdrawal of light for five days, about 50 per cent. of the filaments of several species of Spirogyra still showed signs of life ; it was not till the sixteenth day that all were completely killed. ‘Twelve hours’ desiccation over con- centrated sulphuric acid destroyed the appearance of life in almost every cell. Triturating in a mortar destroyed life, even where there was no apparent injury. After warming in water of 46° C. for a short time, about 10 per cent. of the cells still showed signs of life, at 55° about 2 per cent.; and a temperature of 60° altogether destroyed life. Exposure of one hour to vapour of ether destroyed life except in some cells containing a large amount of oil and in spores, sugar being formed during the process. After twelve hours in chloroform- water, 5 per cent. of the cells were alive; two days in petroleum * See this Journal, i. (1881) p. 906; ante, p. 67, 361, and 440. } Pfliiger’s Arch. f. d. gesammt. Physiol., xxvi. (1881) pp. 50-9. See Bot. Centralbl., ix. (1882) p. 392. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 523 destroyed all power of reaction, causing copious formation of sugar ; absolute alcohol destroys life in an extremely short time. Exposure for twenty-four hours to a stream of carbonic acid destroys the life of the cells. Hydrochloric acid and citric acid produce an injurious effect almost immediately. The power of resistance to alkalies is much greater. Immersion for one hour in a 10 per cent. solution of sodium chloride destroys most of the cells. Metallic poisons act more slowly ; some cells still show signs of life after immersion for two hours in 1 per cent. solution of sugar of lead, or for twelve hours in 0-1 per cent. of arsenic acid, or for twelve hours in 1 per cent. of zine vitriol. Of organic poisons, gallic acid, pyrogallol, resorcin, hydrochinon, in 1 per cent. solutions, act rapidly, destroying life in a few hours, as also 0°2 per cent. salicylic acid, and 1 per cent. carbolic acid in one hour. Alkaloids, acetate of strychnin, chinin, and very dilute veratrin do not prevent the reaction, although the structure of the protoplasm is destroyed; 1 per cent. sulphuric acid destroys the power of reaction. Apical Cell-growth in Phanerogams.*—In order to determine the much-disputed cause of the want of a special apical cell in flowering plants, G. Haberlandt has closely investigated the process of apical cell-growth in the following instances: the cell-divisions of the cortical parenchyma in the laburnum and in the trichomes of the leaf-stalk of Begonia Rew ; the formation of the stomatal apparatus and neighbouring cells in Mercurialis and in Crassulacee ; the cell- divisions in the formation of the hypodermal bast-cambium bundle in the leaves of Typha latifolia ; the formation of the midrib of the leaf of Elodea canadensis ; and the formation of the leaves and axillary shoots of Ceratophyllum demersum. The general conclusions arrived at are, that in Phanerogams there are tissues and masses of cells of very different extent and significa- tion, which have been formed by apical cell-growth. It may be either rows of cells only that increase by apical growth, as in the first and second of the above instances, or plates of cells, as in the third, or finally masses of cells may exhibit apical cell-growth, as in the two last. Each of the three tissue-systems of Hanstein, der- matogen, periblem, and plerome, grows at first by means of a single apical cell. Development of Bordered Pits.t—E. Russow has carefully in- vestigated the development of bordered pits, and of the membrane of wood-cells, more particularly in the Abietinew. The general con- clusions at which he has arrived are the same as those of Sanio. The growth of the wall of the border points to the interpretation of a kind of secondary division-wall, as if a free membrane were excreted on the upper side of the protoplasm. * Haberlandt, G., ‘Ueber Scheitelzellwachsthum bei den Phanerogamen,’ 29 pp. (2 pls.). Graz, 1881. + SB. Dorpater Naturforsch.-Ges. Sept. 24, 1881. See Bot. Ztg., xl. (1882) p. 182. 524 SUMMARY OF CURRENT RESEARCHES RELATING TO Development of Tissue as a Characteristic of Groups of Plants.*— M. Westermaier thus sums up his conclusions on this subject. The results of anatomical investigations in reference to affinity differ accord-: ing as the physiological idea of the subject is taken into account or not. In the latter case the result is either faise or uncertain, while the former leads to a comparison on a rational basis. This last method of inquiry results in the conclusion that in the Primulacez the presence of a ring of bast may be regarded as an anatomical family character. In Campanula, while one group has in the stem the ordinary ring of vascular bundles with the phloem on the outer, the xylem on the inner side, a second group of the genus has a phloem- bundle in the pith, with or without xylem, a difference connected with physiological functions. Stomata of Polycolymna Stuarti.,—The more or less complete fusion of two or even of three stomata into one, has frequently been noticed as an exceptional phenomenon. In Polycolymna Stuarti (Composite) F. Hildebrand states that it is so common, both on the stem and on the leaves, that it may be regarded as a normal occur- rence. The relative position of the two clefts in these double stomata varies greatly. In some cases they are parallel, in others at right angles to one another, while sometimes again one is behind the other, so that only one pore belongs to the two clefts. ‘The mode in which the guard-cells are formed out of the ordinary cells of the epidermis appears also to be subject to great variation. The author was un- able to determine whether the cells strongly charged with protoplasm divide directly into guard-cells, or whether this is only effected after repeated division ; both processes appeared to take place. The direction of the septum in consequence of which the guard-cells are formed, is also very various; it is sometimes vertical, sometimes parallel to the wall by which the mother-cell of an epidermal cell is cut off. The occurrence of double, and occasionally of treble stomata, may be attributed to these numerous variations in the mode of their formation. The stomata of Polycolymna Stuarti present also other peculiarities. The guard-cells are placed-in various positions as to height in relation to the surrounding epidermal cells. Usually the outer walls’ of the guard-cells are about at an equal height with those of the sur- rounding cells, and this is almost invariably the case with double and treble stomata. But among these are others, distributed irregularly, the guard-cells of which are more or less elevated above the sur- rounding epidermis, this variation being possibly connected with their special function. The number of stomata is about the same on the under and upper surfaces of the leaves; on the under surface they are protected by densely crowded glandular hairs, on the upper side by a dense felt of silky hairs. The stomata with most elevated guard-cells are found * MB. K. Akad. Wiss. Berlin, 1881, pp. 1050-70 (1 pl.). + Bot. Centralbl., ix. (1882) pp. 356-61 (1 pl.) ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 523 on the under surface. They are also very numerous on the upper part of the stem, where they are also protected by glandular hairs. Properties and Mode of Formation of Duramen.*—J. Gauners- dorfer gives an historical réswmé of what is known respecting the duramen, which is distinguished by frequently containing gummy and resinous substances in its vessels or cells, as well as large deposits of carbonate of lime. His own observations he sums up as follows :— The production of duramen takes place in consequence of the elements of the wood becoming filled by derivatives of the solid woody substance; these products being formed to some extent in the part which becomes indurated, and partly in neighbouring portions of the wood; by this means the extent of duramen is increased. These substances must originally be fluid and rich in tannin; but the cells contain also other substances which give to the duramen its great power of resistance. Nitric acid or ‘“ macerating fluid,” and then potash- or soda-ley, remove most of these substances, except in the case of Diospyros. If the induration is carried on suffi- ciently long, the cell-walls are also partially destroyed, and the pro- ducts of decomposition mingled with the contents. The composition of the substances contained in the duramen varies with the species; that of the Amygdalez, for example, contains gum (?), of the conifers resin, of Syringa resinous substances. The purpose of the duramen, at least in the lower parts of the branches, is to furnish a protection for the sound wood against the influence of atmospheric agents. History of Assimilation and of the Functions of Chlorophyll.t— A. Hansen gives a list of the researches and conclusions on this subject from the days of Ingenhousz, Senebier, and Hales. The first scientific explanation of the phenomena he considers to be that of Sachs, between the years 1862 and 1865, that the starch in the chlorophyll-grains is a product of the living chlorophyll, and is pro- duced in the chlorophyll by its power of assimilation. The author criticizes unfavourably the views of Pringsheim with regard to the nature, mode of formation, and functions of hypochlorin. Theoretical View of the Process of Assimilation. — In his investigations on the chemical constitution of protoplasm,§ J. Reinke was led to frame a hypothesis as to the immediate products of the reduction of carbonic acid. He points out that this gas, CO,H,, may be subjected to three degrees of deoxidation. By the removal of one combining proportion of oxygen it becomes formic acid, CO,H,, which he states is always formed in every vegetable cell. The second stage of deoxidation reduces it to formic aldehyde, COH,, a remarkably + Hansen, A., ‘Geschichte der Assimilation u. Chlorophyllfunction,’ 90 pp. Leipzig, 1882. Also Arbeit Bot. Inst. Wiirzburg, ii. (1882) pp. 537-626, { Bot. Ztg., xl. (1882) pp. 289-97, 305-14. § See this Journal, ante, pp. 361-2. 526 SUMMARY OF CURRENT RESEARCHES RELATING TO polymeric substance, two of its isomers being oxymethylen, C,H,O3, and glucose, C,H,,0,. The result of complete deoxidation is the production of methylene, CH,, a substance which cannot itself exist independently, but which again has a very large number of isomeric hydrocarbons, as diamylene, C,,H,), triamylene, C,;H.,, and tetra- mylene, C,,H,,; the highest members of this series being solid and crystallizable. With this process of reduction is associated a process of oxidation in the chlorophyll-grains, and the resulting products are derived from the balance of these two processes. The most common stage of reduction reached is that of formic aldehyde. Reinke believes that this hypothesis is in harmony with that of Pringsheim regarding the formation of hypochlorin. A portion of the formic aldehyde is reduced to the hydrocarbon condition; and the hypochlorin results from a condensation of such groups. Passing from the reducing region of the chlorophyll-grain to the respiring portion of the cell, it is there oxidized into the volatile fatty acids. Both formic aldehyde and hypochlorin are very readily oxidizable, and require the protection of the chlorophyll to prevent their oxidation. First Products of Assimilation.* — A. Mori has performed a fresh series of experiments, chiefly on Spirogyra, which confirm his previous conclusion that the first product of assimilation in chloro- phyllaceous plants is an aldehyde, probably formic aldehyde, formed according to the following equation out of the elements of carbonic anhydride and water :—CH,O, = CH,O + O.,. Absorption of Metallic Oxides by Plants.j—Mr. F. C. Phillips says that the question how far the vital processes of plants are influ- enced by the various mineral compounds presented by the soil to their roots has long been under discussion, but further than to esta- blish the fact that the presence of certain compounds in the soil tends to increase the nutritious elements and promote the growth of particular plants, little has been done towards a complete solution of the problem. It is well known that potash tends to increase the quantity of starch, that silica strengthens the stems of the grasses, that oxide of iron is essential to the production of leaf-green, and that phosphates increase the fertility of the soil for cereals, but even as regards these constant elements of every soil, very little can be positively asserted of the precise influence of any one, in the economy of the plant. Concerning the part played by the rarer elements, cesium, rubi- dium, copper, nickel, manganese, zinc, and barium, in the assimilation of carbon, nitrogen, and the functions of nutrition, and whether they are beneficial or injurious, nothing whatever is known, although modern refinements in chemical methods have led to their frequent detection both in soil and in plants. That so important a problem * Nuoy. Giorn. Bot. Ital., xiv. (1882) pp. 147-55. Cf, this Journal, ante, p. 361. ¢ Journ. Franklin Institute, exiy. (1882) po. 41-9. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 527 should have remained almost wholly unsolved must be attributed chiefly to the very great difficulties which are met in any experimental investigation, but also to the fact that the few investigations published have been carried out, in most cases, for the purpose of proving that vegetation had been injured by metallic compounds traceable to metallurgical works, and with the special purpose of founding a claim for damages, rather than to solve a scientific problem. The study of the influence of metallic compounds on plants has recently acquired great practical importance, from the fact that many manufacturing processes, more especially those employed in the smelting of lead and copper, and arsenical ores of various metals, have given rise to a gradual impregnation of the soil with such metals, and to the conse- quent poisoning of vegetation and animals. The possibility of injury to plants has been denied on the assump- tion that they select such elements of the soil as are nutritious and reject all else. Mr. Phillips has therefore undertaken experiments from which it seems safe to conclude: 1. That healthy plants grown under favour- able conditions may absorb, through their roots, small quantities of lead, zinc, copper, and arsenic. 2. That lead and zinc may enter the tissues in this way without causing any disturbance in the growth, nutrition, and functions of the plant. 3. That the compounds of copper and arsenic exert a distinctly poisonous influence, tending, when present in larger quantity, to check the formation of roots, and either killing the plant or so far reducing its vitality as to interfere with nutrition and growth. In the case of the heavy metals, copper, zinc, arsenic, and lead, it seems to be probable that their oxides may under certain circumstances become deposited in the tissues of the plant. As to the manner in which this takes place, authorities differ. It is supposed by Freytag and others, that plants absorb all soluble matters indiscriminately, through their numberless rootlets; that the absorption of poisonous metals causes no disturbance until a certain degree of concentration is reached, when the plant rapidly withers and dies ; that plants are therefore spared the sufferings of chronic poisoning, but are very susceptible to acute poisoning, which is invariably fatal ; while it is held by others that plants absorb only such elements as are essential and nutritious, refusing to take up what is poisonous or innutritious; metallic compounds found in the analyses are therefore to be traced to atmospheric deposit adhering externally. The theory of Freytag seems to the author to have the weight of facts in its favour, and if it is possible that crops may become charged in this way with poisonous elements of the soil, it becomes a matter of the highest importance that wherever there is danger of such impregnation the most efficient means be employed for its aversion; for soil once impregnated with copper, lead, and zinc, may year after year bear crops poisoned in the same manner. Decomposition of Calcium carbonate in the Stem of Dicoty- ledonous Woods.*—H. Molisch states that the deposition of calcium Pie K. Akad, Wiss. Wien, Ixxxiy. (1881). See Bot. Centralbl., x. (1882) p- 161. 528 SUMMARY OF CURRENT RESEARCHES RELATING TO carbonate in the wood of dicotyledonous trees is not a rare pheno- menon; but that it takes place only in the duramen or in parts of the alburnum which resemble the duramen in properties. In knots and wounded parts it is frequently separated in considerable quan- tities. It is deposited especially in the vessels and tracheides, less often in the libriform, parenchyma, and medullary rays. It occurs abundantly in the pith when the wood that is in immediate proximity — to it assumes the nature of duramen, and becomes filled with lime. An account is given of the different woods in which calcium carbonate was found. Hypochlorin.*—The investigations of Pringsheim + on the nature and mode of formation of hypochlorin have been gone over by A. B. Frank, with the following results :— The hypochlorin reaction is found by Frank to bear the most intimate relation to the presence of the colouring matter of chloro- phyll; and this connection is the only constant one, there being no relation to the presence or absence of conditions of assimilation. Hypochlorin is never present in any other part of the protoplasm than in that which is coloured by the chlorophyll-pigment, and here it appears to be universal, whether the chlorophyll be in the form of grains or spiral bands or in the amorphous condition. The hypo- chlorin reaction manifests itself along with the very first trace of the green colour in the young protoplasm, as was demonstrated in terminal buds of Elodea canadensis, where the cells of the young minute leaves are still in a merismatic condition, long before the differentiation of the chlorophyll into grains, and when it is improbable that any assimilation can take place. Hypochlorin is also found in the cell till the close of the existence of the chlorophyll-pigment, in conditions which exclude the possibility of assimilation. The hypochlorin reaction is invariably accompanied by a destruc- tion of the colouring matter of the chlorophyll. The first effects of acids on chlorophyll-grains is a change of the green colour into yellowish green or yellow, and this is followed by the separation of oily drops of hypochlorin. If, however, the cells are killed, no separation of hypochlorin takes place. Two conditions are therefore necessary for the separation of hypochlorin :—the living condition of the chlorophyll-grain, and the presence of an acid. The reaction may be induced by hydrochloric, sulphuric, nitric, phosphoric, acetic, lactic, tartaric, citric, picric, or salicylic acid, and with very various degrees of concentration. The cause of the change of colour of leaves in autumn is the disappearance of the protoplasm from the cells, in consequenee of which the chloro- phyll-grains come into contact with the acid cell-sap. The same changes take place when leaves become yellow from want of light. The author believes that in this case the chlorophyll is not destroyed directly by the want of light, but only by the secondary action of the acid cell-sap in consequence of the destruction of the protoplasm. * SB. Bot. Ver. Prov. Brandenburg, xxiii. (1822) pp. 11-16. { See this Journal, iii. (1880) pp. 117, 480; i. (1881) p. 479. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 529 In a different communication * J. Wiesner states his general con- currence with Frank’s conclusion, which he would carry somewhat further. From its impermeability to organic acids, Wiesner regards protoplasm as having for one of its functions the protection of chloro- phyll from injury from this source. The same process takes place also in fruits as in leaves. Latex of Euphorbia Lathyris-|—An elaborate examination of the latex of Euphorbia Lathyris has led J. Schullerus to the conclusion that it must be regarded neither as a product of excretion (waste product) nor as a reserve material, but as a substance of actual direct service to the nutrition of the plant. The following are some of the special results at which he has arrived :— The laticiferous tubes of «this plant originate even in the embryo, and exclusively in the cells contiguous to the cortical parenchyma ; no laticiferous cells being formed at a later period or originating in any other way. They are found during the whole life of the plant, and in all its parts, in the root as well as the aerial portion. They may branch, but do not anastomose, either in the nodes or leaves. The growth of these tubes does not depend on that of contiguous cells, but is independent of them and may even be restricted by their growth; they retain, during their existence, their power of apical growth and of branching at any spot. The latex of H. Lathyris is a formative sap, taking part directly in the processes of growth of the plant, and cannot be regarded as a mere reserve material. Its nutritive properties are proportionate to the amount of carbohydrate, especially starch, contained in it. When in an inactive condition it passes over to the state of a primordial latex. This is also the function of the latex of the permanent rhizomes of Euphorbia palus- tris, orientalis, Pithyusa, and trigonocarpa, rich in albuminoids, but containing but little carbohydrate. The absence of this property of storing up reserve materials distinguishes the laticiferous vessels physiologically from the cortical parenchyma. Besides osmotic movement, the latex possesses also a power of movement in mass, corresponding to the general movement of food-materials towards those parts where new formations are taking place, not due in any way to external influences. These facts regarding the physiological function of the latex of E. Lathyris are true also for that of other species of Euphorbia which do not differ from it by any very strongly marked characters. Darwin’s so-called “ Brain-function” of the Tips of Roots.t— E. Detlefsen has investigated in a series of fresh experiments, the peculiar properties attributed by Darwin§ to the extreme tips of * Bot. Centralbl., x. (1882) pp. 260-6. + SB. Bot. Ver. Prov. Brandenburg, xxiii. (1882) pp. 26-93. t Arbeit. Bot. Inst. Wiirzburg, ii. (1882) pp. 627-47. § “It is hardly an exaggeration to say that the tip of the radicle thus endowed, and having the power of directing the movements of the adjoining parts, acts like the brain of one of the lower animals; the brain being seated within the anterior end of the body, receiving impressions from the sense-organs, and directing the several movements,”—Darwin, Zhe Power of Movement in Plants, p. 573. Ser. 2.—Vot. IL. 2N 530 SUMMARY OF CURRENT RESEARCHES RELATING TO roots, and has come to the conclusion that his statement of these properties cannot in all respects be substantiated. He states that the curvatures manifested by the roots when a foreign body is applied to them on one side, and which Darwin attributes to the sensibility of the roots, are really due to injury suffered by the root from the cutting off of free access of air, all the tissues being found to be destroyed up to the cylinder of plerome. That the cause of the curvature is injury to the root-sap is shown by parallel experiments in which the injury is inflicted in other ways. The statement of Darwin that it is only the apex of the root that is susceptible is also contested. Experiments with roots from which the tip had been entirely removed, showed the same geotropic phenomena as others in which the roots were entire. The author further disputes Darwin’s assertion that the apices alone of roots are susceptible to change in the degree of moisture of the environment; he states, on the contrary, that the whole of the growing part of the root, and not merely the tip, is affected by an unequal degree of moisture in the surrounding air, curving in the direction in which the air is most moist. Aerial Cultivation of Aquatic Plants.*—-E. Mer records the results of a series of experiments for the purpose of determining the effects produced by growing in the air plants which ordinarily grow entirely submerged in water. They were placed in a vessel of water in such a way that the buds were above the surface of the water, and the whole covered with a bell-glass ; others being, at the same time, grown under similar vessels entirely in water. The sun, in July, was powerful during the whole of the experiments. In Potamogeton natans and rufescens the shoots grown in the air were distinguished from the normal ones by the shortness of their internodes, the smallness of the leaves, which partially remained rudimentary, and the presence of numerous stomata, which were also found, but in small numbers, in the newly formed branches of the submerged specimens. The formation of stomata is ascribed by the author to the retardation of growth and to heredity. The accumulation of reserve-materials in the tissue resulting from the retardation may bring about divisions in the epidermal cells, and hence lead to the formation of stomata. The formation of stomata only in the parts exposed to air he attributes to more vigorous trans- piration. Similar causes lead to the formation of stomata on the perianth-leaves of P. rufescens and the foliage-leaves of Littorella lacustris. Hereditary tendency causes the localization of the stomata on the upper side of the leaves in P. natans, as is usual in floating leaves; it also produces the effect in Littorella that, when grown in the air, the newly formed leaves possess a larger or smaller number of stomata, according as the plants grew originally at a greater or less depth below the surface of the water. In Hydrocharis morsus-rane the size of the leaves was greatly diminished, as well as the length of the leaf-stalk, the intercellular * Comptes Rendus, xciy. (1882) pp. 175-8. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 531 spaces and epidermal cells were smaller, and the latter had somewhat wavy outlines. In Nuphar pumilum the leaves were smaller and contained less starch. ; The author concludes that the incapacity of certain water plants to produce branches outside the water depends on their inability to resist strong transpiration, and not on any incapacity to grow and nourish themselves in the air. They thrive in the air if it is only sufficiently moist to reduce transpiration to a small amount. Insectivorous Plants.*—A. EF. W. Schimper gives detailed descrip- tions of several insectivorous plants, natives of North America. In the first place, the structure is more fully described than hereto- fore of the ascidiform leaves of Sarracenia purpurea. It was clearly determined that the products of decomposition of the insects and other organic substances found in the pitchers enter the cells of the leaf, as is shown by the changes which take place in the protoplasm of the cells thus affected. In these cells Schimper noticed a pheno- menon closely resembling that described by Darwin as occurring in Drosera under the name “ aggregation of protoplasm.” In fact, how- ever, in Sarracenia, the aggregations consist of a concentrated solution of tannin, which substance is always present in the cell-sap. There occur in North America three species of Utricularia, land- plants growing in moist sandy situations. Of these U. cornuta was especially examined, and presents several very singular points of structure. The plant possesses no true root, the rhizome branching into several root-like organs, which bear the bladders in great quantities, and which the author believes to be homologous to the floating leaves of the aquatic species. The bladders are similar in form to those of U. vulgaris, but want the “antenne,” as is also their histological structure, which is described in detail. They con- tain, besides inorganic bodies, small animals and Alge, especially diatoms, rotifers, and crustacea; the animals were never found alive, but usually much swollen and decomposed, and this was also the case with the diatoms, the contents of the bladders being apparently poisonous to both animals and plants. The hairs of the bladders appear to act as organs of absorption; and in the contents of their cells similar changes were observed to those described in the cases of Sarracenia and Drosera. As in Dionca, an excess of nutriment is injurious to the plant. Climbing Plants.t—In opposition to the view of Von Mohl, S. Schwendener denies the existence of a special faculty of irritax bility to which the twining of climbing stems and tendrils is due. He considers all the phenomena of these organs to be explicable by the laws of circumnutation and of geotropism. Power of Movement in Plants.{—In J. Wiesner’s work on this subject he goes through the results published by Darwin in his work * Bot. Ztg., xl. (1882) pp. 225-34, 241-8 (1 pl.). t SB. Bot. Ver. Prov. Brandenburg, xxiii. (1882) pp. 9-11. { Wiesner, J., ‘Das Bewegungsvermégen der Pflanzen,’ 212 pp., Vienna, 1881. See Bot. Ztg., xl. (1882) pp. 202-8. See also ‘ Nature,’ xxv. (1882) pp. 578-82; 597-601. 2 NZ 532 SUMMARY OF CURRENT RESEARCHES RELATING TO bearing the same title, and in a great many points comes to a more or less different conclusion, his arguments being in all cases founded on actual experiments. The following are some of the more important points in which he differs from Darwin. As regards circumnutation, Wiesner doubts its existence in roots, attributing this apparent phenomenon to the antagonism between geotropism and the natural tendency to curvature existing in roots, first one and then the other of these forces getting the upper hand, and thus moving the tip of the root backwards and forwards. In the case of stems, also, he considers that there are some plants which do not exhibit circumnutation. Some leaves also, he states, grow in absolutely straight lines without circumnutating, the apparent cir- cumnutation being here again due to the varying action of opposing forces, viz. epinasty, apogeotropism, apheliotropism, and gravitation. Wiesner’s explanation of heliotropism agrees with that of De Candolle, that the convex side grows more quickly simply because it is in shade. The author disputes the value of Darwin’s experiments which are alleged to prove the sensitiveness of the tips of radicles, attributing the observed phenomena to injury resulting from the means em- ployed. Electrical Researches on Plant Forms,*—The absorption of water by porous bodies is accompanied by electric currents. When a porous earthenware cell is partly filled with water, and a current completed through a galvanometer by means of electrodes in the water and in contact with the outer wall of the cell, a current passes. The intensity continually diminishes, until it finally ceases, and then a current begins in the opposite direction from the cell-wall through the water. This reversal of current is due to the incomplete state of saturation of the walls of the cell. These phenomena are employed by A. J. Kunkel to account for various electric phenomena observed in plants. In regard to the electromotive action of the upper surface of green leaves, the difference of tension of the various parts was determined by a systematic method of contact over the whole surface, with the result that the leaf-veins are generally positive towards the rest of the leaf, but the direction of the current is reversed if the spot on the leaf where the electrode is placed is wetted before the other electrode is placed on the vein. Also a spot long moistened is positive towards one freshly wetted. When the electrodes rest on the epi- dermis of a plant and a wound is made near the electrode, then that electrode will be negative to the other. The same result is obtained by bending the plant, and the current formed is the more intense the greater the amount of bending, the electrode near the bend being negative to the other. Sometimes plants also show the existence of electric currents, which when the plant moves cause the galvanometer needle to oscillate. * Bied. Centr., 1882, pp. 28-30. Cf. Journ. Chem. Soe. Abstr., xlii. (1882) p. 638. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 533 Electromotive Properties of the Leaf of Dionewa.*—Professor J. Burdon Sanderson has investigated the immediate and subsequent electrical results of excitation of the leaf of Dionea, which have pre- viously been examined by Munk, Kunkel, and the author himself. It is found that at the moment of excitation (whether mechanical or electrical) the under surface of the lobe of the leaf is electro-nega- tive to the upper surface, the difference of potential reaching its maxi- mum about half a second after excitation; it then rapidly decreases until the upper surface is ultimately electro-negative to the lower, and this after-effect remains constant for some time. With a current not much more than adequate, excitation occurs at the moment of closing the current, but none occurs on breaking the circuit unless the current be sufficiently strong. The author considers (1) that the difference of potential is due to the electromotive forces which reside in the living protoplasm of parenchyma-cells in contact with one another, and in ditferent states of physiological activity ; (2) that the second phase of excitation is probably dependent on the diminution of turgescence of the excited cells, arising from a migration of liquid; (3) this explanation cannot be accepted for the phenomena of the first phase, the sudden accession and rapid propagation of which show that it is probably analogous to the “negative variation ” or “ action current ” of animal physiology. Influence of a Galvanic Current on Growing Roots.t—F. Elfving has observed the effect of a continuous current of electricity upon the growing organs of plants, especially roots, and finds that it causes a distinct curvature of the organ in the direction of the positive pole. This curvature has not, however, any physiological significance, like those due to geotropism and heliotropism ; it is due to the retarding effect on growth of the current of electricity, especially on that side of the organ which the current meets directly. B. CRYPTOGAMIA. Cryptogamia Vascularia. Schizeacex.t—The second part of Prantl’s work on the Vascular Cryptogams is devoted to this group of ferns, and especially to the morphology of the non-sexual generation. The first section is occupied with the arrangement of the leaves on the stem and the structure of the leaves and stem. There occur both radial and dorsiventral stems, the most remarkable among the latter being Lygodium, which has a single dorsal row of leaves, this arrange- ment originating even in the growing point. A similar structure occurs also in other ferns. The genus Lygodium is also of special interest with respect to the structure of the sporangia. Each sporangium is here enclosed in a pocket, the upper wall of which is composed of the surface of the leaf * Proc. Roy. Soc., xxxiii. (1882) pp. 148-51. + Bot. Ztg., xl. (1882) pp. 257-64; 273-8. - t Prantl, K., ‘ Unters. zur Morphologie der Gefasskryptogamen. Heft ii. Die Schizeaceen.’ Leipzig, 1881. 534 SUMMARY OF CURRENT RESEARCHES RELATING TO itself, while the lower wall is a lamella of tissue springing from the outer part ofa vein. The sporangium springs, as in Anemia, from the margin of the leaf, while behind the sporangium is formed an annular wall, the indusium, which encloses the sporangium like a hood, the Sporangium becoming eventually placed, in the course of develop- ment, on the under side of the leaf. Such a sporangium, covered by an indusium, is termed by the author a “ monangic ” sorus. The apex of the young leaves is occupied by a wedge-shaped apical cell. In the finer veins the structure of the vascular bundles is collateral. No spiral vessels occur in the stem, and the sieve-tubes are very small. The mesophyll does not possess any true palisade- parenchyma, and is very nearly alike on the two sides of the leaf. The epidermis is not sharply separated from the fundamental tissue. In Anemia and Schizea the cuticle is provided with siliceous warts. In Anemia elegans the stomata occur only on the upper side of the leaf. Those of Schizea are arranged in two longitudinal rows on each side of the veins. As regards classification, Prantl divides the Filices into three primary groups, viz. (1) Hymenophyllacex, Polypodiacee, and Cya- theacesw ; (2) Schizeacex, Gleicheniaceze, and Parkeriacex; and (3) Osmundaces, Ophioglossacerw, and Marattiaceze. Ceratopteris he treats as belonging to the Schizeacez ; it has monangic sori, as also has Botrychium. The author regards the Schizzeacez as presenting the closest affinity among ferns to flowering plants. He inclines to the view that the nucellus of the ovule is homologous to the sporan- gium, and the entire ovule to a monangic sorus with its indusium. Muscinese. Branched Sporogonium of a Moss.*—C. Fehlner describes an instance of branched sporogonium in WMeesea uliginosa. From a common seta spring two sporangia, each with normal operculum and peristome. The capsule of Meesea not being regular, but laterally symmetrical owing to a curvature, the two sporangia are placed back to back in the same plane of symmetry, and the mutual pressure causes the surfaces which are in contact with one another to be some- what flattened. Leitgeb regards this and similar recorded cases of branched sporo- gonium as indicating reversion towards earlier forms of Archegoniatz in which the sporogenous generation is normally branched. He states that they do not result from the archegonium containing two oospheres, or from coalescence of two embryos, but from vertical segmentation of the apical cell of the embryo, which therefore branches when it has attained a certain stage of development. Influence of Light on the Thallus of Marchantia.j —A. Zim- mermann contests Pfeffer’s statement that the development of root- hairs from the gemmz of Marchantia is determined only by contact with the surface of the soil; he finds, on the contrary, that in addition * Oesterr. Bot. Zeitschr., xxxii. (1882) p. 185. } Arbeit. Bot. Inst. Wiirzburg, ii. (1882) pp. 665-9. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 535 to this contact and to gravitation, the absence of light is also a factor in determining on which side of the thallus the root-hairs shall be produced. Precisely the same results were obtained with gemma of LIunularia. The author confirms, on the other hand, the assertion of Pfetier that the organic upper side of the thallus of Marchantia is always the side which faces the light, This was determined by culti- vating the thallus both of Marchantia and Lunularia on the surface of water. He considers these observations to have an important bearing on those of Leitgeb and Prantl* on the bilateralness of the prothal- lium of ferns. Goebel’s Muscineze.{—In his most recent account of the Musci- nex, Dr. K. Goebel introduces no fresh element into the main principle of their classification. The Hepatice are divided into two main groups, the Marchantiacee (subdivided into the Ricciex, Cor- siniez, and Marchantiez) and the Jungermanniacexw (Jungermanniess and Anthocerotez). In the Musci he groups the Sphagnacez and Andreacez together as one type, the Phascacez and Bryinex together as a second type. In each group the various organs are treated in succession :—Firstly, the vegetative organs and the non-sexual mode of reproduction; then the sexual organs, and the development and structure of the second generation, ending with the structure and germination of the spores. A new instance of vegetative budding is described from the calyptra. In their genetic relationship, Goebel regards the Hepatice and Musci as two offshoots from the same stem, the lowest Hepatice pre- senting the nearest resemblance to the original stock. They ma possibly have sprung from the Thallophytes through Coleochete, the hibernating oospore of which presents no great diversity from the sporogonium of Riccia. In the ascending scale the Muscinex have no derivative forms, the series ending with them. Characee. Development of the Cortex in Chara.j—T. F. Allen employs the mode of development of the cortex as a new basis for the classifi- cation of the species of Chara, and distinguishes the following eight methods :— 1. Some species never develope cortex-tubes, and the stems remain naked (C. coronata Ziz.). 2. Some species develope a single cortex-tube, which is so small that it does not join the one from the next leaf (C. inconnexa Allen). 3. Some cortex-nodes develope spines, but no secondary tubes; the primary tubes join and completely encircle the stem (C. crinita Wallr.). 4, Some cortex-tubes show a partial development of secondary tubes (C. evoluta Allen). * See this Journal, ii. (1879) p. 917; iii. (1880) p. 121. + Goebel, K., ‘Die Muscinex.’ Encyklopedie der Naturwissenschaften, Ite Abtheil. 28 Lief. pp. 315-401. ¢ Bull. Torrey Bot. Club, ix. (1882) pp. 37-47 (8 pl.). 536. SUMMARY OF CURRENT RESEARCHES RELATING TO 5. Some cortex-tubes develope one secondary cell only, which becomes as long as the primary cell, but is of smaller diamet>r (C. excelsa Allen, C. intermedia A. Br., C. contraria A. Br. Sect. Tyla- canthz). 6. Some develope only one lateral cortex-cell, which becomes larger than the primary cell and partially covers it, so that the primary cell seems to lie in a furrow (C. fetida A. Br. Sect. Aula- canthee). 7. Some cortex-cells develope perfectly one lateral cell, and im- perfectly another (C. aspera Willd.). 8. Some cortex-cells develope perfectly both lateral cells, so that three complete series of cells arise from each leaf (C. fragilis Desv., C. gymnopus A. Br.). Details of the application of these characters are followed by full descriptions of the following new American species :—C. imconneaxa, evoluta, and excelsa. Fungi. Ustilaginese.*—The fifth part of De Bary and Woronin’s ‘ Morpho- logy and Physiology of Fungi’ is occupied by a treatise on the Ustilagineze by M. Woronin. The first section consists of a complete life-history of Tuburcinia Trientalis Berk. and Br., which attacks the stem, leaves, and rhizome of Trientalis europea. The mycelium consists of sparingly septated and irregularly branched hyphe which permeate the intercellular spaces, and put out haustorial lateral branches into the cells them- selves of the host; these branches, with their short irregular secondary branches, having somewhat the form of a bunch of grapes. On this mycelium are produced two kinds of reproductive organ, conidia and resting-spores. ‘The conidia are always borne on the under side of the leaves of the host, and form a white mould-like coating, the Ascomyces Trientalis of Berk. The hyphe on which they are borne form a more or less dense felt between the epidermis and the meso- phyll; lateral branches then penetrate through the stomata or between the walls of the epidermal cells, and bear the pear-shaped conidia, either first putting out haustoria or not. The conidia germinate readily in water, putting out a germinating filament, which either at once developes a conidiophore, or continues to grow without putting out conidia. Conidial hyphz are also produced by sowing conidia on moistened leaves of Trientalis, These give rise to small patches of mycelium, on which the resting-spores are developed. The resting-spores form brown Sorosporium-like masses, dusky patches $-2 mm. in diameter, on the leaves and leaf-stalk of the host. These spores are produced on much-branched mycelial filaments, which appear usually to be of smaller diameter than the purely vege- tative ones, to be more freely septated, and usually destitute of haustoria. In their youngest stage they have the form of straight or curved, spiral or twisted branches, either singly or in coalescent * De Bary, A., u. Woronin, M., ‘ Beitrage zur Morph, u. Phys. der Pilze,’ Part v. 35 pp. (4 pls.), 4to, Frankfurt a, M., 1882. is ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 5387 pairs. These become septated, and some or all of the cells become vesicular. Soon a number of these hyphe amalgamate into a dense ball, the vesicular cells at the same time increasing in size. In this way is formed a fructification, the interior of which is composed of the spores, polyhedral cells with ultimately thick and brown walls, com- paratively large and numerous (as many as 100). The filamentous envelope of hyphe ultimately gelatinizes and disappears. The process agrees in essential points with that in Sorosporium Saponarie. The resting-spores do not remain dormant through the winter, but germi- nate late in the autumn of the same year on the host, each of the spores germinating separately. The process corresponds to that in Tilletia, each spore putting out a promycelium, which forms at its apex a cluster of cylindrical-fusiform sporidia in groups of from four to eight. While they are being formed the protoplasm leaves the basal part of the promycelium, and becomes separated by a septum from the empty portion, the promycelium thus becoming bicellular. The sporidia are abstricted from the terminal cell, which Woronin calls the basidial cell, and compares with the basidium of the Basidiomy- cetes. Unlike Tilletia, it becomes completely detached from the other cells. Two sporidia frequently anastomose, a process which Woronin regards as one of conjugation. One of the conjugating sporidia de- velopes at its apex a secondary fusiform sporidium ; but this also takes place in those which do not conjugate. They may even produce tertiary sporidia. After the sporidia have become detached, the basal cell, if still containing protoplasm, may put out a germinating tube. The sporidia and conidia bear no resemblance to one another in form. The sporidia are carried to the ground by rain or dew, and in this form again reach the leaves or stem of the host, which they penetrate with their mycelia. In the second section, the author describes the mode of germina- tion of the spores of other species of Ustilaginex, which frequently differs in minor points from that of Tuburcinia, viz.:—Sorosporium Saponarie, Tolyposporium Junci, Thecaphora hyalina, Entyloma Ascher- sonii, E. Magnusii, and Melanotenium endogenum. In the third section these results are compared, and the group classified according to the mode of germination, as follows :— I. No sporidia are formed in germination. a. The spores put out long and copiously septated germinating filaments, which either are unbranched or the upper protoplasmic cell puts out lateral irregularly distributed branches. The terminal cell sometimes becomes detached, and carries on an independent existence—Sorosporium. b. The growth of the germinating filaments is limited, and they form a promycelium. They are septated, but instead of producing sporidia, put out filaments, which usually grow in opposite directions, and which conjugate at their apices, then developing the true germi- nating filament—Thecaphora. Il. The promycelium is septated into a number of cells, from each of which is abstricted one or more sporidia :—Ustilago-Schizonella (S. melogramma DC.), Tolyposporium. 538 SUMMARY OF CURRENT RESEARCHES RELATING TO TII. At the apex of the promycelium is formed a whorl of from two to eight usually fusiform branches, also termed sporidia, which usually conjugate in pairs, developing finally into secondary sporidia or directly into long, slender, simple or branched germinating fila- ments : — Tilletia, Entyloma, Melanotenium, Schroeteria, Urocystis, Tuburcima. The following species, nearly allied to Tuburcinia, are also specially described :—Thecaphora aterrima Tul., Sorosportwm schizo- caulon Ces., S. Miillerianum Thiim., Urocystis Paridis 'Thiim. (Soro- sporium Paridis Wint., Polycystis opaca Strauss, Urocystis Colchici f. Paridis ¥. vy. Waldh.), Tuburcinia Veronice Schrot., T. Cesati Sor., T. scabies Berk. Unobserved Sensitiveness in Phycomyces.*—F. Elfving has ob- served that if a moist disk of gypsum is brought near to growing Phycomyces, the sporangiophores will lose their upright growth and bend in various directions; and this will take place even if the atmosphere is saturated with aqueous vapour. The author suggests that the phenomenon is due to contact electricity. Beltrania, a New Genus of Hyphomycetes.t—Under the name Belirania rhombica O. Penzig describes a hyphomycetous fungus con- stituting a new generic type, found on the under side of fallen lemon leaves in Sicily, on which it forms an olive-coloured velvety coating. It presents most affinity to Fusicladiwm and Scolecotrichum, but differs from them in having sterile filaments in addition to the sterigmata, and the bicellular beaked spores collected in clusters on short basidia. The following is the technical description of the genus :— Cespitulis hypophyllis, stratum fusco-olivaceum constituentibus ; hyphis erectis vel adscendentibus, dense aggregatis, continuis vel 1-2-septatis, subsimplicibus, sinuosis; setulis sterilibus longioribus inter hyphas fertiles intermixtis; conidiis vel in hypharum apice sessilibus vel sterigmate ex apice oriundo suffultis, solitariis vel fasciculatis, 1-septatis, apice rostratis. Chemical Composition of Moulds.{—N. Sieber has prepared a srowth of pure Aspergillus, Mucor, and Penicillium, the absence of Schizomycetes being assured by the presence of free phosphoric acid in the nutrient fluid. An analysis of the alcohol and ether extract, of which the exact composition is given, showed that it consisted entirely of albumen and cellulose. Further experiments show that the form of albuminoid present was not that of mycoprotein. A very small quantity of an undetermined substance crystallized out of the extract. Salmon Disease.S—Professor T. H. Huxley, in his observations on this disease, not only examined the minute structure of both the healthy and diseased skin, but also tried some experiments on the * Bot. Notiser, 1881. See Bot. Centralbl , x. (1882) p. 76. + Nuov. Giorn. Bot. Ital., xiv. (1882) pp. 72-5 (1 pl.). { Journ. f. prakt. Chem., xxiii. (1881) pp. 412-21. § Proc. Roy. Soc., xxxiii. (1882) pp. 381-9. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 539 transplantation of the Saprolegnia of the living salmon to dead animal bodies. The body of a recently killed common house-fly was gently rubbed two or three times over the surface of a patch of the diseased skin of a salmon, and was then placed in a vessel of water, on the surface of which it floated, in consequence of the large quantity of air which a fly’s body contains. In the course of forty-eight hours, or thereabouts, innumerable white cottony filaments made their appearance, set close side by side, and radiated from the body of the fly in all directions. As these filaments had approximately the same length, the fly’s body thus became enclosed in a thick white spheroidal shroud, having a diameter of as much as half aninch. As the filaments are specifically heavier than water, they gradually overcome the buoyancy of the air contained in the trachee of the fly, and the whole mass sinks to the bottom of the vessel. The filaments are very short when they are first discernible, and usually make their appearance where the in- tegument of the fly is softest, as between the head and thorax, upon the proboscis, and between the rings of the abdomen. These fila- ments, in their size, structure, and the manner in which they give rise to zoo-sporangia and zoospores, are precisely similar to the hyphe of the salmon fungus; and the characters of the one, as of the other, prove that the fungus is a Saprolegnia and not an Achlya. Moreover, it is easy to obtain evidence that the body of the fly has become infected by spores swept off by its surface when it was rubbed over the diseased skin. These spores have in fact germinated, and their hyphe have perforated the cuticle of the fly, notwithstanding its comparative density, and have then ramified outwards and inwards, growing at the expense of the nourishment supplied by the tissues of the fly. This experiment, which has been repeated with all needful checks, proves that the pathogenic Saprolegnia of the living salmon may become an ordinary saprogenic Saprolegnia ; and, per contra, that the latter may give rise to the former, and they lead to the important practical conclusion that the cause of salmon disease may exist in all waters in which dead insects, infested with Saprolegnia, are met with ; that is to say, probably in all the fresh waters of these islands, at one time or another. On the other hand, Saprolegnia has never been observed on decaying bodies in salt water, and there is every reason to believe that as a saprophyte, it is confined to fresh waters. Thus it becomes, to say the least, a highly probable conclusion that we must look for the origin of the disease to the Saprolegnie which infest dead organic bodies in our fresh waters. Neither pollution, drought, nor overstocking will produce the disease if the Saprolegnia is absent. The most these conditions can do is to favour the development or the diffusion of the materies morbi where the Saprolegnia already exists. The results of the last season’s observations on the salmon disease appear to justify the following conclusions :— 1. That the Saprolegnia attacks the healthy living salmon exactly 540 SUMMARY OF CURRENT RESEARCHES RELATING TO in the same way as it attacks the dead insect, and that it is the sole cause of the disease, whatever circumstances may, in a secondary manner, assist its operations. 2. That death may result without any other organ than the skin being attacked, and that, under these circumstances, it is the conse- quence partly of the exhaustion of nervous energy by the incessant irritation of the felted mycelium with its charge of fine sand, and partly of the drain of nutriment directly and indirectly caused by the fungus. 3. That the penetration of the hyphe of the Saprolegnia into the derma renders it at least possible that the disease may break out in a fresh-run salmon without re-infection. 4, That the cause of the disease, the Saprolegnia, may flourish in any fresh water, in the absence of salmon, as a saprophyte upon dead insects and other animals. 5. That the chances of infection for a healthy fish entering a river are prodigiously increased by the existence of diseased fish in that river, inasmuch as the bulk of Saprolegnia on a few diseased fish vastly exceeds that which would exist without them. 6. That as in the case of the potato disease, the careful extirpation of every diseased individual is the treatment theoretically indicated, though, in practice, it may not be worth while to adopt that treat- ment. Formation of Saccharomyces in Nutrient Fluids containing various Proportions of Nitrogen.*—M. Hayduck finds asparagin especially well adapted as a source of nitrogen for Saccharomyces. The mineral ingredients of the nutrient fluid were a mixture of 50 g. acid potassium phosphate, PH,KO, and 17 g. crystallized magnesium sulphate; and the following results were obtained :— 1. The nitrogen contained in a nutrient fluid is assimilated by the yeast only up to a certain degree of concentration ; and above this limit the nitrogen is not used in the production of yeast. (2) In all the experiments an excretion of nitrogen was observed. (3) When formed in very dilute solutions the yeast contains a constant minimum proportion of nitrogen; as the proportion of nitrogen in the solution increases, the amount of yeast formed remains the same, while the proportion of nitrogen in it increases. But beyond a certain limit, the amount of nitrogen in the fluid increases neither the amount of yeast produced nor the proportion of nitrogen in it. (4) The fer- menting power of the yeast depends partly on the proportion of nitrogen contained in it. (5) Yeast containing a large amount of nitrogen can increase in a pure solution of sugar, a portion of the nitrogenous contents of the mother-cells being used in the formation of the daughter-cells. (6) The growth of the yeast may be affected by the formation of one or more products of fermentation, alcohol especially exerting a prejudicial influence upon it. * Zeitschr. f. Spiritusindustrie, 1881, p. 173. See Bot. Centralbl., x. (1882) p- 153. * ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 541 Morphology and Genetic Relationship of Pathogenous Bacteria,* —Dr. T. Haberkorn thus sums up the results of a series of observa- tions on this subject:—(1) The four tribes of Cohn, spherobacteria, microbacteria, desmobacteria, and spirobacteria, cannot be maintained ; these being all forms of a single genus with numerous species. (2) The history of development of the bacteria of malaria, typhus, and acute contagium is essentially the same, including pleomorphy and a definite alternation of generations. (3) Each of these diseases is accompanied by a distinct species of bacterium; typhoid having also one of its own. (4) The various species of bacteria are dis- tinguished by. their conditions of existence, ‘size, colour, habit, movements, and metastasis. Pathogenous Bacteria.j—V. Babes has convinced himself that there are no bacteria in the blood or the tissues of healthy men ; this judgment is based on the personal examination of more than one hundred bodies. He once observed the growth of filaments of Bacillus anthracis from spores in the sexual organs of a woman. Bacterian colonies, and not rods only, were observed in a case of Anthrax intestinalis; other examples of similar phenomena were observed, and weaken the generally accepted doctrine that rods alone are found in the living body. The author has for a long time used aniline green and aniline violet as colouring agents. Bacterium of Charbon.{—The temperature which seems most favourable to the bacterium of charbon, is that of mammalia (37° C.). Birds, having a higher temperature (about 42°), do not take the disease under ordinary conditions. Pasteur, however, has developed it in fowls by lowering the temperature (keeping the feet in cold water). M. Gibier has now experimented with frogs, and finds that they- do not suffer after inoculation in the normal state; but if kept, after being inoculated, in water at about 37°, they may take the disease (five out of twenty did—most of the others died soon after immersion). The bacteria developed were remarkable for their great length, and this is attributed to the slowness of the circulation. Connection of Bacteria with Ferments.§—J. Rossbach finds that the death which ensues in one to two hours after the injection of papayotin into the rabbit is accompanied by the appearance of large quantities of bacteria in the blood. These were ascertained to be entirely absent before the injection; but introduction of as small quantities as 0°05 to 0-1 gramme of this substance resulted, after death, in the presence of a large number of moving globular and “ hour-glass-shaped ” bacteria in every drop of blood taken from the heart. Thus it appears that the presence of a small quantity of an unorganized and purely chemical substance is sufficient to produce in the body conditions which induce the rapid multiplication of micro- phytes already existing there in insignificant quantities. This * Bot. Centralbl., x. (1882) pp. 100-6. t Biol. Centralbl., ii. (1882) pp. 97-101. $~ Comptes Rendus, xciv. (1882). § Medic. Centralbl., xx. (1882) p. 81. Cf. Naturforscher, xv. (1882) p. 224. 542 SUMMARY OF CURRENT RESEARCHES RELATING TO supports the view that chemical poisons or ferments play an important part in the injections connected with organic germs. Lichenes. Life-history of Cora.*—The genus Cora, established by Fries, has been regarded by some as belonging to Algez, by others as belong- ing to Fungi, while Nylander, who detected the true fructification as consisting of apothecia and ascospores, maintained it to be a lichen. O. Mattirolo has carefully examined all the known species, and fully confirms Nylander’s view. In the thallus is a well-defined gonimic layer, the gonidia belonging to the genus Chroococcus. One species, Cora ligulata Kremp., must be erected into a distinct genus in which the gonidia have a Scytonema-form ; Mattirolo proposes for it the name Bhipido- nema. 'The author has not been able to confirm Nylander’s account of the occurrence of apothecia, which probably belonged to a different lichen or fungus. Both Cora and Rhipidonema have on the under side a true hymenium, something like Thelephora or Kneiffia, formed of basidia which are the apices of special hyphe. Hach basidium bears a sterigma, on which is a single spherical spore, as in Kneiffia. The author holds, therefore, that we have in these two genera lichens in the building up of which Basidiomycetes, and not Ascomy- cetes, have taken part. This new group he terms HymEnonicHEnns, and places them among the Basidiomycetes, near to Kneifia, Corticium, Stereum, Thelephora, and Hypochnus. It includes the following species: —Cora Pawonia, glabrata, gyrolophia, and Neesiana, and Bhipidonema ligulata. They are all extra-Kuropean, and abundant in the tropics. Minks’s Licheno-mycological Symbols.j—In his last essay on the structure and affinity of lichens, Dr. A. Minks recapitulates the grounds of his microgonidial theory,{ and recommends Leptogium myochroum as a specially favourable species for establishing the existence of microgonidia. The ascus of a lichen he regards as simply a highly differentiated hypha, the terminal cell of which has the power of dividing so as to produce the spores. Neither in the history of their development nor in their structure do the spores correspond to the ascospores of the true Ascomycetes; and their mode of germination is also different. The portion already published of Dr. Minks’s work includes descriptions of 170 species ; and the whole family is intended to be gone through at the rate of about 200 species per annum. Alge. Symbiosis of Alge with Lower Animals.§—Since so many naturalists have published observations on this subject, Dr. G. Entz * Nuoy. Giorn. Bot. Ital., xiii. (1881) pp. 245-67 (2 pls.). + Minks, A., ‘Symbolee licheno-mycologice,’ Part I. Cassel, 1881. t See this Journal, ii. (1879) pp. 311, 931. § Biol. Centralbl., i. (1881) p. 646. Cf. Naturforscher, xv. (1882) pp. 93-4, and this Journal, ante, p. 241. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 543 takes occasion to call attention to some results of his own, published in Hungarian in 1876. From a study of the chlorophyll-bodies of Infusoria, he had come to the conclusion that their presence there was not distinctive of any special group of Infusoria. These bodies only occurred in omnivorous species; and those species in whom they occurred in abundance were noticed to take in no solid food, but only to agitate water in their cesophagus. He characterized these green bodies as Alge, and stated their relation to their hosts as being a perpetual source of nutriment to the latter, which in their turn furnish them with a safe domicile; the Infusorian supplies the alga with carbonic acid, while the alga produces oxygen for its host. “We have thus to do in this case with a fellowship or peculiar consort relation between two totally different organisms, which may be compared in some respects to the organization of the lichens, which, according to Schwendener’s interpretation, owe their existence to the association of a fungus with an alga.” Entz has subsequently continued his study of this question, and has been able clearly to see a nucleus in these chlorophyll-bodies, and to determine that the mass is generally invested by a hyaline gelatinous envelope, and thus exhibits all the characteristics of the Palmellacee. He finds that the zoospores of various low Alge and green Flagellates as well may become converted into these ‘‘ pseudo-chlorophyll-bodies.” Division of the Cell-nucleus in Spirogyra.*—I. Tangl gives the following results of observations on an undetermined species of Spirogyra :— 1. The membrane of the cell-nucleus, when at rest, has a reticulate structure; but the author was unable to determine whether this was the result of local differences in density, or of actual perfora- tion. 2. The nucleus contains, as a rule,only a single nucleolus, and includes, when at rest, besides the nucleolus, a finely granular mass, very poor in substance, and only slightly tinted by colouring re- agents; the nucleolus is bounded by a membrane which is not tinted. 3. The nuclear spindle, the formation of which is preceded by demonstrable changes in the contents, is of the type described by Strasburger, and consists of equatorial rod-like elements which are not separated. 4, The portion of the original contents present in the “ spindle- stage” of the nucleus, and only slightly tinted by reagents, is subsequently resorbed during the formation of the daughter-nuclei. 5. These facts appear to corroborate Strasburger’s view that the spindle-fibres are derived from the protoplasm which is forced into the nucleus. 6. During the separation of the two halves of the nuclear plate a uniting tube is formed, proceeding from the membrane of the nucleus which is already perforated at the two poles at the “ spindle- * Anzeiger K. Akad. Wiss. Wien, March 30, 1882. See Bot. Centralbl., x. (1882) p. 189. 544 SUMMARY OF CURRENT RESEARCHES RELATING TO stage,” and the enveloping membrane of the nucleolus, the inner surface of which is closely applied to the uniting threads. 7. This combining tube constitutes the lining of an internal cavity of the mother-cell, which is relatively very large at a certain stage of the division, and which is closed outwardly by the rudiments of the daughter-nuclei. The further behaviour of this tube corre- sponds to that of the uniting threads in the species described by Strasburger. Batrachospermum.*—G. Arcangeli describes in detail several species of Batrachospermum, among them one new one, B. Julianum, found in thermal waters near Pisa. He describes the genus as pre- senting, in the same species, two modes of multiplication of cells, by segmentation and by gemmation. The former occurs in the terminal cell of the stem and of the primary branches, and is the mode by -which these organs lengthen, also in the cortical branches; while the verticillate branches are formed and lengthen by gemmation. Ata short distance from the terminal cell of the stem and of the primary branches, the rudiments of the verticillate branches make their appearance in the form of hemispherical protuberances, which separate themselves from the mother-cell by means of a tangential septum. B. Julianum differs from the other species in the mode of develop- ment of the female organ, presenting a considerable resemblance to that in Nemalion; and the author considers that it establishes an intimate relation between the mode of fertilization in Batracho- spermum and in the Florides. Although the thermal water in which B. Julianum grows, produces also a species of Chantransia, he was unable to detect any genetic connection between these genera, as stated by Sirodot. New Beggiatoa.t—A. Engler has observed the barren salt ground in the neighbourhood of the harbour at Kiel to be densely covered with the dusky white filaments of several species of Beggiatoa, especially B. alba Vauch. var. marina Cohn (B. Cirstedii Rabenh.). Attached to the legs of crabs in the deep water of the same harbour he finds a new species, not corresponding completely to any hitherto described, which he calls Beggiatoa multiseptata. Associated with it is another form, resembling Cladothrix, but not belonging to the Schizomycetes, which Engler regards as the type of a new genus, and names Cladomyces Mebiusii. It must be placed near Stigeoclonium. Vampyrella.t—J. Klein attempts to answer the question whether this organism is animal or vegetable, and has for this purpose examined four species, three of them new, Vampyrella variabilis, inermis, and pedata. In the resting condition Vampyrella forms, according to the species, stalked or sessile capsules, attached to various fresh-water Algz. A more exact description is given of V. variabilis, which occurs in * Nuov. Giorn. Bot. Ital., xiv. (1882) pp. 155-67 (2 pls.). + SB. Bot. Ver. Prov. Brandenburg, xxiii. (1882) pp. 17-20. + Bot. Ztg., xl. (1882) pp. 193-200, 209-17 (1 pl.). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 545 the form of globular, ellipsoidal, or irregular cysts in the empty cells of fresh-water conferve. When ripe the contents are reddish, orange- yellow, or bright red, including a dark spot. The endochrome sub- sequently escapes in two, four, or more masses, which, as they gradually escape from the cyst, are clothed at the edge with a fringe of cilia, the dark body remaining still enclosed within them. The escaped ciliated bodies must be regarded as zoospores, and are provided with pseudopodia, moving about slowly with an amceboid motion. When two meet, and their pseudopodia come into contact, they slowly coalesce, and this the author regards as a kind of conjugation. The resulting bodies appear to be of the nature of plasmodia, are endowed with a creeping motion, and may again coalesce. These larger bodies attach themselves to certain alg, ultimately become encysted, and then again go through the same course of development. Those zoospores which do not conjugate also become eventually encysted. Attached to the conferva are also found cysts of the Vampyrella of a different kind, resting cysts which remain for a time in a dormant condition before any further development takes place. Vampyrella pendula and inermis agree with V. variabilis in essential characters, while V. pedata differs in some important points, and may, perhaps, be the type of a distinct genus. It is found, like the two last species, attached to Cidogonium; its zoospores have neither cilia nor pseudopodia, but a long projecting colourless beak, which is in front during the motion of the body, and appears to guide its movement by bending in different directions, finally becoming encysted, apparently without conjugation. These bodies have been described by zoologists as rhizopods (Hyalodiscus rubicundus Hertwig and Lesser, and Plakopus ruber F. E. Schulze). A full description follows of seven distinct species of the genus ; and the author concludes, taking all the points of structure into con- sideration, that Vampyrella is most nearly allied to the Chytridiacez and Myxomycetes, and must be regarded as a plant; but that it exhibits in some respects a transitional character to the animal kingdom. Schizophycex.*—W. Zopf has undertaken a fresh examination of the lowest forms of Algz, with the special object of determining whether the filamentous forms Scytonemee, Oscillaries, &c., and the non-filamentous or Chroococcacee may be different stages of develop- ment of the same organism. Pure material was obtained by allowing the filaments of the alga under examination to creep along the wall of the vessel, and collect above the level of the water in tufts or pellicles. These were then cultivated in boiled water or on disks of porous clay, which had also been exposed to a high temperature, and placed in large glass vessels in moist boiled sand. The dead cells of water-plants, as Lemna, Utricularia, &c., and the shells of certain of the lower animals, like Cypris, were also used as nurseries for the filamentous Schizophycee, and in them the formation of chroococ- caceous forms was especially well followed out. * Bot. Centralbl., x. (1882) pp. 32-6. Ser. 2.—Vot. II. 20 546 SUMMARY OF CURRENT RESEARCHES RELATING TO The author describes in detail the development under these circumstances of nine different filamentous species; and arrives at the following general conclusions:—(1) That the relationship between the Schizophycee and the Schizomycetes is much closer than has hitherto been generally believed, confirming the classification adopted by Cohn and Sachs of including these two families in the same group of Schizophyta. (2) That a new impulse is thus given to the study of the Schizophycee. (8) That the formation of zooglea is a more widely spread phenomenon than has hitherto been supposed, as is illustrated in Cienkowski’s observations on Ulothriz, Cylindrocapsa, and Gleothamnion. The results obtained tend also to the conclusion that many other members of the group of Chroococcacee are merely stages of development of filamentous Schizophycee. Motion of Diatoms.—Prof. Hamilton L. Smith considers* that Mr. C. M. Vorce’s paper on this subject t is marked by careful, well- matured statements, and that the conclusions at which he has arrived are quite correct. He has not the least doubt that the diatoms are enveloped by a membrane, out of which the stipes, tubes, &c., are formed. “'The movements, so curious and so varied, are yet con- nected with the structure of the frustule, and we must not ignore this in attempting to explain them, e.g. the Nitzschie, which have a con- tinuous raphe, that is, without median nodule or break, move in the most lively manner, they are also long and slender; the stalked forms move when free, Cocconema, for example, in a long curve, Gompho- nema, straight ; the Navicula group move in straight lines, but not in so lively a manner as the Nitzschiw. All these, except the last named, have a median nodule. The Surirellew, which have the raphe along the four expansions, or ale (two for each valve), move more sluggishly, rolling over frequently, and the Amphiproree and other twisted forms rock or twist as mentioned by Mr. Vorce, while the circular forms, like Coscinodiscus, which have the raphe probably all round the margin of the cingulum or connecting zone and edge of the valve, do not move at all, or if so, very sluggishly. The movement then is more or less regulated by the structure of the frustule, and in any explanation we must not forget this. The careful observation of facts meanwhile should not be neglected, and the publication of them may give the clue or hint that will guide some other observer, possibly, to the true solution of a phenomenon as marvellous as it is at present inexplicable.” * Amer. Mon. Micr. Journ., iii. (1882) p. 85. t See this Journal, ante, p. 394. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 547 MICROSCOPY. a, Instruments, Accessories, &c. Lossner’s Tele-microscope.*—O. M. Lossner has patented an instrument under this name. The objective forms a reduced image of a somewhat distant object, and this is enlarged by an ocular of four lenses. The construction of some is in hand, and “if suc- cessful this instrument, even if only for small enlargements, will, without doubt, be a welcome tool for the observation of living insects, &e.” Prazmowski’s Micrometer Microscope.— This Microscope (Fig. 91) was designed by M. Prazmowski for investigations in Fic. 91. “teen th Sl ——-+ ai en iis 1 iat te Rix, = —— er which measurements are to be recorded, and when it is also required to note precisely the angle of the illumination, &c., for purposes of repetition. We believe that it was made upon a special order (and not subsequently reclaimed), so that M. Prazmowski must not be * Centr.-Ztg. f. Opt. u. Mech., iii. (1882) p. 108. 0 548 SUMMARY OF CURRENT RESEARCHES RELATING TO considered as endorsing any practical value in the instrument as a whole. The principal micrometric movement is controlled by the gradu- ated milled head A working on a fine steel screw against springs, by which the rectangular framework carrying the optical body is moved in a direction at right angles to the vertical main limb and parallel with the stage. The optical body, with rack and pinion for coarse adjust- ment, fits loosely into this carrier ; it can be adjusted concentrically with the rotating stage by the action of side screws together with the micrometer-screw at A, and can be clamped in position by a screw- collar beneath. The fine-focussing is effected by the micrometer-head B working on a screw against a spiral spring on the main limb; the whole of the optical portion is thus moved together in focussing, as 1s usual in Continental Microscopes. ‘The eye-piece has a goniometer circle C attached, and is provided with a movable disk of glass with crossed lines in the usual position of the eye-piece micrometer, by which accurate determinations of angles in azimuth can be made while the object is stationary, &c. The rotating stage is of simple construction, similar to that on ordinary “turntables”; it is held in position by an indented key-piece (metal knob shown under stage) that slides into a circular rotating groove beneath, and can be removed at pleasure—the main rectangular stage is then only =3,th inch in thickness, and is fitted with a wheel of diaphragms, also removable. The mirror D is mounted in a gimbal sliding on a bar with lateral motion ; the three axes of motion are each provided with a graduated disk and pointer, so that exact record of the position can be made. The condenser E. is mounted to slide on one of the feet, and can be adjusted variously to direct the light upon the mirror. The two back feet close up against the front one for convenience of packing. Simplified Reading Microscope for horizontal and vertical circles.*— Herr Hensoldt, of Wetzlar, claims to have made a great-im- provement in the application of the compound Microscope toinstruments of medium size, such as theodolites of from 12 to 20 em. in diameter of limit. Whilst universally used for the larger, especially astrono- mical instruments, a Microscope has been found to be inconvenient for others, principally on account of the projecting micrometrical screws and the length of the body hitherto found necessary. The author says that he “has succeeded in reducing the length of the Microscopes to a most considerable extent by the selection of favourable qualities of glass, and by suitable construction of the lenses. With a power of from 45 to 50 diameters, they only possess a length of 5 cm. and an outer diameter of 16 mm., reading up to 12, and between the objective and the division there is suffi- cient room to affix a little illuminator, which throws a more than sufficient amount of light on the division. The latter appears very clear and distinct, and if the limb is provided with a glass cover, the objectives of the Microscopes are constructed accordingly, so as not to lose in definition. * Zeitschr. f. Vermessungswesen, viii. Transl. in Eng. Mech., xxxiv. (1881) pp. 83-4 (1 fig.). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 549 “The Microscopes are provided with adjustable eye-pieces, to render the division of the micrometer distinct for every eyesight, and at the lower end is a short draw-tube, by means of which a small alteration in the magnification can be effected, whereby the intervals of the micrometer (previously determined by calculation) can be brought to accurately harmonize with the division of the circle. “ As the field of view, though as extensive as possible, cannot be so large as to always include figures of the divided circle, an index with a magnifying lens must be fixed at any desired point, by means of which the reading of the angle up to the nearest division of the circle is obtained, while the determination of the excess is effected by the Microscopes.” The divisions of the circle with which the Microscopes are used are not carried to any great degree of minuteness. The degrees are, for instance, divided into sixths, or 10',and the micrometer consists of ten equal divisions, representing, therefore, minutes, and the latter can then be mentally subdivided with great facility. An important advantage is, the author considers, obtained by the small number of graduations of the micro- ate ae meter, which permits an ae easy, rapid, and accurate reading, which does not occupy so much time as in the case of verniers. Swift's. Tank Micro- scope.—This, Fig. 92, con- sists of the stand of a bull’s- eye condenser to which are attached two additional short arms, the upper one carrying the microscope- tube and the lower a re- volving cork-holder and forceps for flowers or other objects suitable for low powers. The tube has a rack-and-pinion movement and the arm to which it is attached can be raised or lowered on the standard —_— and clamped in any posi- == tion. The tube can also be rotated on the arm so as to be either vertical or horizontal, or it can be removed from the arm altogether. Teasdale’s Field Naturalist’s Microscope.—This (Figs. 93 and 94) is made by Messrs. Field of Birmingham, and was designed by Mr. W. Teasdale with the view of providing the working microscopist with a really cheap and efficient dissecting Microscope, and it may be readily certified that it fully accomplishes these objects. “It is so simply and substantially made that it * - 550 SUMMARY OF CURRENT RESEARCHES RELATING TO im . Fic. 93. i) ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 551 may be used by an intelligent child, as well as by the experienced microscopist. It was termed a ‘Field Naturalist’ rather than a ‘Dissecting’ Microscope to disarm the suspicion with which some people look upon an instrument with the latter name as a rack or means of torture for frogs, &e.” The woodcuts render any detailed description of the instrument unnecessary, and we need only call attention to the sloping rest for the hands and that there are three lenses, a condensing lens, forceps, and live-box. The lenses drop into the arm which carries them, and also into each other, so that they may be used in combination, producing seven powers in all. Marshall’s turntable can also be used with the instrument, the spindle passing through a hole in front of the stage, and its point revolving in a brass socket below. Steinheil’s Achromatic Eye-pieces.— These eye-pieces (?in. and } in.), exhibited and described by Mr. Ingpen at the June meeting of the Society, are shown in Figs. 95 and 96 in section. They are especially adapted for micrometry. They consist of a double convex lens of crown between two meniscus lenses of flint, all cemented together. Grooves cut in the edge and blackened, form diaphragms as in the Coddington lens, New Combination for Objectives.*—The following is the whole of the note by C. V. Zenger under this heading published in the ‘ Comptes Rendus’ :— “The author proposes to obtain an amplification equal to 2000 with a large focal distance. It would then be possible for anatomists and physiologists to carry on their dissections and preparations with a very considerable amplification, at a distance from the objective equal to 4 mm. or 6 mm.” Fluid for Homogeneous Immersion.t—Professor Abbe finds that pure cedar-oil may be prepared so as to render it much less fluid than in its ordinary condition. By spreading it out in thin layers and exposing it for a long time to the influence of air and light, it becomes of the consistency of castor-oil, and without any increase in dispersive power, its refractive index is raised to 1°518-1°520. If desired, the index can of course be reduced to 1-510 by the addition of olive or castor oil. Dr. L. Dippel considers that this fluid unites in itself all the properties required for such a fluid, and that it makes all others superfluous. Shurley’s Improved Slide for the Examination of Gaseous Matter.t—Dr. E. L. Shurley describes an apparatus for the examina- * Comptes Rendus, xciv. (1882) p. 1542. + Bot. Centralbl., x. (1882) pp. 224-5. t Proc. Amer. Soc. Micr., 4th Ann. Meeting, 1881, pp. 65-8 (1 fig-). Fic. 96. 552 SUMMARY OF CURRENT RESEARCHES RELATING TO tion of aerial or gaseous material, with the higher power of objectives, without subjecting it to any previous manipulations, thus enabling one to collect and immediately examine with any objective, “even a ss or perhaps a = inch.” The apparatus consists of a rubber bag (Fig. 97) with a tapering, hard rubber nozzle, into which is inserted a perfectly tight fitting stopcock. A piece of soft rubber tubing } inch in diameter and about 2 feet long is furnished at one end with a metal collar, to be inserted into the outer end of the brass canule of the slide; while the other is to be slipped over the nozzle of the bag. The larger extremity of a small canule about 13 inch long, is fixed by a binding screw into the upright B on the glass slide, while its small end is inserted into the minute hole at the side of the cell. The larger extremity is smoothly ground, to receive the metal-finished end of the conducting tube. The slide has an ordinary cell A (of rubber). The cell has its middle portion built up from the bottom by a piece of glass, so as to bring it within the working distance of the objective, allowing depth enough at the sides, which may be com- pared to two. ditches, for the introduction of a canule of reasonable Fic. 97. calibre. This, the author says, is an important point, inasmuch as a cell shallow enough for the adjustment of its bottom to the focus of a first-class 4-inch objective, could have a depth of only about a fortieth of an inch, and of course for higher powers less, altogether too shallow to allow of the introduction of a canule of practicable size. But, upon this plan, the cell may be built up ever so much, even for adjustment of a ;!,-inch objective, while yet at its sides will remain the same depth of ditches, or sulci, for the ingress of the gas. The cover-glass may be cemented on, or laid on loosely. In the former case the opposite side of the cell must be perforated to allow ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 553 the gas to escape, while in the latter case it escapes by itself lifting up from time to time the cover-glass. As all objects or particles contained in the air or gas must be at rest when examined with the higher power objectives, it will be necessary to coat either the bottom of the cell, the cover-glass, or both, with something to which the material will adhere as the gas passes through. One of the best methods is to coat both the bottom of the cell and under side of the cover-glass with a thin layer of glycerine—somewhat after Beale’s method of collecting aerial germs. This coating is easily accomplished by previously moistening the glass with alcohol. The rubber bag and connecting-tube may be cleansed by drawing alcohol into them, and after expelling this they may be easily dried, if desired, by drawing and expelling air for awhile. All the parts being in proper connection, by opening the stop- cock of the receiver, and gently pressing upon it, the cell may be supplied at will. As before stated, any gaseous material can be collected and kept any length of time from the access of air, and when desired, directly examined under the Microscope without any intermediate manipulation; ‘‘a great desideratum and one which cannot be attained so far as I have been able to learn, by any other slide or apparatus hitherto in use. Those most used are the ‘Stricker’ and ‘ Hunt’ gas slides, the Holman ‘life slide,’ and the animalcule cell or cage, none of which is applicable in examinations with the higher power objectives; and none of which, excepting one, is arranged so as to allow of the direct introduction in small quantity of gaseous material. The advisability, nay, the necessity, of more perfect means for the examination of aerial or gaseous matter, must have been felt by every one who has ever attempted any work in this direction : and it is obviously only by patient investigation with high- power objectives that we can hope to discover the nature and habitat of those infinitesimal organic poisons which are supposed to originate in some unknown way the so-called zymotic diseases.” Hardy’s Compressorium.*—Mr. J. D. Hardy’s object in con- structing the compressorium shown in Fig. 98, is to remedy, to some extent, the defects of existing compressors as regards the difficulty Fig. 98. of regulating the pressure with exactness, the imperfect parallelism, and a deficiency of freedom of action, which causes great risk of losing or damaging the object under observation. * Journ, Quek, Micr. Club, i. (1882) pp. 35-6 (2 figs.). 04 SUMMARY OF CURRENT RESEARCHES RELATING TO A is a brass plate, 3 inches by 14 inch, in the centre of which is a round hole. At one end is a bent spring B, of thin brass, to which is hinged a second brass plate C, also with a central round hole, and bevelled on the upper surface for high powers. This second plate will, when turned down, overlie the plate A, and the two apertures will correspond. At the other end of the plate A, a button D is mounted so as to turn freely, and to rock on a short stud pind. The outer extremity of this button is bored and tapped to receive a small thumb screw e. A similar thumb screw / is also fitted to the plate C, near its hinge joint. A thin cover-glass is cemented to the upper side of the plate A, so as to cover the central hole, and the under side of the plate C is similarly provided. The mode of using this compressor is as follows:—The plate C is first turned down into place, and the distance that it is desired the glasses should be apart roughly adjusted by means of the screw /. The plate C may then be turned back, and the object placed on the lower glass; the covering-plate is then again turned down and secured by turning the button D over it. By means of the two screws d and f, the pressure can now be regulated with the greatest nicety without any risk of damaging or losing the object under examination. The arrangement admits of the glasses being easily cleaned and readily replaced by new ones when broken. Bulloch’s Diatom Stage.*—Mr. W. H. Bulloch has made a supple- mentary stage for use in arranging diatoms. It fits into the substage ring, and a stem projects up through the hole in the main stage. Upon the stem there is an arrangement like a double nose-piece, which carries two glass slips. One of the slips is intended for the material from which the diatoms are to be selected; the other for the prepared slide upon which they are to be mounted. The two slips can be moved about independently upon their supports. The hair or bristle is mounted on the mechanical stage. The slide carrying the material is first focussed, the diatom picked up, and the supple- mentary stage turned until the clean slide is in focus, when the diatom is placed in position. Substage Fine-adjustment.—At the suggestion of Mr. HE. M. Nelson, Messrs. Powell and Lealand have recently applied a fine- adjustment to their substage specially for use with their achromatic condenser. Fig. 99 shows (half-size) the under side of the substage with the new fine-adjustment in which A is a milled head controlling a screw-spindle terminating in a steel cone B. On rotating A, B turns and with a very slow motion forces up (or releases, as the case may be) a pin C inserted in the base-plate E of the substage. This motion of C carries with it the condenser. At right angles to, and forming part of H, at the back, an inner sliding plate works against a spring at the upper end between bearings F' at each side, which are fixed upon the usual racked slide D of the substage; this inner * Amer. Mon. Mier. Journ., iii. (1882) p. 97. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 555 sliding plate is the essential addition to the usual racked slide in the application of the new fine-adjustment to the substage. The range of motion is about } inch — the difference in radius between the smaller and larger ends of the steel cone. eS Ore Mr. Nelson states that he has * yi found the fine-adjustment on the fx ; substage of service in difficult in- ilk | qo vestigations with the condenser | in the axis. By this means he can readily exhibit the transverse lines of A. pellucida without any diaphragm. Sidle’s Centering Substage. —We gave a figure of Messrs. Sidle’s “ Iris” diaphragm in Vol. IIT. (1880) p. 1053, and briefly alluded to the centering arrange- ment of the substage as “a short bar working with a loosely fitting slot, that can be clamped beneath,” which is characterized as a somewhat primitive contrivance. Messrs. Sidle now adopt in their “Acme No. 2 Binocular,” the method of centering shown in Fig. 100, the special feature of which is that the substage motions are controlled by Fre. 100 two milled heads (right and left) on mie ES the arm or bar-attachment at the back of the substage carrier, racking on the swinging tail-piece. By this system the usual outer substage-ring, with its projecting centering screws (so generally adopted in America), is done away with. The forward mo- tion is given by the left-hand milled head acting on rackwork ; the lateral motion by the right-hand milled head acting on a pointed screw against a U-shaped spring that presses the slide towards that side, the fixed end of the spring being attached to the main base- or angle-plate racking on the tail-piece. We have not yet seen this mechanism, but with good workmanship we should anticipate the plan to be practical—certainly much better than the former system of centering by the rough process of pushing, pulling, and clamping by hand, which did not suggest the possibility of accurate centering. Mounting for the ‘‘Woodward” Prism.*—Dr. J. Edwards Smith recommends the form of mounting the “ Woodward” prism shown in * «How to Work with the Microscope’ (Svo, Chicago, 1880) p. 171 e¢ seq. 556 SUMMARY OF CURRENT RESEARCHES RELATING TO Figs. 101 and 102 (where in Fig. 101 A is a vertical view, and in Fig. 102 B a sectional view, and C the prism three-fourths full size). He states that this accessory is easily placed in position in the well- hole of the “ Acme” stand, and that doubtless with slight modifica- tions this system of mounting the prism may be applicable to other Microscopes. Provision is made for centering in a lateral direction Fig. 101. Se 2B SSE: GLU by means of the milled head at A. The prism can also be revolved by the milled head shown below so as to use either face, the faces being cut at different angles. Regarding the angles of the prism- faces, he thinks 98°, 41°, and 41°, as suggested by Dr. Woodward, are good ; but that 93°, 47°, and 40°, which he has himself adopted, are especially adapted for the general run of modern wide-apertured objectives. He gives detailed instructions for the use of the apparatus and thinks that it “bids fair to come into general use.” Prisms versus the Hemispherical Lens as Illuminators.—In various catalogues issued by American opticians, references are also made to sundry forms of mounting for the “Woodward” prism. It appears to us that much ingenuity is being wasted in such efforts, for whatever may be the angles of the prism-faces, the hemispherical lens — must necessarily entirely supersede it, having in fact an infinite number of facets through which normal light may reach the common centre. There may of course be cases where a small beam of parallel rays ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 557 directly transmitted by the plane prism-face may be thought to produce the purest effect of oblique illumination; but in our ex- perience wherever oblique light is required for the resolution of strie, &c., the slight condensation of rays produced by the curved surface of the hemispherical lens is no detriment, but rather the contrary, whilst for facility of manipulation the lens is greatly to be preferred. Mounting the hemispherical lens on a plate to be put immediately beneath the slide is not to be commended, for every movement of the slide then carries the illuminator with it, and the direction of the light requires continual readjustment. No better plan of applying the lens has been suggested than that adopted by Tolles and Ross, in which it is mounted to slide or screw into the stage-aperture from beneath. This plan is applicable to nearly all the modern Micro- scopes having mechanical stages. For the Microscopes generally used on the Continent, without mechanical stage-movements, the hemispherical lens may be mounted, as suggested by Professor Abbe, in a disk of metal made to drop into the stage-opening from above so that the plane face is flush with the level of the stage. Radial Tail-pieces—Since the introduction of the Zentmayer swinging tail-piece or swinging substage in 1876, several opticians have carried out the same principle, but instead of the pivot motion of Zentmayer a disk is applied at right angles behind the stage in which a movable zone is fitted to carry the tail-piece. In all the Micro- scopes we have inspected in which this plan is adopted, we remark that the attachment of the tail-piece is so slight as seriously to inter- fere with the firmness of the substage. This is a great inconveni- ence in all manipulations of the substage ; the rackwork, centering- screws, diaphragms, mirror, or whatever may be attached to the tail- piece, cannot be touched whilst the eye is directed through the Microscope, without the flexure of the tail-piece causing the illumina- tion to move from the field of view. Of course this applies only to the use of high powers, but all such Microscopes are supposed to be made specially for high-power work. Electric Light in Microscopy.—Referring to his previous paper on this subject,* Dr. Van Heurck sends us the accompanying Fig. 103, showing the Regnier battery which he has adopted in place of the Tommasi; the sulphate of copper being placed in the small basket at the left-hand side of the cells. The Regnier accumulator is also shown in Fig. 104. Dr. Van Heurck adds that the Regnier battery can be placed in the laboratory of the microscopist, as it does not give off any vapours. It will remain charged for at least a month if sulphate of copper is added as required. Sixty-four Regnier elements (each = 1:07 volts), charging sixteen accumulators, lighted a great part of his house for six weeks. They can be used with only one accumulator, to act as a * See this Journal, ante, pp. 418-20. 558 MMARY OF CUR RENT RESEARCHES R ELATIN G TO Fic. 108. I Mas > Fes ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 559 regulator of the current. If expense is not an object four accumu- lators may be used (requiring sixteen elements), the accumulators thus serving both as regulators and reservoirs, and allowing several lamps to be used at a time. The particular Swan lamps he uses are the ‘‘24-candle” lamps. Still later Dr. Van Heurck says that he is experimenting with some new accumulators of M. de Kabath, which seem likely to give good results. Black Backgrounds.*— Mr. Tuffen West on principle very much dislikes to see objects mounted with an irremovable black back- ground. When it is desirable to view objects as opaque, there are so many other ways of doing this; e.g. the diaphragm, the dark-well, a piece of dead-black paper, cloth, or velvet placed behind the slide. The object can then still be viewed as a transparent object also. Otherwise it is the mounter saying to the observer, “ You shall see my slide as I will, and in no other way.” Micrometrical Measurement by means of Optical Images.t—A paper on this subject was published some time since by Professor Abbe in German, and we at once had it translated with a view to its insertion in this Journal. We must frankly confess, however, our inability to put the paper in proper form for publication here, and as Professor Abbe is much taxed in various ways we have not thought it right to ask him to undertake the matter. We therefore content ourselves with a translation of a German abstract of the article. + “Hi. Abbe has turned his attention to the study of the Microscope as used with a micrometer, and finds that the sources of error belong- ing to the present methods of measurement can be obviated by using ‘telescopic’ systems of lenses instead of the ordinary objective with a finite focal distance. Such a glass is made up of two separate lenses or systems, whose focal planes are turned towards each other and coincide. It has an unlimited focal length, and the focal points lie at an infinite distance; all objects are reproduced with an enlarge- ment which may be determined at will, but is constant; so that this magnification remains independent alike of the distance of the object, that of the image, and of the length of the tube.” Malassez’s Improved Compte-globules.—Professor L. Malassez in 1880 published § a detailed paper on corpuscle-counters in which the various devices of himself, Hayem and Nachet, Gowers and Zeiss were fully referred to with a statement of their respective advantages and disadvantages, and in which he described an improved apparatus suggested by himself. An epitome of the paper by Mrs. Ernest Hart with critical observations has also appeared in English,|| so that it is unnecessary to refer to it otherwise than briefly here. * Journ. Post. Micr. Soc., i. (1882) p. 94. + SB. Jenaisch. Gesell, f. Med. u. Naturw., 1879, p. xi. t Jahresber. (Virchow and Hirsch) for 1879, p. 27. § Arch. de Physiologie, 1880, p. 377. | Quart. Journ, Micr, Sci., xxi. (1881) pp. 132-45 (3 figs.). 560 SUMMARY OF CURRENT RESEARCHES RELATING TO The improved apparatus is shown in Fig. 105. It is made by M. Vérick, and consists of a thick brass slide, having in the centre an © © 2 @® © (9) *71@ @| 6 © S @o ~ ® 6 @|9 © OE Wons tome © 3 5s 0° 4% e 2 9 Cele. @2 © &.|.2 © ~ FOO aperture, into which is fixed a circular glass block about a centimetre in diameter, with its upper surface level with the top of the slide, and ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 561 surrounded by a groove about half the thickness of the slide in depth. Outside this groove are three pointed metal screws equidistant from each other, the elevation of which above the surface of the slide is exactly } mm. Im the centre of the glass block the squares are drawn in which the corpuscles are counted. The sides of these are sly mm., and they are arranged in groups of twenty, as shown in Fig. 106 (x 200). To facilitate lowering the cover-glass so as to be exactly horizontal, M. Malassez devised the frame (Fig. 105) to the underneath part of which the edges of the cover-glass are attached by a little water or saliva. The frame is supported on two arms attached to one flange of Fic. 107. a hinge, the other flange being secured to the slide by a clasping screw. The frame with the cover-glass is raised or lowered by the longer of the two arms, and the operation may be quickly performed. A small spring clip keeps the whole down so that there is no danger of the cover being raised or displaced. Fic. 108. The mixing of the blood is effected in the “ Mélangeur Potain,” shown in Fig. 107, and the whole apparatus, with triangular knife for making incisions, cover-glass, and a bottle of diluting liquid, packs into a small pocket-case 13°5 x 8x 2°5 em. (Fig. 108). Ser. 2.—Vot. II. 2p 562 SUMMARY OF CURRENT RESEARCHES RELATING TO AsBE, E.—The Relation of Aperture and Power in the Microscope. This Journal, ii. (1882) pp. 300-9. Engl. Mech., XX XY. (1882) pp. 374-5. “ Akakia.”—Microscopy—Wide-angle Objectives. Engl, Mech., XXXV. (1882) p. 283. ss Microscope Power. [Reply to “ Antares,” infra, as to the non-increase of aperture of some oil-immersion objectives over the figures shown with Abbe’s Aperto- meter when water is used as the immersion fluid. An oil-immersion, if of only 1:25 N.A., will show that aperture with water, as it is below the maximum 1°33. Substituting oil cannot increase the reading, as the maximum aperture of the lens has been already measured. | Engl. Mech., XXXYV. (1882) pp. 309-10. American Society of Microscopists. [Review of ‘ Proceedings’ of 4th Annual Meeting at Columbus, O.] Amer. Natural., XVI. (1882) pp. 343-6. [Circular of the President, Dr. G. E. Blackham, as to the Elmira Meeting in August 1882, and Letters from him and Dr. Up de Graff. Also circular as to proposed Quarterly Journal of Microscopy, &c.] The Microscope, II. (1882) pp. 47-8, 85-7, 94. “« Antares.” —Microscope Power. [Partial statement . . . of the details of magnifying power provided by an ordinary well-furnished instrument of full size.” ] Engl. Mech., XXXYV. (1882) pp. 261-2. ull The Apertometer—Lantern Objectives. [Reply approving of the explanation given in “ Akakia’s” letter, supra, and account of further experiments with objectives. Also remarks on the Apertometer and Aperture-measuring. A query to Mr. Shrubsole as to Lantern Objectives. ] Engl. Mech., XXXY. (1882) p. 429. Baur, W. M.—On Recent Improvements in Microscopy. [Deals with objectives, illuminating apparatus, stands, stages, swinging tail-pieces, this Journal, &c.] Southern Science Record, Il. (1882) pp. 75-80. BEALE’s (L. 8.) Microscope in Medicine. 4th ed. (Review, with extended remarks on the germ theory of disease. ] Amer, Natural., XVI. (1882) pp. 500-4. Bowman, F. H.—The Structure of the Cotton Fibre in its relation to Technical Applications. 2nd ed. [Contains description of Microscope and Micrometers, pp. 7-14, and note on the “ Limit of Microscopic Vision,” p. 157.] 8vo, Manchester, 1882, xvi. and 211 pp. (5 figs. and 12 pls.). Boys, C. V.—Measurement of Curvature and Refractive Index. Engl. Mech., XXXV. (1882) pp. 469-71, from ‘ Philosophical Magazine.’ Brappury, W.—The Achromatic Object-Glass. I-VI. [Deals with “the theoretical conditions that must be satisfied in the formation of an object-glass.’’] Engl. Mech., XX XV. (1882) pp. 297-8, 344, 371-2, 393, 418-9, 440-1. Brirrain, T.—The Beginnings of Microscopic Study. [Brief general history of the simple and compound Microscope and Leuwenhoeck’s observations. j Field Naturalist, I. (1882) pp. 7-8. Buttocu, W. H.—Iris Diaphragm for Use above an Objective. [Claims to have been the first to introduce it, and refers to his Catalogue of 1878. J. W. Sidle subsequently writes referring to Dr. Royston-Pigott’s previous description of such an apparatus. | Amer. Mon. Micr. Journ., III. (1882) pp. 99, 117-8. Butiocu’s (W. H.) Apparatus for Measuring the Magnifying Power of Oculars. [Post.] Amer. Mon. Micr, Journ., III. (1882) pp. 103-4 (1 fig.). The Microscope, Il, (1882) pp. 83-4. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 563 Butiocn’s (W. H.) Improvements in Microscopes. [Supra, p. 554.) Amer, Mon. Mier. Journ., III. (1882) p. 97. CHARDONNET, de —.—Sur la transparence actinique des verres d’optique. (On the Actinic Transparency of Optical Glass.) Comptes Rendus, XCIV. (1882) pp. 1468-70. Curvatier, A.—L’Etudiant Micrographe. Traité théorique et pratique du Microscope et des préparations. (The Microscopical Student. Theoretical and _ practical treatise on the Microscope and preparations.) 3rd ed. 8vo, Paris, 1882, xvi. and 591 pp. (179 figs., 7 plates, and portrait). Coz, A. C.—Studies in Microscopical Science. Vol. I. No. 1 (pp. 1-8).—Yellow Fibro-Cartilage—Long. Vert. Sec. Pinna of Ear of Cow, double-stained in logwood and eosin. Plate x 333. No. 2 (pp. 9-20).—Trans. Sec. Dicotyledonous Stem — Copper Beech (Fagus cuprea), stained carmine and iodine green. Plate x 25. No. 3 (pp. 21-8).—Human Bone—Trans. Sec. Compact Tissue of Shaft of a Long Bone (Clavicle). Plate x 50. : No. 4 (pp. 29-32).—Trans. Sec. Monocotyledonous Stem — Umbrella Plant (Cyperus alternifolius)—Closed Fibro-Vascular Bundle, stained carmine and iodine green. Plate x 400. No. 5 (pp. 33-40).—Human Skin — Vert. Sec. Sole of Foot, stained carmine and sulph-indigotate of soda. Plate x 65. No. 6 (pp. 41-8).—Section of Pikrite (Inchcolm, Firth of Forth). Plate x 25. No. 6a (pp. 49-64).—Same continued with Analytical Chart. No. 7 (pp. 65-74).—Trausverse Section of Spinal Cord of Cat—dorsal region. Plate x 20. No. 8 (pp. 75-78).—Transverse Section of underground portion of Rachis of Frond of Bracken Fern (Pteris aquilina). Plate x 333. No. 9 (pp. 79-86),—Vertical Section of Human Liver, stained logwood. Plate x 233°3. No. 10 (pp. 87-92).—Transverse Section of Thallus of Fucus vesiculosus with Antheridia and Oogonia. Plate x 154. No. 11 (pp. 93-102).—Vertical Section of Liver of Cat, injected (hepatic vein red, portal vein blue). Plate x 50. No. 12 (pp. 103-8).—Transverse Vertical Section of a Leaf (Rhododen:Jron ponticuin), stained logwood. Plate x 333. Reviewed in Journ. of Sci., [V. (1882) pp. 374-5. Sci.-Gossip, 1882, pp. 138, 160, and 186. Knowledge, I. (1882) p. 609. Nature, XX VI. (1882) p. 89. North. Microscopist, II. (1882) pp. 163 and 193. The Microscope, IL. (1882) p. 93. Cox, J. D.—Measurement of Microscopic Aperture. [Abstr. of article, ante, p. 422.] Amer, Natural., XVI. (1882) pp. 532-3. Crisp, F.—Notes sur l’Ouverture, la vision microscopique et la valeur des objectifs & immersion & grand angle. (Notes on Aperture, Microscopical Vision, and the value of wide-angled Immersion Objectives)—contd, . [Transl. of paper I. (1881) pp. 303-60. ] Journ. de Microgr., VI. (1882) pp. 246-51 (2 figs.), 299-303 (6 figs.). CrumepaucH, J. W.—The History of the Microscope and its Accessories, I. I. The Microscope, II. (1882) pp. 33-8, 65-9. Davis, G. E.—Practical Microscopy, 2nd ed. 8vo, London, 1882, viil. and 335 pp. (258 figs. and 1 pl.). Ist ed. reviewed in Amer. Natural., XVI. (1882) pp. 432-3. Nature, XXV. (1882) pp. 502-3. Sci.-Gossip, 1882, p. 112. 3 “ The Limiting Diaphragm or Aperture Shutter. [Comment on the statement, ante p. 407, that objectives of wide aperture cannot be made to do duty as narrow-angled ones also, so as to dispense with two classes of objectives. ] North, Microscopist, II. (1882) p. 194. 2Pe2 e 564 SUMMARY OF CURRENT RESEARCHES RELATING TO Desy, J., and F. Kirron.—A Bibliography of the Microscope and Micro- graphic Studies, being a catalogue of books and papers in the library of J. Deby. Part III. The Diatomacee. (Part 3 in advance of Parts 1 and 2.) 8yvo, London (privately printed) 1882, 67 pp. Dieret, L.—[Review of Dr. H. Van Heurck’s paper on homogeneous-immersion objectives and finids (cf. this Journal, ante, p. 264), preceded by a statement of his reasons for objecting, in opposition to Dr. Van Heurck, to correction-adjust- ments with such objectives. See also supra, p. 551. Bot. Centralbl., X. (1882) pp. 222-5. Epuunps, J.—See Wenham, infra. ENGELMANN, T. W.—Appareil Microspectral (Microspectroscopie Apparatus). [For experiments on the disengagement of oxygen by vegetable cells, post. ] Rev. Internat, Sci. Biol., TX. (1882) pp. 465-7. Fa.LkinpurcG, W. S.—Hints to Amateur Microscopists. [How to make a bull’s-eye condenser from an old-fashioned bull’s-eye watch-glass filled with glycerine and closed with plate glass. | Amer. Mon. Wicr. Journ., 111. (1882) p. 92. F.R.M.S. and “ Another F.R.M.S.”—See Wenhan, infra. Go.tzscu, H.—Binoculares Mikroskop (Binocular Microscope). [Post.] Zeitschr. f. Instrumentenk., Il. (1882) pp. 225-6 (1 fig.), from Carl’s Repertorium fiir Experimental-physik, xviii. (1882) pp. 27-32. GUILLEMARE, —.—See Lutz, EH. - GunpLacH, E.—Oblique Illumination, with a special consideration of the capabilities of Immersion Condensers, and a note on Symmetricai Illumination. [ Post. ] Amer. Mon. Micr. Journ., III. (1882) pp. 85-8 (1 fig.). Haut, L. B—An Eye-protector for use with the Monocular Microscope. [Post.] The Microscope, 11. (1882) pp. 88-90, from Vedical and Surgical Reports. Hevrcg, H. Van.—The Electric Light applied to Microscopical Research. (Transl. of paper, ante, p. 418.] North. Wicroscopist, 11. (1882) pp. 141-7 (1 fig.). See also Rev. Wycologique (1882) p. 199. Hick, —.— Microscopic Tank. {Inquiry how to make a small tank for microscopic use (10 x 8 x 2), opaque ends and bottom.] [Reply by J. A. Ollard—* crystallized dishes of about 7 inches diameter.” ] Sci.-Gossip, 1882, pp. 142 and 160. Hincenporr, F.—Apparat fiir mikroskopische geometrische Zeichnungen. (Apparatus for Microscopical Geometrical Drawings.) SB. Gesell. Nat. Fr. Berlin, 1882, pp. 58-60. Hitcncock, R.—Numerical Aperture. [« A plain statement of what numerical aperture is.”] Amer, Mon. Micr. Journ., IIl. (1882) pp. 95-6. si 5, The Microscope Trade. [Protest against underselling.] Amer. Mon, Mier. Journ., II. (1882) p. 97. x » Newspaper Science. [Quotations of “ conglomerations of error and deliberate falsehood” in an article in the Mechanical News on the ‘ Power of the Microscope.’] Amer, Mon. Micr. Journ., TIL. (1882) p. 98. J., T. R.—What is the meaning of the sign x? [Reply to E. Holmes, ante, p. 423, and insisting upon the correctness of his former view. ‘‘The idea of amplification alone does not cover the meaning of the sign x as used microscopically . . . . not algebrai- cally or mechanically.”} Sci.-Gossip, 1882, p. 159. Kirron, F.—See Deby, J. we ee ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 565 Lancaster, W. J.—See Sturt, T. J. LANDsBERG, C.—Ueber den Antheil der Proving Hannover an der Entwick- lung der Feinmechanik. (On the Share of the Province of Hanover in the Development of Fine Mechanical Work.) [The pages noted contain a correction of Harting’s statement in ‘ Das Mikroskop,’ that S. G. Hoffmann (who made Microscopes in the second half of the 18th century) was a Hanoverian—he in fact lived in Leipzig. 2 ek eR f. Optik u. Mech., III. (1882) pp. 159-60 (foot-note). Lossner, O. M.—Telemikroskop (Telemicroscope). [Abstract of Patent—see ante, p. 424 and supra, p. 547.] Centr.-Ztg. f. Opt. u. Mech., III. (1882) p. 108. Lovett, E.—Dark-ground Illumination. {Incorrect heading—relates to white or porcelain backgrounds and slips of glass to be put under the slide, either of pale blue (for modifying the light), opal porcelain or china (for viewing dark objects as opaque, such as seeds), dull varnished on one side (for most opaque objects), or ground glass (for Foraminifera). | Journ. Post, Micr. Soc., I. (1882) pp. 94-5. Lutz, E.—Microscope scolaire (School Microscope). [Designed by Professor Guillemare, post. ] Journ, de Microgr., VI. (1882) pp. 233-5 (1 fig.). See also Rev. Mycologique, IV. (1882) p. 199. M‘A.uister’s (T. H.) Protector for Objectives. [Copy of the Richards’ Protector. ] Amer. Natural., XVI. (1882) p. 618 (2 figs.). Merz, 8.—Ueber Dispersions-Verhaltnisse optischer Glaser. (On the Dis- persion Relations of Optical Glass.) [Discussion of the best combinations of flint and crown glass to remove the secondary spectrum. } Zeitschr. f. Instrumentenk., 11. (1882) pp. 176-80. Microscope by Culpepper and Scarlet, formerly in the possession of Sir A. Lever, exhibited and briefly described at meeting of Manchester Microscopical Society. North, Microscopist, IL. (1882) p. 189, Moorsz, A. Y.—Something about Objectives. [Post.] The Microscope, II. (1882) pp. 8-11. Moss, J. M.—See Wenham, infra. Mounting Micro. Lens. [Directioas by W. J. Lancaster. See also ante, p. 424.] Engl. Mech., XX XV. (1882) p. 335. Mcnro, J. M. H.—Battery power for Swan Lamps. [40 Grove cells were found to be necessary for 3 Swan lamps of 25 to 50 candle power—8 to 10 cells will probably be sufficient for lamps of 5 candle power. ] North. Microscopist, II. (1882) pp. 150-1, from The Vechanical World. Netson, E. M.—See Wenham, infra. es a Tuberculosis. [Contains reference to a 3.-inch oil-immersion objective 1:38 N.A. “ speci- ally constructed for me by Powell and Lealand for the purpose of investigating micro-organisms, and may fairly rank as the greatest achievement in the science of microscopical optics ”—also to a fine adjustment to the substage of the Microscope which * will be found most bck by those engaged in observations with wide-angled high powers.” Engl, Mech., XXXYV. (1882) p. 378 (2 figs.). OxuarD, J. A.—See Hickin. i » Tadpole Slides. [Description of Schultze’s, ante, p. 110, and of the following. “Forma groove or cell on an ordinary slip of glass with folded blotting-paper 566 SUMMARY OF CURRENT RESEARCHES RELATING TO saturated with water; lay the tadpole in between on the glass, tail flat ; cover the body over with saturated blotting-paper, the tail Gf necessary) with thin glass. Keep the whole well saturated, and the tadpole will live for many exhibitions.’”] Engl. Mech., XX XY. (1882) p. 284 (1 fig.). Ouuarp, J. AA—The Microscopist’s Companion. [Description of a support for pocket lens with forceps and Forrest’s Compressorium. | Engl. Mech., XXXYV. (1882) p. 330 (2 figs.). PELLETAN, J.—[Announcement of an intended publication of papers on (1) The theory of the Microscope ; (2) The theory, construction, and use of Objectives ; (8) Microscopes. ] Journ, de Microgr., VI. (1882) p. 206. See also Rev. Mycologique, IV. (1882) p. 198. Postal Microscopical Society’s Journal. [Notice of Nos. 1 and 2.] Amer, Natural., XVI. (1882) p. 533. Sci.-Gossip, 1882, p. 186. President’s Address. [Abstract in part and note, ‘‘ As a whole it is one of the best, most clear, sensible, and intelligible presidential addresses that it has been our good fortune to read for some time.’’] Amer. Mon, Micr. Journ., III. (1882) pp. 106-11, 116. Proctor, R. A.—The Eyes of Science. [Deals principally with the extension of the power of human vision by * photographie processes and methods—brief reference to the Telescope, Microscope, Spectroscope, &e.] Knowledge, II. (1882) pp. 54-5. Reppinc, T. B.—The Microscope : its revelations, with some of their bearings upon Christian Evidences. Acton Lectures. 8vo, Indianapolis, 1881, pp. 129-48. Reynier, E.—An Electric Battery for the Laboratory and Dvwelling- house. [Translation from La Nature, describing the battery mentioned ante, p. 418-9. ] : North. Microscopist, 11. (1882) pp. 147-50. RovumEGtERE, C.—Le Microscope populaire en Amérique. (Popular Microscopy in America.) [Note as to the rapid progress made in the New World by micrography, with special reference to the Michigan University and Ann Arbor Soirées. | $ Rev. Mycologique, IV. (1882) pp. 199-200, SrrBert, W.—Anwendung des Tépler’schen Schlieren-Apparates auf Mikro- skope. (Use of the Tépler Apparatus in Microscopy.) [ Post. ] Zeitsohr. f. Instrumentenk., 11. 1882) pp. 92-6 (3 figs.), Abstr. in Centr.-Zig. f. Opt. u. Mech., TIL. (1882) p. 105 (2 figs.). Sipiz, J. W.—See Bulloch, W. H. Srpix’s Iris Diaphragms and “ Acme” Stands. [Brief description. ] North. Microscopist, II. (1882) pp. 190-1. SrEINHEIL’s Eye-pieces. See this Journal, supra, p. 551. Engl. Mech.. XX XV. (1882) p. 458. Sroxzs, A. W.—A Tadpole Slide. [Objections to the plan of ‘‘ Volvox ” (ante, p, 438), as it prevents the use of a higher power than the 4 in.; it never ensures the tail lying flat from end to end, and the use of chloroform retards tle circulation. Description of his own Tadpole Slide (ante, p. 110).] Engl. Mech.. XX XV. (1882) pp. 237-8 (1 fig.). (ts Se a ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 567 StoweEtt, C. H. & L. R.—Editorial Notes. [As to the first vol. of ‘ The Microscope "—Bausch and Lomb’s “ 3 homo- geneous,” homogeneous-immersion condenser, mechanical finger and turntable, &e.—Arnold’s Photomicrographs—Teichmann’s Hemin Crystals—Prof. A. Y. Moore’s Resolution of “ Amphipleura pellucida with a 2 homogeneous by Central Sunlight” — Ward’s Pigeon-post Films—&e.] The Microscope, II. (1882) pp. 18-20. [Elmira Meeting of the American Society of Microscopists—&c. ] The Microscope, II. (1882) pp. 50-4, Stvurt, T. J.—Microscopic. [As to using a bi-concave spectacle lens fitted to the draw-tube for table purposes, so that “‘a 2 in. can be used to magnify to the same extent as a 3 in.”—also further query by “ Handy-Man,” and reply by W. J. Lancaster. ] Eng!. Mech., XX XV. (1882) pp. 282-3, 339, 385. Tuoms, W. A., Election of. Amer, Natural., XVI. (1882) p. 621. Wate, G.—See Wenhan, infra. Weap, C. K.—Studies with Micrometers. [(1) Results of comparisons of Rogers’ Micrometers and Fasoldt’s test- plates. (2) On the effect of the cover-correction in changing the magnifying power. (3) Measuring the thickness of cover-glasses by the correction-collar, post. The Microscope, II. (1882) pp. 69-73. Wenuan’s New Microscope. [Further letters by F. H. Wenham, (2) J. M. Moss, Dr. J. Edmunds, and * Another F.R.MS.,” “F.R.MS.,” G. Wale, aud E. M. Nelson, as to the priority of design.] Engl. Mech., XX XV. (1882) pp. 282, 309, 330, 356, 356-7. Wicanb, O.—Verbessertes Skioptikon (Improved Sciopticon). [Post.] Centr.-Zig. f. Opt. u. Mech., III. (1882) pp. 101-2 (1 fig.). Wooster, W. H.—On an Impromptu Bramhall Reflector. (The mirror removed from the Microscope and placed on the stage with the slide on it, condensing the light with the condenser. ] Journ, Micr, Soc. Victoria, I. (1882) pp. 100-1, Zencer, C. V.—Sur une nouvelle combinaison des lentilles du Microscope. (Qn a New Combination of Microscope Lenses.) [Supra, p. 551.] Comptes Rendus, XCIY. (1882) p. 1542, 8. Collecting, Mounting and Examining Objects, &c. Cutting and Mounting Microscopical Sections.*—Mr. A. G. Bourne describes some modifications of older processes, which he considers constitute the latest stage of development of the section- cutter’s art. Hardening.— Any of the ordinary hardening methods may be used, but it is essential that all trace of acid should be removed in order to obtain good staining results. Corrosive sublimate is an exceedingly useful hardening reagent, and tissue treated with it stains as readily as if treated with alcohol only. The solution used is a concentrated one. The fresh tissue or living animal is placed in it for fifteen to thirty minutes, according to its size; it is then washed in water and transferred to alcohol of 50 per cent.—a large relative bulk of this must be used, and the tissue well permeated by it, otherwise some * Quart. Journ. Micr. Sci., xxii. (1882) pp. 334-7, 568 SUMMARY OF CURRENT RESEARCHES RELATING TO corrosive sublimate is left in the tissue and is thrown down in needles when strong alcohol is added. After 24 hours the tissue is trans- ferred to alcohol of 70 per cent., and after 24 hours to alcohol of 90 per cent., and then to absolute alcohol. With large pieces of dense tissue this should be changed once or twice. After two or three days the tissue is ready for staining, If time is an object, and no acid has been used in the hardening, the tissue may be transferred directly from alcohol of 70 per cent. to the staining fluid; but it is advisable, and in the case of delicate tissues necessary, to complete the hardening process before staining. Staining.—Grenacher’s alcoholic borax carmine is used. Pure carmine (2°5 per cent.) is added to the solution of borax (4 per cent.), in water ; this is allowed to stand for two or three days, and occasion- ally stirred—the greater part of the carmine will dissolve. To this solution is added an equal bulk of alcohol of 70 per cent. This mixture must stand for a week and then be filtered, when it is ready for use. If on keeping more carmine is deposited, it should be refiltered. The tissue is placed in this solution, and allowed to remain one, two, or three days according to its size; it is hardly possible to over- stain, and there is sufficient alcohol in the solution to prevent injury to any but the most delicate tissues. For such tissues a solution can be prepared containing more alcohol, but of course less carmine. The tissue when removed from the staining fluid is placed in alcohol of 70 per cent., acidulated with hydrochlorie aeid (8 to 6 drops of the acid to 100 cc. of spirit). This dissolves out all excess of carmine and fixes the rest. The tissue, 2 dark purplish-red when taken out of the borax carmine, should be left in the acidulated alcohol till it aequires a bright transparent look (3 to 6 hours), it may then be transferred to absolute alcohol and afterwards to tur- pentine. When thoroughly permeated with this latter (the time necessary varying as the size of the lump of tissue) it is ready for imbedding. Imbedding.—This is: done in paraffin, and it is exceedingly im- portant to obtain a suitable paraffin. It shouid melt at 100° or 115° F. Paraffin of various melting points should be kept in the laboratory ; they may be purchased at the dealers. The tendency to curl up on the part of the section may be reduced to a minimum by obtaining a paraffin of the proper consistency, but this seems to vary according to the temperature of the room in which the sections are cut. The paraffin must be melted in a small covered vessel in a water- oven, great care being taken to keep it in a dry atmosphere. The temperature in the oven should never rise more than two or three degrees above the melting point of the paraffin used. When the paraffin is melted the tissue is removed from the tur- pentine and placed in it, and this must be kept at its melting point for some hours until the tissue is thoroughly permeated ; it may then be poured into a paper trough, watch-glass, or any other vessel, and allowed to cool. = ae ZOOLOGY AND BOTANY, MICROSCOPY, ETC. _ 569 Cutting.—There are two forms of microtome suitable for cutting sections in series. In one the tissue is raised directly by a fine screw, and the sections cut with an ordinary razor: in the other form, now so largely used, the tissue in its holder is moved up an inclined plane, and the sections cut with a large knife which works backwards and forwards in a horizontal slot running parallel with the inclined . plane. In both cases the machine is fixed to the table or heavy enough to remain steady, so that while the razor is worked with one hand the other hand is at liberty to hold a little paper spatula—a small piece of paper run on at the end of a small scalpel—to prevent the sections curling. The paraffin block is pared down to the smallest size possible, and, as the razor is drawn along, the edge, which com- mences to curl, is caught by the paper and prevented from so doing; the section is then transferred to the slide. Preparation of the Slide.—The slide is smeared with a strong solution of shellac in anhydrous creosote. Care must be taken to have as little as possible on the slide. By this method the sections are stuck to the slide, thereby saving the most delicate objects from falling to pieces after the paraffin is removed, and enabling one to mount numerous sections on one slide. The importance and value of this treatment cannot be over-estimated. It enables one to mount with absolute certainty whole sections of the most friable objects, such as an insect, without a single fragment of the section becoming displaced. Mounting.—The slide bearing the sections is now placed in a water-oven or on a tin box containing water at a temperature two or three degrees above the melting point of the paraffin used. The slide is left here for at least half an hour. The object of this warming is twofold, to evaporate the creosote and to melt the paraffin. The slide is now taken up, and while the paraffin is still molten is flooded with turpentine dropped from a small pipette. This dis- solves melted paraffin instantaneously, and precipitates the shellac fastening the sections to the slide. The turpentine is allowed to flow off, and replaced by new until all the paraffin is removed. The slide is then allowed to drain, the edges wiped, and the cover-glass put on. The Canada balsam, which should be very fluid, is placed on the under surface of the cover-glass; this is turned over and quickly lowered. The balsam dissolves the shellac, and if the cover-glass is not put on very quickly the sections may shift or delicate sections come to pieces and float off the slide. It being necessary to use the balsam in such a fluid condition, and a certain amount of turpentine always remaining upon the slide, the slides should be looked over the next day and more balsam added at the edge of the cover-glass if necessary. ‘These methods, especially that of fastening the sections to the slide with shellac, although suggested and elaborated by zoo- logists for the purpose of mounting serial preparations, will, no doubt, come into very general use in ordinary histology for such tissues as placenta or spleen where very thin sections have always been found liable to fall to pieces, and the most important pieces to fall out and be lost. 570 SUMMARY OF CURRENT RESEARCHES RELATING TO Preparing Blastoderm of the Chick —C. Koller,* who has taken up this subject in order to decide some disputed points in the embry- ology of the chick, thus describes the method by which his prepara- tions were made. The egg was subjected to the hatching method recommended by Kélliker. At the proper time it was opened and its contents carefully transferred to a glass; as much of the albumen as pos- sible being removed by the fingers or otherwise. In order to keep a note of the exact direction in which it was wished to take the sections, it was generally found necessary to make an indication on the egg while still fresh, as in the earlier stages the appearances in the surface of the yolk are rendered indistinct by the process of hardening; to this end, Koller has been accustomed to insert with forceps a small triangular pointed slip of paper into the yolk im- mediately behind the germinal disk in such a way that it indicates the extreme posterior margin of the blastoderm, and lies at the same time in the median plane of the future embryo. The yolk is now submitted for twenty-four hours to the action of a +, per cent. solu- tion of chromic acid, and then for another twenty-four hours to one of 1 per cent., and thus increasing the strength daily up to 4 per cent. If the yolk is sufficiently hardened, the segment on which the blasto- derm lies, together with the central mass, is detached with a fine scalpel and immersed in distilled water for twenty-four hours to remove the superfluous chromic acid. The yolk-membrane may he very readily removed from the hardened germ without injuring the latter. The blastoderm is stained entire with weak ammoniacal carmine (length of staining twelve to twenty-four hours), then washed by twenty-four hours’ immersion in distilled water and placed in absolute alcohol. It is ready for cutting in from one to two days. After lying for a few minutes in oil of cloves it is imbedded in a mixture of wax and oil. Sections are made by hand, using turpentine to moisten the object. Preparing Embryos of Insects.t—In a paper on the embryonic development of the Bombycide, Dr. §. Selvatico describes the methods he has made use of both for the preparation of entire embryos and for sections. The species employed were Bombyx mori, Atiacus Mylitta, and Saturnia py7t. The eggs are first coagulated by plunging them in water at 75° C. With a pair of fine-pointed forceps a small piece is removed from the shell, in the case of Bombyx, without disturbing the underlying parts. With a little care this is easily done, because on the eggs becoming cold their contents are somewhat contracted and do not teuch the shell. In the case of Attacus and Saturnia the eggs have a harder shell but are larger, and a razor was employed by the author. They are then hardened by leaving them for twelve hours in a -002 per cent. solution of chromic acid, and for twelve hours more in a ‘005 solution. Then with a little care the shell can be easily * Arch. Miky. Anat., xx. (1881) pp. 181-2. + Journ, de Microgr., vi. (1882) pp. 220-1, ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 571 removed by employing the forceps or cutting it round with a razor. The entire contents having been removed the egg is freed from chromic acid by leaving it in 30 per cent. alcohol for a day, the alcohol being renewed until it is no longer coloured yellow. For staining, the egg is placed in picrocarmine for twenty-four hours and washed in 30 per cent. alcohol to remove the picric acid. When it has been well washed it may be kept in 30 per cent. alcohol until sections are required. Previous to cutting sections the egg should be placed in absolute alcohol for half an hour, and then for a few moments in essence of bergamot. Dry and imbed in a mixture of 4 parts of spermaceti and 1 of cacao butter, to which is added, according to the temperature, some drops of castor-oil. The knife should be moistened with olive- oil and each section washed with a mixture of 4 parts of oil of turpen- tine and 1 of creosote to dissolve the imbedding substance surround- ing the section. Mount in Canada balsam. To preserve the embryo entire, the shell is to be removed as above described, after coagulation. The egg is then placed in a drop of water on the stage, and with a low power the embryo is extracted from the vitellus. It is cleaned as much as possible, so that no portion of the vitellus adheres to it, and mounted in glycerinated gelatine, previously coloured with methyl-green. By this method the embryo takes from the gelatine an excess of colour, and is thus stained after the preparation is made. If it is coloured first and then placed in colourless gelatine it will always lose colour (sometimes completely) if the gelatine is only a little greater in volume than the embryo. Collecting, Staining, and Fhotographing Bacteria.*—Dr. G. M. Sternberg in “a contribution to the study of the bacterial organisms commonly found upon exposed mucous surfaces and in the alimentary canal of healthy individuals ” (which contains much interesting matter), states that he has found the following to be the most satisfactory method of collecting bacteria for examination with high powers and for photography. The slightest possible smear of the material to be examined is allowed to dry upon a thin glass cover, and to secure a sufficiently uniform layer, it is usually best to spread it while moist with the end of a glass slide. Material is obtained from the mouth by scrap- ing the surface of the tongue, or of the teeth, with a clean instrument ; from the female vagina by a speculum or: digital examination; and from the male urethra, by applying a thin glass cover directly to the moist mucous membrane at the extremity of the canal. A five-cent bottle of aniline violet ink furnishes an ample supply of staining fluid of the best quality. Two or three drops of this - placed upon the thin cover will very quickly—one to three minutes— give the tacterial organisms attached to its surface a deep violet colour. The cover is then to be washed by a gentle stream of pure water, and is ready for immediate examination, or may be mounted * Stud. from the Biol. Lab. Johns Hopkins Univ., ii. (1882) pp. 157-81 (19 photomicrographs). 572 SUMMARY OF CURRENT RESEARCHES RELATING TO for permanent preservation over a shallow cell containing a solution of potassium acetate (Koch’s method), carbolic acid water (2-5 per cent.), camphor water, or simply distilled water. To make satisfactory photographs of the smallest bacteria, it is necessary to use a staining fluid which will give a stronger photo- graphic contrast, as the violet is transparent for the actinic rays. For this purpose aniline brown (recommended by Koch) may be em- ployed, or iodine solution (iodine 2-5 grains, potassium iodide q. s. to dissolve, distilled water 100 grains). A recent writer (Soubbotine *) advises the use of osmic acid as a fixing solution to be used in advance of staining. This is doubtless desirable when specimens of blood or thin sections of tissue containing bacteria are to be examined, as the normal histological elements are better shown, but the method possesses no special advantages so far as the demonstration of vegetable organisms is concerned. It must be remembered that aniline solutions often contain a granular precipitate which might be mistaken by a novice for deeply stained micrococci. Ehrlich’s Method of Exhibiting the Bacteria of Tuberculosis,t— Dr. Ehrlich, Prof. Koch’s assistant, has lately explained { a new method of preparing tuberculous bacteria, which is a great improve- ment on the original process of Koch. It renders the demonstration much easier, and its results are so certain, that it may be applied to establish the diagnosis of the disease in doubtful cases. The pre- parations made according to the method recommended by Koch in his first paper (i.e. double staining by alkaline methylene-blue and vesuvin §) have left doubts in the minds of some observers, which they could not have had if they had seen the preparations obtained by Ehrlich’s process which Koch himself has now adopted in prefer- ence to any other. Tuberculous bacteria as well as all the micro-organisms, bacteria, or micrococci, have a great affinity for aniline colours, and are strongly stained by them. Koch’s researches have shown that the bacteria of tuberculosis have special and characteristic properties, and that their cellular membrane is very easily penetrated by alkalies. It is upon this experimental fact that Koch based his ingenious method, which consists essentially in impregnation by an aniline colour, rendered alkaline by the addition of a small quantity of caustic potash. But this alkali exercises a modifying action on the different histological elements and on the bacteria themselves. Under its influence the albuminoid corpuscles swell to excess, and the coagulated layers of morbid matter are easily detached from the cover-glasses. Ehrlich, therefore, sought for another base, acting in a less powerful manner, and found it in phenylamine or aniline. Other alkaloids, perhaps even vegetable alkaloids, which can be transformed into colouring matters by means of various reagents, might be equally useful. * Arch. de Phys., viii. p. 479. + Bull. Soc. Belg. Micr., vii. (1882) pp. exvii—cxxii. { See Berl. Klin. Wochenschrift, 6th May, 1882. § Cf. this Journal, ante, pp. 385-8. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 573 The following is Dr. Ehrlich’s method of procedure, which does not present any technical difficulty, and does not require more than an hour to make a dozen preparations. By means of a dissecting needle a particle of expectorated matter, about the size of a pin’s head, is taken up and spread between two cover-glasses, * in two exceedingly thin layers on each. The cover-glasses are then separated by sliding one on the other, and left to dry protected from the dust. After a few minutes they are dry, and the fixing of the albuminoids and mucin is proceeded with. For this they can be warmed for an hour at 100° or 120° C., or which is simpler, rapidly passed four or five times through the flame of a spirit-lamp. To colour the prepara- tions a saturated solution of phenylamine is to be made in distilled water, by shaking with the water the excess of aniline which floats on it, and carefully filtering the whole. To the transparent liquid thus obtained add, drop by drop, a saturated alcoholic solution of fuchsine or methyl-violet until a slight opalescence is produced. The preparation should not be immersed in the colouring bath, but be placed in such a manner as to float on it, and to have the surface which is covered with the tuberculous matter in contact with the liquid. After a quarter to half an hour the staining is complete. If examined in this condition it is seen that the preparation is of such an intense colour that it is impossible to distinguish its elements, and Ehrlich happily thought of trying to decolorize it by means of a strong acid ; colourless salts of aniline are then formed, which are very soluble in water and disappear by washing with distilled water. The bacteria, not being penetrated by the acids, preserve their colour. In order to secure that they alone shall be coloured, therefore, it is only necessary to immerse the cover-glasses in nitric acid diluted with twice its volume of water. Nitrous vapours are at once disengaged, and the preparation becomes absolutely colourless in a few seconds. Under the Microscope the bacteria are seen to be very clearly coloured red or violet; but by reason of their extreme delicacy they often escape the eye and require the most accurate focussing. It is therefore better to study them in prepara- tions which have been slightly coloured blue or green (when fuchsine has been used for the first bath), or yellow (when methyl-violet has been used). They are afterwards mounted in Canada balsam in the usual way. The advantages of Ehrlich’s method are summed up by Dr. E. Van Ermengem as follows :—I1st. The aniline alters the form of the histological elements much less than Koch’s solution of potash. 2nd. The process is much quicker, and does not occupy more than an hour. 3rd. Its principal advantage is to produce a more intense staining of the bacteria, so that they appear larger, and can be recognized with a lower power, even with 250 diameters. ‘A question of the highest interest from a medical point of view * Ehrlich chooses cover-glasses whose thickness is appropriate to the objectives to be employed; those from 0°10 to 0°12 mm. he considers the most suitable. + The water dissolves about one part in thirty-one at the ordinary tempera- ture, 12° C, 574 SUMMARY OF CURRENT RESEARCHES RELATING TO has been raised by Ehrlich with reference to his method. The pro- perties which the membranous envelope of the bacteria of tuberculosis seems to possess, prove that the sole disinfectants or antiseptics which can be used to combat this disease, by acting on the bacteria, should be alkalies and not acids, which have hitherto been employed for this purpose. At the May meeting of the “Société Belge de Microscopie,” Dr. Van Ermengem exhibited a series of preparations of tuberculous bacteria obtained from expectorated matter from five patients suffering” from pulmonary phthisis of the second and third degree. In each of these cases a few particles of the sputa sufficed to give at least one preparation in which the characteristic bacilli were found. The first series of preparations were made according to Koch’s method. The bacteria were few and difficult to find. They were feebly coloured (a pale blue), and were very small. ‘To show them clearly a very bright light, obtained by means of an immersion con- denser, and the use of a good immersion objective were necessary (1080 diameters). The second series were partly made by Ehrlich’s process. The bacteria were coloured a bright red by fuchsine, the rest of the pre- paration being completely colourless. In one of the preparations the typical bacteria were very numerous, in groups numbering from four to eight within large cells, or disseminated in pairs here and there, and it was not difficult to recognize the spores: often also they were placed end to end in pairs. The organisms corresponded well with the description given by Koch, and were perfectly recognizable without a condenser and without a high power (750 to 800 diameters.) A few good preparations were also shown in which the ground had been coloured blue. The bacteria were more easily found than in the others, and stood out clearly by their fine red colour from the rest of the preparation (450 diameters). — Specimens of these bacteria prepared by Koch (on his old method) were exhibited by Mr. Watson Cheyne and Mr. E. M. Nelson at the two soirées of the Royal Society on the 10th May and 21st June, and also at that of the College of Physicians, and attracted consider- able attention, not only from the interest which attached to Koch's discovery, but also for the excellent way in which they were shown. Preserving Infusoria and Amcebe.*—E. Korschelt refers to the method described by M. Certes for colouring and preserving Infu- soria,t in regard to which O. Biitschli in his abstract of the paper expressed a hope that it would be possible to find a more suitable pre- serving method as he could not place reliance on preservation in glycerine. The author considers that the following method (which he devised without knowing that of M. Certes) will enable prepara- tions to be made which leave nothing to be desired in regard to durability. The water in which the Infusoria are placed upon the slide must * Zool. Anzeig., v. (1882) pp. 217-9. + See this Journal, ii. (1879) p. 331. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 575 be as small in quantity as possible in order to prevent the animals swimming away during the process, which is entirely carried on under the cover-glass. After the cover-glass has been put ona drop of a 1 per cent. solution of osmic acid is added and sucked through from the other side, then water, 70 per cent. and 90 per cent. alcohol, and finally water again. For the colouring of the now sufficiently hardened and fixed animals, Weigert’s picrocarmine process* is recommended. This should act an hour and a half to two hours, the preparation being placed in a moist chamber in order to prevent drying. After removal of the colour 70 per cent., 90 per cent., and absolute alcohol, oil of cloves, and finally Canada balsam are added. This process, which in reality takes only a short time, gives very excellent results for many Infusoria. In the case of others, however, the use of osmic acid is not so good, and with Amebe it is entirely without result. For these organisms, therefore, a 2 per cent. solution of chromic acid is preferable, which must act for two to three minutes in order to harden them sufficiently, otherwise in washing they readily swell up and burst. The remaining process is the same as the previous one. The duration of the action of the agents varies of course for different animals, depending upon their size and fineness—the most different Infusoria and Flagellata have been preserved in this way without manifesting the slightest shrinking. The cilia and vacuoles are quite life-like, and show the nucleus and nucleoli with an intense red colour. By far the best result, however, of the method is, the author considers, in its use for Amabe, the preserving of which had hitherto not succeeded. They are fixed in the position in which they are at the moment of the chromic acid being added. Even in the fine pseudopodia the vacuoles are easily to be recognized. The nuclei are also distinctly coloured. In a postscript the author adds that Dr. A. Gruber, of the Frei- burg Zoological Institute, who had previously found the process very useful for Rhizopoda and allied organisms, has since tried it on Heliozoa and found it to succeed excellently. Preserving Protozoa.t—Referring to the preceding paper, B. Landsberg considers that it is a disadvantage that all the operations have to be performed under the cover-glass. It is scarcely possible, therefore, to prepare clean slides, as foreign bodies once under the cover-glass cannot be removed. It is also to be doubted whether the osmic acid can act with the necessary suddenness and in sufficient concentration, and finally there is the danger of the object swimming away. He therefore proposes a method which obviates all these incon- veniences, and which even a beginner can soon learn. A small quantity of water being placed in a watch-glass or on a slide (without a cover-glass), is observed under the Microscope, and when an object is seen which it is desired to mount it is sucked up by a fine pointed capillary tube, taking care to have a little * Arch. f. path. Anat. u. Physiol. (Virchow) Ixxxiv. t Zool. Anzeig., v. (1882) pp. 336-7. 576 SUMMARY OF CURRENT RESEARCHES RELATING TO water in the tube at first, so that the animal may not be destroyed by too strong a rush of water. The water is then emptied out of the tube into a drop of 1 per cent. osmic acid on another slide, and the acid allowed to act for about ten minutesasa maximum. The animal is then stained with Beale’s carmine, washed with water, and after gradually hardening in alcohol transferred to oil of cloves. Another process is to be recommended for small quick-swimming Protozoa. After it has been ascertained that the water in the watch- glass contains many Protozoa a sufficient quantity of osmic acid is poured in, and the subsequent processes of staining, washing, and transferring to alcohol and oil of cloves are all performed in the watch-glass. The animals are so fixed in the sediment that it is rarely any are lost in sucking off the fluid. Then a drop of the oil of cloves is taken up under the Microscope in a wider tube, and the organisms brought away isolated by the capillary tube and put at once into Canada balsam. Although Canada balsam preparations have the advantage of greater durability, yet glycerine is to be preferred for many Protozoa. In particular, Actinospheriuwm Hichhornit is much more beautiful in glycerine than in Canada balsam. The frothy condition of the ecto- sare is shown most clearly, and the contractile vacuoles remain, as in the living state, prominent at the surface of the animal. Staining the Nucleus of Living Infusoria.—We are sorry that by the interpolation of the word “erroneously ” at p. 281 it was made to appear that M. A. Certes was not justified in claiming as a “ new fact” the staining of the nucleus of living Infusoria. The author of the interpolation, to whom we have referred on the subject, informs us that the fact of the note dealing with the living animals had momentarily escaped his attention. Double Staining with Carmine and Anilin Green.*—Mr. T. W. Taylor obtains very beautiful results from the following method of using preparations of carmine and anilin green { together. The section is immersed from five to ten minutes in the green, and then passed at once into the carmine, in which it remains from one to three minutes, the process being carefully watched in order that the carmine may not stain too deeply. It is then thoroughly washed in absolute alcohol, passed through oil of cloves, and then mounted in solution of balsam in benzole. The use of the benzole- balsam is important, as it has a decided action in fixing the stain, due to the presence of benzole. Two or three drops of each liquid suffice, and the whole operation is performed upon a glass slide, or in a, watch-glass. The woody parts of the section take a rich carmine, shading into orange, while the pith and light cellular tissue are stained a bright * Amer. Mon. Micr. Journ., iii. (1882) pp. 92-3. + Carmine stain: carmine 15 gr., ammonia 15 gr., distilled water 2 oz.; dis- solve carmine in ammonia over the flame of a spirit-lamp, add the distilled water and filter. Green stain: anilin green 5 gr., absolute alcohol 1 oz. dard ZOOLOGY AND BOTANY, MICROSCOPY, ETC. BTY orange-yellow. In a section (transverse) of the leaf-stem of the sago-palm, the outer cells, which are smaller and more compact than the more central ones, were dyed a rich orange-yellow, and their nuclei a bright carmine. The curious large ducts in the central portion of the stem, which, as a system, form in a transverse section a figure like the Greek capital omega, take a pleasing variety of shades, the cells around the edges being a bright orange, the central cells shading down to deep carmine. These sections of the midrib of the sago-palm are beautiful objects stained or unstained, and one of the best examples of curious cell arrangements to be found anywhere. The action of the dyes made from the above formula is quick and certain, and the effects very satisfactory. Cutting Sections of Coal.*—Some discussion has taken place as to the feasibility of the method mentioned in the ‘ Micrographic Dictionary, of macerating the coal in a solution of carbonate of potash, several authors finding that the coal still remained quite hard and impossible to cut. OC. L. Lord finds the following method to be easy and successful when tried on the particular kind of coal men- tioned by Huxley as containing macrospores and microspores in such abundance, viz. the Better-bed coal of Bradford and district. Grind achip of coal to a smooth surface on an ordinary school-slate. Then cement it to a glass slide, either with shellac or Canada balsam. If balsam is used, it must be evaporated until it is of such hardness that a dent can only just be made in it by pressure with the thumb-nail, then remelt it and fix the smooth surface of the coal to the slide. The coal may then be ground on the slate to such a thinness as to show the spores. The coal-matrix containing the spores cannot be ground sufficiently thin to be transparent, and if it could be so ground, it is doubtful whether there would be any organic structure perceivable. J. Walker selects from soft Iowa coal, some hard heads, so called (that is, hard lumps of coal in various stages of transition from good coal to charcoal), and well-preserved wood mixed with sulphide of iron. Breaking up these lumps and cutting out with a chisel the wood from the coal, which is the same as the coal without the bitumen, and breaking this in the proper direction, sections can be got both ways of the tissue, and when ground down thin make a good transparent object, or opaque with the condenser, when the sulphide of iron glistens like gold-dust among the woody tissue. W. H. Harris has tried repeatedly to get a good slide of ordinary — coal, and the outcome is one section only that shows any structure, and this was cut from ordinary marketable coal from [linois, U.S.A. A piece of the coal was cut about a quarter of an inch in thickness with a fret saw, placed in pure turpentine for some considerable time, and then in dilute Canada balsam, until it was saturated. The turpentine was allowed to evaporate, and by a gentle application of heat the balsam the section had absorbed was gradually hardened. One side was then ground flat, polished and cemented to the slide ; * Sci -Gossip, 1882, pp. 89, 136-7. Ser. 2.— Vot. II. 2 Q 578 SUMMARY OF CURRENT RESEARCHES RELATING TO when completed the other side was a simple repetition of careful erinding on a water-of-Ayr stone, just as an ordinary rock section would be treated, only with more care when the critical point was approached. Finally, Dr. C. H. Griffith, one of the editors of the ‘ Micrographic Dictionary,’ says he is “greatly amused at the discussion,” and suspects the writers “have been experimenting with the refractory anthracite coal too common in our coal-scuttles; but this being nearly all mineral matter, of course, does not yield to the action of the potash. Neither would it show much if so cut. They remind me of a former sapient microscope pupil of mine, who took to himself much credit for soaking a nail from the ‘ Victory, in the hope of making a section of it for the Microscope to show the structure. The coal for which this process is recommended, and which yields the best objects, is that which is more of a lignite character, and when so treated and digested with heat, is cut readily. Tomy own knowledge Professor Henfrey cut hundreds of sections in this manner.” Sections of Mica-schist.*—In a paper describing the methods he originally adopted for rock sections, Dr. H. C. Sorby says that it is possible to prepare thin secticns of mica-schist perpendicular to the foliation, although it is so friable that at first sight it appears im- possible. Having got a fairly thick portion and reduced it to about 1 inch, it must be wetted well with turpentine so that it may penetrate into the pores of the rock, and then covered over with Canada balsam and kept hot inside the fender. The balsam penetrates into the loose material, and thus supplies artificially what nature has failed to supply in not having hardened it sufficiently by infiltered quartz. It is well to repeat the process after a little time. By this means the weak points of the mica-schist and the planes of discontinuity are filled with hard Canada balsam so as to make it thoroughly hard throughout, and enable it to be rubbed down and the section left of the desired thickness. Paper Cells.;—Mr. W. H. Walmsley, in an article (the third of a series) on Dry Mounting, considers that the remedy for the appearance of moisture in cells is to be found in “ saerificing artistic cells of wax, with their pretty coloured rings of varnish, and being content with those of humbler and far more useful qualities. Paper, from which such dissimilar articles are now manufactured as love-letters and car- wheels, is our friend in need in this emergency,—not sized, or glazed, or calendered, but soft, porous paper of various thicknesses to suit our needs ; a thick blotting pad being exceedingly useful for cells containing objects sufficiently thick to require such a depth.” Wax Cells.t—Mr. T. Whitelegge proposes “a very simple method of making wax cells. A piece of glass tubing is first drawn out to a point so as to form a pipette, and this is filled with melted * North. Microscopist, ii. (1882) pp. 1384-5. Cf. also Mr. Rutley’s process, this Journal, iii. (1880) p. 849. t+ ‘The Microscope,’ ii. (1882) pp. 1-8. t North. Microscopist, ii. (1882) p. 194. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 579 white wax. The slip upon which the cell is to be made is placed on the turntable, and while it is spinning, touched with the point of the wax pipette, previously heated so that the wax may flow out readily. A wax ring is thus made quite as easily as one of varnish, and if the ordinary pharmaceutical white wax be employed, it will adhere very tenaciously to the slide. It is obvious that many varieties of rings may be made by modifying the temperature of the wax or even by warming the slide, and as an operation of this kind generally requires some little practice in order to obtain the best results, a few failures at the outset should not discourage the operator from further attempts.” Miller’s Caoutchouc Cement.—Mr. R. Miller, while not claiming to have discovered any new substance, has hit upon a new method of combination by which a material is obtained easy and quick to work and reliable in its results, and available both for making and sealing cells. It has stood a test of eighteen months. The following are his directions for using it :— To turn Cells. —Centre the glass slide on the turntable, and with a camel’s-hair brush previously charged with sufficient cement, mark off the foundation of the cell in width and size required, the turntable being somewhat rapidly revolved; dip more cement and apply directly before the first layer can set, and so on, always touching the top of the stream only, until the cell be raised to the height desired, then lay the slide aside in a level position to dry, Slight cells dry in a few hours, deep cells, say } of an inch, in two or three days. One hundred perfect cells may be turned in an hour by a beginner, and nearly twice that number by an adept. (Keep the brush clean and the bottle tightly corked.) To mount in Glycerine, Oil, Canada Balsam, or other Fluids,— Take a cell perfectly dry, apply or turn a sufficient layer of the cement round the top of the cell, slightly overfill the cell with glycerine, and put in the prepared object, place on the glass cover (previously tested to fit), press down the centre and edges of the cover until it is firmly in position, and with a damp brush gently remove the expelled glycerine ; test again by slight pressure that the cover is on the cement, and lay aside to set. A few hours afterwards the slide may be immersed in a basin of water and thoroughly cleansed with a camel’s-hair brush, wash again if necessary, and when thoroughly freed from all traces of glycerine and quite dry, turn a layer of the cement over the cell embracing the rim of the glass cover, and finish to taste. The slide will then be found to be durably sealed and the fluid permanently confined. These directions apply to mounting objects in oil or fluid Canada balsam, except the use of water to clean them; the supei- fluous oil or balsam must be removed by a brush dipped in benzole, the brush being continually wiped between a cloth. Do not use balsam diluted with ether or chloroform. Mounting in Phosphorus.—The following is the note which Dr. Morris has written out, as mentioned, post, p. 591. It must, 2 a3 580 SUMMARY OF CURRENT RESEARCHES RELATING TO however, be borne in mind that the sole advantage of phosphorus is its high refractive index = 2-1. If it is diluted to 1-7, no benefit is derived from its use over bisulphide of carbon or other substances whose refractive index = 1°7, and they should therefore be used in preference. Dr. Morris’s note, however, contains some useful hints. ‘‘Having seen several specimens of diatoms mounted in phos- phorus and bisulphide of carbon, I am under the impression that the solution is too strong for the purpose required, and as I have mounted some hundreds of slides in the strong and weak solutions, I have come to the conclusion that the weak solution is the best and safest for mounting minute objects, such as the Diatomacez. “The solution I use is made as follows :—Take one ounce of car- bon bisulphide and put it into a wide-mouthed stoppered bottle, and add about two or three drachms of phosphorus piece by piece, taking the precaution to previously absorb all the moisture from its surface by placing it on blotting-paper for a second or two. When all is dis- solved, filter through white filtering-paper and a glass funnel into another bottle (narrow-mouth stoppered), wash the filter with a little carbon bisulphide, and when filtered place the filter in a basin of water until there is time to burn it in the fire. “ Having made and filtered the solution, take a small piece of white blotting-paper about an inch square, and with a glass rod put a drop of the solution on the paper and watch the effect. If it flares up with a yellow flame it is too strong, and requires more carbon bisulphide added to it, but if it only smokes and carbonizes the paper the solution is of the right strength. See that the stopper is well fixed in the bottle, and put it away for a day or two. If any sediment has formed in the meantime, filter once more, using the same precautions with the filter as before. “Tf the solution is made according to the above directions, it will be always ready for use and keep for months. “To make cement for the cover-glass, take of good isinglass one ounce, put it into a saucer, add a few drops of water from time to time until the isinglass is moistened but not pappy. Put about two ounces of glacial acetic acid into a porcelain capsule, place it over a spirit- lamp, and bring the acetic acid to boiling-point. Add the isinglass by degrees until the whole is dissolved, keeping the mixture constantly stirred. Boil until a spot placed upon a slip of glass becomes solidified when cold. When sufficiently boiled, put it away in a wide-mouthed bottle, using a cork for a stopper. A small quantity for constant use may be kept in a two-drachm bottle. This must always be warmed in hot water before applying it. “The diatoms being fixed on the cover, see that the following articles are at hand :—A small bottle of carbon bisulphide, a glass pipette four inches in length terminating in a fine point, a few pieces of blotting-paper one inch by half an inch, small camel-hair brush, mounted needles, a small basin, and a turntable. “ First gently warm the slide, centre it on the turntable, warm the cover-glass and place it on the slide, wash the pipette with the carbon bisulphide, then with the pipette take up a small quantity of ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 581 the solution of phosphorus and allow it to run under the cover just sufficient to float it. See that there are no air-cells, if so, gently move the cover backwards and forwards to the mounted needles, when all the air-cells will disappear. Take the small brush, load it with the warmed cement, and touch the edge of the cover-glass at right angles in four places, then gently revolve the turntable, keeping the brush close to the edge of the cover until the cement ring is complete, then absorb the remainder of the phosphorus solution on the slide with the strips of blotting-paper, putting the paper into the basin of water so that it can do noharm. As long as the blotting-paper saturated with a solution of phosphorus is wet, no combustion will ensue. Hence the necessity of seeing that all which has touched the solution of phosphorus has either undergone combustion or been placed in the fire before leaving off work. “ The mounted slide may be again touched with the cement, when it can be put away until the following day. A ring of solution of sealing-wax or shellac may then be used to finish it off. If by acci- dent more of the cement has got on the slide than is required, when the ring of sealing-wax is hard, the cement can be washed off with a small brush dipped in water and applied gently. When dry it can then be finished off as the mounter may fancy. “ Always wash the pipette in the carbon bisulphide before and after using the solution of phosphorus. Latterly I have discarded the soft cell and always mount as described, because I found that the solution of phosphorus is very liable to form air-cells; or, in other words, there is a want of affinity between the glass and the medium, and if it is a valuable preparation it may be completely spoiled on account of the air-cells; whereas by doing away with the soft cell and mounting as I have described, the air-cells can always be got rid of before applying the ring of cement. “Diatoms are easily resolved in this medium, which in a dry or balsam mount are unresolvable.” Vacuum-bubbles in Canada Balsam.*—Mr. W. M. Bale says, “One of the first difficulties which a novice in mounting meets with arises from the formation of air-bubbles in Canada balsam, but experi- ence shows him that if the balsam be used in not too thick a state, any bubbles that may form in it will, unless they are excessively large, gradually disappear in the course of a few days at most, and henceforth air-bubbles in the balsam cease to be a source of trouble. It is otherwise, however, with vacuum-bubbles, which are apt to appear in any closed cavities of an object at the moment of applying the balsam, even though every cell may have previously been perfectly filled with turpentine or carbolic acid. The cause appears to lie in the different densities of the fluid and the balsam, the former finding its way out of the cell to mix with the balsam, while the latter, owing to its greater density, is unable to enter the cell and supply its place. A vacuum is therefore left, which has all the appearance of an air- bubble, and which may either take a globular form or expand till it * Journ. Mier. Soe. Victoria, i. (1882) pp. 103-4. 582 SUMMARY OF CURRENT RESEARCHES RELATING TO completely fills the cell. In the former case it is evident that the balsam is finding its way into the cell, though slowly, and if it is thin enough to retain its soft condition for a few days, the bubbles will probably disappear ; but when they completely fill the cell it is a sign that the balsam cannot find entrance, and the object can then only be cleared by again soaking it in the fluid solvent. Among the objects most liable to this inconvenience may be mentioned sections of some wood, also such Bryozoa as some of the common Catenicelle, the avicularian processes of which usually contain perfectly closed-in chambers. In the closed gonothece of some of the most delicate hydroids the same cause is followed by different results—the escape of the fluid and the inability of the balsam to enter, causing the collapse of the thin chitinous investment, instead of the formation of a vacuum-bubble, as is the case where the wall of the closed cavity is strong enough to resist the pressure of the balsam. Precisely the same phenomenon is observed when delicate vegetable tissues are placed in glycerine, and the means used to prevent it, viz. thickening the medium very gradually, suggested to me the idea of applying the same principle to balsam mounts. An easy method of doing this is to place the object in turpentine on the slide under a large cover-glass, and with a glass-rod, deposit round the margin an embankment of soft balsam, then lay the slide aside till the balsam and turpentine are thoroughly mixed, which will be a slow and gradual process, It is not advisable to use carbolic acid for this work, at least if there be any considerable depth between the cover and the slide, as the mixture of acid and balsam assumes a rather deep colour. A slight modification of this plan may be used with advantage to prevent delay in the drying of the slide, as follows: —Place the object (saturated with carbolic acid) in the middle of the slide, and make a little embankment of balsam at some distance all round it, then fill the space within the balsam with a pool of the acid, and place the slide under the cover till the acid and the balsam are sufficiently mixed (ten minutes or a quarter of an hour), then drop fresh balsam on the object and cover as usual. Turpentine is not suitable for this purpose, as it runs all over the slide.” Mounting Moist Objects in Balsam.*—Dr. Johnson (of Victoria) some years ago recommended as a means to mount Sertularians, Bryozoa, &c., that the objects should be boiled in water till all the air is removed, then drained, placed for a few hours in carbolic acid, and thence transferred to the slide and mounted in balsam. It will be found, however, writes Mr. W. M. Bale, “that the water contained in the interior of the specimens being taken up by the acid will, unless a large quantity of the latter be employed, or the objects be laced in two successive baths of it, be sufficient to cause a cloudiness in the balsam. Moreover, it is frequently undesirable to lose time by putting the object aside till the water and acid have completely mixed ; and to remedy these inconveniences, the object, after removal from the water, should be placed in methylated spirit, which will * Journ, Micr, Soc. Victoria, i. (1882) pp. 104-5. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 583 take the place of the water in a very few minutes, thence it may be transferred to carbolic acid and boiled in it for fifteen or twenty seconds, when the object will be ready for mounting at once. I use this method for all moist specimens, and find it of great advantage in enabling me to mount them without delay, besides which, the quantity of acid used or spoiled is comparatively small, its place being partially filled by the inexpensive methylated spirit.” Moisture in Dry Mounts.*—Mr. W. M. Bale adopts the following very simple plan of mounting objects to allow of the circulation of air through the cell. Take an ebonite cell, and if necessary trim the edge neatly with a file, then with a file or knife cut two opposite broad, shallow notches on that side of the cell which is to be under- neath ; then cement the cell to the slide, taking care not to allow the cement to fill the notches, which, being shallow, are quite unnoticed unless looked for. The object may be placed in the cell, and the cover cemented on at leisure. If a bright edge be required to the cell, it is only necessary to paint it with a thin solution of balsam or dammar, and no varnish ring on the cell is requisite (unless some other colour than black be desired), as the ebonite cell supplies in itself a sufficiently neat finish. Those who are in the habit of using the excellent slides made by glueing perforated wooden slips to strips of card, can easily provide for the circulation of air by making one or two small slits in the card bottom of the cell. To obtain the freest circulation of air through the cells it will be advisible to leave the slides in an open rack box till the cement is hardened, rather than to close them up at once in a cabinet. Dammar Varnish.{—This being, according to W. Pfitzner, pre- ferable to Canada balsam, he prepares the solution in the following way:—Gum dammar, benzine, and turpentine, are mixed in equal parts, and put in a warm place. As soon as complete solution has taken place, the clear liquid is poured off, and allowed to evaporate until of the required consistency. Dr. M. Flesch { adds that in Wirzburg, dammar varnish, as used by painters, is generally em- ployed. Cleaning Used Slides and Covers.§—Mr. F. Barnard recom- mends the warming of the slide over a spirit-lamp and removing the cover, which is at once to be dropped into a bottle containing methy- lated spirit of wine, to which has been added 25 per cent. of liquor potasse. Then scrape off as much balsam as possible with an old knife, and with a rag wetted with the above mixture clean the slide. Afterwards, a second rag wetted with the same liquid is used if necessary ; and while wet, the slides are dropped into a basin of water. It will then only be necessary to thoroughly wipe them with a clean cloth. Breathing on them will show at once whether they are clean or not. * Journ. Micr. Soc. Victoria, i. (1882) pp. 101-3. ft Morphol. Jahrb., vi. (1880) p. 469. t Zool. Jahresber. Neapel for 1880, p. 51. § Journ. Micr. Soc. Vietoria, i, (1882) pp. 106-7. 584 SUMMARY OF CURRENT RESEARCHES RELATING TO While the slides are cleaning, the cover-glasses should be soaking in spirit and potash. They may now be removed one by one, and wiped ona rag. If necessary, they can be so treated a second time; but in either case they are to be dropped while wet into clean water. In removing the covers it will be found that the spirit and potash has decomposed the balsam and any gold-size, black varnish, &c., upon them, and the dropping them while wet into the water prevents the adherence of any particles by the decomposition caused by it. _ Mr. Barnard has tried benzine, turpentine, and many other things, but nothing seems so expeditious ‘and cleanly as the mixture recom- mended, as it frees the slide from grease, which has to be done after using benzine or turpentine. There is a risk in leaving the covers in the bottle of spirit and potash too long, for fear of an injurious effect of the potash on the glass; but this has not yet happened, though they have been left uncleaned for a long time after being removed from the slides. Resolution of Amphipleura pellucida. — Mr. E. M. Nelson informs us that since the date of the December conversazione of the Society he has found that the exhibit he then made of longitudinal lines on Amphipleura pellucida (dry on cover-glass) was an error—the lines then shown were due to diffraction. - He has since observed true longitudinal lines on this diatom by a more careful adjustment of the vertical illuminator, and has assured himself that they are finer than the 10th band of Nobert’s latest 20-band plate, i. e. dng than 112,595 to the inch. The objective was Powell and Lealand’s ;4, homog. imm. of 1°43 N.A. Repeated countings of the transverse lines on the particular frustule examined show them to be at the rate of 96 in the :001 inch, and therefore capable of resolution by any immersion objective (of sufficient power) whose effective aperture exceeds 1-0 N. A., and con- versely incapable of resolution by any dry lens. Microscopic Examination of Wheat-flour.*—C. Steenbuch re- commends the following mode of preparing meal for microscopic examination and determination of the starch-grains, by which the elements of the tissue can be easily isolated. The process depends on the well-known fact that a solution of diastase transforms starch- paste into dextrin and maltose. In order to obtain a solution of diastase, 20 g. of ground meal are placed for an hour in 200 g. cold water and repeatedly shaken, and then filtered through a double filter. 10 g. of the specimen of meal to be examined are then thoroughly mixed with 30—40 g. of cold water, the mixture placed in a beaker, and stirred up with about 150 g. of boiling distilled water. At a temperature of 75°-80° C. the formation of paste begins. The temperature is now allowed to fall to 55°-60° C., and 30 c.cm. of the clear filtered extract of malt added. The mixture is then stirred up, and the temperature kept at 55°-60° in a water-bath for 10 minutes. * Ber. deutsch. chem, Ges. xiv. (1881). Sce Bot, Centralbl., x. (1882) p. 140. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 585 Destruction of Microscopical Organisms in Potable Water.* —Langfeldt, in seeking for a substance which would kill the living organisms without injuring the water for drinking purposes, found that citric acid (4 gram per litre of the water) killed all except Cyclops and those with thick epidermis, within two minutes. Public Lectures in Microscopy.t—In October last the French Minister of Agriculture and Commerce instituted a gratuitous course of instruction in micrography at the “ Ecole Supérieure de Pharmacie ” at Paris, intended for theoretical and practical instruction in the functions of microscopical experts. Anprews, R. T.—Mounting Entomostraca. [Inquiry for directions. } Sci.-Gossip, 1882, pp. 160. B., T. R.—Mounting Volvox globator. {Slides mounted in 1878 are as good to-day as when fresh, except a very slight loss of colour. They were mounted alive in glycerine jelly as cool as possible. Volvor mounted in Canada balsam have not changed colour at all.] North. Microscopist, II. (1882) p. 162. Bate, W. M.—On Mounting Diatoms in symmetrical groups. [ Post. Journ. Micr, Soc. Victoria, I. (1882) pp. 97-9. - = Notes on Dry and Balsam Mounting. [Supra, pp. 581-3.] Journ, Micr, Soc. Victoria, I. (1882) pp. 101-5. Barker, H.—Photo-micrography. [General directions for amateur beginners with dry plates.] Journ. Post. Micr. Soc., I. (1882) pp. 75-80 (1 fig.). Barnarp, F.—On Cleaning used Slides and Covers. [Supra, p. 583.] Journ. Micr. Soc. Victoria, I. (1882) pp. 106-7. Birce, E. A.—On a Convenient Method of Imbedding. [Ante, p. 428.] The Microscope, IL. (1882) pp. 55-7, from Amer. Mon. Micr. Journ. Borcker, E.—Ein neues Mikrotom mit automatischer Messerfiihrung (A new microtome with automatic knife-carrier). [ Post, Zeitschr. f. Instrumentenk., II. (1882) pp. 209-12 (4 figs.), Bourne, A. G.—On certain Methods of Cutting and Mounting Microscopical Sections. [Supra, p. 567.] Quart. Journ. Micr. Sci., X XII. (1882) pp. 334-7. Britrary, T.—Micro-fungi: wheh and where to find them. 12mo, Manchester, 1882, 92 pp. oe », Microscopical Study. (Brief general remarks. ] Rep. § Proc. Manchester Sci. Stud. Assn. for 1881, p. 4. Brooxs, W. K.—Handbook of Invertebrate Zoology for Laboratories and Seaside work. (Containing directions for studying the general anatomy, the micro- wees and the development of selected types of animal life, &e. 8vo, Boston, 1882, pp. viii. & 392 (202 figs.). C., O.—On Amphipleura pellucida. [Discursive—ending with an anecdote of an American microscopist who lived before the time of immersion objectives, and was a determined seeker after the resolution of this diatom, destroying his practice and reducing himself to poverty. “Weaker and weaker he grew in his * Chem. Centr., 1881, pp. 74-5; ef. Journ. Chem. Soc, Abstracts, xl. (1881) p. 1179. t+ Rey. Mycologique, iv. (1882) p. 199, 586 SUMMARY OF CURRENT RESEARCHES RELATING TO wild chase after the phantom lines till death overtook him one night as he sat in his barren room surrounded by glittering brass tubes and flashing accessories, and his last breath was spent in a feeble attempt to whisper faintly ‘ wider-angle.’ ”] Amer. Mon. Micr. Journ., III. (1882) p. 99-100. Cargutt, J.—Photo-micrography. Report of an address to the Camden Microscopical Society—post. | The Microscope, II. (1882) pp. 43-4. Core’s (A. C.) 24 sections of starch-bearing vegetables and starch-granules. [Description of some of the slides.] North, Microscopist, II. (1882) p. 195. Coomsss, C. P.—Cutting Sections of Soft Tissue. [Description of Coppinger’s and Dr. Rutherford’s Microtomes and the plans of Dr. L. Clarke and of Dr. Klein (or German histologists) for cutting sections without apparatus. ] Journ. Post. Micr. Soc., I. (1882) pp. 61-3. Dirret, L.—[Remarks on the paper of J. W. Stephenson, ante, p. 163.] Bot. Centralbl., XI. (1882) pp. 105-6. Eecerr, L., and M. Lessona.—Il raccoglitore naturalista, guida pratica per rac- eogliere, preparare, conservare i corpi organici ed inorganici. 2nd ed. (The Collecting Naturalist, practical guide for collecting, preparing, and preserving organic and inorganic bodies.) 8vo, Torino, 1882, 123 pp. Excocx’s Type-slides of Foraminifera. [Description of the slides, which contain 50 species arranged in squares with the name of each photographed in readable type. ] Journ. Post. Micr. Soc., 1. (1882) p. 104. Ermencem, EB. Van.—Démonstration de préparations de bactéries de la tuber- culose. (Exhibition of preparations of bacteria of tuberculosis.) [Supra, p. 574.] Bull. Soc. Belg. de Micr., VII. (1882) pp. eXvii.-cxxii. Fiemine, J.—Mounting Volvox in Glycerine Jelly. [Reply to T. R. B.—“TI boiled the Volvox in the jelly on the slide, the cover-glass being held in position during the boiling process by a rather loose clip.”] North. Microscopist, 11. (1882) p. 192. Freeman, H. E.—Spheraphides of Cactus. [Directions for separating them—they show best with a little light from below or with spot-lens.] Journ. Post. Micr. Soc., I. (1882) p. 94. GRiFrFitu, C. H.—Cutting Sections of Coal. (Supra, p. 578.] * Sci.- Gossip, 1882, p. 137. Harris, W. H.—Sections of Coal. [Supra, p. 577.] Sci.-Gossip, 1882, p. 137. Hitcucocsk, R.—Photographing with the Microscope. (Detailed directions for photographing with the dry-plate process. | Amer. Mon. Micr. Journ., III. (1882) pp. 88-92 (2 figs.). a 5, Aperture and Resolution. [Remarks as to alleged resolution of 152,000 lines to the inch (ante, p. 416 and as to the appearance of lines in an image being no evidence that the image is produced by lines, and that the presence of lines in a photograph does not prove that the object is a lined object. ] Amer, Mon. Micr. Journ., 111. (1882) p. 96. as » Pond Life. [Recommendation of Balen’s tubes. ] Amer. Mon. Micr. Journ., IIL. (1882) p. 116. See also Amer. Natural., XVI. (1882) p. 618. Houmes, E.—On the Continuous Observation of Minute Animalcula. [Post.] Sci.-Gossip, 1882, pp. 138, 160. £5 » Observations on Living Organisms. [Inquiry as to the means adopted by those who have been successful in the continuous observation under the Microscope of very small and active organisms. | Sci.-Gossip, 1882, p. 159. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 587 Hoimes, E.—Sections of Cval. {Comment on the notes of Messrs. Lord, Walker, Harris, and Griffith, supra and infra.] Sci.- Gossip, 1882, pp. 159-60. Jaco, W.—Crystals, Nos. II. and IIT. [Directions for preparing slides of Crystals, and for the Microscopical Examination of Crystals formed naturally. ] Knowledge, I. (1882) pp. 601-2 (4 figs.) ; II. (1882) pp. 20-1 (4 figs.). Kary, C. H.—Glass Cells, [Post.] Amer. Mon, Micr, Journ., III. (1882) p. 101. Kirron, J.—Cutting Sections of Coal. [Reply to C. H. Griffith, supra.] Sci.-Gossip, 1882, p. 160. LanpsBer, B.—Ueber Conservirung von Protozoen (On preserving Protozoa). (Supra, p. 575. ] Zool. Anzeig., V. (1882) pp. 336-7. Lessona, M.—See Eger, L. Lorp, C, L.—Cutting Sections of Coal. [Supra, p. 577.] Sci,-Gossip, 1882, pp. 136--7. MicuaE.’s (A. D.) Note on Polarized Light as an addition to Staining. [ Ante, p. 426. ] [| Brief notice of it—the writer considers that “ there is little doubt that sufficient use is nut made of the polariscope in the examination of tissues,’’] Journ, of Sci., TV. (1882) p. 374. Moore, A, Y.—-The differential Staining of nucleated Blood-corpuscles. [ Post. ] The Microscope, Il. (1882) pp. 73-6 (1 pl.) 91. 5 ms Resolution of Amphipleura pellucida. (Correction as to his claim-—not by ‘central sunlight,” but with “ the mirror central,” it being the rays of greater obliquity than 1:00 N. A. that really do the work. } The Microscope, II. (1882) p. 85. Norviincer, H.—Descriptions of Sections of 100 kinds of wood puartly European. Vol. x. (Vols. i—ix. 1852-80). [Cf. Bot. Ztg., XL. (1882) p. 287.] 16mo, Stuttgart, 1882. Nort, E. §.—{Finding of Amphipleura pellucida smaller than those of Moller in the ratio of 12 : 16, and the lines correspondingly finer.] Amer. Mon, Micr. Journ., III. (1882) p. 99. OLLARD, J. A.—[Preparing] Stellate Hairs of Deutzia. [Scrape the leaf carefully with a sharp knife and transfer to slide with camel-huir pencil. | Sci.-Gossip, 1882, p. 138. R.—The Microscope on the Druggist’s Counter. [Results of examination for adulterations.] The Microscope, II. (1882) pp. 16-17. Rerynoips, R. N.—A Mount for Low Powers. (“ Part section of a human heel cut from bottom upward ”—with directions for mounting. ] The Microscope, II. (1882) p. 76. Ross, W, S.—Aid of the Microscope in the Diagnosis of Diseases. The Microscope, II. (1882) pp. 30-1 from Western Medical Reporter. Rovumecukre, C.—Legons publiques de Microscopie. (Public Lectures on Microscopy.) [Title more properly belongs to a foot-note on the same page, translated supra, p. 585. The above note refers to Dr. Van Heurck of Antwerp having set up Swan lamps in his laboratory, and to his lectures on Cryptogamic Botany.) Rev, Mycologique, TV. (1882) p. 199. Setvatico, S.—Sur le développement embryonnaire des Bombyciens. (On the embryonic devel »pment of the Bombycide.) (Contains a description of the method employed for making preparations of embryos, supra, p. 570.) Journ, de Microgr., VI. (1882) pp. 220-1. Sorsy, H. C.—Preparation of transparent Sections of Rocks and Minerals (concluded), (Supra, p. 578. ] North. Microscopist, 11. (1882) pp. 132-40. 588 SUMMARY OF CURRENT RESEARCHES, ETC, STEPHENSON’s (J. W.) Process of Mounting Objects in Phosphorus, &e. [ante, p. 163.] [Brief notice of it—the writer considers that “ the operation should on no account be attempted by any but those accustomed to the use of dangerous chemicals.’’] Journ. of Sci., 1V. (1882) p. 376. See also Amer. Mon. Micr. Journ., III. (1882) p. 116. SreRNBERG, G. M.—Photo-Micrographs. [Principally comment upon C. H. Kain’s paper, ante p. 424, in regard to the brief time of exposure he found sufficient, with oil-light. Note by the Editor appended.] Amer. Mon. Mier. Journ., 111. (1882) p. 119. v3 a5 A Contribution to the study of the Bacterial Organisms commonly found upon exposed mucous surfaces, and in the alimentary canal of healthy individuals. [Contains Methods of Research, supra, p. 571.] Stud. Biol. Lab. Johns Hopkins Univ., 11. (1882) pp. 157-81 (8 photomicr.). StrowE.., C. H.—The Student’s Manual of Histology, for the use of Students, Practitioners, and Microscopists. 2nd ed. 8yvo, Detroit, 1882, 290 pp. and 192 figs. Srvert, T. J— What shall I do with the Microscope? [Directions for mounting the “ intestinal teeth of insects,” post. Engl. Mech., XXXV. (1882) p. 282. Tayior, T. W.—Double Staining with Carmine and Aniline Green. [Supra, p. 576.] L Amer. Mon. Micr. Journ., Tl. (1882) pp. 92-3. Wave-WiLtTon, E.—Letter as to his ‘ New Series of Living Specimens for the Microscope.’ Journ. Post. Micr. Soc., 1. (1882) pp. 106-7. WALKER, J.—Sections of Coal. [Supra, p. 577.) Sci.-Gossip, 1882, p. 137. WatmsLey, W. H.—Some hints on the Preparation and Mounting of Micro- scopical Objects, IIT. [Dry Mounting. (Paper Cells ef. supra, p. 578.) ] ; The Microscope, 11. (1882) pp. 1-8. Warren, R. S.—The Preparation of Diatoms. [Post.] Amer. Mon. Mier, Journ., II. (1882) pp. 111-5. West, T.—An Hour at the Microscope. [Six notes on diatoms, Sphagnum, spheraphides, Trichina, proboscis of tortoise tick, and egg of louse of Vieillot’s pheasant, with brief passing references in four cases as to preparing and mounting. Also note on irremovable black backgrounds, supra, p. 559.] Journ. Post. Mier. Soc., I. (1882) pp. 90-4. WHITELEGGE, T.—Wax Cells. [Supra, p. 578.] North. Microscopist, 11. (1882) p. 194. Witson, J.—Cutting Sections of Coal. [Records his failure with the bi-carbonate of potash process. Sci.-Gossip, 1882, p. 137. Wooster, W. H.—Line and Pattern Mounting. [Post.] Journ. Mier, Soc. Victoria, I. (1882) pp. 94-6. ( 589 ) PROCEEDINGS OF THE SOCIETY. Meetine or 147TH June, 1882, av Kine’s Conieae, Stranp, W.C., Tue Prestpent (Proressor P. Martiy Duncan, F.R.S.) 1n THE CHAIR. The Minutes of the Meeting of 10th May last were read and confirmed, and were signed by the President. The List of Donations (exclusive of exchanges and reprints) received since the last meeting was submitted, and the thanks of the Society given to the donors. From Cole, A. C.—Studies in Microscopical Science, Vol. i. Nos. 1 and 2, and two preparations in illustration 2 .. The Editor. Geologic: al Magazine, Vols. i—xviii. (1864-81) .. .. .. .. Mr. Crisp. Heurck, Dr. H. Van.—Synopsis des Diatomées de Belgique, Fasc. V. Crypto-Raphidées, 1° Partie, pls. 78-103 .. .. The Author. Hitchcock, R.—Synopsis of the Fresh-water Rhizopods. (S8vo, New York, 1881) 56 pp., with 4 pls. nowadded .. .. The Author. Jones, T. Rupert.—Catalogue of the Fossil Foraminifera in the Collection of the British i He pp. xxiv. aud 100. eye : London, 1882) . : .. The Trustees. Micrographic Dictionary. 4th ed. Part 12... cs ae Mr. Van Voorst. The President called special attention to the donation of a com- plete set of the ‘Geological Magazine, and Mr. Stewart referred to the ‘Studies in Microscopical Science,’ edited by Mr. A. C. Cole, the illustrations of which he considered were very good, and the letter- press appeared to be equally so. The novel feature was that a microscopical preparation accompanied each part. Mr. Crisp exhibited a j-inch objective by Tolles, with a very tapering front, and stated that it was claimed on Mr. Tolles’ behalf that he was the first to make such fronts about ten years ago. Mr. Ingpen said that he had one of Andrew Ross’s $-inch objec- tives with a triplet front, dated 1848, which was similarly tapered. Mr. Beck said that he had made them in the same way for the last . fifteen years. The President, referring to J. L. de Lanessan’s ‘Traité de Zoologie—Protozoaires ’ (8vo, Paris, 1882, pp. vii. and 336, and 281 fizs.), said that it treated of Amebe on a somewhat grand scale, par- ticularly as regarded the larger kinds, and he would suggest to some of the Fellows that they should search for these species as being of great interest. He obtained one from the Hampstead ponds which he © found full of minute refractile points. Mr. Stewart said he had examined some large Amebe, a short time ago, which came from Mr. Ingpen’s aquarium, and were crowded with refractile points. They were distinctly crystalline in character, and had a vesicular nucleus. 590 PROCEEDINGS OF THE SOCIETY. Mr. Hartog said that he used to find the nuclei in the large Amcebze with a very distinct network, although one which he found had a hollow nucleus. The President inquired if Mr. Hartog had ever been able to iodize Amecebee ? Mr. Hartog said he had stained them with picro-carmine, but had not done so with iodine. Dr. Ralph, the President of the Victoria (Australia) Microscopical Society, responding to a welcome from the President and the Meeting, said he should like to take the opportunity of bringing before the Fellows of the Society the examination of the leaves of various kinds of plants by means of the action of prussic acid and ammonia. ‘The process was a very simple one, it being only necessary to place the section under the Microscope, and then introduce the compound. He had only had time as yet to examine a few kinds of leaves in this way, but the vine had hitherto given the most marked instances of the chemical action to which he referred. A longitudinal section as thin as possible being made of the leaf and placed under the Microscope, the fluid should be added, and would be found to penetrate the struc- ture, chiefly acting on the ducts, which were within reach of the bark. In a few moments the most extraordinary colours made their appearance, such as claret, amber, port-wine colour, and others having all the appearance of a coloured injection of the tissue, only that in about a quarter of an hour it all disappeared. Other leaves which he ‘had tried behaved much in the same way, though they did not all respond to the reagent in an equal degree. It was only in the brittle sappy stems that it was possible to get the best results. In conse- _quence of these observations, he had been able to treat sections of the human subject with prussic acid with marked effects. Whenever he got in the plasma amorphous particles distinctly blue in colour, he also found the formation of amyloid bodies in the blood. These bodies were very well defined, and under favourable circumstances, in polarized light, the black cross could be seen. The production of amyloid forms by chemical means, not only under the action of hydro- cyanic acid, but by chloral, formic acid, or solution of copper in ammonia, was a point of considerable interest. If a portion of either of these reagents were added to fresh blood, and examined carefully under the Microscope, they would, in all probability, find these ~ starch-like bodies developed in the field. It was not easy to show the process in a room to a number of persons; but if any one present was interested in these subjects, he should be very glad to demon- strate what he had been describing. Mr. Stewart inquired whether these bodies were supposed to be . formed by the reagent, or were they supposed to be really present before, but only to be made visible by the reaction ? Dr. Ralph said that under favourable circumstances they might see a globule which they would be disposed to say was oil; when the reagent was added it would increase in size from about the step inch to about the 7,'55 inch; later it would suddenly become PROCEEDINGS OF THE SOCIETY. 591 opaque, and then it would colour in such a way that any one looking at it would say at once that it was starch. So far as he had carried out the observations, it seemed as if these starch-grains really did develope, and he thought it might be an instance of the commencement of the process of amyloid deposit. Dr. Morris, of Sydney, was introduced to the Meeting by the President, and detailed some experiments which he had made in mounting diatoms in phosphorus in such a way as not to be inflam- mable. As he had only just arrived from Sydney, he had not had time to write anything on the subject.* He had seen some of the specimens which had been mounted in England, and was under the impression that the solution was too strong. He proposed, therefore, to reduce it to such a strength that if a piece of white blotting-paper was put into it, it would not blaze up. By such a solution all difficulty as to using the medium was done away with, the only necessary pre- caution being to have a basin of water near at hand to dip the fingers into. Mr. Stephenson said that if they used a weak solution they would get a lower refractive index, whereas the principal object in mounting in phosphorus was to get as great a difference as possible between the refractive index of the medium and that of the object, for on this difference alone the increase of visibility depended. Mr. Crisp said that if phosphorus was used diluted to a refractive index of 1°7, the visibility of the diatom would be proportionately reduced, and as there was no virtue in phosphorus, except for its high refractive index, it would be better not to use it at all in such a con- dition, but to take some non-inflammable substance which had the lower refractive index. Dr. Morris said that, with regard to the value of the process, he might mention that he had tried some Navicule, and that with an oil- immersion lens the object mounted in phosphorus was resolved in the most perfect manner—far superior to anything that could be seen with balsam. Mr. Crisp said that it must be borne in mind that the danger inci- dental to the use of phosphorus was not confined to the process of mounting. A case recently occurred in which an_ object-glass, brought down too hard, broke the cover-glass, and the observer, having wiped off the exuding phosphorus with his handkerchief, put it into his pocket and set himself on fire. Mr. Ingpen exhibited and described some high-power achromatic eye-pieces, by Steinheil, of Munich (Series A F). They were con- structed for astronomical purposes, but he thought they would prove serviceable for use with the Microscope. Those exhibited were of 3,14, and } inch focus, each having a field of 40° (see p. 551). Mr. Ingpen said that, whatever differences of opinion there might be as to * See note by Dr. Morris written after the meeting, supra, p. 579. 592 PROCEEDINGS OF THE SOCIETY. the value of deep eye-pieces, there was probably none as regarded the desirability of securing the best possible definition, whatever amplifi- cation was used. He considered that with Huyghenian eye-pieces of less than an inch focus there was a serious deterioration of the image. The eye-pieces now exhibited gave the sharpest definition of any of similar foci he had hitherto been able to examine. Mr. Crisp explained the new method devised by Dr. Ehrlich, the assistant of Dr. Koch, for preparing the bacteria of tuberculosis, which constituted a considerable improvement upon the original process. It produces a more intense colour in the bacteria, so that they appear larger, and can be recognized with a lower power, even, it is said, of 250 diameters (see p. 572). Prof. Abbe’s process of increasing the consistency of pure cedar- oil, so as to render it less fluid and therefore more convenient for use aS a homogeneous-immersion fluid, was explained by Mr. Crisp. The oil is spread out in thin layers, and exposed to the action of the air and light for a long time, until it becomes of the consistency of castor-oil (see p. 551). Mr. W. F. Petterd’s letter was read accompanying a collection of diatoms from Tasmania. Mr. A. Certes’ letter, reiterating his claim to the discovery of a method of staining the nucleus of living Infusoria, was read by Mr. Crisp, who said that the author of the interpolation by which such a claim was described as “ erroneous,’ now agreed that he was mistaken in the view he had expressed, not having in fact sufficiently noticed that the claim related essentially to the nucleus of the living animals (see p. 576). My. Crisp called attention to a process devised by EH. Korschelt, of Freiburg, for preserving Infusoria and Amebe by the use princi- pally of osmic acid and chromic acid, no method having hitherto been found for the latter organisms. Dr. A. Gruber had also succeeded in preserving Heliozoa by the method, in excellent condition (see p. 574). Mr. R. Miller’s description of his caoutchouc cement for making and sealing cells was read, in which he stated that he did not claim to have discovered any new material, but to have accidentally hit upon a new method of combination. The material so obtained was singularly easy to work, and reliable in its results (see p. 579). Dr. Van Heurck’s letter was read describing favourably his further experiences with the Swan electric lamps and Faure-Reynier accumulators (see p. 557). PROCEEDINGS OF THE SOCIETY. 593 Professor Abbe’s note was read with reference to the description of his camera lucida, anée, p. 261, in which he stated that the benefit of the arrangement consisted simply in the ease with which it may be used. In other respects it did not possess any advantage over those forms which fulfil the condition that the image is seen without reflection or other loss of light. Mr. Ahrens exhibited and explained the construction of his new erecting binocular Microscope. In general outline it presented much the same appearance as that of Mr. Stephenson, the tubes being inclined, whilst the stage was horizontal. The erection of the image was, however, obtained by introducing a Nachet erecting prism over the objective, another prism similar to the Wenham being used above to divide the pencils. Dr. Millar said that, whilst he could speak with great praise of the advantages of the erecting binocular as an instrument to work with, leaving nothing to be desired for comfort and convenience, he thought the one now before them did not appear to give an entirely satisfac- tory stereoscopic effect. Mr. Michael said there was no doubt that a binocular Microscope, with a flat stage and an erecting arrangement like that of Mr. Stephenson, was an immense help to those who worked at living objects. In drawing from living insects he had found it of the greatest practical service. Professor Liversidge’s communication on the “silver-fish” of Sydney was read, in which he defended the accuracy of the observa- tions of Hooke recorded in his ‘ Micrographia * (1665) as against the strictures of Mr. W. Blades in his ‘ Enemies of Books’ (3rd edition, 1881). Specimens of the insects were sent, and labels and sheets of paper destroyed by them exhibited (see p. 500). Mr. Hartog said there was no doubt as to the animal being Lepisma saccharina, the same that was often found in this country. It was mentioned by Emerson Tennant as being thought by some to prey upon books, but the author was of opinion that it rather preyed upon the insects which were found in the books, a view which he (Mr. Hartog) considered an error. _ Mr. Thom’s letter on Saccharomyces was read, in which he men- tioned that he had devoted all his spare time for ten years in tracking pu organisms, and now made all his bread without any yeast, so called. Mr. Bennett, to whom the letter was addressed, made some remarks upon the subject. Mr. Badcock’s note was read (in his absence from illness) as to his observation of eyes in the adult forms of Melicerta ringens, M. tyro (or tubicularia), and Stephanoceros Eichhornii, also as to the de- velopment of the latter form from the egg. He also pointed out that Ser. 2.—Vo. II. 2B 594 PROCEEDINGS OF THE SOCIETY. the tube with advancing age got filled up with mucilage, until only - just room enough was left for the creature to move up and down (see pp. 845-6 and p. 512). Mr. Badcock’s note was read as to a criticism by Professor O. Bitschli of his paper on Acinetina (this Journal, IIT. (1880) p. 561), which had appeared in the ‘Zoologischer Jahresbericht’ for 1880 (p. 173). Professor Biitschli, in remarking on Mr. Badcock’s eompa- rison of the finely ciliated newly-born Podophrya quadripartita to Megatricha partita, referred to the latter as a Rotifer(!), being appa- rently surprised that such a comparison should have been made. At first Mr. Badcock was puzzled to know how the reporter could have fallen into such a mistake, but it had sinee occurred to him that the explanation was to be found in the fact that there were Rotifers named Megalotricha, and although these were very large Rotifers, while Megatricha is one of the most delicate of all the Ciliata, it was most probable that this was the origin of the mistake. Mr. Wilson thought it was strange that Professor Biitschli, who was a very eminent authority on the Protozoa, should not have been familiar with Megatricha, as appeared to be the case. Many of the reviews in the ‘ Zoologischer Jahresbericht’ were, however, obliged to be hastily done, and some excuse must be made on that account, as well as for the fact that the reporters had to deal largely with papers written in foreign languages. Professor Abbe’s paper “On the Relation of Aperture to Power,” Part II., was laid before the meeting by Mr. Crisp, who said that as it was a very long communication, he had prepared a résumé, which pre- sented the leading points in a condensed form suitable for being read to the Meeting. This he was proceeding to do, when Mr. Beck, interposing, said he thought that as the paper was an important one, and required a good deal of consideration, a résumé of it would be of very little use to them. He would suggest, therefore, that the paper should be printed, and that when it had been before them in eatenso, an evening should be specially devoted to its con- sideration and discussion. The Chairman (Mr. Glaisher, in the absence of the President), on the contrary, thought that it would be very useful to have an abstract of the paper read. Mr. J. Mayall, jun., also thought it very desirable that the Society should be in possession of Professor Abbe’s views, without having to wait until the next issue of the Journal. The Meeting having indorsed this view, Mr. Crisp read a résumé of the paper (see p. 460). The Chairman said that the paper was obviously one of very con- siderable importance, and he had great pleasure in proposing that the warm thanks of the Society should be presented to Professor Abbe for it. Mr. Stephenson seconded the suggestion, and said that, having PROCEEDINGS OF THE SOCIETY. 595 had the advantage of reading the paper in MS., he was able to say that it contained a most exhaustive discussion of the subject. Mr. Crisp said that it was the first attempt that had been made to establish a definite relation between aperture and power, and amongst other benefits it could not fail to prevent the perpetration in future of such absurdities as had been issued in the way of low-power objectives with very large aperture. The Chairman said that the report of the committee appointed to consider the question of standard gauges for eye-pieces and sub- stages had been adopted by the Council. The gauges recommended for eye-pieces were 1°35 inch and 0:92 inch, and for substages 1-5 inch. The following is the report of the committee :— “The committee who were appointed under a resolution of the Council directing them to ‘consider the advisability of establishing standard gauges for eye-pieces and substages,’ after communication with the leading opticians and with Fellows of the Society, now present their report as follows :— “The committee have found that a very general desire exists on the part of workers with the Microscope that there should be standard gauges both for eye-pieces and substages, and the com- mittee therefore resolved ‘ That in the opinion of this committee it is expedient that standard gauges should be established for the eye- pieces and substages of Microscopes.’ “In considering the question of the number of standards to be adopted, the committee were of opinion that it would not be prac- ticable to establish a single uniform gauge for eye-pieces. On the one hand, a considerable number of Microscopes issued are of small size, and could not with convenience be fitted with a body-tube of large diameter ; while, on the other hand, it would be undesirable to reduce the diameter in use with first-class instruments. The same considerations do not apply to the case of substages, which are frequently of as great a diameter in the smaller instruments as in the larger. The committee, therefore, resolved to recommend ‘ That the standards for eye-pieces should be two in number, with a single standard for substages.’ “ With regard to the size of the standards, the committee did not feel themselves able to treat the question as one entirely open, but considered that it would be preferable to select some sizes already in general use, so as to involve the minimum of change. They there- fore resolved to recommend ‘That the two standard gauges for eye- pieces should be, for the No. 1, 1°35 inch, and for the No. 2, ‘92 inch (external diameter), and that the gauge for the substages shculd be 1°5 inch (internal diameter). The No. 1 gauge is generally used for the larger instruments in England, whilst No. 2 is that adopted by many Continental makers.” Mr. Crisp said that it should be mentioned that there had been some difference of opinion, both on the part of the committee and the Council, as to whether there should not be a third intermediate 596 PROCEEDINGS OF THE SOCIETY. gauge; also, that in selecting the sizes mentioned by the Chairman, regard had been had to those which were at present in most frequent use, so as not to disturb existing arrangements more than could be helped. The following Papers were taken as read :— “ Plant Crystals,” by Dr. Aser Poli, of Rome. “Note on the Rey. G. L. Mills’ Paper on Diatoms in Peruvian Guano,” by Mr. F. Kitton. “On the Estimation of Aperture in the Microscope,” by the late Mr. Charles Hockin, jun. The following Instruments, Objects, &c., were exhibited :— Mr. Ahrens :—New Erecting Binocular Microscope. Mr. Bolton :—Spawn of Perch. Mr. Crisp :—(1) Balkwill’s Slide of Foraminifera. (2) Hardy’s Compressorium (see p. 553). (3) Malassez’s Compte-Globules (see p. 559). (4) Tolles’ 4-inch objective with very tapering front. (5) Tolles’ Camera Lucida (see Vol. III. p. 527). Mr. Ingpen:—Steinheil’s High-power Achromatic Hye-pieces, 3-inch, 4-inch, and 4-inch. Prof. Liversidge :—“ Silver-Fish ” (Lepisma) from Sydney, N. §. Wales. Mr. R. Miller :—Caoutchouc Cement. Dr. Ralph :—Vallisneria from Melbourne. Dr. G. M. Sternberg :—Photographs of Bacteria (see p. 571). New Fellows.—The following were elected Ordinary Fellows :— Messrs. William Borrer, jun., William EH. Pickels, John Rookledge, Thomas C. Squance, M.B. and M.S.,and Prof. Albert H. Tuttle, M.Sc. (At p. 443 for Henry Pocklington read Christopher Pocklington.) Watter W. REEVEs, Assist.-Secretary. Fs The Journal is issued on the second Wednesday of " February, April, June, August, October, and December. me ee 7, Ser. II. To Non-Fellows,-*S Vol. 11. Part 5. OCTOBER, 1882. +. Price 46. 3 JOURNAL OF THE ROYAL MICROSCOPICAL SOCIETY: CONTAINING ITS TRANSACTIONS AND PROCEEDINGS, AND A SUMMARY OF CURRENT RESEARCHES RELATING TO ZOoOoLoGyY AND BOTAN DT (principally Invertebrata and Cryptogamia), MICROSCOPY, &c. Edited by FRANK CRISP, LL.B., B.A., One of the Secretaries of the Society and a Vite-Presidént and Treasurer of the Linnean Society of London ; WITH THE ASSISTANCE OF THE PUBLICATION COMMITTEE AND A. W. BENNETT, M.A., B.Sc., F, JEFFREY BELL, M.A,, Lecturer on Botany at St. Thomas's Hospital, Professor of Comparative Anatomy in King’s College, 8. O. RIDLEY, M.A., of the British Museum, asd JOHN MAYALL, Jox., FELLOWS OF THE SOCIETY. ; ee A WILLIAMS & NORGATE, | Bed LONDON AND EDINBURGH. MG ‘JOURNAL ROYAL MICROSCOPICAL SOCTETY. Ser. 2.—VoL. Il. Part 8. . (OCTOBER, 1882.) oe CONTENTS. — TRANSACTIONS OF THE Soonmty— | oe Pie Pale XIV —Puant-Crvstats. By Dr. Aser Poli Pat VL) ep eh 2 BOT ie, Summary. or Currant RESEARCHES RELATING TO ~Zoonoey AND 3 i Borany (pRrnoreanty InvERTEBRATA AND Cryprocamia), Mroro- SCOPY, &c., INCLUDING Diente Communtoations FROM FELLows shee me AND OTHERS... 0 oe su te ee oe ae ae a tee “HO0L.<. Woswnex: ‘Symbiosis of Dissimilar Organisms: «« DM ne NR ANY aes ONY De Electric Organs of Gymnotus soa ee oe pe de he ee oe oe Intracellular Digestion’ 6s wa 60 ee pe ee ae oe ee na Nervous System of Molluscd se ee ee ne we pe te be we North-American Cephalopods .. «. Fa ee pb ee homt cae an wae erom oat Marginella and the Mila en ak IN Pern EEO FRR cle soto fnay one Vascular System of Naiadesand Mytilidz .. ss + on ae a oh Sexuality of the Oyster 06 se oak ou i ee tae wy eel) 8 96 pail Respiratory Movements of Insects 2. ss oe ante ay we ee a Location of Taste in Insects ‘4 se. ou) nee an eae aaa oe Parthenogenesis in the Bees. es ee ve ne ae a ae Eye of Chloe diptera. . ces oe ew, we) BD ee Waleed oa eye Marine Caddis-fly — .. £5 RPE Gel Nya re wae tener ean ALO sc Oe Respiratory Organs of Arachnide (Figs. POG =AID oly Henk ae a eek ee ae OL y Habits of Scorpions «ss PR Pa pet ed nF Oe ay op ehr) x yuN Nei 8s _ Nest-forms of the Furrow Spider A ihpe iene EOP er ah cris Sey Mere Parthenogenesis in the House Spider -. «+s Pe ae Ue meres cise | on Segmentation in the Mites... .5 Seu oe ne be) gm, Tae ae Soed we Perception of Colour by Crustacea 00 +1 ve ae) 3 re Mediterranean Crustacea .. <1 ae bs as we ey North American Crustacea, 96 ee sé woh eteits. ae Bes Lee wee New Copepoda... Avi: aie poate) elghedy a} ; Development of Aninelios it oS ee ee a x Development of the Central Nervous ‘System of Annie Sa Wes Cage ae, bet Coral-reef Annelid oe oe eo oe eo ee oe : oe oe ; ee’, Muscular Téssue of the Leech Pisa Ses ROP eRe TAT a GS bait vat ae aye aires AE Observations on the Dicyemid@ wo. se se 0s soe ee ee eee Orthonectida:. oe ; ee a ee ee oe C6 CROs Oe. : New Rotifer: (Cupelopagis bueinedac) dae Fle? Hae ai scae BM vem ae ancl ee Anatomy of Echinoids .- .. ais ae, cilia 8: BY ARTA ale hh BR tote are Anatomy of Spatangus oie oe oe rs 6s oo eon. eo oe we va Development of Asterina gi cise oe Ni ed < Ge Cha eel Came! Vel use ee oe Brisinga . ee oe oo! oe oo pe Paes eo! ‘ee os 44 Anatomy: of ‘Holothnniaina iis sks cane © oho Caanes See ae eat Tissues of Siphonophora ~:. s+ se ee on oe oe oe | we wee | Development of Tubularia cristata ., + oe 40 an ny we we at Oe American Acaleph +. > 25) 06 ae ee oe he oe an ae ae OSE Sense of Smelt am Actiniz eo ot. oe ta f)08 ee: oe. ee iy ae See, x ‘ Ye 8 ee ‘Suuuan oF Cone Resranours, &¢e.—continued. «PAGE Ciliation of the Hypotrichous ee NERS ta Orit, ihear en aetihe Pee btn (815 e Species of Vorticelle .. -. den Aen eg rea aie hart has OO 4 Acinetide .. f RPM Ma. oe eset Swe onto ORO New Lype of I Porcellanous Foraininifera:. ae Pagina, Wide Wee Cea OOD Bacterium rubescens Lank. = Monas Okenti yas RRM ray Domed aT “ Oviform sire i or Coceidia SNe Se Tikes, Minty Poa eee ee ths pies RORS Borany.. 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Flint glass ' Crown glass Rock salt Canada balsam Linseed oil (sp. gr. +932) Oil of turpentine (sp. gr. +885) Alcohol Sea water Pure water Air (at 0° C. 760 nm.) en: DIsPERSIVE. POWERS. Diamond : Phosphorus Bisulphide of carbon Flint glass ‘|| Crown glass" aie eee Rock galt Canada balsam. Linseed oil (sp. gr. +932) Oik of id eta ay Gap: gr. *885) Alcohol ek Sea. water Pure water . Air @.) Ponarmine Anerns Diamond ‘Phosphorus Bisulphide of earbon Flint glass . Crown glass — Rock salt Canada. balsam Linseed oil (sp .g7.°932) Oil of turpentine (sp. gr. “886). Alcohol Seawater Pure water AAT? (Exact data for these tables are. at present wanting.) OBJEC- TIVES. Fooau LunGrn. 3 in.’ pin z Maanirving Powrr. Se AO 5). . V. Table of Magnifying Powers. EYE-PIECHS. . . Beck's 2, “ o£ . - E Ee BAA Beck's 1, }Powell’s 2, 3 eA Beck’s 4, Becks A Powell’s 1, and Powell 33.|-Ross’sC. Beck 5.3. | Powell’s A, Ros 3B, Powell Ss 6 Ross! Ss F. Ross’s A} Ross’s B, | ~ Ross’s‘D. } Bs. nearly.* ppora ed (peewee ~ Focan Lexar, ~~. As : SB ate 2 in. | + in. I 1 in. Vacwmme PowsR,. Le 4 — 4 10 | 80 “yay 5. is 7 AMPLIFICATION oF OBJECTIVES AND. EYEPIECES i soe egraeecynes ea Bern & 39k ARS ) 5 100 150 © 1873 |. 2007) CS O05 ERS ; 800 5 peor 375 450. |- 500 12600 Ee Beis 5) a G8 || = QUOC % 12 0: ~ 1050 4 1400" 1200. 1350. 1500 1650 7- | 1800 1950 2100 2250 > 2400. 4° 2 2550 2700 2850, 3000 3750: - 4500 6000 7500 . 9000 10000:* |) 12000 ; Seed + Sie | W. EMIL BOECKER, MANUFACTURING OPTICIAN, WETZLAR, GERMANY, SENDS GRATIS His CATALOGUE OF MICROSCOPES, OBJECTIVES, MICROTOMES, AND APPARATUS FOR SCIENTIFIC RESHARCH. Heinr. Boecker’s Microscopical Institute, at Wetzlar, Germany, MICROSCOPICAL PREPARATIONS - fm all branches of Natural History. 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P. COLLINS, 158, Great Portland Street, London, W. THE ‘“‘SOCIETY ’” STANDARD SCREW. The Council have made arrangements for a further supply of Gauges and Screw-tools for the “ Society” Sranparp Screw for OssEctTrves. _ Assistant-Secretary. _. The price of the set (consisting of Gauge and pair of Screw-tools) is 12s. 6d. (post free 123. 10d.). Applications for sets should be made to the For an explanation of the intended use of the gauge, see Journal of the — Society, I. (1881) pp. 548-9. ADVERTISEMENTS FOR THE JOURNAL. Mr. Cranes BLENCOWE, of 75, Chancery Lane, W.C., is the authorized Agent and Collector for Advertising Accounts on behalf of the Society. ~ i AES Ce ee ea ae HENRY CROUCHS _ First-Class ‘Microscopes. Student’s ‘Microscope. . New Family and School Microscope. Bie New Series of Objectives, Mew Accessories, MS NEW ILLUSTRATED CATALOGUE, ON RECEIPT OF STAMP. MAILED ABROAD sae HENRY CROUCH, 66, Barbican London, BO. AGENTS IN AMERICA, JAMES W. QUEEN & 00., 924, Chestnut Street, Paap U, 8 JOURN.R MICR. SOC. SER T.VOLM. PLVI. West Newnan & OC? se. JOURNAL OF THE ROYAL MICROSCOPICAL SOCIETY. OCTOBER 1882. TRANSACTIONS OF THE SOCIETY. XTV.—Plant-Crystals. By Dr. Aser Pott. (Read 14th June, 1882.) PuateE VI. PLANT-ORYSTALS were first observed by Malpighi,* and afterwards by all phytotomists. But the earliest researches on their composition and anatomical distribution in many plants were made by Sanio (1857). Gulliver has also published, from 1859 to 1880, several papers on plant-crystals, and especially on their classificatory signifi- cance, but I am sorry to have found his works very little known, although they contain a great many very important observations. Holzner (‘ Flora,’ 1864-69) studied the chemical composition, the crystalline shapes, and physiological significance of plant-crystals ; and the other authors who have dealt with the subject are quoted in my work ‘I cristalli di ossalato calcico nelle piante,’ Roma, 1882. I. The Composition of Plant-crystals—We may say that almost all plant-crystals are of calcium oxalate. There are crystals of calcium phosphate and tartrate, of potassium oxalate, EXPLANATION OF PLATE VI. Fics. 1 and 2.—Rosanoff crystals in Vercurialis annua L. Fic. 3.—The same in the pith of Canothus Africanus L. 3bis.—The same in the pith of Lavatera arborea L. » +£.—Crystals of Salvia rectiflora Vis. 5.— Crystals of S. janthina, Otto et Dtetr. » 6.—Crystals of the Solanacez. » 7—Vertical sections. A, in a female flower of Ricinus; B, in a male flower; c, crystals; j, fibro-vascular bundles; p, peduncles; s, sepals; /, petals. 5, 8.—A, transverse section of the petiole of a seed-leaf of young Ricinus ; B, vertical section of the same; g, glands; f, fibro-vascular bundles; ¢, vessels; c, crystals. * Opera omnia, Lugduni Batayorum, 1687. Ser. 2.—Vot. I]. 28 598 Transactions of the Society. &c., but they are distinguished by their solubility in water, or in _ acetic acid. All plant-crystals which are insoluble in water and acetic acid, and soluble in mineral acids, are composed of calcium oxalate. There are no crystals of calcium carbonate or sulphate in plants.* Holzner has given a table for distinguishing the crystalline formations in plants by chemical reactions. II. Crystalline form of Calecwm oxalate.—Calcium oxalate crystallizes in the tetragonal system, with three molecules of water ; in the monoclinic system, with one molecule of crystalliza- tion water. The octahedronsare generally tetragonal (e. g. crystals of Begonia, Tradescantia, &c.); the short prismatic crystals, the raphides, and all those crystals which were believed to be of sul- phate of calcium (e. g. the long prismatic crystals of Irds), are mono- clinic. Ill. Forms of Plant-crystals.—The various forms of plant- crystals have been described by Gulliver, who distinguished four principal forms: raphides, sphzeraphides (drusen of the Germans), short prismatic crystals, and long prismatic crystals. The raphides have been the principal object of Gulliver’s researches. They are frequent in Monocotyledons, and are found also in some families of Dicotyledons. Gulliver has described them in Vitacez, Balsaminacez, Galiacese, and Onagracese, and in numerous other orders of plants, but in the British Hxogens so confined to the last three orders as to be characteristic of them ; Hydrangea, by its raphides, he finds sharply distinguished from the Saxifragaceze, under which order it is usually placed; and Montinia by its want of raphides as plainly differing from its assigned order, Onagraceze.} The other crystals may be found free and abounding in the cavities of plant-cells, or one in every cell. The little prismatic, or tabular crystals, and the simple octahedrons, which are in many Gesneriaceee, Bignoniacese, Scrophularineze and Labiate, belong to the first case. ‘To this also belongs, I think, the crystalline powder of Sambucus and of many Solanaceze. ‘To the second case beloags the greatest number of plant-crystals, especially those which are grouped in druses (very common in the pith and bark of ligneous plants) and the short prismatic crystals of the bast-cells. * But see Beale’s ‘How to work with the Microscope,’ 5th ed. p. 174, plate xlvii. for Gulliver's description and figures of spheraphides of carbonate of lime.—Eb. + See “Bemerkungen zum Referate iiber Gulliver’s Liste krystallhaltiger Pflanzen,” von Prof. Dr. Georg Holzner, Zeitschr. f. Mikrosk., i. (1877), Heft 2, pp. 42-44, £ See this Jourral, iii. (1880) p. 44; and Quart. Journ. Mier. Sci., 1866, and on Pollen, &¢., in Pop. Sci. Review, 1868. Plant-Crystals. By Dr. Aser Poli. 599 A very interesting form is that of crystals which are surrounded by an integument of cellulose, and fixed by this to the walls of the cell (see Pl. VI. Figs. 1, 2, and 3). They were seen first by Rosanoff (Bot. Ztg., 1865,) in Ricinus and Kerria Japonica, and afterwards in many Aracez, in the fruit of Rosa (by Poulsen, who named them Rosanoff-crystals), in the pith of many Malvacez (Sida, Hibiscus, Lavatera, &c.) in the Rigellaria Africana, Mer- curialis annua, and some Celastracee and Rhamnex. These ligaments of cellulose are perforated, tubiform, and in the Malvacese they are found also in the cells which do not contain crystals, but in continuation of ligaments which surround the crystal of the contiguous cell (Fig. 3 bzs). Crystals are found also in the walls of cells, in the epidermic cells of many species of Sempervivum and Mesembryanthemum, and in the fibres of liber of many Coniferze (Solms-Laubach and Pfitzer). IV. Plant-crystals as a Taxonomie Character—Crystals are not frequent in Cryptogamez and Gymnospermee ; but in the Angiospermz they form the constant character of many families and groups of plants. Gulliver has proved the constant presence of erystals. and especially of raphides, in certain plants. He has found raphides in many orders, of which examples occur in Vitacew, Mesembryanthemez, some Nyctaginex, in Balsaminaces, Onagra- ceze, and Galiaceze ; and in the British flora he defines the Bal- saminacez as Geraniales abounding in raphides, the Orchidacese as Gynandrous Endogens abounding in raphides, and Galiacez as Corollifloral Exogens abounding in raphides. Vesque* has found that the presence of raphides is a constant character of Dilleniacez. We may then define Dilleniaceze as Ranales with raphides. In the Lemnacee the genus Lemna contains raphides, the genus Wolfia is wanting in raphides. Vitaceze contain every form of crystals in the stem, leaves, and fruit. Almost all ligneous plants contain spheraphides in their pith and bark, and short prismatic crystals in the bast-fibres and sometimes in the wood (Clusia). Celastracee and Rhamnez contain Rosanoff-crystals in the pith and the bark (Fig. 3). The bark and pith of many herbaceous plants (e.g. Dabiatz), contain free, abounding, little erystals. Many Monocotyledons contain only raphides (e. g. Orchi- dace, Narcissus, many Liliacee, &c.) ; the [ris has long prismatic erystals, Araceze raphides and spheraphides. (in my above- mentioned work there is a list of plants which contain crystals.) Y. As to the physiological function of crystals in plants we know very little. It seems that oxalate of calcium is a useless product of plants, because it is often eliminated from the plant by the fall of dead leaves and old bark; it is generally accumulated * Vesque, “ L’Anatomie des tissus appliquée 4 la classification des Plantes,” Nouvelles Archives du Muséum d’Hist. Nat., iv. (1881).. 28 2 600 Transactions of the Society. in those parts of the plant, every function of which has ceased, and where it is formed it remains, and is not dissolved again. (In Dr. Beale’s work above cited, are observations by Gulliver on the uses of plant-crystals.) In the herbaceous plants, crystals abound in the axis of the inflorescence and stalks of flowers; and in Ricinus I have observed that there are an abundance of spheraphides in the female flowers, while they are almost wanting in the male flowers (see Fig. 7). In small plants of Ricinus, crystals appear first in the glands of cotyledonary leaves by the side of the spiral vessels (see Fig. 8). ( 601 ) SUMMARY OF CURRENT RESEARCHES RELATING TO ZQO0Q0LO0GC-Y° AND B@TiA NY (principally Invertebrata and Cryptogamia), MICROSCOPY, &c., INCLUDING ORIGINAL COMMUNICATIONS FROM FELLOWS AND OTHERS.* ZOOLOGY. A. GENERAL, including Embryology and Histology of the Vertebrata. Symbiosis of Dissimilar Organisms.t|—G. Klebs, starting with the principle that the life of every organism is necessarily bound up with the life of others, directs attention to some of the general conclusions derivable from a study of symbiosis. A great step in advance was made when P. J. van Beneden dis- tinguished commensalists and mutualists from true parasites, even though these divisions and their definition may require some amend- ment. When one organism lives in or on another, this relation may be due to one of two sets of causes; we have cases in which only one of the organisms is more or less compelled to be associated for some part of its life with another; here we have the proper relation of host and guest, or one-sided adaptation. In other cases it is necessary, that the two symbiosists should live together, and here we have mutual adaptation, though one may be more dependent on its fellow than the other on it. The author in what follows confines himself to the former set of cases, pointing out that the essential part of the relation is taken by the organism which seeks out the other, often larger, and often also more highly organized, for the purpose of fulfilling its own mode of life. Any one who has examined life in a pool or in the sea knows that almost every large organism, be it plant or animal, is covered with a number of smaller ones; this is the simplest case of symbiosis: smaller organisms make use of the surface of the larger one; thus alge will be found covered with diatoms; every tree on land is beset with alge, lichens, and mosses, and often there is a definite relation between them and the kind of tree on which they live. Various plants, * The Society are not to be considered responsible for the views of the authors of the papers referred to, nor for the manner in which those views may be expressed, the main object of this part of the Journal being to present a summary of the papers as actually published, so as to provide the Fellows with a guide to the additions made from time to time to the Library. Objections and corrections should therefore, for the most part, be addressed to the authors. (The Society are not intended to be denoted by the editorial ‘ we.” t Biol. Centralbl., ii. (1882) pp. 289-99. 602 SUMMARY OF CURRENT RESEARCHES RELATING TO especially algz, attach themselves to snails or mussels, and even to such actively moving forms as Cyclops or Daphnia. Numerous examples of animals are then cited; such as Vorticella, Hpistylis, Sponges, Hydroid Polyps, Bryozoa. In some cases (crabs and sponges) a rapacious host hides himself under the cover of his guest. Cases of higher symbiosis, in which the guest is not external, are next entered upon, and it is pointed out that, in addition to all these cases in which the host is always passive, there are others in which there is some kind of reaction between guest and host; thus the crustacean Cryptochirus coralliodytes affects the streams of water which pass to the- polyps of its coralline host; and corals are very frequently indeed affected in form by the crustacea or mollusca that give in them. In conclusion the author thinks that we gain but little information as to the cause of these symbiotic phenomena, if we are ~ content to say with Van Beneden that there is a “sympathy” between the host and guest. Electric Organs of Gymnotus.—G. Fritsch has two appendages to Sachs and du Bois Reymond’s great work * on this fish, in which he gives an account of his histological and morphological investigations into the nervous and electric apparatus; he finds support for the doctrine that the electric organs of Gymnotus have been developed from transversely striated muscle, a portion, the lowest lateral muscles, having been separated from the rest to form the so-called intermediate muscular layer, while a superior mass of muscle was converted into the great electric organ. The two are surrounded by a common fascia, which separates them from the so-called small organ which owes its origin to a metamorphosis of the muscles of the fin- rays. No explanation can yet be given of the remarkable variations (within 50 and 100) of the number of electrical columns. Hvery electric plate of Gymnotus arises from a certain number of primitive muscular bands which become connected together in their middle; the separate pieces of the compound plates do not, however, seem to correspond to a primitive bundle, but to a primitive cylinder (Cohn- heim) of the embryonic muscle. The mode of termination of the nerves may be most nearly compared with what is seen in the pseudo- electric organ of Raja; the spongy tissue around the nerve-endings and “thorny papille” is a supporting substance, directly continuous with the sheath of Schwann. In the description of the central nervous system attention is directed to the rounded form, well-developed cell-protoplasm, and broad attachment of the process of the axis-cylinder in the characters of the fully developed electric cell. B. INVERTEBRATA. Intracellular Digestion.|—H. Metschnikoff directs attention, in this connection, to the hydroid parasite found by Owsjannikoff in the ege of the sterlet; in the endodermal cells of that parasite were to be * «Unters. am Zitteraal’ (Sachs und du Bois Reymond) 446 pp. (8 pls.) 8vo, Leipzig, 1881. + Zool. Anzeig., v. (1882) pp. 310-6. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 6038 seen small highly refractive granules, which “ undoubtedly owed their origin to nutrient matters taken into the interior of the cell.” The author is of opinion that in the Turbellaria and Ccelenterata (inclusive of Sponges) intracellular digestion is the general rule; a very suitable form for its demonstration is stated to be young Ctenophores, for in them the whole process can be followed out to the end (i.e. till the time when crystalline concretions appear within the vacuoles) in one and the same individual. The opinion of Krukenberg that colouring matters are indigestible, is not supported by the author’s observa- tions, carmine, for example, being distinctly absorbed; and Hisig has lately shown that carmine is digested in the intestinal canal of the Capitellide and excreted by their segmental organs. Some other remarks of Krukenberg are closely criticized, and are regarded by Metschnikoff as not really affecting the reality of intracellular digestion in the lower forms. Mollusca. Nervous System of Mollusca.*—W. Vignal finds that the nerves are surrounded by a sheath of connective tissue of some thickness, which is formed of imbricated lamelle, containing a number of nuclei; in the terrestrial pulmonate Gasteropoda the true sheath is invested in a second, formed of a layer of vesicular cells, which is not however, proper to the nerves, as it is found also on the vessels. From the true sheath there are given off a number of partitions, made up of several lamellz, which pass towards the centre of the nerve; as they do so the lamellz divide afresh and unite one with another to form spaces of various sizes, in which we find the axial portion of the nervye-fibrils, and the protoplasm which surrounds them. While there are a number of nuclei in the partitions there are none in the proto- plasm: the sheath is not to be compared with the sheath of Schwann in the Vertebrata, but if it is to be compared with anything found in that phylum, it must be with the intrafascicular connective tissue. This peculiar structure of the envelope of the nerve-fibres is, it is remarked, found very generally among the Invertebrata, something analogous being found in both Hirudinea and Lumbricide. Its presence affords an explanation of the difficulty of dissecting out any length of nerve-fibrils. These fibrils themselves spread over the surface of the ganglia and penetrate some way into their interior; in this region the protoplasm contains a number of fatty and pigmented granulations, which would appear to form a reserve used up by the animal in the winter, as they are much more numerous (in Helix) during the summer than they are at the end of the period of hibernation. The author finds that for the demonstration of the partitions chloride of gold is the best reagent, for they are coloured by it while the nerve-fibres are almost unstained ; if the section is then decolorized by cyanide of potassium, and afterwards treated with picro-carminate of ammonia, the nuclei are very easily seen. The fibrils are best demonstrated by a mixture (in equal parts) of osmic and chromic * Comptes Rendus, xcy. (1882) pp. 249-51. 604 SUMMARY OF CURRENT RESEARCHES RELATING TO acids; after it has been used for the specimens hardened in alcohol, the sections may be coloured by hematoxylin, and afterwards decolorized by very dilute formic acid. North-American Cephalopods,*— Professor A. E. Verrill has published the second portion of his paper, in which he deals chiefly with smaller forms, though the commencement is occupied by an account of a young example of the gigantic Architeuthis harveyi. Observations on the habits of squids tell us that the fish captured are devoured with great rapidity, and it would seem that the jaws are the principal organ, while the odontophore plays only a subordinate part. The differences in anatomical structure between Loligo and Ommastrephes are carefully pointed out; in the latter there is not one large, but two small oviducts, and the nidamental glands are smaller and simpler; though, it is to be remembered, they were not examined in the breeding season. A new genus, Chiloteuthis, allied to Enoploteuthis, is formed for a creature with a very complicated armature; the sessile arms have sharp incurved claws, arranged in four rows on the ventral arms, and in two rows on the others; other characters are detailed and an account is given of C. rapaw n. sp. The family Desmoteuthide is formed for genera which have been confounded hitherto with the Crambide and Loligopside; Desmoteuthis n.g. has for its type Leachia hyperborea. The sexual differences in “oligo pealei are examined, and it is stated that the hectocotylized condition of the arm in the male is, contrary to the opinion of Steenstrup, developed in proportion to the development of the internal organs, and is not noticeable in the youngest males. Notes on the development and rate of growth follow. A new species of Rossia (R. megaptera), remarkable for the great size of the fins and eyes, and for the length of its tentacular arms, was taken off the southern coast of Newfoundland. It appears to be a species adapted for greater depths than its congeners. Another new family is that of the Alloposide, allied in some respects to Philonewis and Tremoctopus. The arms are extensively webbed; the mantle-edge, as in Desmoteuthis, is united directly to the head. In an appendix the author describes several other new forms, and enters into some critical remarks on the work of other naturalists. Marginella and the Pseudomarginellida. | —J. Carri¢re com- mences with a notice of the four zones found at the island of Goree, each of which has its own fauna, different to that of the other zones. In the deepest we find, among other molluscs, Marginella glabella. The statement of Adanson that Marginella is to be found in the upper zone is not exact, for the shells there found, and so called, belong to quite a different kind of mollusc. Tull lately the animals which * Trans. Connect. Acad. Sci., v. (1882) pp. 259-446 (28 pls.). + The first portion in tom. cit. pp. 177-257. { Zeitschr, f. wiss. Zool., xxxvii. (1882) pp. 99-120 (1 pl.). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 605 inhabit these shells have not been detected, and the resemblance between the shells of the upper and those of the lowermost zone are so close that no conchologist is to be blamed for associating them with one another. On closer examination, however, of the internal struc- ture, very important differences are to be detected, and the whole account is so instructive that we give a résumé of the author’s table of differences. The three forms may be distinguished as M. glabella, Pseudo- -margineila leptopus, and P. platypus. In all cases the shell is that of M. glabella, but while the foot of the form properly so called is broad, flat, and tapers posteriorly, being red in colour, that of P. leptopus is narrow and high, of the same breadth throughout, and colourless, save for black spots at the sides, and that of P. platypus is broad, flat, the same breadth throughout, and cu1ourless. So, again, the operculum is either absent, or is like that of Fusus (unguiculate), or is lamellar, as in Purpura. The tentacles of Marginella are long, the radula has only the middle plates, and these are broad and pro- vided with a number of small teeth, while the pedal gland is large in proportion to the foot. In both Pseudomarginellids the foot-gland is very small; in P. leptopus the tentacles are short and broad, while in P. platypus they are short and round. The lateral plates of the radula are, in the former, broader than the median plate, but in the latter they are unciform and much smaller. Indeed, P. leptopus appears to belong to the Buccinacea, while P. platypus is probably one of the Purpuracea. It is pointed out that, thanks to the investigations of Semper, we know that the very opposite of the conditions here described may in some cases be found to obtain ; that is to say, there are forms (Chlorea and Dorcasia) in which, though the animals are closely allied, the shells themselves are very different. The studies of later years show that shells with a large wide orifice are very variable; and now we find that Marginella is a form with a narrow orifice. The author insists on the important bearing which observations of this kind have on the determinations of paleontologists and the theories of stratigraphical geologists. Vascular System of Naiades and Mytilide.*—Dr. H. Griesbach gives a preliminary notice of his studies on this subject, which has always attracted much attention, in association with the taking of water into the body of these molluscs. The animals were placed in water coloured by green iodide; and the coloration was sooner or later noticeable in the foot, whence it extended into the most various regions of the body. ‘Uwing to the chemical changes which take place in Anodon, owing to the presence in its tissues of a large quantity of calcareous salts, the tissues will be found to be coloured violet. The author has been able to force injections through the slit-like orifice in the foot (one of which lies quite anteriorly, and the other two at about the middle). The colouring matter may be observed to pass not only into the larger trunks, but also, with care and patience, may be detected in the vessels of the muscles of the foot. * Biol. Centralbl., ii. (1882) pp, 305-9. Ser. 2.—Vot. IL. 2 606 SUMMARY OF CURRENT RESEARCHES RELATING TO The author promises to give further details, and to demonstrate how the openings are connected with the blood-passages. He regards the water that is taken as having a respiratory as well as an erectile function. Sexuality of the Oyster,*—M. Bouchon-Brandely points out that, while the common oyster (Ostreea edulis) is hermaphrodite, the Portu- guese form (O. angulata) is unisexual. In the latter the ova are expelled from the shell and fertilized in the water. The characters of their development are such as to yield no support to the doctrine of hybridization taught by some French ostreiculturists, and artificial fertilization of the two species has never yet been found to be success- ful. Artificial fecundation of O. angulata was, however, effected, and it was observed that the shell is formed on the sixth or seventh day after impregnation. The genital gland of this species does not have its elements matured until the time when it becomes transparent. Having been successful in small attempts at artificial fertilization, the author has successfully attempted some experiments on a much larger scale, Arthropoda. a. Insecta. Respiratory Movements of Insects. |—F. Plateau finds, as the chief results of his experiments, that— 1. There is no close connection between the character of the respiratory movements of an insect and its systematic position. ‘The respiratory movements are only analogous when there is very nearly the same structure of the abdominal rings, and of the muscles which move them. For example, the respiratory movements of the Phryganida do not resemble those in allied Neuroptera, but are much more similar to those of the aculeate Hymenoptera. 2. In all insects the diameter of the abdomen diminishes during expiration, owing to the approximation of the tergal and sternal pieces. The former, as in the Coleoptera, may alone be mobile, or the latter, as in Acridide, Libellulide, Lepidoptera, and Muscide; or the two may move equally, as in Tipulide, Sialis, and a few others. 3. The modifications in the vertical diameter may be accompanied by changes in the transverse diameter, as in the Libellulidz, Chrysopide, some Coleoptera, &c. 4, Contrary to what was formerly believed, it has been found that, during normal respiration, changes in the length of the abdomen are rare; they are to be seen in the aculeate Hymenoptera, and in such isolated cases as the Phryganida among the Neuroptera, and the Coccinellide among the Coleoptera. 5. In most cases the thoracic segments take no share in the respiratory movements when the animal is at rest, but they have been observed to do so in some genera of Coleoptera. 6. Contrary to the opinion of most observers, M. Plateau thinks that the respiratory wave is an exceptional phenomenon. It has not * Comptes Rendus, xev. (1882) pp. 256-9. + Bull, Acad, R. Sci. Belg., iii. (1882) pp. 727-37. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 607 been observed in any of the Coleoptera, the Acridida, Libellula, aculeate Hymenoptera, Muscide, and all Lepidoptera. 7. When there is a pause it is almost always during the inspiratory phases. 8. In large forms, suitable for such investigation, it has been observed that inspiration is ordinarily slower than expiration, and that the latter is often very rapid. 9. In most insects expiration only is an active movement, while inspiration is passive, and due to the elasticity of the integument, and of the walls of the trachee. 10. Inspiratory muscles are rare, but have been found in the Phryganide, as well as in the Hymenoptera and Acridide. 11. The so-called upper diaphragm, or ale cordis, as well as the lower, have not the function attributed to them by Wolff. 12. A large number of insects, perhaps all, impress on their abdomen general movements, which vary in intensity, but do not coincide with the respiratory movements proper. 13. These last are purely reflex, and persist after decapitation, and even (when the nervous system is not concentrated) when the abdomen itself is isolated. In it the movements may be hastened or retarded by just the same external causes as produce the same phenomena in the uninjured animal. 14. The metathoracic ganglia are not special respiratory centres, 15. The abolition of the respiratory movements, on the destruction of the metathoracic ganglia, which is to be seen in Dytiscus and some other Coleoptera, is due to the concentration of their nervous centres, some abdominal being fused with the thoracic ganglia. 16. In insects with a concentrated nervous system, the excitation or partial destruction of a complex nervous mass affects all the centres which enter into the composition of it. These important and interesting results are due partly to the use of the “ graphic method,” the movements being inscribed on a rotating blackened cylinder. In addition to this, a “method by projection” was used. An insect fixed by a slight support, and in such a way as not to affect its respiratory movements, is introduced into a large, well-illuminated magic lantern. The objects of the investigation— the respiratory movements—are then thrown upon a screen, whence they can be drawn on a sheet of paper. Displacements of a fraction of a millimetre can thus be followed. This latter method is a modification of that of Professor Valerius. Further details will be given in the complete memoir, of which this is only a preliminary notice. Location of Taste in Insects.*—J. Kiinckel and J. Gazagnaire have studied minutely the anatomy of the epipharynx (labrum of authors) and hypopharynx in the Diptera. They form two troughs, whose concavities are opposite each other, the hypopharynx being embraced by the margins of the epipharynx. In Volucella the walls * Comptes Rendus, xciii. (1881) pp. 347-50. 9 Te 608 SUMMARY OF CURRENT RESEARCHES RELATING TO of the latter become less rigid towards their margins, which are membranous. Just above them the internal face of the organ is beset with small modified hairs, arranged with regularity ; the anterior end is armed with six pairs of straplike organs, jointed at the base and minutely spined, some of which serve to sweep pollen from the corolle of flowers; the ventral pair carry 10 or 12 modified hairs in front of the joint. Passing by the arrangement of the muscles in the epipharynx, we come to its nerves. They are derived from the supra-cesophageal ganglia; about half-way along the epipharynx they approach the middle line and break up into a number of fibres which are connected with the modified hairs which occur on the extremity, other fibres having been already distributed to the hairs which fringe the margins of the epipharynx. At the base of these hairs (which are button-like and placed on pointed chitinous processes) the neurilemma forms small swellings, and the axis-cylinder ends in a fusiform cell provided with nucleus and nucleolus, whose distal extremity becomes attenuated and terminates at the base of the protuberance which surmounts the button. The hypopharynx has its membranous ventral wall reflected over the dorsal wall of the labium and covered with small hairs; its anterior extremity carries five spines. The space between its two walls opens towards the labium in front, and to the pharynx below ; at this point the salivary duct also opens, and the salivary secretion is thus liberated opposite to the very spot on the epipharynx above, on which the terminal nerve-endings are situated. By this arrange- ment the saliva, charged with digested matters, meets these nerve- endings and evokes in them a gustatory sensation from the matters which it holds in solution. Taking this in connection with facts previously determined, it seems reasonable to conclude that gustation in the Diptera commences with the paraglosse, at the point at which the false tracheze open, is continued along the false tracheze and becomes intensified at the extremity of the epipharynx, where quite a bouquet of nerve-endings occurs; it is prolonged along the margins of the epipharynx and operates at the entrance or throughout the cavity of the pharynx. Parthenogenesis in the Bee.*—G. Ulivi considers that partheno- genesis in the bee is a myth, the result of his observations being as follows :— 1. Queens are usually fertilized inside the hive. On their return from the so-called “ marriage-flight” they had empty spermathecas, while the act of fertilization was repeatedly witnessed in the hive. 2. They are fertilized several times. 3. Drones are not mutilated in the act of copulation. No lacerated drones were found after several careful examinations of all the drones in hives in which impregnation had taken place, and the whitish appendage attached to the queen’s abdomen on her return from the “ marriage flight ” was found to consist of excreta. * Amer. Natural., xvi. (1882) pp. 680-1, from the report of G. F. Kreeh in the ‘ Scientific American,’ 25th March, 1882. ‘ ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 609 4, Every egg that hatches into a male or female has been previously fecundated. Queens that had been allowed to fly were afterwards confined in hives containing no drones or drone brood, and either laid no eggs, or laid eggs that did not hatch. 5. Every queen whose spermatheca is distended and filled with liquid has been fertilized. 6. The eggs of a queen that has never met a drone will not hatch. 7. There is no such thing as a fertile worker. Fertile eggs will keep through the winter and hatch in the spring, and this hatching of fertilized eggs in queenless colonies has led to the belief in fertile workers, “The investigations,’ writes W. N. L.* “appear to have been carefully and thoroughly conducted, and every result is based upon repeated observations. Should they be confirmed, not only will the theory and practice of bee-keeping be revolutionized, but another example will be added to the many that go to prove how slow man- kind should be to accept as true, conclusions opposed to the ordinary laws of life. The continued reproduction of the aphides, sometimes called parthenogenesis or virgin maternity, is really of a very different nature. It isa process of budding differing from the budding of a zoophyte chiefly in the fact that it takes place upon an internal instead of upon an external surface.” Eye of Chloe diptera.t—In this Ephemerid, according to G. V. Ciaccio, the male, in addition to the compound eyes and ocelli of the female, has two large accessory compound eyes. He has discovered that these eyes “are distinguished in a marked manner from the ordinary ones, not so much by differences in their colour and form and the greater size of the crystalline cones, as by the fact that the optic rods do not consist each of a single piece but of two differently shaped and quite distinct portions, the one anterior, the other pos- terior.” The first has the form of a six-sided prism and is about the same size as the rods of the ordinary eyes; it consists of a whitish filament containing a coloured granular substance. The second is a single filament, endowed with a peculiar refractive power, and is a rolongation of the first. In order to reach their respective cones, all the filaments traverse together a substance composed of large granules of a dirty white colour, verging on yellow. In the stemmata, moreover, there is a large biconvex crystalline lens, placed just behind the cornea, which is curved, thin, and * tessellated behind with small cubical cells.” It also seems to Ciaccio worthy of careful consideration, as not hitherto noticed in other insects, that the lens is not chitinous, but consists of a peculiar, rather soft substance, fairly transparent, containing a reticulation of very delicate fibres, with round or oblong nuclei placed at the nodes of the network. ‘There is no capsule to the lens; its place is taken by a substance of the same character as that of the lens, but denser towards * Amer. Natural., xvi. (1882) pp. 680-1. + Rendic, Accad. Sci. Bologna, 1880-1. Cf. Bull, Soc. Entomol. Ital., x1. (1882) p. 154. 610 SUMMARY OF CURRENT RESEARCHES RELATING TO the periphery. The lens is kept in its place by a very delicate fibrillated tissue, perhaps representing the vitreous humour, inter- calated between the lens and the retina. The latter, like the simple eyes of the Diptera, is composed of rods and large fusiform cells, each of which is continuous with a fibre of the optic nerve. Marine Caddis-fly.*—Mr. R. M‘Lachlan describes and figures the larva of a caddis-fly (Philanisus plebejus Walker) which inhabits rock pools between high and low water marks in New Zealand, and forms its case of coralline sea-weed. No truly marine form has hitherto been recorded, though at least one species lives in the brackish water of the shores of the Baltic, and several are found in salt marshes or pools occasionally invaded by the sea. y. Arachnida. Respiratory Organs of Arachnids.j —J. Macleod, in a pre- liminary account of his observations on these organs, commences by stating that his earlier researches had led him to regard the lungs of Arachnids as a special form of trachea, or, in other words, as modified trachez, and in support of this it is pointed out that, while the tetrapneumonous Araneids have two, and the dipneumonous forms one pair of lungs, the latter have a pair of tracheal stigmata, comparable to the same organs in insects. _ The lungs may be regarded as consisting of a cavity or chamber, the hinder portion of which opens to the exterior by means of a trans- verse slit, the lips of which are pro- vided with a thickened chitinous pad ; the chitinous lining of the cavity is continuous, at the stigma, with the cuticle of the external integument. Into the cavity there extend the lung lamelle ; each of these is composed of two chitinous layers, the spaces be- tween which are occupied as blood- passages ; for all the passages there is a common vestibule (Fig. 109), and the slits of all are similar to one another, with one exception ; the last, instead of being cylindrical, is more or less tri- angular, its chitinous cuticle is thick and carries a large number of spines well developed, and so arranged as to form a kind of second tunic. With regard to the trachez in the Araneida, we see that they may be simple or branched, and their stigmata confluent or separated. In an Argyroneta, in which they are well developed, there are two large cylindrical primary trunks, which open to the exterior by two Fig. 109. * Journ. Linn. Soc. (Zool.) xvi. (1882) pp. 417-22 (5 figs.). + Bull. Acad. R. Sci. Belg., iii, (1882) pp. 779-92. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 611 slits confluent along the middle line, and which give off a number of ramifications; the wall of each primary trunk is composed of an external chitinogenous wall, and an internal chitinous layer, covered by a large number of spines which unite with one another as in the last tube of the lung. The author believes that the trachee of Argyroneta are nothing else than the last slit of the second lung of Mygale, enormously developed, while the rest of the organ is obliterated. A comparison between the lungs of Arachnids and the gills of Limulus is then entered upon, in which especial attention is directed to the work of Prof. Ray Lankester, which we have already noticed ; Fie. 110. Fig. 111. M. Macleod agrees in regarding the organs as homologues, but he thinks that their relations may be explained more simply than they Fie. 112. have been by the former. Let us begin by supposing that there is a considerable elongation of the abdomen of the Limulus, without any other change; the result of this modification would be that the respiratory limbs would no longer imbricate (Fig. 110). If, now, the sternal region should en- large and fuse for its whole length into the ventral, while the infero-superior axis were elongated, we should arrive at the abdomen of a scorpion, where each lung was replaced by a gill (Fig.111). Hach gill would be composed of a quad- rangular plate fixed by its intimal edge A B, and its anterior edge BC (Fig. 112a), and free on the other two; this plate would serve for the 612 SUMMARY OF CURRENT RESEARCHES RELATING TO insertion of a certain number of delicate quadrangular lamelle, only fixed along the edge By. If the animal passes to a terrestrial mode of life the flaccid lamelle, which were previously supported by the water, will apply themselves to one another, and will only be very imperfectly in contact with the air. They will become attached by their faces. [The three diagrammatic figures represent the modifica- tions which have probably been undergone by the gill of a Limulus in becoming converted into the lung of ascorpion. a Limulus, b an intermediate stage, c a scorpion, s# sternal plate, A BC D respiratory limb, attached by A B to the sternal plate, a @ y 6 respiratory lamella. The dotted lines indicate where fusion has taken place, the black ones the presence of a free chitinous edge af and yd to the wall of the depression in which they are placed. The chitinous plate (modified limb) which covers them will fuse by its external edge C D to the edges of this depressicn. | Limuli (Five pairs of branchiferous appendages) Passage to terrestrial mode of life. The first pair of respiratory limbs loses its function. The four following are adapted to aerial respiration. Scorpions (The two hinder lungs disappear) | | | Telyphonus. - The rings of the abdomen fuse. Tetrapneumones. The second pair of lungs converted into trachez. Dipneumones. In conclusion, doubt is thrown on the protracheate nature of Peripatus, and the suggestion is made that the respiratory organs of the Arachnida are not homologous with those of the Insecta. Habits of Scorpions.*—Professor E. Ray Lankester records some interesting observations which he has recently undertaken on Androc- tonus funestus and Huscorpius italicus. Of Androctonus he relates their mode of burrowing in sand, making horizontal tunnels which are often as much as 8 inches long. They commence by pushing the large chelee into the sand and seraping very rapidly backwards with the three anterior pairs of walking-legs, this use of the legs comparing with the parallel but not identical use of the legs in Limulus. They were evidently timid, hiding in the daytime. Their carriage is remarkable, as in walking they raise their body well from the ground, the tail reflected over the back, and the sting carried just over the cephalic shield ready to give * Journ. Linn. Soe. (Zool.) xvi. (1882) pp. 455-62 (8 figs.). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 613 a forward stroke, the large chele widely outstretched and held hori- zontally, the creature fecling its way with them. They only feed at dusk or at night. The prey is seized by the left chela, and at the same moment the sting is swiftly brought over their head and the victim pierced with it. The short chelicere are then inserted into the soft substance of the prey and the nutriment brought to the mouth by alternate movements of the right and left cheliceree. The combs or pectiniform appendages ordinarily do not appear to possess any special sensitiveness, but they may possibly become more so during the breeding season. The well-attested statement of the suicide of the scorpion when surrounded by a ring of red-hot embers, may perhaps be explained by the fact of some individuals accidentally lacerating themselves with their sting when half suffocated; Professor Lankester having seen a scorpion under the influence of chloroform vapour make repeated blows with its sting in the forward direction straight above its head until the top of the sting caught under the free projecting margin of the posterior region of the cephalic shield. The body of Euscorpius is kept close to the ground, the legs extended on either side, the tail being dragged behind with the slightest upward curvature only, or one to the right or left. In fighting one another the large chele were used but never the sting. In stinging their prey they do so with great deliberation, the slowness of the process being perhaps due to the fact that the poison-glands have to be compressed by their proper muscles, and the poison squeezed out of the lumen of the gland after the sting has pierced the prey. Nest-forms of the Furrow Spider.* — Dr. H. C. M‘Cook has observed that some of the orb-weaving spiders have a marked tendency to vary the forms of their nests. The spinning-work of spiders may be classified as (1) the snare, spun for the capture of prey; (2) the enswathment, by which insects are disarmed and prepared for food ; (3) the gossamer, used for purposes of aqueous or aerial locomotion ; ts} the cocoon, spun for the propagation and protection of the species ; and (5) the nest, which is a domicile more or less elaborate and per- manent, within or under which the araneid dwells for protection against enemies and weather-changes. As arule the great groups of orb-weavers differ from each other and agree within themselves in the characteristic form of nest. The form prevailing in each family is substantially the same; each species appears to adhere quite steadily to one characteristic form; but there are some marked vari- ations in the habit of certain species, the most decided of which have been observed in the case of Epeira strix, the furrow spider. He gives some examples of this. The ordinary nest when domiciled in the open field or wood is a rolled leaf. A second form varies from the rolled-leaf nest in having the edges of two adjacent leaves bent towards each other and lashed together on the exterior at the juncture by silken cords and on the interior by adhesive tissue web. An oval opening is left at the united * Proc. Acad. Nat. Sci. Philad., 1882, p. 97. 614 SUMMARY OF CURRENT RESEARCHES RELATING TO points of the leaves, through which the connecting-line passes to the snare. The spider domiciles within the leafy cavern thus formed. Again, the spider avails herself of small holes in wood or stone, openings in fences, the interspace between curled bark on the trunk of old trees, or some like cavity, which she appropriates as a nesting- place. Another variation was due to an accident in the environment of the web. A colony of carpenter ants dropped their chippings on the web until a ball as big as a walnut had accumulated, which was then utilized by the spider as a nest, the interior being bored and silk- lined. Other special variations are noted, including that of the nest attached to exposed parts of human habitations, such as the cornices of porches, outhouses, &c., and “it is thus seen that while there is a general regard to protection of the spider’s person, there is a modifica- tion over a quite wide degree of variation in the form of the- pro- tective nest; further, that this modification appears to be regulated, more or less, by the accidental environment of the domicile, and in such wise as to show no small degree of intelligence in adapting the ordinary spinning habit to various circumstances, and to econo- mizing labour and material.” Parthenogenesis in the House Spider.*—Mr. F. Maule Campbell details some interesting observations on a probable case of partheno- genesis in Tegenaria guyoni, one of the females of which, after a confinement of eleven months, twice moulted and afterwards laid eggs which were duly hatched. This shows either that she was impreg- nated previous to the casting of the two exuviz, in an early and therefore immature stage, or that parthenogenesis occurs in the Araneidea. Hitherto no instance of virgin production has been recorded in the true spiders, though Mégnin, Kramer, Haller and Michael have shown that the females of some Acarina couple with the males prior to their final moult, and that practically there are two stages of sexual maturity. Beck and others have also related cases of undoubted parthenogenesis in the Acari. Segmentation in the Mites.|—P. Kramer describes the segmen- tation of a minute mite, Alycus roseus. The dorsal aspect shows a very distinct segmental line between thorax and abdomen. ‘The abdomen shows nine distinct segments, which follow one another exactly as in Podura. The segmental grooves between the first three are broad, and present somewhat the appearance of double lines, of which the anterior cut off the preceding segment, and the posterior commence the succeeding one. The lateral margin of the abdomen shows distinctly the convexities and constrictions which correspond to the middles and boundaries of the segments. The setation throughout follows the segmental conditions. The hindermost segment bears the perfectly terminal anal aperture, half of which * Journ. Linn. Soc. Lond. (Zool.) xvi. (1882) pp. 536-9. + Arch. f. Naturg., xlviii. (1882) pp. 178-82 (figs.). Ann. and Mag. Nat. Hist., x. (1882) pp. 183-4. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 615 is seen in the dorsal view, while the other half is seen in the ventral. On the thorax there is a distinct pair of eyes, furnished with very convex lenses, just as in Rhyncholophus. It further bears several long setew, of which the pair situated between the eyes is distinctly fringed. This special pair of set on the thorax when seen under a low power, especially as it is placed near the black eye- spots, leads one to suppose that we have here a respiratory organ, similar to the stigma of the Oribatide; but a higher power shows distinctly that they are nothing but an ordinary capillary structure. On the thorax there are also three longitudinal lines, branched in a tree-like fashion behind, and two transverse lines; and these divide its whole dorsal surface into several areas, three of which occupy the entire central space. On the lower surface the thoracic segmental lines are seen dis- tinctly running between the coxal plates of the second and third pairs of legs. The segmental lines of the back also pass on to the - lower surface bending forward in the middle of the abdomen. The segmental lines of the more anteriorly situated abdominal segments could not be distinctly traced on the lower surface. 5. Crustacea. Perception of Colour by Crustacea.*—C. De Merejkowsky fol- lowing Sir John Lubbock’s investigations into the perception of colour by the lower animals, has experimented on Crustacea, especially larve of Cirripedes and a Copepod. In darkness, the animals disperse to all sides of the vessel in which they are kept; if day- light is admitted through a slit, they congregate near the slit, and behave similarly towards monochromatic light, of whatever colour. Using two slits at an angle of 40° with each other and admitting white light by one and a monochromatic light by another, he finds that most, if not all, prefer the white light, but pale colours (yellow, green, pale red) also attract a few individuals. When two monochromatic lights are used, the brighter is preferred; with two rays of equal brightness the animals are equally divided between the two. Any superiority in the amount of light admitted attracts the bulk of the colony, whether the light is monochromatic or not. Thus it is seen that these animals appreciate only the quantity of the light, or the intensity of the vibrations which produce it, and are only sensitive to colour as implying a certain amount of light. Mediterranean Crustacea.j—L. Joliet describes a parasitic Crus- tacean which he found under the form of small, ovoid, reddish bodies in the general cavity of the Aleyonarian Paralcyonium elegans. Not at all unlike a tardigrade at first sight, their two pairs of antennz and the form of the hinder end of their bodies showed that they could be nothing else than crustaceans. The author soon found that the creature under examination belonged to the genus Lamippe, of which * Comptes Rendus, xciii. (1881) pp. 160-1. t Arch. Zool. Expér. et Gén., x. (1882) pp. 101-20 (1 pl.). 616 SUMMARY OF CURRENT RESEARCHES RELATING TO only two species have yet been described; one was (1858) found by Bruzelius in Pennatula rubra, the other by Claparéde in Lobularia digitata. The species now studied was found to change its form incessantly during life, so that at one time it was cylindrical, and at another rounded, and it might just as well as Claparéde’s species have received the specific name of proteus ; a kind of soft parenchyma, charged with globules, which are probably fatty in nature and are coloured red, fills the body and renders it almost opaque. The delicate chitinous membrane which envelopes the body presents no trace of permanent annulation, but only temporary constrictions, which correspond to any given state of contraction of the body. Of the details of structure we can only say that, so far as the nervous system is concerned, all that the author could discover was a small refractive thickening near the eye, to which he is in doubt whether or not he should apply the term of ganglion; the eye, itself, is unpaired though double, and is to be found on the dorsal side a little behind the rostrum. The nauplius-form was detected and some of its characters were made out. This third species has been named Lamippe duthiersii. As to its exact systematic position there would seem to be some not inconsiderable doubt, but it certainly is Crustacean, and, owing to the polymorphism exhibited by the parasitic Copepoda, we may for the present regard the Lamippide as forming a special division of that group. The next subject discussed by Joliet is that of the functions of the dorgal feet in the Notoproctous Crustacea. It is a well-known fact that the Dromi, especially when young, hide themselves under a kind of carapace, formed by a sponge or an aleyonium which they hold on their back by the aid of their hinder feet, and he has observed and here enters into full details with regard to the habits of these Crustaceans ; he finds also that the Dorippide do the same thing, and, though there issome difference in the anatomical structure of these two sets of forms, there is no doubt that they have the same habit of hiding themselves under various objects either to protect themselves against their enemies, or to hide themselves from their rey. - Pontonia diazona n. sp., presents an instance of mimicry. The Ascidian genus Diazona is very common at Mentone; having placed a small quantity of the masses formed by these creatures in clean water, the author was, shortly afterwards, surprised to see a small Crustacean swimming freely about. From a distance the animal could only be detected by the movements that it made in the water, so com- pletely transparent was it. Left to itself, it soon re-established itself on the Diazona, where the transparent parts became so completely confounded with the hyaline structures of the Ascidian, and the yellow parts agreed so completely with the yellow markings of the colony, that it was only by shaking or by previous knowledge that its exist- ence could be detected. It was not possible to discover whether it was a true parasite, or only a commensal, but its coloration and its habits are sufficiently striking examples of mimetic action to justify ‘ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 617 attention being drawn to it. A technical account is given of the specific characters, but the author was unfortunately unable to draw the creature while it was fresh; the characteristic coloration dis- ' disappears after preservation in alcohol. North American Crustacea.*—S. I. Smith has some notes on the zoea-forms of Pinnixa, distinguishing a long-spined and a short- spined series, and he describes the characters of the adult P. chetop- terana, and P. sayana. He directs attention to the occasional occurrence of tropical and sub-tropical species of Decapod Crustacea on the coast of New England, and summarizes the information that has been collected regarding these forms. In giving an account of some genera of Amphipods, he says that in several forms the excrement enters largely into the formation of the tube. A species that was placed in a small trough with alge pulled towards each other a few slender branches of the alga; these were fastened by threads of “cement spun from branch to branch by the first and second pairs of pereeopods.” When the tube had nearly attained its complete form it was still usually nothing but a trans- parent network of cement threads.with here and there a small piece of alga. Soon after this the animal began to work into it pellets . of excrement and bits of alga; the former seized by the more anterior appendages were broken into minute fragments and worked through the web. This went on till the whole animal was protected from view; the process of construction would seem to take about halfanhour. All the tubes are black externally, thin, and cylindrical ; within they are lined by the cement; they do not seem eyer to be attached, but to be carried about by the animal. New Copepoda.j—S. A. Forbes records new genera and new species of Copepoda from Lake Michigan and pools in Illinois. Osphranticum noy. gen. is similar to Diaptomus in general appear- ance, but differs especially in the structure of the fifth pair of legs of male and female. O. labronectum is the single species. Epischura nov. gen., in the general character of the legs both natatory and clasping, stands near Heterocope of Sars, but is remarkably dis- tinguished from all other Copepoda by the development of the abdomen of the male as a prehensile organ, the second and third of the five segments are produced on the right side as large and strong processes which act against each other like forceps, while a toothed plate on the fourth segment and a spatulate one on the fifth assist to form a peculiar and powerful grasping apparatus. “A steel trap attachment to the tail of an alligator would,” the author says, “ very well illustrate the vigorous embrace of the animal” (EH. lacustris noy. sp.). In addition, three new species of Diaptomus (D. sicilis, D. leptopus, and D. stagnalis), and two new species of Cyclops (C. thomasi and C. insectus) are described. In ten “bladders” of Utricularia vulgaris, taken at random, 93 animals, either entire or in recognizable fragments, were found, repre- * Trans. Conn. Acad., iv. (1882) pp. 243-84 (1 pl). + Amer. Natural., xvi. (1882) pp. 537-42, 640-9 (2 pls.). 618 SUMMARY OF CURRENT RESEARCHES RELATING TO senting at least 28 species. Seventy-six were Entomostraca of 20 species. Nearly three-fourths were Cladocera. One-third were Acroperus leucocephalus Koch. Vermes. Development of Annelids.*— Professor W. Salensky gives an account of his own observations; in dealing with marine forms, he studied among others a species of Terebella, Nereis cultrifera, and Spio fuliginosus. In all that he studied he found cleavage to be unequal, and to lead to the formation of an amphi- gastrula; before the division on the surface of the egg lively proto- plasmic movements were always observed in Spio, the protoplasm giving rise to lobate, clear, pseudopodia-like processes, which altered in form during the whole process of division, and at its conclusion were withdrawn. The first rudiment of the mesoblast appeared to arise from the micromeres of the second cleavage ; in some other cases the mesoderm appeared in the form of two primitive mesoblasts lying near the edge of the blastopore; in Psygmobranchus the primitive endodermal cells do not represent the whole endoderm, for they only form the dorsal portion of the nutrient cavity, while its ventral wall arises from a collection of cells on the ventral surface (secondary endoderm). The author finds that the mode of formation of the mid-gut is different in the forms examined by him; in Nereis dumerilii Goette found that the endoderm arose from the four large endodermal cells, in the form of a ventral cord of cells, while the four (and later) five large fat-containing cells were pressed forward and dorsally, and used as nutrient yolk. In this arrangement the author found Psygmobranchus to agree more closely than N. cultrifera. Differences were observed in the origin of the fore- and hind-guts, which in Psygmobranchus and Aricia had an endodermal, and in Nereis an ectodermal origin. Striking as this difference would appear to be, it was found to be really more quantitative than qualitative; and the endodermal origin is to be regarded as nothing more than the result of an incomplete ectodermal invagination. Greater similarities were noted in the mode of development of the nervous system; and the results of Kleinenberg and other later investigators as to the independent origin of the supra-cesophageal ganglion and the ventral ganglionic chain were confirmed. It was noted that a cord-like process always extended from the lower surface of the frontal plate to the subjacent mesoderm; and these were regarded as being homologous with the cords which, in vermian larve provided with mesenchymatous cells, form the rudiments of these cells. After discussing the characters of the ventral ciliated groove, Salensky states that in not very young larve of Psygmo- branchus he observed, between the epithelium of hind-gut and the “ Darmfaserblatt,’ a cavity filled with clear fluid; the wall of the cavity was contractile and exhibited regular pulsations, by means of which the fluid was driven forwards. In Terebella, likewise, the formation of the blood-vessels is preceded by such a perigastric * Biol. Centralbl., ii. (1882) pp. 198-208. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 619 cavity, whence the enteric vessels are derived. It is important to note that in the lower Annelids (e. g. Protodrilus leuckarti) there is permanently some such arrangement of the blood-vascular system, while, further, we are shown that at first the blood-vessels have nothing to do with, but are completely independent of, the lymphatic spaces (ccelom, &c.). In Branchiobdella the ova, like their parent, are to be found in the gill-lamelle of the crayfish; they are of some size and are covered by a hard shell, produced posteriorly into a small stalk of attachment. There is very early a difference between the appear- ance of the dorsal and ventral surface, and cleavage obtains much more rapidly among the cells of the latter. The endoderm and mesoderm are formed by the division of the macromeres, which constantly extends from behind forwards; no primitive mesoblasts were detected. Soon after the. formation of the layers a small depression appears on the dorsal surface, the significance of which could not be made out, though it was possibly the rudiment of the supra-cesophageal ganglion. Soon after the appearance of this de- pression there appears on the ventral surface a large groove—the neural groove; this is pyriform in shape, the broader end being posterior, and the narrower anterior end having a T-shaped enlarge- ment. At first, the groove consists of a layer of flattened cells, which are not to be distinguished from the other ectodermal cells; they soon, however, increase in number, and the groove itself is thereby narrowed and flattened out, till it becomes converted into a tube—the neural tube. About this time, the hinder portion of the embryo also becomes altered; the cells which were arranged in two rows divide, and the hinder part gives rise to two median ridges, which correspond to the germ-stripes of other Hirudinea. Segmenta- tion commences early, and, after it has commenced, the embryo undergoes a series of changes, in consequence of which the dorsal surface ceases to be, and the ventral becomes convex. Prior to the formation, which is somewhat late, of the ccelom there is a cavity on the dorsal surface between the ecto- and endoderm ; this is generally anterior in position, and may be spoken of as the primary ccelom. The oral invagination of the ectoderm gives rise to nothing but the inner lining of the lips, all the other parts of the mouth and its region being endodermal in origin. Development of the Central Nervous System of Annelids.*—It is pointed out by J. W. Spengel, in an account of Kleinenberg’s recent researches on this subject, that we have here to do with the development of new structures in the course of phylogenetic develop- ment. The special larva studied appears to have been Lopadorhynchus, which is of the Lovenian type. Simple as are most of the organs of this form, the ectoderm presents considerable histological differentia- tion ; a strong nerve lies in the groove formed on the ciliated girdle, and this nerve is circular. On the upper hemisphere of the larva the ectoderm is found to consist of large elements, immediately below * Biol. Centralbl,, ii. (1882) pp. 231-6. 620 SUMMARY OF CURRENT RESEARCHES RELATING TO which we find a small but deep pit in the ventral middle line. The cells around the pit are small and spindle-shaped, or are large and branched, and call to mind isolated ganglion-cells. The latter do not touch the surface, but are completely shut off from it by other ecto- dermal cells. Allthese form the first rudiment of the preoral nervous apparatus of the larva. On the lower hemisphere of the larva part of the ectoderm is, again, composed of as large cells as some of those in the upper hemisphere, and these are found in a ventral triangular area, the apex of which is turned towards the anus. This area is divided by a groove into two symmetrical lateral halves. On either side there is a thickened ectodermal band, the so-called ventral germ-band. From this there is gradually separated off a lower layer which forms the definitive mesoderm, while of the remainder the median portion gives rise to the ventral nerve-cords. Before these series of differentiations have been completed the ganglion-cells of the upper hemisphere have, by means of their processes, become connected with one another, and have thus given rise to a kind of plexus. Some, however, of the small spindle-shaped cells have by their processes become closely fused with the fibres of the nerve-ring, and a transverse commissure has been developed by the anastomoses of the cells on either side of the hemi- sphere. We have now, therefore, got a semicircular loop which extends over the ventral surface of the upper hemisphere, and passes by its ends into the nerve-ring. Just about this time a connection is also established between the nerve-cords in the lower hemisphere and the circular nerves. As this takes place at the point of formation of the anterior commissure, we find that the rudiments of the cephalic ganglion and of the ventral ganglionic chain are at first con- nected with one another by the intermediation of the circular nerves. Kleinenberg compares this nerve-ring in the polychetous larve with the nerve-ring of the meduse, and speaks of the upper hemi- sphere of the worm-larva as the umbrella, and the lower as the sub- umbrella. But if the nerve-ring is the nervous system of the larva, then it has no homologue in the developed worm. ‘“ We see, therefore, in the cycle of the ontogenetic development of one animal an organ of the same physiological significance appearing twice over, and as being formed on two different types. The larve of Annelids possess the old nervous system of the Ccelenterata, while the Annelids themselves have their own proper central organs, which are in no way modifica- tions of the other. The organ of the lower type is developed, and is functional in the larva, but in the adult it is replaced by a fresh formation.” In explanation of this remarkable modification, Kleinenberg points out that variations have a definite character, which, though dependent on external activities, must also be conditioned by the characters of the form itself. The mere development of any new organ must be accompanied by changes within, though perhaps not without, the organism. There is a limit, as it were, of equilibrium to variations, but this limit may be passed if the change is of advantage, and then we find considerable modifications in the organism itself. The ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 621 development of a nervous organ must result in a rearrangement of all the organs of the body, and may affect indifferent tissues. When this happens new structures arise, which will owe the direction they take to the organ that has caused them, which probably will itself become larger and more complete. The formation of a central nervous organ will cause a change not only in the already developed peripheral nervous system, but in a number of indifferent ectodermal cells, which will take on a nervous character and become united into new organs. This process may be called that of substitution, and is not to be con- founded with change of function, or with the process of the physiological division of labour. Applying these considerations to the Annelids, and starting from the Ccelenterata, we find in the Annelid larva a nerve-ring and a sensory epithelium. The organs of the latter gradually took on the functions of the old nerve-ring, and became converted into more inde- pendent organs. As the function of the primitive central organ disappeared it became suppressed, and is only seen now in the organi- zation of the larva. The notochord and vertebral column of the vertebrata probably afford another example of this process of substitution. Coral-reef Annelid.*—The Rev. T. Powell gives an account of the structure and habits of Palolo viridis, in which he states his reasons for considering as inaccurate the notion that the animals break up into small pieces in order to effect the liberation of the egos and of the sperm. Their sight is evidently perfect. The time of their appear- ance is the day of the last quarter of the moon in each October, unless that fall at the beginning of the month, in which case another lunar month will intervene. This indicates that the moon exercises some mysterious influence on their reproduction. Muscular Tissue of the Leech.t—T. W. Shore finds that—1. The muscle of the leech consists of elongated tubes with two coats—a sarcolemma and contractile layer—the inner surface of which is irre- gular, and gives rise to apparently granular contents. 2. In the living condition it is unstriped. 3. There are no nuclei. 4. Trans- verse striation may be produced post-mortem, the result of three changes :—a. Regular arrangement of the papillz on the inner surface of the contractile layer. 8. Folding of the surface of the sarcolemma. 8. Splitting into segments of the contractile substances which subse- quently contract. 5. The contractile substance coagulates, forming myosin, which subsequently contracts. 6. The rapidity of contraction gives rise to varying appearances of fissures, striations, &e. Observations on the Dicyemide.t —E. van Beneden gives us the result of some further studies on these important forms. He commences by describing two new generic types, the first of which, Conocyema polymorpha, lives with Dicyema typus in the renal cavity of Sepia officinalis. It is not, however, nearly so common as its com- * Journ. Linn, Soe. (Zool.) xvi. (1882) pp. 393-6. + ‘Nature,’ xxvi. (1882) pp. 493-4. t Arch. de Biol., iii. (1882) pp. 195-228 (2 pls.). Ser. 2.—Vot. II. 2U 622 SUMMARY OF CURRENT RESEARCHES RELATING TO panion, but here, as elsewhere, two kinds of females can be distin- suished—the nematogenous and the rhombogenous. The former have _ a body of very variable external appearance; it may be elongated, irregularly rounded, claviform, much swollen at one extremity, or attenuated at both. Four granular lobes can always be distinguished, and these, although they vary much in form in different individuals, are always formed of a single cell, just as are the two lobes in Dicyema. Asin other Dicyemide, there is a cortical layer and an axial or medullary body. The former is made up of a small number of epithelial cells, set in a single layer, and so touching one another as to form a continuous membrane, which completely shuts in the medullary portion. Hach cell is ciliated in youth, and smooth when adult. It is not possible, as in Dicyema, to distinguish polar and parapolar cells, there being no cephalic tuft. As may be supposed, the medullary body consists of a single cell. In this there are to be found germs and embryos at every stage in development. It varies greatly in form, but is always limited by a firm layer of protoplasm, of equal thickness throughout its whole extent, and always capable of allowing of the passage of the contained embryos. The nucleus is ~ generally oval, has a distinct limiting membrane, and is traversed by a nucleoplasmatic reticulum. When the embryo is on the point of leaving its parent it presents a convex and almost hemispherical hinder face. It is about one and a half times as long as it is wide, and a short way from the anterior end there is a circular constriction which has sometimes the appearance of a rather deep groove. It is covered by vibratile cilia, by the aid of which it swims freely in the liquid of the corpus spongiosum, when it has made its way out of its parent, and in thus moving it describes a spiral. The cuneiform embryo of Conocyema, like the vermiform one of Dicyema, has a large central cell, and a peripheral epithelial invest- ment; but while in the latter it is always fusiform or cylindrical, it is here always spherical. Among the outer cells the four apical ones may always be distinguished. The embryos, with these characters, are all developed from monocellular germs, which have all the signs of true ovules. These divide into two, and then into four blastomeres, one of which is often very much larger than the rest. In the next stage there are six small and one large cell, and then we have an epibolic gastrula. The six smaller outer cells dividing, we get thir- teen in all, which is the number characteristic of the adult. The cuneiform embryo escapes to the exterior by perforating the body of its mother, the four apical cells become charged with granules, the axial cell becomes enormously developed, and new germs appear. After pointing out briefly the characters of the rhombogenous form, Professor van Beneden passes to Microcyema vespa, the small embryo of which was taken by G. Wagener for the infusoriform embryo of Dicyema gracile. It is divided into two parts by a median constric- tion ; the hinder of these consists of an axial fusiform cell, and of two others which completely envelope it. The anterior end of the central cell projects into the anterior segment, where there is also a granular mass and a cortical layer, formed of two clear cells similar to those ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 623 which are found in the hinder segment. The parent is tubular in form, slightly enlarged at one end, completely smooth, with a delicate cortical layer. Transitional forms between these two stages were observed, and it was found that the anterior tuft of cilia on the embryo disappears very early. The author thinks himself justified in regarding this form as a distinct generic type. As has been pointed out by Huxley, we cannot form any definite opinion as to the affinities of these forms until we know something more about the characters of the infusoriform embryo; Van Beneden believed that this form might be the means by which the parasite passed from one to another individual Cephalopod, but the researches of Metschnikof and Julin on the history of the Orthonectida have largely destroyed that hypothesis, and now give rise to the question whether the infusoriform type is not the mature male, and its “ urne”’ a testicle ; to see if this view could be confirmed the author closely examined them in the hope of detecting spermatozoa, but in vain. On the other hand, we now know that the spermatozoa of the Orthonectida are very small and very difficult to see. Too much weight must not, therefore, be given to this negative result. And the hypothesis which suggested the investigation commends itself, on many considerations, to the author’s mind. When the first studies on the Dicyemide were published, the absence of any mesoderm was insisted on ; since that time, and chiefly, thanks to the researches of the brothers Hertwig, it has been allowed that the mesodermal formations in the Metazoa have not all the same anatomical value. Still, it remains true that the Dicyemide have neither mesenchyma nor celomic folds. This being so, we find in this important fact a justification for the establishment of a phylum of Mesozoa. These may be defined as “organisms formed of two layers, the ectoderm of a layer of more or less ciliated cells, the endo- derm of a single or of several cells. The sexual products arise from the endoderm. There is no mesenchyma, ccelomic folds, or any funda- mental lamella; two female forms, one arising exclusively from the males, the other from the females. All the Mesozoa actually known are parasites.” They are divisible into the Orthonectida and the Rhom- bozoa; the former have the body composed of several rings and the endoderm of several cells, some of which take on the epithelio-muscular type, and give rise to muscular fibrils, while the others form the sexual products. The male is elongated, and the female oviparous. The Rhombozoa, which are divisible into the Dicyemida and Heterocyemida, have the body annelated, the endoderm formed of a single cell, no muscular fibrils. The male is peg-top in shape, refractive bodies are found in some of the smooth anterior cells, and the females are viviparous. The author discusses the question as to whether the Mesozoa are Metazoa degenerated by parasitism, and specially the doctrine of Leuckart,* that they are comparable to the ciliated larve of the Distomata. He points out that the resemblance is chiefly external, and that a Dicyema is much more like a Planula or a Gastrula, and * See this Journal, ante p. 343. ye 624 SUMMARY OF CURRENT RESEARCHES RELATING TO that, further, the ectoderm never gives any indication of the develop- ment of an intermediate layer. In examining the question of the homology of the medullary body of Rhopalura or Dicyema with the endoderm of a Metazoon, it is shown that in their earlier stages of de- velopment all the forms agree closely with one another, and if we allow that the inner layer (endoderm) is homologous throughout the whole of the Metazoic series, we can find no good reason for shutting out the endoderm of the Mesozoa. Certainly no supporting fact is to be found in the absence of a digestive cavity, as the Accela, among the Rhabdoccela, with their intracellular mode of digestion, are alone sufficient to demonstrate. Orthonectida.*—C. Julin here gives a full account of his re- searches, to the preliminary notice of which we have already referred (p. 511); he is of opinion that the Orthonectida cannot be considered as triploblastic forms or Metazoa, but as Mesozoa or diploblastic forms, the muscular layer which is developed not being a formation of a mesoderm, but only a histological differentiation of the endo- dermic cell; so far they resemble the Actinozoa, but they are dis- tinguished from them by the fact that the muscular cells do not, throughout the whole of their life, remain connected with the endo- derm. When we compare them with the Dicyemide we find various points of resemblance, (1) Just as in them there are nematogenous and rhombogenous forms, so in these there is a flattened form which gives rise only to female embryos, and a cylindrical form whence develope the males, and the two female forms are to be found in the same host; (2) the gastrula in both groups is formed by epiboly ; (3) the structure is essentially the same in the two—a ciliated ecto- derm, differentiated into a cephalic region at the anterior pole, and an endoderm of one or of several cells; the difference in this last character is due to the different mode of formation of the germs; in the Orthonectida they arise by division of the primitive endodermic cell, and in the Dicyemida by an endogenous process. The views of Giard and Metschnikof that the Orthonectida may be compared to the Turbellaria, are objected to chiefly on the ground of the great development of the mesenchyma in these lowly worms; the doctrine that they have degenerated under the influence of the parasitic habit is not confirmed by the history of their development, in which they exhibit no traces of any higher organization. Julin regards the Mesozoa as pluricellular organisms, composed of two kind of cells, ectodermal and endodermal, without any trace of any mesenchyma, ccelom, vessels, muscles or nervous tissue of meso- dermic origin ; they are developed by the division of the egg-cell and its differentiation into a peripheral and a central layer. He insists on the incorrectness of the use of the term metamere or segment as applied to these forms, pointing out that the appearance which has induced some authors to apply these expressions is due only to the presence at certain points of shallow grooves between the transverse rows of ectodermic cells, there is no internal segmentation corre- * Arch. de Biol., iii. (1882) pp. 1-54 (3 pls.). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 625 sponding to this appearance, and in some cases a large number of females may be seen to be without it altogether. A more proper term would be “ring ” simply. It is not easy to detect when an Ophiurid is infested by these parasites, but as a rule such specimens have a more greyish tint, their tissues appear softer, and their movements are less rapid; as a rule one in twenty Amphiure were found to contain Orthonectids; the observation of Metschnikof that a consequence of their presence is an atrophy of the genital glands, has been verified by Julin. An adult male is 0:104 mm. long, the body fusiform and elongated, and a little drawn out at either end, there are generally six rings, the cilia on the first (head) are directed forwards, and on the rest back- wards ; the spermatozoids are contained in a structureless pouch, and when mature may be seen moving about rapidly within it; when the wall of the pouch bursts they escape between the muscular fibrils, which separate from one another so as to form a cavity, bounded externally by the ectoderm; the cells of this layer undergo. change and some become detached, and the male products are then able to make their way to the exterior; at the same time it may be seen that the muscular fibrils undergo atrophy. The cylindrical form of the female is 0:280 mm. long, is fusiform and has generally eight rings, the first and last of which are formed by a large number of small ectodermic cells. The flattened form of female is 0° 250 mm. long, has wide ventral and dorsal surfaces, and narrower sides, the grooves are so shallow that it is impossible to count the number of the rings, and the whole surface is covered with cilia; this form was regarded by Metschnikof as being immature, but the presence of ova is not in support of that view, which is more com- pletely contradicted by the differences between its history and that of the cylindrical form; the flattened forms appear to break up into fragments, and the ova, instead of being free, are kept united together to form more or less regular masses, limited externally by a ciliated epithelial layer derived from the ectoderm of the adult. As has been already stated, there is a difference of sex in the products of these two female forms. As to the question of parthenogenesis, which is raised by some observations, the author does not yet feel himself able to speak confidently. New Rotifer (Cupelopagis bucinedax),*—Mr. S. A. Forbes de- seribes a new Rotifer as follows :— Cupelopagis gen. nov. Footless, eyeless, without carapace, and totally destitute of cilia or other vibratile structures, or locomotor organs of any kind. The trochal disk has the form of a large, oblique cup, which can be either retracted wholly, or pushed up by a constriction of its wide mouth. In the bottom of this cup is the oral aperture, which opens into a very large, loose crop, at the bottom of which, and usually behind the middle of the body, is the mastax. The jaws, which project into the crop, are composed of two sharp, slender hooks, with about four slender, straight teeth at the inner base. * Amer. Mon, Mier. Journ., iii. (1882) pp. 102-3 (1 fig.). 626 SUMMARY OF CURRENT RESEARCHES RELATING TO The stomach is large, and the intestine very small and short, opening on the ventral surface of the body near the posterior end. C. bucinedax sp. nov. The body is a coriaceous, flattened sac, minutely roughened over the whole surface, nearly as broad as long, and about three-fourths as thick. The dorsal outline is longest and strongly convex, the ventral being usually somewhat concave. The cup is oblique, the ventral height being a little more than half the dorsal. Its lower wall usually presents a shallow, longitudinal cavity, so that the aperture is slightly kidney-shaped. The surface of the cup is more delicately roughened than the body, and its edge is minutely erose. In the average specimen the length of the body, without the cup, was 0:016 inch, and its width 0-014 inch. This rotifer has no means of attracting its prey or bringing it within reach, but depends wholly on such animals as chance to swim into its oral cup. When a Stentor or other animalcule of considerable size enters the trap, the rotifer quickly pushes up the aperture and con- tracts the walls of the cup upon it, until it is forced, with a sudden slip, into the ample cavity of the pharynx. This apparatus enables it to secure much larger prey than the usual ciliated structure; but, in the absence of locomotor organs, it can only live in water swarming with suitable food. In the aquarium in which it was found it was living almost wholly on the large Stentors. The author adds* as the result of a communication from Dr. J. Leidy, that Dictyophora vorax described by him,+ is evidently closely allied and probably belongs to the same genus. The name is, how- ever, preoccupied. Echinodermata. Anatomy of Echinoids.{—R. Koehler finds that the Polian vesicle of regular Echinoids has the structure of an excretory organ; he describes them as being, to the naked eye, of a light brown colour, which is due to the presence of small brown lines which pass from the middle line to the periphery of the organ, becoming wider as they do so. The two layers of connective tissue, which form the walls of the organ, are so united that the space between them consists of small cavities, filled with special elements; these last are cells with a very distinct nucleus, and their protoplasm gives off fine prolongations, which extend from one cell to another. In addition, there are numerous granulations, arranged in masses and cubical cells, the nature of which could not be made out. On the whole, there is much resemblance to the excretory organ of Spatangus. The author describes the pedicellarie of Dorocidaris papillata, and directs especial attention to the presence of the small gemmiform ones on the buccal membrane, where they have never yet been recorded. “Five very curious appendages” are described in con- nection with the lantern of Aristotle, which are no doubt the gill- * Amer. Mon. Micr. Journ., iii. (1882) p. 151. + Proc. Acad, Nat. Sci. Philad., ix. p. 204. + Comptes Rendus, xciy. (1882) pp. 1260-2. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 627 like organs of C. Stewart. Of the four kinds of pedicellariz in Schizaster canaliferus one is tetradactyle ; in this form there are only two pairs of genital glands, and the sand canal does not follow its usual complicated course. In Brissopsis lyrifera the author notes a narrow canal which he looks upon as being a second “siphon,” and, in conclusion, he states that while his observations have led him to see only slight modifications in the details of the anatomical structure and arrangements of the internal organs of regular Echinoids, he finds that in the irregular forms the internal organs have, in their differentiation, followed the migrations of the branches, which com- menced in the Jurassic period and appear to have profoundly affected their primitive structure. Anatomy of Spatangus purpureus.*—R. Koehler has studied the circulatory system of this Echinoid. He finds that the branch de- scribed by Hoffmann, connecting the intestinal vessel with the perioral ring, bifurcates at the level of the mouth, and sends one branch to the blood-vascular ring and the other to the ambulacral ring. The sand-canal is double between the mouth and the end of the cesophagus; it remains single from this point up to the second curvature of the alimentary canal, and after this is divided by septa into several secondary chambers, up to the point where it opens into the “heart”; on the opposite side of that organ it becomes a narrow tube. The so-called heart is spongy, and its cavity is in direct con- nection with that of the sand-canal; it consists of connective tissue, provided with numerous nuclei and cellular elements resembling those of the blood; the membrane which attaches the sand-canal to the madreporic tubercle has a similar structure, and perhaps both organs are glandular, and discharge either excretory or blood-vascular functions. The blood-vessels of the alimentary canal are derived from the external and internal marginal trunks, but the cesophagus, the 3rd curvature, and the rectum, are quite devoid of vessels. Most of those on the 2nd curvature occur on its dorsal surface, the only ventral vessels in this region being found near the orifice and on each side of the diverticulum. The intestinal vessel of Hoffmann does not reach the stomach. The vessels of the latter consist of a very close plexus formed around the opening of the diverticulum by the two marginal vessels and of vessels derived from this plexus, and extending along each side of the stomach as far as the siphon and connected by trans- verse tubes both on the anterior and posterior sides. The right- hand branch sends twigs to the mesentery between the diverticulum and alimentary canal. All these branches re-unite into a trunk which follows the course of the diverticulum up to the heart. Over the vascular parts of the digestive canal the epithelium is thicker and composed of larger and longer cells than the non-vascular parts. This epithelium is made up of several layers of cells, the deepest being rounded, small, closely appressed, the superficial ones very long, 10 or 15 diameters in length; below it is a delicate continuous elastic membrane. The connective tissue behind the membrane forms * Comptes Rendus, xciii. (1881) pp. 651-3; xciv., pp. 189-41. 628 SUMMARY OF CURRENT RESEARCHES RELATING TO two distinct lamelle ; the outer is dense, of equal thickness throughout, and remarkably refringent; reagents bring out in it the appearance of fine undulating fibrils; the inner layer is loose, with wide fenestre, and contains numerous cells and brown or yellow pigment-granules ; it is in the latter layer that the blood-vessels ramify; in the non- vascular parts it is thicker, except on the rectum. The alimentary canal-is provided with glands of two different types, viz.:—(1) Mucus-cells; large, oval, very numerous, placed among the epithelial cells; they occur in the second curvature, especially at its vascular parts. (2) Glands proper; they are pyriform and multicellular, the component cells radiating from the centre of the gland; each gland opens separately into the intestine, and lies in the loose inner layer of the connective tissue, but only in the region between the first opening of the siphon and the end of the esophagus. The nerve- ring surrounding the mouth is quite distinct from the blood-vessels, and is not embraced, as has been stated, by one of the latter. A further examination of the “heart” confirms the view of its glan- dular nature; it is broken up by trabecule into a number of cavities, containing cellular elements of two kinds, viz. either regular cells with distinct outline and tolerably refringent protoplasm, or cells with very irregular and indistinct outlines, with transparent but scanty protoplasm and granular nuclei, often two or three in number in the same cell; with these elements occur also brown or yellow granules, some of the yellow ones being aggregated into strawberry- like masses. Injection of the heart by way of the sand-canal shows that it communicates both with the madreporic plate and with the spaces of the connective tissue, and of the body generally; thus the blood probably undergoes some. modification in the organ, and is then in part carried into the general system and in part thrown off from the body, In Echinocardium flavescens the internal marginal vessel and the siphon are a little longer than in Spatangus, and they terminate at the point of junction between the second and third bends of the alimen- tary canal. This form also differs from Spatangus in possessing a small diverticulum or fecal reservoir in the rectum. Development of Asterina gibbosa.*—Professor H. Ludwig finds, as a general result of his important studies, that we have throughout the Echinodermata a mode of development which must be spoken of as a metamorphosis; the ground-form of the larva is an organism ciliated over the whole surface, with a2 mouth and anus on one side. By adaptation to different conditions of existence this ground-form has become variously modified as Bipinnaria, Pluteus, &c., which may be known as the secondary larval forms. The mature Echinoderm- form may arise either directly from the primary larva, or from a secondary larval form; or, further, one secondary larval may be followed by another larval form (e. g. Bipinnaria, Brachiolaria) ; but this interpolation of intermediate stages makes no essential difference in the course of the development. The processes by which the * Zeitschy. f. wiss. Zool., xxxvii, (1882) pp. 1-98 (8 pls.), ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 629 primary larva is converted into the Echinoderm appear to be essentially the same in all cases; all that happens in a more com- plicated history being the fact that in the secondary larve there is an absorption of. those larval parts which had themselves become secondary. The secondary characters are not to be regarded as having anything to do with the future organization of the Echinoderm, but as adaptations, proper to the larval life, and disappearing with its cessation. After giving a description of the mode of attachment of the eggs by the female, and the mode of fertilization, the author states that the two first cleavage spheres are almost equal in size; differences, how- ever, soon become apparent since one divides before the other. The results of cleavage are, not a solid morula, but a blastosphere with a unilaminate wall; the gastrula is formed by invagination. The absence of a morula would appear to be a constant phenomenon among the Echinodermata, and no other mode of formation of the gastrula than that by invagination has ever yet been observed. The mesoderm would appear to be generally derived from the endoderm, the cells wandering in the fluid of the blastoceel: some share, however, is taken by the ectoderm, and it may be perhaps justifiably supposed that this mesoderm presents indications of a bilateral symmetry. The gastrula-enteron is composed of two chief portions, a short cylindrical entrance, and a spacious vesicular terminal part; from the latter we have developed the enteroccel, the first signs of which are the appearance of an out-growing process on either side, the enteroceelic pouches. All this region is to be considered as bein essentially nothing more than a vesicular enlargement of the blind end of the primitive intestine. Up to and at this time the structure of the larva is still in all points bilaterally symmetrical ; but this symmetry soon begins to disappear, the enteroccelic pouches are no longer of the same size, owing to the much greater development of the left one. The external form also becomes altered, and on the fourth day there appears at the centre of the anterior side a de- pression of the ectoderm, which is the rudiment of the mouth and stomodeum of the larva. Towards the end of the fourth, or on the fifth day, the enteroccel becomes completely shut off from the larval enteron and the larval stomodeum opens into this latter. During the fifth day the rudiment of the water-vascular system becomes developed from the left enteroccelic pouch, and this outgrowth may be con- veniently spoken of as the hydroceel ; connected with it are the rudi- ments of the five primary vessels of the water-vascular system, which first appear as five slight outgrowths. Contemporaneously with the development of the hydrocc] we have the formation of the dorsal pore of the larva, which is dne to an invagination of the ectoderm, which becomes connected with the left enteroccelic pouch. With the exception of the observations of Kowalevsky on Psolinus brevis, the evidence of all embryologists would lead us to suppose that the history given of the hydroccel of Asternia is generally true of all Echinoderms. The author is inclined to look upon the dorsal pore, in its primary relations, as being a pore which led into the 630 SUMMARY OF CURRENT RESEARCHES RELATING TO enterocel, and that its connection with the hydroceel, therefrom developed, is only a secondary phenomenon ; this earlier relation is retained by the Crinoidea, where the primary pore opens into the enterocel. After discussing the further development of the hydro- cel, and the history of the blood-vascular system and permanent stomodeeum, the author passes to a description of the external form of the larva, where attention is directed to the so-called “larval organ,” or two cephalic lobes, the one smaller and anterior, the other larger and posterior, which form a special locomotor organ and are at the height of their development from the seventh to the ninth days. The wall of this organ consists of the three layers of the body, fine muscular fibres being developed on the outer side of the endodermal layer; the cavity of the organ is a development of the enteroccel, and the whole structure may be looked upon as being the homologue of the arms of a Brachiolaria. In an account of the development of the skeleton it is necessary to distinguish two groups of skeletal parts, both of which appear early ; to one are due the rudiments of the ambulacral pieces of the future arms, and to the other those of the primary skeletal pieces of the dorsal side of the starfish. A detailed study of the former shows that they arise in just the same way as in Ophiurans; the latter are developed in the mesoderm of the body wall, and on the seventh day eleven pieces may be made out; one of these always has a remarkably constant relation to the dorsal pores, and is the one which becomes converted into the madreporic plate; the pore does not primitively lie in the plate, but to the left of it; this relation is of significance when compared with what is seen in other Echinoderms; in Ophiurans the pore lies towards the left margin of the plate, and in Crinoids the primary pore has a similar relation to one of the oral plates. The other ten pieces do not all arise together, or exhibit the same rate of erowth ; five of them are the rudiments of the so-called “radialia,” or — better, “terminalia” of the arms of the starfish; within and alternat- ing with them lie the primary interradial plates, one of which forms the madreporite ; the eleventh piece occupies a more central position and is the rudiment of the central plate of the back. As the larva derived from the gastrula gradually passes into the young sea-star, the larval organs become lost, the “larval organ” and the stomodzeum of the larva being the last to be retained. On the ninth day, however, the larval organ decreases in size, till on the tenth or eleventh it forms nothing but a short stalked and knobbed process. This is doubtless the peculiar peduncle noted by Desor in a species of Hchinaster, and corresponds to the different structures to which L. Agassiz, Wyv. Thomson, and Philippi have directed atten- tion. After describing the history of the enteric tract, and especially the mouth, the author raises the question of whether there is a plane of symmetry in the young corresponding to the median plane of the larva; he thinks that none is to be, or indeed can be, detected; want of symmetry is one of the leading characters in Echinoderm structure ; yet this asymmetry is ordered by definite laws. If any radius or interradius is to be regarded as the ‘‘anterior” one, it must be that ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 631 interradius in which is placed the remnant of the larval organ, and is at the same time the anal interradius; when the larval organ and arms are both lost it may still be recognized by the fact that the madreporite lies just to the left of it, in a dorsal view. Attention is next directed to the nervous system, which had originally the form of an annular ridge encircling the point at which the mouth is afterwards developed ; the epithelium above the radial water-vessels thickens, and the radial nerves are developed from its lower layers; the rudiments are developed in an adoral and aboral direction, but before they reach the tentacles they swell out to form the eyes. Ludwig looks upon the ambulacral piates of Echinoids as being homologous with the adambulacral plates of the Asterid and the lateral plates of the arms of the Ophiurid; the primary interradials are homologous with the genital plates of Echinoids, and the five pairs of plates which are found on the actual edge of the interradials of the starfish correspond in position to the paired interambulacral plates of Echinoids, and so represent a first pair of interambulacral plates; the so-called odontophore which the author previously took to be an intermediate piece, is now regarded as an unpaired inter- ambulacral plate. In conclusion attention is directed to the corm-theory of Echino- derm structure which has been revived and pressed by Professor Haeckel, the author considering that no support for it is to be found in the developmental history of any Echinoderm. Brisinga.*—Professor EH. Perrier has some notes on this interest- ing starfish, based on a study of sixteen well-preserved disks, two young, and a large number of perfect, though single arms, in addition to a magnificent specimen which was almost complete. Such a series has, first of all, led him to the view that B. coronata and B. endecacnemos are only two forms of the same species; on the other hand, a new form, B. edwardsii has been dredged in the Atlantic; in this the arms are covered by imbricated plates, without spines. It is pointed out that in Hymenodiscus the whole skeleton is reduced to the ambulacral and adambulacral pieces, which, therefore, must alone be regarded as the essential parts of an Asterid. In Brisinga we have in addition, parts of the dorsal skeleton, which are arranged in arches, more or less closely set; these are, however, only found in the swollen part of the arms, where the genital glands are developed, and they are not to be seen in the young where the glands are still rudi- mentary; this set of plates must, therefore, throughout the whole Asterid series, be looked on as an apparatus specially applied to the purpose of protecting the reproductive glands. The disk of Brisinga is formed early in life, around a digestive sac, the prolongations of which are only developed later on; these different facts appear to support the doctrine the author has already taught, that the Echino- derm, like the Medusa or the Coral, is the result of the fusion of reproductive individuals around a central nutritive one. * Comptes Rendus, xciv. (1882) pp. 61-3. 632 SUMMARY OF CURRENT RESEARCHES RELATING TO In the young the disk consists of one central and nine large contiguous triangular pieces, some of which are interbrachial, and all of which carry large mobile spines, together with a few smaller plates, which alternate with these latter and are intermediate between them and the central piece, but considerable changes occur during growth; the central pieces become separated, the interbrachials are pushed to the edge of the disk, and, becoming placed exactly in the angle of the arms, they end by forming the odontophores. The madreporic plate is always formed on one of the plates of the first row of the disk; in Brisinga the forcing out of these plates stops when they reach the outer edge of the buccal ring; if the process of growth had only con- tinued and carried all these pieces on to the ventral surface, we should have had an Asterid with the ventral surface of an Ophiurid. Here then we see a considerable “rapprochement” between Ophiurids and Asterids, while the earlier arrangement of the plates of the disk seems to M. Perrier to recall the constitution of a Crinoid. Anatomy of Holothurians.*—E. Jourdan describes the testicular tube as being formed of three layers; au external cellular investment, a fibro-muscular zone, and a layer of internal epithelium, In Holothuria tubulosa the majority of the cells of the first of these are large and flattened ; some, however, are distinguished by consisting of a mass of refractive corpuscles within a delicate membrane ; these are feebly coloured grey by osmic acid, and are strongly coloured by methyl-green; the latter fact would lead one to suppose that they were young cells, while in their general appearance they are to be compared to fat-cells. In Cucumaria and Phyllophorus the cells of this layer can in no way be compared to ordinary epithelial cells ; and it would seem to follow that in some genera of Holothurians the peritoneal elements have acquired a special importance, inasmuch as the normal epithelial cells have completely disappeared. In the median layer we find a connective membrane overlaid by a layer of very fine circular muscles, identical with those which are to be found in the Polian vesicle. The study of the internal epithelial layer ought not to be separated from that of the spermatozoa; the sperm, if examined in spring or summer, is found to consist of a mass of large cells which may be regarded as spermatublasts; the cells of these bodies are similar to those which line the walls of the testicular tubes, and are found, when isolated, to be identical with them. Cells, likewise spherical, are also to be made out in which the protoplasm appears to be condensed into a very large nucleus, while first one, and then several, homogeneous refractive corpuscles appear in the spermatoblasts; the granular protoplasm at last disappears altogether, and in the place of the original spermatoblast we have a cell containing a number of cor- puscles, each of which represents a spermatozooid ; these have, when developed, a spherical head and a very long tail. Tt has been found that each tube of the so-called Cuvierian organ consists of a muscular sheath formed of bundles of longitudinal and a * Comptes Rendus, xey. (1882) pp. 252-4. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 633 layer of circular fibres; in the centre there is a mass of folded and spiral fibres, and in the axis of each tube there is a narrow, irregular canal, lined by cells containing granular protoplasm. By the con- traction of the muscular sheath the animal forces to the exterior the connective elastic mass within each tube; these become agglutinated with all the bodies with which they come into contact. Coelenterata. Tissues of Siphonophora.*—C. Chun, in his second paper, adds some facts as to the nervous system; he finds that the richly branched ganglionic cells on the upper surface of the disk are connected with one another by their terminal processes, in addition to which tri- angular connecting plates are developed at the points of division. Exceptionally large ganglion-cells lie on the radial muscular fibrils, and give rise to a kind of nerve-ring. Ganglion-cells are also to be found on the inner or chitin-secreting lamella of the ectoderm, but they are not so richly branched or so large; similar cells have been detected in the ectoderm of the air-sac, and the gastric polypites of Rhizophysa, and in the gastric polypites of Physalia. In these forms the ganglion-cells pass inwards, but in the ectoderm of the tentacle of Apolemia uvaria they remain superficial. As yet the author has failed to find nervous cells in the transversely striated musculature of the nectocalyces of Diphyes, where they might naturally be looked for; at the same time it was found on experiment that stimulation of one nectocalyx is carried over the whole colony. Ciliated and glandular cells are widely developed in the ectoderm ; the tentacular appendages at the base of the fishing-tentacles of Physalia are invested thickly by stinging-cells, among which long supporting and numerous glandular cells are to be made out. The supply of mucus in the Velellidz may be supposed to take the place of the absent fishing lines. The arrangement of the musculature which obtains in the Siphono- phora would appear to be that which is found in most Hydroids ; there are longitudinal fibres developed from the ectodermal epithelio- muscular cells, and transverse, or circular, endodermal muscular fibrils; the latter system would appear to be best developed in the air-bladder of Physalia, where in addition to the muscles ganglion- cells may be made out. Structures called ciliated funnels are described as being found in the endoderm of the middle third of a tentacle of Apolemia uvaria ; there may be seen three endodermal longitudinal ridges which can be followed almost to the tip of the tentacle; they consist of non-ciliated mucus-cells, with, on the surface, triangular ciliated cells, containing a coarsely granular protoplasm ; some of these are provided with a ciliated funnel and project freely into the body-cavity. The funnel widens out at its free end, where there are a large number of large cilia which bend over the surface of the cell, and keep upa constant movement. A canal may be made out which extends into * Zool. Anzeig., v. (1882) pp. 400-6. + See this Journal, i. (1881) p. 468. 634 SUMMARY OF CURRENT RESEARCHES RELATING TO the base of the funnel and there ends in a certain number of vacuoles ; the author has convinced himself that these remarkable structures are an integral part of the animal, but he is not able to make any generalizations with regard to them. In the highest Siphonophora the mesoderm is represented by the widening out of the lamella, at certain points, into a well-developed gelatinous layer. While in the lowest, the Calycophorida, an air-sac is absent, it only becomes more complicated as the organization of the Siphono- phore becomes higher ; in these, however, it is still lined by ectoderm, and never becomes, as Gegenbaur supposed, completely closed. Some of the cells of the ectoderm are of very large size; only one or two cells forming cecal processes 2 mm. long; the cells themselves may be 1 or 14 mm. long, and their oval nuclei measure -13-15 mm., so that they are among the very largest known in animal tissues. Development of Tubularia cristata.*— The development of Tubularian Hydroids has been a subject of some dispute. The latest paper, that of Ciamician,} describes an irregular segmentation resulting in an epibolic gastrula. This result, so out of accord with the development of other Hydroids, has been much questioned and denied, and H. W. Conn has accordingly made a careful study of the Tubularian embryo, in the case of T. cristata, avoiding the sources of error in Ciamician’s observations by removing the egg completely from the medusa and examining it by itself. In the result he finds that the development of T. cristata agrees completely with other Hydroids, the segmentation and formation of the germinal layers coinciding completely with Ccelenterates in, general. Tubularia, which has been considered somewhat of an anomaly in Hydroid development, presents, therefore, no noteworthy difference from the rest of the Hydroids. American Acalephe.j{—J. W. Fewkes is adding considerably to our knowledge of these forms. In discussing the characters of the Ctenophore Ocyroé crystallina, the author points out that, according to the classification of Chun, in which the Ctenophora are divided into the Tentaculata and the Nuda, the form in question would be placed with the non-tentaculate Beroé, with which it has few other anatomical likenesses. If Chun’s classification is to be followed Ocyroé must be regarded as a form connecting his two groups, and indeed it has, as A. Agassiz has pointed out, “structural characters of the Lobatz, Saccate, and Hurystome.” After describing Cassiopeia frondosa, the author comes to Linerges mercurius, which appears to be very abundant in the Gulf off the Florida Keys; one of its most interesting characters appears to be the characters of the “hood ” of the prominent otocyst; when this latter is looked at from above it resembles a spherical sac, in the centre of which a single otolith may be seen, seated on a short peduncle; the * Zool. Anzeig., v. (1882) pp. 483-4. + Zeitschr. f. wiss. Zool., xxxii. + Bull. Mus. Comp. Zool. Cambridge, ix. pp. 251-310 (10 pls.). ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 635 sac is regarded as being the homologue of the hood of other Disco- phora. In development an unequal segmentation is to be observed, and.as this segmentation takes place in the water we cannot regard the subumbral pouches as being receptacles for the developing young. During the ephyra stages the cavity of the stomach becomes differ- entiated into an upper and a lower story by the “ growth of a con- tinuation of the lower floor of the bell into a partition in this structure.” Stephanomia atlantica is a new species of that genus of the Sipho- nophora which is distinguished by the multiscrial arrangement of the swimming bells; the nectocalyces are much more numerous than in Agalma or Halistemma, and allow of more varied motion on the part of the animal, and a rotation of the stem is sometimes combined with a direct forward motion. Agalma papillosum, Agalmopsis fragile, Rhizo- physa gracilis, and Athorybia formosa are new species; in the last we find two different kinds of tentacular knobs hanging from one tentacle. Halitiara is the name applicd to a new genus of Hydroida; this Tubularian medusa has a tall bell with a small apical projection, four chymiferous tubes without lateral glands, four long tentacles with three small ones between each, and no otocysts. H. formosa n. sp. Another new genus is Halicalyz, H. tenuis; Aglaura vitrea n. sp., allied to and perhaps identical with the common A. hemistoma. Three new genera of Hydroids resulted from the explorations of the United States Fishery Commission: Calycopsis (C. typa) is related to Turris, but is distinguished by the presence of sixteen instead of four radial tubes, a point in which it differs from all known Antho- meduse ; Chromatonema (CO. rubrum) is a form the alliances of which are still somewhat obscure. Halicreas (H. minimum) has “ eight prominent rounded projections covered with tubercles on the bell margin at the extremity of eight radially arranged ribs passing from centre to circumference of the bell. No proboscis. No tentacles.” Apparently allied to the Narcomeduse, it differs from all of them in the presence of the eight radial stripes in the bell, and the eight marginal tubercles. There is a velum which indicates that it is a true Hydroid medusa. The author discusses the development of the chymiferous tubes in Mnemiopsis leidyi and points out the radical differences between it and Bolina, the history of which has been related by A. Agassiz. Sense of Smell in Actinie.*—Mr. W. H. Pollock and Dr. G. J. Romanes have found that the common sea-anemones are conscious of the presence of any kind of food (pieces of cockle, mussel, &c.) placed near them. If the food was held within a span’s breadth of an indi- vidual anemone the creature opened; if it was held in the centre of a circle of anemones they gradually opened in succession. The were found to be unable to localize the direction in which the food was lying. Dr. Romanes considers that the sense which is thus shown to be * Journ. Linn. Soe. (Zool.) xvi. (1882) pp. 474-6. 636 - SUMMARY OF CURRENT RESEARCHES RELATING TO possessed by these animals may most properly be called a sense of smell, and they are the lowest animals in which any such sense has hitherto been noticed. It was not found practicable to determine by experiments whether the sense is restricted to any special part of the organism or is diffused over the whole. Protozoa. Ciliation of the Hypotrichous Infusoria.*—J. van Rees, in a preliminary paper to a larger work on the marine Infusoria, describes in considerable detail the ciliation (more especially) of Styloplotes grandis n. sp. A new diagnosis is given of Huplotes longipes, whose ciliation is compared with that of the former. Species of Vorticelle.—Mr. W. Saville Kent in the third vol. of his ‘Manual of Infusoria’ gives a plate constituting a very useful key to the numerous species of the genus Vorticella, each of the forty-two species being represented in diagrammatic outline at its most typical condition of extension. Acinetide.{—E. Maupas has studied the forms obtained by him in Algiers and at Roscoff in Brittany, and describes at length Spherophrya magna, Podophrya limbata, Acineta pusilla, A. Jolyi, A. emaciata, A. foetida, Hemophrya thouleti, and H. microsoma. An im- portant observation is recorded as to the ingestion of food by S. magna. When an Infusorian is caught a rupture in its cuticle is produced at the point of contact with the tentacle. According to the author the axillary substance of the latter consists of clear homogeneous sarcode continuous with that of the body of the Acinetan, and this passes into the Infusorian, and probably accelerates its death. The tentacle now increases greatly in thickness, due without doubt to the afflux of sarcode from the Acinetan, from which a current is thus established in the direction of its prey, not, however, visible in consequence of the transparency of the sarcode stream. The latter mixes freely with the contents of the victim’s body, and loading itself with assimilable substances returns in the inflowing stream, which is so plainly visible by reason of the opaque granular particles held in suspension. This phenomenon is directly comparable with the sarcode circulation in the extended pseudopodia of Foraminifera or cyclosis in plant-cells, though in the former both streams are visible.f The author adds a full summary of the general facts which the special studies of the species have, in his opinion, established in regard to the structure and histological constitution of the Acinete, and some of the controversies which have existed on the subject. The first question considered is whether any naked Acinetide exist, destitute of all external covering, with bodies simply composed * Rees, J. van, ‘Zur Kenntniss der Bewimperung der Hypotrichen Infusorien nach Beobachtungen an Styloplotes grandis n. sp. und Euplotes longipes’ Amster- dam, 1881, 44 pp. and 1 pl. + Arch. de Zool. Expér. et Gén., ix. (1881) pp. 299-368 (2 pls.). + Of. for a discussion on the importance of this phenomenon Kent’s ‘Manual of the Infusoria,’ iii, (1882) pp. 803-5. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 637 of a mass of naked sarcode, without differentiation at the periphery into a membrane or other tegumentary layer of any kind. On the one hand, Stein and Fraipont consider all Acinetide without excep- tion to be provided with an integument; whilst Cienkowski and Hertwig affirm that they have vainly sought for any integument in Podophrya fixa, whose body is naked. After examining the arguments of either side, the author states his own adherence to the view of the latter, what he has himself observed in Spherophrya magna, still further supporting it. The periphery of this species is simply bounded by a thin cortical zone of hyaline sarcode, not distinct from the medullary sarcode, aud showing none of the differentiations proper to the true membranes with double outline. The existence of Acinetidz completely destitute of all covering membrane must, there- fore be considered a well-established fact. With regard to their integument the Acinetide being unicellular organisms, we must accept as a cell-membrane any peripheral layer with a double outline, which may exist closely applied to the surface of the body, and the author, after a long retrospective discussion of the views hitherto held (by Stein, Claparede and Lachmann, Hertwig, and Fraipont), states his own views. The Hemiophrya and Podo- phrya are provided with a single tegumentary covering which corre- sponds morphologically to a cell-membrane. The integument of Dendrocometes, Dendrosoma, Ophryodendron, and Irychophrya has the same value. The capsule, in which Acineta and Solenophrya are lodged, cannot, on the contrary, be compared to a cellular mem- brane, but is only a skeletal structure having no homology with the integument of the other genera. The existence of a second membrane within the shell, and applied to the surface of the body of the Acinete, has not been definitively shown in any species of this genus, and he is able positively to deny its presence in those which he has studied. The existence among certain Acinetide of two sorts of tentacles, one destined for seizing prey, and the other for its suction, is a well- ascertained fact which requires no further support. Although differ- entiated in their functions, the two kinds have, however, the same morphological value, and are evidently derived from the same primitive organ. Fraipont has given excellent reasons in support of this view, and to these the author further adds the fact that in Hemiophrya gemmipara both kinds of tentacles penetrate into the body, whilst in Hemiophrya microsoma, the sucking tentacles alone have this internal prolongation. There is here a gradation in the differentiation and specialization of structure, which added to other analogous facts men- tioned by Fraipont, shows that these two distinct forms are derived from one primitive form, which, in its structure and its relations with the body, must be similar to that which exists in Podophrya and Spherophrya. Fraipont calls this primitive organ a prehensile sucker, wishing thus to point out its double function of absorbing and seizing. Two very different opinions have been held as to the structure of the tentacles. On the one hand Claparéde and Lachmann define them as “ hollow tubes with contractile walls furnished with a sucker at Ser. 2.—Vot. II. y Ae 638 SUMMARY OF CURRENT RESEARCHES RELATING TO their extremity,” and Zenker (in describing Acineta ferrum-equinum), says “The internal canal of the arms is enveloped in two layers, one internal, voluntarily contractile throughout its whole length -and muscular, so to say, in its nature, the other external, inert, mem- branous, in continuity with the cuticular membrane of the animal.” On the other hand, Stein, Hertwig, and Fraipont describe the tentacles as composed of clear homogeneous contents, enclosed in a thin membranous wall. The author thinks that both these opinions are true, and that according to the species, the tentacles may be con- stituted with the two structures described by these authors. In certain species (Spherophrya magna, Acineta fetida and A. emaciata), the tentacles have a direct dependence on the peripheral zone of the body; in Hemiophrya gemmipara, on the contrary, they are organs become completely independent of the integument, perforating the latter and burying themselves in the substance of the body. Between these two extremes we find, in Hemiophrya microsoma, an intermediary arrangement in which the prehensile tentacles are a direct prolonga- tion of the tegument, whilst the sucker tentacles are formed of inde- pendent tubes, as in H. gemmipara. In very emaciated specimens of _ Acineta foetida, become very transparent, the author observed a different disposition of the tentacles. The two fascicules were in- serted at the extremity of a large tubular prolongation half invagi- nated in a deep depression of the body, and projecting a little beyond the opening of the shell. Having examined the structure of the tentacles and their relation to the body, the author turns to the solution of the question to what organs they can be compared in the general morphology of the Protozoa. Are they sui generis or can any homologues be found ? Koelliker, Haeckel, and Kent assimilate them purely and simply to the pseudopodia of the Rhizopoda and Radiolaria; Stein and Claus compare them to pseudopodia, but without affirming any real homo- logy; whilst Claparede and Lachmann, Hertwig, and Fraipont con- sider them to be entirely different. Here, again, the author considers that in all three views there is some truth if they are limited to certain species instead of being generalized. There is a great resem- blance between the tentacles and pseudopodia, both in regard to their structure and their function, but he would not, nevertheless, consider them as absolutely identical, the consequence of which would be to class the Acinetide with the Rhizopoda. They are organs of equal morphological value, between which there does not exist any essential difference of origin and nature and which consequently ought to be considered as homologues in spite of the particular differentiations which have managed to survive in certain types. The author has little to say of the nucleus, the structure and réle of which have been studied with so much skill by Hertwig, that sub- sequent observers, such as Biitschli and Fraipont, have only confirmed his observations. He adds, however, that the substance of the nucleus is not always as homogeneous as in Hemiophrya gemmipara, and that in it may be found a special histological structure, such as is seen in that of Acineta Jolyi, containing numerous perfectly spherical vacuoles, ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 639 each with a central corpuscle, or in that of Acineta felida, formed of a sarcodic network with irregular meshes. These two arrangements are also found, the former among ciliated Infusoria, Climacostomum virens and Uroleptus piscis, the latter in another Acinetan, Dendroco- metes paradoxus. As to the nucleolus, Stein affirms that no trace of one has ever been found, whilst Koch, Hertwig, and Biitschli do not refer to it. Fraipont alone states that he has found within the nucleus of Ophryo- dendron belgicum, Acineta tuberosa, and A. vorticelloides, one or more much darker corpuscles of nucleolar appearance ; but Koch has studied a species of the first genus and Hertwig A. tuberosa without finding any nucleolus, and the observations of Fraipont are too doubtful to be accepted. The author has, however, examined A. fetida and Podo- phrya limbata, and has always found a nucleolus ezterior to the nucleus, and similar in form and size to the nucleolus of the ciliated Infusoria. The animals were killed with a 1 per cent. solution of acetic acid or by the vapours of a solution of osmic acid of similar strength, then coloured with carmine, and after being washed, cleared with pure glacial acetic acid, for which was finally substituted glycerine, leaving it to penetrate in proportion as the acid evaporated. Our knowledge of the Acinetide is, in M. Maupas’ view, much too incomplete to definitely establish their systematic position in the Protozoa. Too much has been made of some of their resemblances to the Ciliata, whilst the considerable and fundamental differences have been neglected. If the author were asked to what group they have the most affinity, he would reply that they have much affinity with the Heliozoa. There is a great resemblance in the disposition, struc- ture, and the mode of action of the pseudopodia of the latter and the tentacles of the Acinetide. This resemblance is still more striking when we remember the manner in which Podophrya Trold, according to Claparéde, devours its prey, the suckers enlarging enormously and swallowing their captives, making them penetrate whole into the body, instead of sucking them slowly as in the other Acinetide. This mode of prehension of the food much resembles that of Actinospherium Eichhorni, and gives us one more link between the two kinds of organs. « Are we then to consider the Acinetans as derived from the Heliozoa ? I think that would be going much too fast. . . . Between these two groups of Protozoa there exist, particularly in the phenomena of reproduction, differences too great for it to be possible to admit a direct filiation. Let us be content for the present with having indicated their points of resemblance without wishing to deduce consequences to which perhaps they do not lead.” New Type of Porcellanous Foraminifera.* — Mr. H. B. Brady describes from the ‘ Challenger’ expedition a new genus and species (Keramosphera Murrayi), which illustrates a very distinct and inde- pendent type of foraminiferal structure not previously described, though closely related to certain well-known porcellanous forms, and presenting a certain analogy to Orbitolites. * Ann. and Mag. Nat. Hist., x. (1882) pp. 242-5 (1 pl.). 2x2 640 SUMMARY OF CURRENT RESEARCHES RELATING TO’ The test is free, porcellanous, spherical, formed of concentric layers, each consisting of a large number of chamberlets arranged more or less regularly in single series. Chamberlets of the same layer communicate with each other by short lateral stolons; those of the successive layers by the pores which formed the superficial aper- tures of the previous layer. Aperture consisting of numerous pores, one at the margin of each chamberlet. Colour white; surface areolated by the outlines of the somewhat convex chamberlets of the peripheral layer. Diameter about, inch(2°5mm.). Thespecimens were found in material dredged during the ‘ Challenger’ expedition at a depth of 1950 fathoms, in a locality, roughly speaking, about 25° south of the south-western corner of Australia. The material brought up was a nearly white, feathery-looking, diatom-ooze, com- posed chiefly of Diatomacez, Radiolaria, sponge-spicula, and other siliceous organisms. Foraminifera were not very numerous, about seventeen species in all; and the general aspect of the Rhizopod- fauna was distinctly arctic, except that the calcareous forms were as a rule somewhat thin-shelled. Bacterium rubescens Lank.=Monas Okenii Ehr.* —L. Olivier considers that he has established that the Bacterium rubescens of Prof. Lankester} is not a Bacterium, but is in reality Monas Okenu of Ehrenberg. The organisms were found by the author in the basins of the Jardin des Plantes at Paris, to which they gave a strong red colour. They were recognized by Prof. Lankester as being Bacterium rubescens. They are of a cylindrical form, slightly compressed towards the middle, and slightly swollen at the extremities. The greater axis measures from 0:02 to 0°3 mm., the smaller axis 0-008 mm. The body is colourless, but contains spherical globules of an intense red. These, instead of being disseminated here and there through the pro- toplasm, are more often arranged in a linear series, following the greater axis. They swim very rapidly, sometimes turning spirally round the greater axis, and progressing in a rectilinear direction. There are two distinct conditions of the organism, the one charac- terized by the great number of the red globules, the frequent division of the body, and the rapidity of the locomotion; the other by the dis- appearance of the red globules and the slackening of the movements, and of the tendency to transverse segmentation. Livery transition, from the first to the second of these stages, and even from the second to the first, is to be found. If we saw the elongated organisms, still active, but not in the condition of division, in a medium rich in nutri- tive substances, such, for instance, as broth sufficiently diluted with water, the little organisms will soon be seen to divide; and the segmentation may even be so frequent, that it sets in before the body of the animalcule has acquired one-third of the length it attains in circumstances where the segmentation is slower. The number of red globules diminishes in proportion to the activity of the organism. * Bull. Soc. Bot. France, xxviii. (1882) pp. 216-26 (1 pl.). + Quart. Journ. Micr. Sci., xvi. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 641 This coincidence between the disappearance of the globule and the lessened activity leads to the belief that the globule constitutes a reserve of material for the organism. To determine the animal or vegetable nature of the organism, the author employed various reagents. By distilled water they were slowly, and by glycerine, alcohol, and acetic acid instantaneously killed, the red colour disappearing slowly with glycerine, but rapidly in the case of the alcohol and the acid. A 1 per cent. solution of iodine is also a violent poison, causing the rapid disappearance of the pigment, and colouring the organism slightly yellow. Chloriodide of zine acts in the same way, but the colour is a brownish yellow. Iodine and sulphuric acid used simultaneously also give a brown colour if they are not too dilute. Picric acid gives a green colour and carmine red, but if they are used successively (the carmine last), the protoplasm is coloured green and the granulations red, the centre of each remaining clear. The periphery of the body is not differen- tiated from the central protoplasm. Finally, an alcoholic solution of hematoxylin gives no colour. After the action of these reagents no nucleus could be discovered, whatever was the stage of the life of the microbion, either in the diffe- rent stages of transverse segmentation or during the increase of the body in length, a fact which deserves attention, as it affords an instance of the division of protoplasm into two individualities without it having been possible to observe any previous differentiation of its constituent parts. There is also clearly no cellulose ternary vegetable envelope at the periphery of the body, as all the reagents which colour the proto- plasm colour the external portion, and vice versé. With fuchsin the colouring is general, as with carmine; it is of an equally intense red in the different regions, whether internal or peripheral. In the same way with Paris violet, it is impossible to distinguish the external membrane from the subjacent protoplasm. This membrane is, there- fore, simply a protoplasmic envelope, like that of the Infusoria, and cannot be compared to the cellular membrane of the Bacteria. The use of reagents leads us, moreover, to recognize the existence of organs very different from those which have been described among the Bacteria. In treating the organisms with a concentrated solution of Paris violet, we see at one of the two extremities, seldom at both, a filament, about 2 or 23 times as long as the body. It is very slender, and does not resemble the caudal prolongations which Koch has de- scribed as cilia among the Bacilli. It takes the same colour as the rest of the body. The existence and position of this filament leave no room for doubt, in the author’s opinion, that Bacterium rubescens is Monas Okenii. Ehrenberg and Cohn’s descriptions of the latter also agree in all points with that of B. rubescens. The filaments of Monas differ also from those of the Bacteria by their greater length and by the fact that they are cylindrical from their base to the free extremity. Van Tieghem considers the caudal filaments of the Bacteria to be prolongations of the cellular membrane, and not protoplasmic cilia 642 SUMMARY OF CURRENT RESEARCHES RELATING TO endowed with spontaneous movement. M. Olivier, therefore, thought it interesting to examine whether the same was the case with Monas Okenii, or whether, on the contrary, their long filaments are formed in a different manner. Tn a large graduated vessel 50 c.cm. of water was collected so rich in Monas Okenii as to be coloured red by them. One c.cm. of 1 per cent. osmic acid was added, and five minutes afterwards the vessel filled with distilled water, in order to weaken the destructive action of the acid. The next day all had fallen to the bottom, and by simple decantation an immense number could be collected in a very small bulk. Observed under the Microscope they presented different degrees of division. Those in which the segmentation was the deepest appeared to be entirely separated into two distinct masses. This is the case during life also. We then see two masses of the same shape opposed end to end, but leaving between them a transverse furrow which is quite colourless. When the Monad moves, these two masses move simultaneously, showing that they are united by a real though invisible tie. But if, when killed by osmic acid, they are subse- quently treated with Paris violet, that which before had the appear- ance of a hyaline furrow—a complete interval between the two segments of the body—immediately becomes coloured in the same way as the best characterized filaments. This portion appears to be in continuity with the protoplasm, no reagent distinguishing one part from the other. As the two segments of the body become further separated, this connection grows thinner and finally breaks. Although he did not succeed in following all the phases of this phenomenon in their successive order, the author “attributes to the connection which unites the two segments of the Monad the same nature as to the long and slender filament previously described. like this filament the connection is invisible without special preparation, but is easily recognized when coloured with Paris violet.” Cohn has remarked that the Monas in act of transverse division have a cilium at both extremities. But, in fact, one extremity is much more often destitute of any. The formation of a cilium at the free extremity of a Monad was never observed. The filaments, always cylindrical, are evidently flexible, for they present every imaginable appearance and position when coloured with Paris violet after being killed by osmic acid. Some experiments on dead organisms lead to the conclusion that the filaments are contractile, for on putting them into distilled water they in a few days disappeared; and this disappearance can only be explained by destruction or contraction. When the animals are fixed by osmic acid, left for some days in distilled water, and coloured by means of Paris violet, the filaments become visible ; and it therefore seems that the osmie acid, by in- stantly killing them, prevents a contraction which would otherwise take place. All these facts show that Monas Okenii does not resemble any species of Bacterium. Their organization, on the contrary, refers them to the nudo-flagellate Infusoria, as for example, Spumella. Like a great number of Infusoria (especially the Huglene), they seek the ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 643 light. The glass vessels in which they were kept were red at the side turned towards the light, whilst the opposite side remained colourless. If the vessel was blackened so that light could only penetrate through a small orifice, the Monas abandoned the dark regions and concentrated themselves in the light. This is not the only red organism that shows this attraction to light; and this cir- cumstance has led to its being confounded with an Alga which has the same colour, and is deposited in the form of large pellicles on the walls of vessels exposed to daylight. Claythrocystis roseo-persicina is thus often found associated with Monas Okenii. Oviform Psorospermie or Coccidia.*—A. Schneider gives the following as a provisional classification of the Psorospermiz :— Tribe I. The whole of the contents of the cyst are converted into a single spore. Monosporez. a. Spore enc!osing a definite number of corpuscles. Oligozoids. Corpuscles four in number. Orthospora. b. Spore enclosing an indefinite number of corpuscles. Polyzoids. Himeria. Tribe II. Contents of cyst becoming converted into a constant and definite number of spores. OLIGOSPOREZ, A. Only two spores. (Disporez.) a. Corpuscles of the spores in definite number. Cyclospora. b. Corpuscles of the spores in indefinite number. Isospora. B. Four spores. (Tetrasporee.) Corpuscle, one. Coccrdiwm. Tribe III. Contents of cyst becoming converted into a great number of spores. Potyspornm. Klossia, Benedenia. The author then describes three new genera (Orthospora, Cyclospora, and Isospora), with three new species, and two other new species of previously known genera. BOTANY. A. GENERAL, including Embryology and Histology of the Phanerogamia. Development of the Embryo and Embryo-sac.j—M. Treub states that Peristylus grandis furnishes an excellent demonstration of the fact previously recorded by him f{ that in the Orchidew the suspensor performs the function of a nutritive organ for the embryo. Some time after fertilization the embryo-sac is found to contain a small suspensor composed of a row of two or three cells. The upper portion of this soon grows rapidly, and finally protrudes beyond the exostome, putting out digitate much-branched protuberances, which creep over the funiculi and placente, robbing them of their non- nitrogenous contents for the benefit of the embryo; the cells of the * Arch. de Zool. Expér. et Gén., ix. (1881) pp. 387-404 (1 pl.). + Ann. du Jardin Bot. de Buitenzorg, iii. (1882) pp. 76-87 (3 pls.). See Bot. Centralbl., x. (1882) p. 356. t See this Journal, iii. (1880) p. 474. 644 SUMMARY OF CURRENT RESEARCHES RELATING TO suspensor often temporarily contain starch. Immediately after re- ceiving this supply of food-materials, the embryo, which had hitherto undergone very little change, alters in form and increases greatly in size, assuming the ordinary globular form of the embryo of Orchidez. In Peristylus the embryo appears to receive the whole of its nutriment in this way, while in European orchids a portion is derived from the ovule itself. Avicennia officinalis presents this peculiarity: that the two cells formed by division of the sister-cells of the embryo-sac are not, as is elsewhere the case, resorbed or compressed. A short time after fertilization the embryo-sac contains endosperm-cells which surround the embryo, and one large cell reaching to its apex, which the author calls the cotyloid cell. Subsequently the endosperm gradually emerges from the embryo-sac ; the embryo undergoes in the meantime further development, and after a time is covered only on one side by a thin layer of endosperm. In this layer a cleft is formed through which the cotyledons project, while the lower end of the embryo remains in the endosperm. The upper part of the cotyloid cell, together with the endosperm, projects out of the micropyle; while its lower part, still enclosed in the ovule, puts out protuberances on all sides into its tissue and into the placenta, which, after a time, it completely permeates like a mycelium. The cotyloid cell undoubtedly performs the same function as the suspensor in orchids, viz. that of a nutritive organ, carrying to the embryo, through the endosperm, the nutritive substances contained in the ovule and in the placenta. Embryogeny of the Leguminose.*—The following are the main results of an extensive series of observations made by L. Guignard on the development of the embryo and embryo-sac of a number of plants, mostly belonging to the Leguminose. His general conclusions do not confirm the theory of some writers that the nucellus of the embryo- sac is the homologue of a pollen-grain or spore. The axile hypodermal cell of the nucellus divides horizontally into two cells of variable size, the apical and the subapical cells. The apical cell either remains undivided or gives rise to a tissue of varying thickness, the “calotte.” This tissue is especially developed in the Mimosez and Cesalpiniez at the period of impregnation ; in the latter group it remains for a time after impregnation. The subapical cell (primordial mother-cell of Warming) may either remain undivided, and develope directly into the embryo-sac (Medicago, Melilotus), or it divides into a variable number of superposed cells, the lowermost of which (the true mother-cell) displaces the others, and alone developes into the embryo-sac. Cases are described in which the number of these cells is two, three, and four respectively. The order of formation of the cell-walls is usually basipetal ; they may be thicker or not than the neighbouring cell-wall. With possibly the single exception of Acacia albida, the embryo-sac is invariably the product of the lower- most cell, never of the fusion of two cells. * Ann. Sci. Nat. (Bot.) xii. (1881-2) pp. 1-166 (8 pls.). Cf. this Journal, iii. (1880) p. 473; i. (1881) pp. 69, 260, 620; ante, p. 64. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 645 It would appear, however, from observations made by other writers in the case of other plants (especially by M. Mellink on Agraphis patula) that there is a certain equivalence in the cells of the axile row, and that one or other of them may develope into the embryo-sac, but only one. Nevertheless, in some species the presence of two nuclei in the penultimate cell is nearly constant. The occurrence, or otherwise, of divisions in the subapical cell appears to depend on the greater or less rapidity of the development-of the embryo-sac. This tendency to division is even continued in the embryo-sac itself, but is arrested and reduced to the remarkable division of its primary nucleus into two parts, which separate to the two extremities of the sac. The formation out of this primary nucleus of eight distinct nuclei takes place in the way described by Strasburger ; but their exact position varies according to the form of the cavity. The upper nucleus divides into the oosphere, the two synergide, and a polar nucleus; the lower one into the three antipodals and a polar nucleus. The synergide are more or less closely attached to the summit of the embryo-sac; in the Mimosez they often attain a considerable length. The oosphere is inserted laterally, and descends below the synergide; its appearance varies considerably at the time of impregnation. The three antipodals are attached to the base of the sac, and are generally clothed with a thin membrane. In Phaseolus this is of considerable thickness; but it subsequently disappears, and the antipodals themselves have entirely vanished at the time of impregnation. In the Ranunculacee and Papaveracez, on the other hand, they survive this period. They are most developed in the Mimosez and Cesalpiniee. The fusion of the two polar nuclei takes place at different parts of the embryo-sac. It is completed before fertilization, except perhaps in the Viciee. The author regards all the cells formed in the embryo-sac of Angiosperms as representing endosperm-cells analogous to those formed in the embryo-sac of Gymnosperms. The oosphere forms by itself a greatly reduced archegonium ; the synergide are endosperm- cells adapted for a special function. The endosperm formed after ferti- lization by division of the secondary nucleus is the reeommencement of an interrupted development. With regard to the formation of the embryo, the first step is invariably the appearance of a transverse wall in the fertilized cell; but from this point great diversities exist, the differentiation of the subsequent product into embryo properly so called and suspensor not being constant. The entire absence of a suspensor had been noticed by Schacht, Treub, and others in a few isolated genera or species, chiefly monocotyledonous. Guignard now establishes that it occurs throughout the Mimosez and in some Hedysaree. When there is a distinct suspensor, it is differentiated at very different periods of development, according to the following six types :-— 1. The suspensor may be rudimentary, and never composed of more than three or four superposed cells (Soja, Amphicarpee, Trifolium). 2. It may be composed of two pairs of cells placed crosswise, the 646 SUMMARY OF CURRENT RESEARCHES RELATING TO uppermost attaining a considerable length, while the lowermost assumes a spherical form, both of these being remarkable for the constant plurality of nuclei (Viciez, with the exception of Cicer arietinum). 3. It may be formed of a filament of cells of variable number (Ononis). 4, It may consist of a larger or smaller number of pairs of cells, either superposed or in the same vertical plane (Lupinus), or in regular alternation (Cicer arietinum). 5. It may be composed of a greatly elongated cellular body, the cells of which are either (1) quite distinct from the embryo (Medicago, Trigonella, &e.), or (2) not completely distinct (Galega), or (3) much confounded with it (Phaseolus, &c.). 6. The cellular body may be an ovoid or rounded mass, which may differ as to the size, form, number, arrangement, and contents of the cells, and as to their relation to the embryo (Cercis, Anthyllis, Cytisus, &e.). In the same genus of Leguminose the type remains as a rule constant, but differs within the tribe. In the Fumariacez we find, on the contrary, Corydalis ochroleuca with a much-developed suspensor, while C. cava is entirely destitute of one. In the order Legu- minose we find every type that occurs in all the other natural orders. With regard to the formation of the embryo itself, after the primary transverse segmentation which immediately follows fecundation, some- times the lower cell is itself the mother-cell of the embryo, sometimes the mother-cell is not differentiated till after further divisions in the suspensor ; the first case occurring in Lotus, Tetragonobolus, Trifolium, Medicago, Anthyllis, Phaseolus, &c., the second in Galega and the Vicies. The first division in the embryo is not, as has often been stated, invariably longitudinal ; in the Viciez it is transverse. The epidermis becomes differentiated on the surface of the embryo before the appearance of the cotyledons. In embryos without sus- pensor, as those of the Acacieze, the internal tissues are most strongly differentiated ; in the Viciese, on the other hand, the cotyledons are already considerably developed while the axis is still very short and shows no internal differentiation. The size of the axis, as compared to that of the cotyledons, varies greatly. In most of the Mimosez it is very short, and manifests, long before it has attained any considerable length, the lobes of its first compound leaves. In this tribe also the synergide sometimes develope into embryos, indicating that they may probably partake of the nature of oospheres. The endosperm exists in the embryo-sac in two different states, either of free nuclei on the cell-wall, or of a parenchymatous temporary or permanent tissue; the second always succeeding the first, except in the true Viciee. The mode of multiplication of the endosperm-cells presents a close analogy to that of the suspensor; fragmentation is. a phenomenon associated with age. The first cell-walls always make their appearance at the summit of the embryo-sac, except in Lupinus. The free nuclei always divide simultaneously, as also do those of the ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 647 cells. Whether the endosperm is temporary or permanent, its cell- walls are always very thin up to the time when the embryo attains its full dimensions; then either its resorption commences, or it becomes gradually transformed into a solid permanent tissue. The presence of endosperm in the mature seed must be regarded as a sign of inferior organization. Its presence is not, however, always constant in the same genus, and it cannot be considered a character of primary importance in classification. The period of first formation of the endosperm varies considerably. In the Mimosez, Czxsalpiniew, and those Papilionacee where there is no suspensor, or only a rudimentary one, it begins to develope when the embryo consists of only about a dozen cells; while in those cases where the suspensor is more developed it originates considerably later. The suspensor, having very often a development in inverse proportion to that of the endosperm, or being formed considerably earlier, has undoubtedly in many cases, like tke latter, a function of supplying the embryo with nutrition, though in other cases it may serve no other purpose than that of fixing it. The author considers that these embryological facts do not yet enable us fo assign to the Leguminose their genctic position in the series of vegetable organisms. Development of the Ovule of Primula.*—According to F. Pax, the ovules of Primula elatior and officinalis are formed in basipetal suc- cession, but leaving the apex of the placenta and the part next the base of the ovary free. Between the ovules are formed, also basi- petally, and after the first appearance of the integuments, emergences of large-celled parenchyma, varying in size with the species, as also does the number of ovules, which is usually larger in the short- styled than in the long-styled form. The ovules are arranged spirally. d In P. Auricula and elatior the initial cell of the ovule lies beneath the dermatogen, and first divides by an anticlinal wall into two cells, which then divide periclinally, and one or both of the outer segments again anticlinally. The number of rows of cells produced by the periclinal divisions is increased by anticlinal divisions, and the der- matogen-cells are also found to divide anticlinally. When the rudi- mentary ovule begins to be elevated as a protuberance, periclinal walls are also formed on the apical surface of the protuberance in the first, ~ less often in the second layer beneath the dermatogen and anticlinal walls on its lateral faces in the first layer beneath the dermatogen. No differentiation can yet be detected into periblem and plerome; and the term endoblem is applied by the author to the tissue beneath the dermatogen. The endoblem finally forms a small-celled parenchy- matous tissue. The formation of the nucellus is preceded by a radial elongation of the cells of the outermost layer of endoblem, and the ovular protu- berance now becomes cylindrical, with a nearly rectangular longitu- * Pax, F., ‘Beitrag zur Kenntniss des Ovulums von Primula elatior Jacq. u. officinalis Jacq.’ 41 pp., Breslau, 1882. See Bot. Centralbl., x. (1882) p. 316. 648 SUMMARY OF CURRENT RESEARCHES RELATING TO dinal section. The nucellus is formed only in the lateral, not in the terminal corners. The two integuments are formed at the same time on one side only around and not out of it, appearing first at the apical edge of the longitudinal section, and growing also more rapidly here than at the parts nearest to the base of the ovary. ‘The inner integu- ment is clearly formed before the outer one. Both are developed out of the dermatogen, while in other genera it is only the inner one that has this origin. In the formation of the integuments an elongation of two cells in the case of the outer, of three in the case of the inner integument takes place on the dorsal side, their cells being separated from one another by a single cell. The elongation takes place in two slightly different directions. The outer integument is then formed on the dorsal side by the growth of the apical edge of the two cells, on the ventral side by periclinal and anticlinal divisions of originally at most five cells. The inner integument is formed on both sides out of three cells, the central one of which usually divides periclinally, the two outer ones by oblique walls. The thickening of the outer integument takes place by divisions parallel to the longitudinal axis in those cells which form at the time its innermost layer; the inner integument is formed also in a similar way, and becomes considerably thicker than the outer one. The cells of the innermost layer of the inner integument subsequently elongate in a direction vertical to the longitudinal axis. Special divisions take place in certain cells on the ventral side in connection with the curvature of the embryo-sac. The ovule of Primula is not strictly anatropous, but somewhat between the anatropous and campylotropous form. The origin of the formation of the nucellus consists in three hypo- dermal cells of the outermost layer of endoblem raising up the four or five dermatogen cells which lie above them, and giving rise to anticlinal divisions. The centre one of these three cells increases much more rapidly, forcing aside the other ones, which are completely resorbed in the epidermis. In the mother-cell of the embryo-sac arise two and sub- sequently two more transverse walls of considerable thickness and great refrangibility. The lowermost of the four daughter-cells compresses the three others which lie above it, until they finally constitute only a ~ strongly refrangible cap upon the mature embryo-sac. ‘The embryo- sac is fusiform and somewhat crescent-shaped; it contains two synergidee, an ovum-cell or oosphere, a small “ vegetative” nucleus, and three antipodals. The funiculus is formed out of the original ovular protuberance ; its endoblem is differentiated into periblem and plerome. The latter developes into a vascular bundle without xylem, composed only of cambiform, which ends directly at the embryo-sac. ‘The periblem is at first composed of a single layer of elongated cells, later of two layers, and finally of large cells destitute of protoplasm. Homology of the Ovule.*—L. Celakovsky gives a very minute description of a case of phyllody of the ovules of the columbine ; * Bot, Centralbl., x. (1882) pp. 831-42 ; 372-82 (1 pl.). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 649 discusses at great length the various theories as to the homology of the ovule and of its parts; and finally adduces arguments in favour of his previously published view that the ovule is homologous to a pinna or section of a leaf (foliolum), The ordinary position of the nucellus in the ovule is at first terminal; and it sometimes also occupies this position in monstrosities, especially when the ovular leaflet does not assume a distinctly foliar character. But when phyllody is strongly manifested, it is seen that the nucellus is not the true apex of the foliar leaflet, having a superficial lateral position. The morphological value of the nucellus is not affected by the question whether it originally occupies or only subsequently assumes a lateral position. Phytoblasts and their Pseudopodia.*—According to Prof. H. Baillon every vegetable or vegetable organism commences its existence as a phytoblast, the life of which may go through distinct periods, and which may have various degrees of complexity of structure. The phytoblast is of an albuminoid nature, like the lowest animals; and its reactions are proteid. Like truly animal substances, it is attacked by ammonia and by other special reagents; and behaves in every respect like animal sarcode. With its movements are associated pseudopodia, produced at the expense of its substance, usually internal, less often external. The movement of these pseudopodia is ordinarily slow, but sometimes more rapid, acting as arms to extend the organism to any neighbouring locality where the conditions may be especially favourable for its nutrition. During the growth of the pseudopodia cavities are formed inside it through which circulate a variety of nutrient fluids, one of these being the chlorophyll-pigment, though many phytoblasts are entirely destitute of it. Another frequent product of the phytoblast is the phytocyst, an external envelope of cellulose, mixed with a certain proportion of the superficial proteid substance; but which must be regarded only as a kind of carapace belonging to the moneroid structure which represents the phytoblast. A favourable object for observing the structure and movements of these pseudopodia is the hairs at the base of the stamens of Ficoidee ; within which are seen, in favourable conditions, proto- plasmic structures with a rapid oscillating motion resembling that of vibratile cilia. These pseudopodia coalesce when they meet, and the internal microsomes move rapidly from one to another. The author compares this movement to that of plasmodia, and regards it as forming an argument in favour of the animal nature of these phytoblasts or phytozoaires. Formation of Pollen-tubes,|—J.B. Schnetzler places pollen-grains of Narcissus poeticus in the mucilage from the stem of the plant. After about two hours, pollen-tubes begin to be formed, in which, at a temperature of 13° C., currents of protoplasm are very evident. The tubes thus formed vary greatly in form and dimension, while those * Bull. Soc. Linn. de Paris, 1882, pp. 297-8 and 313-4. + Bot. Centralbl., xi. (1882) pp. 104-5. 650 SUMMARY OF CURRENT RESEARCHES RELATING TO formed in the conducting-tissue of the stigma are moderately uniform. Pollen-grains of Leucojum cestivum immersed in the same way at 7 a.m. began to put out their tubes at 10.80; about 11.30 the tubes were twice as long as the grains; about 12.0 three times as long, and at 2 p.m. ten times as long as the grains; increasing in length about 0:1 mm. per hour. If the mucilage is too watery, the grains are liable to burst. Tinting with carmine-ammonia exhibits the development of the pollen-tubes very well when the mucilage in which they are immersed is sufficiently fresh. Cause of the Movement of Pollen-tubes.*—The penetration of pollen-tubes into the conducting tissue of the style is attributed by Sachs to unequal growth of the two sides; A. Tomaschek, on the contrary, considers it to be due to hydrotropism. When masses of pollen of Colchicum autumnale are placed in a hollow plum from which the stone has been removed, the pollen-tubes from the upper- most grains rise erect, while those which lie at the side incline downwards. Pollen-grains made to germinate in the open air display curvatures and even spiral windings, closely analogous to those of tendrils, which can scarcely be assigned to any other cause than revolving nutation. Apical Growth of the Roots of Phanerogams.j—S. Schwendener gives the following summary of results of his own and of previous investigators on this point :— 1. Most dicotyledons have a formative tissue over the apex of the root, the innermost layer of which is the young epidermis, the remain- ing layers belong to the root-cap. The originally simple row of cells of which the epideriuis is composed splits into two; the inner, and sometimes the outer one of these again divide. In a small number of dicotyledons layers of cells split off from the epidermis outwards, constituting the root-cap; the root-cap and the root itself having in these cases a common histogen. The formation of the root-cap is shared by the epidermis, which covers the apex of the root either in an undivided or in a split condition, and by the entire cortex or its outermost portion only. Monocotyledons have distinct histogens for the root-cap and the root itself; the epidermis is not in genetic connection with the root-cap; but there is a common primary meristem for both. Dicotyledons and monocotyledons present therefore this difference; that in the former there is a genetic connection between the root-cap and epidermis, but not in the latter. 2. The author confirms the statement of Eriksson that in dicoty- ledons the root-cap and epidermis proceed from a common histogen, the “dermacalyptrogen ”; although differentiated dermatogen cells take part in the formation of the cap. 3. There is no distinct histogen, as Hanstein asserts, for the vascular cylinder or plerome. - * SB. K. Akad. Wiss. Wien, Ixxxiv. (1881) pp. 612-5 (1 pl.), See Bot. Centralbl., xi. (1882) p. 12. Cf. this Journal, ante, p. 372. + SB. K. Preuss. Akad. Wiss., 1882, pp. 123-39 (2 pls.). See Bot, Centralbl., x. (1882) p. 389. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 651 4, As respects the number of apical cells, Eleocharis palustris has only one; while the Marattiacee have four. Phanerogams most often have several, not unfrequently four. In not a few cases, and especially among conifers and in some Leguminosz, the line of growth takes a peculiar course. At the apex is a column, the rows of cells which constitute it running parallel to one another and to the axis. This structure is regarded as indicating a transverse meristem composed of equivalent cells. 5. When distinct histogens occur in the apex, the walls which separate them are as thin as those of the histogen itself. Even roots, therefore, possess a special meristem from which branches proceed in two directions having no genetic connection with one another. Pitchers of Dischidia Rafflesiana.* —M. Treub describes the pitchers of this epiphytal liane, belonging to the Asclepiadez, which is rarely seen in Europe. The pitchers are seated on short axillary branches in pairs or opposite to very rudimentary leaves, and are themselves metamorphosed leaves, exactly resembling the ordinary leaves in their earlier stages. In contrast to Sarracenia and Ne- penthes, the outer side of the pitcher corresponds to the upper side of the normal leaves. The whole of the plant with the exception of the stomata, is covered with a close coating of wax, which extends even to the inside of the pitchers, and seems to preclude the possibility of these being organs of nutrition. They contain water, due apparently partly to rain, partly to transpiration. The only animals found in them were ants, which were always alive. Many of the pitchers were penetrated by the abundant adventitious roots ; and the only function which could be suggested for them was the accumulation of water, which is conveyed to the plant through these roots. Influence of Light and Air on the Anatomical Structure of Plants.j—J. Vesque and C. Viet give the following as the main results of experiments on this subject made partly in the laboratory, partly in the open air :— The combined action of light and of air more or less dry (i. e. of ventilation) is to accelerate the amount of transpiration, and hence (1) to increase the total thickness of the foliage; (2) to promote the development of palisade-parenchyma, either by the increase in the number of layers of cells of which it is composed, or by increasing the length of the cells themselves; (3) to promote an increased development of hairs, both in number and in length. The authors consider that these effects are produced not by one only of the agents, but by the two combined. Respiration of Plants.{—K. Godlewski has made a careful series of experiments on the relations between the gases inhaled and exhaled * Ann. Jard. Bot. Buitenzorg, iii. (1882) pp. 13-37 (3 pls.). See Bot. Centralbl., xi. (1882) p. 57. + Ann. Sci. Nat. (Bot.) xii. (1882) pp. 167-76. e trem Krak. Akad. Wiss., vii. (1881). See Bot. Centralbl., x. (1882) p- 5 652 SUMMARY OF CURRENT RESEARCHES RELATING TO by plants, chiefly by germinating, starchy, and oily seeds, ripening fruits of Ricinus communis and Papaver somniferum, and flower- buds of the last species. The following are some of the more important results :— 1. In the germination of both oily and starchy seeds, during the period of swelling, the volume of the exhaled carbonic gas is very nearly the same as that of the inhaled oxygen. 2. When access of oxygen is hindered, as when the swelling takes place under water, intramolecular respiration comes into play; and this may even continue after the seeds are exposed to the direct influence of the air. 3. When, in oily seeds, the roots begin to grow, the quantity of inhaled oxygen begins to show an excess over that of the exhaled carbonic acid. At the time when growth and respiration are most active, about 55-65 parts of carbonic acid are exhaled for 100 parts of oxygen inhaled. 4. The transformation of oil into starch is probably effected by each molecule of oil splitting up into three molecules of starch, together with carbonic acid, water, and other undetermined substances. 5. In the later periods of the germination of oleaginors seeds, not only the oil but also the carbohydrates formed from it, are used up in respiration; in consequence of which the volumes of oxygen inhaled and of carbonic acid exhaled become eventually equal. 6. In the germination of starchy seeds the volumes of the two gases remain constantly nearly the same, varying somewhat with different species. 7. In the case of expanding buds (of Papaver somniferum) the volumes of the two gases are the same. 8. In the case of ripening fruits containing oily seeds, a con- siderably greater quantity of carbonic acid is exhaled than that of the oxygen inhaled, a process of reduction taking place by which starch is changed into oil. : 9. Changes in the pressure of the oxygen cause corresponding changes in the energy of respiration. 10. But even when the energy of respiration is affected in this way, no alteration takes place in the relative quantity of oxygen inhaled and of carbonic acid exhaled. The relative proportion is affected only when the pressure of oxygen is so reduced that the amount of this gas inhaled is considerably diminished, giving rise to intramolecular respiration. 11. Intramolecular is no ingredient in normal respiration, which is the result of the direct action of atmospheric oxygen on living molecules of protoplasm; the former taking place only when normal respiration is hindered by a deficient supply of oxygen. 12. Under the ordinary conditions of normal respiration, intra- molecular respiration takes place only when a process of reduction is going on at the same time in the plant, as when carbohydrates are being transformed into oil. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 653 Oxalate of Lime in Plants.*—Dr. A. Poli publishes a full account of what is known respecting the occurrence of crystals of calcium oxalate in plants, including a complete list of those species in which they have been found, and a chapter on their physiological value. Dr. Poli’s own observations relate to species from a great number of natural orders, but chiefly from Labiatee. The presence of calcium oxalate is, he states, no characteristic feature of this class, several genera being altogether deficient in it. When present, if occurs in the greatest abundance in the rachis of the inflorescence. In some species of Salvia the crystals appear to be suspended in the cell-contents of the pith and cortical parenchyma, to be endowed with Brownian movement, and to be accompanied by grains of chlorophyll or starch. The clusters of crystals which occur in the extrafloral nectaries of Ricinus are first formed in the nectaries at the base of the cotyle- dons, around the vascular bundles. The young seedling has no crystals of calcium oxalate within its tissue until it has attained a height of nearly 0-1 m. and its cotyledons are fully developed. There are no crystals in the male flowers of Ricinus. Insects and the Cross-fertilization of Flowers.t—Doubts have been raised by M. Heckel and others, as to the réle of insects in the cross-fertilization of flowers; based especially on their supposed absence, or at least, their great rarity on the flowery summits of high mountains. The results of four years’ observations at Grenoble, by C. Musset, at all altitudes from 200 m. to 3000 m., and amidst one of the richest herbaceous floras in the world, are instructive. He finds (1) that all orders of insects have representatives up to 2300 m.; (2) that beyond 2300 m. Lepidoptera, Diptera, and certain Hymenoptera preponderate in number ; (3) that the number of genera, species, and individuals of nectar-loving insects is proportional to that of the flowers, and is sometimes incalculable ; (4) that the hours of sleep and waking of flowers, and those of insects, are synchronous ; (5) that the apparent number of nectar-loving insects is proportional to the number of their favourite flowers, and the state of the atmo- sphere and sky. M. Musset concludes that, as flowers and insects are never simultaneously wanting, the objection referred to against cross- fertilization is not well founded. B. CRYPTOGAMIA. Muscinee. Classification of Sphagnaceze.{—G. Limpricht explains more in detail the use of the character derived from the relative position of the chlorophyllaceous and the hyaline cells for the classification of species of Sphagnum. * Poli, A., ‘I cristalli di ossalato calcico nelle plante’ (2 pls.), Rome, 1882. See Bot. Centralbl., x. (1882) p. 311. See also this Journal, ante, p. 597. + Comptes Rendus, xcv. (1882). ¢ Bot. Centralbl., x. (1882) pp. 214-22. See this Journal, ante, p. 79. Ser. 2.—Vot. II. DO 654 SUMMARY OF CURRENT RESEARCHES RELATING TO The chlorophyllaceous cells of the leaves of the branches are compressed between the hyaline cells in one series on the inner, in the other series on the outer side of the leaf, forming, on transverse section, an isosceles triangle, with the free outer wall as its base. In the hyaline cells that wall is in consequence more convex which is more or less in contact with the adjoining hyaline cell at the apex of the triangle, although there is never any actual mutual coalescence. In the same species the prismatic form of the chlorophyllaceous cells may be replaced by a triangular, oval, or even a trapezoid form. In this mode of arrangement two groups may be distinguished :— 1. The chlorophyllaceous cells are compressed between the hyaline cells on the outer side of the leaf; the hyaline cells being therefore more convex on the inner side of the leaf:—S. recurvum, P. B., and var. speciosum Russ. (S. spectabile Sch.) ; Lindbergi Sch. ; molluscum Bruch; cuspidatum Ehrh. 2. The chlorophyllaceous cells are compressed between the hyaline cells on the inner side of the leaf; the hyaline cells being therefore more convex on the outer side of the leaf:—S. acutifolium Khrh. ; rubellum Wils.; Girgensohnii Russ.; fimbriatum Wils.; molle Sull. ; Austinit Sull.; papillosum and cymbifolium Ehrh., with its sub-forms S. subbicolor Hampe, and glaucum y. Klinger. 3. In the remaining species of Sphagnum, the chlorophyllaceous cells of the leaves of the branches lie exactly in the middle between the hyaline cells; either (1) free on both sides, when they are fusi- form or disk-shaped in transverse section, and the hyaline cells equally convex on both sides :—S, subsecundwm, N. vy. E.; laricinum Spr., and contortum Sch.; or (2) the very small chlorophyllaceous cells are elliptical in transverse section, and are equally enclosed on all sides by the hyaline cells, which mutually coalesce :—S. Wulfianum Girg.; Angstrémii Hartm. ; rigidum Sch. ; and medium. The squamosum group presents some considerable deviations from this structure. Fungi. Leucogaster, a New Genus of Hymenogastree.* —In beeeh- woods in Hesse-Nassau, R. Hesse found a number of fungi belonging to the Hymenogastrex, a group of Gasteromycetes which comprises the genera Hymenogaster, Rhizopogon, Hysterangium, Hydnangium, Gautieria, Octaviania, and Melanogaster. Among them he observe a hitherto unknown form, which he describes under the name Leuco- gaster liosporus, and regards as the type of a new genus which must be placed between Melanogaster and Octaviania. It resembles Melanogaster in the chambers of the gleba being filled with jelly in consequence of the swelling of the basidia; Octaviania and Hydnan- giwm in the form of the spores; but differs from all the other Hymenogastree in the structure of the membrane of the spores. The mycelium is not very massive, and consists of thin, at first colourless, septated, branched hyphe with very thick walls and occa- * Pringsheim’s Jahrb. wiss, Bot., xiii, (1882) pp. 189-94. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 655 sional swellings. The fructification varies greatly in form and in size from that of a pea to a pigeon’s egg. The peridium of the mature fructification is from 1:5 to 2°5 mm. thick, smooth, and composed of densely packed yellowish hyphe. The white shining chambered gleba resembles in structure that of Melanogaster and Hysterangium. The trama is readily distinguished from the hymenial hyphe, and is composed of a mass of extremely thin shining filaments, of which the hymenial filaments are elongated unseptated branches. The chambers of the gleba are usually polygonal, and are filled, as in Melanogaster, with jelly resulting from the swelling of those basidia which have already produced spores. The ripe spores are yellow, and about 0:02 mm. in diam. They are produced in the ordinary way in fours on the basidia, but without sterigmata. The membrane eventually separates into two layers, an exospore and an endospore; the exospore finally deliquesces into jelly; so that the ripe spore is at length surrounded with a smooth gelatinous trans- parent envelope, investing it like a sac. ‘The spores contain a dense fine-grained protoplasm, with small drops of oil. Parasites of the Human Ear.*—Loewenberg states that otomy- kosis frequently results from the introduction into the ear of the mycelium of fungi through the medium of ordinary oily substances such as olive-oil, oil of almonds, balsam, pomade, &c.; and he recom- mends as a substitute for these glycerine, which is not liable to the same objection. Disease is also caused by the occurrence of mycelial filaments in liquid medicinal applications, such as tannin, alum, zinc- vitriol, &c. The most extreme care must consequently be taken as to the purity of fluids for dropping into the ear, especially where the drum is perforated. He also adduces a case of ophthalmomykosis apparently caused by the presence of mycelial filaments in solutions of atropine and chlorine. The use of alcoholic in preference to aqueous solutions is recommended wherever practicable ; where the latter are indispensable, they should be boiled, or kept in so concentrated a state that the mycelia or spores of fungi cannot retain in them their power of growth, and diluted with freshly boiled water immediately before using. Chromogenous Schizomycete on Cooked Meat.t—In some experi- ments carried out by J. B. Schnetzler, pieces of fresh boiled beef, ten- dons, bones, and fat, exposed to the air but protected from light, became completely covered with a coating of a beautiful fuchsin-red colour. With an immersion lens magnifying 750 diam., this was seen to be composed of a gelatinous mass in which were imbedded multitudes of globular Micrococcus-cells about 1 » in diam. These presented all stages of transition between Palmella mirifica Rabh., and P. prodigiosa Mont. (Micrococcus prodigiosus Cohn, Monas prodigiosa Ehrenb., Zoo- * Loewenberg, ‘ Des champignons parasites de l’oreille humaine.’ Paris, 1889. See Bot. Centralbl., x. (1882) p. 405. { Bull. Soc. Vaud. Sci. Nat., xviii, (1882) pp. 117-9. 2 9 2 656 SUMMARY OF CURRENT RESEARCHES RELATING TO galactina imetropha Sette, or Bacteridium prodigiosum Schrét.); and Schnetzler believes Rabenhorst’s Palmella mirifica, described as occurring in similar situations, to be but a form of Cohn’s Micrococcus prodigiosus ; the differences in the size of the cells and in the color- ation being due to its occurrence on an animal instead of a vegetable substratum. The presence or absence of a gelatinous matrix is no distinctive character between the two species. During the formation of the red gelatinous matter on the meat, the temperature varied between 25° and 30°C. Cold alcohol extracted the colouring matter ; the rose-coloured solution became greenish yellow on addition of ammonia, acids colouring it red. Spectrum analysis showed a broad absorption-band in the green. We have therefore here a chromogenous Schizomycete which possesses the remarkable property of producing colouring matters from the elements derived from the substratum and from the air at a suitable temperature. New Bacterium sensitive to Light.*—Among the Schizomycetes which T. W. Engelmann has previously studied, with respect to the action of light, only one was sensitive to this action. This form, called on account of its colour, Bacterium chlorinum,{ disengaged oxygen in the light, and probably for this reason was attracted to the light when oxygen was deficient. He found, last year, a second form Bacterium photometricum, which reacted in a very high degree under the influence of light. It is slightly reddish in colour. The microspectroscopic eye-piece shows a powerful absorption of all the rays whose wave-length is less than 0-62 p, especially those between 0:62 and 0°59 (orange). The influence exercised by light on B. photometricum differs very remarkably, in many respects, from that shown by other motile organisms. In the first place the rapidity of the movements depends on it. In light of constant intensity the rapidity of the movements is, generally, in direct proportion to the luminous intensity ; more rapid, ceteris paribus, in the ultra-red and orange of the light of the sun or of gas, than in the other regions of the spectrum. In the case of prolonged action of light, especially of an intense light (and chiefly of the ultra-red and orange), the greater number of the bacteria become quiescent, this taking place directly when the ventilation is imperfect. This repose may be disturbed (all the quicker when it has been of shorter duration) not only by darkening, or a change of colour which acts in the same way, but also by any appreciable increase of light. When the luminous intensity diminishes suddenly, or when its quality (the wave-length) undergoes a change acting in the same way, the bacteria quickly retire, then stop for a time, and presently recom- mence their movements. The positive changes of the intensity or of the colour of the light do * Rev. Internat. Sci. Biol., ix. (1882) pp. 469-70. + See this Journal, ante, p. 380. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 657 no more than accelerate the movements, even when they are very great and rapid. The direction of the movements of progression changes in propor- tion with the intensity and colour of the light. In general, the bacteria move from less illuminated points to those which are more so, or from less active rays to those of greater activity. The converse only takes place when the luminous action is very intense. This results as much from experiments with glasses and coloured liquids as from observa- tions in the objective microspectrum.* In this spectrum, the bacteria accumulate chiefly in the ultra-red and in the orange-yellow. A third maximum (much weaker) is found in the green. In the spectrum of gas-light, the accumulation in the ultra-red is much stronger than that in the yellow; in the spectrum of solar light, the ultra-red only possesses a slight advantage in this respect. The crystalline lens and the aqueous and vitreous humours of four bullocks’ eyes in a fresh state, having been placed in a series between the gas-flame and the microspectral apparatus, this intercalation had no perceptible influence on the accumulation in the ultra-red; it was the same-on interposing a solution of alum in thick layers. The direction of the incident light appears to have little or no direct influence on the direction of the movements. Engelmann at first supposed that B. photometricum disengaged oxygen under the influence of light, and that the phenomena described might be essentially referred to modifications in this production of oxygen; but this presumption has not been verified. It has been im- possible to prove a disengagement of oxygen. The bacteria are also, relatively, but little sensitive to differences in the tension of the oxygen ; nevertheless, the increase of this tension acts, in almost all respects, in the same way as the increase of the light, and vice versa. The addition of a little CO, acts in the same manner as a sudden darkening. What seems most probable is that light excites in bacteria a specific chemical process of a reducing character, a process com- parable consequently to assimilation. Special experiments have shown that the action of the light cannot be attributed to changes of temperature. Connection of the Bacilli of Hay and of Distemper. t— In pursuance of his experiments on the mutual conversion into one another of the bacilli of distemper and of infusion of hay, H. Buchner reports the following results of experiments. The original form from which the distemper-bacilli were obtained, the bacterium generated in infusion of hay, and distinguished by the name Bacterium subtile, is marked by an extraordinary power of re- sistance to high temperature, and by having no power of causing fermentation ; requiring, therefore, for its nourishment free oxygen. The distemper-bacteria retain their infectious properties as long as desired at a temperature of 25° C. in solution of extract of meat, * See this Journal, post, p. 661. + SB. Akad, Wiss. Miinchen, 1882, p, 147. See Naturforscher, xv. (1882) p. 251. Cf. this Journal, ante, p. 89, nA 658 SUMMARY OF CURRENT RESEARCHES RELATING TO where they have the form of cloudy masses at the bottom of the perfectly clear nutrient fluid. If the temperature is raised to 36°, and the supply of oxygen increased by shaking, they multiply more rapidly, and at the same time gradually lose their infectious properties. In order to convert the distemper-bacteria rapidly into hay- bacteria, the solution which contains them is shaken up violently, to increase the supply of air, in a vessel to the sides of which pieces of filtering paper are stuck. Three transitional forms are thus obtained, which finally pass over into the bacteria of hay. The change is greatly promoted by the addition to the solution of extract of meat, of yolk of egg, and a small quantity of alkali. After standing for about 24 hours at a temperature of 36° C., a transitional form, the bacteria of white of egg, is obtained, which, in a slightly acid infusion of hay, is transformed into the innocuous hay-bacteria. The following is an epitome of the behayiour of these three inter- changeable forms of bacteria, which Buchner regards as adaptive forms of one and the same organism, Bacterium subtile :—1st medium. 1 per cent. extract of meat—(a) distemper-bacteria: solution clear, clouds at the bottom; (b) white-of-egg-bacteria: solution cloudy, floceu- lent, a mucilaginous pellicle, flocks and pieces of pellicle at the bottom ; (c) hay-bacteria: solution clear, with a firm, white, dry pellicle diffi- cult to submerge. 2nd medium. Slightly acid infusion of hay. (a) no increase ; (b) formation of a sparse white rim on the surface of the fluid; (c) dry pellicle, moistened with difficulty, and usually with a wrinkled or pulverulent appearance. Srd medium. The bodies of animals. (a) Infectious in very small quantities, producing dis- temper; (6) when multiplied a thousandfold, inactive ; in still greater quantities, infectious, producing distemper; (c) inactive even when present in the greatest quantities. Diffusion of Bacteria.—The researches of Pasteur and Darwin have shown how earthworms may aid the diffusion of small organisms, some of which may produce disease. Professor J. B. Schnetzler states that the dejections of earthworms always contain numerous living bacteria and their germs (the hay-bacterium included). It is clear that bacteria in enormous quantity float in the air about us; and we have at easy command, Professor Schnetzler points out, a small apparatus traversed by about 8000 cubic centimetres of air per minute, which may inform us as to those floating germs. This is no other than the nasal cavity, on the mucous surface of which air-particles are de- posited. 'To observe these he advises injecting the nose with distilled water (completely sterilized) by means of a glass syringe previously calcined. The liquid so obtained is put in one perfectly clean watch- glass and covered by another. With a Microscope magnifying 700 or 800 one finds, among various particles in the liquid, some real live bacteria. If the liquid be kept a few days in a clean glass tube hermetically sealed the bacteria are found to have increased very considerably. One sees Bacterium termo, Vibrio, Spirillum, Bacillus subtilis, even some Infusoria, and spores and fragments of fungi. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 659 Professor Schnetzler has further successfully cultivated the organized germs by means of a mixture of gelatine and distilled water. Why do not these bacteria in the nasal cavity always multiply and develope and penetrate to the windpipe and lungs? Their progress is doubtless opposed by the vibratory movements of cilia in the air-passages, and the weakly alkaline reaction of the nasal mucus may (it is also suggested) be unfavourable to some of them. Cohn has proved that bacteria producing acid fermentation perish in liquids with alkaline reaction. Infectious bacteria may, how- ever, multiply to a formidable extent on living mucous surfaces ; witness the growth of the micrococcus of diphtheria, brought by the air into the air-passages ; also the bacterium of anthrax. The bacillus of tubercle, as Koch has lately shown, may be transmitted from one person to another by the air-passages. Professor Schnetzler thinks hay fever may also be due to bacteria entering the nose. While the development of bacteria on normal mucous surfaces is usually limited, millions of them are found in the dejections of healthy children. Parasite of Malaria.*— From observations on a considerable number of malaria-patients, M. Richard is able to state that in all cases a specific organism is present. It inhabits and undergoes devyelop- ment in the red corpuscles of the blood; the first indication of its presence within the corpuscle is a pale spot which grows and developes black granules at its periphery ; it ultimately occupies the whole interior of the corpuscle, and then it ejects a collar with dark granules, and one or more delicate marginal processes; this is the parasite. It often oscillates with great energy for about an hour, even when not quite free from its host. The collar breaks up and sets free the granules which may be taken up by the white corpuscles. The “body No. 1” of Laveran appears to be a corpuscle containing a parasite whose development has been arrested. The comatose stage of the disease is produced by the blocking of the cerebral capillaries by blood-corpuscles containing parasites, in which condition they are very viscous and have lost their usual great elasticity. The appearance of the corpuscle when affected appears to demonstrate the existence of an investing membrane outside it. When the parasite is not abundantly present, Richard uses acetic acid to destroy the normal corpuscles, thus leaving the few affected ones readily visible. Parasitic Character of Cases of Malaria.j—A. Laveran’s account of this matter should be compared with that of Richard given above. He describes from the blood of malaria-patients three forms of parasitic elements. 1. Cylindrical bodies, with filamentous extremities, usually cres- centic ; length 8-9 », diameter on an average 3. Contour marked by a very fine line; body transparent and colourless, except at the middle, where there is a blackish spot composed of very dark red * Comptes Rendus, xciy. (1882) pp. 496-9. We gie xciii. (1881) pp. 627-30. Cf. Rev. Internat. Sci., iv. (1881) pp. 459-61. 660 SUMMARY OF CURRENT RESEARCHES RELATING TO pigment-granules. A very fine line is sometimes observed at the side of the cavity, and apparently serves to support the extremities of the crescent-shaped body. No movements appear to take place. The form is sometimes oval; and when it is but slightly elongated and the granules arranged in a circle, it closely re- sembles the other two forms. 2. Spherical transparent bodies, of the average diameter of a red blood-corpuscle, with pigment-granules often arranged in a circle when the body is inactive; in movement, they are agitated vigorously and become irregular in arrangement. At the margins very delicate filaments, slightly inflated terminally, often appear to be inserted; they move rapidly in every direction ; they have a length of from three to four diameters of a red corpuscle; three or four may occur upon one body; they cause an oscillation of the body, and displace adjacent blood-corpuscles. They finally become detached from the spherical bodies, and. , then range freely among the blood-corpuscles. 38. Spherical bodies of irregular form, transparent or finely granular, 8-10 in dia- meter, containing rounded pigment-granules of a very dark red colour, sometimes arranged regularly near the periphery, some- times aggregated at the centre or near the periphery. They are immobile, both as wholes and in their parts. They have been observed to result from the transformation of the body No. 2, and are probably the form which it takes at death. They have no nuclei, and are with difficulty stained with carmine. 4. Spherical transparent bodies like (2), but much smaller, viz. the smallest scarcely the 4 of a red corpuscle in diameter, and containing only one or two pigment-granules each; the largest have almost the diameter of a red corpuscle. ‘They occur either free or agereeated variously or attached to blood-corpuscles and appear to represent a phase in the development of the above parasitic bodies. Besides these four types, there occur red corpuscles exhibiting per- forations and pigment-granules, dark leucocytes, and free pigment- granules of various sizes. Out of ninety-two cases of palustric diseases of different kinds, these parasitic elements were detected in forty-eight, and their absence in many of the remaining ones may be due to the action of sulphate of quinine which had been administered to most of these, and which has been ascertained to have the power of destroying the parasite in blood removed from the body. The bodies cannot always be detected, they are most readily obtained just before the attack of fever and at its termination ; in chronic cases, they sometimes exist permanently in the blood. In the intervals between the attacks they probably lie in the internal organs, especially the spleen and liver. Pigment-bodies always occur in great numbers in the blood, especially of the small splenic and hepatic vessels, of subjects that have died of palustric affections. When death takes place owing to accidental circumstances, the bodies are found in such quantities in the blood as to tinge the spleen, liver, marrow of the bones, and sometimes the grey matter of the brain, a brownish, quite characteristic colour. Thus the dangerous symptoms of malarial ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 661 diseases are produced by parasitic elements which occur under different forms in the blood. Vaccinal Micrococci.—M. Straus presented to a recent meeting of the Société de Biologie at Paris a series of microscopical prepara- tions of the vaccinal pustule from the calf, at different stages of its progress, in which the presence of the special micrococcus could readily be observed. The method of preparation adopted was to place the excised fragments of skin in absolute alcohol, to cut sections and stain them by Weigert’s method (methylamine violet), and then discolouring them until only the nuclei, the bacteria, and micrococci remain visible. Under a high power, the latter were visible as extremely minute points, tinted blue, about a thousandth part of a millimetre in diameter, and grouped in colonies. They were seen in the borders of the inoculation wound, and in the Malpighian layer, and subsequently could be traced passing into the subjacent cutis, especially in the lymphatic spaces. The multiplication and extension of the organism seemed to coincide closely with the development of the pustule. Mucorini.*—Professor G. Bainier has published a useful mono- graph on these fungi. In a general introduction he briefly considers the systematic position of the Mucorini, their reproductive organs, mode of life, and methods and results of cultivation. The bulk of the work is occupied with the description of the species, twenty-seven of which are figured. It concludes with remarks on the importance of the Mucorini in the economy of nature. Alge. Disengagement of Oxygen by Vegetable Cells in the Micro- spectrum.t—T. W. Engelmann describes experiments on this subject. He has studied the relation between the wave-length and the assimi- lative action of the luminous rays by the “ bacteria method.” { For this purpose he has made use of a microspectral apparatus, con- structed under his directions by Zeiss of Jena. The apparatus forms a microspectrum at the plane of the object on the stage, and replaces in use the ordinary illuminating apparatus (mirror and diaphragm) of the Microscope. It is composed of, 1st, a plane mirror; 2nd, an arrangement with two slits, viz. a, a slit, with both sides movable by means of a micrometric screw and the breadth of which can be adjusted (with a range of 2 mm.) to about -001 mm. b. A slit movable, perpendicular to a; 3rd, a collimator lens; 4th, a direct-vision prism; 5th, an objective forming the spectral image of the slit. As it is useful to be able to vary the absolute size of the * Bainier, G., ‘Etudes sur les Mucorinées.’ 4to, Paris, 1882, 136 pp. and 11 pls. See very full abstract by Dr. Zimmerman in Bot. Centralbl., xi. (1882) pp- 115-52. + Rev. Internat. Sci. Biol., ix. (1882) pp. 465-7. Pfliiger’s Arch. f. Physiol., xxvii. (1882) p. 485. Bot. Ztg., xv. (1882) pp. 419-26 (1 fig.). ~ See this Journal, i. (1881) p. 962. 662 SUMMARY OF CURRENT RESEARCHES RELATING TO spectrum, it is advisable to have several different objectives. The sharpness of the spectra is such that some hundreds of Fraunhofer lines can be made perfectly visible. The luminous intensity, even when an ordinary gas-flame is used, is sufficient with a slit of 0:01 mm. wide to observe bacteria under a high power. By replacing the prism by a grating, the apparatus may also be adapted in a simple manner to the formation of a microscopic interference spectrum. ‘The results now communicated were obtained by means of the prismatic microspectrum. The first question examined was that of the relative extent of the disengagement of oxygen by the green cells in the different regions of the spectrum. In this examination two methods can be adopted, vizi—l. The method of simultaneous observation. 2. The method of successive observation. Simultaneous Method.—This consists in observing simultaneously the action of the different rays of the spectrum on different juxtaposed points of the same object. The object should have a regular struc- ture. Oonferve, Oscillarie, and some diatoms, are especially suitable. The object is placed in a transverse position in the microspectrum, that is, perpendicularly to the direction of the Fraunhofer lines, The following are the phenomena then observed. When the luminous intensity increases, starting from zero, the bacteria in repose in the immediate neighbourhood of the green cells begin to move first of all in the red, most frequently between B and C, and nearer to the latter. Increasing the intensity of the illumina- tion, the action extends on both sides to the commencement of the ultra-red and as far as the violet. The accumulation of the bacteria and the rapidity of their movement, remain in the beginning at their maximum in the red. With green cells (Huglena, Gidogonium, Cla- dophora), but not with brown (diatoms) and blue-green (Oscillariez), there appears in sunlight (not in gaslight) a minimum in the green about EK and a second maximum about F. When the bacteria are numerous, we see in such cases a kind of graphic representation of the relation between the wave-length and the assimilative energy, in which the abscisse are represented by the object and the ordinates by the respective depths of the layer of bacteria. In the case of very great luminous intensity the differences are reduced, because then the accumulation and the rapidity of movement become very great at all points. If, starting from the maximum, the luminous intensity decreases gradually, the different aspects just described are reproduced in inverse order. Successive Method.—In this method the object (preferably very thin) is placed successively in different parts of the spectrum, deter- mining each time the narrowest width of the slit at which the bacteria begin to move. The results confirm in general those of the first, as is shown by two tables given by the author. Tn one respect, viz. the situation of the maximum, the results of Engelmann differ very remarkably from those hitherto obtained by macroscopic methods by the best observers (Draper, Sachs, Pfeffer). These authors attribute to the yellow rays the strongest assimilative ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 6638 action.* This difference depends, he thinks, specially on the fact that with the previous methods it was necessary to operate on entire plants or leaves. We then have to deal with a greater or less number of superimposed layers of chlorophyll. Those chlorophyll-grains alone which are nearest to the surface receive the light almost un- altered ; on those which are deeper down the absorption produced by the first makes its influence felt. But this absorption is chiefly exerted, as is already proved by the microspectral analysis of a single grain of chlorophyll, on the rays between B and C, which, according to Engelmann’s experiments, are precisely those which are the most active, as well as the blue at F. On the other hand, the oxygen dis- engaged by the superficial chlorophyll-grains being generally only a small fraction of the total production of oxygen in the plant, it follows that the maximum action of the whole plant can no longer fall between B and C (and at F), but must be displaced in the direction of the green. The justice of this view has also been proved by experiments in which the light, before falling on a cel], has to traverse a thin layer of a solution of chlorophyll. With certain thick cells, very rich in chlorophyll (Cladophora for instance), the densest accumulation and the most rapid movement of the bacteria may be seen to be above the cell towards the yellow, and below the cell in the red. Disengagement of Oxygen by Hematococcus.t—The question whether the red unicellular alge can assimilate without chlorophyll has been lately decided by J. Rostafinski { in the affirmative, for reasons, however, which are not conclusive. T. W. Engelmann has examined this question by the bacteria-method, § and has obtained, even with specimens of a pure red apparently completely destitute of chlorophyll, a very marked reaction on the bacteria. The disengage- ment of oxygen was often tolerably brisk, especially in red light. The comparison of a great number of specimens of different colours showed however that, ceteris paribus, the disengagement of oxygen was so much the more considerable according as there was the more yellow or green observable in the colour of the cells. This gives rise to the presumption, that, even in cells apparently containing only red colouring matter, chlorophyll may still exist. By means of the microspectroscopic eye-piece of Zeiss, it has been found that there is in the spectrum of these cells a dark space corresponding to the chlorophyll-band between B and C. In the cells of the purest red this band was faintly visible only with a particularly favourable illumination ; it became more distinct in proportion to the greener appearance of the cells. * In view of these facts, it must be admitted that the above-mentioned absorption-band does not belong to the red colouring-matter, but arises from chlorophyll associated with this matter, and it may be considered as very probable that even the entirely red individuals of the genus Heematococcus only assimilate because they still contain chlorophyll. * See amongst others, Pfeffer, ‘Pflanzenphysiologie,’ i. (1881) p. 211 et seq., fig. 29. + Rev. Internat. Sci. Biol., ix. (1882) pp. 468-9. ¢ Bot. Ztg., xxxix. (1881) p. 461. This Journal, i. (1881) p. 930. § See this Journal, i. (1881) p. 962. 664 SUMMARY OF CURRENT RESEARCHES RELATING TO Hydrurus.*—J. Rostafinski gives the following diagnosis of this little-known genus of alge, which forms brown slimy flocculent masses in cold rapidly flowing water :—‘‘ Thallus hydrobius, lubricus, disco conico affixus, elongatus, usque ad tres decimetros longus, ex _uno podio principali, in medio latissimo, ramos laterales emittens ; inferne simplex, plerumque nudus, primo intuitu gelatinosus, in tactu duriusculus sed elasticus, solidus aut rarissime senilitate canescens ; semipellucidus, ochraceus; superne aut simplex aut penicillatus, varioque modo divisus ; semper tota sua superficie, ramulos minores filamentis tenuissimis obtectos, ex olivaceo fuscos aut nigros pro- ducens.” The peculiar mode of reproduction takes place only by night. The lower branches of the thallus begin to swell, and the gelatinous matrix of the cell-walls deliquesces and at length altogether disappears. The brown endochrome, previously in the form of bands or caps, collects into globular bodies which at length pass into a tetrahedral © form, furnished with projecting ridges or beaks. These develope directly into a new thallus. The nearest ally of Hydrurus is Woronin’s genus Chromophyton,t which does not necessarily inhabit the leaves of Sphagnum. The two genera agree in their gelatinous deliquescent cell-walls; but the reproductive bodies of Chromophyton have more the character of zoospores. Rostafinski proposes to unite them into a new family under the name Syngenetice. Relationship of Palmella to the Confervacez.{—Colonies of Palmella uveformis Ktz., gathered by J. B. Schnetzler in a small stream near Lausanne, were found to be composed of minute cells, about 0:01 mm. in diam., congregated into a gelatinous mass. Placed in spring water, and covered with a watch-glass, they produced zoospores, which swam about with great activity, and finally formed a green coating on the sides of the glass. Aftera time they germinated, and developed into a green alga composed of branched filaments of elongated cylindrical cells with lateral excrescences. Similar filaments _ also developed directly from the gelatinous cells of the Palmella. On evaporating, the cells separated from one another, assumed a globular form, and travsformed themselves back again into gelatinous colonies of Palmella. The filaments thus produced were a Stigeoclonium, or some nearly allied confervaceous alga. The water-bed in which the Palmella was originally found was sometimes full of stagnant or running water, sometimes completely dry; at that time the alga was accompanied by quantities of diatoms and by crystals of calcium carbonate. : These observations complete others previously made by Cienkowski and Famintzin on the disintegration of Stigeoclonium and of another confervaceous alga into Protococcus-cells, which have led Kiitzing and * Rostafinski, J., ‘ Hydrurus u. seine Verwandschaft.’ 34 pp. (1 pl.) Krakow, 1882. + See this Journal, i. (1881) p. 100. F + Bull. Soc. Vaud. Sci. Nat., xviii. (1882) pp. 115-6. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 665 others to the conclusion that the genéra Palmella, Protococcus, and Pleurococcus are simply phases in. the cycle of development of higher algeo, ; Division of Closterium intermedium.*—J. Schaarschmidt de- scribes the mode of division of this desmid as analogous to that of Penium interruptum. Tt has a primary suture, and a secondary suture in the middle of each hemicyst; and these present structures similar to the caps of Gidogonium. Before each division the cuticle is raised from the cell-wall in the form of a ring hollow on the inside, which splits on division, while the very plastic cell-wall rapidly stretches. The number of secondary and tertiary sutures, &c., may be very con- siderable, the author having noticed as many as twenty-four rings, indicating the number of times that the individual divides. He believes that all other species of Closteriwm with secondary sutures divide in the same way. Diatoms from the Island of Lewis.—Mr. E. W. Burgess sends the following list made from the examination of a diatomaceous deposit, new to Great Britain, from the island of Lewis, near Stornoway, which he thinks may be of interest to those working out similar deposits. It was found in the possession of J. Thompson, who was using it to polish sections of corals. The list has been submitted to Dr. Stolterfoth, of Chester, for verification of most of the species. Abbreviations :—vr. (very rare), signifies that only one or two valves have been found; r. (rare), about one on each slide; c. (common), three or four on a slide ; ve. (very common), the form most often met with on the slides. Prof. H. L. Smith’s arrangement has been followed, Tribe 1, Raphidiew. Family 1, Cymbelleew. Cymbella helvetica Ktz. c.; C. maculata Ktz. r.; C. scotica W. Sm. c. Family 2, Naviculee. Mastogloia sp. vr. ; Stawroneis anceps Ehr. r.; S. Phoni- centron Ehr. vr.; S. punctata Ktz. vr.; Nawvicula (including Pinnu- laria); N. angustata W. Sm. c.; N. acuta W. Sm. c.; N. firma Ehr. ? vr.; N. Hebes Ralp.c.; N. interrupta W. Sm. r.; N. gibba Ehr. rv. ; N. major Bhr. r.; N. ovalis W. Sm. vr.; N. rhomboides Ehr. ve.; N. viridis W. Sm. ¢.; N. viridula W. Sm.vr. Family 3, Gomphoneme, Gomphonema acuminatum Ehr. ¢.; G. capitatum Ehr. vr.; G. con- strictum Ehr. vr.; G. intricatum Ktz. r. Family 5, Cocconidee. Cocconeis placentula Ehr. vr.; C. Thwaitesii W. Sm. vr. Tribe 2, Pseudo-Raphidew. Family 6, Fragilariee. Epithema gibba Ktz. ve.; EH. proboscidea W. Sm. ¢.; E. ocellata Ktz. c.; E. rupesiris W. Sm. ¢.; H. sorew Ktz. c.; E. turgida W. Sm. r.; E. zebra Ktz. r.; Eunatia diadema Ehr. vr.; E. tetradon Ebr. c.; Himantidium arcus W. Sm. ve.; H. bidens Ehr. ve.; H. undulatum W. Sm. r.; H. majus W. Sm. ve.; Synedra splendens var. danica O'Meara J. D. vr. Family 7, Tabellariee. Tabellaria fenestrata Ehr. c. Family 8, Surirellez. Tryblonella angustata W. Sm. Tas * Magyar Noveénytani Lapok, 1881, See Hedwigia, xxi. (1882) p, 92. 666 SUMMARY OF CURRENT RESEARCHES RELATING TO Surirella linearis W. Sm. vr.; S. nobilis W. Sm. c.; Nitzschia linearis W. Sm. vr. Family 10, Melosireee. Melosira nivalis W. Sm. = Cos- cinodiscus Smithii vr. Family 15, Coscinodisceee. Cyclotella antiqua W.Sm.c. Also a form that for want of better objectives Mr. Burgess is unable to identify beyond that it is an Odontidiwm or Navicula. MICROSCOPY. a. Instruments, Accessories, &c. Bausch and Lomb Optical Co.’s Professional Microscope.—Fig. 113 (sent from America, and one of the best woodcuts of a Microscope which we have seen) shows the “Professional” Microscope of the above Company. Its specialities are the frictionless fine adjustment (described at p- 688), the glass stage and slide-carrier (described at p. 687), the centering of the substage (of which we have no detailed description), the two draw-tubes which allow of more than the ordinary variations of length, and the mirror and substage bars which are separate and can be moved independently of one another, or simultaneously when the arm on the mirror is placed in a recess in the substage bar. Bulloch’s Newer Congress Stand.*—This (Fig. 114) is made upon the original plan,{ with the exception of the stage, the con- struction of which has been modified. The stage (Fig. 115, Nos. 1-4) is held by a saddle-piece which is steadied by a strong brace passing down from the limb. It is entirely independent of the swinging of the mirror and substage. This saddle- piece contains a set of screws with perforated heads for centering the ring which supports the stage. These screws are so far back that the ring can be made very thin without reducing the strength or rigidity. The stage rests upon this ring. It rotates, and can be accurately centered by the screws in the saddle-piece. This stage is a revival of an idea which Mr. Bulloch says was used by Spencer thirty years ago. It consists of the ordinary stage-plate, having in its centre a large square hole. One side of this plate con- tains a wide dovetailed groove, in which slides a bar with its surface level with the top of the plate. At right angles to this bar is attached another bar. On this second bar slides a third bar, into which it has been dovetailed. The motion of this third bar is at right angles to the motion of the first. A thin plate is attached to the third bar, and lies flat upon the stage-plate. This plate is perforated, and holds the slide by means of a spring. It will be seen that this arrangement permits of motion of the thin plate in two directions at right angles to one another. Two pinions, perpendicular to the stage, control * Cf. ‘National Scientific Journal,’ i. (1881) pp. 230-1 (5 figs.). _ + See this Journal, iii. (1880) pp. 1076-8. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 667 Fic. 113. 668: SUMMARY OF CURRENT RESEARCHES RELATING TO Fig. 114. 90 93-70 60 refit file y ii ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 669 this motion; they work one through the other, and act upon racks placed at right angles. Scales placed at right angles serve as finders. Fic. 115. ww ee ee ee ee ee ee ee eee The substage is similar in design to that of Messrs. Sidle, de- scribed ante, p. 555, and a screw has been added to the base for clamping the base-plate which rotates on the tripod. Guillemare’s School Microscope.*—This (Fig. 116, 4 nat. size) is the design of Professor A. Guillemare, of the Lycée Charlemagne, Paris, and is apparently intended for junior pupils, its speciality being the screws V and V, by which both the tube and the slide are locked, so that they can only be freed by the professor with the aid of the key shown in the woodcut. * Journ. de Microgr., vi. (1882) pp. 233-5 (1 fig.). Ser. 2.—Vot. II. 22 670 SUMMARY OF CURRENT RESEARCHES RELATING TO The handle M, by which the instrument is held when passed round a class, is hollow, so that it can be placed on a vertical support, if desired. C is a metal cone polished inside, and we gather that at P is the arrangement for fine Fic. 116. focussing after the tube has been adjusted as nearly as possible and locked. Gundlach’s College Micro- scope.—This Microscope, till now called the “ Physician’s Microscope No. 1,” is shown in Fig. 117. Its speciality consists in the adjustments, of which there are four, thus described (from the maker's catalogue) :— “(1) A rack-and-pinion movement; (2) a sliding ad- justment of the body; (8) a micrometer-screw, and (4) a combination of micrometer- screws giving a slower motion than has ever been brought into use before. The racks and pinions are cut with some new and original tools and with the greatest exactness. “Gundlach was the first to think of the advantages of the combination of the sliding adjust- ment with the rack and pinion, and to bring out a series of Micro- scopes on this plan. The former allows the body to be removed for changing objectives; and, by combining the two, the body may be made to stand so high that first-class low-power objectives may be used on these stands. Lower powers may be used on them than most large stands will allow. “'The ordinary fine adjustment is by micrometer-screw acting on Gundlach’s new frictionless roller motion, patented in 1879. This motion is free from the fault of displacement of the optical axis, from so-called loss of motion, and from lateral motion, while it has twice the old extent of motion. .... “Tn working high powers, microscopists have felt the need in some work of a slower motion than that of the ordinary micrometer-screw, which cannot be made much finer and still be durable enough. This need is now supplied by the combination of two screws which give a resultant motion equal to the difference in the threads employed. One of these screws is a little coarser than the ordinary micrometer-screw, and may be used alone as a fine adjustment, and a change can be made instantly from this to the finer motion. Hither motion is given by one milled head next to the top of the pillar, and the change is made by turning a smaller clamping screw having its head over the ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 671 fine adjustment screw. By tightening the clamping screw, the adjustment is in order for the work of the combination ; by loosening, for that of the coarser screw only. As the thread of this Fic. 117 is a very little coarser than SoD ae the ordinary micrometer- screw, it alone gives a better motion for medium powers than the fine adjustment in common use, a second advan- tage of the invention. The combination of screws in use on these Microscopes gives a motion equivalent to that of a screw having three hun- dred and sixty threads to the inch. Any desired combina- tion can be made.” The stage consists of a strong, polished glass plate, made secure by a brass frame, which is nickel-plated. The glass plate has a hole in the centre, and is ground to permit the greatest obliquity of light. A new object- carrier, consisting of an orna- mented brass frame, with a rest for the object - slide, removable clips, and two handles, moves with evenness ie tressed by fever springs, Alli with double joint, to permit motion in every direction, and from which it is kept by frictionless pins that do not scratch the stage. The whole carrier can be removed and its place supplied with spring clips. The substage slides along the mirror-bar, thus keeping the diaphragm or other accessory concentrically with the mirror upon the object with central as well as oblique illumination. It can be removed without interfering with the mirror. The diaphragm is of novel construction, and is fitted to the sub- stage. It is of such form that it can be brought close to the slide, and its openings brought in use without changing its position on the mirror-bar. The mirror-bar swings to an angle of 45° above the plane of the object, allowing the mirror to be used as a condenser on opaque objects. The mirrors have their centre of motion around the point where the optical axis intersects the plane of the object. 22 2 672 SUMMARY OF CURRENT RESEARCHES RELATING TO Martens’ Ball-jointed Microscope.*—This (Fig. 118) is the invention (patented) of A. Martens, of Berlin, and is thus described :— In the observation of metals in their microscopical relations it is desirable to be able to give the Microscope the greatest possible power of movement, since the Fic. 118, objects for the most part do i not admit of small fragments being taken from them. A Microscope was originally made for the author by Zeiss, in which movability of the stand was obtained by three hinge- joints, which could be clamped up by a screw so that the tube remained quite firm at every angle; indeed it was firm enough to admit of a fine ad- justment being used. It was, however, too limited in its action, it worked properly only in a line perpendicular to the object, and in order to examine the neighbouring parts either the heavy object or the equally heavy instrument had to be moved. In the new construction the inventor has obtained far greater movability. Instead of the hinges, ball-joints of large diameter are made use of, the balls being hollow and clamped between two annular plates, placed unsym- metrically with regard to the centre of the ball. The plates are forced together by the action of a screw, a strong spring between them separating them again when the pressure of the screw is slackened. Thus a clamp, firm but readily loosened, is obtained. One or more ball-joints can be used for each stand. - Polarizing Microscopes.j—Prof. J. B. Listing objects to the term “‘ polarizing Microscope,” so commonly applied to the Nérrem- berg (or Hofmann) polarizing apparatus. The use of the name “ Microscope ” is not only incorrect in itself but it conflicts with that which properly belongs to a Microscope by means of which small objects are examined by polarized light, such as sections of minerals, crystals, hairs, muscle-fibres, &e. The objective of the true polarizing Microscope retains its ordinary dioptrical function, but in the other case no question of amplification comes into consideration (but rather a large angular diminution), the instrument without the lower collect- ing-lens being in reality an inverted astronomical telescope with the eye-piece turned to the object. * Zeitschr. f. Instrumentenk., ii. (1882) p, 112 (1 fig.). + Bericht wiss. Apparate Lond. Internat, Ausstellung im Jahre 1876 (A. W. Hofmann, 1878-81) pp. 367-8. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 673 Schieck’s Microscope with Large Stage.*—Prof. G. Fritsch writes that F. W. Schieck deserves special commendation “ for con- structing stands which, in regard to the size of the stage, very considerably exceed the ordinary dimen- sions without being either clumsy or unsightly. The ever increasing neces- sity for examining preparations of large size (such as sections of brain), or series of preparations on large slides, make such stages a pressing necessity.” Fig. 119 shows one of these stands with a stage 14 cm. wide. To prevent the slide from falling over the sides when moved to the furthest extent, two arms are attached to each side, the upper surface of which is on a level with the stage. When not required they can be turned back close to the sides of the stage. Projection-Microscopes.j—Dr. Hugo Schréder, in an interesting paper on lantern or projection-Microscopes, points out that the oldest forms originated in the earliest times of microscopical observa- tion, when the whole magnifying apparatus consisted of a simple bi-convex lens with very small aperture. In consequence, the : images had great depth, so that relatively ———————— thick objects were shown with distinct- ness. The images, however, by lamplight were exceedingly dim, if the power amounted to 100 or more. This was not, however, the only defect arising from the very small aperture, for the resolving power was also very insignificant, and the image was injuriously affected by the chromatic and spherical aberrations of the objective-lenses. As the result of these and other defects, the instrument was so unsatis- factory with regard to distinctness of detail that the same peepee lee was more efficient when used as a simple magnifying- glass. It will therefore be naturally asked in what consists the usefulness of the projection-Microscope ? Its utility is to be sought in quite another direction, and under certain circumstances it becomes highly important, if not indispen- sable. For purposes of demonstration there is nothing better than a good projection-Microscope. Many persons can examine the object at the same time, and a larger field of view can be obtained than would be possible with any other combination. ‘The angle of the image, which in the compound Microscope is at most 10°, can be increased to * Bericht wiss. Instrumente Berliner Gewerbeausstellung im Jahre 1879 (L. Loewenberg, 1880) p. 293 (1 fig.). + Central-Ztg, f. Opt. u. Mech., iii. 1882) pp. 2-4, 15-17 (1 fig.). 674 SUMMARY OF CURRENT RESEARCHES RELATING TO 40° or even to 60°, whereby, under equal circumstances, a 36-times larger surface can be viewed, and by 100 and more spectators. It is also very useful for pointing out to beginners particular parts of the object, in the same way as a drawing would be explained. The observation of the projected image requires no especial practice, as in the compound Microscope; and finally the image can be easily drawn or even photographed. Notwithstanding all these advantages, however, these instruments —called by Professor Petzval the “ chef-d’cuvre of optical art”—have | hitherto been very hardly treated. Usually the lenses of a compound, Microscope (often most unsuitable) were employed, and illuminating lenses with surfaces exactly convex, thus constituting a very indifferent instrument. The necessity of employing a heliostat, and the difficulty of always obtaining sunlight at the required moment, gave an impulse to the construction of the so-called lantern Microscope used only with artificial light, and in the last century Adams was celebrated for such instruments, which could be used in several ways, as simple, compound or lantern Microscopes. Their performance was best as simple, mode- rately so as compound, and very inefficiently as lantern Microscopes. Much later, when achromatic objectives were introduced, Chevalier in Paris and Duboscque constructed much more complete instruments, and in modern times Foucault invented the excellent photo-electric projection-Microscope. At first sight nothing seems simpler than to construct a good lantern Microscope since we have only to replace sunlight by lamp- light. This is, however, not the case, for on further consideration it will be found that the conditions which are so favourable with sun- light cannot be maintained with any artificial light—we can only approximate to them. ‘The intensity of all artificial illumination, even the strongest electric light, is considerably less than that of the sun; besides, all strong lights have far too large an illuminating surface to give distinct images with many fine details. The earlier lantern Microscopes had the worst possible illumination, for good oil-lamps did not then exist. If petroleum or gas lamps be used, it will soon be found that the magnitude of the flame in no way heightens the effect; although the image surface may appear to be more brightly illuminated, the contrast between the light and dark parts will be less—the absolute intensity is greater, but the relative smaller. If we follow the course of the illuminating rays it will be seen that the flame limits light diverging in all directions. Divergent light cannot, however, be employed for the illumination of an object, but we must always have convergent light. The source of light is therefore placed in the first focal point of a convex. illumi- nating lens and the object in the second. The nearer a lens of given diameter is to the source of light, the greater will be the aperture- angle of the illumination; the greater the quantity of light utilized the further off will be the second focal point and the less the con- vergence of the rays upon the object. The convergence of these rays must, however, correspond with the final convergence of those which limit the field of view, and therefore, for all the rays falling on ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 675 the first illuminating lens to be utilized, a second condition must be fulfilled, viz. that the image of the source of light which falls on the object must not be larger than the object itself. Since the source of light and its image are as the two focal lengths it is obvious that these conditions can only be strictly fulfilled with very low powers and under very favourable conditions. With higher powers the greater part of the light is lost for this reason, that the intensity of the light with the higher powers diminishes not with the second, but approximately with the third power of the amplification. The greater part of the light from the lamp does not fall on the first illuminating lens. In order to utilize as much of this portion as is possible the attempt has been made to concentrate by means of large concave mirrors the light which is lost on the side opposite to the condensing lenses. The mirror—which should be concave— must have the flame in its centre of curvature, the image of the flame, therefore, coinciding with the flame itself. As this is trans- parent, only a small portion is lost by absorption, and the part that is utilized follows the same direction as the other rays. This condition is absolutely necessary, in order to avoid light- nodes in the illuminating cone produced by two different con- verging rays, whereby the clearness of the image is materially affected. It is thus evident that with all ordinary flames only the seg- ment of a small circular surface is utilized. The flat flames, the narrow edge of which is used (as for example in the Sciopticon), give the best results. On account of the too great extent of the illumi- nating surface, lighthouse lamps, which consist of a number of concentric wicks, only yield a very moderate result, notwithstanding the quantity and intensity of their light. Fresnel’s ring-lenses are also unsuitable. Illuminating lenses of the smallest dimensions and the largest aperture angle (as near as the temperature of the flame will allow) give the best results. It is also advisable to insert a movable lens between the object and the illuminating system, in order to regulate the convergence of the light according to the requirements of the objective employed. To obtain a perfectly uniform illumination of the image-surface it is further necessary that it should not be the image of the source of light produced by the illuminating lens that falls on the object, but a neighbouring aberra- tion-circle, in which the light is uniformly distributed. (Petzval has already drawn attention to this.) Besides lamplight the Drummond lime-light has been employed very satisfactorily, and after many experiments Dr. Schréder considers it the best on account of the small and intensely illuminating surface of the lime and its pleasant light. In spite of its intensity, the magnesium-light gives no satisfactory result, because it does not burn steadily, and even when a ventilator is employed, the lenses are covered with the burnt magnesium. The electric light is excellent on account of its large intensity in a small space, but its unsteadiness is objectionable. The Jablochkow candle is most suitable, notwith- standing its small intensity, if a uniform height can be maintained. The incandescent light is too small in intensity, and too oblong. 676 SUMMARY OF CURRENT RESEARCHES RELATING TO Tf in course of time the electric light is more perfected a new epoch will commence for the lantern Microscope, and this highly interesting instrument, in a compendious form, will certainly not be wanting in any wealthy (gebildeten) family. The objectives must of course be as free as possible from spherical and chromatic aberration, and must form a perfect image of the object, not only in and near to the axis (as in the ordinary compound Microscope), but over the whole extent of the image-surface, a by no means easy matter with large apertures. Dr. Schréder has constructed a projection-Microscope for the Microscopical Aquarium at Berlin, and a considerably more improved one for North America, the first of which is shown in Fig. 120. Fig. 120. The source of light is at a; b and c are plano-convex lenses of crown glass, between which at p an alum cell is interposed to inter- cept the heat rays. The rays emerge from ¢ strongly convergent, but are made parallel and corrected for spherical and chromatic aberra- tion by the combination de. The parallel beam s is made convergent by the movable lens faccording to the requirements of the field of view. For polarized light a large Nicol prism can be placed at s, and selenite plates at u. The analyser is attached to the objective. By means of a silver prism g the illuminating beam is thrown upon the object J vertically “in order to admit of using receptacles for holding living animals in fluid, &c.” The objectives m, m' are attached to a revolving holder o, o’. Powers from 100 to 2000 can be used. They are focussed by the screw 7, the upright piece ¢ serving for revolving the holder when a different power is required. ; The rays after having passed through the objective are reflected by a silvered prism / horizontally through the negative achromatic lens h’, and form an image at q. The American instrument has immersion lenses giving a power of 4000 times, and can be used for opaque objects by means of a large Lieberkuhn. “ Notwithstanding the many reflecting surfaces,” Dr. Schréder says that “with only an ordinary petroleum lamp the larger diatoms such as Triceratium favus can be very distinctly seen. With the oxy- ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 677 hydrogen light living diatoms and sections of plants are extraordinarily beautiful, all natural colours appearing very bright. With a power of 2000 the cornea of a fly occupies the entire field of view, and the fine vitreous membrane in each cell is seen magnificently.” Rock-sections can also be well shown in polarized light. Apparatus for Projecting an Image to any required Distance with Variable Amplification.*—For lectures it is often desired to throw on the screen an image of an object with a given amplification, and in order to vary the amplification, several auxiliary appliances have hitherto been brought into requisition. A. Crova has devised a means by which, with the same distance of the object from the screen, the amplification may be changed with the aid of only one additional piece of apparatus. He places between the object and the screen two lenses of equal focus, one plano-convex and the other plano-concave, their distance apart being capable of being altered as required. The plano-convex lens is fixed in a frame which is fastened to a horizontal brass rod resting on the stand, and along this rod the other lens (similarly fixed in a frame) is made to move by rack and pinion. The lenses have a focus of 0°15. By means of divisions marked on the rod the lenses can be set at the distance required ; when the plano-concave lens is at zero the two lenses are completely in contact, and their optical centres coincide; according to the distance between the lenses the converging or diverging effect of the system predominates. Waechter’s Travelling Dissecting Microscope.t—This, Fig. 121, Fia. 121. * Journ. de Physique, 1881, p. 159 (1 fig.) t Bericht wiss. Instrumente Berliner Gewerbeausstellung im Jahre 1879 (L Loewenberg, 1880) p. 302 (1 fig.). x 8 ye 1879 (L. 678 SUMMARY OF CURRENT RESEARCHES RELATING TO by P. Waechter, of Berlin, is specially adapted for travelling, as when closed, it forms a box of only 10 cm. in length by 10 em. in breadth and 7 em. in height. The two halves of the cover a, opening right and left, serve as supports for the hand. Inside the box is the stand b with the stage and mirror, as well as the receptacles c for keeping the three achromatic objectives of 15, 25, and 40 power. ‘The re- maining space can be utilized for other apparatus. Measurement of the Power of Eye-pieces.*—Dr. Royston- Pigott originally suggested the placing of the eye-piece in the sub- stage and throwing an image of a rule, supported at a distance of 10 inches from the diaphragm of the eye-piece, upon a stage micrometer. Mr. W. H. Bulloch having found considerable difficulty in getting the lines of the rule sharply defined, has devised an apparatus consisting of an ordinary Microscope with an objective of 2 inches focus, used to examine an image of a diaphragm, formed by the eye-piece to be measured. The exact size of the diaphragm and its distance from the eye-piece being known, the size of the miniature image formed by the eye-piece can be readily measured, and a simple calculation then gives the magnifying power. Hall’s Eye-protector for use with the Monocular Microscope.t —Dr. L. B. Hall describes an appliance to be used with the mono- cular instrument, for the purpose of protecting the unemployed eye, pointing out that the employment of one and the same eye at the tube of an optical instrument is the same practice that cost the squinting eye of childhood its power of vision. So many of us are contented at _ having trained one eye to do acceptable work, that we think we cannot spare the time to discipline the other. If this process ended when the head is withdrawn from the instrument, the practice would be less dangerous, but the trained eye finding an unequal companion, performs reading and all other near work with greater ease than its fellow ; sees So much more distinctly that the other is left without exercise, except for large objects, and becomes of less and less value as the process goes on. Dr. Hall could point, he says, to those who have - practically lost one eye by this process, and estimates that one-half of all those who have used the monocular Microscope to any con- siderable extent during five years are monocular men for all fine work, meaning by this that every such person who can “resolve ” one of the more difficult tests with one eye will find himself unable to do so with the other. How often have we heard persons exclaim, upon looking into a binocular Microscope for the first time, how much easier it is to see with the instrument, and this with one field quite dark; such ex- pressions are not to be ascribed wholly to dissimulation, or flattery, and for the following reasons, viz.:—When both eyes are left open and one is applied to an instrument, the two images, being unlike, * Amer. Mon. Micr. Journ., iii. (1882) pp. 103-4 (1 fig.). ‘The Microscope,’ ii. (1882) pp. 83-4. + ©The Microscope,’ ii. (1882) pp. 88-90 (from the ‘Medical and Surgical Reporter ’), vi ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 679 confuse each other in the natural endeavour to blend them. This requires a mental effort to exclude the impression upon the retina of one eye and regard that upon the other only. Again, when we close one eye by contraction of the orbicular muscle, or by pressure, as by the hand, we cause contraction of the accommodating muscle also, and of the other eye as well. : To facilitate the training of both eyes the following eye-protector is proposed. It consists of a small, opaque disk near the eye, sup- ported by a wire extending from its outer edge downward, to a point on the tube low enough to be out of the way of the nose, then bent upward, parallel to the tube, but not touching it, and attached toa ring near the top. Dr. Hall’s is made of a piece of brass wire, No. 18, about 45 cm. long; a loop at one end, 4 cm. in diameter, covered with a piece of black paper folded over and gummed down, forms the disk. At the other end is a ring to fit the draw-tube, and then the intermediate wire bent.- It is attached below the flange, on the draw-tube, where there is no lacquer to be scratched, but if it should be thought desirable to attach it above the flange, then the ring ought to be covered with chamois, so as not to wear the polish. The advantages of this form are, the small size of the disk and its support, interfering with the working of the instrument and view of the stage as little as possible. The support is not in the way of the nose; it is elastic, not uncomfortable when touched by the nose, and striking it does not displace the stand; it can be rotated about the tube and used with either eye alternately ; it can be easily adjusted to the eye-distance of any worker ; and, lastly, it is of so simple a con- struction that any one can make it for himself at a very small cost. Cramer’s Camera Lucida* (also Hofmann’s and Oberhauser’s). —Dr. C. Cramer can only concur to a small extent in the warm praise which Dr. H. von Heurck has bestowed upon Hofmann’s camera lucida.t Besides the advantage of having the paper lie * Bot. Centralbl., vii. (1881) pp. 385-91 (2 figs.). t+ Hofmann’s camera lucida was described and figured in this Journal, ii. Fie, 122. | (1879) p. 21. We, however, add here a diagram of it (Fiz. 122), 8 being the silvered mirror over the microscope-tube, s? the smaller silyered mirror which 680 SUMMARY OF CURRENT RESEARCHES RELATING TO A. Fie. 123. B horizontally on the table, this camera lucida certainly shows the drawing-pencil with greater distinctness than any other —— similar instrument, that of Oberhiuser-Hartnack not ex- Fic. 124 cepted. For very long-sighted persons the two convex glasses | placed below the two smaller << mirrors may be of use, but for l| normal and short-sighted per- sons they are useless, and it is, moreover, better left to each individual to assist his sight by spectacles as required. The cap (with an aperture) over the two mirrors is also well adapted to serve as a guide to direct the eye of the observer, and thus facilitates its use by beginners, who often have a difficulty in finding the image. These advantages are, how- receives the rays from § and reflects them upon a plate of glass s! and thence to the eye, the pencil being seen through the latter (abcd is the fitting which holds s' and s?). There is a subsidiary apparatus formed of two plano-convex lenses | for reducing the amplification. = ht: Oberhauser’s (or Hartnack’s) i= camera is shown in Figs, 123 and 7 i 124. It consists of two tubes A A nh N | == at right angles, a rectangular prism ii ===" being inserted at the point of junction, by which the rays coming = from the object are reflected through = === an eye-piece B fe toa smaller prism ——— a ==>==-— ©, and thence upwards to the eye. HATTA SA fl TTT Pe We Cid ARAN az | ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 681 ever, counterbalanced by considerable defects. The sharpness of the image is impaired by the threefold reflection, which is effected partly by mirrors silvered at the back, and partly by the transparent mirror, the two surfaces of which produce images which of course do not coincide. By using still thinner mirrors this defect might be lessened but not removed entirely. The right and left sides of the object are inverted (though the image is otherwise erect), and this renders it difficult to a most tiresome degree for the microscopist, who is accustomed to the inverted motion of the object, to adjust it, and still more to afterwards correct complicated drawings by the ordinary microscopical image. Employing an _ orthoscopic eye-piece or inverting the drawing arrangements is of no use, as the microscopical image, compared with the drawing projected by the camera, appears in both cases with right and left hand parts interchanged. The camera, moreover, will not bear the application of the blue glass disks supplied with the Oberhiuser instrument for modifying the light, as the image becomes almost invisible. As its character- istic, however, is the relatively great brightness of the surface of the paper, a smoked glass mirror, in place of the plain one 3’, would be the more serviceable arrangement, but the instrument is not constructed so as to allow such a change to be readily made. The combination of lenses for the purpose of reducing the image is, the author thinks, a valuable addition. The insertion of the camera lucida is of course equivalent to lengthening the tube of the Microscope, and the image is strongly magnified, often too much so. It is only to be regretted that when both plano-convex lenses are employed simultaneously, the image, already obscure, becomes still less clear, and in some cases almost invisible. Dr. Cramer also draws attention to the fact, not thought of by Hofmann himself, that his camera lucida combined with the reducing apparatus, when inserted in the tube of the Microscope instead of the eye-piece, will give an image without the objective. The amplification with the two lenses is about four times. He considers that “if Hartnack could prevail upon himself to construct his camera lucida in such a way that in the short arm, or in place of it, a combination of lenses analogous to Hofmann’s were introduced so that an image magnified only four to eight times could be obtained, the value of this instru- ment, already so desirable for the microscepist, would be materially increased.” Dr. Cramer then describes an instrument suggested by himself :— “Those who use the Microscope, especially beginners, are not always in a position to buy a camera lucida. I think, therefore, that I shall be doing many a service by showing how any one who possesses a little mechanical dexterity may make for himself the very serviceable camera lucida shown in Fig. 125. “Tt consists essentially of two somewhat diverging mirrors, one of which, 8, allows the image of the object to be viewed direct through a circular hole made by removing the quicksilver from the under side of the mirror. By the second mirror, §', the rays from the pencil and 682 SUMMARY OF CURRENT RESEARCHES RELATING TO paper, which lies horizontally on the table to the right, are reflected to 8, and thence upwards to the observer’s eye. If the field of view is too bright, the light may be moderated by blue glasses placed in front of the illuminating Fic. 125. mirror. The apparatus is attached by a wire pin to a ring R, made out of strips of paper, and can be readily detached when required. “The ring should be made first, as it has to move with some friction on the upper end of the tube of the Microscope, and must exceed in diameter the upper rim of the eye-piece about 2’. The eye-piece should be removed, and the upper end of the tube used as a mould for making the ring. The outer layers of the ring must be made higher than the inner ones by about the thickness of the upper rim of the eye-piece. This rim will thus fit into a correspond- ing depression in the ring. The aperture for receiving the wire pin is best made last of all, by the repeated insertion of a red-hot needle. This should be done with the eye-piece in place in the ring. After this, two rectangular plates should be cut out of an old mirror, the glass of which must not be too thick, and the coating of quicksilver should be scratched off from a central hole. Then attach by gum two pieces of card of the same shape and size to slightly larger pieces of note paper, and place the mirrors (after making a hole in one of the cards to correspond with that in §) with their backs downwards on the cards. Gum the projecting edges of note paper, turn them up, and press them down over the edges. Then make the trapezoid sides of the apparatus (also out of cardboard), and attach them to larger pieces of note paper so as afterwards to be able to glue them firmly to the backs of the mirrors. Cut two pieces the exact shape of one of the sides out of a cigar box for the purpose of strengthening the side turned towards the observer, which receives the wire pin. A pin of about 1 mm. thickness is quite sufficient. It should be bent twice at right angles, so that its two legs of unequal length are about the thick- ness of one of the two wooden boards apart. The longest leg passes between the card and one of the boards, and the other shorter one between the two boards which’ are to be glued together. Grooves must first be made in the boards corresponding to the thickness of the wire. The direction of these is easily settled by remembering that the pin must be placed exactly in the middle of the half of the ring turned towards the observer. ‘The sides abcd must be in.a horizontal plane, and the lower edge en of the mirror S (parallel to ac) must be exactly on the boundary between the lower and upper halves of the card ring. “ When all has been put together, it is well to increase the firmness ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 683 of the apparatus by pasting on an additional piece of card of the shape bd fg, and all the surfaces except the mirror should be blackened with indian ink. . “Dimensions:—ab and cd, also ah, bi, gk = 30 mm.; bg, df, and the corresponding sides of S = 87 mm. ; the mirror less by the thickness of the card—he, id, and kf (in my apparatus made for Oberhiuser’s eye-piece = 10 mm.) will vary according to the size of the eye-piece. Diameter of the hole in the mirror 8 = 3 mm. _Dis- tance of its upper edge from the left side of the mirror = 19 mm., angle fde = 157°, dce = 36°, cef = 130°, ef d = 37°.” Bausch and Lomb Optical Co.’s Fine Adjustment.* — Fig. 126 represents the original of the fine-adjustment referred to at Vol. I. (1881) p. 110. Two strong parallel blades of finely tempered steel, aa, are securely fastened on one end to the back of case Fic. 126. d, on the other to the arm e, which carries the rack and pinion. 6 shows the micro- meter screw, which is fitted to the upper part of the upright arm c, fis the pinion, g the rack and slide, h the tube. Two screws fasten the adjustment case d to the pillar c. An arm projects from the part e and passes into a recess in the pillar c. The springs support the entire body, and as their tension is upward, the pro- jecting arm bears continually against the micrometer screw b, and it is evident that the distance traversed by the screw involves the same movement of the arm e, and consequently the body. The only points of contact are at the ends of the springs a, a, where they are fastened re- spectively at d and e, and on the micrometer screw, and as in the former there is absolutely no friction, there is no wear; while that which may eventually take place in the latter is taken up by the force of the springs. The points of excellence claimed by the makers for this adjust- ment over all others, are the following :— * From the Company’s Price List, 7th ed., 1882, pp. 4-5 (1 fig.). 684 SUMMARY OF CURRENT RESEARCHES RELATING TO *©1, It moves the entire body. 2. It is extremely sensitive and direct. 3. It has no lateral motion or displacement of the image, while adjusting. 4. It has absolutely no lost motion. 5. It can in no manner deteriorate.’ The “ Professional” Microscope (shown at Fic. 127. Fig. 113, p. 667) has the fine adjustment in the form above described, while in the “ Model” Microscope of the same makers (Fig. 127) a slight variation is made by the bar e being placed below instead of above. Nose-piece for Binocular Prisms.—When the broad gauge (1} in.) screw is used (for low powers of wide angle), it is necessary to provide some means, not merely for the withdrawal of the prisms of the binocular, but for the removal of its fittings so that the end of the tube may be left quite free for the full diameter of the objective. This is perhaps best accomplished by the prism and its fittings being in a separate nose-piece, attached to the tube by a well-made ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 685 bayonet catch, when it can be detached as required. By screwing into the broad-gauge thread, after the binocular fitting is removed, an adapter with Society screw, objectives of wide angle, but not requiring the broad screw, can also be used without their being handicapped by the fitting. This plan, by which there are in fact three distinct arrangements —lst, the broad-gauge screw; 2nd, the Society screw without the binocular ; and 8rd, the Society screw with the binocular—is the one adopted by Messrs. Sidle in the “ Acme No. 2” Microscope.* Homogeneous and Water-immersion Objectives.t—“ Akakia,” replying to an inquiry whether homogeneous-immersion objectives are to be regarded as useful only where apertures greater than the limit for water (1:33 N.A.) are required, says that “experience has demon- strated that all incident pencils from one refracting medium to another of much greater refracting power, beyond the cone 140° in the rarer medium, make unfavourable angles—angles that cannot be effectually dealt with, and this applies the more the greater the difference between the media. For instance, in a strictly dry lens the aperture between the cone 140° in air (*94 N.A.) and 180° (1:0 N.A.) is prac- tically of little use; in a water-immersion lens the cone between 140° in water (1:25 N.A.) and 180° (1°33 N.A.) is likewise of but little service; and equally in a homogeneous-immersion lens the cone between 140° in the immersion fluid (1°43 N.A.) and 180° (1°52 N.A.) is practically useless. Professor Abbe has arrived at the conclusion that the limit of useful aperture is a much lower figure than 1:43 N.A. [Notso. He considers 1°45 the practical limit, ante, p. 472— Ep.] With our present means of construction, however, the lenses which exhibit the finest definition with direct oblique illumination that would utilize 1:25 N.A. are not those lenses of precisely 1°25 N.A., but of higher aperture. It would thus appear that in order to get a well-corrected outer zone of 1:25 N.A., the lens must really have a larger aperture to cope successfully with the difficulties of the marginal aberrations. It should be observed that by the homo- geneous-immersion formula the higher apertures (say those beyond » *94 N.A.) are more successfully corrected, because the path of the rays is more regular, and can thus be more definitely calculated. This is clearly evidenced by the superiority of definition seen with homogeneous-immersion lenses, when, by the conditions of the object and the illumination, the effective aperture is reduced well within the limits that have already been attained by the water-immersion formula: it is then seen that for all apertures greater than 1:0 N.A. the homogeneous-immersion formula is to be preferred. I believe it is now generally accepted among expert manipulators that the water- immersion formula has seen its best days, and the time is not far distant when it will be entirely superseded.” Collar Correction of Objectives,{—Prof. A. Y. Moore considers that collar correction has not received the attention which it deserves, * See also Bulloch’s Congress Microscope, this Journal, iii. (1880) p. 1076, + Engl. Mech., xxxy. (1882) p. 551. t ‘ The Microscope,’ li. (1882) pp. 8-11. Ser, 2.—Vok. II. Fie 686 SUMMARY OF CURRENT RESEARCHES RELATING TO being overlooked entirely among the younger microscopists. As so little has been written on the subject, he gives “a few simple directions. | Every objective has a certain colour with which it shows best, and there is probably no object better adapted to the purpose of deter- mining this colour than a well-marked Podura-scale. .... When a good scale is once obtained, great care should be taken to keep it dry, for when wet it is of no use. Now, by examining this scale with a first-class + or higher power of medium or wide aperture, it will be seen that the ‘exclamation marks’ are more or less coloured. Pay no attention to this at first, but carefully turn the collar back and forth until the marks appear sharpest and smallest. That will be the point of best correction, and now the colour of the markings should be noticed. Having carefully determined the exact tint of best correction, throw the objective a little out of proper adjustment by turning the collar towards open point or zero. ‘This over-corrects it, and at the same time notice the change in colour. The markings seem to expand, becoming hazy and not at all sharp. Now turn the collar towards closed until the point of best correction is passed: here the same thing is seen in regard to expansion and haziness, but a different tint seems to make its appear- ance. By attending very closely to this colour (which is the secondary spectrum), the proper correction can easily be made. I can best illustrate this by the following trial :— I have before me a +; objective. By trial over a Podura-scale I find that when best adjusted the marks appear of a brilliant ruby red (and most of the finest objectives which I have seen show best with this colour); by turning the collar below zero they turn greenish, while, if turned towards closed, they become pink. Hence at the first trial of any such object, should it appear green, the collar should be turned towards closed until the ruby tint appears, and if too pale a red, or pink, the collar should be turned towards zero. By a little practice the microscopist can tell at a glance which way to turn the collar. There are some objects on which a correction cannot be thus made; in such cases the coma must serve as a guide. The edge of a red blood-corpuscle will serve as a good test for practice in this way. By carefully moving the collar back and forth until the edge is sharp and clear, it will be seen that a brisk movement of the fine adjustment causes the edge of the corpuscle to expand, both as it goes beyond the focal point and also within the focal point. If the correction has been made exact, this expansion (coma) is equal both ways, but should the greater expansion be when the object is beyond the focal point, the objective is under-corrected, and the collar should be turned towards zero; but should it be the reverse, that is, the greater expan- sion within the focal point, the objective is over-corrected, and the collar should be moved towards closed.” The author then refers to the deceptive appearances produced by a want of proper correction, such as lines or network instead of dots and points ; and that with homogeneous-immersion objectives without ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 687 correction-collar the draw-tube should be pushed in if the object appears too green, or if too pink drawn out until the ruby tint is obtained, assuming, that is, that the objective corrects in that colour. In the above note we remark that Professor Moore does not specify whether the 5!; objective was dry or immersion. It should also be observed that in testing the colour-corrections of a large-apertured immersion objective on a dry Podura adhering to the cover-glass, it may happen that there is an appreciable film of air between the scale and the surface to which it adheres, in which case the “ruby” tint may be replaced by a deep red colour which cannot be corrected by the adjustment-collar. The objective will then be acting as a badly corrected dry lens. In such a case a scale must be sought that is more closely adherent to the cover-glass. It is a fact well known to opticians that objectives of large aper- ture which are very perfectly achromatized do not yield such sharp definition of a dry Podura-scale as those in which the outstanding colour-aberration is of a moderate ruby tint. The more closely adherent the scale is to the cover-glass, the less red should be the tint; and if by means of the vertical illuminator or equivalent means a scale is chosen which adheres closely, the ruby tint will be less pronounced, and the definition generally more perfect. Measuring Thickness of Cover-glass by Correction Collar.*— Professor C. K. Wead points out that the thickness of a cover-glass “may be found quite closely by means of an objective with correction. Taking the covers used above [| *0058 inch and : 0123 inch], and having focussed on dust or finger marks on the under side, turn the collar till dust on the upper side is in focus; with the thinner glass several trials gave as the reading of the collar 3°:6, 3°:75, &c.; working backwards focussing on the top with the collar at 9°°6 and then on the lower side by the collar the reading was 6°:1 twice, a change of 3°5; mean of seven trials gave 3°:56; similarly with the thicker cover, mean of five trials gave 7°°58. If we assume the change of the collar to be just proportional to the thickness of the glass, since the thin glass is *0058 inch we should have 3°56 : 7°58 :: :0058 : thickness of thick cover: solving we find it to be :01235 inch—a difference of less than +,);5 inch from that found by a Brown and Sharpe’s gauge—a quantity scarcely measurable with this gauge. If one has, then, a single cover-glass whose thickness is known, by a simple proportion the thickness of any other one can be found in a moment. For this particular lens the reading of a collar multiplied by 1-6 will give very closely the thickness in thousandths of an inch. Makers might easily furnish for their lenses the constant multiplier to be used as this 1-6 is; or divide the scale so as to indicate directly the thickness in thousandths of an inch.” Bausch and Lomb Optical Co.’s Glass Stage and Slide- carrier.{—This (Fig. 128, see also Fig. 113) is intended as a sub- stitute for the mechanical stage to a certain extent. It consists of a * ring of the mounting, the diaphragm is made to pass laterally from the centre to the extreme edge of the illuminator, thereby throwing rays of any desired obliquity, between 0 (central illumination) and the extreme possible limit, 1°52 in crown glass. When the diaphragm is at its extreme limit a second slit, at right angles to it, giving the same volume of light, is opened by the further movement of the milled ring, thus utilizing two pencils at right angles. The illumination is said to be amply sufficient with the highest powers, and the fact that it is used with only central illumination of the mirror, will, it is con- sidered, “prove especially valuable to those who do not possess instruments with the modern swinging substage and mirror-bar.” The illuminator is also said to give excellent results when used as non-immersion. A cap with minute aperture (Fig. 131) to facilitate centering, and an adapter (to receive the optical part without the diaphragms and so to give full aperture) accompany it. Gundlach’s Immersion Condenser.*—E. Gundlach discusses this subject, and expresses the opinion that of all the apparatus for pro- viding oblique illumination for large apertures, the Abbe condenser has apparently been the most efficient, and has been generally adopted as the most suitable illuminator for the widest angled objectives, hence it is advisable to inquire whether this form of condenser is capable of doing all that is demanded of it now, or that will be demanded in the near future; and to this inquiry he has given much special study. As the full advantage of a very wide-angled objective cannot be had unless light can be made to pass through any part of its aperture at will, the Abbe condenser would be the best, if it were possible, practically, to increase its angle to correspond with that of the objective; but it can be shown, Mr. Gundlach considers, that it cannot be so increased, and that it cannot approach within 20° or more of 1°52 N.A., as is now, or soon will be, desirable. “Tf the point where the optical axis of the objective cuts the plane of the object be considered the vertex of an angle which has the ex- tended optical axis of the objective for one side, then the other side of the angle extended downward will cut the under side of the slide on which the object is mounted, at a certain distance from the axis, and this distance is proportional to the thickness of the slide. Besides, if the said angle is equal to half the angle of aperture of the objective, * Amer. Mon. Micr. Journ., iii. (1882) pp. 85-7 (1 fig.). 690 SUMMARY OF CURRENT RESEARCHES RELATING TO then this distance is the radius of a circle which the available front of the condenser, or other apparatus, must cover, so that light may enter the objective at the most extreme angle of obliquity. If this distance, which we will call d, be 52, inch, then the available surface of the condenser must be a circle of at least 3 inch in diameter. “ Now, assuming the thickness of the usual object slide to be 5 inch, though this is hardly enough, if the angle of aperture of the objective is given, we may find the distance d, for with the thickness of the slide, ;4, inch, as the cosine, the distance d will be the sine of half the angle of aperture of the objective. If the angle of the aperture of the objective be 120°, or 1:31 N.A. in crown glass of 1:52 refractive index, then the distance d would be 0:144 inch, which, however, will not introduce any special difficulty in the con- struction of an Abbe condenser, as the connecting, or front, surface of the condenser need not be larger in diameter than 0: 288, or a little over J inch. But when we come up to 140° crown-glass angle, or 1:42 N.A., the distance d increases at once to 0°228 inch, and the connecting surface of the condenser must be at least 0-456, or nearly 3 inch in diameter. With so large a front surface, or as it is better expressed, front aperture, the condenser to be fully up to 140° crown glass, will have to be of an equivalent focus of at least inch, which - with 140° in crown glass, will make the back-aperture 1°42 inch, or near 1,%, inch, and in mounting it will be pretty close work to get this inside the substage tube. But let us go a step further and suppose an objective of a crown-glass angle of 160° or 1°49 N.A., which may be expected before long. This angle will increase the distance d to 0:47 inch, and the diameter of the front aperture of the Abbe condenser must be at least 0:94 or 413 inch. Now, as the increase of the angle of aperture of the condenser from 140° to 160° will considerably lessen its working distance, it will have to be con- structed of so much longer equivalent focal distance as to keep the working distance of the slide thickness, of at least 14 inch focus (sic), and even with this it will be hard to get the required working dis- tance. But a condenser of 14 inch equivalent focus and 160° crown- glass angle will require a back-aperture of 3-98 inches. “ Attaching this mammoth condenser to a Microscope having a stage, and consequently all the base parts that support it, on the same scale, we should have an instrument of such proportions as would give the appearance of a derrick, rather than that of a Microscope. “ These examples satisfy us that the Abbe condenser, useful as it is, by no means fully meets all the requirements of oblique illumination, and that practically this illumination cannot very well be made of greater angle than it already has. Hence we have either to find some other suitable means of obtaining still more oblique illumination, or to give up, as useless, the increase of the angle of the object for an increase in performance. “ So it is wise to consider the solution of this problem of illumina- tion before the further improvement of the objective by the increase of angle. In this direction, I desire to submit for consideration the idea of an oblique light reflector represented in Fig. 132. §S represents the ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 691 object-slide; R the proposed reflector. It is a section of a sphere. The upper plane surface is to be brought in contact with the slide by means of a suitable fluid in the usual way. The under surface is concave. The dotted lines show the direction of the light, which Fie. 132. undergoes an inner total reflection at the surface C. Perhaps this reflector will answer for the next limited period; and when even this shall prove to be insufficient, I propose to mount the object on the plane surface of this reflector. In this way the theoretical limit would be reached, and opticians can go on constructing objectives that will take and utilize the oblique light of this reflector.” [It is unnecessary to provide for any apertures in excess of 1°45; and the assumption of 44, inch for the thickness of the object-slide is unnecessarily large, +4, inch being the average. With these alterations the maximum figures given by Mr. Gundlach (+3 inch for the front lens and 3°98 inch for the back lens) would be reduced.—Eb. | Symmetrical Ilumination.*—Mr. Gundlach also desires “ to call attention to another idea, which, if carried out properly, may be of advantage. I thought that a good result would be obtained if the object should be obliquely illuminated symmetrically, i.e. from diametrically opposite sides at the same time, with equal obliquity, intensity, and quantity, rather than from one side only; for the secondary spectrum, with the unavoidable slight chromatic over-cor- rection of the outer part of the objective, produces a more or less visible and disturbing spectrum, which will be neutralized in the pro- posed way. I have tried this, and after some difficulty I think I suc- ceeded in obtaining a result in resolving which I could not get in the usual way. From my limited experience in this matter I can say, however, that this symmetrical illumination requires a very delicate fine adjustment; the one I used gives a motion of only 54, of an inch at a full turn of the screw; for apparently the two images, projected separately by the illumination from each side, do not move in the direction of the optical axis when the screw is turned, but they move each toward the side from which they are projected, and it requires great precision to get them to coincide perfectly. Further desirable experimenting in this, for which I do not deem myself competent, I feel obliged to leave to experienced and skilful microscopists, and I * Amer. Mon. Micr. Journ., iii. (1882) p. 88. 692 SUMMARY OF CURRENT RESEARCHES RELATING TO shall be grateful if informed of the results of any experiments tried by them.” Gundlach’s Substage Refractor.*—This apparatus, intended for measuring the aperture angle of wide-angled objectives, consists of a small crown-glass cube, with sides about 3, inch. One face is opaque, the one opposite and the two others opposite each other, polished. The cube is made to adhere, by means of a suitable homogeneous medium, to the front surface of the objective by the polished surface opposite the opaque side. Then a ray of light must enter each of the polished side surfaces in the plane described by the optical axis of the objective and a line perpendicular to those polished surfaces, and at such angular inclination to the optical axis that it will pass through the objective close at the edge of its aperture, and emerge from it in the direction of the optical axis. The angle described by the refracted rays inside the crown-glass cube, is equal to the crown-glass aperture angle of the objective, and is :— a cos 2 = COS —s r a being half the angle described by the two rays before entering the cube, r the refractive index of the crown glass, and n the crown-glass angle of the objective. Silvered Convex Lenses v. Concave Mirrors.;—Mr. C. V. Boys points out that convex lenses silvered at the back make excellent and easily-constructed concave mirrors. Since both surfaces conduce to bring the light to a focus flatter curves may be used than are neces- sary for a plain concave reflector of the same focal length; also since the two surfaces are not parallel false images are not produced, so that the advantage of glass silvered at the back remains without the usual disadvantage. Binocular Vision in the Microscope.t— Professor C. Cramer, in connection with a description of Prazmowski’s binocular eye-piece, discusses the conditions of stereoscopic binocular vision in the Micro- scope. In particular he points out the error of the views of Nageli and Schwendener that the depth of the field of view is of only secon- dary importance to the stereoscopic effect, a view which they attempt to support by the fact that in the ordinary stereoscope the two pictures are perfectly plane, but yet produce the impression of solidity. These pictures require, however, to be taken from different points of view, or no stereoscopic effect whatever will be produced. Microphoto- graphs of statuary, &c., do not appear to be more solid when observed with a stereoscopic Binocular than with a single eye. The author further describes the appearances, by the left- and right-hand halves of an objective respectively, of oil-globules and air-bubbles in water by transmitted light and a small cylindrical opaque object, as establishing to what in fact the stereoscopic effect is due. He also * Amer. Mon. Micr. Journ., iii. (1882) pp. 142-3 (1 fig.). + Phil. Mag., 1882, { Vierteljahrsschr. Naturf. Gesell. Ziirich, xxiv. (1879) pp. 95-106. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 693 discusses the effect of observing the two different images with a single eye (when each point of the object is seen in one direction only), and the difficulties attending the recognition of the respective distances of parts of an object with one eye. With ¢rue solid vision with two eyes they must constantly be accommodated according as we desire to see the nearer, central, or more remote parts of the object. With apparent stereoscopic vision this is not, however, necessary. Finally, the author expresses his opinion as to the value of bino- culars as follows :—“ For the solution of natural problems the author cannot expect much of the stereoscopic Microscope since the sharpness of the image leaves much to be desired.* Its use for instruction is, moreover, rendered very difficult in that each observer must regulate not only the focus but also the lateral distance of the eye-pieces. Nevertheless, for microscopical objects of complicated form the instru- ment may here and there prove useful.” Miniatured Images.—In the President’s Address (ante, p. 158) a brief reference is made to the unsatisfactory character of experiments made on miniatured images—spider-lines, for instance, “ miniatured to the fourteenth part of the hundred-thousandth of an inch.” The illusory character of all conclusions on the subject of microscopical vision, which are based on the observation of miniatured images, is demonstrated by the following discussion, which we extract from some notes on the subject by Professor Abbe. Fia. 133. Let O (Fig. 183) be an object—a grating or wire gauze, or spider- line, Q its miniature image, projected by means of an objective S, = the objective of the Microscope by which this miniature image is observed, and P the re-enlarged image which is finally seen through the eye- piece.- The linear aperture of the objective = may be denoted by a; the corresponding aperture-angle by w; the angle of convergence of the delineating pencils at the image P by v; the angle of divergence of the pencils admitted from O by u; the distance of O from S by d, and the distance of the final image from = by 4 (these distances being measured from the posterior principal foci of the two objectives which will practically be very near to the back lenses), and f and ¢ the equivalent focal lengths of S and = respectively. All the conditions of the observation are now strictly defined. * In the particular case, on account of the interposition of the prism and additional eye-piece combination. 694. SUMMARY OF CURRENT RESEARCHES RELATING TO Now what is claimed is, that if the spider-line at O is ;5455 inch in breadth, and the objective S diminishes by 100 diameters, we should have at Q a miniature image of ygodoo7n inch, and that this is depicted by the objective >. This is, however, pure hypothesis, without a shadow of proof that the observation of miniatured i images is the same thing as that of real minute objects.* The only fact is, that the observer sees the object - as it is delineated by the composite objective S + = at P. For demonstrating the fallacy involved in the assumptions in question it is not necessary to concern ourselves with any theory of microscopical vision—it is sufficient to rely on the ordinary principles of geometrical optics.t In the first place it is readily shown that the appearance of the supposed miniature—as it is actually seen through the Microscope— has no essential connection with that miniature, the image at P, which is actually and only seen, not even requiring the existence of any miniature, so that the conditions of visibility of things are discussed which need not even exist at all. Suppose the objective S under-corrected and = over-corrected in a corresponding degree—the aberrations of both systems just balancing one another—the object at O will be visible at P with the same distinct- ness as if S and = were strictly corrected ; for the total system (S + 3) is so corrected. Now it is obvious that under the above assumption (antagonistic correction-defects in the two systems) no image of very minute dimensions can be depicted at Q at all, where we should only have large circles of confusion. It need hardly be said that it is an obvious fallacy to infer anything concerning the existence or operation of a given phenomenon from observations which would not be altered in the least degree if that phenomenon did not exist at all. The true signification of the observations in question is obtained by determining the optical character of the composite system (S + 2). This can be done by the following formule, which give respectively (a) the focal length, (b) the amplification, and (c) the aperture angle, by which three things the action of every optical system is perfectly determined. If two systems are identical in all these respects (and * Whether a real (isolated) object, such as a fine line (bright or dark) of sa0e000 ch is visible or not visible through a given objective is only a question of light, of sensitiveness of the observer’s retina, and of good correction of the objective, just as in telescopic vision a single star is always visible, however small its visual angle, provided it is sufficiently bright, but a double star requires a certain minimum aperture of the telescope depending on the angular distance apart of the stars. t On the principles of the Abbe theory of microscopical vision the matter would stand thus:—If there were at O a coarse object of say zo inch in diameter, the mLnNe image would in fact be approximately the ;3,; part in diameter, i.e. 55 inch. But this is not the case with objects and images of such minute dimensions as above referred to, the miniature of the spider-line, if it could for instance be photographed (the system § being absolutely free from aberrations) would be found to be a rather broad band not less in diameter than half the wave-length of light. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 695 equaliy well corrected) they must always give the same image of the same object. With the notation indicated above, the equivalent focal length F of the total system (S + =) is Tf Weak ' Bi. gu a hele the linear amplification N (of the ultimate image at P), Le fe kal ie ) j and the aperture angle wu of the total system (resulting from the linear aperture a of the objective =), Ones a\. u=a : - v (where » = 2); therefore LG =e o To take an example: let S be an } inch and 3a ,}, objective, d = 400 mm.,§ = 200 mm.,a = 3 mm., f = 3mm.,¢ = 2 mm.—then we have 1 300 1_, 200 1 ty8 OG ey F ~ 200 400 * 300 200 ~ 800 * 300 ~ 2400 4 HN ee = 141 mm. (= 53 inches approximately) _ 200 300 3 ~ 400 200.4 The ultimate image at P is therefore a slightly (3:4) diminished image of O. va B30 9 400 200 880 which is an aperture angle of about 2°. Thus the simple matter of fact is that if the miniature of O is observed at P we observe the real object O by means of a very low- power objective (54 inches) of very low aperture (3°) under a very low linear amplification, and nothing more is shown therefore by the observation but this, that spider-lines and similar things can be seen through very low-power objectives, which nobody will doubt. The formule for F, N, and u show that the focal length of the actually effective system, the ultimate amplification, and the aperture angle do not depend on any other elements except (1) the distances d and 6 of the object and the ultimate image, (2) the ratio of the focal lengths of the objectives S and 3, and the latter in addition (3) on the linear aperture of the objective. Now F, N, and u, as has been said, comprise all elements of the effective system (S + 3) which can possibly have any influence on its performance (spherical correction of 696 SUMMARY OF CURRENT RESEARCHES RELATING TO the total system being supposed), and the same values of F’, N, and u will therefore indicate the same effect always. Consequently we shall obtain exactly the same results whether we apply an 3-inch and ;!;-inch, or instead of these any two low-power objectives with the same ratio of the powers (2 : 3), for instance a 2-inch and a 3-inch or (the simplest case) a single lens of 54 inches, always preserving the distances d = 400, 5 = 200 and the narrow diaphragm correspond- ing to the linear aperture of the +, (3 mm.). These considerations show the illusory character of the experi- ments in question as all the observations would have had the same result even if objectives had been applied not of the high powers actually used but of low power or even consisting of a single lens, that is under circumstances in which either no miniature at all is formed, or none of the minute dimensions claimed. Nothing can be inferred from such experiments in regard to high-power vision, at any rate. They are in fact, experiments on low-power vision, and under artificially and unnecessarily complicated conditions, a complicated system, E -+ 3, composed of a number of lenses being employed for obtaining no other effects than can be produced by a single lens of small aperture. Black Annuli and Lines of Spherules and Threads.—In the same Address * is a reference to the attempts made to demonstrate the defective vision of objects under objectives with wide apertures, by means of glass spherules and threads, the characteristic black lines seen when low apertures are used nearly disappearing when the aperture is increased. It is true that transparent spherules and threads of 0:1 inch in diameter, or many times greater than a wave-length, behave accord- ing to the laws of refraction, and show annuli, &c., which are very strong and black with low apertures, but are much less marked with wide ones, but very minute spherules or filaments of the same shape, which are only a wave-length or less in diameter, do not show the black annuli and lines even with the narrowest apertures. 'They appear either uniformly illuminated or with a gradation of light which has not the least similarity to the annuli, &c., of the coarser refracting spheres or cylinders, and this for the reason that such minute objects do not act as refracting bodies but only by the retardation of the transmitted waves. This shows the essential fallacy involved in the experiments in question. That the black annuli of the coarse objects become in- distinct with wide apertures proves only that wide apertures are not the proper means for examining such coarse objects. ‘This, however, requires no proof nowadays, when it is well recognized that wide apertures should not be applied for objects which are completely depicted by low ones. The notion that minute objects which require high powers in order to be seen are better seen with low apertures, is a conclusion derived not from direct observation, but simply inferred from the supposed * pp. 158-9. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 697 analogy of the phenomena presented by large objects, and with the assumption that the same phenomena must hold good in the other case also.* Curiosities of Microscopical Literature.—One would hardly have expected to find such a paragraph as the following in a book pub- lished in London in 1881, even although written “without assum- ing the possession on the part of the reader of other attainments than those possessed by the average schoolboy or schoolgirl” :—“ In the * same year (1824) Tulley, of London, succeeded in constructing for “the first time in England an object-glass of 3 lenses. Sir John “ Herschel, Professor Airy, and Professor Barlow [no mention of “ Lister !] furnished valuable contributions to the theory of the “ achromatic object-glass. More recently a suggestion of Sir David ‘“‘ Brewster’s has been carried out, by the construction of lenses of “diamond. By these and other. modern improvements, especially in * the mode of illuminating the objects, investigations are now carried “into structures so minute that magnifying powers of 2000 or 3000 “ diameters have to be used” ! + The suggestion of diamond lenses was abandoned more than fifty years ago,{ and none of the present generation of Microscopists have ever had an opportunity of testing the “improvement” which it is suggested the diamond has been to microscopical investigation. When will popular writers get to understand that neither the size nor the magnifying power of a Microscope forms the standard of its efficiency, and that amplifications of 2000 or 3000 diameters could be obtained without any difficulty half a century ago, when, notwith- standing, much less was visible than can now be seen with a tenth of the power. In a subsequent paragraph it is stated that the “ binocular form of construction, though attempted very long ago, was not success- fully carried out till 1851.” * Tt must also be borne in mind that it is impossible to make reliable observations as to the relative performance of objectives with different apertures, unless the fact of their perfect correction is ascertained independently of the observa- tions in question, that is on objects the correct appearance of which is not dubious or hypothetical, as for instance, the outlines of thin silver films. Again, it is out of the question in such observations to make arbitrary changes in the conditions under which the objective acts, as shortening and lengthening the tube, interposing other lenses between the objective and the eye- piece, using the objective with immersion fluids for which it was not con- structed, &c. As wide apertures allow of much greater aberration than low ones, it may happen that the former, if the correction is not very carefully made, will show less than a low aperture, even if this is also badly corrected, because the relative deterioration of the image is not so great. + ‘A Popular History of Science,’ by R. Routledge (8vo, London, 1881) p. 515. t Dr. Goring suggested diamond lenses to A. Pritchard in 1824, and he made one in the same year (see Sir D. Brewster’s ‘ Treatise on the Microscope,’ 1837, pp- 13-21). Sir D. Brewster’s reference to diamond lenses will be found in ‘Treatise on New Philosophical Instruments,’ 1813, pp. 402-10; and ‘ Treatise on Optical Instruments,’ 1832, p. 39. 698 SUMMARY OF CURRENT RESEARCHES RELATING TO Assr’s Fluid for Homogeneous-Immersion Objectives. [Ante, p. 551.] Bull. Soc. Belg. Micr., VIL. (1882) pp. elvi.—vii. “ Axakta.”—Abbe’s Apertometer. [Describes his mode of use. Also replies to question of “ Antares” as to whether homogeneous-immersion objectives are useful only where apertures greater than 1°33 are required. Supra, p. 6895.] Engl. Mech., XX XV. (1882) p. 551. American Society of Microscopists. [Note as to the prospects of the Elmira Meeting. | Amer, Mon. Micr. Journ., 11. (1882) pp. 135-6. BizzozEro, G.—Manuale di Microscopia clinica. (Manual of Clinical Microscopy.) 2nd ed. 8vo, Milano, 1882, xii. and 246 pp. (44 figs. and 7 pls.). BuiackuHam, G. E.—Presidential Report and Address (The Evolution of the Modern Microscope) to the Elmira Meeting of the American Society of Micro- scopists. é [Brief abstracts with omissions. The Report contains recommendations to re-appoint the Committee on eye-pieces, and that (a@ propos of the Griffith and Stowell prizes) the whole subject of giving prizes be taken up, and the fixed policy of the Society in regard thereto be decided upon and announced. “It will require careful consideration, as there is much to be said both for and against the practice.” The Address traces the history of the Microscope from the end of the sixteenth century to the present time.) Amer. Mon. Micr. Journ., IIL. (1882) pp. 170-3. Brappury, W.—The Achromatic Object-glass, VII.—X. Engl. Mech., XXXYV. (1882) pp. 489-90, 537-8 ; XXXVI. (1882) pp. 26-8, 78-80. Brepisson, A. p—.—See Chevalier, A. Brewer, W. H.—Apparent Size of Magnified Objects. [Abstract of paper presented in the Sections of Histology and Microscopy at the Montreal Meeting of the American Association for the Advance- ment of Science. Post.) Amer. Mon. Micr. Journ., Til. (1882) p. 161. Brittain, T.—The Beginnings of Microscopic Study. [Several corrections necessary. (1) Baker (and not Trembley) is credited with the first demonstration of the vitality of Hydra when cut to pieces, while (2) the discovery of achromatism and the manufacture of achromatic lenses and the revolution which they caused in Microscopy has been lost sight of, the position of the Microscope in 1830 being thus dealt with :—“ About 1830 the mechanism and general arrangements of the materials employed began to show a great advance upon the older instruments, but it was in the lenses that the chief improvements were manifest, and principally in the higher powers. The lower powers, composed of a single lens, remained much as before, while the improvements in the higher powers were carried on to a wonderful state of perfection. The provoking refraction which interfered with the definition of an object when seen with a high power is now got rid of, and what was obscure and doubtful before is no longer so, but becomes a matter of demonstration.” } Field Naturalist, I. (1882) pp. 80-1. Carpenter, W. B.—Address on the Practical and Theoretical Results in the History of the Microscope. [Abstract of Address to the Section of Microscopy at the Montreal Meet- ing of the A.A.A.S. Relates mainly to the relative value of objectives of small and large aperture. | Amer, Mon. Micr. Journ., III. (1882) pp. 161-3. Cuevatier. A.—L’Etudiant micrographe, traité théorique et pratique du Microscope et des préparations. 3° édition, augmentée des applications 4 étude de Vanatomie, de la botanique et de l’histologie, par MM. Alph. de Brébisson, H. Van ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 699 Heurck, G. Pouchet. (The Micrographical Student, theoretical and practical treatise on the Microscope and preparations. 3rd ed., with additions on its applications to the study of anatomy, botany, and histology.) xvi. and 591 pp. Portrait, 179 figs., and 7 pls. 8vo, Paris, 1882. Crisp, F.—Notes sur ]’Ouverture, la vision microscopique et la valeur des objectifs & immersion a grand angle. (Notes on Aperture, Microscopical Vision, and the value of wide-angled Immersion Objectives)—contd. (Transl. of paper, ante, I. (1881) pp. 303-60. ] Journ. de Microgr., VI. (1882) pp. 362-5 (3 figs.), 417-8 (8 figs.). Davis, G. E.—Prof. Abbe’s Paper on the Relation of Aperture and Power in the Microscope. North, Microscopist, II. (1882) pp. 211-2. 5 - A Plea for Wide Apertures. [“ A reply to Prof. Abbe’s paper ‘On the Relation of Aperture and Power in the Microscope.’ ” } North. Microscopist, U1. (1882) pp. 229-38 (1 pl. of 4 photos.). How to Found a Local Microscopical Society. North. Microscopist, 11. (1882) pp. 212-6. DrepeL, L.—Das Mikroskop und seine Anwendung, ler Theil. Handbuch der Allgemeinen Mikroskopie, le Abtheilung. 2nd ed., 8vo, Braunschweig, 1882, viii. and 336 pp., 189 figs. a » Die Correctionsfassung bei Objectiv-Systemen fiir homogene Immersion. Zeitschr. f. Instrumentenk., II, (1882) pp. 269-74. Dyck, F. C. Van.—Significant Angle. [Objections to the paper of the Hon. J. D. Cox, ante, p. 422.] Amer. Mon. Micr, Journ,, LLL. (1882) pp. 154-5. Encetmann, T. W.—Ueber Sauerstoffausscheidung von Pflanzenzellen im Mikrospectrum, (On the disengagement of oxygen by vegetable cells in the Microspectrum.) (Contains a description of the Microspectroscopic Apparatus, ante p. 564, and supra p. 661.] Bot. Ztg., XL. (1882) pp. 419-26 (1 fig.). Fresco, M.—Beleuchtungsvorrichtung zum Mikroskopiren bei kiinstlichen Licht. (illuminating Apparatus for Microscopical Observations by Artificial Light.) [The numerous lamps of often complicated structure are superfluous for histologists or for other purposes than resolving test objects. Light modifiers of tinted glass are, however, useful, and can be arranged to be conveniently placed in the carrier-plate of the Abbe condenser. Sep. repr. SL. Phys.-Med, Gesell, Wiirzburg, 1882, 2 pp. Grunow’s (J.) New Microscope. [No speciality in form.] Amer, Mon. Micr. Journ., III. (1882) pp. 146-7 (1 fig.). GuUNDLACH’s (E.) Substage Refractor. [For measuring the apertures of wide-angled objectives. Supra, p. 692.] Amer. Mon, Micr. Journ., III. (1882) pp. 142-3 (1 fig.). GunpLacu, E.—A Simple Method of determining the Angle of Aperture of Immersion Objectives. [Apparently the same as the preceding. ] Amer. Mon, Micr. Journ., III. (1882) p. 176. ” ” GuNDLAOH’s =1,-in. objective. [Notices its intended manufacture. “ We hope to live long enough to see it.” | Amer, Mon. Mier. Journ., III. (1882) p. 158, Hevrcr, H. Van.—See Chevalier, A. Hircncock, R.—Physicians and Microscopists. [Rejoinder to the ‘ Medical Register’ as to their comments on the original note, ante, p. 423.] Amer. Mon. Micr, Journ., III. (1882) p. 136, 700 SUMMARY OF CURRENT RESEARCHES RELATING TO Hitcucock, R.—Uniformity in Oculars. [The only way to secure uniformity is to convince purchasers of its importance.” | Amer. Mon. Mier, Journ., III. (1882) pp. 155-6. * 2 Table of Numerical Apertures. [Brief additional remarks. | Amer, Mon. Micr. Journ., III. (1882) p. 156. M., W. H.—Schrauer’s Microscope. [Travelling instrument with removable base, not requiring a box, but to be “‘ laid between other goods in one trunk.’’] Amer, Mon. Micr. Journ., III. (1882) pp. 158-9. MackeEnziz, J.—Two forms of gas lamp specially for use with the Microscope. (Exhibited.) [No deseription. ] Journ. Quek. Mier, Club, I. (1882) p. 105. Marrens, A.—Ueber die hygienische Ausstellung in Berlin. (On the Hygienic Exhibition in Berlin.) [Records the fact of the exhibition of various Microscopes, apparatus, and preparations. | Central-Ztg. f. Optik u. Mech., (11. (1882) pp. 145-6. ‘Northern Microscopist’ Verification Department (contd.). North. Microscopist, 11. (1882) pp. 239-40. Numerical Aperture.and Micrometric Tables. [From pp. 7 and 8 of the Wrapper of this Journal. ] Amer. Mon. Micr. Journ., III. 1882) p. 134. PELLETAN, J.—Microscope “‘ Continental ” (“‘ Continental ” Microscope). [p. 356: Announcement that it will be ready for delivery on 1st September. —‘“It represents a ‘Centennial’ of Zentmayer or a ‘Congress’ of Bulloch constructed 4 ’ Européenne.” pp. 406-7: Descrip- tion of the instrument. ] Journ. de Microgr., V1. (1882) pp. 356, 406-7 (1 phot.). PINKERNELLE, W.—Apparat zur Erleichterung der Mikroskopischen Unter- suchung von Flissigkeiten. (Apparatus for facilitating the microscopical observation of fluids.) [Abstract of German Patent, No. 18,071, 31st May, 1881. Simply a slide made of two glass plates cemented together with a channel between them. A tube connected with one end dips into an open vessel with the fluid to be examined, and one connected with the other passes through the cork of aclosed receiver, which is also pierced by a second tube ending in an indiarubber ball. A stop-cock at each end of the slide regulates the flow.—Also suggestions for simplifying it by substi- tuting a long tube for the receiver so as to act as a siphon. | Central-Ztg. f. Optik u. Mech., III. (1882) p. 155 (1 fig.). Povucuet, G.—See Chevalier, A. President’s Address [Abstract of, concld.]. Amer. Mon. Micr. Journ., III. (1882) pp. 128-32. “ Prismatique.”—Object-glass working, I. [Practical directions. } Engl. Mech,, XXXVI. (1882) p. 54. Royston-Picotr, G. W.—Microscopes and Microscopy. [Lecture to the ‘ Eastbourne Young Men’s Christian Association.’ ] ; Engl. Mech., XXXV. (1882) pp. 231-2. Standard Gauges for Eye-pieces and Substages. [Note on the Committee’s report, ante, p. 595—“ it is to be hoped that for the future eye-pieces will only be made of the specified sizes; the inconvenience attending the parts of various instruments not being interchangeable is very great, and might in the course of a few years disappear if all new instruments were made to the standard sizes.” ] Journ, of Sci., 1V. (1882) pp. 502-3. STEINHEIL’s Achromatic Eye-pieces. This Journal, II, (1882) p. 551 (2 figs.), Engl. Mech., XXXV. (1882) p. 570 (2 figs.). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 701 Srrorsett, O.—Eine verbesserte Vorrichtung mikroskopische Beobachtungen unter dem Einfluss elektrischer Schlige anzustellen. (An improved arrangement fur microscopical observations under the influence of el ctrical shocks.) [Post.] Zeitsch. f. Instrumentenk., IL. (1882) pp. 274-5 (1 fig.). Treskow, H.—Fiihrung am Objectivtische des Mikroskops nebst Compres- sorium. (Carrier to the Stage of the Microscope with Compressorium.) German Patent, No. 13,399, 9th September, 1880, 2 figs. (1 pl.). Vorce, C. M.—[Note as to easy and quick resolution of Amphipleura pellucida in balsam by Bausch and Lomb 2-inch and 2-inch objectives, with mirror central, sunlight, aud no condenser. | Amer, Mon. Micr. Journ., IL. (1882) p. 137. Warp, R. H.—The August Meetings. [Elmira Meeting of the American Society of Microscopists, and Montreal Meeting of the Amer. Assoc. Adv. Sci—at the latter the new section of histology and microscopy will meet for the first time. ] Amer. Natural., X V1. (1882) p. 691. “- Eye Protectors. [Description and figure of Pennock’s, I. (1881) p. 518, and description of Hall’s, supra, p. 678.] Amer. Natural., XVI. (1882) pp. 691-2 (1 fig.). Wricut, L.—Light, a course of experimental Optics chiefly with the Lantern. [Contains an Appendix to Chap. IX. on ‘‘ Diffraction in the Microscope,” pp. 200-7, 17 figs.] 8yvo, London, 1882, xxiv. and 367 pp. (190 figs. and 8 pls.). 8. Collecting, Mounting and Examining Objects, &c. Preservative Fluids for Animal and Vegetable Tissues, and Methods of Preservation.*—Many years ago, Professor F. Pacini commenced to make microscopical preparations with a view of pre- serving types of different elements of tissues, both normal and patho- logical, and experimented largely with aqueous solutions of different substances in variable proportions; then, having put up a large number of preparations in these solutions, he allowed some years to elapse in order to see which had best resisted the effects of time. Many, of course, perished; but those which are preserved serve to indicate the best methods to employ. Professor Pacini does not deal with the well-known methods of preserving, by means of Canada balsam or glycerine, microscopical preparations of hard, dry, or indurated parts, merely observing that tissues, when they have been dried or indurated to obtain sections, have lost their water of organisation, and are not suited to give an exact idea of their minute structure; it is necessary that they should be pre- served in an aqueous medium of low density, in order that they may present as natural an aspect as possible. Very thin sections of tissues, when preserved in so dense a medium as Canada balsam or glycerine, become transparent; it is then necessary to stain them in order to render them visible, and whilst they are then certainly more pretty to look at, they are not natural. * Journ. de Microgr., iv. (1880) pp. 136, 191, and 235. Ser. 2.—Vor. II. 3B 702 SUMMARY OF CURRENT RESEARCHES RELATING TO The fluids themselves, whose use the author describes, are already known; the new matter in his present communication is the account of the modes in which he finds they can be most advantageously used. Bichloride of mercury, or corrosive sublimate, is the principal basis of the solutions. Combining with the histological elements, both animal and vegetable, it renders them insoluble, so that they can be preserved indefinitely in an aqueous medium. But, as the bichloride of mercury coagulates and precipitates the albuminous matter that exists in the interstitial fluids of the tissues, to prevent this coagulation salt is associated with it for certain preparations, and acetic acid for others, and in more or less considerable quantities, according to the effects to be obtained. Parts. I. Bichloride of mercury .. .. «1 «2 «2 Distilled water Pen eots cor. oo, AUD IJ. Bichloride of mercury .. Sa tak ke eee 1 (Glommmnoin Sel} 55 1 on co 50 on 0) 2 Distilled water Sean anes ca | o-- co AAD ES Bichlorid ekofemercuiye- na eclen- -ael ene mner 1 (Clormnnneyn S008 “Bo G0 00 bo 60 50 one 4 Distilled water em MONemr ay too ay. PAD Ve Bichlorideyotimencunysge alse 1 PNGEBIG EGG ear enBMONios Mead Gos BO) 60. oc 2 Distilled water =. 2.2 «2 Ge. eee No. I. is of limited use, but will preserve indefinitely all histo- logical substances, both animal and vegetable, which are solid and non-albuminous, for hollow substances either swell or become too opaque by the coagulation of the albumen. It can, however, generally be substituted for the other solutions when it is desirable to entirely remove the salt or acetic acid from the solution in which any given preparation has been placed. No. II. may be generally employed for all tissues both cellular and fibrous, animal or vegetable, provided they are sufficiently dissociated in sections of extreme thinness, because they become somewhat opaque, regaining, however, in time a certain transparency. It is especially useful for the blood-corpuscles of cold-blooded animals having a less density than III. No. III. serves specially for the blood-corpuscles of warm-blooded animals. No. IV. serves best for the nuclei of animal tissues, but it swells up the fibres and distorts the forms of the cells. Still, in certain cases it is very useful, and it preserves the white blood-corpuscles admirably. All the solutions should be employed in sufficiently large quan- tities, and the specimen kept in it for 4-5 days or longer, in order that it may have time to take up a sufficient quantity of the bichloride of mercury before being finally closed up. ZOOLOGY AND BOTANY, MICROSCOPY; ETC. | 703 The use of metallic instruments is to be avoided, because, being attacked by the bichloride of mercury, they give rise to cloudy pre- cipitates, which render the prepared objects thick. Sections should be cut before plunging them in the solution, and when it is necessary to tease out the elements of a tissue it should be done with porcupine quills or pointed goose-quills. If it is wished to preserve red blood-corpuscles, the blood must be diluted with at least 50 to 100 times its volume of solution II. (or - No. III., see above); this is decanted after the lapse of 24 hours, and changed in the same way three or four times. White blood-corpuscles may be isolated by destroying the red ones; this end is attained by the use of solution IV., by means of the acetic acid contained in it. It must be applied for 48 hours in the proportion of from 50 to 100 times the volume of the blood, and must, asin the former case, be changed three or four times. If transferred to solution IJ., the leucocytes gradually regain their original form. Spermatie fluid is preserved in solution II. The liquid must first be stirred round with a glass rod to prevent the elements adhering. Epithelia are examined in the same solution after the parts which support them have remained some days in the solution, spread out, if necessary, on sheets of guttapercha with cactus thorns. Blood-vessels may be beautifully injected naturally by putting the tissues which contain them into solution II. or III. for a con- siderable time (foetus eyes intended to show the vessels of the pupillar membrane should be treated thus for 20 days). Nerve-fibres may be studied advantageously in the cranial and intra-ocular nerves with their comparatively thin medullary sheaths. Muscular fibres are best examined in the muscles of Petromyzon after a treatment of several days with solution IT. If it is desired to collect Infusoria or other very small organisms, animal or vegetable, particularly when they are in movement and scat- tered through a large quantity of water, a tolerably large glass vessel (in order to collect a sufficient quantity) should be filled with the water, and a little of the solution No. If. added. All the Infusoria being killed by the bichloride of mercury, they fall slowly (in three or four days) to the bottom of the vessel, the more slowly as they are smalier. The greater part of the liquid is then to be decanted by a siphon and replaced by some of the solution, which should be changed three or four times. The Infusoria can then be preserved in a bottle or mounted. Preparing Sections of Axis-cylinder.— For extensive lengths of axis-cylinder G. Bufelius* proceeds as follows -—Fragments of nerves of the dog or rabbit are laid for 24 hours in Miiller’s fluid. They are then transferred to an aqueous solution of corrosive sub- limate (*5 per cent.) in which they remain several days, the liquid being constantly changed, until the solution undergoes no further alteration. The tissue is then teased and treated with dilute picro- : ‘Lo Sperimentale, 1880, Nov. Cf. Jahresber. Virchow and Hirsch for 1880, p. 22. 3 BQ 704 SUMMARY OF CURRENT RESEARCHES RELATING TO carmine. Finally 33 per cent. alcohol, and then absolute alcohol, are applied, and the specimens mounted in dammar. Mounting Gizzards of Insects.*—Dr. T. J. Sturt was formerly content to pull off the head of a cricket, drag with it the stomach, and attached to it the gizzard or organ containing the pyloric teeth, skin off the muscular coat with the thumbnail, cut off any portion of intestine, and then mount. This plan, however, missed many interesting points in the stomach and gullet, and he now prefers to kill with a drop of benzine, cut off the extreme tail, pull off the head, cut off the whole intestine, and put it in a 1 oz. phial with 5 or 10 drops of liquid potash. After it has stood about half-an-hour, partly fill with water and shake it well to detach the muscular coat and trachee; then slit it up, wash and adjust on a slide. Drain away any moisture, apply a drop of carbolic acid, and place on the thin glass. After a few minutes this will absorb all moisture, and render it quite transparent. If it does not, put a drop of acid at the edge and tilt the slide to drive off the first acid; then put a little balsam on the edge, tilt the slide, warming it to render the balsam more limpid, and it will gradually take the place of the acid, the lines of demarcation between the two being distinctly visible. Preparing Tape-worms.t—Dr. G. Riehm recommends the follow- ing treatment of specimens. To prevent contraction at death, he cleans the living cestode with a brush, and holds it in the hand until it has extended itself under the action of the warmth, and then rolls it upon a glass tube and plunges the whole into spirit; undue adhesion to the glass is remedied by soaking in water. Such specimens are well adapted for mounting under pressure; they may be stained with alum-carmine or with hematoxylin ; if with the latter, the specimen should be treated with acetic acid for a minute after staining and then washed in ammonia to remove excess of colour. For minute investigation, sections made parallel to the flat surfaces are preferable. To prevent the last sections breaking out of the imbedding mass, this should be made of equal parts of paraffin and white wax with the addition of one or two drops of Canada balsam dissolved in turpentine for each gramme of the mixture. The razor should be wetted with benzine, care being taken not to moisten ‘the object itself too much with the benzine. To secure having the sections cut in the right place, the specimen is soaked in turpentine, placed in a watch-glass of imbedding mass kept liquid by heat, and left there until seen by its transparency to be thoroughly penetrated; some of the mass is then removed with a hot instrument and placed on a slide and pressed out, the specimen is placed on the stage of the microtome and the slide with its paraffin is placed on it; when cool the slide may be removed, leaving the specimen imbedded in a strictly horizontal position. The excretory vessels are injected with * Engl. Mech., xxxv. (1882) p. 282. + Zeitschr. Ges. Naturwiss., vi. (1881) pp. 547-51. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 705 Berlin blue by simple insertion of the syringe; if the animal is moving actively the injection runs forward with difficulty and in any case the neck and head require manipulating with the finger or a wet brush, in order to drive the injection through the narrow portions of the vessels which occur at the joints. Staining and Preserving Tube-casts.*—To stain and preserve tube-casts, A. T. Parker finds a logwood solution better than any other, made by adding five grammes of the extract of logwood, and the same quantity of alum, to 100 cem. of water. The extract and alum should be thoroughly triturated before the water is added, and the whole then left until the extract is completely taken up by the water, which requires several hours, and then filtered. The best course to pursue in staining is to shake the bottle containing the urine, then pour it into a conical flask; after several hours, when the deposit is complete, either draw or pour off the supernatant fluid, and add to the deposit about an equal quantity of the staining fluid. At the end of one or two days, the casts will be stained a beautiful reddish-purple. Casts prepared in this manner over nine months since, though left in the tube in which they were stained, are as perfect as at the time they were prepared. After staining, the casts can be mounted in balsam or dammar without undergoing any change. Method for Dry Preparations.t—Dr. G. Riehm, after stating that the method of making the dry preparations recently shown has not been published by its original inventor, describes what he terms a simple and inexpensive process for attaining the same end. After being arranged so as to show the required anatomical points, the specimen is hardened, preferably by chromic acid (Mollusca), Miiller’s fluid, picrosulphuric acid or (when the tendency to shrink- ing is not great) in aleohol. All water must then be extracted with absolute alcohol; if this is not thoroughly done, shrinkage occurs later. It is then placed in oil of lavender or oil of turpentine (the latter is, however, sensitive to traces of water), and, when quite saturated, extended with pins or otherwise on filter paper and left there for forty-eight hours. The specimen has then a brilliant white colour and maintains its colour and condition if protected from dust. The principle of the method consists in the prevention of decomposition by removal of the water and the pro- tection of every particle from the action of the aqueous vapour and oxygen of the air by an investing film of resinous matter, the result of oxidation of the turpentine or oil of lavender. The cost of preparing such an object as the frog’s intestine is about 30 pfennings (8% pence, English value), and may be reduced by distilling the oil and using it again, and by employing the old absolute alcohol for approximate dehydration of other specimens, an important recom- mendation in the case of museums and other institutions. A dealer in Halle, named Schliiter, undertakes to supply specimens of the more * Amer. Mon. Micr. Journ., iii. (1882) pp. 153-4. + Zool. Anzeig., ix. (1881) pp. 672-3. 706 SUMMARY OF CURRENT RESEARCHES RELATING TO ordinary objects, prepared in this way. By comparing this process with that described at p. 706 of vol. i. (1881) of this Journal, it be seen that Dr. Riehm’s is essentially the same as that of Prof. C. Semper. This gentleman asserts * his claim to the credit of having first made it public, and mentions three other scientific men who have published similar accounts. He disputes Dr. Riehm’s explana- tion of the action of the turpentine, stating that the prepara- tions are readily softened by water. The expense, also, in time and material is not small. Although the white colour seems to be an advantage, it may sometimes be necessary to restore as nearly as possible the colours of life, and this may be done by immersion in a mixture of glycerine and solution of sugar, and then drying; or the white objects may be painted either with honey or oil colours. Preserving Infusoria, |—E. Maupas, referring to M. Certes’ view that the exposure of the Infusoria to the action of the vapour of osmic acid should last from 10 to 30 minutes, says that this time appears to him much too long. He obtains a result much more rapid in the following way. Deposit the drop of water containing the Infusoria so that it shall spread as little as possible.on the slide, and then invert it over the neck of the bottle containing the osmic acid (1 per cent.) having an opening sufficiently large so that the drop shall not touch the sides. By this plan the Infusoria never resist more than half a minute. Mounting Mosses and Hepatice.t{— M. Delogne recommends glycerine-gelatine which is specially valuable for the study of the stipules of the Hepatice, organs which are ordinarily very difficult to see. A special advantage is that it renders a cell unnecessary. Preparing Bacteria of Tuberculosis.$—Dr. EH. Van Ermengem, referring to Ehrlich’s improvement of Koch’s method,|| describes some modifications of his own which makes it absolutely sure in its results. , Instead of making a solution of the aniline in water, which only takes up 1 part in 30, an alcoholic solution is made, 4 grammes of liquid aniline in 20 grammes of alcohol at 40°, adding an equal quan- tity of distilled water, and filtering before use. The most stable coloring agents the author finds to be sulphate of rosaniline and methyl-violei BBBBB. The preparations, after having been decolorized by dilute nitric acid, are well washed in distilled water. ' Baumgarten also recommends § the following as more simple and expeditious than any others. After having spread the tuberculous matter on the cover-glass, ii is placed in a watch-glass and covered with distilled water, to which is added some drops of a 33 per cent. * Zool. Anzeig., v. (1882) pp. 144-6. + Arch. de Zool. Expér. et Gén., ix. (1881) p. 360. See this Journal, ii, (1879) 5 SBill, y { Bull. Soc. Belg. Micr., vii. (1882) p. cl. § Ibid., vii. (1882) pp. eli—iii. || See this Journal, ante, p. 572. { Centralbl. f. d. Med. Wiss., 24th June, 1882. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 707 solution of caustic potash. Without any further preparation the bacteria may then be recognized under a power of 400-500, particu- larly if a light pressure is applied to the cover-glass so as to disengage the bacteria more completely from the detritus which surrounds them. To distinguish them more clearly from the other bacteria, the cover- glass may be dried by passing it rapidly two or three times through a flame and then staining by a concentrated aqueous solution of aniline violet or other colour. The bacteria of tuberculosis are absolutely colourless, while the other bacteria, micrococci, &c., are plainly coloured. The whole process only takes ten minutes. Preparing Diatoms.*—Dr. R. 8. Warren gives detailed directions for the preparation of diatoms, especially for separating them from sand and broken species, the directions for which hitherto published he thinks are insufficient. Coarse sand may be got rid of by repeated settlings and decantations, but it is different with the fine sand. Graduated settlings and decantations have been advised, but these are insufficient, as despite all care, more or less of light silt will float with the light forms of diatoms, and the heavy forms will fall to the bottom with the heavy sand. Whirling in an evaporating dish has been advised, but this is insufficient, and Dr. Warren has found no method better than the one he has used for several years, and which he has never seen described or hinted at except in regard to whirling.t “Tf the material contains the lighter forms only, I first use whirling force as follows:—I take an evaporating dish of a size according to the quantity of material, and fasten it on the wheel of my turntable by means of a narrow rubber band passed over it and under the wheel. The material is diffused in five or six times its bulk of water. An empty wide-mouth bottle is near the turntable, and should have the capacity of two or three times the quantity of diffused material. Shaking the material well, I fill the evaporating dish about two-thirds, and then whirl it with considerable rapidity till I think the sand has mostly settled at the bottom of the dish, for the whirling motion causes it to fall. I then pour off the un- settled portion into the empty bottle, and add more of the material to the sand and diatoms remaining in the dish, and stir with a narrow strip of glass; the whirling is repeated; and so on with all the material. When this has been done, water is added to the portion in the dish, and the process continued till no diatoms remain in the sand. To ascertain this, the dipping-tube again comesinto use. The material is treated in this way several times, till no sand can be obtained by it. If the material contains heavy diatoms like the large Pinnularie, Triceratium favus, aud heavy disk-forms, the whirl- ing process cannot well be used, for these heavy forms fall to the bottom of the dish with the sand. “ After the above process is ended, I proceed as follows, and this is, * Amer. Mon. Micr. Journ., iii. (1882) pp. 111-5. + Mr. F. Kitton subsequently (op. cit. p. 153) refers to his own papers in ‘ Science-Gossip, 1877, pp. 145 and 217, as containing all or nearly all Dr. Warren’s methods. 708 SUMMARY OF CURRENT RESEARCHES RELATING TO in most cases, the only method used after the boiling and washings. I have a slide of polished glass 34 inches by 44 inches ; a smooth block of wood 4 inches by 5 or 6 inches, and 3 inches thick; two wide- mouth bottles of 4 to 6 ounces capacity, with thin, projecting lips, one empty, the other filled with the material thinly diffused in water ; several pieces of considerable size of old worn cotton-cloth, and, for I like it best, a clean linen pocket-handkerchief, and a small table. The table I place beside my wash-bowl, which is supplied with water—not filtered in this instance—through a pipe and faucet, and on it are arranged my bottles, block, and cloths. I place the glass slide on the block, taking care that the latter is level, and, well shaking the material, pour a little of it on the slide, and then quickly pour it off, tipping the slide so that the material will flow off from a corner of it into the empty bottle. The diatoms float off into the bottle, and the sand adheres to the slide. The slide is then washed by letting water upon it from the faucet, then wiped as well as may be with one of the large pieces of cloth, and then the surface to be used is wiped with the linen handkerchief. This last wiping dries the surface thoroughly, and removes any little shreds of cotton which may have adhered to it from the cloth. Careis taken that none adhere. In this way the material is all worked over, and this treat- ment has to be repeated perhaps many times before the material is sufficiently rid of the sand. It may be that before this is accom- plished, the sand and diatoms will cling together on the slide, causing considerable loss of the latter. This is owing to little particles of matter getting into the material from the cloths, or from the air, and cannot be prevented. As soon as this clinging is detected, which is easily done by occasionally examining the slide under the Microscope, first drying it after pouring off the material, the latter should be boiled for a minute in sulphuric acid, to which is added a little chlorate of potash while boiling. Of course the diffused material is poured into a beaker, allowed to settle, and the water drained off. It is then washed and the treatment continued. When the material is at last freed of sand, it is boiled a last time in sulphuric acid, chlorate of potash being used as before. It is then thoroughly washed and properly diffused in dilute alcohol for mounting. The alcohol should be filtered as well as the water. “Tn this last process some of the diatoms will adhere to the slide, but this is of little consequence if there be plenty of material. As the cloths get pretty wet, as they will, they should be exchanged for dry ones.” Modification of Paraffin-imbedding.*—The ordinary method of imbedding delicate objects in paraffin is attended with so many objections, such as the disagreeable shrinking, britileness, and fragility which the object shows by lying long in oil of turpentine or in a warm solution of paraffin in oil of turpentine, that O. Biitschli endeavoured for some time to find a substitute for the latter. After several experiments he found chloroform to be a very excellent sub- * Biol, Centralbl., i, (1881) pp. 591-2. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 709 stitute, and has used it for some time with most satisfactory results. The following is the method employed in the preparation of very delicate objects. After having removed the water from the object in the usual manner by alcohol, it must be laid for a short time in pure chloroform, until it is completely saturated. The object is then placed in a solution of paraffin in chloroform which is so made that it is fluid at a temperature of 30-49° C., but firm at a moderate temperature. To retain it in a fluid state while the object is in it, it is sufficient to place it in lukewarm water. The author prefers a solution of paraffin in chloroform saturated at 85°C. In this the object is placed until it is thoroughly impregnated with the solution, for which 3-1 hour is sufficient. The object is now placed in a watch-glass with a little of the solution, and the chloroform is completely evaporated at a very moderate temperature (40-50° C.), which is sometimes a long process as the chloroform escapes very slowly when mixed with paraflin. Larger objects can be transferred direct from the solution into melted paraffin in the same way as in using the mixture of paraffin and oil of turpentine. For delicate objects which must be completely and uniformly saturated with paraffin, the first method is in any case more to be recommended. Complete evaporation of the chloroform is also a necessity, for the presence of even a small quantity is apt to make the paraffin very soft. To make the sections the object can either be poured with the melted paraffin upon a small piece of paraffin, or after it has been placed in a larger mass of melted paraffin, it can be poured into a paper box in the usual manner. This mode of imbedding is the most harmless and effective which the author has hitherto employed. Both object and paraffin form a thoroughly compact mass, which can be cut exceedingly uniformly, The paraffin which remains after the evaporation of the chloroform . is of a very uniform structure without any tendency to crystalliza- tion, which very much favours the making of thin sections. With careful manipulation a thorough filling of the smallest inter- stices of the object can be effected, and there need be no apprehension of shrinking or brittleness. The author (who acknowledges the assistance of Dr. F. Bloch- mann) mentions some of the cases for which they have found the pro- cess very successful, viz. Amphioxus, Cerianthus, tape-worms, ambulacra of Echini, decalcified ambulacra of Holothurians, gelatinous parts of Ctenophora, Hydroid polyps, &ce. Of large objects, such as cross- sections of Amphiowus and Cerianthus, sections can be made without difficulty of ;1, mm. in thickness. Of small objects, as the tentacles of Cerianthus, or entire Hydroid polypi, sections can be made of 545 mm. ; if Thoma’s microtome is used, indeed under some circumstances ae to =1, mm. if the knife be placed rather obliquely to the object. Perenyi’s Hardening Fluid.*—Dr. J. Perenyi describes a new hardening fluid for embryological purposes which has given surprising * Zool. Anzeig., v. (1882) pp. 459-60. 710 SUMMARY OF CURRENT RESEARCHES RELATING TO results. Its advantage consists in the fact that the ova do not become porous, and that the segmentation spheres, as well as the nuclei, remain fixed in their respective divisions. The ova may be cut like cartilage. The composition of the fluid is :— Nitric acid (10 per cent:) 3." 2 ee paris: Aleohol vi ke a Scie eee Chromic acid (0°5 percent.) .. .. 3 ,, which after a short time forms a violet fluid. In this the ova are placed for 4-5 hours, then for 24 hours in 70 per cent. alcohol, for a few days in strong alcohol, and for 4—5 days more in absolute alcohol. For staining, either (1) the fluid itself, or (2) the oil of cloves, can be coloured. The first method is more convenient because quicker, since the ova are hardened and coloured at the same time. The outer albu- minous coat should, however, be removed, so that the staining fluid may penetrate better. Some colouring agents, such as eosin, purpurin, and aniline-violet, must’ be dissolved in three parts of alcohol before they are added to the hardening fluid, whilst others, such as fuchsin and aniline-red can be dissolved direct. Very beautiful pre- parations are made by colouring the fluid with picrocarmine or borax- carmine. To get rid of the sediment produced by these agents the fluid must be filtered before the ova are laid in it. For washing, 5 per cent. alcohol is first used (5 hours), then ordinary alcohol (10 hours), and then absolute alcohol; for clearing, oil of cloves; and for mounting, Canada balsam. By the second method the ova are hardened and cut, and the sec- tion placed on the slide wetted with one or two drops of coloured oil — of cloves. In 5-10 minutes the latter is sucked away with filtering paper. The oil can be coloured with eosin dissolved in alcohol or with safranin. If entire ova or embryos are freed from their outer albuminous coat and hardened, then taken out of the alcohol, left free until the alcohol is evaporated, and then wetted with a few drops of oil of cloves or tur- pentine, very excellent and stable preparations are obtained for the study of the outer segmentation. . Satterthwaite and Hunt’s Freezing Section-cutter.*—Dr. T. E. Satterthwaite, in conjunction with Dr. J. H. Hunt, has devised a modification of the ordinary freezing microtome, shown in Fig. 134. It consists of the brass cylinder S, made of rather large size and placed in the centre of ametallic box B. The length of the cylinder, with milled head D, is about 5 inches. The diameter of the well a is 13 inch. Fitted round the cylinder is a plate glass for the knife to sweep over. * Satterthwaite, T. H., ‘A Manual of Histology.’ 478 pp. and 198 figs., 8vo, London, 1881. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. Tit The knife A A is large, measuring 13 inches in length, including handle and 12 inches in breadth. It is slightly concave on both sides, and is fitted into a brass frame c,c, 74 inches by 31 inches. Two Fie. 134. strong brass springs and two sliding clamps hold it in place. The knife and frame are modifications of Dr. Curtis’s plan. The well is so large that it will hold an ordinary kidney after hardening, or, at least, so much of it that a section may be made of the whole organ at one sweep of the knife. Each revolution of the milled head raises the preparation !, inch, and as it is divided into 30 divisions, each division represents 51,5 inch. Gis an indicator for marking the thickness of the sections, EE are tubes to fit in well, F F plugs, H H covers to the box, and . K a binding screw to attach the latter to a table. Windler’s Microtome.* — This (Fig. 135) is a modification of Rivet’s microtome, but retains little more than the principle of the original, i.e. the inclined (ec d) and horizontal (b) slides attached to the vertical plate (a), these parts being all of metal. Instead of the ordinary clamp, which is very unsuitable for delicate objects, the inclined slide on the left supports a brass slide e, the under surface of which is lined with lead. Metal cases of different sizes 1 for the object to be cut, can be placed within it, and fixed by the screws n. * Bericht wiss. Instrumente Berliner Gewerbeausstellung im Jahre 1879 (L. Loewenberg, 1880) pp. 309-12 (2 figs.). 2 SUMMARY OF CURRENT RESEARCHES RELATING TO The elevation of the slide as it is pushed forward can be read off on a scale on the vertical plate and a nonius. The knife o is attached to a slide f (Fig. 136), which has an eccentric disk g on its upper surface. By turning this disk the knife, High 35: which is fixed by the clamp-screw 7, can be brought into any desired position. There is one defect in all sliding microtomes, which consists in the tendency of the knife, when fastened only at the handle, to give Fie. 136. way at the free end of the blade on any resistance in the object. This defect is remedied by the metal bow &, the slit end of which passes through the axial screw h, while the front portion is attached to the knife by the screw p, by which means any displacement of the end of the blade is prevented. Marsh’s Section Knife.* —It is frequently suggested that the surface of the knife which has to glide along the cutting-plate of the * ‘Microscopical Section-cutting,’ 2nd edition, 1882, pp. 32-3 (2 figs.). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 7138 microtome should be ground flat. This Dr. 8. Marsh considers to be a most unsuitable arrangement, as a very little actual experience of section-cutting will speedily demonstrate. After many unsuccessful attempts to obtain a really good and Fic. 137. yeliable section-knife, he had one Fie. 139. i I | made, which has proved everything that could be desired. The knife is shown in Figs. 137 and 138, the latter being a trans- verse section of the blade. It is fur- nished with a blade 4 inches long and 2 inch broad, set in a square 3} handle of boxwood, also 4 inches in 7 length. The thickness of the blade i 1 i at the back is not quite a } inch, while both of the surfaces are ground slightly hollow. It is essentially necessary that the back and edge of the blade be strictly parallel to each other; that is to say, the edge must form a straight line, and both the edge and under side of the back must lie in the same plane, otherwise the knife, when in use, will have such a tendency to tilt over as to render its management extremely difficult. It is very easy to discover if this con- dition be fulfilled, for if, on care- i fully laying the flat of the blade upon a piece of level glass, every portion of both back and edge are found to be in close contact with it, the knife may in this respect be considered perfect. Thanhoffer’s Irrigation Knife.* — This (Fig. 139) devised by Professor L. v. Than- hoffer, and adapted either for free-hand cut- ting or with a hand microtome, consists of a blade (wedge-shaped in section) 11 cm. long and 23 cm. broad, a handle 125 cm. long and 1} cm. broad, and a tube (a b) for sup- plying water to the blade. This tube is attached to the back of the blade, and is there pierced with a row of fine holes; it also traverses the handle and terminates at its butt- end in a tap, to which an indiarubber tube may be attached. The fixed tube is supplied by the indiarubber feeding-tube with water from a vessel placed on a higher level or from a water-main. The water comes out of the small holes in drops * Arch. Mikr. Anat., xix. (1881) pp. 315-7 (1 fig.). 714 SUMMARY OF CURRENT RESEARCHES RELATING TO and flowing together covers the blade with a layer of water along its whole length, even when it.is lightly smeared with oil or has become greasy from the imbedding mass. It should, however, be kept in a horizontal position, or better somewhat inclined to ensure the water flowing over it. A vessel is placed under the hand to catch the water and also the sections which can be floated off by its aid, an important advantage of the instrument. If very large sections are required, the tube should not be directly attached to the blade, but a few millimetres above it. The section can then be floated off between the tube and the blade. Differential Staining of Nucleated Blood-corpuscles.* —It has been urged against the differential staining of histological structures, that the process may induce an alteration which may be mistaken for the normal condition. That this is, in many cases, true, is beyond question, but Dr. A. Y. Moore considers that the exceptions are far too numerous to justify it as a rule. For some years past he has used a process for the double staining of nucleated blood-corpuscles, which causes no alteration, except of course in colour, and as the structure can be seen much better in a semi-transparent than in a. more perfectly transparent body, the corpuscles thus stained offer advantages for study which are not found in those left unstained. The fluids used for this purpose are two, viz.:—A. Hosin, 5 grains; distilled water, 4 drachms; alcohol, 4 drachms. Dissolve the eosin in the water and add the alcohol. B. Methyl-anilin green, 5 grains; distilled water, 1 ounce. The blood should be spread upon the slide, by placing a drop upon one end and quickly drawing the smooth edge of another slide over it. This, if well done, will leave a single layer of corpuscles evenly spread over the central part of the slide. When the corpuscles on the slide are thoroughly dry, which will only require a few minutes, the slide should be “‘ flooded” with stain A. This should be allowed to remain on for about three minutes, at the end of which time, it may be washed by gently waving back and forth in a glass of clean water. Before it is allowed to dry, the corpuscles should be again flooded, this time with stain B. After two minutes’ exposure to this fluid, the slide should be washed, as before, and set away to dry. When dry, a drop of Canada balsam may be put upon the blood, a cover-glass applied and the whole gently warmed until the balsam spreads out properly. When hard it may be finished the same as is usual with balsam mounts. If now examined with the Microscope, the corpuscles will be found to be well stained with red, while the nuclei and “leucocytes” will - be a bluish-green. The granular appearance which is ordinarily seen in the nuclei, now shows with a vigour and sharpness which is diffi- cult of description, while the whole corpuscle is as brilliant as a newly- cut ruby. The Editors of ‘The Microscope’ (which since its commencement has contained much valuable matter), call special attention to the * «The Microscope,’ ii. (1882) pp. 73-6 (1 col. pl.). ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 715 above method, working microscopists having long sought after a double-staining process for blood-corpuscles in which Dr. Moore is the first to succeed. Flemming’s Modified Method for Staining Nuclei.*—A method was published in 1875 by G. E. Hermann,f consisting essentially in overstaining with anilin or azotized staining matters, and subsequently extracting the colour, except from the nuclei, by means of absolute alcohol. On this W. Flemming suggests some improvements. He finds the nitrogenized colouring-matters better than anilin colours for the purpose. Chromic acid is also preferable to alcohol for hardening, as it preserves the characters of the nuclei with more certainty. The preparations are fixed in chromic acid of ‘1 to :5 per cent. according to their nature. Only sections or thin, flat, and readily penetrable pieces should be used, and they must be thoroughly washed in dis- tilled water. They are then placed for 12 to 24 hours in closed vessels in about 1 ccm. of a solution of safranin (or one of the other colouring matters mentioned below) absolute alcohol being used diluted by about the same amount of distilled water.t The object is now transferred to alcohol which frees it from part of the colour by shaking for a short time, and then into absolute alcohol and moved about for half a minute or more until no more colour is given off, and the object appears transparent and of the desired tint. If the object is to be permanently mounted it is placed in oil of cloves, but only so long as will admit of the tissue becoming penetrated, as it draws out the colour, and then mounted in cold dammar solution or balsam. Out of a series of colours which were tested, mauvein and fluores- cent red, while staining the nuclei well, are yet somewhat unequal in their action in that some nuclei will retain more colour than the rest. Solid green has the property of being very readily extracted from the intermediate substance of the nucleus, leaving the fibrillar network of the latter well stained. If this is decolorized, the nucleoli long retain the colour. Fuchsin gives excellent colours but somewhat paler than safranin, magdala, dahlia, and mauvein. Bismarck brown is unsuitable for the above process with chromic acid. Safranin, magdala-red (or naphthalin-rose), and dahlia (monophenylrosanilin) are the most constant and satisfactory in their action. It must be noted, however, that practically the only application of the method is for nuclei-staining in chromic acid preparations. Where, however, it is desired to preserve and readily investigate the true natural structure in cell-nuclei and divisions of nuclei (which * Arch. f. Mikr. Anat., xix. (1881) p. 317-30. + Flemming subsequently stated (tom. cit., pp. 742-3) that the credit of priority so far as regards nuclei-staining with anilin colours, and decolorizing with alcohol, is due to Professor Bottcher, whose method is not, however, to be recommended for the same purposes as Hermann’s, as he uses Miiller’s fluid and alcohol, stains the sections with a solution of rosanilin-nitrate in dilute glycerine, and after extracting the water with alcohol, clarifies with creosote. ¢ Dahlia is best used in aqueous or acetic acid solutions. 716 SUMMARY OF CURRENT RESEARCHES RELATING TO succeeds best with chromic acid), the above process is to be preferred to all others. The only alternative method is hematoxylin, and that is much more uncertain in its action. Iodine-green for Human and Animal Tissues.*—Dr. H. Gries- bach recommends as the most useful of all anilin staining materials for this purpose, a new green material, tetramethylrosanilinmethyliodide, or “iodine green,” or “ Hofmann’s green.” The composition of the solution for staining is preferably 0°1 gr. erystallized iodine green, and 85 gr. distilled water, though it may be varied according to the tint required. The hardened tissue is placed for a few seconds in distilled water and then in the staining fluid, the action being almost momentary. After washing in distilled water it is transferred to glycerine or absolute alcohol, cleared in oil of cloves or aniseed, and mounted in Canada balsam or dammar. The objection to other anilin colours, that alcohol often draws the colour completely out in a few minutes, scarcely applies to iodine green, which is much more resistant. Its chief advantages, however, are its rapid action, which adapts it excellently for demonstrations, and the fact that it also often gives different tints of the same colour to different parts of the tissues. For instance in a section of the uterus of a deer, the epithelium is blue, the tubular glands dark green, the cylindrical ciliated cells of the single tubes show a splendid colouring of their nuclei, the longitudinal musculature is malachite green, and the connective tissue remains uncoloured. Hardened objects colour better than fresh. Connective tissues and bones are not coloured at all or only very slightly. Glandular organs, hardened in alcohol, are excellent objects. The gland-cells are dis- tinguished from the membrana propria by an intense and uniform colour. Striated muscle (in alcohol preparations) is coloured a cantharides green, the sarcolemma remaining uncoloured. Iodine green is also very useful for blood-corpuscles of vertebrates and invertebrates, for human white blood-corpuscles, and all kinds of isolated cells, spermatozoids, bacteria, &c. Also for ganglion-cells and axis-cylinder. In a section through human spinal cord in a chromic acid preparation (after a brief treatment with absolute alcohol and rinsing in distilled water) the horns of the grey substance were immediately coloured a uniform green, the substantia gelatinosa the same but brighter, the substantia alba being uncoloured. This is an additional advantage of iodine green as it is well known with what difficulty chromic acid preparations take certain colours. Professor Kollmann’s statement of his satisfactory experiences with iodine green is added. Teichmann’s Injection-mass.j—The exact proportions of the materials used by L. Teichmann for his injection-mass{ are as follows :— Red mass :—Prepared chalk 5 gr., vermilion 1 gr., linseed oil * Zool. Anzeig., v. (1882) pp. 406-10. + Abh. and SB. Naturw. Kl. Akad. Krakau, vii. (1880) pp. 108. Cf. Jahresber. Anat. u. Physiol., ix. (1881) pp. 11-12. : ~ Described generally in this Journal, ante, p. 125. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 717 °9 to 1 cub. cm., carbon disulphide +75 cub. cm. For the injection of entire subjects by the aorta Teichmann uses first of all a thinner mass consisting of chalk, 500 gr., vermilion 100 gr., linseed oil 120 cub. em., carbon disulphide 150 cub. em.; he then employs a stiffer preparation of chalk 1000 gr., vermilion 200 gr., linseed oil 200 cub. em., carbon disulphide 100 cub. cm. White masses, especially adapted for injection of lymphatics, have the following composition :—Zine white 20 gr., linseed oil 3 cub. cm., ether 2 cub. cm. By addition of colouring matters this mixture forms other combinations. The following pro- portions are in general suitable for a blue mass: Zine white 15 gr., ultramarine 1 gr., linseed oil 2 to 2} cub. em., carbon disulphide 1 cub. cm. The injection is made slowly by a syringe, the piston of which is provided with a screw-thread and is pushed gradually forwards by a twisting movement. The linseed oil is first boiled for eight to ten hours, and no lead compounds are added to it. Wywodzen’s Injecting Material.*—D. Wywodzen has, he says, obtained admirable results by using thymol. The proportions are :— thymol 5 parts, alcohol 45, glycerine 2160, and distilled water 1080. Mounting in Pure Balsam.j—Dr. 8. Marsh, although he cannot too strongly insist upon the use of benzol-balsam wherever practi- cable, yet points out that it sometimes happens in the mounting of substances of considerable thickness that, after all the benzol has evaporated, an insufficient amount of balsam is left behind to fill up the cavity between slide and cover. In such cases, therefore, it is advisable to use pure balsam, which may be done in the following manner :—The object having been previously thoroughly dehydrated by immersion in absolute alcohol, it is to be thence transferred to a little good turpentine or benzol, where it should remain until perfectly transparent. It is now to be placed in the centre of a slide which has been gently warmed, and a drop or two of fresh fluid balsam added, the greatest care being taken to prevent the formation of air- bubbles. Should such arise they must be touched with the point of a heated needle, which will cause them to burst and disappear. The chief difficulty of the process has yet to be encountered in the appli- cation of the cover, for it is during this procedure that the develop- ment of air-bubbles is most likely to take place. This annoyance may, however, be entirely avoided by taking the simple precaution of dipping the cover into turpentine before it is applied, when it will be found that “you can’t get air-bubbles even if you try.’ The author adds that it is to the courtesy of Mr. J. A. Kay, late of Chatham, that he is able to give his readers the benefit of this practical “ wrinkle.” Centering Objects on the Slide.t—Dr. Marsh considers that the appearance of a slide is vastly improved if the preparation be placed * St. Petersb. Med. Wochenschrift, No. 51. Cf. Jabresber. Virchow and Hirsch for 1880, p. 2. + ‘Microscopical Section-cutting,’ 2nd ed., 1882, p. 109. t Ibid., p. 101. Ser. 2.—Vot, II. Sigg 718 SUMMARY OF CURRENT RESEARCHES RELATING TO exacily in its centre. This may readily be done in the following manner :—Take some very finely-powdered Prussian blue and rub it up in a mortar with a little weak mucilage, so as to form a thin blue pigment. A quantity of this should be made so as always to be at hand. A slide having been cleaned, the best surface is to be selected, and on the reverse side, by means of a self-centering turntable, a small circle is to be drawn with a camel’s-hair pencil charged with the pigment. In the centre of this ring, but on the opposite side of the slide, the section is to be placed, when it, of course, will occupy a position exactly central. When the slide comes to be finished, the blue ring may easily be removed with a wet cloth. Chalk Cells.*—For dry mounting of diatoms, and objects not much exceeding 3, of an inch in thickness, Mr, F. Kitton has been using cells prepared in the following manner :—Wash some whitening in water to get rid of the coarser parts (foraminifera, sponge-spicules, é&c.), or levigated chalk as sold by druggists can be used, and make a mixture about the consistency of cream with weak gum water; three or more applications will make cells of a sufficient depth. When dry go over them two or three times with a solution of Canada balsam dis- solved in benzine. The cells should not be used until the balsam is quite hard; then place the cover (upon which the diatoms ought to be mounted) in position, and with a heated slide press it upon the cell; when properly attached the cement ring can be made in the usual manner. Line and Pattern Mounting.{—Mr. H. Sharp gives the following directions for this kind of mounting, his slides thus prepared being nee Mr, W. H. Wooster to be “ exquisite examples of manipulative skill.” “ Requisites :—(1) One or two cat’s or mouse’s whiskers fastened on match-like sticks or fine rushes, with shellac rather than gum, with about 4 inch free. I prefer to have one with the natural point, and another with the point cut back to where it is somewhat stiffer. (2) A good simple Microscope of some kind, either attached to a roomy stage-plate, with a mirror below and revolving plate above, or detached on some stand, but capable of being brought over a mounting table with mirror and rotating plate as above. My own is home- made, extremely simple, costing nothing but the trouble, and such as any one with a little ingenuity could make for himself. It consists of a piece of pine 9 inches long, 5 inches wide, and 1 inch thick, on three legs, with a hole in the centre, into which a wooden matchbox (with the bottom cut out) fits tightly, projecting a little above ; over this fits a piece of slate just tight enough to rotate easily ; beneath, a peg receives the mirror of the Microscope. This forms the detached mounting table. For the simple Microscope, I take the foot and tube pillar of the condenser, fit a piece of cane in this tube, drive a pickle- bottle cork stiffly on it, and fasten on this a horizontal wooden bar with a hole in the middle to fit on the cane, and another at each end * Amer. Mon. Micr. Journ., iii. (1882) pp. 151-2. + Journ. Mier. Soc. Victoria, i. (1882) pp. 94-6. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 719 in which to fit the lenses, which are just the 1}-inch and 43-inch objectives, which give far better definition than common pocket lenses. (8) A steady hand. (4) Patience and perseverance. Dry Mounts.—All diatoms and scales should be mounted on the cover, not the slide. Lay a clean cover on a slide and keep it in place by a drop of water between. As scales are larger than diatoms, it is well to begin with them. Put several on a slide in the ordinary way, pick out the ones wanted with a bristle under the simple Micro- scope, one at a time; keep the cover flooded with moisture from the breath, and deposit the scales picked up wherever wanted in lines or patterns. They will readily leave the bristle for the wet glass, and can be pushed about quite easily. When the moisture dries off no stain is left, and the objects will adhere with sufficient firmness to resist anything short of a sharp jar. When the line or pattern is finished, mount in a shallow cement cell. Balsam Mounts—The cover must have a film of a gelatinous nature which is insoluble in balsam and its solvents. A thin aqueous solution of isinglass carefully filtered serves well. A single drop is placed on a clean cover, and spread out as thin as possible with a clean needle. It dries almost instantly in warm weather, and in a few seconds in winter. A diatom placed on this film and gently breathed on is securely sealed, and cannot be dislodged without moisture. Care must be taken to place the diatom in position while the film is quite dry ; then breathe on it ; allow the film to dry again ; then place another diatom, and so on till the line or pattern is finished. If any of the diatoms are thick or likely to be crushed, stick three bits of cover-glass under the edge of the cover with gum, and place a dot of gum on each before placing the cover in position on the slide. This, when dry, will keep the cover in its place while introducing the balsam, before doing which allow a little benzine to run under b capillary attraction, which soon displaces the air from the diatoms. Then apply a little balsam to the edge of the cover and a bit of blotting-paper to the opposite edge. This draws away the benzine, and the balsam follows and takes its place. Another plan is to gum a piece of good cream-laid paper on the slide, centre on the turn- table, and make two cuts through the paper, removing the middle and outer portions and leaving a ring of paper to form a cell as large as the cover; then cut two small openings in opposite sides of the ring, gum the top of the cell and insert the prepared cover on the gummed surface. When dry apply benzine to one of the small ‘sluice gates,’ and then balsam as before. Put the slide in a warm place for several days, and finish off with white, black, or coloured varnish to fancy. Winter is the best time for dry mounts, as the breath dries off too soon in hot weather ; and summer is the best time for the balsam mounts, as it is difficult in the winter to keep the breath from moistening the isinglass at the wrong time. The cement cells should be quite dry and hard before mounting, or a dewiness will appear and ruin the object. Soften the cement over the lamp, press the cover down till it sticks all round, let stand a day or two, and finish off. No doubt the diatoms would be more secure if burnt 3.02 720 SUMMARY OF CURRENT RESEARCHES RELATING TO on the cover in the dry mounts, and possibly that process would be sufficient for the balsam mounts without the film of isinglass, as stated on p. 68 of Davies’ ‘ Manual of Mounting.’” Mr. Sharp has tried several kinds of mechanical finger, but declares he “can do the work quite as well and in less than half the time ” by the method described above. Mr. W. M. Bale also discusses * the subject of mounting diatoms in symmetrical groups in continuation of a previous paper } in which he described the process for valves which are very small and flat, and are to be mounted dry. Large or uneven diatoms are, however, liable to leave the slide at the least jar,and must therefore be attached with some cement; while any diatoms which are to be mounted in balsam must be fixed to the slide or cover with a cement not soluble in the turpentine contained therein. In these cases, a minute drop of clear gum may be deposited near the centre of a clean slide, and thinned with a drop or two of water, the whole being spread backwards and forwards over the slide with the blade of a knife till none appears to be left in the centre where the objects are to be placed. The diatoms are then arranged on the slide in the usual manner after breathing on, it, and when dry they will adhere to its surface, after which they may be covered in the ordinary way. With dry mounts especial care must be taken that the merest invisible film of gum remains on the slide, the appearance of the diatoms being spoiled if they are saturated with gum or any similar material. For transferring valves from one slide to another mounted bristles are best, one rather stout for large diatoms, and another not thicker than a human hair, and somewhat curved for lifting small valves and remaining particles of dust. Bristles are, however, too elastic for moving the diatoms into the exact position, for which a fine needle is almost indispensable. When the objects are to be mounted in balsam, the slide should be allowed to dry, and a small drop of carbolie acid placed on the diatoms, which are then to be examined with the Microscope, as it frequently happens that the gum, if not thin enough, seals up the minute cells in the valve, or even the whole cavity beneath it, pre- venting the entrance of the acid. In this case a drop of spirits of wine placed on the diatoms will usually find speedy entrance and dispel all bubbles, and while the diatoms are still wet with the spirit the carbolic acid may be placed upon them. Gentle warmth will then evaporate the spirit, leaving the acid, and it only remains to apply a small drop of balsam and a cover, taking care, if any of the valves are very convex, to provide rests to prevent the cover from crushing them. It is better to let the balsam fall on the diatoms than to apply the cover first, and let it run in, as it very often carries in with it particles of dust, cotton fibres, &c., which may be on the slide or the edge of the cover, and which are apt to come in contact with the diatoms and remain there. The running-in process is only necessary when the valves are not cemented to the slide, and when, * Journ. Micr. Soc, Victoria, i. (1882) pp. 97-9. + Ibid., i. (1881). ZOOLOGY AND BOTANY, MICROSCOPY, ETO. . TAL consequently, balsam let fall on them would be almost certain to disperse them. In most cases it is advantageous to- mount the diatoms on the cover, which is easily done by first fastening it to a slide with a drop of glycerine, which will not evaporate during the process of mounting, » and is easily removed afterwards. Large diatoms, such as Arachnot- discus, when mounted on the slide and examined by reflected light, are apt to show a slight haze surrounding the group, instead of the intense black ground which should be presented when all light is shut off from below the stage. This is caused by reflection from the under surface of the slide, and can be avoided by mounting on the cover and placing some dead-black material at the bottom of the cell. If Polycistina or Foraminifera are to be mounted, a thicker layer of gum should be placed on the slide than for diatoms, as these objects, from their peculiar forms, have usually a very small part of their surface in contact with the slide. The author considers “this branch of microscopic art as quite legitimate ” where selected species have to be mounted and provided scientific value is not sacrificed to mere prettiness. He also says that he has recently used the gum process with all balsam-mounted diatoms ‘even when they are not arranged symmetrically for the sake of the security it affords against the valves being displaced by slight pressure on the cover-glass, or by the slide being kept in other than a horizontal position, also for the advantage of being able to mount the valves in different positions so often necessary in order to get an exact idea of their true form. Kain’s and Sidle’s Mechanical Fingers.*—Mr. C. H. Kain de- scribes a simple mechanical finger for use with any Microscope that has the fine adjustment on the nose-piece. It is designed to obviate the inconvenience of the one described by Professor H. L. Smith,t which requires the loosening and tightening of the objective for the purpose of focussing, It consists essentially of a slotted bar (Fig. 140), which may be firmly clamped to the upper (immovable) bar of the fine adjustment by means of a milled-headed screw. Through the end of this is fastened a round rod, at such a distance from the objective that, when lowered, the end will not strike the stage. Over this rod slips a split tube, to which is soldered, at an angle, a smaller tube. Through the small tube passes a rod carrying a glass thread at its extremity. This rod is easily rotated by means of a milled head. The capillary glass thread is attached to the extremity by means of beeswax. ‘There is no revolving collar, as it is quite unnecessary, especially when the Microscope is provided with a revolving stage. By dispensing with the revolving collar and making all movements depend entirely upon the adjust- ments of the Microscope, greater stability and accuracy in working are secured, * Amer. Journ. Miecr., vi. (1881) pp. 149-51 (1 fig.). ¢ See this Journal, ii. (1879) p. 952. 122, SUMMARY OF CURRENT RESEARCHES RELATING TO The author says :— , “To use the finger, the point of the glass thread is first brought into the focus of the objective, or nearly so, by sliding the tube on the vertical rod, and pushing or pulling the rod carrying the thread until the desired position is attained. It is not difficult to do this, Fic. 140. and having once been done by hand, it does not have to be repeated, as all further movements are made by the adjustments of the Micro- scope. Supposing now the point of the glass thread to be in focus; by means of the fine adjustment throw the focus ahead of the point, then, by means of the coarse adjustment, rack down and search for the object you wish to pick up. Having found the object desired, again bring the point of the thread into focus by means of the fine adjust- ment; then rack down with the coarse adjustment and pick it up. Now rack back with the coarse adjustment, remove the slip on which the material is spread, and place your prepared slip or cover upon the stage. Again, by means of the fine adjustment, throw the focus ahead of the object, rack down with the coarse adjustment, and search for the spot where you wish to deposit the object, and having found it, again focus the object, then rack down with the coarse adjustment, and when the object touches the slide and has been placed in proper position, fix it by means of a very gentle breath. I prefer this mode of fixing instead of the arrangement of tubes proposed by Professor Smith. I coat the surface of the cover or slide upon which the diatoms are to be fixed with an exceedingly thin film of gelatine, prepared thus :—Dissolve 2 drachms of Cox’s gelatine in 10 drachms of acetic acid by the aid of a gentle heat. When the gelatine is thoroughly dissolved, add 1 drachm of alcohol and 1 oz. of distilled water; stir well until thoroughly mixed, let stand some hours, and filter through the finest filtering paper. Keepin a glass-stoppered bottle. ‘To coat ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 723 the cover or slip I dip a small needle in the solution and wipe it once flatwise across the glass. There are many little wrinkles which the worker will acquire from time to timé. One of the most important of these is the art of using the finger as a lever for moving diatoms or other objects into position when very slight movements are necessary. To do this, move the slide by hand until the point of the finger is just behind the object to be moved; then, by racking down with the coarse adjust- ment, the glass point pushes the object ahead of it. By a succession of pushes the object may be moved into any desired position. The coarse adjustment may be used in a similar manner for turning diatoms on edge or upside down, by pushing them against some fixed object and forcing the glass point under them. By using a point rather firmer than usual, the valves of a diatom may be separated. To do this I usually fasten the diatom on a slide which has been coated with gelatine, and when it is firmly fixed, the upper valve may be punched off without much difficulty. Another wrinkle, and quite a valuable one too, is what might be called a scientific use of the imagination. Many cannot work a mechanical finger well without an erecting eye-piece, on account of all movements appearing to be reversed. This difficulty will disappear if the worker will just imagine, as he holds the stage and moves it, that he is holding the finger and moving it; all motions will then appear to be perfectly natural. I might state here that a mechanical stage is not the best for this kind of work. There is a popular misconception in regard to the mechanical finger which it may not be amiss to mention. Many regard it as a kind of scientific plaything—an instrument used merely for arranging diatoms so as to form pretty slides. I have no doubt but that it will come eventually to be regarded as one of the microscopist’s most valuable accessories, and one which every worker will require. It may be used not only in handling and studying diatoms, but also other objects which are too small to be handled in the ordinary way. In studying the Infusoria, for instance, a drop of water containing them may be placed in a concave slide, then, when the water has been almost evaporated, or has been removed by means of bibulous paper, the Infusoria may be picked out with the mechanical finger and studied, or deposited on a slip for mounting. A firm thread of dark- coloured glass is best for this. In studying diatoms, a mechanical finger is almost indispensable, for it may safely be said that one is not thoroughly acquainted with a diatom until he has turned it over and viewed it in all its aspects. In mounting diatoms for study it is well to mount a number of the same kind in various positions, so as to display the various spines, undula- tions, or other peculiarities. How often it happens, too, that in a mixed gathering of diatoms—and it is not easy to obtain pure gatherings—we find a rare frustule which we should like to preserve. By means of a mechanical finger the frustule may at once be selected and mounted. When one wishes to arrange diatoms so as to form symmetrical 724 SUMMARY OF CURRENT RESEARCHES RELATING TO figures, an eye-piece micrometer will be found very useful, not only in selecting diatoms of uniform size, but also in determining their position. A circle ruled in squares and used in the same way as the eye-piece micrometer will be found still more desirable. It is a good idea to keep a number of glass points, of different degrees of fineness, ready prepared ; that is, attached to little rolls of beeswax, so that if a point is unsuited for a particular work another can be substituted in a moment.” Messrs. Sidle have also modified the mechanical finger described ante, Vol. II. (1879) p. 952, by adding a micrometer-screw with a milled-head nut for moving the point of the glass thread in and out of focus, thus avoiding unscrewing the front of the objective. The sliding rod has been retained for getting it approximately into position. By a later improvement the glass “hair” or bristle is carried on a second rod through a sleeve attached to the first or vertical one, nearly at right angles. Thus, by the rotation of the second rod, and of the entire apparatus around the axis of the Microscope, the diatom may be brought into any desired position. Venice Turpentine as a Cement.*—Professor C. B. Parker says that his attention was called to a substance known in the Pathological Laboratory, at Vienna, as Venedischer Damarlack (Venetian dammar varnish), which was exclusively used for sealing and finishing glycerine mounts. No such substance is known to the American trade, but he found after experimenting that Venice turpentine, prepared as presently to be described, if not identical, at least answers” every purpose equally as well. The following are the directions for preparing the turpentine. Dissolve true Venice turpentine in enough alcohol, so that after solution it will pass readily through a filter, and, after filtering, place in an evaporating dish, and by means of a sand bath evaporate down to about three-quarters of the quantity originally used. The best way to tell when the evaporation has gone far enough, is to drop some of the melted turpentine, after it is evaporated down to about three-quarters its original volume, into cold water, and on being taken out of the water if it is hard, and breaks with a vitreous fracture on being struck with the point of a knife, cease evaporation and allow to cool. Square covers should be used, and the cover-glass being adjusted with the usual precautions observed in glycerine mounting, the surplus glycerine, if any, should be wiped away, and the slide so placed that the edges of the cover-glass are plainly seen. A piece of wire, No. 10-12 (copper is the best, as it gives to the turpentine a greenish tinge), is bent at right angles, the short arm being just the length of the cover-glass. The wire is heated in the flame of an alcohol lamp, and plunged into the prepared turpentine, some of which adheres to it. The wire is then brought down flat upon the slide at the margin of the cover, and the turpentine will distribute itself evenly along the entire side of the cover. The same process is ~ to be carried out on each of the other three sides. Any little uneven- ness may be removed by passing the heated wire over it. * Amer, Mon. Micr. Journ., ii. (1881) pp. 229-30. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 725 The advantages claimed for this substance, over all others used for a similar purpose, are that it is secure. Such thick objects as the female organs of Vermicularis and Tricocephalus dispar in glycerine, are now as tight and firm as when first mounted in 1878. It hardens immediately. The moment the heated wire is removed, the specimen may be cleaned and handled without fear, a great advantage over such slow-drying fluids as dammar and balsam. It never runs in, as white zinc and other cements are apt to do. Metal Caps for Glycerine Mounts.* — Mr. F. Enock protects objects mounted in fluid from damage by external pressure by a small metallic ring of angular section fitting closely round the outside of the cell and at the same time slightly overlapping the cover-glass, entirely closing in the rim. He writes: —“I have had much bitter experience with preparations mounted in glycerine, which suffer injury from clumsiness in handling, more than the fault of expansion; for after a preparation has been mounted two or three years, the cement becomes very hard, and if injured by a fall, or knock against the Microscope, starts a leak. The number of preparations ruined by my customers in this and other ways, prompted me to find a remedy, or to lessen the chance of injury. I have now devised the metal caps, which so far have stood the heavy thumps of the Post-office men, and all the clumsy treat- ment which many give them. The caps are made to fit Pumphrey’s vulcanite cells, as they are the only cell to be depended upon for size and shape. I never use any other. My plan of using these caps is as follows:—After having fixed the cover properly and without leakage, I wash the preparation under the tap until all traces of glycerine are removed, then run a good thick ring of any kind of cement round the edge of the cover and cell, finally dropping on the cap, when the mount should be placed aside for a week, so that the cement or varnish may properly set. I use these caps for all deep cells, as they prevent the cover from Fic. 141. being pushed off, and am having some made half the depth of those sent, for shallow cells.” Nassau Adjustable Spiral Spring Clip.—This clip, the construction of which is sufficiently explained by Fig. 141, can be instantly adjusted by a screw move- ment to any degree of pressure required upon the cover-glass in mounting. Green Light for Microscopical Observations.—-We briefly alluded to this subject in the previous vol- ume,{ but it may be well to record somewhat more specifically that Professor T. W. Engelmann strongly recommends the use ot green light for delicate observations; it not only spares the eyes, but also gives images which are markedly sharper than al bopoan 7 —_—f}}} rTM | —— ss — esc. es 2 en, ae ne Rede Dimensions of Histological Elements Influence of the External Medium on the Saline Constituents of the “Blood : of Aquatic Animals on ee ee oe oe oe oe “se oe 4 is x Development of some Metazoa .. ss se ae Ae SEG HE 2, Png, Rg tosis of Dissimilar Organisms .. 0 se se we) on a se ws Pelagic Fauna of Fresh-water Lakes s+» ew oma ae nes Curious Secretion in Gasteropods ss s+ su en ue te ae we Olfactory Organ of Parmacella.. .. Pe Pep mag tT ne, Innervation of the Mantle of Laméllibranche 5. =, ° PORES ES oe Differentiation of Protoplasm in Sipe of Unionidz wad feet iae Ons Disdap lia se ee oc ee oe oo ee aw one ane oe Natural History of Doliolum op gine Sify ae ey Oe Development of Ganglion and Ciliated Sac in “Pyrosoma sect res bapa ees Development of Genital Products of Cheilostomatous Bryozoa de cake Vee Brain of Crustacea and Insects in e oa eats abaiees Want of Cutaneous Absorption in Aquatic Coleoptera sec be coset eet wae S Habits of Ants, Bees, and Wasps .. .. bs ee) Riees gy ee wate Larvx ond Pup2 of Diptera...) as se G00) ot get) ee, o> ey as Organs of Flight in Hemiptera... .. © Br eh eG a he PAL ne Fee Diversity of Type in Ancient Myriapods PEI ee PEON oe Observations 07 Scorpions. so '05. «06: sings 2 ae © wey ence ae ae Gomer eee Insecticolous Acari -.. eet nee) hee DOR L Be I ees Eis BSense-hairs of the Hydrachnida a ioe! Lbs Nase apt ah lee RR ag Ontogeny of Fresh-water nee ee oe oe eo oe os ee, ee ge, Aberrant Oniscoids . on es ee Lig? oo ae Blind Subterranean Orustacea tn New Zealand .. 1... aah eed! Synthetic Annelid oe ee os ee oe es ee oe ee oo a Elytra of Aphroditacean Anilids o« en se eo ‘oe oo) =—Cwe oer, Seat Phosphorescent Organs of comopies oni by tees. Sada tea eee ees Priapulus bicaudatus os ee es ee oe ve oe Eas ee. cee o> PAGE” : 749 ; 755 ( 3 ) Summary oF Current Resgarcues, &c.—continued. Anatomy of Ankylostoma duodenale.. .. Seek ny Rie - Structure of Trematodes -. win eth ad Adaptation to Environment in the Trematoda im Fel Pe Vascular Organs of Trematoda.. .. Vata Anatomy of Cestodes 3.0. ee ve ee ne See ae Studies on Cestodes Set eet eer sen etl shel Ligula and Schistocephalus Rio ae ier ae een New Floseularia.. .. We de Se sece a Gel 2 stat eae Desiccation of Rotifers Ce ke ae LBs Heteractinism in Echinodermata .. Circulatory Apparatus of Regular Echinoids . Structure and Development of Ophiuroids Formule for Comatulidz .. Holothuroidea of the Norwegian ‘North Sea Expedition. Histology of Digestive Canal of Holothuria . Studies on Celenterates ... erp Organization of Hydroid Polyps af Hydra .. 3 Vital Phenomena of Actiniz Ovaries of Actiniz .. is ae eee Skeleton of Madrepores’ .. «2 we we Studies on Gorgoniade’ =... 3. se Development of Aleyonaria:. _ Manual of the Sponges Development of Reniera filigrana New Fresh-water Sponges .. +. + Butane a PP OUPOR DT FA as ie Cosa t ee ge ale Go cehict ope Nab New: Cibate Infisorian 236 6. NS ea ae , Aetinophrys sol... BSF EGOS Pant ee _ Nuclei of Licberkuehnia eee aoe kate Bao a Parasitic Protozoa .. BE ES ene ae Intestinal Rapa of Oysters .. Botany. Structure and Movement of Protoplasm ... Protoplasm of Compound Laticiferous Tubes . Development of the Embryo-sae:. 2. +s ss Development of the Embryo in Lupinus Js Homology of the Ovule . .. See Reproductive Organs of Cycaden julva Structure and Growth of the Cell-wall Order of Appearance of the weinesis Vessels in Aerial Organs j Collenchyma.. . 5: Bhigeate in @ Fossil Plant... ie epee ries Spiral Cells in Crinum and Nepenthes Structure of Secretory Glands a eae Sphero-erystals.. Sp ahs ee ee Respiration of Detached. Shoots - Physiological Functions of the Tissues of Planis Chlorophyll and yi et ai oe Function of Chlorop. ss AP ESN 3 eat | Vitality of the Cheah gis papa RN ge eee We Cie Action of various Gases on Plants .. Soi eeeteree Power of Plants to absorb Carbonic Owide Formic Acid in Plants... .. Function of Liine-salis —... bo Sed Function of Resinous Substances = . Change of Starch into Sugar at low temperatures oa Colours of Flowers ~ .. is i Causes of the Etiolation of Plants Origin of Galls .. ee Male Fructification of Politriakiom ere Epiplasm of Ascomycctes— Glycogen of Plants Cell- and. Nuclear Division in the Formation ¢ bie the Pollen of H Hemerocallis PAGE 781 782 784 784 785 7386 786 787 787 788 789 789 791 741 792 792 793 794 794 795 795 796 797 797 798 798 799 799 800 802 803 804 804 805 805 807 808 808 809 810 812 812 813 813 814 815 815 816 817 818 818 818 819 819 819 820 821 821 822 823 823 824 ( 4) Summary or Current REseAROHES, ke.—continued. Agaricini .. PSM SRS ed tie Development of Sclerotium of Peziza Sclerotiorum .. .. - ec Development of the Sporangia of the Phycomycetes — «. «au Alternation of Generations in the eee BL Pia 2 ic ig, ih tid “ Mal Nero” of the Vine ss 2s ae oe oneal Aubernage: a Disease of the Vine... vee a ae ee : Parasites of the: Saproleqniew. 253) seen ose 8g ok have eee Diastatic Ferment of Bacteria... su ee ve ee Bacteria of Intermitient Fever <5.) 0. 0c nk be es we oe Bacterial Parasite of the Chinch Bug v4, gineceas See A ene make Etiology of Distemper.. ... per Experimental Production of the Bacteria of Distemper . Sees oy . os oe ae ae oe Germs of Malaria .. Seyi Certs: Sane Prevention of Fermentation by Vegetable 4 “Acids eal Wyk FONT ee g ok A a Oe Fermentation of Maize-starch.. .. Bar Br cy Geek aig 3 Fermentation of Nitrates .. 1. 1. ee meng aa oe gags Composition of Fucus amylaceus 6. an se ne neg Mazza, anew genus of Craplaphyoas Dra RON it eh de oe cnt aoe Resting-spores of Conferva.. «. a NSO an er Pens alana aE een ea Diatoms of the Baltic... Wels BN ina oes eae dea ekg eg, Motion of Diatoms (Figs. 147-149) .. Sorte! hae aes Cate eee Symbiosis of Animals and Alge = 4. +4 wt we se we Vanpyrella:-and its Allies. fe v6 Se ne ee a Mionoscory. > page 820 830 Petrographical, Mineralogical, or Lithological Microscopes. i Roenbags: re Fuess, Beck, Swift, &e. ee ay eo Aa rete epee eh Jumbo” Microscope (Fig. 156)... sos Osis orp “ Midget” Microscope (Fig. 156) .. Beck's Histological Dissecting. Microscope (Pigs w1 end 158) Gundlach’s Globe Lens... Designation of Hye-pieces .. PE atta dhs tS TaD Objectives of small and large Aperture - Correction-adjustment for He taeaeneoueaniieraoe: Objectives Nelson’s Adapter for Rapidly Changing Cuseines ae 159) — bi Z Gundlach’s Calotte Diaphragm (Fig. nue os Me ate Pesce Bohm’s Wool-measurer (Fig. 161) 2. 4, See Gundlach’s Subsiage Refrictor 62 ss cag ea eins ee we meee Apparent Size of Magnified Objects’... ae bene te ne Committee on Ruled Plates*. 9:20 4. ee gk ee ; Quekett Microscopical Club... se ae: eee oe - ta Hogg on the Microscope stats Wa Wis Od oe a ara ica eat Aes eee é Wright's Experimental Gee ve Methods of Microscopical Research 0) ‘Use in the Zoologizal ‘Station os f . Naples (Pig, 162) 0.0 ee as % Spat eee eap em Andres’ Methods of treating Actinic : ie ay sat ih item ohne wer’ Flemming’s further Method for Staining Huet Ae RN ys Se The Todine-green and Methyl-green’.. — ¥. Pica RR Ba Preparation of Bpiderinte <0 ons ge 5 ee koke Vash wheat ieee te wens Uninressed Mownting? iiss ae Sade, tp, aa ey ee ee és Staining with Magdala- red. ep Lae Aang bine: eater re . Preparing Fossil Le Spicules, te eae gas ane ate Preparation of Diatoms pad Wot ola la Hosted: cae Mounting Sections in Series — . , ee Eau de Javelle for removing the ‘Boft Parts of Preparations he Gum and Glycerine for Imbedding . Se Roy’s Microtome (Figs, 163 and 164) oy “oy Becker's Microtome with Automatic Kni fe-Carrier (rigs 16-17 in): cre Staining Bacillus tuberculosis . Sento ive OQUUATY PRG ote ci tag te AS ain UE Riek SODA de ace a pen gees Procrepinas or THE SOOTY © 04.006 0 a ae (5) ROYAL MIGROSCOPICAL SOCIETY. COUNCIL. ELECTED 8th FEBRUARY, 1882. PRESIDENT. Pror. P. Martin Duncan, M.B., F.RB.S. VICE-PRESIDENTS. Ropert Brarrawaitz, Esq., M.D., M.RB.C.S., F.LS. Ropert Hunson, Esq., F.RS., F.LS. Joun Ware Stepuenson, Hsq., F.R.A.S. TREASURER. Lionet §. Beatz, Esq., M.B., F.R.C.P., FBS. SECRETARIES. CHartes Stewart, Esq., M.R.C.S., F.LS. Frank Crisp, Esq., LLB, B.A. V.P. & Treas. LS. Twelve other MEMBERS of COUNCIL. Lupwia Dreyrvs, Esq. Cartes James Fox, Esq. James GuaisHEer, Esq., F.RS., F.B.AS. J. Wit1iam Groyzs, Esq. A. pe Souza Gurmaraens, Esq. Joun E, Inaren, Esq. Joun Mayatz, Esq., Jun. Apert D. Micnarn, Esq., F.L.S. JoHN Minar, Esq., L.R.O.P.Edin., F.LS. Wriu1um Tomas Surroxs, Esq. Freperick H. Warp, Esq., M.R.C.S. T. Cuarters Wuirz, Esq., M.R.C.S., F.L.S. Cae) I. Numerical Aperture Table. poe The “ APERTURE” of an optical instrument indicates its greater or less capacity for receiving rays from the object ‘and. transmitting them to the image, and the aperture of a Microscope objective is therefore determined by the ratio between its focal length and the diameter of the emergent pencil at the plane of its Prior ee nee that. as the utilized diameter of a single-lens objective or of the back lens of acompound objective, This ratio is expressed for all media and in all cases by nm sin’w, n'‘being- the refractive index of the medium and w tte semi-angle of aperture, ‘The value of n sin w for any particular case is the ‘numerical aperture” of the objective. — “Theoretical ss lenis of the iS Angle of Aperture (= 2 w). Hs ack Lenses of varicus : Dry and Immersion rites ary Dry _-Water- | Homogeneous ag etn Merestvey tos ie ue (n sin w= 4,) | Objectives. eens Immersion Power. Puleeto nt Inch. : std (m1) | jectives!| Objectives, J (@?. Doane 5269.u from 0°50 to 1752 N. A. . \(w=1°33.)) Ce 1°52,)-) . Fae ¥) 1:52 180°. 0! |2°310| 146,528» 1°50 | 161°. 23/5 2°250: 44d. 600- 1°48 1582 39/ 142,672 | 1°46 © 1472 42% * 140 ie ce ee 1-44 142°°.40’ 138,816 - 1:42 wed pa dioso abe. | <1 136,888 1:40 Pe ey Ba 134° 10’ | 1 | 184,960 1:38 SAR sae) (302s BB" ~ 138,032. 1°36 hs ee 126° 57’ } 131,104} 1:34 | IS) age ogo! bas7o6 > 129/176 |: 1°33 = 3 11809: 0"). 122° 6f | 28, 212. 1°32 — ae 165° 56’) 120° 33 | 1: Ne 127,248 “49 1°30 ise. a MOBO BBrit ly es eee ae 125,320.) -: 1°28 oe. | 148° 28’) 114° 44" : * 128 WOO aE ben 1°26 Oe ~) 142° 39"), 121959" | 1: Pig) WAN 40 See) ane 1°24 137° 36’) 109° 20" 119,536 1:22 133° 4'|. 106° 45’ 117,608. -1:20 128°. 55’) 104°: 15’ 115,680 Nels. 125° 3’) 101° 50! “418; 752 1°16 121° 26’). 99° 29° HALT Boat Ss 1°14 118° 00! 97°. 11’ = 109 896 aa 1:12 114° 44’; 94° 56’ ; 107, 968>>-) 5° 1:10 111° 86°; 92° 43’ ~ 106, 040 1-08 108° 36’ 90° 33 104: 112.5" 1-06 105° 42’ 88° 26' d 102, 184 =e 1°04 102° 53’) 86° 21’ |} 100,256. - 1:02 é air 100° 10’ 84° 18" , 98,328 ; 1°00, | 180°: 0'1.97° B1']2-829 37 96,400 | 1: : 0:98 157°. 2! | 94°56") 80° 4 , 94,472. ie 0:96 | 147°°29' | 92° 24) 78° Qur| 92,544. “ 0:94 ‘140° 6’ |. 89° 56") 76°24" | - 884) 90,616" - 3 0:92 138° 51’ |, 87° 32'|=. 74° 30% )° * 88,688. - 43 0-90 128°) 19" A BSS TOS FoR aB i he > 86, 760 | 0:88 123° 17") 82° 51’) 70° 44” {3 +! «84, 832. 0°86 118° 88’) 80° 34’) 68° 54% | = Be , 904 os 0°84 114° 347’ |) 78°20") 67°" 6» ; 80,9768 0-82 110° 10’ |} 76°. 8’) © 65°18! ~ 79,048 et 0:80 106° 16’ |. 73° 58") 63° 31’ “77,120. | 1s : 0°78 102° 31’ | 71° 49’| 619-45! | + fe 9 EOD aity zs 07°76 7 1°" 98°56") 6994251" 602. 9 OF ne “73,264 0) 1 a 0:74 95° 28’ | 67° 36’). 58° 16" % 71, 336 y : 0°72 92°): 6!) 69°32) ).9 5608327: 69,408 |} 1" 2 0870: a B82. 51 6B BN b4e BOl es, 67,480 | 1" 0°68 BaC aT GLOZ 30. DB Oe 65,552. |. 1° 0-66. | 82° 36’| 59° 30’| 51° 28! > 63,624 | 0-64 79° 35! | 57° B1’}. 49° 48’ ~ 61; 696 * 0°62 76° 38’ | 55° 34") 48° 9! 59, 768. }°1: 0-60 73° 44’ | 53° 38’) 46° 380’ OG 840 pea hie 0-58 70° 54’ | 51° 42’) 44° 51r- Pen eo OE gu 0-56 |. 68° 6’ | 49° 48’) 43° 14” 5B, 984 0:54 65° 22'| 47° 54’! 41° °37' te 52, 056 a pier 0-52 |: 62° 40’ | 46° 2'| 40° 0’ 50,128 290 0°50 60° -0' | 44° 10'| 38° 94" : 48,200 | Exampie.—The apertures of four objectives, two of which are dry, one water-immersion, Wan one ‘isms, would be compared on the angular aperture. view as follows:—106° (air), 157° sie hae ome 130° (oil).” ; Their actual apertures aré, however, as *80 +98 1°38 OF. their numerical apertures. - sh es ican ec ee II. Conversion of British and Metric Measures. ins *007892 -047262 086633 *126003 *165374 *204744 "244115 *283485 *322855 *362226 “401596 440967 "480337 -519708 "559078 “598449 ‘637819 -677189 716560 755930 2*795301 2:°834671 2°874042 2°913412 2°952782 2*992153 3 3 3 3 KNNNNNNNYNHNY HNWNHNNNNNNW *031523 070894 *110264 * 149635 3°189005 3° 228375 3*267746 3°307116 3° 346487 37385857 3°425228 3°464598 3°503968 3+543339 | iS] *582709 3° 622080 3°661450 3°700820 3.740191 3°779561 3°818932 3°858302 3°897673 , (1.) Liyean ~ Scale ene. Nicromillimetres, §c., into Inches, Fe. : relation of -|' Rie ces } B ins, mm. ins. | mm, * &e.; to Inches. | 1 000039; 1 039370; 51 US tegaremtas | 2 +000079| -2 “078741 | 52 fara 3 000118} 8 ‘118111 | 53 pee Fd 4 -000157| 4 157482) 54 ALERT 5 -000197| 5 +196852 55 VEN oats > 6 000286). 6» “236223 ah B 7 +000276) 7 975593) 57 et 1B | 8 000315 «8 314963 | 58 +s lE 9 +000354; 9 “354334 | 59 me 10 -000394 +10 (1cm.) °393704) 60 (6 cm.) re FE 11 :000433 11 -433075 | 61 ; E 12 -000472' 12 ‘472445 | 62 jalgl= 13. :000512 18 *511816| 63 Salle 14. -000551 14 *551186| 64 | = 15. -000591) 15 -590556 | 65 PAP 16 :000630 16 -629997 | 66 - lot 17 -000669 17 "669297 | 67 le 18 000709 | 18 ‘708668 | 68 | THB 19 -000748 19 “748038 | 69 A 20 000787 20 (2em.) *787409| 70 (7 em.) Ae 21 -000827| 21 ‘826779 | 71 = 5 | 22° -o00x66 22 -866150| 72 A + 23 -000906 | 23 905520 | 73 = alb | 24° -000945 | 24 “944890 | 74 AB 25 -000984 | 25 “984261 | "75 Es 26 001024 26 1°023631 | 76 a5 PN SBF +001063:| 27 1:063002 | 77 A '- 28 001102 28 1°102372| ‘78 | , 29. -001142 | 29 1°141743 | 79 | (Be | 80 -001181 | 80 Bcm.)1°181113; 80 Bem.) ate z| | 81 +001220 81 1:220483| 81 eles | 82. -001260 82 1°259854| 82 EH | 83 -001299 33 1:299924| 83 els » | 84 -001239° 24 1°338595-| 84 ee | 85 001378 35 1°377965| 85 | (ae | 86 -001417, 86 1:417336 | 86 $ [Em 87 -001457 37 1-456706 | 87 =| | 88 +001496, £8 1:496076 | 88 : “IEE | 89. -001535' 39 1535447 | 89 3 iE | 2240 “001575 | 40 (4em.)1-574817 | 90.(9 cm.) lstointal «| 41 «(001614 41 1:614188| 91 Bal: | | 42 001654 42 1°653558 | 92 =s , 48 +001693| 48 1°692929 | 98. . al: | | 44 001782) 44 1°732299 | 94 . TB 45 001772) 45 1°771669 | 95 mle: - 46 +001811 46 1°811040 | 96 f Es / 47 -001850; 47 1-850410) 97 ES » 48 -001890 48 1°889781 |} 98 : wiz | 49 001929) 49 1:929151; 99 (Ele ~| BO. +001969.| 60 (5 em.) 1:968522 | 100 (10 em.=1 decim.) 2 a ; eA Rl= a 60 002362 rs ule Hy 70. -002756 decim. ins. + 1B 80 -003150 1 3+937043 : jes 90 -003543 2 7874086 4 = 5 100 -003937 3 11°811130 les 200 -007874 4 15°748173 == .- 800 -011811 5 19°685216 [Es | 400 *015748 6 23622259 tera / 5OO +019685 ” 27 -559302 a | 600 +023622 8 31:496346 AO es Slim. | "700 | *027559 9 35°433389 ~10mm.=lem. | 800 031496 10 (1 metre) 39:370482 “10cm. =1dm. | 900 -035433 = 3-280869 ft, 10 dm. =i metre.|, 000 (=1 mm.) — fe t 1-093623 yds. Inches, §c., into Micromillimetres, taal She oi S| cole of wl sh ooles Slate oh oe Of ol le se ot tle S| ~ i) loo wlee | fora DODD et et | [-) OMDmNInor Whe lyd.= ec. 3 y 1°015991 1+269989 1°693318 2°539977 2822197 3*174972 3°628539 4°233995 5079954 6°349943 8466591 12699886 25+399772 mm, “028292 031750 036285 “042333 -050800 056444 063499 -072571 “084666 -101599 126999 -169332 -253998 “507995 1:015991 1: 269989 1-587486 1-693318 2116648 2539977 _ 8°174972 4°233295 4°762457. 5° 079954 6-349943. 7° 937429. 9°524915 cm. .111240 *269989 . ‘428737 “587486 “746234 *904983 “063732 * 222480 2°381229 2°539977 5°079954 7°619932 decim, 1°015991 1°269989 1°523986 1°777984- ~2-031982 2°285979 2°539977 2°793975 8:°047973 metres. *914392 Ser ins Bee SPRtOUh Thr ees bo are, mer toes eee ee ard ~ sgataumvsBoy1y SR ARON H LS re eae ee cag SE erences TONG a es ee LB6GES Fb Cat) PR OOO she eng tee cae, ay Pal dah, Sotel Yale g beet etm ALB oN Mates Fgh aN RS Ch cees bates Sepa: ; eM Ogg H0B-G ° CHOU De 0000T I Soko ao Rte geeks =e eevee ‘ : ‘ZO. : ‘ | atone sqy Ped te Sb re Dee ties PASI ee i meses pte “t Sisson jt ee @eD 5 aS a “| POSLEG5S -Cx80;90y T) - 000T.. ? 3 ALOR > C686LF:9 LEGS is, 100T =.) OSLeese x. Lee Dp -00L “sont 78020. pS = = ( 1) i. Le : “sq183 1600%3- = Sbo Mince) Oe RTI CNS FL a po target atk "ATOR 20. i et elas -BO98E9 T YEG Mae ate Oot 8 uid VA ars Fae COSALE. Oe ae Ec) te GPR BBPKET 3° ey one eS Beet ae one Dane 1s gare 906188-¢ ~ 6 FLIGSS*Sl 6. Ce AURAOTERT ae aes ORS a "QN9 STSSE0. = 9IGE8T +S 8 GLESEE “ZI s. POOLE Tek cr oe OB | ~- 188¢Z0-19 (OT D 0001 L6SES-F kb | -¥F9608-0T bo eae Se AS : S¥82G6- FS 006 » LEGLES + <9) | 60FBGS-6 9 PLOTES-6 A 09 | BOL0SR- BP 008 SPEGESS eng PLIQTL: Ls ge TISS61-8 Hee OG TLLLIL-@F 00L SC616S.G +t } 6E6ZL1 +9 a -. 6FORSS-9- “ OF BESSI9-9E 009 6968h6-T. g COL6Z9-F &. ~ L86S16-F 08 €69ZIS-08 00s 6169636. T Bes OLF980+S. - Or CRGE LOGS. Go pores 0% - GCTOTF-F% 00% ‘somuTpAaep ee GECEFS + L BEE ee B99869-T OL YT9LOS: ST 008 CE86LF-9 if tagline a Q6LELE-T 6 LLOGOZ- BI 003 —~ 900TS8-¢ 6: (1s109p T) 00T > O860I8-T 8 6ESZ0T-9 CIMep 1). OOT 9T6EST-¢ » 8: -I16888-T. — "06 | FOOLPI-T L COZZER.G 06 co -LZ6G8¢-F obs SSerEs- TL 08 ge BOUHTORD TE0Z88-F 08 LEGLE8-8 9: $9G080- I OL PLEISS +6 a: LLLILZ'¥ OL ~ 8F66E3-¢ ¢. 1F6S66- 09 LISS61-8 ¢ SZS199- : 09 - 86168: ¥: LLOTLL- 0g 6FORCS-9 “§ G9ZICO.E 0¢ 696876 -T an FEGLI9- Aye OF... || L86ST6-F ~g CLOLFF-3 0F 6L6S63: T yes OLGZIP: 08 ea GEGLLE +S b ZILOES+ T 08 *SOUTUNLBAZI4UO 19808: KOS B99889-T I 808066: T 0% G686LF-9 I: SZETSL- Castju00 1) OL O6LELE:T 6- FEZOI9» CTHUe T). OL 906188 +S 60. T688EL> 6 OS601S:T 8 SZE6PS- 6 S16E8T-G 80- 6SFSEL- 8 FOOLFI-T Le GOS88F- 8 LZ6SES-F L0- 920801 - L SONITT}U09 SLILGPs L LE6L88 +8 90- ¥69G60- 9 FLOIE8 6 9. ZS199E« 9 SF668S-S CO. COTLLO- ¢ IIEg61-8 ¢: LZIS0E« g SS616S-% F0- 624190 + ¥ 6FOFGS-9 F BOLFES P 696846 -T $0. L6Z9F0- $ L86S16- g 9LOE8T« ¢ GLESEG- I 30. ¢98080- G CZELLZ-S G- TSOZZI- z 686L49+ 10- BEESIO- 1s 299889: 1 I: GZ0190- I ~ ‘SOULULV IB] [TOL “sulvid ‘SUTRAS *SOMLMBISITOL |, *BOAPITLL] LOL “sur *qno “soy “qno *BOIZ CT] [L UL "OR SsomnumslunaT opua “of ‘surptgpy 8) “suas ojur Sop laele ‘of ‘sougnunpy ogus “op ‘sayouy o19nD ‘of ‘soyou orgng opr “oh Ssaugypepr “LHDITM ("¢) *RLIOVAV) (*Z) ‘ponnquoo—SOANSBOT IIS PUB YSIIIAg JO MOISI9ATIOD (237) rir. Corresponding Degrees in the || IV. Refractive Indices, Dispersive Bee Fahrenheit and Centigrade Powers, and Polarizing Scales. ¢ Angles. - Fabr. Cent. |. ~ Cent Fab. |) C1.) Rernaorrve Ixpicxs. 500 260-0 | 160 212-0 |) east; “<4. 232°22 98 -- 208-4 || Diamond ‘ 204-44 96 204°8 350 176-67 | 94 201°2 ee ~-300 148°89 92 197-6 | Bisulphide of carbon 250 121-11 90 194°0 |} Flint glass 212 100-0 88 190°4 |} C las 210 98-89 86 186-8 || Crown glass Se 96°11 84 183:2 || Rock salt = 93°33 82 179°6_ |! 195 90-56 80 176-0 | Comat Dela ee 87°78 78 172:4 |} Linseed oil (sp. gr. *932) 89 °0 76 168°8 |) Oil of t ti . gr. “885 180 g2-92 | 74 Tits te | Catreraaaca CR 383 79°44 | °-7Q 161°6 | = 185 57°22 56 132°8 ; 2 130 54-44 54. j29-2 || Diamond 2 er ae 52 125-6 || Phosphorus a 48° 50 122-0 : = 40 of carl 2 115 46°11 48 Tiga dt ee 3 110 43°33 46 114°8 | Flint glass © 105 40°56 44 111-2 | Crown glass é 100 37°78 42 107°6 || 95 35-0 40 10¢ 0 || Rock salt 3. ae ae 388 100-4 Canada balsam 3 : 36 96-8 , : ; 3 80 - 96-67 34 ~ 93°29 ie oil Gp. gr. *932) ~ 75 23-89 32 9-6 || Oil of turpentine (sp. gr. 885) @ 70 21-11 80 86:0 Alcohol - ro) 65 18°33 28 82-4 ||. 3 en 3 60 1556 26 S78 - Bei, Ok ee gf —«B5 12°78 24 75°2 || Pure water 2 50 10-0 22 71:6 i} Age 45 7-22 20 68-0 | 2s ~ ~40 4-44 18 64°4 (3:) PoLarizing ANGLES S : va og 16 60°8 |} uy : . 4 57°2 s » ; | Diamond ° _ 80 — lll 12 53-6 a. : = — 3°89 10 50°0- | Phosphorus ‘aI 3 —- 6°67 8 46°4 ee . cu emer or 6 acite | sa of carbon 10° — 12°22 4 39°2 | Flint glass s 5 — 15°0 2 35°6 || Crown glass io ees = 17-78 0 BE dg oe Cae: — 20:56 | — 2 98'4 || ° — = — 93°338-*|.— 4 294-8 || Canada balsam 15: — 96:11 }-— 6 21-2 | 7; : ; ee iors 99-89) = oR 15 Binsest oil (sp .gr. °932) ; pee 25 31-67 |= 10 14:0 | Oil of turpentine (sp. gr. *886) oe — 34-44] — 19 10*4 || Alcohol age Satin & Get + 6-8 || Sea water = 40 — 40-0 | =~ 16 $9 Ihe = 45 — 42-78-) = 48 0-4 || Pure water == 60 — 45°56 | — 20 —4:0 | Air V. Table of Magnifying Powers. ES ap EYE-PIECES. Beck's 2, j % : Beck’s 1, | Powell’s 2, Beck’s 4, Beck’: 5 : Powell’s:1, and Powell’s 3.| Ross's C,. |: Beck’s 3, Powell's 4, Boss’ eB | Powell'ss, | Ross’s B Ross’s A, | Ross’s B, wages 3D. nearly.* ; ‘ a ete s .e = Foca Leneru. ~ fe . (2) : = 2 m 2 a ey s 4s as Wes ie a z g 2 in, il. in. | Lin. in. 3 An. sin. | yo in 3 in, gq in. 4 zi Macniryvine PowEr, putea i) | (pe 10: 12k | na af 1 25° | L: Gane | 40° AMPLIFICATION OF OBJECTIVES AND EYE-PIECES | COMBINED. ~ 5 2 10 15 20 ras es 40 BO.) 360-4, 80 4 22] 128 182 25 314 374 SOE GOR ce Ke LOO 8 Sy} «162 25 . B82 412 50s 662) 832 |. 100, Fe, 1382 2 5 25 4 .- 37k 50 6251 7b AOD Beeb eh AOE 3 -200'5 1k | G62 332 50 | 662 83: } 100 | 133: ) 1662 | 200 | 2662 . 1 10 50 75 100 125. |. 150 200 | 250 300 400 8,| 123) 623 932 f° 125 156 | 1873] 250 | 3122} 375 | 500° = 132] 662 | 100 1331 |> 1662 | 200 | 2662] 3332] 400 | 5331 215 e978 1124] 150 187% | 225° | 300 | 375 | 450 |. 600 > 3 20 |. 100 150 200 250 | - 300 400 500 | 600 |. 800 41 25 125 1873 | 250 3123 | 375 | 500 | 625 | 750 | 1000 1 | 80 4 150 225 300 375 450 600 | 750 |.-900 | 1200 © 8 | 882] 16624 250 8331 | 4162 | 500 | 6662] 833; | 1000 | 1383, 3 40 200°} 300 400 500 600 g00 | 1000 | 1200, 1600 ~ 2 | 50 |} | 250 375 500 | 625 750 | 1000 | 1250 ~ 1500 2000 Pa - 60 |t -300 450 600 750 900 | 1200 |) 1500.) 1800 } 2400 ~ 1} 70 |. 350 525 | 700 875. |. 1050 |. 1400 | 1750 | 2100 | 2800 2 | 80] 400 600 800 | 1000. | 1200 | 1600 } 2000 | 2400 | 3200 1 | 90} 450 675 900 | 1125 | 1850 | 1800 | 2250 | 2700 | 3600 100 500 750 } 1u00 | 1250 | 1500 | 2000 | 2500 | 3000 | 4000 — 1 a 110 | 550 825 1100 1375 1650 22.00, 2750 (|. 3300 4 4400 eas 120 600 900 1200 1500 1800 2400- 3000 | 3600-4. ‘A800 3;| 180 650 975 | 1300 1625 1950 | 2600 | 3250 | 3900 | 5200 — = 140 | 700 1050 1400 *}: 1750 2100 | 2800 | 3500' | 4200 | 5600. - 2-1 150 750 1125 4} 1500 1875 2250. 3000 | 8750 | 4500 | 6000 :° ae 160 300 1200 } 1600 | 2000 2400. | 3200 | 4000 | 4800 | 6400 3;| 170 || 850 | 1275 | 1700 | 2125 | 2550 | 3400} 4250 | 5100 } 6800 ._ Jy 180 900 1350 1800 2250° | 2700 3600 |} 4500 | 5400 | 7200. ~ zs| 190 |} 950. } 1425 1900 | 2375 2850 | 3800 | 4750 | 5700 | 7600. mS 200 | 1000 1500 2000 2500 3000 | 4000 5000. | 6000 | 8000 3-| 250 | 1250-] 1875 2500 | 3125 3750 | 5000 | 6250 | 7500 | 10000. zo | 800} 1500 | 2250 | 3000 | 3750 | 4500 | 6000 | 7500 | 9000 | 12000 . z5|400 | 2000 3000 | 4000 || 5000 6000 8000 | 10000 | 12000 | 16000 - 2; 500 | 2500 3750. } 5000 | «6250 7500 | 10000 | 12500 | 15000 | 20000 2,| 600 }}' 3000 } 4500 6000 | 7500 9000 | 12000 | 15000° | 18000. } 24000 ~~ a 800 | 4000 | 6000 | 8000 | 10000 | 12000 | 16000} 20000 | 24000 | 32000 — i ee 3 BOM ee Boyal Mlievoscopial Society. MBEEHTINGS FOR 1882, Ar 8 Pm. 1882, Wednesday, January... -. ee ee ee ey UI ¥ FrepRuary .. iestnaed (Annual Meeting ‘fer Election af Officers. and Council.) ‘i Maude 33 ion asd Pies seat ae a) RAEN 3 BEDI Cy Coit hak oi OS, OSE RRR Mae in BAS ae Oe eee ah gy age kN oe ey $s isp. (Mager eats SPEIRS Damn ae Nanas trees | 3... OctosER Uptiiigh RO) wig ine ao ten Mee x NOVEMBER 5 $5 8 Ne oe ak Nee CO 35 PRON MEE ho ee Se ee cee Just Published, price 1s. 14d. post-free, Part 3. i THE JOURNAL OF THE POSTAL MIGROSCOPIGAL SOCIETY. CONTENTS. On the Rmbeyology of the Podophthalmata, or Stalk-eyed Crustacea — The Adul- teration of Coffee'and the Microscope (Plate) —A New Growing-Slide (Illus.)—Spiders; their Structure and Habits. Part 2 (Plate) — Unpressed Mounting for the Microscope — Aquaria for Microscopic Life — How to. Prepare Foraminifera (Illws.) — An Hour at the Microscope with Mr. Tuffen West (2 Plates) — Selections from the Society’s Note- Books (Plate) — Reviews —Correspondence (Ilus.)— Notices to Correspondents, &c., &o. W. P. COLLINS, 158, Great Portland Street, London, W. THE ‘ SOCIETY”? STANDARD SCREW. The Comicit tase made arrangements for a further supply of Gauges and Screw-tools for the “Sooty” Sranparp Screw for OpsEorrvEs. The price of the set (consisting of Gauge and pair of Screw-tools) is ~ 128. 6d. (post free 12s. 10d.). Ape lentions for sets should be made to the Assistant-Secretary. For an explanation of the intended use of the gauge, see Journal of the Society, I. (1881) pp. 548-9. . i 5 ; i ADVERTISEMEN TS FOR THE JOURNAL. Mr, Cuarzes Brenoows, of 75, Chancery Lane, W.C., is the authorized aia Agent and Collector for Advertising Accounts on behalf of the Society. Aan) eae , ‘ : 1 Fj b ( 2) HENRY CROUCH'S | First-Class Microscopes, : oe Student's Microscope. New Family and School : Microscope, — 2 ‘New Series of Objectives, New Accessories, UY. NEW ILLUSTRATED CATALOGUE, ON RECEIPT OF STAMP. uieG ABROAD ae HENRY CROUCH, 66, Barbee London, E, a. AGENTS IN AMERICA, — JAMES W. QUEEN & CO., 924, Chestnut Street, Plas 5 Be <7 wae a py tH SS aH i = zs fe) be > 38 a q Ey a oe g Q a e O re) Grea 5 2) iS) CD 0: : oO = ray 0) ja () (a) ey (e) O L ) eS : @ q ) o | re) et (o} S| a Dre S Q er) & os O JOURNAL OF THE ROYAL MICROSCOPICAL SOCIETY. DECEMBER 1882. TRANSACTIONS OF THE SOCIETY. XV.—On some Organisms found in the Excrement of the Domestic Goat and the Goose. By R. L. Manpox, M.D., Hon. F.R.MS. (Read 8th November, 1882.) Puate VII. Wuen studying lately the appearances of the hay-bacillus, both in the fresh and putrid infusion of hay, it occurred to me that it would be worth while to examine the excrement of a herbivorous animal, and a grass-feeding bird. Accordingly, I procured the fresh excreta of the goat, and of the goose, taking from the latter only the part but little, if at all, contaminated with urates. The examinations were begun in the month of August last, and as they proved rather interesting, and may open up a study that may furnish results for experiment, I venture briefly to offer a few remarks upon the organisms found. Photomicrographs were made of some of these, by a Seibert’s ,4, water-immersion objective, without collar adjustment, kindly lent to me by Mr. Curties for this purpose. I may remark that the objective answered well with the EXPLANATION OF PLATE VII. (Lithographed from some of the Photomicrographs exhibited.) Fic. 1.—A few of the free and growing spores found in the mixture of the goose excrement. 5 2.—Part of the layer immediately beneath the upper layer, containing micrococci, in the mixture of the goose excrement. » 3.—Part of the felted mass of short rods, and part of some long free filamentary chains. These appeared later in the same mixture. » 4.—The earliest notice of Spirillum in the goat excrement. » 0.—Shows the marked increase in the number of Spirilla, and the diminution in the number of the rods. »; 6—Spirillum from goat excrement. [The original photomicrograph was taken with the addition of a Zeiss amplifier, and magnified to 651 diameters ; the others, each, to 365 diameters. ] Ser. 2.—Vot. II. 3 E 750 Transactions of the Society. camera extended to a certain length, and also when used with a Zeiss amplifier at the same extension; but at distances much beyond, the want of the collar adjustment became rather apparent ; hence the enlargement of the objects was chiefly kept within very moderate dimensions, yet sufficient for illustration. I may add, that I believe they are within easy reach of the engraver’s power, which apparently was not the case with the photographs of the minute organisms found in rainwater-ice and hail, described in a previous paper.* The examination was proceeded with in the following manner: a portion of fresh excrement of the goat was broken up with a clean ‘glass rod in some freshly distilled water, and immediately covered with a glass plate. Examined by the Microscope at the time, numerous bacteria of various sizes, and a very few rods of, apparently, hay-bacillus were present, besides large quantities of partially digested vegetable matter suspended in a somewhat glutinous material, most likely mucus from the intestinal canal. The mixture was set aside in the room without artificial heat, the ordinary temperature ranging between 60° and 70° F., and fully exposed to daylight. On the third day when examined there was a thin scum extending over a large part of the surface. This scum contained numerous bacteria, some small rods, and here and there in the thinner parts of the pellicle some bright oval bodies with sharp outlines. whilst free from the scum were many larger and longer rods, both straight, and with a well-marked wide curvature, not angular; these rods were in active movement; there were also a few spores with outgrowths, these had the spore ends nearly globular, and the outgrowth or extension very pale and slightly granular, with a gentle curve. These spores had a slight forward and backward movement, also a peculiar swaymg motion from side to side, the spore end forming the fulcrum. I believe these must be regarded as the spores of the Spzrillum, which appeared later. A portion of the upper part of the fluid was removed, and freshly distilled and reboiled water added both to it, and to replace the quantity removed from the original portion. Both vessels, being covered, were placed in a dark box, and kept at a pretty constant temperature of 90° F. for twelve hours, when a fresh examination was made. Both vessels now teemed with infusoria and bacteria, the fluids had become more or less ropy, especially the original one. The organisms in the diluted portion consisted chiefly of active rods of very variable lengths, many having the wide curvature. No spores were visible. ‘The original portion which had been diluted was divided into three layers, the surface one being of a dark greenish-brown colour, the second very much paler, whilst the lowest consisted of the debris of the food. * Ante, p. 449. Organisms in Exerement of the Goat, dc. By Dr. Maddow. 751 The rod organisms in the upper layer resembled those in the diluted portion, but were far more numerous, and in very active movement, the bend in the curved ones being used apparently as an axis for locomotion. The bacteria had very little motion, the fluid being most likely too slimy; no spores were visible at this stage. » “Hay was steeped for twelve hours in cold water and the liquid sterilized by boiling ; when cold, a portion was added to the original but diluted mixture and gently stirred, whilst another portion of the hay infusion was infected from the former. All three vessels were now left exposed to daylight and the ordinary temperature of the room for a couple of days. Re-examined, the long rods had almost disappeared in the hay infusion that had been infected, and chiefly very short rods could be found; bacteria and infusoria were also present. In the mixture simply diluted with distilled water, the rods were now fewer and less active; a pellicle on the surface was crowded with motionless bacteria; the infusoria still abounded ; there was no offensive smell. The original fluid, or mixture, now diluted with the hay infusion, was examined. It was densely crowded with straight and curved rods of very variable lengths, and a few spirilla were visible, some having only one-and-a-half turns, others two to six; these were in active movement. In Fig. 4 (Pl. VII.) is represented the first notice of Spirillum in the mixture. In different parts of the slide some single large micro- cocci and also smaller double ones were noticed. The infusoria still abounded, and the mixture had now a faint sickly odour. Attention was confined to this mixture. After another twenty-four hours the rods and spirilla appeared nearly equally abundant, some of the latter having as many as thirty-three angular turns. The curvatures, both in width and depth, differed considerably. These organisms continued about matched for four days, when the Spirillum got the upper hand, the number of rods lessening ; this is fairly well shown in Fig. 5. The survival of the fittest was evidently taking place, but at the same time also appeared another organism contending for the mastery, viz. a very delicate mycelium spreading in every direction through the fluid, which quickly rendered all further observation useless. The fluid was, however, kept for five weeks, and at the end of that period the rods and spirilla had well nigh disappeared, and nothing could be found by which to determine to what object the mycelium belonged. The mycelium was in very long twisted threads not larger than the rods, and at first I fancied they might be the rods in their filament stage, but close examination soon showed this not to be the case, as the threads had short outgrowths at very variable distances. In the excellent contribution upon the life-history of Spirillwm 3 E 2 752 Transactions of the Socvety. given by P. Geddes and J. Cossar Ewart, M.D., in the Proceedings of the Royal Society, No. 188, 1878, it is shown that at one term of existence, the screw-shaped rods become less twisted, and finally straight, passing into the ordinary rod form as in Fig. 7, given by them. They also suggest that the term Vibrio should not be considered as generic. When examining the above-named fluids I have repeatedly found many of the long spirilla motionless, with one half having lost all twist except a large gentle curve, but that end presented a very delicate pale, very finely granular condition, differing entirely from the other part, the end being scarcely visible even when stained, and I have regarded this as a progressive dissolution of the organism. In the case I have men- tioned we might have expected the spirilla to have reverted to rods, which was not the case, so far as [ could determine, and from the Spirillum found in the goat excrement, appearing after and so largely replacing the rods, I think it offers a fair plea that Baczllus and Spirillum are to be considered distinct, though the latter, when broken up, may greatly resemble bacillus rods. The straight rods I should regard as Bacillus subtilis, and the curved ones as merely an accidental variation in their form, though many with a single curvature had very much the appearance of Vabrio rugula. In the same paper it is stated ile parent or spore-bearing lyphee are locomotive, “and the spores quiescent.” The authors say, ‘‘ The life-history of Spirdllwm, so far as we at present know, may be thus summarized. The well-known motile corkscrew may alternate between the active and resting states, and ultimately lengthen out into a small filament, which loses its definite twist, and may freely bend or straighten. This thread grows into a much larger and longer motionless filament in which spores appear. These rapidly divide and acquire a bright brown colour, the filament re-assuming the motile condition, and sooner or later breaking up.” The spiral organisms were rigid, with a spiral movement. In size they appear rather smaller than the figures given of Spirillum volutans, and larger than Spirillum tenue, approaching nearer to the Vibrio serpens of Cohn. If the term vibrio were put aside, would it not be as well to substitute for the curved forms of Bacillus, Bacillus curvatus, or Bacillus subtilis var. curvatus, and thus help to get rid of the objectionable term? Having some doubt as to the exact species of Spaillum, I have not given more than the generic name. I found the organisms varied so considerably according as they were left dry upon the cover-glass after or before staiming, or mounted in distilled water, or in a semi-saturated solution of acetate of potash, or in dammar medium, that I have not given the measure- ment. The one method of mounting would not agree with the Organisms in Excrement of the Goat, &e. By Dr. Maddox. 753 others, as shown in some other photomicrographs, taken with the same objective, at the same distance from object to screen; but I have given the measurement of the ;)55 of an inch at the same distance. The examination of the goose excrement, the part not covered with urates, was made by breaking up a portion in freshly distilled water with a clean glass rod, then covering it with a plate of glass, and setting it in the daylight at the ordinary temperature of the room, at the same time as the former experiment. Examined on the slide, chiefly vegetable debris of grass, coarse and fine granular organic and mineral matters, with here and there a bright point, like an ordinary bacillus spore, amongst various bacteria, and a very few short rods were noticed. After twenty-four hours, a thin scum appeared in several places on the surface of the fluid, which had now settled into three layers, the heavy solid constituents having sunk to the bottom. The top one was of a dense brown colour, the middle much clearer and less coloured. After another twenty-four hours the top liquid was examined ; being diluted with a droplet of water on the slide, it was seen to contain numerous very bright oval forms, many with outgrowths of varying lengths, evidently germinating spores, ap- parently of the hay-bacillus. ‘These had motion forwards or back- wards; but not the singular swaying movement from side to side from a fixed point. ‘There were also a few short rods, micrococci, and bacteria present. These were photographed, Fig. 1. On the following day the short rods had notably increased in number, but they did not appear to grow in length; fewer spores in growth were visible. ‘Ihe pellicle on the surface had increased, the part exposed to the air consisting, so far as I could make out, of bacteria mingled with micrococci, whilst immediately beneath, the micrococei formed a layer in a delicate transparent medium. This layer is seen pretty distinctly in Fig. 2. In various parts of the pellicle on the slide, small masses of minute bodies, highly refrac-. tive and set in a gleea, larger than the spores of the hay-bacillus, were seen. I believe they belong to a Bacillus of larger dimensions, as I have many times noticed similar bodies in connection with a short chain of stout short rods, in other preparations. Continued examinations for many days revealed nothing further ; the rods had not grown, and the entire fluid was becoming of a greenish colour throughout, but at last upon several slides the bacilli were seen in chains of some length and in nearly all attached to a felted mass of small rods, and rods lying free, but close to the mass, as depicted in Fig. 3. In the filamentary chain, the joints appeared to be passing into the spore condition ina few. The little mass of free rods were motionless and of rather paler appearance than the ordinary rods of hay-bacillus; the fluid was crowded with infusoria, 754 Transactions of the Society. there were numerous bacteria, but not active to any extent. The fluid had become ropy, the dark colour had lessened, the odour had become disagreeable. An attempt was made to cultivate the organisms in fresh sterilized hay infusion, but it was unsuccessful. The original fluid was now stirred up, and allowed to re-settle, still it yielded nothing of change that 1 could discover upon the examination of many slides. It was kept for more than a month when the fluid had a sour smell and acid reaction. ‘To the latter I think we may attribute the want of growth of the rods generally ; evidently the pabulum was not favourable; at this stage a few octahedra of oxalate of lime were seen. ‘The results offered a great contrast to those of the excreta of the goat. Possibly, by fractional cultivations in proper media, we might be able to arrive at a more perfect study of the different organisms, and test their physiological peculiarities or their pathological reactions, if any. We may, I think, however take for granted that the spores haye resisted the entire digestive process in both cases, but whether they, or the spirilla, would prove detrimental to guinea pigs or mice, I must leave to the care of those armed with the necessary powers, in this country, for such studies. ( 755 ) XVI.—A Further Improvement in the Groves-Walliams Ether Freezing Microtome. By J. W. Groves, F.R.M.S. (Read 8th November, 1882.) In the present volume of the Society’s Journal, page 430, Fig. 83, is described and figured the method by which, at my suggestion, ether was adopted as the freezing agent to a Williams microtome,* the chief merit being that the used ether is capable of being con- veyed away into the external air without the operator being exposed Fic. 146. to its fumes, as is the case in most ether freezing microtomes, while at the same time the advantages of the Williams instrument are retained. * Cf. this Journal, i. (1881) pp. 697-9 (1 fig.). 756 Transactions of the Society. On page 482, Fig. 84, is shown a so-called improvement, though one which is useless, inasmuch as the razor is incapable of being levelled, and therefore cannot be kept parallel with the slides on which it works, the result being that no sections with parallel surfaces, and therefore no ¢hzn sections, can be cut. The present further modification, Fig. 146, has consequently been made by Mr. Swift, of Tottenham Court Road, at my request. The machine now resembles that last mentioned in haying an iron bracket with spring tube to receive either of the four holders for material, Figs. 84-7, and a clamp below by which it may be fixed to a table ; but differs from it in that it has the glass top and razor- frame of the original Williams microtome. The new Microtome, therefore, consists of an iron bracket to the top of which is fixed a glass plate with central aperture. Through this passes the upper end of the apparatus for holding the material to be cut, either for freezing by ether as in Figs. 146 and 84, or by ice and salt, as in that known as Pritchard’s, Fig. 85, or for material imbedded, Fig. 86, or for clamping a tree stem or other structure not requiring to be frozen or imbedded. Lach of these is held below the top in a spring tube capable of being tightened by a screw, and the whole instrument can be fixed to a table by a clamp which forms the bottom of the bracket. ‘The sections are cut by a razor held in a Williams triangular frame, which is levelled by means of two base screws, and lowered for each section by means of the apex screw. When using the ether freezing apparatus with this microtome, material to the thickness of ,2, inch can be frozen in 1% minutes, and good successive sections cut as thin as can be obtained by any microtome. When the material is once frozen scarcely any ether is required to keep up the action, so that the cost of the ether is rather less than that of ice, methylated ether sp. gr. -720 at 1s. 6d. a lb. being used. ( 757) SUMMARY OF CURRENT RESEARCHES RELATING TO 40 0:0 6Y AND “POT ANY (principally Invertebrata and Cryptogamia), MICROSCOPY, &c., INCLUDING ORIGINAL COMMUNICATIONS FROM FELLOWS AND OTHERS.* ZOOLOGY. A. GENERAL, including Embryology and Histology of the Vertebrata. Spermatogenesis in Mammalia.j—G. Renson finds that, when the testicular canaliculi of the rat are treated with osmic acid, the following sets of cells may be made out: (1) Large, rounded cells with large nuclei, the protoplasm containing a number of granulations —these are the seminiferous cells of Sertoli. (2) Multinuclear cysts provided with a variable (4-20) number of nuclei, and varying in form according to their stage of development. Frequently the nuclei are slightly elliptical, an appearance which appears to be the forerunner of their conversion into the heads of the spermatozoa; in such cysts there isa distinct differentiation of the protoplasm, which has become condensed and limited around each nucleus; so that, when completely developed, we have rather to do with aggregations of cells than with multinuclear protoplasmic masses. (3) There are also small rounded cells, the nucleus of which presents every stage in the development of the head of the spermatozoa; these, which, with Sertoli, the author calls nematoblasts, have, like their predecessors, a refractive corpuscie placed near the nucleus. The whole series of changes may be thus expressed: a genera- tion of spermatozoa is developed, and expelled into the lumen of the canaliculus ; the seminiferous cells multiply to form a new genera- tion of nematoblasts; germ-cells are developed from a peripheral protoplasmic plexus which takes on the characters and situation of the seminiferous cells ; a new generation of germ-cells is developed in the outer portion of the canaliculus, The author has not been able to determine the origin of these germ-cells. The result of following * The Society are not to be considered responsible for the views of the authors of the papers referred to, nor for the manner in which those views may be expressed, the main object of this part of the Journal being to present a summary of the papers as actually published, so as to provide the Fellows with a guide to the additions made from time to time to the Library. Objections and corrections should therefore, for the most part, be addressed to the authors. (The Society are not intended to be denoted by the editorial ‘‘ we.” t Arch, de Biol., iii. (1882) pp. 291-334 (2 pls.). 758 SUMMARY OF CURRENT RESEARCHES RELATING TO out the history of these bodies is to show that there is a regular replace- ment of one generation of cells by another, and, owing to this, a second may take the place of the one expelled. Early Changes of the Chick.*—It is certainly to be desired, in the nterests of embryological students, that the principal facts and inferences relating to the chick’s development could at length be established beyond the reach of controversy. For, alike on historical, practical, and scientific grounds, this accessible type seems likely to maintain its place as the standard of comparison for the embryogeny of the higher vertebrates, and especially for the study of their initial phases. The rapidity, however, with which these phases succeed one another, and the diverse changes which, within very short periods, occur in different parts of the same organism, present difficulties of observation so great that our most skilled experts have not yet been able wholly to overcome them. Hence our best works, those of Kolliker and Balfour, cannot be regarded as in all respects satisfactory. Hoping to dispel some remaining doubts Dr. W. Wolff returns to this familiar subject ; his observations suggest a discussion and review of certain opinions of his predecessors. As regards cleavage there is not much to be said. Why, he asks, should writers assert that it occurs more rapidly near the centre and surface than in the deeper and outer parts of the germ? Noone has proved this. A uniform rate for the change in question being assumed, it must be over sooner in the region where it began. The formation of the subgerminal cavity is best explained if we compare it to the cleavage-cavity of mammals. Since the yolk retracts before it divides, secreting at the same time a fluid mass, so, with the approximation of the cleavage-spheres, becoming successively smaller firmer and more numerous, their intercellular fluid likewise accumu- lates and in the chick is lodged within the cavity formed by.the with- drawal of the entire germ from the food-yolk below. No membrane separates the nutrient yolk from the germ. The false appearance of a membrane on the floor of the germinal cavity is produced artificially by coagulation of a film of the fluid white yolk. The margin of the hitherto lenticular germ becomes, in the lower portion of the oviduct, thicker than its centre, the central cells probably spreading themselves as the primitive outer lamina is developed. This “ectoblastoderma” is polyderic. Its cells are more easily stained than those of the rest of the germ. The under surface of the outer layer, in contact with this residuum, is uneven; but whether, once formed, it receives cells therefrom or has henceforth an altogether independent increase is not certain. There are now, in the still unincubated germ, two kinds of cells and two only, (a) those of the ectoderm, distinguished by their position, form, and chemical characters, and (b) the cells beneath them, which do not constitute a lamina and are best termed collectively the “remnant of the cleavage- elements.” These residual cells, compacted peripherally, are but loosely grouped about the middle of the germ, which, partly on this * Arch. f. Mikr. Anat., xxi. (1882) pp. 45-64 (1 pl.). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 759 account, partly in consequence of the development of the ectoderm, appears thinner than it really is. Some of them lie scattered in the germinal cavity ; others rest on its floor. The first consequence of incubation, apart from the increase of all the cells of the germ, is the transformation and union of its deepest residual cells to constitute the monoderic inner lamina or “ endo- blastoderma,” This layer consists of cells no longer rounded but like those of an epithelium and flattened, save where they are rendered thick by their large nucleus, so that in sections they seem fusiform. The under surface of the whole germ is protected by the inner lamina, which therefore roofs in the germinal cavity and beyond the latter is in close contact with the white yolk. Whether this outer portion be first formed or the transformation of residual into endodermic cells proceed contrary-wise, from centre to circumference, has not been determined. In a bird’s-eye view of the germ at this stage are seen an area pellucida and an area opaca. The former is conterminous with the germinal cavity. The latter corresponds to the peripheric region of the germ, resting on the surface of the white yolk. Such a germ differs from a typical gastrula in that between its outer and inner lamine are included cells not derived from either. These are the cells of the “ middle-germ,” or mesoblast. Soon after the inner lamina can be distinguished, a dark spot shows itself, somewhat excentrically, in the clear area. This is the em- bryonal shield of von Baer. It is mainly due to a thickening of the outer lamina, and its appearance marks the development of the primitive streak, whose broadened cephalic border it represents. “The primitive streak owes its origin to an invagination of a part of the outer lamina. The part so invaginated is cut off. But it soon ceases to form one whole clearly separable from the cells of the middle- germ, wherein it becomes implanted. For here cells are associated which have a twofold origin, ectodermic and mesoblastic. Hence many of the contradictions into which discordant observers have fallen. [It is a pity that time did not permit Dr. Wolff to study the remarkable conclusions of the late Prof. Balfour on this subject.* | The floor of the primitive streak, thus reinforced by a copious con- tribution of cells from the middle-germ, Dr, Wolff terms the “ axial plate.” As the germ continues to grow, the axial plate gives rise to the rudiment of the cerebro-spinal system, the primitive vertebra with the lateral plates, and the chorda. The primitive groove and its boundaries are designated, in consequence, dorsal. Our author does not consider the medullary and primitive grooves as distinct formations, and denies the possibility of a displacement of one in front of the other. The peripheral portion of the axial plate extends into the opaque area. To this portion, chiefly, if not exclusively, derived from cells of the middle-germ, the phase “ vascular lamina” may con- veniently be applied. The accumulation of cells from the middle-germ about the ecto- dermic rudiment of the primitive streak is contemporaneous with * See Quart. Journ. Micr. Sci., xxii. (1882), p. 174, and this Journal, ante, p. 314, 760 SUMMARY OF CURRENT RESEARCHES RELATING TO (and results from) the disappearance of the peculiar marginal thick- enings which the blastoderm, since losing its lenticular figure, has hitherto presented. While the mesoblast coincided in extent with the ectoderm, it most abounded in the hinder and outer regions of the germ, being more sparingly manifest anteriorly and in the area pellucida. But with the formation of the primitive streak a rapid centripetal migration of the middle-germ ensues, and its cells retreat within the - limits of the clear area. Much confusion prevails as to the use of the phrases—marginal protuberance, germinal wall and germinal protu- berance. The “ Keimwall” of His belongs to the white yolk. It is identical with the “ Keimwulst” of Kélliker, which, however, the latter views as synonymous with the “ Randwulst” of Goette. But this lies wholly outside the white yolk, and is made up of the residual cells between it and the outer lamina. Remak first instituted the conception of germinal laminz as at present understood. [To a certain extent he was anticipated by C. F. Wolff and von Baer.] He was tolerably right as to his facts, but erred in his deductions. Unacquainted with the cleavage of the hen’s egg, he could not well appreciate its constitution before the formation of the ectoderm, nor could he perceive the significance of the germinal layers in the development of the higher animals generally. He describes the germ of the unincubated egg as made up of a firm outer and a more loosely constructed inner lamina. From the latter, as a first result of incubation, his alimentary glan- dular lamina separates by transformation of its cells. The residue of the inner lamina is now the middle lamina. Apart from this deriva- tion, at least nominally, of one germinal lamina from another, he finally has at his disposal a middle and an outer lamina but not an inner; since his first inner lamina is resolved into the middle and the alimentary glandular lamina, which latter alone he deems the earliest rudiment of a definite system of organs. Remak’s interpre- tation had many followers. They differ from him in words only who derive a middle lamina from his inner lamina and give this name to Remak’s “ Darmdriisenblatt.” It is all the same whether a splits from b, or b from a. This “ Darmdriisenblatt” is the inner lamina of Kélliker. What remains of the germ constitutes the outer layer, in Kélliker’s sense. From it, therefore, he derives his middle lamina, which is formed by the extension of masses of cells from the region of the primitive streak, on both sides of the germ, between its ectoderm and endoderm. Goette is right in describing a previous transfer of cells from the marginal protuberance, centripetally. But this wandering does not take place until after the formation of the inner layer. The migrating elements are cells of the middle-germ, and together with the cells of the primitive streak they make up the axial plate. The inner germinal stratum of Goette, which divides into his inner and middle laminz, is equivalent to the first inner lamina of Remak, who sometimes also designates this as the inner ‘“‘ Keimschicht.” Peremeschko, like Kolliker, is wrong in believing that in the formation of the ectoderm and endoderm the whole substance of the ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 761 germ is used up. He derives his mesoderm from large spherical elements, described by him as cleayage-spheres, which wander from the floor of the germinal cavity into the space between the primitive layers. These elements, the megaspheres of His, are when first evident merely the residual cells of the germ; at a later stage they are ageregates of cells whose nuclei and borders have become incon- spicuous through inception of yolk-granules. They are endowed with an extraordinary power of multiplication. The inner lamina, once formed, shuts off the rest of the germ from the germinal cavity, and by this time has received into itself the spheres in question, now for the most part resolved into their constituents, whose upward movement from the floor of the germinal cavity is due to their being specifically lighter than its contained fluid. His resolves the germ of the new laid egg into one lamina, the outer, designating the residual cells collectively by the not well chosen name of subgerminal processes. After the formation of the inner lamina there appears in connection with the primitive streak what he justly enough terms the intermediate stratum. His does not derive all the connective tissues from this stratum, but imagines a migration of cells from the white yolk, out of which the vascular system is developed. Until the appearance of the primitive streak the germ grows uniformly throughout. At its margin the outer and inner laminz make together an acute angle, between the legs of which, as seen in sections, cells of the middle germ are packed. As soon as the primitive streak is formed, these cells back towards it and become involved in the constitution of the axial plate. Thereupon the margin, deprived of its intermediate cells, appears asa solid keel, with three or four tiers of cells only, exclusively made up of the ectoderm and endoderm. While this peripheral region continues to spread itself, the under cells separate from the upper, of which only a single tier now remains in continuity with the outer lamina. Some of the separated cells at once assume the features of the cells,of the inner lamina (roofing the germinal cavity), as a prolongation of which they extend, beneath the outer layer, under the form of a thin membrane. This limiting membrane rests on the white yolk, but does not attain the extreme periphery of the germ. It there passes into an irregular mass composed of the other separated cells, which wander into the white yolk, become stellately branched, and anastomose to form a network whose meshes get filled with white yolk-spheres. Close to the margin of the germinal cavity, disappearance of the yolk-spheres changes this reticulum into a solid (polyderic) layer, passing gradually into the monoderic inner lamina. It can scarcely be doubted that all the cells between the outer lamina and the white yolk must be con- sidered as representing the endoderm peripherally. The reception of granules from the white yolk may be termed a sort of primitive digestion. Subsequently, when the vascular lamina grows into the area opaca, it is separated from the white yolk by the limiting (endodermic) membrane, and its first formed vessels take up the nutrient fluid which through this membrane they receive. Cells, 762 SUMMARY OF CURRENT RESEARCHES RELATING TO however, are not thus transferred. The cellular elements detected by Goette on the floor of the germinal cavity, and thence seen to wander, at an early period, into the germinal wall, must not be referred to the white yolk itself. Certainly the latter contains cells, but these, as above shown, have come from the cleaved germ, to which they return. The white yolk has no direct share in the formation of the embryo. It is well to be prepared with a definite answer to the question— what is a germinal layer? The cells constituting a primitive lamina must fulfil two conditions ;—they must arise directly from the germ, and possess their own peculiar properties. But two such lamine can be demonstrated, the ectoderm and the endoderm. We should not reckon as primitive layers either (a) the aggregate of residual cells (inner pro-embryonic layer of Goette = first inner lamina of Remak) which lies beneath the ectoderm of the egg before incubation or (b) the mesoblast, which consists, when first formed, merely of undiffer- entiated cells of the germ, after its ectoderm and endoderm have separated. The admission of the middle-germ to the rank of a funda- mental embryonic lamina renders impossible all attempts to settle the homologies of the primitive layers among the different classes of animals. But if we accept two primary layers only, this difficulty is removed at a stroke. Thus, in like manner, may we classify the tissues from an embryonic point of view. They are either simple or compound. The simple tissues are ectodermic, endodermic or mesoblastic. The compound tissues are formed by the union of cells from the middle germ, or their derivates, with cells from the ectoderm or endoderm. ‘This union is closer and takes place at an earlier stage of differentiation in the case of the striped muscle of vertebrate animals than with their cerebro-spinal system. We know that in some ccelenterates at least the muscular and nervous tissues are purely products of the ectoderm. There is still doubt as to the origin of many of the so-called endothelia. Dimensions of Histological Elements.*—-W. Krause gives a list (in 26 pp.) of the dimensions of the various histological elements, classified under different headings, such as Connective Tissue, Muscular System, Nervous System, &e. “Nervous System” (e. g.) is subdivided into Nerve Tissue, Spinal Cord, Brain, Peripheral Nerve System, and Nerve Endings, and the 1st subdivision is dealt with thus :— Nerve fibres, 0°0018-0-013 (Krause), 0°001-0°02 (Kélliker) thick. Olfactory fibres, 0:0038-0°0068 wide, 0°0018 thick. Nuclei, 0-0068-0-0113 long (Frey). Pale nerve-fibres, 0-0017—-0-0027 thick (Krause) ; (in Mammals) 0:0033-0°0056 wide, 0°0013 thick; Nuclei, 0:006-0-015 long, 0-0045-0:0067 wide (Kolliker), Medullated nerve-fibres and ganglion-cells are dealt out in a similar way. * Krause, W., ‘Nachtrage zum ersten Bande des Handbuches der Mensch- lichen Anatomie von C. F. 'T. Krause (3rd Aufl.).’ 8vo, Hannover, 1881, pp. viii. and 170 (1 pl. and +1 figs.). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 763 Influence of the External Medium on the Saline Constituents of the Blood of Aquatic Animals.*—L. Frédéricq points out that the water of the North Sea contains a little more than 3 per cent. of soluble salts, and has a marked salt and bitter taste; the blood of the Crustacea and Cephalopoda living in it has exactly the same taste, which leads to the supposition that it has the same chemical consti- tution; and this view is supported by chemical analyses. The blood of the crabs of the brackish water of Braeckman has a less salt taste, and that of the crayfishes of the Belgian rivers still less so. It would, then, seem to be certain that, in virtue of the laws of diffusion, there is a more or less perfect exchange of salts between the blood -and the external medium, and the seat of this process is probably the gills. But this variation in chemical composition, according to the characters of the external medium, would appear to be confined to the “lower animals” ; a similar diffusion might take place in fishes, but in them we find that the saline constituents of the blood are very different to those of the seas in which they live; an explanation of which may be found in the fact that the blood is in them much more isolated from the surrounding medium than it is in the invertebrate marine forms. B. INVERTEBRATA. Development of some Metazoa.t—lIn the third part of his studies on Comparative Embryology, E. Metschnikoff states that he finds that the identity between so called Archigastrule does not exist as Haeckel has supposed; nor must an Archigastrula be always bilaminate, for some very primitive forms contain mesodermal cells even during the blastula stage. Indications of a radial structure of the archigastrule have not been detected in the Echinodermata only; doubly symme- trical arrangements are not at first seen in the blastopore, and the elongated form of that structure must not, when found, be regarded as of palingenetic, but of adaptive origin. On the supposition that the radial gastrula form is the primary one, the question arises whether the gastrule of Echinoderms, and of such forms as Lineus and Polygordius, are really homologous ; if they are so it would seem to be a necessary consequence that the anus of the Echincpedia is the homologue of the pharyngeal orifice of the worm—a comparison with which the author is apparently dissatisfied. It is a question whether the Gastrea theory affords the promised key to the solution of morphological problems; the author points out that the formation of the endoderm, in many of the lowest Metazoa, by the appearance of separate cells in the segmentation cavity, can by no possibility be regarded as a compression of the process of invagina- tion, though, on the other hand, the invagination seen in the higher Coelenterata may quite easily be regarded as a shortened process. If we want to remain true to the Gastrea theory, we must suppose not * Bull. R. Acad. Sci. Belg., iv. (1882) pp. 209-12. j Zeitschr. f. wiss. Zool. xxxvii. (1882) pp. 286-313. 764 SUMMARY OF CURRENT RESEARCHES RELATING TO only that the head of the worm corresponds to the hinder end of the Echinoderm-larva, but that the mode of formation of the endoderm in the lower Metazoa has no phylogenetic significance. The so-called Acela will have to be regarded as degenerate forms, though they are neither parasitic nor sessile. All these difficulties may, however, be overcome by the supposition that the Gastrea does not represent the most primitive form of Metazoa, but a later stage which succeeded upon that of Metazoa without a digestive lumen, and with an internal digestive parenchyma. From this point of view the parenchymatous larve of sponges and hydroids, as well as the lowest accelous Turbellaria, must be regarded as being closely allied to one another, and as repre- senting the oldest Metazoa. It was not till later that there were developed from them animals with a differentiated enteric canal, like the hydroid polyps of the present day, where we see repeated the most important phylogenetic phases (migration of endodermal cells, formation of a solid parenchyma, and later development of an enteric lumen). The earlier development, in the course of time, of the endoderm may be compared to the early formation of such organs as the vertebrate notochord, and the change in time may well be allowed to have exercised a not unimportant influence in the process of gastrulation, and the large blastopores of some forms may be best ascribed to adaptive modification; to this also would appear to be due the appearance of several gastrula stages in the development of one and the same animal form. In conclusion it is pointed out that, while in some cases we have this hypergastrulation, in others there are formed pseudo- gastrule, that is, stages similar, but not exactly corresponding to gastrule. Here may, perhaps, be ranged EH. van Beneden’s rabbit- gastrula, or his Dicyema, while an interesting example is to be found in the Cyclostomatous Polyzoa, the gastrule of Barrois being in fact preceded by a much earlier stage in which the endoderm is really formed. The author’s notes on Discoporella radiata bring to an end a most suggestive essay. Symbiosis of Dissimilar Organisms.*—G. Klebs here discusses symbiosis with mutual adaptation, which is generally represented by forms which are very widely separated, and often belong the one to the animal and the other to the vegetable kingdom. Instances are cited both among plants and animals; among the latter the corals are perhaps as remarkable as any, and here we frequently find that while the guest is dependent on the coral, the latter does not seem to re- quire the guest; when, however, it is present, it may lead to very considerable modifications in the form of its partner. The specific characters of Heteropsammia michelini are to be referred directly to the presence of an Aspidosiphon. Another set of relations is well shown by the case of the crab Pagurus prideauxii and the Actinian Adamsia palliata; when the former changes its shell, it seizes on the anemone by its chele and carries it off to its new home. The latter is completely adapted to * Biol. Centralbl,, ii. (1882) pp. 385-99. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 765 its mode of life, for it has two pedal lobes which become firmly attached around the orifice of the shell, The Actinian would appear to seize and strike smaller marine animals by its stinging cells, and these would thus come into the area of the sedentary crustacean. Like other writers on this subject at the present time, the author directs his notice to the yellow cells found in the Radiolaria. Pelagic Fauna of Fresh-water Lakes.*—Professor F. A. Forel considers that Entomostraca alone show the peculiar character of pelagic animals, the pelagic fauna in its general features being similar in all the countries and lakes of Europe yet investigated, though seldom represented in any one lake by all the animals of the fauna. The characters common to the animals of the pelagic region are due to their mode of life. They must swim incessantly, and there- fore, instead of any organ of adhesion, they have a highly developed natatory apparatus ; they are sluggish, and escape their enemies by their nearly perfect transparency, which may be regarded as a mimicry acquired by natural selection, only those having held their own which are as transparent as the medium in which they live. They perform daily migrations, during the night swimming at the surface, and in the day descending into the depths. As to the origin of the pelagic fauna, the author decides that certainly the palustrine or fluviatile Entomostraca have not become transformed in each lake into pelagic species or varieties. The almost complete identity of the Huropean pelagic Entomostraca shows a common origin and distribution, and he believes that we must find the cause of the differentiation of the pelagic fauna in the combination of two different phenomena—the daily migrations of the Entomos- traca, and the regular local winds of the great lakes. On the borders of great masses of water two winds prevail, one blows at night from the land to the water, the other by day from the water to the land. The nocturnal animals of the shore-region which swim at night at the surface are at this time driven towards the middle of the lake by the surface-current of the land wind, sink during the day (being driven away by the light into the deep water) and thus escape the surface- current of the lake-wind, which would otherwise have carried them again to the shore. Constantly driven further every night, they remain confined to the pelagic region, as they are not carried back again during the day. Thus a differentiation takes place by natural selection, until at last, after a certain number of generations, there remain only the wonderfully transparent and almost exclusively swimming animals which we know. When this differentiation has once taken place, the pelagic species is conveyed by the migratory water-birds from one country to another, and from one lake into another, where it reproduces its kind if the conditions of the existence of the medium are favourable. In this way we may find the pelagic Entomostraca in lakes which are too small to possess the alternation of winds, the animals having been differentiated by the action of the winds in other larger lakes. * Biol. Centralbl., ii. (1882) pp. 299-305. Ann. and Mag. Nat. Hist., x. (1882) pp. 320-5. Ser. 2.—Vot. IT. 3 °F * 766 SUMMARY OF CURRENT RESEARCHES RELATING TO In this way we can easily explain the differentiation of most pelagic species, with the exception of Leptodora hyalina and Bytho- trephes longimanus, which are not related to the other fresh-water species, and for which we must, therefore, seek a marine origin. Bythotrephes would be derived from an ancestor which was common to it and to Podon, its nearest ally. Leptodora, on the contrary, according to Weismann’s view, would have branched off from a primeval Daphnid, of whose direct descendants nothing further is known. But how could the passage from salt to fresh water be effected ? Pavesi supposes the closing of a fjord, and its gradual conversion into a fresh-water lake. This is possible; but for the definite deci- sion of the question we have still no reliable materials. So soon, however, as the adaptation to fresh water had been effected, the dis- tribution of these forms of marine origin took place in the same way as with other pelagic fresh-water forms, and thus these two forms would be introduced into lakes which were never in direct communi- cation with the sea. Professor H. N. Moseley also delivered an address * on “ Pelagic Life” (Fauna and Flora), at the Southampton Meeting of the British Association, which constitutes a highly interesting summary of our existing knowledge on the subject. Mollusca. Curious Secretion in Gasteropods.—The parts termed salivary glands in prosobranchiate gasteropods are far from being sufficiently understood; they offer a tempting subject of research to young in- vestigators. In particular is this the case with Dolium galea, the largest gasteropod of the Mediterranean. Poli was the first to notice the cesophageal organs of this mollusc. Keferstein has given an original description and figure of the whole apparatus in Bronn’s ‘Thier-reich.’ Troschel noted the very acid “saliva” of Dolium, in which Boedecker found by analysis a large percentage of SO,H,. De Luca and Panceri confirmed his results, obtaining more than 3 per cent. of free sulphuric acid. They also observed that much carbonic acid was given off when the freshly excised “ glands” were placed in contact with the air, and further showed that other prosobranchs, as well as Aplysia, likewise yielded free sulphuric acid. They especially indicated the enormous size of the “glands”; in a Doliwm whose total weight was 1305 grammes, the shell weighed 550 and the “ olands” 150 grammes. Hoppe-Seyler remarks that a secretion so wonderfully composed as that of Doliwm has nothing in common with ~ the saliva of the higher animals. Another eminent physiological chemist, Dr. R. Maly, has lately studied this “saliva” and expresses similar doubts. He finds that, added to alkaline neutral or acid solutions, together with albumen fibrin or starch, it digests none of these substances. Neither could he detect any ferment in the * ‘Nature,’ xxvi. (1882) pp. 559-64. + SB. K.K. Akad. Wiss. (Wien), Ixxxi. (1880) p. 876, and Monatsb. f. Chem., i. pp. 205-15. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 767 “ olands” themselves. He concludes that this acid fluid is of no use to the animal when once secreted, and he again directs attention to the peculiar structure of the so-called glandular organs, which much need a thorough re-examination. Olfactory Organ of Parmacella.*—H. Simroth, dealing with the olfactory organ of this terrestrial pulmonate gasteropod, and with the question whether there is any relation between the olfactory sense and respiration, points out that the pulmonary tissue is extremely well developed, and that from the anterior edge of the respiratory space there extends into the mantle-cavity a shallow groove, bounded by two distinct ridges ; these are in length at least equal to that of the transverse diameter of the body, they are richly provided with ganglion-cells, and traversed by bundles of muscular fibres. There can, then, be no doubt that we have here a sensory organ, and that that organ is olfactory in function. Another question which arises is as to the homology of this part with the olfactory organ of aquatic gasteropods. The position and mode of innervation of the organ makes this very doubtful, and, taken in conjunction with the systematic position and life-history of the possessor, leads us to think that we have here to do with a recently acquired structure. Innervation of the Mantle of Lamellibranchs.t—L. Vialleton has studied Unio and Anodonta by removing the mantle from its attachments in a living specimen, and placing it for 15 minutes in lemon juice, and then for about 20 in a 1 per cent. solution of chloride of gold. Feebly acidulated water is added, and, after 24-36 hours’ maceration, the examination may be entered upon. In the portion of the mantle situated within the pallial impression, the nerves are found to be especially distributed along its two faces, a little below the epithelium; from their mode of union there result nodal points of varying form, and a plexus presenting spaces differing in shape and size; from each superficial plexus there are given off finer fibres, which either arise directly from larger nerves or from the finer branches of them; they finally divide into ultimate fibrils which form a closely-set subepithelial plexus. The whole arrange- ment may be compared to that which is found in the connective tissue of the cornea of the human eye. Observations on allied forms lead the author to believe that this arrangement is common to all Lamelli- branchs. Differentiation of Protoplasm in Nerve-fibres of Unionide.{— In investigating this subject, J. Chatin, after treating with osmic acid, teases the nerve-fibres of Unio pictorum, Anodonta cygnea, &c., stains with carmine or anilin red, and mounts in glycerine. The axis of the fibre consists of a bundle of fibrils longitudinally arranged ; around this bundle lies a protoplasmic layer containing nuclei here and there, but difficult to observe. The protoplasm is finely granular ; * Zool. Anzeig., v. (1882) pp. 473-5. t+ Comptes Rendus, xciv. (1882) pp. 461-3. { Ibid., pp. 1723-6. ares 768 SUMMARY OF CURRENT RESEARCHES RELATING TO it contains spheroidal refringent myeloid globules, coloured black by osmic acid; they multiply rapidly, but remain distinct and are com- parable to the myelin of Vertebrata. Pigment-granules of a brownish or yellowish colour, found in some ganglia, are often seen in the pro- toplasm of the nerves; they are not altered by ether or chloroform. Transverse sections of the nerves show this protoplasmic layer to constitute the entire covering of the central fibrils, and to be approxi- mately homogeneous in density throughout; although a slightly denser external zone is somewhat constant in its occurrence, it is not dense enough to be comparable to the Schwann’s sheath of the Verte- brate nerve. Molluscoida. * Disdaplia.*—A. Della Valle, in describing this new genus of the Synascidie, states that the tail of the larva presents the following constitution: there is an envelope of cellulose, with amceboid nuclei, a membrane continuous with the ectoderm, which is formed of large, flattened epithelial cells, a contractile layer of fusiform cells which are transversely striated, and the axis of the tail, which is more - transparent than the rest, and is occupied by the hyaline cylinder, which is, according to some, a solid cartilaginous notochord; the author, however, like some other writers, finds that this axial struc- ture is a hollow tube, the wall of which is continuous with that of the peritoneal sac. Attention is to be directed to the fact that the first buds which are developed in a young colony have no sexual glands, but those that are derived from the later colonies (due themselves to the repeated fission of the primitive buds) present at once indications of these glands, or ‘at least of groups of cells which will develope intothem. The author promises to prove in a later work that this phenomenon is not peculiar to Disdaplia, but is to be seen in other Synascidians. Natural History of Doliolum.j—B. Uljanin concludes that, in the developmental cycle of Doliolum, only two generations succeed one another; one of them is developed from the egg, is provided with a stolo prolifer, and gives rise to a generation of nurses; the other is derived asexually from the stolon, and this latter generation is poly- morphous; the separate forms which constitute it have hitherto been — regarded as special generations, and distinguished as lateral buds, median buds (second generation of nurses), and sexual forms; of these, the two former have rudiments of reproductive organs, which disappear during the course of development. Doliolum may be looked upon as a form which has inherited a process of alternation of generations from the Synascidie and Pyrosomide, and in which, owing to a slow diminution in the amount of nourishment, the nurse developed from the ovum has gradually been subjected to a series of adaptation, for the purpose of the preservation of the species. The want of true colonial life has diminished the amount of gemmation * Arch. Ital. de Biol., i. (1882) pp. 193-203. + Zool. Anzeig., v. (1882) pp. 429-36, 447-53. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. . 769 and the thickness of the protecting mantle, which is here merely a feebly developed hyaline layer, derived from the ectoderm and without any special cells. Development of Ganglion and Ciliated Sac in Pyrosoma.*— The ciliated sac, or “ olfactory organ,” has been studied by L. Joliet in the bud of this Tunicate. The walls of its canal consist of a cubical non-ciliated epithelium, a few cilia and flagella occurring, however, at the point at which it opens into the branchial sac; the median tubercle is composed of a mass of small round cells, grouped round a diverticulum of the canal. The organ evidently represents the canal of the gland of the Ascidians proper, the anterior ciliated part corresponding to the “ pavillon,” and the median tubercle being apparently a rudimentary gland. Kowalewsky is wrong in speaking of a cavity within the ganglion, and of the obliteration of the cavity of the primitive neural canal, for he has mistaken the latter for the ganglion. The canal is constricted at each point at which a young bud is given off, and thus forms a pear-shaped vesicle within each older zooid, and its walls undergo modifications. From its hinder end, which thickens, some round cells between the vesicle and the ectoderm are detached ; these cells proliferate actively, and form an oval mass which grows round the posterior end of the vesicle, constituting the true ganglion in almost its adult form. The vesicle opens into a depression in the branchial sac, and becomes the ciliated sac of Huxley. Probably the neural canal of Ascidian larve also, of which the cerebral vesicle is a part, is only the rudiment of the canal of the subneural gland. The function of the canal in question is probably olfactory, a supposition favoured by its direct apposition against the ganglion; it is at any rate not excretory, as the ciliary currents set towards the bottom of the sac and not towards the exterior. Development of Genital Products of Cheilostomatous Bryozoa.t —W.J. Vigelius has found a very suitable object for study in the arctic species Flustra membranaceo-truncata, where he finds that the ovary arises from the inner surface of the endocyst, and from that portion of the wall of the distal half of the zocecium which lies opposite to the side which carries the operculum. Each ovary forms a small spherical or ellipsoidal body of a yellowish colour, which consists of a number of small, round, closely-packed cells. Although apparently isolated, it is connected with the endocyst, the small cells of which take part in its formation. A differentiation is soon seen in the primitively similar elements, for two (or, rarely, more) become distinguished by their size; the other cells become set around these two ova, and the growth of ‘the latter is accompanied by an increase in the size of the follicle, the cells of which apparently increase by division. When the ovarian cells have attained a certain size, there commences a struggle for existence. One grows more rapidly than the other, and the less fortunate one is driven to the periphery of the ovum, where it ceases to grow, although still quite distinctly an ovarian cell; * Comptes Rendus, xciv. (1882) pp. 988-91. t Biol. Centralbl., ii. (1882) pp. 485-42. 770 SUMMARY OF CURRENT RESEARCHES RELATING TO where there are more than two ova in one follicle, the same pheno- menon obtains, one only continuing its further development. About this time the ovary lies free in the perigastrie cavity. Soon the yolk of the eggs becomes darker and granular, and frequently so contracts that a peripheral space is left between it and the egg-wall; as the nutrient material is used up, the central portion of the follicle gradually becomes clearer and thinner, and by the absorption of the cells a passage is left for the egg. The free ege is rounded or oval, and is generally of some size; its passage into the brood-capsule is probably effected by muscular contractions. The author comes to the conclusion that fertilization does not take place in, but externally to the ovicells. Hermaphrodite zocecia were rarely observed ; but when they were, the arrangements were such as to point to self-fertilization. The eggs would seem to be developed independently of the polypides. The testes appear to be developed later than the ovaries, and not at a definite point of the zocecium ; they are irregular in form, and consist of masses or cords of rounded darkly-pigmented cells, very similar in appearance to those of the primitive ovaries; the male zocecia are less numerous than the female. The author thinks that there can be no doubt that the Bryozoa have a general phylogenetic relation to the Rotifera, Mollusca, Chetopoda, and Gephyrea (the Trochosphere-larva, Balfour); in their oogenesis they have most marked resemblance to the Cheetopoda and Gephyrea. Arthropoda. Brain of Crustacea and Insects.*—J. Bellonci, in an account of the nervous system of Spheroma serratum, whose brain appears to be intermediate between that of Decapod Crustacea and that of Insects, insists on what Berger and Claus have already shown, viz. that the lateral enlargements of the brain of the higher Crustacea are not, as Diet] supposed, the optic lobes, but that the optic ganglion is the true optic centre and altogether corresponds to the optic lobes of insects. In fact, in Spheroma, as in Nephrops, the lateral swellings of the median cerebral segments are the centres of origin for delicate fibrils which belong to the antennary (interior) nerves, and they correspond, both in relation and structure, to the antennary swellings of the brain of insects. So again, in Crustacea just as in Insects, the fibres from the optic lobes penetrate between these swellings and the superior lobes: and, if we consider that the swellings of the nerve of the external antenne are formations peculiar to the Crustacea, we see that in them the lobes containing the olfactory “ glomeruli” have just the same relations to the cesophageal commissure as the same parts in insects. The parts which, in the Crustacea, are really homologous with the fungiform bodies of insects are the internal lobes of the superior cerebral segment. The author supports his views by an account of the structure of the brain of Gryllotalpa ; at the same time he recognizes the marked * Arch, Ital. de Biol., i. (1882) pp. 176-92. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 771 differences in the size and histological constitution of these regions which point to a much more elevated psychical function in insects. The great development of the swellings of the median cerebral segment in the higher Crustacea indicates that this region is very important from a psychical point of view. The further details of the structure of the brain and sensory organs of Spheroma would require a number of figures for their satisfactory elucidation. a. Insecta. Want of Cutaneous Absorption in Aquatic Coleoptera.*— L. Frédéricq placed Dytiscus marginalis and other water-beetles in aqueous solutions of curare, or strychnine, a few drops of which were sufficient to poison a frog in a few minutes. The insects, however, lived in them for from 15 to 30 days, when the experiment was brought to an end. It is to be noted that Coleoptera may be poisoned by strychnine or curare, and the facts observed agree with the statement of F. Plateau that aquatic Coleoptera do not suffer from immersion in sea-water. Habits of Ants, Bees, and Wasps.—Sir John Lubbock recently laid before the Linnean Society his tenth communication on this subject, containing an account of his further observations made during the past year. The two queen ants which have lived with him since 1874, and which are now, therefore, no less than eight years old, are still alive and laid eggs last summer as usual. His oldest workers are seven years old. Dr. Hermann Miiller, in a recent review, had criticized his experiments on the colour-sense of bees; but Sir John pointed out that he had anticipated the objections suggested, and had guarded against the supposed source of error. The diiference was, moreover, not one of principle, nor does Dr. Miiller question the main conclu- sions arrived at or doubt the preference of bees for blue, which, indeed, is strongly indicated by his own observations on flowers. Sir John also recorded some further experiments with reference to the power of hearing. Some bees were trained to come to honey which was placed on a musical box on the lawn close to a window. The musical box was kept going for several hours a day for a fort- night. It was then brought into the house and placed out of sight, but at the open window, and only about seven yards from where it had been before. The bees, however, did not find the honey, though when it was once shown them they came to it readily enough. Other experiments with a microphone were without results. Every one knows that bees when swarming are popularly (and have been ever since the time of Aristotle) supposed to be influenced by clanging kettles, &c. Experienced apiarists are now disposed to doubt whether the noise has really any effect; but Sir John suggests that even if it has, with reference to which he expressed no opinion, it is possible * Bull. R. Acad. Belg. Sci., iv. (1882) pp. 212-3. 172, SUMMARY OF CURRENT RESEARCHES RELATING TO that what the bees hear are not the loud, low sounds, but the higher overtones at the verge of or beyond our range of hearing. As regards the industry of wasps, he timed a bee and a wasp, for each of which he provided a store of honey, and he found that the wasp began earlier in the morning, and worked on later in the day. He did not, however, quote this as proving greater industry on the part of the wasp, as it might be that they are less sensitive to cold. Moreover, though the bee’s proboscis is admirably adapted to extract honey from tubular flowers, when the honey is exposed, as in this case, the wasp appears able to swallow it more rapidly. This particular wasp began work at four in the morning, and went on without any rest or intermission till a quarter to eight in the evening during which time she paid 116 visits. = Larve and Pupe of Diptera.*—In continuation of a former memoir,t Head-forester Beling describes the metamorphoses of 39 species of flies belonging to the families Tabanide, Leptide, Asilidz, Empide, Dolichopide and Syrphide. He concludes by giving an analytical table, occupying four pages, in which the characters of the larvee of 21 genera are contrasted in accordance with the dichotomic method. Organs of Flight in Hemiptera.t—L. Moleyre prefaces a state- ment of the result of his observations by pointing out that in most Hemiptera the part played by the anterior and posterior wings during flight is almost equally important. But the former (hemielytra) are usually horny, whilst the latter remain quite membranous. Hach of the two pairs of wings having a distinct structure and capacity, it is indispensable that they should supplement one another and that perfect solidarity should exist between them in their different move- ments. The apparatus which serves to attach the wings to the hemi- elytra consequently acquires, from a physiological point of view, exceptional importance. Accordingly he has undertaken an examina- tion of its conformation in the different groups of Hemiptera. In the Cicadide the connecting apparatus is simplest. In them, as well as in Fulgora and some allied genera, the posterior margin of the hemielytron is folded underneath, starting from the middle, a deep furrow being formed, in which, at the moment of flight, a correspond- ing fold of the wing fits. In Fulgora the folded portion of the wing begins to be differentiated. In the Membracide, the Cercopide, and the Iasside, the fold is reduced to a sort of plate inclined backwards on the plane of the wing, often bent into a semicircle and furnished at the extremity with fine serrations. In the sub-order Heteroptera, it is the fold of the hemielytra, and not that of the wings, which is differentiated. There is also a con- necting apparatus which is only found in certain families of Homoptera. In the groups where it attains its greatest development, it appears to * Arch. f. Naturgesch., xlviil. (1882) pp. 187-240. + Ibid., xli. (1875). {} Comptes Rendus, xey. (1882) pp. 349-52. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 773 be independent of the principal apparatus, and seems to act under special conditions, In the Cercopide, whose wings present at the base of the anterior margin a triangular enlargement, the external side of the triangle is armed with a row of hooks, few, but very strong, whose extremities, sharply bent, are directed backwards. These hooks are also seen in the Tettigoniide and in Ledra where they are very small. In some Membracide there are vestiges of these hooks in the shape of long straight hairs, inclined backwards. It is important to note that in Ihelia expansa, which has only two or three of these hairs, they occupy the widened region of the edge of the wing. In Cicada and Fulgora, the principal connecting apparatus is con- tinued as far.as the base of the wing by a sort of marginal nervure, forming a very strongly marked rim. Many of the Hemiptera fly but rarely; the flight of the Hymen- optera, more powerful and better directed, is therefore much more sustained, and from this comparison most naturalists seem to conclude that the organs of flight in the latter exhibit the highest degree of perfection. The author thinks, however, on the contrary, that the double function of the hemielytra, which serve at the same time both as wings and for sheaths, involves special complication in the form of the organs of flight. B. Myriapoda. Diversity of Type in Ancient Myriapods.*—S. H. Scudder dis- cusses the systematic position of Palcocampa (Meek and Worthen), and comes to the conclusion that it is neither the caterpillar of a lepidopterous insect nor a worm, but a myriapod of a new and strange type. This brings us face to face with two remarkable facts: First, that in this ancient myriapod, carrying us back as far as any traces of wingless tracheate arthropods have been found, and therefore presum- ably not far from the origin of this form of life upon the earth, we find dermal appendages of an extraordinarily high organization, more complicated than anything found in living arthropods, excepting the more varied scales of several orders of hexapods; a form of appendage which it would seem, on any genetic theory of development, must have required a vast time to produce, but which we now seem to find at the very threshold of the apparition of this type of arthropod life. Second, that at this early period, in marked contrast to what we find in other groups of articulated animals, the divergency of structure among myriapods was as great as it is to-day. The structural rela- tions of myriapods and hexapods render it probable that the former preceded the latter ; and in complete accordance with this expectation, the structural relations of the oldest fossil myriapods indicate their apparition at a period earlier than that to which the winged insects are hypothetically assigned. This would compel us to consider the earlier type as aquatic, for which we have presumptive evidence in * Amer. Journ, Sci., xxiv. (1882) pp. 161-70. 774 SUMMARY OF CURRENT RESEARCHES RELATING TO the structure of the Euphoberide, and renders it all the more sur- prising that the penetrating researches of the last thirty-seven years, since the first Carboniferous myriapod was discovered, have not yielded the slightest trace of fossil myriapods below the coal-measures. This discrepancy between fact and hypothesis should, the author considers, stimulate to more searching investigations, particularly of those articulates of the older rocks whose aftinities have not been satisfactorily settled. y- Arachnida. Observations on Scorpions.*—Professor Ray Lankester finds that in the scorpions there exists a similar pair of large coxal glands, having essentially the same structure and position as the coxal glands of Limulus. It does not seem possible to doubt that these are homo- logous structures. Though no external opening has been found as yet, in either the one case or the other, it is possible that such an opening exists. Though glands in a similar position (at the bases of the limbs or jaws) are found in other Arthropoda, there are none known which agree so closely in position and structure with either the coxal glands of Limulus, or of Scorpio, as these do with one another. Possibly such coxal glands are in all cases the modified and isolated repre- sentatives of the complete series of tubular glands (nephrida) found at the base of each leg in the archaic arthropod Peripatus. The discovery of the existence of such corresponding organs goes a long way towards confirming the conclusion as to the close affinity of Scorpio and Limulus to which Professor Lankester had been led by the observation of numerous other structural coincidences. Professor Lankester also adds a note} on the differences in the position of the ganglia of the ventral nerve-cord in three species of scorpion, in which he shows that an important anatomical difference obtains between the scorpions with triangular sternum (Androctoni) and those with pentagonal sternum (Huscorpii, Buthi, &c.). Whether the scorpions with bandlike sternum (Telegoni) differ from or agree with either of these types in respect of their nervous system, has yet to be discovered. Insecticolous Acari.t—A. Berlese first deals with Hypopus, and confirms the doctrine of Mégnin that these animals are heteromorphous nymphs of other Sarcoptide, and the same seems to be true of Homopus, Trichodactylus, and others ; the pedunculated Uropoda are shown to be nymphs, and it is laid down that no Uropod can be judged to be adult until the presence of the genital operculum has been demonstrated. A number of adult Acari may attach themselves to insects, but, as a general rule, these migratory forms are not adult. Migration would appear to be determined by desiccation and starvation, and insects to be the principal agents in the rapid and extended diffusion of the Acari. * Proc. Roy. Soc., xxxiv. (1882) pp. 95-101 (1 fig.). + Ibid., pp. 101-4 (3 figs.). + Arch. Ital. de Biol., i. (1882) pp. 279-81. ZOOLOGY AND BOTANY, MICROSCOPY, ETC, Tio Sense-hairs of the Hydrachnida.*—Dr. G. Haller has obtained the material for his investigations from the Lake of Geneva, a locality which has already t added considerably to our knowledge of the systematic zoology of the group. Olfactory hairs—In Atax the long hairs of the first pair of legs occur chiefly on the lower and outer surfaces of the 2nd, 3rd, 4th, and 5th joints, and diminish in length towards the latter joint. They are sword-shaped. Almost all of them are inserted within certain excavated eminences of considerable size, which protect the base of the hair, while allowing of its free movement, and contain the ganglion from which proceeds the nervous twig which supplies the hair. The hair is traversed by a central cavity which opens to the exterior near the point by an extremely attenuated canal; a num- ber of similar fine canals leave the central cavity, and open at the extremities of some fine teeth which fringe the posterior side of the hair. The function is probably olfactory, and thus the first pair of legs in Ata is equivalent physiologically to an antenna. Similar hairs occur in Awona, and on the two hind pairs of legs, as well as on the first, in Ata itself. Scales and tactile hairs—On the hinder and interior surfaces of the palps, where these hairs are absent, they are replaced by certain scales and tactile hairs. The former are very widely distributed among the Acaride, and in some Oribatide occur over the whole body as well as the extremities, or they may be confined to the body or to certain parts of it, or, as in Afax, to the extremities. In Atax crassipes they occur only in the first pair of legs, at considerable intervals, on the 2nd to the 5th joints; they have a lancet-like shape ; the cavity branches and opens in the same way as that of the olfactory hairs, although in Atax the margin does not present the same thorn- like points for the canals to open into. Nerves have been observed in connection with the canals. The function of the scales is probably also olfactory. Of the tactile hairs, already described by Haller elsewhere, two new forms are described. The hook-shaped form ends in a fine head, and is now stated to be connected with a nerve-fibre. The length and thickness remain constant in the same species, but vary enormously in different Acarids, the long and stout bristles of the ultimate and penultimate joints in the two anterior limbs of the Dermaleicht and Atax, and the short and weak hairs of the penultimate joint of the maxillary palps, being referable to the same type; a ring of very short hairs surrounds the margin of the body of Uropoda clavus. The second form of tactile hair occurs only in a representative of a new genus, Forelia, from the Lake of Geneva; it occurs exclusively in the male, and is aggregated in large quantities, covering consider- able areas; it may be either a short, slightly curved hair on a small chitinous eminence which is penetrated by a nerve-fibre, or such a hair may be accompanied by another of about half its length ; locality, the end of the foot of Ataz. * Archiv f. Naturges., xlviii. (1882) pp. 32-46 (1 pl.). t See Lebert’s researches, this Journal, iii. (1880) p. 69. 776 SUMMARY OF CURRENT RESEARCHES RELATING TO The antenniform hair of Hydrachnida occurs at the anterior end of the body or, less frequently, on the back, in front of the insertion of the first pair of legs. It is very mobile, and is placed on a small eminence which is hollowed out so as to form a complete socket for its base; morphologically, it evidently represents the weak hairs which lie at the sides of the orifices of the cuticular glands of the back, as the duct of one of these glands opens close to it. The central canal does not send out fine tubes to the surface, as in the case of the olfactory hairs, but ends blindly; hence the function is probably simply tactile. An auditory function is assigned, chiefly by a process of exclusive reasoning, to some very simple long bristles, pointed and pale in colour, which occur at long intervals on the legs. In Hylais a dagger- shaped hair with delicate fringing filaments clothes in great abun- dance the space between the epimere of the first four legs; it is supplied by a nerve on which a ganglion is placed within the ring which surrounds its base. Some stout, short hairs, placed on the upper edge of the labium in Hydrodroma rubrum, &c., resemble tactile organs, but are possibly, from their position, gustatory. The spined elevation of the lower side of the second joint of the palp of Limnesia is, probably, simply intended to meet the opposed claw of the mandible, and is not specially sensory in its properties. The chitinous nail-like tips of the palps of the species of this order, must also be regarded only as grasping organs. 6. Crustacea. Ontogeny of Fresh-water Copepoda.*—J. A. Fric gives (in some- what difficult French) a preliminary note on the ontogeny of fresh- water Copepods, principally confined to the genera Cyclops, Diaptomus, and Canthocamptus. Although it might be thought there was no room for further work in the apparently exhausted field of the anatomy and development of the Copepods, he found on the contrary a considerable number of facts hitherto unexplained. The nervous system (brain, oesophageal collar, and ganglionic chain) and the alimentary canal are discussed in detail. In regard to nutri- tion and circulation the author refers to the fact that in this respect the Copepeds formed an exception, hitherto unexplained, amongst the Crustacea. The nutritive liquid is set in motion, as is known, either by the heart, or by the regular alternations of the alimentary canal, in cases where the heart is not developed. But the blood-corpuscles, which are so numerous in the Phyllopods, have not, until now, been observed in any Copepod. Claus himself says, “It is remarkable that cellular elements (in the blood) are wanting, whilst they appear in such abundance in the allied Daphnide, and I have never been able to see blood-corpuscles even in the large, transparent, marine species.” It is now easy to understand why the lymphatic corpuscles have not been observed in the Copepods: they do noé exist in the usual * Zool. Anzeig., v. (1882) pp. 498-503, ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 777 form—forced in a mass with the nutritive liquid through the plexuses of the body—but they glide almost in the form of parasitic amcebe over the muscles and the organs, nourished by the liquid of the body. In this form the author has observed them in Cyclops without a heart, as well as in the Calanide (Diaptomus) which have one; it is therefore very probable, or even certain, that they exist in the whole of the Copepoda. They are mesoblastic cells in movement during the whole of life, which participate, from their earliest stages, in the formation of the muscles and genital canals. It is proposed to divide the genus Cyclops into two natural groups. The principal differences exist in the larval states of the nauplius and metanauplius, in which the characters are so different and so marked at first sight, that the possibility of a mistake is entirely excluded. The principal difference consists in the organization of the limbs. In one of these groups—the Dolichopoda—which is evidently the oldest, all the limbs serve for locomotion, and only a few spines on the second and third pairs are for seizing nourishment. The second group—the Brachypoda—on the contrary is more perfectly organized ; it is especially the third pair which is bent in the form of maxille and adapted exclusively for seizing nourishment. The spines also, at the base of the antennz of the second pair, are adapted for this function. Whereas in the first group all the limbs extend far beyond the margin of the body, and the third is furnished with a long natatory branch, in the other group they are very short and robust, with the natatory appendage on the mandible very rudimentary. Aberrant Oniscoids.*—The wood-lice are much neglected by English naturalists. They are well worthy the attention of micro- scopists who are not able to visit the seaside, and yet desire some path of inquiry affording more promise than the beaten anatomical tracks. As a sample of what may be done in this direction we note a memoir by Dr. Max Weber on Haplophthalmus and Trichoniscus, genera enrolled in the exceptional sub-family of Trichoniscide. The structure of Trichoniscus, save in regard to externals, had not before been investigated. The copious details which such an essay contains must necessarily be studied in the original. Points of general interest, affecting other isopods, are duly indicated. Dr. Weber makes a digression, more than eight pages long, on the subject of chromatophores. Leydig first showed that in the same situations as chromatophores are found cells without pigment, but otherwise similar, the whole forming one common system. Also animals of constant tint possess non-contractile cells, presumably homologous with chromatophores. Nerves are unquestionably distri- buted to the chromatophores. By means of gold chloride Dr. Weber has proved this connection in the case of a common isopod (a young Philoscia). Anger, fear, love and other emotions undoubtedly cause animals with chromatophores to change colour; yet it is usually assumed that the play of the chromatophores serves to hide their possessor, and perhaps in some cases for protection. But Leydig saw * Arch, f. Mikr. Anat., xix. (1881) pp. 579-648 (2 pls.) 778 SUMMARY OF CURRENT RESEARCHES RELATING TO tree-frogs, amid their natural surroundings, change spontaneously their beautiful green for a dirty grey tint, just as they are known to do in captivity, especially during murky weather. The inference follows, that a depressed temperature here acts on the chromatophores, particularly when we consider that these organs are an appanage of peecilothermous animals. We learn from v. Platen, Moleschott, and Fubini, that light acting directly on the skin (apart from what is termed the chromatic function, or the indirect influence of light through the eyes) enhances the metamorphosis of tissue. Dr. Weber concludes that one use at least of the chromatophores is to diminish the transparency of the skin, and thus lower the action of even moderate light when it begins to affect injuriously the organism. Blind Subterranean Crustacea in New Zealand.*—The existence of blind Edriophthalmatous Crustacea in wells and subterranean cave- rivers in Europe has long been known, and now Mr. C. Chilton describes some new forms found in New Zealand. They were obtained from a well at Eyreton, about six miles from Kaiapoi, North Canter- bury ; the well had been excavated about seventeen years previously, was not more than twenty-five feet deep, and was fitted with a common suction-pump through the medium of which these new forms were obtained. These proved to be three species of Amphipoda and one of Isopoda. In none were there to be found in either the living or recent specimens the least trace of eyes. The isopod is referred to anew genus Oruregens, and is most remarkable from the fact that it has only six pairs of appendages to the seven thoracic segments, whilst the normal number should be seven. In many isopods the young have at first only six pairs of legs, the last thoracic segment being but slightly developed and destitute of appendages, and hence at first sight it might appear that the new form was but an immature state. Mr. Chilton, however, states that he has examined altogether twenty live specimens, none of which seemed otherwise to have anything immature about them, and these were obtained at various times from January to October 1881; he would, therefore, refer the absence of the seventh pair of appendages to an arrest of development. In some respects the new genus resembles Paranthura of Spence Bate. 'The new species is named OC. fontanus. The amphipods found with the isopod are Cragonyx compactus sp. nov., Calliope subterranea sp. noy., and Gam- marus fragilis sp. nov., all without eyes. The new species are all figured and at great length described. Vermes. Synthetic Annelid.t— A. Giard describes Anoplonereis herrmanni, a commensal of Balanoglossus, which appears to belong to the Lycorodide. But there are three tentacles, the proboscis is altogether unarmed, and there are no jaws or paragnathi. The feet are all of the same characters, the notopodium being provided with a single process, and armed with simple capillary hairs. Characters of this * Trans. New Zealand Instit., xiv. ‘ Nature, 1882, pp. 542-3. + Comptes Rendus, xcy. (1882) pp. 389-91. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 779 kind distinguish this new form from any other Lycorid, while the appearance of the parapodia recalls what is seen in the Hesionide and certain Syllide ; in addition to this the presence of the third central antenna is a Syllidean character. On the whole, therefore, Ano- plonereis unites the Lycoridide with the Hesionide and Polynoide on the one hand, and on the other with the Syllidea, which may be con- sidered as being the ancestors of the whole group of Nereids, when that term is taken in a wide sense. Elytra of Aphroditacean Annelids,*—Mr. W. A. Haswell has investigated the structure and functions of the elytra or scales, the possession of which is one of the most characteristic peculiarities of the Aphroditacea. With regard to the functions of the elytra the author distinguishes (1) protection, (2) production of phosphorescent light, (3) sensation, (4) respiration, and (5) incubation. The protective function is in some cases the predominating one. Thus in Jphione the scales are of extreme density, and cover the entire dorsal surface with a complete armour. In others, the scales, though tough, are more readily detached, and in many instances do not com- pletely cover the dorsal surface ; or are so delicate, and so readily parted with when the animal is irritated, that their direct protective action must be very slight. When certain species of Polynoé are irritated in the dark a flash of phosphorescent light runs along the scales, each being illuminated with a vividness which makes it shine out like a shield of light, a dark spot near the centre representing the surface of attachment where the light-producing tissue would appear to be absent. The irritation communicates itself from segment to segment, and if the stimulus be sufficiently powerful, flashes of phosphorescence may run along the whole series of elytra, one or more of which then become detached, the animal meanwhile moving away rapidly and leaving behind it the scale or scales still glowing with phosphorescent light. The species in which the phenomenon of phosphorescence occurs are species characterized by the rapidity of their movements, and also by the readiness with which the scales are parted with; and it seems not at all unlikely that the phosphorescence may have a protective action, the illuminated scales which are thrown off distracting the attention of the assailant in the dark recesses which the Polynoide usually frequent. That the elytra act, like the dorsal cirri, as organs of some special sense, seems probable from their abundant innervation, as well as from the presence, in many instances, of fimbriz and other appendages, some of which act as end-organs for the nerve-branches. In Aphrodita and Hermione the scales have been observed by Williams and Quatrefages to perform an important mechanical function in connection with respiration. In these genera the dorsal surface is covered with a coating of felted hairs, which stretch across * Ann. and Mag. Nat. Hist., x. (1882) pp. 240-2. Proc. Linn. Soc. N.S. Wales, vii. (1882) pp. 250-99 (6 pls.). 780 SUMMARY OF CURRENT RESEARCHES RELATING TO from one side to the other, and enclose a canal open in front and behind, and having for its floor the dorsal wall of the body with the elytra and the “branchial” tubercles. These authors regard the oxygenation of the perivisceral fluid as taking place through the thin integument covering the scale-tubercles and the tubercles at the bases of the dorsal cirri, and have observed the scales to be subject to rhythmical movements, by means of which a current of water is driven continually over the dorsal surface, thus renewing the water in contact with the “branchie.” In species in which the felt-like dorsal covering does not exist, this function would appear to be in abeyance; and in Polynoé and allied genera, so far as Mr. Haswell has observed, the elytra remain perfectly motionless while the animal as a whole is at rest. The sexual products reach the exterior through apertures in the bases of the parapodia ; and the ova are carried by ciliary action to the under surface of the scales, where they remain, adhering by means of a viscid matter, till the embryos are well advanced. Impregnation probably takes place while the eggs are in this situation. Phosphorescent Organs of Tomopteris.*—In two new species of this genus of worms, described, from near the West Coast of Equa- torial Africa, by Dr. R. Greef, under the names T. Rolasi and T. Mariana, the so-called “rosette-shaped organs” are represented not as eyes or glands as has been hitherto done, but as organs for pro- ducing light. In these species they are formed on the middle of the “rudder” of the parapodia as well as on the floats. Under low magnifying powers they are seen to form sac-like spaces, enclosing a globose yellow oily mass which ultimately proves to be made up of a number of yellow tubes aggregated like the seg- ments of an orange, thus producing the well-known rosette-lke appearance. In TJ. Mariana the organs differ according to their position ; those in the floats have the ordinary rosette-characters, but those of the rudders of the two front pairs of parapodia form two large organs occupying almost the entire breadth of the foot, lying near the inner wall of the ventral part; they are rosettes of a deep orange-yellow colour, enclosed in transparent rosette-shaped sacs. The tubes composing the rosette are filled with a granular substance. The organs are supplied with nerves on which ganglia occur over the sacs; from these ganglia proceed fine nerves which penetrate the sacs and reach the rosettes. Each of the segments, 6 to 11 in T. Rolasi and 8 to 11 in Mariana, exhibits a segmental organ near the point of projection of the parapodium from the body; it consists of a short curved ciliated canal with a large internal and somewhat smaller ventral external opening; the former has a frilled margin, the latter has sharp edges. On the ventral side of segments 4 and 5 in sexually mature females occur a pair of transverse genital slits. Priapulus bicaudatus.{—R. Horst distinguishes in the cuticle of this Gephyrean two layers, the outer of which is thin and homo- * Zool. Anzeig., v. (1882) pp. 384-7. + Niederland. Arch. f. Zool., Suppl. Bd., i. (1882) Gephyrea, 13 pp. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 781 geneous, while the thicker inner one is made up of several super- imposed layers; the striking difference between the chemical reactions of the two is pointed out, and the differences in their appearance and structure detailed ; to see them best the cuticle of the proboscis should be examined after maccration. Dermal projections of various kinds are found on different parts of the body; the simplest are the papille which are found irregularly distributed on the rings of the trunk; they are blunt conical projec- tions about 0:1 mm. long, are invested by a thin cuticle, and filled by a process of the hypodermis; the cells of the latter form a continuous layer, with the exception of the central portion where there is a mesh- work of nucleated fibres. The papille on the hinder edge of the last ring are not only distinguished by their greater length, but by the presence within them of a wide-meshed network of extremely fine fibres. Modified dermal papillz are to be found on the cost of the proboscis, where they form conical projections, the two lower thirds of which are invested in a kind of shield. The description of the coste of the proboscis given by Koren and Danielssen is stated to be incorrect, the glands described by them being merely integumentary canals cut across. Beneath the integu- ment, and between it and the musculature there is at the anterior end of the body a space which communicates with the body-cavity by the intervals between the muscular bands. Especial attention may be directed to the fact that for its whole length the nervous system is in connection with the ectoderm ; it is essentially composed of extremely delicate fibrils covered by thicker fibres united into a plexus and passing into the cells of the hypodermis. Some corrections are made in the account given by the original describers of the female genital organs, and the male organs, which were not described by them, are stated to have the same form and position as the female, but instead of a lamellar they have a racemose structure, and the efferent duct is not superficial but principally internal. The nuclei of the cells were of considerable size, and the finely granular contents are divisible into a cortical and a medullary portion. Anatomy of Ankylostoma duodenale.*—W. Schulthess gives a detailed description of this Nematoid, the length of which has been so very variously stated by different authors; the present investigator finds it to vary from 6 to18 mm. After an account of the external form and the differences between the males and females, the writer passes to the integument, the two layers of which are described ; in the study of the muscular layer we may distinguish the longitudinal lines, the muscles, and the papille; in dealing with the last, attention is directed to two hitherto undescribed structures; on the ventral surface of the male the skin, at one point on either side, is traversed by a fine subcuticular tissue, while in the female two similar struc- tures are to be found near the tip of the tail; the significance of these bodies is only incompletely understood. The digestive tract is divisible * Zeitschr. f. wiss. Zool., xxxvii. (1882) pp. 163-220 (2 pls.). Ser, 2.—Vou. II. 3G 782 SUMMARY OF CURRENT RESEARCHES RELATING TO into the oral capsule, a highly complicated organ of fixation, an cesophagus and intestine ; anal glands can only be definitely said to be present in the male. The author concludes with a history of the genital tract, which, well developed in either sex, is remarkably so in the female, where it would appear to be the cause of the greater size of the body. Ina transverse section the genital tube may be cut through at least as many as ten times. Structure of Trematodes.*—On the lungs of two tigers from the zoological gardens of Amsterdam and Hamburg, Dr. C. Kerbert dis- covered what he describes as a new species of Distomum, D. wester- mani. Two individuals were always found enclosed together in one horny capsule. All the organs of this fluke he has noted with care, and he discusses fully their histological characters. Save that he was not able to trace in his specimens the ciliated funnels at the ends of the finest branches of the excretory canals, as observed by Fraipont in D. squamatum and several ectoparasitic trematodes, he gives in the present memoir a complete account of almost every topic con- cerning the anatomy of trematodes in general. Dr. Kerbert resolves the entire body of his Distomum into two strata, cortical and central. The latter is traversed by the dorso- ventral muscles and includes the various internal organs,—nervous, alimentary, excretory, and sexual. The cortical stratum includes—the cuticle proper, the epidermis, the basal membrane (‘‘cuticle” of authors), the tegumentary muscular layer, and the layer of tegumentary glands. Two kinds of cells make up the splint-tissue constituting the bulk of the central stratum. The first are membraneless, of irregularly rounded figure, with finely granular contents and a conspicuous excentrie nucleus or two nuclei. The other cells are branched ; their branches unite to form a spongy network, in the meshes of which the round cells, usually isolated or in pairs, are ineluded. In some places the meshes contain, instead of distinet cells, a protoplasmic residuum with imbedded nuclei. Here and there the trabecule appear under the guise of a very well developed fibrillar connective tissue, with fusiform nuclei among the several fibres. Just under the cortical stratum the cells of this connective tissue blend together into one granular mass of protoplasm, the so-called subcuticular layer. one to the several organs, our space only permits us to notice briefly the sexual. These consist of (a) the genital sinus, (b) the male, and (c) the female organs. T'he genital pore, or common orifice of the whole apparatus, lies in the mid-ventral line, not very far behind the posterior sucker. The sinus itself is lined by a basal membrane, and is an invagination of the cortical stratum stripped of its epidermis. In general form the sinus is conical, with its apex turned backwards and inwards. ‘The apex leads into the female conduit, or so-called uterus. The male opening is situate anteriorly, on the upper wall of the sinus, at its left side. The two, not quite * Arch. f. Mikr. Anat., xix. (1881) pp. 529-78 (2 pls.). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 783 symmetrical, irregularly lobed testes are placed dorsally in the hinder part of the animal. Their vasa deferentia unite in due course to form an ejaculatory duct, whose first portion acts the part of a seminal vesicle. Neither cirrus-pouch nor intromittent organ are present. The female organs are—the ovary and oviduct, the vitellaria, the shell-gland, the canal of Laurer and the “uterus.” The unpaired many-lobed ovary, somewhat dorsal in position, lies to the right of the ventral sucker. The conical continuous oviduct has its narrow end directed towards the shell-gland ; where the oviduct ends the uterus begins. The paired vitellaria are made up of (a) the vitellarian glands, (b) their longitudinal collecting sinuses, (c) the two transverse ducts passing from these, (d) the rather long pear-shaped reservoir into which the transverse ducts debouch and (e) the yolk-duct proper into which it is continued. The shell-gland, a dense cluster of uni- cellular glandules, with interposed connective tissue, invests the innermost section of the uterus, where the yolk-duct and oviduct by their junction give rise to this conduit. Here also Laurer’s canal arises; making two or three convolutions in its course it at length reaches the dorsal surface, where in the middle line its funnel-shaped opening appears, just in front of the transverse vitellarian ducts. A receptaculum seminis is appended to Laurer’s canal not far from its junction with the uterus. The beginning of the uéerus, hidden amidst the substance of the shell-gland and receiving the three ducts already mentioned, constitutes the “ ootyp” of the elder Van Beneden, a term which Dr. Kerbert would extend to the adjoining part of the long winding tube which follows. The coiled vestibular portion of the uterus wholly occupies the space below the transverse vitellarian duct, on one side of the body, between the left diverticulum of the gut and the middle plane. Thus from the genital sinus we pass, by way of the uterus, to all the other female organs, and the whole gyneceum has two openings,—a ventral, leading into the sinus, and a dorsal belonging to Laurer’s canal. The minute structure of the parts which make up this complex of glands and passages is described with very great clearness. The share taken by each in the formation or protection of the ova is also explained. Against the possibility of self-fertilization among trematodes Dr. Kerbert urges many considerations. An internal vas deferens cannot be said to exist. The road by the uterus is not favourable to the transfer of spermatozoa. Most helminthologists, except Sommer, regard Laurer’s canal as a vagina, which it is in the strictest sense,— an organ for copulation but not for parturition, The frequent occur- rence of trematodes in pairs, the conformation of the body by which the back of one individual is closely applicable to the ventral surface of another, the position of the two external sexual orifices (equidistant in Dr. Kerbert’s fluke from the anterior sucker), the presence of spermatozoa in Laurer’s canal and their absence from the genital sinus or uterine coils—these are facts which at present favour the view, that the trematodes, if hermaphrodite morphologically, resemble snails and most monoclinous flowering plants in not being self- fertilizing. 3.42 784 SUMMARY OF CURRENT RESEARCHES RELATING TO Adaptation to Environment in the Trematoda.*—Prof. G. B. Ercolani finds that :— 1. The succession of phases of development is not always the same in all Trematoda; some leave the egg as a ciliated embryo, and require water; others, developed in terrestrial molluscs, have a non-ciliated embryo. 2. Nor are the different phases in development the same for all; the condition of encystation which is necessary for some is omitted in other species, which pass directly from the free cercaria into the free Distomum. There is, moreover, at least one exception to the rule that the larva must at one stage be agamic. 8. The well-known fact that certain nurses are reproduced by asexual generation (either gemmiparous or scissiparous, and the latter either endogenous or exogenous) was observed not only in simple sporocysts, but also in true Rédie. A special form of scissi- parous generation was observed in the racemose sporocysts, where certain living parts are (as in Bryozoa and Hydrozoa) connected by atrophied stolons. 4, The direct conversion of the tail of a cercaria into a nurse was observed several times. 5. Encystation may not only be normal, but also accidental or abnormal; some die when, and at the place where, this accidental encystation takes place; others become, sometimes completely, but more frequently incompletely, adapted to this modification ; in the latter case the generative organs are imperfectly developed, or are not developed at all. Examples of this are to be seen in the adaptation of Cercaria echinula to the intestine of the duck, dog, or rat; this species accommodates itself in different ways, so as to present different zoological characters, though these are not sufficiently distinguished one from another to justify the formation of distinct species. On the other hand, Distomum mentulatum may present quite definite specific differences. The doctrine that each species of molluse has a single determinate species of cercaria, corresponding to a single species of Trematode, is denied, and it is shown that, e.g. Bytinia tentaculata has as many as twelve different species of cercariz. When exogenous gemmation obtains, the buds are produced at the hinder end of the body. While some forms have an excretory apparatus, composed of two vessels con- verging towards a buccal pore, others have no vessels or pores. As to the number of Distomata in one cyst, we had no definite information prior to the observation of Ercolani that from 20-80 larve might be found in large cysts on the peritoneum of tadpoles. Vascular Organs of Trematoda.j—A. Villot points out that in the Trematoda, as in the Cestoda, there are a large number of canals which traverse the whole of the body, and open by a number of pores, either on the surface or into the intestine. Although they con- stitute but a single system, they may be divided into (1) a central * Arch. Ital. Biol., i. (1882) pp. 439-53. {~ Zool. Anzeig., v. (1882) pp. 505-8. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 785 portion, represented by a contractile utriculus, which often extends throughout the whole length of the body, and ends at the caudal foramen; (2) a median portion, consisting of branches of a medium size; and (3) a peripheral portion, formed by a capillary plexus which penetrates all the organs and the parenchyma of the body. In discussing the different morphological interpretations of these parts, the author expresses his opinion that the theory of Prof. Ray Lankester, according to which a portion represents the celom and the rest the nephridium, rests on an arbitrary distinction, inasmuch as there is nothing in the Platyhelminthes which corresponds -to the internal orifices of the segmental organs of Annelids; nor does the author find the explanations of Fraipont either satisfactory or new. Indeed, M. Villot is of opinion that later works have exhibited rather a step backwards; the presence of a cceelom and of true segmental organs in these worms still remains to be demonstrated ; the vascular apparatus consisting of a single system of vessels, which are perfectly continuous and open only to the exterior or into the enteron. Anatomy of Cestodes.*—Dr. Z. von Roboz has examined Soleno- phorus megalocephalus. In dealing with the cuticular structures, he finds that the cells forming the so-called subcuticular layer are connected both with one another and with the cuticle by a fairly well- developed, finely granulated, intercellular substance, in which fine fibrils of connective tissue are to be distinguished. The constituent cells differ in form in different parts, for, while they are elongated in the older joints, and have a finely granular protoplasm with a distinct nucleus and nucleolus, they are spindle-shaped in the scolex and the ‘younger joints, and are connected by processes with the cuticle on the one hand and the interior of the body on the other; the forms of these processes may vary considerably. In regard to the water-vascular system, the most interesting dis- covery of the author would appear to be the demonstration of a special musculature for the longitudinal canals and their branches, an arrange- ment which seems to have escaped the observation of all previous investigators. The following will give some idea of what has been observed as to the nervous system :—Four nerve-cords are, altogether, given off from the ganglioniform enlargements which pass into one another at the region of the two suckers, and so give rise to the formation of a nerve-ring. Finer branches are thence given off, some of which pass into the suckers, while others give rise to the primary cords which pass into the proglottids; the connection between the nerve-branches is such as to give rise to a nerve-plexus embracing the whole of the scolex. It has been found that the oviduct is not merely formed by a thin homogeneous membrane, but that it is invested by an epithelium; from the separate cells special hair-like structures, which call to mind cilia, project into the lumen of the tube; but that they are really cilia was negatived by the length of time that the material for exam- ination had been preserved. The vas deferens appears to be formed * Zeitschr. f. wiss. Zool., xxxvii. (1882) pp. 263-85 (2 pls.). 786 SUMMARY OF CURRENT RESEARCHES RELATING TO of a thin structureless membrane, bounded internally by a single layer of cells; the penis has a very thick cuticle, and in Solenophorus is of some considerable length. Studies on Cestodes.*—R. Moniez here treats chiefly of species of Tenia. In T. pectinata the uterus becomes modified very considerably in the older segments; its ceca become covered with a thick layer of granules which appear to result from luxuriant cellular proliferation of its walls. The granules become detached, and fall into the cavity of the uterus; some of them invest the embryos as a cuticular invest- ment, and the rest form a reticulum which encloses the latter; a similar process takes place in T. cucumerina. The vessels in fF. pectt- nata form numerous large anastomoses between each other. In another species, resembling T. expansa, T. cucumerina, &c., a possibly glandular mass is situated upon the oviduct, with cells each exhibiting an immense vacuole. The uterus forms two tubes extending from side to side of the segment, viz. on the ventral and dorsal surfaces, and lying on the muscular layer. When the uterus is full of ova, wide communications are seen between these main divisions. In T. giardit, the male organs are placed at the two ends of the segment; the spermatozoa of one side cross the segment and issue by the opposite vas deferens, the two currents crossing on the dorsal side. In young segments the vagina is very large, and the ovary appears by contrast to be merely an appendage of it, but later it envelopes and conceals it. The ovum does not exhibit the vitelline masses which appear towards the end of development in T. expansa. Besides the normal muscles are found some large fusiform cells, quite distinct from them, especially abundant in the central zone; in the old segments they are strongly refractive, and devoid of granules; they appear to be homologous with the mother-cells of the calcareous corpuscles. No - yitellogenous glands exist in any of the species referred to. Ligula and Schistocephalus.j—Herr F. Kiessling, working in the laboratory of Professor R. Leuckart, has detailed the structure of Schistocephalus dimorphus and Ligula simplicissima. He maintains the generic distinction of these tape-worms in opposition to Donnadieu, whose description of Ligula (published in Robin’s Journal for 1877) he corrects in several particulars. As containing a revised account of two rather aberrant cestoids, presenting many noteworthy points of agreement, this essay has a value of its own; in so far as it deals with anatomical questions concerning tape-worms generally, it supports the views set forth by Herr Kiessling’s teacher in the current edition of his great work. These cestoids, when mature, inhabit the gut of water-birds. While L. simplicissima, in its asexual phase, infests malacopterous fishes, the larval Schistocephalus is a parasite of the body-cavity of the common stickleback. Both larve agree in being injurious to their hosts, so that external inspection reveals their presence. Curiously enough, Schistocephalus could not be found throughout a wide area * Comptes Rendus, xciy. (1882) pp. 661-3. + Arch. f. Naturgesch., xlviii. (1882) pp. 241-80 (2 pls.). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. . 787 round Leipzig and Halle; near Berlin every second stickleback had its young tape-worm. The complex sexual organs of Schistocephalus are here made intelligible by very clear figures. Why Ligula, as Leuckart has already shown, should differ, bird-wise, in having but one ovary, is not easily explained. In other respects the genitalia of the two worms are very similar. Herr Kiessling insists that there is not a fusion of two ovaries into one, as stated by Riehm to occur occasion-~ ally with Tenia rhopalocephala, New Floscalaria.*—Dr. C. T. Hudson describes a new Floscu- laria (F. regalis), found by Mr. T. Bolton, on Myriophyllum in a pond near Birmingham, which also bore specimens of F'. campanulata, F. ambigua (also one of Mr. Bolton’s discoveries), F. coronetia, and F. ornata. The new rotifer has a nearly circular cup-shaped disk, the edge of which bears six slightly recurved processes ending in knobs covered with long radiating sete. The processes taper from their bases up to the knobs, and are set at regular distances round the cup, giving the rim quite a hexagonal appearance. The two pro- cesses which are nearest to the dorsal surface are shorter than the others, and between them rises a triangular lobe longer than any of the processes, and also crowned with a sete-bearing knob. The disk is thus a kind of cross between that of F’. coronetta and F. ornata, only with this hitherto unique distinction, viz. that there are seven processes issuing from it. All the previously known floscules have either five or three such processes; and there is only one known species that has the latter number, Mr. Hood’s F’ trifolium. Ehren- berg’s six-lobed F. proboscidea is no doubt the five-lobed F. cam- panulata. F. regalis is not one of the larger species. The majority of those hitherto seen were about ;1; of an inch, and the largest was =). The smaller, and probably younger, ones were unusually transparent for floscules. The two eyes were readily found on the dorsal side, both by direct and by dark ground illumination. Dr. Hudson was surprised, also, to find how easy it was to see the semicircle of small cilia which lies at the bottom of the cup on the ventral side. In the majority of the other species these are extremely difficult to make out. On the other hand, the tube of the new floscule was in every instance almost invisible. Its existence could just be made out, but that was all. No great stress ought, however, to be laid on this, as the tubes of all species vary very much according to their habitat. When fully expanded it usually extends outwards all the six linear processes, but curves inward the seventh triangular one over the cup-shaped disk, and uses both it and its sete to prevent the escape of its prey. Desiccation of Rotifers——The Rev. Lord 8. G. Osborne referring to a previous letter of Mr. Jabez Hogg as to the Rotifers and Amabe * Midl. Natural., v. (1882) p. 252. 788 SUMMARY OF CURRENT RESEARCHES RELATING TO revived from “earth” taken from Durwaston, says* that it was simply the dust of the garden which happened to deposit itself in certain cup-like receptacles made artificially of a substance which coated itself with an oxide, giving to the dust when wet a rusty appearance. After having been in a drawer for more than three years no symptom could be detected of a decrease in the number or activity of the stock. He adds, “It is to me inexplicable that although I have collected very many specimens of the rotifer (RB. vulgaris) from plants taken from ponds, I never could acclimatize these in my tanks, so that they would bear the drying process so successfully as when procured after my own fashion.” Echinodermata. Heteractinism in Echinodermata.t—In dealing with a small col- lection from Point de Galle, Professor F. Jeffrey Bell describes a specimen of Ophiomaslix annulosa in which one arm measures as much as 300 mm. in length, and gives an account of another example, which, as he calculates, may have had a total spread of 800 mm., or nearly 32 inches. He points out that such a form must be continually sub- jected to the loss of part of an arm, but that owing to vegetative repetition the loss will hardly perhaps affect the individual, and not at all the species. Contrary to the opinion of such observers as Haeckel and Simroth, he holds that such external irritation is not to be neglected in discussing the question of heteractinism. There would appear. to be in all echinoderms a capacity for self-injury, which, in these days, is excited by pain, fear, or anger; while the starfish may only throw off an arm, an ophiurid, in consequence of its greater centralization, undergoes fission of the disk. The disk thus injured may give birth to more arms than it has lost; and when this habit becomes inherited, we may get six-rayed forms; such are to be found in Ophiacantha, where, in some cases, there is so well-marked a cenogeny that, not only are the adults sex-radiate, but the young are developed vivipar- ously, and never exhibit any bilateral symmetry. The origin of this tendency to self-mutilation is ancient and deep- seated, for some polyactinic forms (Brisinga) lose their arms for the purpose of setting free their genital products; the tendency would seem to be lost in those which, by the power of the spines, are able to resist all foes, or those which by their capacity for vegetative repetition are enabled to atone for it. When the tendency is seen in others it has quite a different physiological significance, for the result is true asexual reproduction. Considerably modifying a table once given by Haeckel, Professor Bell points out that in the Echinodermata we may haye— i A. Sexual reproduction. a. With metamorphosis (“metagenesis and internal gem- mation ”’). 8. Without metamorphosis (viviparous Echinodermata). * Times, 4th October, 1882. + Ann. and Mag. Nat. Hist., x. (1882) pp. 218-25. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 789 B. Asexual reproduction. a. Fission, with repair. 8. External gemmation from a single arm. In certain cases heteractinism would appear to be due to increased activity, consequent on inflammation. Circulatory Apparatus of Regular Echinoids.*—R. Koehler de- scribes the presence of two circular circumcesophageal vessels, and of two vessels in each ambulacral zone; he also proves the complete independence of the nervous and circulatory systems, and finds that this last communicates with the excretory organ by means of the sand- canal. The sand-canal is not simple, but is really formed of two, which are closely connected together; the only one which has as yet been described is independent of the ovoid gland of Perrier, or the organ of excretion, while the other is connected with it. Transverse sections of the sand-canal reveal the presence of one tube regularly lined by epithelium, and of another whose lumen is partly filled by bars of connective tissue which form a delicate reticulum supporting protoplasmic cells. The second canal, when it reaches the ovoid gland, increases in diameter, the partitions in its lumen become more numerous, while the gland itself consists, as in irregular Echinoids, of trabeculz of connective tissue which are very delicate, and have their alveoli filled with protoplasm and pigmented bodies. The two circumeesophageal vessels communicate with one another at the level of the Polian vesicles. Structure and Development of Ophiuroids.t| — K. Nicolas Christo-A postolides has at length published, in the French language, the full text of his memoir on Ophiuroids, with six plates. While availing himself of modern aids to histological research, he enjoyed the advantage of a copious supply of living specimens, and he rests his claims on the circumstance that he made good use of these as well as of preparations. Five genera, including eight species, were examined. Not much is said of the skeleton and body-wall in the adultanimal. The soft parts are minutely analyzed.{ The simple sac-like alimentary canal, without mesenteries or free glandular appendages, consists of four separate layers—(a) an internal ciliated epithelium, (b) a brown layer with long (muscular) fibres, (c) a cellular (secretory) layer and (d) an investment of connective tissue. In this last are found peculiar triradiate calcareous spicules, the free ends of whose rays become again triradiate. There is a distinct, though short, cesophagus. The larval form has an anus, wanting in the adult. Imprisoned brittle-stars, eight or ten days after being captured, show an opening in the middle of the back. Our author believes that, in consequence of starvation, a sinking of the dorsal wall takes place; this, with the central portion of the gut, becoming engaged among the five oral pieces, is bitten off as a substitute for food. * Comptes Rendus, ‘xcv. (1882) pp. 459-61. + Arch. de Zool. Exper. et Gén., x. (1882) pp. 121-224. + See this Journal, i. (1881) pp. 466 and 606; ante, p. 199. 790 SUMMARY OF CURRENT RESEARCHES RELATING TO The existence of a circulatory system is denied, apart from the water-vessels and the general lacune of the body; albeit that these lacunz are so disposed between the various internal organs, or these and the integument, as to present a certain definiteness in their arrangement. The true madreporic tube is figured with the pyriform gland (hitherto mistaken for a heart) placed beside it, the two being enclosed in a common investment strengthened with calcareous pieces and constituting the sand-canal of authors. The circular water- vessel of the larval brittle-star is closed from the first. Our author does not fully explain how it comes to surround the gullet. He simply says that the aquiferous system encroaches upon the digestive tube. Probably it slips over the rudimentary gut soon after the dis- appearance of the anus. The tubular ring, at an early period, sends forth five rays, each of which again gives off five ceca. Of these ceca the central one becomes the longitudinal ambulacral vessel of the arm; the adjoining ceca supply the first pair of tentacles; the two outer ceca represent the superior pair of buccal tentacles, whose common trunk elongates and produces the second pair. At first all five ceca have their points outwards; at a later stage the buccal pair turn in to face the mouth. The young Polian vesicle at first, also, grows from the circumference of the ring towards its centre ; subse- quently this direction is reversed. Not all brittle-stars have Polian vesicles. They are absent in Ophiothria versicolor, which is thus distinguished from the common O. rosula, as likewise by its less convex arms and more variable tints. While in certain Ophiuroids, e. g. Ophioglypha, the genital organs are appended to the respiratory pouches, as Ludwig has described them, they are in others more or less distinct. They are so far independent in Ophiocoma nigra that, when this species is dissected with its dorsal aspect upwards (in its natural position) the respiratory sacs must be removed before the genitalia can. show themselves. In Ophiothrix each cluster of genital “ glands” is replaced by a single organ. The development of the Ophiuroids is described in the case of two species, Ophiothrix versicolor and Amphiura squamata. 'The first represents that section of the group in which there is an early oviposition and metamorphosis of the young; while Amphiura, further exceptional in being hermaphrodite, is viviparous. Nevertheless the organogeny of these two brittle-stars presents many more points of agreement than of difference. The resemblance of the free larva to the pluteus of the Hchini, on which so much stress has been laid, is to be regarded as more superficial than real, and comparatively simple larval forms may occur beside those whose very striking transitory appendages render them rather abnormal than otherwise. ‘The researches of Metschnikoff, the only observer since Miller who has contributed much to our knowledge of this subject, should be com- pared with those of our author. In many features the development of the Ophiuroids essentially approximates to that of the true star- fishes, as first described with adequate fullness in the beautiful memoir for which we are indebted to the younger Agassiz. On three important topics, demanding renewed inquiry, the — a ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 791 author differs from most embryologists. He supports (against Ludwig) the view, formerly urged by Lyman, that the oral skeleton is not made up of modified proximal elements of the arms, since it has an earlier and independent origin. The alimentary canal he describes as formed by delamination, not by invagination as in other echino- derms. Lastly, he contends that the two (rarely three) rudiments, from one of which the future water-system is derived, do not arise as diverticula of the digestive tube, but from cells which lie between it and the ectoderm of the embryo. Formule for Comatulide.* — Professor F. Jeffrey Bell in an “Attempt to apply a method of formulation to the species of the Comatulide,” deals with the two large genera Antedon and Actino- metra; these two forms he proposes to distinguish by the signs A and A’; while for the brachials, distichals, and palmars he uses the letters B, D, and P, whenever their respective axillary forms a “syzygy ” ; according as the first, second, or third brachial is a syzygy he adds the number 1, 2, or 3. Dealing with the cirri and their joints he divides both into three sets of few, moderate, or many ; these are dis- tinguished by the letters a, b, and c, the cirrus-mark being placed above and the joint-mark below the fraction sign. A ten-rayed Antedon with 15 cirri of 40-50 joints, with the first syzygy on the third brachial, has its formula written 3 A- ; a multiradiate Actino- metra with its radial and palmar (though not its distichal) axillaries syzygies, with a syzygy on its first brachial, with less than 13 cirri and more than 40 cirrus-joints, has the formula 1 A’ R P =. When a character is not constant it is placed in brackets, and when a multi- radiate species has not any axillary in R, D, and P, its formula is placed under the mathematical sign of the square root. Holothuroidea of the Norwegian North Sea Expedition.;—In another magnificent contribution to the fauna of the Arctic Seas, D. C. Danielssen and J. Koren describe in detail the new forms of which they have already published diagnoses. Of the seventeen genera in the collection five were new, and of the twenty-five species, six were new. Kolga hyalina is remarkable for the absence of fibrillar tissue from the subepithelial connective tissue, an arrangement known in no other Holothurian ; the calcareous ring is very imperfectly developed, and the sand-canal presents an embryonic condition in still remaining open; the bilateral symmetry of this form does not, in the - opinion of the authors, weigh sufficiently against the totality of their organization, to justify us in placing it high in the scale. In Tro- chostoma thomsonii well-defined vascular plexuses were seen in the wall of the rectum, but they do not seem, as in some insects, to have a respiratory function, but to serve as a system of lymphatic vessels. Two respiratory tubes are connected with the intestine, but there is no proper cloaca ; the madreporite is remarkable for its position, being * Proc. Zool. Soc. Lond, 1882, pp. 531-6 (1 pl.). + Norske Nordhays Exp. 1876-8, vi., Zoology, 4to, 90 pp. (13 pls. and 1 map). 792, SUMMARY OF CURRENT RESEARCHES RELATING TO placed on the canal, but not at its extremity. Ankyroderma appears to be transitional between the Synaptide and the Molpadide. Histology of Digestive Canal of Holothuria.*—H. Jourdan finds, in Holothuria tubulosa, that the cells of the epithelial or peritoneal layer are of two kinds; simple endothelial cells arranged in a single layer, cylindrical in form and often ciliated, while the others are of the type of mucous cells. The muscular layer is formed by circular and by longitudinal fibres, the former being continuous and regular, while the latter are most numerous in the anterior region of the tract, while, again, they are placed internally to the circular muscles anteriorly, and are external to them posteriorly. A number of lacune are to be found in the connective layer. The cells of the in- ternal epithelial layer differ remarkably in different regions; while they are at first excessively long, and have the form of delicate fibrils, they are, further from the mouth, distinctly cylindrical. The glan- dular cells with granular contents are ovoid or spherical and appear to be confined to the more anterior regions, while the so-called mucous glandular cells are more widely distributed, with, however, consider- able variations in their form, size, and number ; in the more posterior portions of the intestine they may be compared to the mucous cells of the Vertebrata. Ceelenterata. Studies on Celenterates.j—Dr. O. Hamann finds that the cnido- cells are interstitial cells which have developed an urticating capsule in their interior and have then passed from the lower to the more super- ficial layer of the ectoderm ; it may be shown by the presence of the nucleus after the formation of the capsule that this last owes its origin to the protoplasm of the cell. At the same time the cell is capable of producing a process which becomes connected with the supporting lamella, and has many if not all of its characters; this process is not a mode of communication from the exterior to the interior of the organism, but only a supporting fibre; if this view be the correct one it is clear that the cnido-cells cannot be looked upon as having a sensory function, but rather as being partly defensive and partly offensive. In discussing the pseudopodioid cells of Hydra it is remarked that, if we examine the region of attachment we find that the ecto- dermal cells are here different from what they are in other parts of the body; cylindrical in form, their contents are not clear but finely granular ; if separated, after maceration, they are seen to have only one and not two of the so-called muscular fibrils; and if carefully studied in the living specimen they may be seen to be capable of excreting mucus; if examined, when the animal is in movement they may be shown to protrude pseudopodia. No interstitial cells or enido- cells are to be found in this region. The apparent absence of pseudo- podioid cells in all other Ccelenterates leads the author to believe that Hydra is really a form standing very close to the ancestor of the Hydroid Polyps; though he recognizes the possibility of the objection being raised that Hydra has lost its skeleton in fresh water. * Comptes Rendus, xcy. (1882) pp. 565-6. { Jenaisch. Zeitschr. f. Naturwiss., xv. (1882) pp. 545-57 (2 pls.). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 793 Organization of Hydroid Polyps.*—Dr. O. Hamann finds that in Hydroid Polyps there is rarely more than one—the longitudinal—axis ; sometimes, however, the tentacles may be seen to be arranged along definite rays, so that the symmetrical arrangement of organs is not confined to the Meduse ; he shows that other genera besides Tubularia are provided with teniole, and he uses the presence or absence of this character as an important aid to classification. In the Teniolatz he finds an endodermal musculature not only in the hypostome, to which it is confined in the Intzniolatz, but also in the stomach. True sensory cells or nerves were never detected in the ectoderm, and the structures which seemed to be such were found on closer examination to be merely interstitial cells. The endoderm of Aglao- phenia was found to be filled with yellow cells, which appeared to be unicellular alge taken in for the purposes of nutrition. The cells of the ectoderm were found to be (1) epithelio-muscular cells, (2) proper epithelial cells, (3) interstitial, deeper-lying cells, (4) true muscle cells, (5) interstitial cells converted into enido-cells, and (6) glandular cells; after describing these the author passes to the supporting lamella, which is nothing more than a structureless thin sheet, which is secreted from the endoderm. In dealing with the origin of the Meduse, Dr. Hamann starts from a polyp-stock, any cells of which might become an egg-cell or a sperm- cell; imagining that separate persons might become broken off or separated from the colony, we can suppose that if they become adapted to the new conditions they would continue to reproduce their kind, but they would at the same time be modified by their new life, become, in fact, Meduse ; it will be seen that the complete homology of the Polyp and Medusa is here recognized. The planula is stated to be always formed by delamination or by the wandering of ectodermal cells. ; The relations of various Ceelenterata are exhibited in the following table :— Siphonophora Koralla Scyphostoma . N Spongicolide TmRNIOLATE INTHNIOLATE HyprRocorALLINEX | Hydra (1) Sertularinz (2) Campanularine | (Hydrusz) Archydra., * Jenaisch, Zeitschr. f. Naturwiss., xv. (1882) pp. 473-544 (6 pls.). 794 SUMMARY OF CURRENT RESEARCHES RELATING TO Tn the classification of the Hydroid Polyps the absence or presence of the teniole gives us I. Inteniolate with the families Hydrina, Campanularine, and Sertularine, and Il. Teeniolate, divisible into the Acolloblaste (with fourteen families), where the supporting lamella takes no part in the formation of the teniole, and the Colloblaste (with the families Spongicolide and Scyphostomide) where the support- ing lamella enters into the teniole. A study of the histiogenesis of the Hydroid Polyps shows that any histological element, whether of the ectoderm or of the endoderm, is capable of becoming converted into a generative, muscular, glandular, or other cell; the part of the endoderm which lines the hypo- stome is regarded as having a secretory function, while that found in the gastric cavity is thought to be digestive. It is important to note that the author has convinced himself that ovarian or sperm-cells are sometimes derived from the ectoderm and sometimes from the endoderm, in face of the definite statements made by some authorities. Hydra,*—C. F. Jickeli, having been attracted by the view of Brandt that Hydra grisea is but a young stage of H. viridis in which the symbiotic Zoochlorella has not yet appeared, has addressed himself to the study of the differences between these species. He finds characteristic marks in the form of the urticating capsules, sufficiently striking to enable one to distinguish, from a small piece of well-preserved ectoderm, from which form the piece was taken. Further than this, H. grisea has in its endodermal cells bodies of a yellowish colour, which take the place of the green bodies of H. viridis, and, as these do not seem to have been detected by Brandt, the author believes that that naturalist had under observation not H. grisea but H. vulgaris (fusca), and this view is confirmed by the fact that while H. vulgaris may, in some stations, be quite common in spring, it is very rare in summer when H. viridis is abundant. Vital Phenomena of Actinie.t—B. Solger finds that the Actiniz have no free enzymotic digestive secretion; treatment of the mesen- terial filaments with water dissolves out a tryptic enzyma in Sagartia and Anthea and a peptic one in Cerianthus; the yellow bodies (or zooxanthellae of Brandt) which are found in the cells of the endoderm are probably, the author thinks, foreign alge. Neither the cells of the mesoderm nor of the ectoderm are capable of digesting albuminoid bodies; when a so-called anal pore is present (as in Cerianthus) it does not serve for the evacuation of the fecal masses, but for that of the generative products and the expulsion of water. As to their respiratory phenomena, we find that Actiniz reduce oxyhemoglobin, but, on the other hand, there are great differ- ences exhibited by them in their power of resisting oxygen-starvation, Sagartia troglodytes living for a long time, S. parasitica dying soon. Some concluding observations are made on the results of recent researches into the chemical constitution of these ccelenterates. * Zool. Anzeig., v. (1882) pp. 491-3. + Biol. Centralbl., ii. (1882) pp. 399-404. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 795 Ovaries of Actinie.*—R. Hertwig finds in Corallimorphus rigidus that the smallest ova form groups of 2-4 cells between the bases of the epithelial cells, and that the larger reach almost to the surface of the epithelium; an egg-cell taken in the act of passing outwards was seen to have part lying in the mesoderm and part in the endoderm ; the two halves were separated by a constriction which was sufficiently deep to affect the form of the nucleus. Young egg-cells are con- nected with the epithelium by a short cord; when they leave this region their basal ends first pass into the mesoderm, and soon after the nucleus follows that portion. The filamentar apparatus of the egg-cell, which was only a temporary condition in this form, was more lasting in Halcampa clavus, a conical protoplasmic cord passing from the egg through the supporting lamella tothe epithelium. Attention is directed to the peculiar form of the epithelial layer investing the egg, and to the curious fact that a similar phenomenon is to be ob- served in the Acraspedota, where the ova are likewise of endodermal origin. Skeleton of Madrepores.t—The law of multiplication of the septa in hexaradiate corals, as first stated by Milne-Edwards and Haime, has gained a general if somewhat qualified acceptance. Schneider and Rétteken have proposed to modify it as regards the later and more puzzling stages of development. Semper seems to doubt the possibility of establishing the truth of any such formule, in the presence of the many and intricate variations which even the individuals of one species of coral may display. In his beautifully illustrated memoir on Astroides, Lacaze-Duthiers scarcely enters on the discussion of this question. We cannot cite any other zoologists who have made serious contributions to the subject. G. v. Koch, however, who for years has studied the development and structure of the skeleton of the Anthozoa, now comes forward to introduce order where before there was chaos. Neither the law of Milne-Edwards nor that of Schneider are, in his opinion, supported by facts. Semper’s scepticism has a certain justification, but must also be rejected. It may be accounted for as follows :—in one or more primary sectors the formation of new septa is liable to sustain a check ; thus septa of the second cycle belonging to such a sector may resemble those of the third cycle elsewhere in the same coral, and so with other cycles. Or, otherwise expressed, a hurried or retarded development of certain septa may here and there occur. Our author’s hypothesis, wherein he sums up the general result of his own investigations, is certainly very simple and intelligible :—Throughout the Hexacorallia, both Imporosa and Perforata, an approximately con- temporaneous formation of septa takes place within all the chambers of the calyx, so that the septa of each added cycle are equal in number to all the previous septa. Exceptions must be referred to direct modification or to inherited changes in the growth of the whole animal. * SB. Jenaisch. Gesell. Med. u. Naturwiss., 1881, pp., 18-20. + Gegenbaur’s Morph. Jahrbuch, viii. (1882) pp. 85-96 (1 pl.). 796 SUMMARY OF CURRENT RESEARCHES RELATING TO The attempts hitherto made to formulate the succession of the septa in the six-parted corals are at once shown in the annexed dia- gram, which we offer for the sake of comparison. SCHNEIDER. | MiLNe-EDWARDS. Kocu. bo ma Pe Ooh ow Pe | ie OC Sl Cr SSC | | | | | Herr Koch has proceeded by examining, in their proper order, successive slices of single specimens, carefully selected, cleaned, and filled with black sealing-wax. A number of corals belonging to the same species were thus analyzed, one by one, and afterwards compared with each other. Caryophyllia cyathus was chosen as representing the Imporosa, Dendrophyllia ramea the Perforata. The simultaneous appearance of the first six septa contrasts with the very peculiar succession of the primary mesenteries. Herr Koch regards this succession as due to modification. In the second section of his present essay Herr Koch maintains that the theca of each corallite among the Anthozoa is formed by secondary coalescence from its septa, and not independently within the body-wall. Four Mediterranean corals, including the two species noted above, appeared to show that the theca really arises in this manner. Studies on Gorgoniade.*—G. v. Koch associates under the name of Alcyonaria axifera those eight-rayed corals which possess an internal axis but which do not have it, like Corallium, formed of fused spicules, but developed from an axial epithelium; such forms are Gorgonia, Gorgonella, Muricea, Pruinoa, &c. After describing some new or old species the author passes to an account of the development of G. verrucosa; the rounded or oval egg is sur- rounded by a hyaline envelope and has a stalk-like process of attach- ment; both these are invested by a cylindrical epithelium derived from the endoderm. The testes are distinguished from the ovaries by their generally paler coloration; the young spermatozoa are at first rounded, but later on get long delicate tails; fertilization is always effected within the mother-polyp, and, it is possible, before the egg breaks away from its stalk. In the later stages of segmentation the outer cell-layer becomes converted into a layer of cylindrical epithelium (ectoderm); the nuclei of these are smaller than those of the cells within, and the author has been able to confirm his earlier statement that the spicules are developed in the cells of the ectoderm. * MT. Zool. Stat. Neapel, iii. (1882) pp. 537-51. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 797 Development of Aleyonaria.*—A. Kowalevsky and A. F. Marion have studied the development of two species of Clavularia and of Sympodium coralloides; they find that, as regards the segmentation of the ovum, which has never yet been completely observed in an Alcyonarian, the fecundated ovum of C. crassa remains for some time without dividing, and the ordinary histological reagents fail to demon- strate the presence of any nucleus, though, after segmentation, the nuclei are, notwithstanding their small size, easily recognizable. There would appear to be so rapid a division that no two-sphere stage is to be made out, six segments being the smallest number that can first be recognized. A peripheral and a central mass are easily separable from one another, and the former soon gives rise to a well-marked ecto- dermic layer; the endoderm is not slow in its appearance, and the store of yolk becomes rapidly used up. The larva having become fixed, its narrower end is depressed, and gives rise by invagination to an cesophageal sac, the bottom of which becomes pierced and forms a means of communication between the mesenteric cavity and the exterior. Meanwhile the ectoderm has become thickened by the formation of a layer of connective tissue, which may be regarded as the pseudo- mesoderm. Cells migrating from without give rise, in Sympodiwm, to small calcareous nuclei which become the sclerites ; but in Clavularia the formation of the rudiments of these hard parts is delayed for some time. Attention is also directed to the variations in the mode of develop- ment which are exhibited by Sympodium. While some larve undergo their changes rapidly, others retain their vermiform characters for a longer time, and in these there is no formation of sclerites, but the ecto- derm is differentiated in the manner of Clavularia ; at the base of the pseudo-mesoderm there is formed a fibrous layer which corresponds to an annular muscular band. A large number of primitive mesenteric septa are developed, and the whole of the endoderm is supplied with a layer of longitudinal muscular fibres; a transverse section of these larve is almost exactly comparable to that of an Actinian. Porifera. Manual of the Sponges.—The first volume of Bronn’s ‘ Thier- reich, on the Amorphozoa, written by Bronn himself, was published in 1859. Itincluded the Protozoa and the Sponges. Biitschli having undertaken the second edition of the Protozoa, of which the thirteenth Lieferung has appeared, a revised account of the Sponges is no less imperatively called for. Upon Dr. Vosmaert has devolved this task. The first Lieferung of his ‘ Porifera’ is now before us; its contents are bibliographical and historical, with four plates. A good epitome of the researches of Oscar Schmidt, Eilhard Schulze, and others, is certainly much needed by students, no complete general work on the Sponges having hitherto been issued. * Comptes Rendus, xev. (1882) pp. 562-5. + ‘Dr. H. G. Bronn’s Klassen und Ordnungen des Thier-reichs. II. Band, Porifera. Neu bearbeitet von Dr. G. ©. J. Vosmaer.’ Winter, Leipzig und Heidelberg, 1882. Ser. 2.—Vot. II. 3 Ff 798 SUMMARY OF CURRENT RESEARCHES RELATING TO Development of Reniera filigrana.*—W. Marshall is led by his studies on this sponge to the conclusion that the Spongie represent a very old branch of the Ccelenterate stem, in which, in consequence of later adaptations and compressions, we have but a scanty phylo- genetic history. Attention is directed to the view of Leuckart that the Porifera have a relation to the Coelenterata in consequence of the homology of the ciliated cavity of the simple calcareous sponge (Grantia), with the body-cavity of a hydroid polyp, the mouth-orifices also correspond, and the pores of sponges are comparable to the water-spaces of the Coelenterata. On the other hand, Balfour has insisted on the striking peculiarities of the sponge-larve, the early development of the mesoblast, and the remarkable characters of the digestive canals, as evidence in favour of the independent origin of the Poriferous phylum. To this Marshall answers that the larval peculiarities are chiefly to be seen in the Calcispongiz, while the Fibrospongiz have much more similarity to certain higher Ccelenterates (e.g. Hucope). The sessile condition of the sponges may be supposed to have conditioned the development of a skeleton, and this may be taken to be one of the causes of the marked development of the mesoderm. ‘The entrance of the water-pores into the service of the digestive organs is looked upon as due to a change in function, which has again necessitated a greater development of the mesodermal tissues. It is next pointed out that in both groups we see a centri- fugal canal system differentiated from the gastric cavity, which often breaks through the ectoderm and communicates with the exterior by permanent or inconstant pores; where there are tentacles present the canals or a part of them may be developed therein, and in some cases the pores opening from them to the exterior become so well developed that an astomatous condition is set up. In addition to this, the © author believes that the ciliated investment of the tubes is derived from the endoderm layer. As tothe absence of tentacles and stinging cells, attention is directed to the absence of both these organs from Beroé, and to the probability of their being nothing but the results of adaptation in the true Coelenterata; while, further, their absence in sponges is to be explained by the present mode of nutrition exhibited by these forms. Sponges and Ceelenterates are, then, Metazoa with gastric cavities and mesenterial pouches, with centrifugal canals arising from the former which may open to the exterior by pores and take in nutriment ; they are invested by endodermal cells, which may become converted into flagellate cells. They are both developed from a common Prot- actinian stem-form. New Fresh-water Sponges.—Mr. H. J. Carter describes + a new species of Spongilla from Bombay (S. bombayensis) of which only the statoblasts have been found. The most characteristic part of this species is, that the chitinous coat is spiculiferous, and that when the statoblast is divided through the middle or the outer layer crushed, * Zeitschr. f. wiss. Zool., xxxvii. (1882) pp. 221-46 (2 pls.). t+ Ann. and Mag, Nat. Hist., x. (1882) pp. 362-72 (1 pl.). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 799 it also comes out divided or entire, as the case may be, when it may be mounted in Canada balsam. It then presents a damascened appearance, and becomes a very beautiful microscopical object, owing to the layer of spicules lying more or less parallel to each other, although in different directions, being immersed in the transparent light amber- coloured chitinous substance of which the coat is otherwise composed. The way in which the statoblast is firmly fixed to the stem of the herbaceous plant on which it was found, is also peculiar, inasmuch as the thick spiculiferous or external coat is continued on to the wood, thus forming a kind of neck or expanded base, which is so strongly attached as to bring away a portion of the wood when removed; while the “aperture,” single or in plurality, varies in position on the free surface. They are for the most part more or less emptied of their germinal contents, and surrounded by a little sponge-structure, in which the skeleton spicules are found, one of which being microspined, at once distinguishes them from those of S. alba and S. Carteri, by whose statoblasts respectively and only they are frequently accompanied. Mr. W. A. Haswell also describes * two new species of Spongilla (S. sceptroides and S. botryoides) from Brisbane, and Meyenia Ramsayi from New South Wales. Only one species of Australian fresh-water sponge has hitherto been described, being the one from Victoria, named by Bowerbank, S. Capewelli. Another species of Meyenia cannot yet be sufficiently determined from the few spicules found. Protozoa. Butschli’s. Protozoa.—Nos. 10-13 of this part of Bronn’s ‘ Thier- reich’ have appeared, with plates XVII—XL. The classification of the Heliozoa is completed, and the Radiolaria also, which have nearly 150 pages devoted to them; it is pointed out, in dealing with the “parasites” of the Radiolaria, that their nutrition and metabolism are really essentially aided by the presence of those guests which are of vegetable origin. An account is given of the deformed creature which Haeckel called Thalassicola sanguinolenta, and which has been modified by the taking of foreign bodies into its extra-capsular sarcode. It would seem to be certain that some of the group are phosphorescent, but the author is not so confident that a number of the forms said to dwell at the bottom of deep oceans really do so, as nothing in the structure of many of them seems to afford any support to the doctrine. Following Hertwig the group is divided into the Peripylea and Monopylea, according to the characters of the central capsule; while the third division is that of the Pheodaria or Tripylea, of which little is as yet known. The concluding pages begin an account of the Sporozoa, and there the Gregarinidz are chiefly dealt with. New Ciliate Infusorian.j—Mr. F. W. Phillips describes a new genus and species under the name of Calyptotricha pleuronemoides, found attached to Myriophyllum. ‘The animals are furnished with a * Proc. Linn. Soc. N.S. Wales, vii. (1882) pp. 208-10. + Journ, Linn. Soe. (Zool.) xvi. (1882) pp. 476-8 (1 fig.). oH 2 800 SUMMARY OF CURRENT RESEARCHES RELATING TO remarkable transparent hyaline ovate lorica, opening teat-like at both ends, and a vibratory membranous hood or velum almost equal to the ventral length. The anterior extremity of the body is protrusible from the lorica. ‘Their length is -001 inch, and the non-vibratile setose body-cilia are about two-thirds of this length, with shorter stronger vibratile cilia at the entrance of the velum. Actinophrys sol.*—Dr. A. Gruber, dealing with the fusion of two or more individuals in the Heliozoa, says, that unfortunately the signification of this process is still obscure, and we are not in a position to establish an analogy with the accurately investigated conjugation in the Infusoria, since no alteration in the nuclei of the united individuals has ever been observed, nor any fusion of the nuclei. The difficulties of observation are enhanced by the fact that it is often impossible to see the nucleus in the living animal. As Dr. Gruber had recently a somewhat rich collection of Actino- phrys sol at his disposal, he tried, with the aid of Korschelt’s staiming process,f to arrive at some conclusion upon these points. He has not, however, yet succeeded so well as might be desired, and must, he says, defer any decision until further observations have been made. He has, however, become acquainted with some other peculiar facts which are of interest, and which he thinks it advisable in the first place to make known. Two specimens of Actinophrys sol were observed, one well-formed, and another only about a third or fourth of its size; scarcely had the pseudopodia of the two touched than the smaller individual was quickly drawn to the larger, and united withit. After the union was complete, he fixed the animal and coloured it, when to his surprise only one nucleus was present. The experiment was repeated several times. The first conclusion was that a union had taken place not only of the protoplasm, but also of the nuclei, but on fixing and colouring the objects before their union was completed, it was found that the small individuals did not contain any trace of a nucleus. Subsequent examination showed a large number of the small forms to be without any nucleus. The rapidity with which the blending process takes place on the meeting of two individuals is remarkable: in from ten to fifteen minutes at the most, the small Heliozoa are absorbed by the large ones. It is the same when the Actinophrys does not take its fellow, but another organism, with this difference, however, that in that case the prey dies by contact with its enemy’s pseudopodia, while the smaller individuals of the same species do not cease to show all the ordinary signs of life, indeed even an increased motion of the pseudopodia, and regular pulsation of the vacuoles. Once the author succeeded in bringing one after another three small ones to a larger one, and they were all fused in a very short time. During this process two flagellates were caught and devoured. Strangely * Zool. Anzeig., v. (1882) pp. 423-6. + Cf. this Journal, ante, p. 574. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 801 enough a fourth, and to all appearance similar small individual, was, as often as it was brought near to the larger, rejected, even though entangled in the pseudopodia in a manner which, in previous instances, had “ produced an attraction like that of magnetism.” In all the above cases this blending of a nucleated individual with one or more small non-nucleated ones can have no other significance than that ofa simple increase of the substance of the large Actinophrys, which in the last instance, after the absorption of three individuals, had reached its highest point, so that the animal resisted any further accretion. On the question of conjugation, and the phenomena of repro- duction connected with it, these observations throw no light; but the fact is demonstrated, that the Protista, which as perfect cells possess a nucleus, are yet able to live without. It may be objected that the small individuals may originate through some pathological process, and not through the normal fission of the larger Actinophrys. This can hardly be the sole explanation, for, first, Dr. Gruber has himself observed such fission in the Actinophrys, and it occurs still more frequently in the Infusoria, where one animal divides into several dissimilar fragments; while, secondly, he has found it to be the same with the non-nucleated as well as with the small nucleated examples. All this, however, does not prevent our seeing in the non-nucleated Actinophrys their general vital phenomena similar to that of a perfect individual, for they show the most active protoplasmic movements in their changing pseudopodia, and possess an excretion vacuole which pulsates as in the normal animal, and they are also in a position to take nourishment, and to digest it in another vacuole. A difference between the nucleated and non-nucleated animals may lie in the fact that in the act of blending, the réle of the smaller creature is simply passive, so that the conscious action (if the ex- pression may be allowed) is only on the part of the normal individual. But even this failed in the following observation: An individual equal in size to a full-grown Actinophrys, which, however, raised the suspicion that it had no nucleus, was placed close to a small one, whereupon the same process of union occurred as before. The larger one, however, had no trace of a nucleus any more than the smaller, although it had behaved as a nucleated animal. This case shows also that the non-nucleated Actinophrys is capable of growing. The author, therefore, draws the following conclusions from his observations:—The nucleus has no relation whatever to the part which movement, nutrition, excretion, and growth play in the sur- rounding protoplasm, nor to any of the physiological processes of the cell-body not directly connected with reproduction. In the Monera, which possess no nuclei, this is easily understood, but with the higher Protozoa, which normally always possess them, we could hardly have expected to find their influence so wanting. Neither can the shape of these creatures which, contrary to the formless masses of the Monera, is more or less regular or constant, be imputed to the influence of the nucleus, since the non-nucleated Actinophrys main- tain the normal form, 802 SUMMARY OF CURRENT RESEARCHES RELATING TO Nuclei of Lieberkuehnia.*—This fresh-water rhizopod was first described by Claparéde and Lachmann, and afterwards by Cienkowski, under the new name of Gromia paludosa. The observations of these authors are, however, HE. Maupas considers, far from being com- plete; and, moreover, are erroneous in some essential points. The form of the body is variable, and may be perfectly spherical, ovoid, oblong, or even fusiform. Hach individual can assume all these forms ; and when the same specimen is under observation during several days, it is seen to pass through all these changes. ‘These changes take place very slowly. ‘The carapace is very transparent, and is closely applied to the surface of the body, and changes with it. It also shares in the fissiparous division. It cannot, therefore, be regarded as a true carapace, like that of the Arcelle and the Diflugie, where the carapace is a product of chitinous secretion of the nature of a skeleton, and has a very different morphological value. In Lieberkuehnia the seeming carapace is in reality only an integument or ectosarc, which can be isolated by certain reagents from the endosare. The pseudopodia are capable of extending to a length of 2°26 mm., the body of the animal having a diameter of from 0°15 to 0:16 mm. The circulatory movement of the sarcode is one of the most rapid yet observed. The granules move through a space of 0:66 mm.a minute. The Infusoria which strike the meshes of their network are rendered motionless, and in this way Lieberkuehnia is able to capture large Infusoria, such as Paramecium aurelia. Sometimes the Infusoria are swallowed whole ; sometimes the sarcode of the pseudopodia envelopes them on every side, and constitutes around them a digestive vacuole, in which they are dissolved outside of, and frequently at some distance from, the body. They do not reach this till later on, when they are already assimilated to the substance of the pseudopodia in whose circulatory movement they disappear. The digestion takes place, and is finished, entirely outside of the body. With small Infusoria, such as Cyclidium glaucoma, the operation hardly lasts five or six minutes ; but Paramecium aurelia resists more than an hour. The sarcode of the mass of the body is in constant motion, not regularly in the same direction, like the cyclosis in Paramecium aurelia, but split up into currents with varying directions. This sarcode is hollowed out by numerous vacuoles of different volume and size, which are carried along by the currents, in which they are often seen to change their form, and sometimes to amalgamate one with another. They always end by coming to the periphery of the body, where they contract in a similar manner to that of the so-called contractile vacuoles. Lzeber- kuehnia is therefore not, as has been stated, destitute of these organs of excretion. It is, on the contrary, perhaps more richly furnished with them than many other Protozoa. There is simply this differ- ence, that the contractile vacuoles are neither permanent nor localized in any region of the body, every part of which may serve as a basis for their formation. * Comptes Rendus, xev. (1882) pp. 191-4. Ann. and Mag. Nat. Hist., x. (1882) pp. 410-13. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 803 Contrary also to what has been asserted, Lieberkuehnia likewise possesses a great number of nuclei, spherical, and measuring 4 p. It also increases by transverse division, as described by Cienkowski, but M. Maupas has seen individuals divide not only into two but into three. The body lengthened out into a long spindle, which, after the formation of two new peduncles bearing pseudopodia, became constricted at two points, and was thus divided into three nearly equal segments. One specimen, resulting from one of these divisions into three, developed, as soon as it was detached, a second peduncle bearing pseudopodia, situated at the opposite extremity to the one it already possessed. It continued thus to live with two places of emission of largely expanded pseudopodia. It was observed in this state for more than a day without any further changes taking place than those slow ones in the form of the body above-mentioned. In this, therefore, there was no preparation for a further fissiparous division, and the Lieberkuehnia, so constituted, with its two places of emission of pseudopodia situated at the two opposite extremities, would answer to the morphological type which has served to establish the family of the Amphistomina. It may be considered, therefore, one of those intermediate forms which connect separated families. Parasitic Protozoa.*—J. Kunstler describes five new parasitic Protozoa found by him. The first is a flagellate living in the intestine of the larva of Melolontha vulgaris, having a body which is elongated, flattened, rounded anteriorly and pointed posteriorly, and seems covered with longitudinal ribs more or less anastomosed ; it is often depressed at the sides, so as to have two lateral wings. At its anterior extremity are inserted six long striated flagella which give it a jerking move- ment. In well-developed individuals other filaments (sometimes fifteen in number) are frequently seen in the shape of a narrow spear- head, very much elongated and a little distorted, which are attached to the most diverse parts of the body, and are agitated with a con- tinual quivering movement. Near to the point of insertion of the flagella there is a buccal aperture which is connected, by means of a short and narrow canal, with a clear oval space occupying the central region of the body, which seems to be a digestive cavity. On the right of this region there is often.found a sort of vesicle whose appearance recalls that of a contractile vesicle. Another flagellate is frequently found with the preceding one, somewhat similar to it; but its body, which is not ribbed, is more globular and shorter, and it has only four flagella. The larva of Oryctes nasicornis is also the habitation of an organism smaller and more delicate than the preceding ; it dies and disappears very quickly in preparations. Only two flagella were seen. The intestine of the tadpole is often inhabited by a flagellate, which differs considerably from Trichomonas batrachorum Perty. It has six superior flagella, and a lower trailing filament; it has a rather * Comptes Rendus, xcy. (1882) pp. 347-9. 804 SUMMARY OF CURRENT RESEARCHES RELATING TO long tail, of striated muscular structure, larger than the flagella, and sometimes even double; its form is somewhat variable, and it is des- titute of the ridge and serrated erest which is seen in Trichomonas. In this same intestine was found a remarkable organism, Giardia agilis, which the author thinks ought to occupy an intermediate place between “certain Schizomycetes, such as Vibrio, Spirillum, and the Monads.” The body is formed of two clearly distinct portions: the upper and larger one has large vacuoles; the lower is much narrower, thicker, almost filiform, and resembling the large body of a Vibrio ; but its length is much greater, and it terminates in a fine point. Between these two regions there is a slight constriction. From the lower circumference of the former portion long flagella proceed in a downward direction, which often remain attached to the narrow portion for varying distances; two other flagella are inserted at the inferior free extremity. The narrow portion is very mobile and very flexible ; it constitutes a locomotive organ of very great power, and consequently the organism moves with remarkable activity. This kind of tail has an undulatory movement, similar to that of the tail of a tadpole, but at the same time it has a movement of “circum- duction,” and the combination of these two movements gives to it a helicoidal motion of remarkable vivacity. Intestinal Parasites of Oysters.*—A. Certes has found, in the oyster, Hexamita inflate, which is also found in the brackish waters of the region he studied; in addition to forms which presented two posterior filaments there were some observed that had four, and these are regarded as individuals undergoing longitudinal fission. The most interesting parasite was a new species of Trypanosoma — T. balbiani, which has at first sight the appearance of a large Spirillum. The action of the vapour of osmic acid, or iodized serum, and methyl- blue reveals the presence of a membrane, which is not rigid, but which appears to be contractile, and to obey the will of the animal; no mouth, anus, or contractile vacuole were to be detected in the interior, nor is there any nucleus or nucleolus; so that it is 2 Moneron with an undulating membrane. BOTANY. A. GENERAL, izcluding Embryology and Histology of the Phanerogamia. Structure and Movement of Protoplasm.t—G. Klebs gives a useful summary of the present state of our knowledge respecting the structure of protoplasm and the movements to which it is subject, and the connection between these two. He sums up by saying that, while we are still ignorant of the chemical composition of protoplasm, and of the mechanical forces which lie at the base of its mobility, it becomes * Comptes Rendus, xev. (1882) pp. 463-5. + Biol. Centralbl., i, (1881) pp. 577-94. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 805 more and more evident that the life of all living organisms depends on the vitality of this one and the same substance. Protoplasm of Compound Laticiferous Tubes.*—The presence of protoplasm in laticiferous vessels was not detected by the older botanists ; it has, however, been recognized in the compound latici- ferous tubes of the Euphorbiacer, Urticacezee, Apocynacere, and Asclepiader. E. Schmidt now adds to this list the following orders :— In the Cichoriacez, protoplasmic sac and nuclei were detected in Scorzonera hispanica and species of Sonchus; in Campanulacee, in Campanula ramosissima ; in Lobeliacez, in Siphocampylos bicolor ; and in Papaveracee, in Papaver. In Chelidonium the coalescence of the individual cells is imperfect ; and the protoplasmic sac and nucleus could be made out in each separate cell. The same is the case with Carica Papaya among Papayaceee. In Caladium marmoratum, among Aroidez, similar results were obtained. The so-called laticiferous tubes of Musacee are regarded by the author as rows of superposed tubes the contents of which are only locally in communication with one another; no nucleus or living protoplasmic sac could be detected in them. In many cases, and especially in the Musacee, it is very easy to mistake the coagulated latex for true protoplasm. In all the plants observed which contained compound laticiferous tubes, the protoplasm of the individual cells coalesces into a large *‘ symplast,” which retains its optical and colouring properties to the last without change. The nuclei also remain in the vessels after the fusion of the cells without any alteration of form or structure till the complete maturity of the organ. It is not probable that any division of the nuclei takes place after the fusion. The vitality of the proto- plasmic sac appears to be established by the following facts. In many cases the fusion takes place before the organ has attained its full size. If the mature vessels are injured, the protoplasm has also the power of repairing the wound, as in the multinucleated Siphonea, and in many pollen-tubes. This is effected by annular thickening ridges on the wall of the tube, which finally completely close up the wound, the substance of these thickenings being identical with that of the callus of sieve-tubes. An additional proof of the vitality of the protoplasm is that, after the growth of the wall of the vessel is com- pleted, it increases in thickness over its whole surface; and further, in the living plant, the latex cannot be coagulated by contact with water of imbibition. The latex, which is formed subsequently to the fusion, can also be regarded only as the product of a living protoplasm in the laticiferous vessels. Development of the Embryo-sac.j—As a sequel to his researches on the embryo-sac of Leguminose,{ L. Guignard gives an historical résumé of our knowledge of the structure of this organ in various natural families of plants, derived from his own observations and those of others. The following is an epitome of the general results :— The embryo-sac never arises from the fusion of two cells, but * Bot. Ztg., xl. (1882) pp. 435-48, 451-66 (1 pl.). t Ann. Sci. Nat. (Bot.) xiii. (1882) pp. 136-99 (5 pls.). t See this Journal, ante, p. 644. 806 SUMMARY OF CURRENT RESEARCHES RELATING TO always from the increase in size of one only. While this cell is usually the lower daughter-cell among those which arise from the mother-cell, it may be any one of the others, thus establishing a certain equivalence among them. In the latter case only are there one or more auticlinals. Sometimes the axile hypodermal cell of the nucellus divides, giving rise immediately, in contact with the epider- mis, to an apical cell, or initial cell of the calotte, and below to a subapical cell or mother-cell of the embryo-sac ; sometimes it is itself the mother-cell of the embryo-sac. Both these forms occur among monocotyledons and apopetalous dicotyledons, but among gamopeta- lous dicotyledons the former only has been met with. Among monocotyledons the mother-cell either remains undivided, or divides into a variable number of daughter-cells; in the former case it developes directly into the embryo-sac. Among apopetalous dicotyledons several mother-cells may develope, and in some cases this phenomenon seems to be constant; but ultimately there is never more .. than one embryo-sac. The mother-cell gives birth either to three daughter-cells in basipetal order, or to four secondary ones formed by bipartition of the primary daughter-cells, or even to a large number. Among gamopetalous dicotyledons the formation of four secondary daughter-cells seems to be normal. In the greater part of angiosperms the mother-cell of the embryo-sac is the lower daughter-cell; but there are exceptions to this rule. The tendency of the other daughter-cells to develope into the embryo-sac is manifested by the frequent development of two adjacent cells, the nuclei of which divide like that of the mother-cell of the embryo-sac. The walls of the daughter-cells are often thick, refringent, and present some analogy to those of the anther. The number of cells of the female apparatus and of antipodal cells is remarkably constant, apart from well-known exceptions, as Santa- lum, Gomphrena, and Loranthus; but their form and disposition are very variable. Among monocotyledons the synergide occupy the summit of the embryo-sac ; they are usually ovoid, and provided with a vacuole. The oosphere is inserted either at the same level at the summit, or lower down laterally. The antipodals often remain very small, or sometimes become almost as large as the sexual cells; occasionally they even divide. ‘The fusion of the polar nuclei often takes place towards the centre of the embryo-sac, rarely in its upper part. Among apopetale the synergide are situated at the summit, and are rarely without a vacuole when mature. The oosphere is dis- tinguished by its nucleus, situated at the base; it is inserted laterally, and generally descends much lower than the two synergide. The antipodals are sometimes small, sometimes large. The fusion of the polar nuclei takes place towards the centre or towards the apex. Among gamopetale the synergide, placed on each side of the plane of symmetry, have a characteristic form; in the majority of cases they are elongated, and contract to a point at the summit; they have a large vacuole. The oosphere is always inserted laterally, and its nucleus is larger than that of the synergide. The antipodals are rarely ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 807 placed at the same level; more often they are superposed; sometimes they multiply, and form a tissue of a special nature. The fusion of the polar nuclei takes place towards the centre of the sac, or higher up, near the oosphere. The author then traces the genetic history of the embryo-sac of angiosperms through the various classes of the higher eryptogams, and finally through the gymnosperms. The pollen-grain of gymnosperms, in which Strasburger has demonstrated the existence of a single partition, presents a close analogy to the microspore of Selaginella. One of the two cells developes into the pollen-tube, and represents an antheridium ; the other is equivalent to a rudimentary male prothal- lium. The naked cells, observed by Hofmeister and Strasburger at the extremity of the pollen-tube, may be compared to the mother-cells of antherozoids, and complete the analogy, which is rendered more evident by comparing the mode of formation of the microspores of vascular cryptogams with that of the pollen-grains of gymnosperms. The researches of Strasburger and Elfving have shown the existence of a similar division-wall in the pollen-grain of angiosperms. Two cells are thus formed ; one of these, the vegetative cell, further divides into a prothallium of two or three cells; the other, the nucleus of which has not been observed to divide, except in the Cycadex, becomes the pollen-tube; the nucleus, situated at the extremity of the tube, appears to play an important part in the process of fecundation. As regards the homology of the female organs, the author contends that the facts support Strasburger’s theory that the embryo-sac is the homologue of the macrospore of the higher cryptogams, and not the nucellus, as Warming maintains, a view which is inconsistent with the remarkable phenomenon of the fusion of the polar nuclei. The female prothallium is represented in gymnosperms by the endosperm, in angiosperms by the antipodals and the two polar nuclei; the synergide are endosperm-cells endowed with a special function; and the endosperm of angiosperms, which is formed only after fecundation, by division of the secondary nucleus of the embryo-sac, is the result of the resumption of an interrupted development. Development of the Embryo in Lupinus.*—An apparent anomaly in the embryogeny of certain species of Lupinus is explained by L. Guignard as due to differences in the structure of the ovule. The species of the genus may be divided into two groups, according to the number of ovular integuments; one group, represented by L. poly- phyllus, having only one integument; the other, represented by L. luteus, having two; and this is correlated with a difference in the structure and development of the suspensor or proembryo. The number of pairs of cells of which the suspensor is composed, and con- sequently the length of this organ, varies with the species; but in all those which have only one integument, it finally becomes disinte- grated, and the cells which constituted it arrange themselves on the median line from the micropyle to the embryo, which is always * Bull. Soc. Bot. France, xviii. (1881) pp. 231-5. See this Journal, ante, p. 644. 808 SUMMARY OF CURRENT RESEARCHES RELATING TO situated at the base of the cavity, at about equal distances from the chalaza and the micropyle. These disintegrated proembryonie cells were taken by Hegelmaier for a special organ, peculiar to Lupinus, formed before fertilization. In the species with two integuments this phenomenon is not presented, owing to the permanent coherence of the cells of which the suspensor is composed. Homology of the Ovule.*—F. Pax describes in detail instances of phyllody of the carpels in Aquilegia vulgaris and formosa, with especial reference to the genetic morphology of the ovule. He comes to the same conclusion as Brongniart and Celakovsky,{ that the two integu- ments of the ovule together constitute a leaflet, on the upper side of which the nucellus is equivalent to a metablast. The identity of this leaflet with a pinnule of a fertile fern-frond is evident; and the homologies of the parts may be expressed as follows :— Fern. Ovule. Spore. Macrospore. Embryo-sac. Macrosporangium. Nucellus. Sorus. Several nucelli. Pinnule. Ovular leaflet. Reproductive Organs of Cycadee.t{— An examination of the reproductive organs of several species of Cycadex leads M. Treub to the following general conclusions :— Each scale of the female cone (in Ceratozamia longifolia) bears two sporangiferous lobes, each of which gives birth to a macrosporangium. he macrosporangium can be detected in the interior of the lobe before any external differentiation is perceptible. In each macrosporangium can be recognized, at a later period, the three following parts :— (1) the reproductive or primordial cells; (2) in the interior an external parietal layer; and (3) an internal compound parietal layer. There is, in Ceratozamia, only a single macrospore mother-cell; and this does not divide, as in cryptogams; it produces the single macro- spore, in the same way as the embryo-sac is in general formed. Shortly after the first appearance of the macrosporangium within the sporangiferous lobe, this latter produces, on its apex, turned towards the axis of the cone, two new formations, the nucellus and the integu- ment. The nucellus owes its origin to one or two hypodermal layers of the macrosporangium; the integument is elevated on the lobe around the nucellus. With regard to the homology of the parts—if Ceratozamia is to be taken as a normal type of the Cycadez, as seems most probable—the macrosporangium of Cycadex, developed within the sporangiferous lobe, is perfectly homologous to a sporangium of Ophioglossum ; the nucellus and the integuments are new formations which find no homologue in cryptogams. In the Cycadex, therefore, neither the nucellus nor the ovule represents a sporangium; the sporangiferous * ¢Hlora,’ Ixv. (1882) pp. 306-16 (1 pl.). + See this Journal, ante, p. 648. t+ Ann. Sci. Nat. (Bot.) xii, (1882) pp. 212-82 (7 pls.). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 809 lobes must rather be compared to the “ovular mamelon” in angio- sperms. The sporangiferous lobe, bearing the nucellus and the integuments, may be regarded as presenting the transition from the sporangium of Ophioglossum to the ovule of angiosperms. Although the Cycadez are undoubtedly the most ancient phanero- gams, and the most nearly allied to -eryptogams, M. Treub does not consider it probable that any existing gymnosperms represent the actual transition from eryptogams to angiosperms; the forms we now have are probably derived from those which actually constituted the connecting link. Cell- and Nuclear Division in the Formation of the Pollen of Hemerocallis fulva.*—According to E. Tangl, the young pollen mother-cells of Hemerocallis fulva have comparatively large finely granular nuclei, containing several nucleoli which are distinctly coloured by methyl-green or Beale’s carmine. At a later period the number of nucleoli diminishes, so that each nucleus has only one or less often two, which are no longer coloured by methyl-green, while their colouring by Beale’s carmine remains unchanged. At the same time the originally regular distribution of the granules is altered. They at first form a network, and afterwards a thin layer on the wall of the nucleus, with a larger central group, and an anastomosing net- work between them. ‘To the hyaline substance between the granules Tangl applies Flemming’s term, “intermediate substance.” At this stage the structure of the nucleus is completely destroyed by alcohol ; by treatment with acetic acid and methyl-green the granules are coloured a dark blue-green. Ata later period the regularly distri- buted small granules of the nucleus are replaced by larger granular structures which behave in the same way towards reagents. Subse- quently the nuclear membrane disappears, and the intermediate substance assumes a granular character, exactly resembling that of the surrounding protoplasm. This is followed by a new nucleus of irregular outline, destitute of membrane, and nearly entirely composed of granular substance which takes the pigment, and which is probably derived genetically from a coalescence of the granular structures with the nucleolus of the earlier nucleus. If two nucleoli are originally present, one of them appears not to take part in this coalescence, but to remain imbedded in the protoplasm. From the new nucleus is formed the nuclear plate, consisting in most cases of granules somewhat elongated in the direction of the axis of the spindle, less often of a continuous disk with teeth directed towards the pole, and lying in a clear hyaline portion of the protoplasm. The daughter-nuclei are at first roundish and finely granular; they subsequently change their form from unequal growth, their contents becoming at the same time differentiated into granules, intermediate substance, and membrane. The granules afterwards all lie on the membrane, on which they form a network with polygonal meshes. The formation of the nuclear plates in the secondary nuclei is preceded by a considerable diminu- * Denkschr. K.K. Akad. Wiss. (Wien), xlv. (1882) 22 pp. (4 pls.). See Bot. Centralbl., xi. (1882) p. 169. 810 SUMMARY OF CURRENT RESEARCHES RELATING TO tion of the intermediate substance and of the entire volume of the nucleus. The cell-plates are formed in the same way as in other pollen-grains; but the arrangement of the daughter-nuclei differs somewhat from the normal, since they lie either in a plane or cross-wise. The special mother-cells sometimes undergo subsequent divisions, resulting in the formation of smaller pollen-grains. Comparing this development with that of the animal ovum, the author considers the small globular structures or nucleoli, which often accompany the primary nucleus of the mother-cells when reduced by retrogressive metamorphosis, to be the homologue of the elements of the germinal vesicle which are not active in the formation of the bi-aster. Structure and Growth of the Cell-wall.*—Professor H. Stras- burger’s most recent publication is divided into the following sections :—The origin and growth in thickness of the cell-wall; the growth of starch-grains; the relationship of swelling to anatomical structure ; the formation of membrane in the animal kingdom; the double refraction of organized structures; the molecular structure of organized bodies; the assimilation of carbon; the function of the cell-nucleus; the permeability of the cell-wall ; and the behaviour of the cell-nucleus in the process of sexual reproduction. The following are some of the more important results at which he has arrived :— With regard to the intimate structure of organized bodies, Prof. Strasburger entirely dissents from Naegeli’s micellar hypothesis. This hypothesis was based upon the phenomena of “ swelling-up” which are so characteristic of organized bodies, and upon the optical properties which certain of these bodies possess. Professor Stras- burger points out that swelling-up may be as well ascribed to the taking-up of water between the molecules of the body as to its being taken up between Naegeli’s micelle. He shows also that the double refraction of organized bodies, such as cell-walls and starch-grains, depends upon their organization as a whole; for when once their organization is destroyed, their double refraction is lost, a result which cannot be explained on the micellar theory, since the particles of the disintegrated micelle would, like particles of broken crystals, still retain their power of double refraction. According to Stras- burger the molecules of an organized body are not aggregated into micellz which are held together by attraction, but are linked together, probably by means of multivalent atoms, by chemical affinity, in a reticulate manner. Swelling-up is then the expression of the taking- up of water into the meshes of the molecular reticulum, where it is retained by intermolecular capillarity. The more extensible the reticulum, that is, the more mobile the groups of molecules within their position of equilibrium, the greater the amount of swelling-up. The limit is reached when the chemical affinity of the molecules and the force of the intermolecular capillarity are equal; if the latter * Strasburger, H., ‘ Ueber den Bau u. das Wachsthum der Zellhaute.”? 264 pp. (8 pls.) Jena, 1882. Cf. also article by Dr. 8. H. Vines in ‘ Nature, xxvi. (1882) p. 595, and Bot. Centralbl., xi. (1882) pp. 269-83. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 811 exceed the former at any moment, the result is the destruction of the molecular reticulum, or, in other words, of the organization. Pro- toplasm differs from other organized bodies in that the grouping of its molecules is undergoing perpetual change, the result of this mole- cular activity being the phenomena which we term vital. The growth in thickness of cell-walls and of starch-grains takes place, according to Professor Strasburger, by the deposition of succes- sive layers ; in opposition to Naegeli’s view, that the mode of growth was intussusceptive, with subsequent differentiation of layers. Even the surface-growth of cell-walls is not, in his opinion, intussusceptive, but is merely due to stretching. With reference to the mode of formation of the cell-wall and of the thickening-layers, Strasburger agrees with the view of Schmitz that the cell-wall is formed by the actual conversion of a layer of the protoplasm, that is, chemically speaking, by the production of a layer of cellulose from a layer of proteid. When a mass of protoplasm is about to clothe itself with a membrane, the peripheral layer becomes densely filled with minute protcid bodies, the microsomata, and this layer then becomes converted into cellulose. The wall of a young wood-cell of Pinus, for instance, is clothed internally with a layer of protoplasm filled with microsomata, which are arranged in spiral rows; the microsomata then gradually disappear, and the layer of protoplasm is found to be replaced by a layer of cellulose, which presents spiral striation corresponding to the previously existing rows of microsomata, and which constitutes a thickening layer of the cell- wall. In cells the walls of which become much thickened, the whole of the protoplasm may be gradually used up in this way. Again, the wall of pollen-grains and of spores is formed from a peripheral layer of the protoplasm which contains abundant microsomata. Its subse- quent growth, and especially the development of the asperities which it commonly presents, is effected by the surrounding protoplasm which is derived from the disorganized tapetal cells ; this is especially well shown in the development of the epispore of Equisetum and of Marsilia. When an intine or endospore is present, it is produced like the outer coat from a peripheral layer of the protoplasm of the pollen-grain or spore. Further, the septum which is formed in the division of a cell is produced in the same way. The cell-plate, like the peripheral layer of the protoplasm of a young pollen-grain, con- tains microsomata which disappear, and it is then converted into a plate of cellulose. Finally, the successive layers of a starch-grain are produced by the alteration into starch of layers of proteid- substance derived from the starch-forming corpuscle (amyloplast). Professor Strasburger next points out that the starch which makes its appearance in the chlorophyll-corpuscles under the influence of light, is derived from the proteid of the corpuscles by dissociation. The formation of this starch is therefore not the immediate product of the synthetic processes going on in the chlorophyll-corpuscles, but only a secondary product. ‘he processes in question produce proteid. Professor Strasburger is inclined to accept Erlenmeyer’s hypothesis, that methyl aldehyd is formed in the chlorophyll-corpuscles from 812 SUMMARY OF CURRENT RESEARCHES RELATING TO carbon dioxide and water, and to believe that by polymerization a substance is produced which can combine with the nitrogenous resi- dues of previous dissociations of proteid to reconstitute proteid. He does not agree with the suggestion of Loew and Bokorny that the methyl aldehyd may combine with ammonia and sulphur to form proteid de novo. Lastly, Professor Strasburger makes a suggestion as to the probable physiological significance of the nucleus. He points out that the nucleus cannot be regarded as regulating cell-division; for instances are known of cell-division taking place without previous nuclear division, and, conversely, of nuclear division taking place without cell-division. He is of opinion that the nucleus plays an important part in the formation of proteid in the cell. This view is founded upon the facts that one or more nuclei have been found to be present in the vast majority of plant-cells, that the nucleus is, as a general rule, the most persistent protoplasmic structure, and that it gives the various proteid reactions in a very marked manner. Order of Appearance of the Primary Vessels in Aerial Organs.* —A. Trécul has collected the results of a long series of observations on the formation of the first vessels in the stem, leaves, and floral organs of the following plants :—Anagallis arvensis, Primula elatior, officinalis, grandiflora, and other species, Lysimachia, Ruta, Lupinus, Astragalus, Galega officinalis, Foniculum vulgare and dulce, Iris, Allium, Funkia, Hemerocallis, and a number of grasses. For the details of the observations reference must be made to the paper itself. Among the more important of the general results, M. Trécul is led to contest the usual statement that all stems and leaves branch from below upwards, and especially Sachs’ explanation of the pinnate and other forms of division in leaves as referable to a scorpioid type. The order of appearance of the vascular bundles shows, on the con- trary, that there are two kinds of pinnate leaves, basifugal or acropetal, and basipetal; and the same is true of leaves where the segmentation is not carried so far ; and also of the secondary divisions of the leaflets themselves. The basipetal development may also be altogether independent of any scorpioid arrangement. Collenchyma,t—An examination of the structure and mode of formation of collenchyma in a large number of plants, made by C. van Wisselingh, confirms the general statement of Sachs, that this tissue has its origin directly in the fundamental tissue. In all the plants examined by him the vascular bundles were already in exist- ence in the procambial condition before the formation of the collen- chyma. He found no instance of the common origin of collenchyma and mestome described by Haberlandt and Ambronn. The number of layers of cells found in the youngest state between the epidermis and vascular bundles varied from two to six, or even more. Most commonly, in the tissue intermediate between the epidermis * Ann. Sci. Nat. (Bot.) xii. (1882) pp. 251-381. + Arch. Néerland. Sci., xvii. (1882) pp. 23-58 (2 pls.). Cf. this Journal, i. (1881) p. 768. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 813 and vascular bundles, cell-division plays, in the first place, the most important part, and afterwards the collenchymatous thickening ; more rarely the two processes are simultaneous. The period when the thickening begins to manifest itself prominently depends on the mechanical function which the collenchyma has to fulfil in the young organs of the plant. It is not uncommon for the thickening of the cell-walls to be accompanied by rounding off and disappearance of the intercellular spaces. The septated collenchymatous fibres, which terminate at the extremity of the stem in Lamiwm purpureum and Aesculus japonica proceed from parenchymatous cells. Haberlandt found, on the con- trary, that in Lamium purpureum, Atherurus ternatus, Cucurbita Pepo, and Tradescantia erecta, the fibres originate from a generating pros- enchymatous tissue formed by repeated longitudinal division of merismatic mother-cells. In Chenopodium album the same observer always found collenchyma originating from parenchyma. In none of the plants examined was the author able to detect a closer genetic connection between the cells of the collenchyma them- selves than between them and the adjacent parenchymatous cells. Sanio, on the contrary, states, in the case of Huonymus latifolius and Peperomia blanda, and Haberlandt in that of Tradescantia erecta, that the collenchyma is derived from a single hypodermal layer of cells. Stomata in a Fossil Plant,*—In a large series of fossil plants obtained from the Turonian beds of the cretaceous formation from the neighbourhood of Bagnois (Gard) R. Zeiller finds very well-pre- served wood of a conifer closely allied to the Thuyites Hoheneggert Kttings. of the Wealden. In the ultimate branches or leaves, the stomata may be exceedingly well made out; and they are remarkable for having, instead of a single fissure, an opening in the form of a star with four or five rays. The stomata are formed of four, or less often of five cells arranged in a rosette, the walls of which radiate towards a central point, but leaving an orifice in the centre, in length about one-third or two-fifths of the rays. 'The mechanism by which the opening is produced is the same as in ordinary stomata, except that four or five cells instead of two share in it. The stomatic orifice occupies the bottom of a slight depression, though not so well marked as in the allied recent Callitris quadrivalvis, Libocedrus decurrens, and Frenela, and are usually surrounded, as in them, by a slightly projecting margin of cuticle. The stomata are arranged regularly in rows over the whole surface of the leaf. Spiral Cells in Crinum and Nepenthes.j—A. Trécul and L. Mangin both describe, as the result of separate investigations, the large spiral cells found by the first in several species of Crinum, by the last also in Nepenthes phyllamphora. In Crinum americanum they are dispersed through all parts of the parenchymatous tissue of both faces of the leaf, into the immediate neighbourhood of the large inter- * Bull. Soc. Bot. France, xxviii. (1881) pp. 210-4. t+ Ann. Sci. Nat. (Bot.) xiii. (1882) pp. 200-7 and 208-16 (1 pl.). Ser. 2.—Vot. II. a 814 SUMMARY OF CURRENT RESEARCHES RELATING TO cellular spaces, and of the fibro-vascular bundles, usually collected together into groups, often in long longitudinal bundles. They are greatly elongated cells, from 0°5 to even 13 mm. in length, and from 0-025 to 0:06 mm. in diameter, and occasionally are even branched. They contain nothing but air, and are surrounded by ordinary paren- chymatous cells. Their form and disposition differ in other species of Crinum, but are nearly uniform in the same species. They were not found by M. Trécul in any part of the plant except the leaves; but M. Mangin finds them also in the cortical tissue of the stem, where they attain a still greater size. M. Mangin considers them as analogous to internal hairs. In Nepenthes phyllamphora similar cells occur in the stem, the -leaves, and the pitchers, but always isolated. The parenchyma which contains them is here compact, and not furnished with intercellular passages. Structure of Secretory Glands.*—An examination of the internal glands in a large number of plants has led Dr. F. R. v. Héhnel to the following general results :— The glands of the Myrtacez, those Leguminose which were ex- amined (Amorpha, Hymenea, and Trachylobium), the Hypericinee (Hypericum and Androsemum), and of Oxalis, Lysimachia, Myrsine, Ardisia, and Peganum Harmala are schizogenous; while (except Peganum Harmala) those of the Rutacez and their allies (Callionema, Citrus, Toddalia, Boronia, Correa, and Ptelea) are lysigenous. The secretion-cavity is always completely closed in lysigenous glands: while in schizogenous glands there are three distinct varieties :—(1) completely closed, which is the ordinary case; (2) those which at length burst from the copious excretion of fluid (Oxalis floribunda) ; and (8) altogether open ; these are properly only secretory portions of ordinary air-containing intercellular spaces (Peganum Harmala and Lysimachia ephemera). Glands which are buried in the tissue are either entirely dermato- genous (Amorpha, and those Myrtaces where the glands are im- mediately beneath the epidermis), cr are in their outer portion formed out of the epidermis (Citrus, Dictamnus, and probably Correa, Toddalia, and many other genera of Rutacez), or their origin is altogether independent of the epidermis (all deeply buried glands, as those of Eucalyptus, Hypericum, Ardisia, Myrsine, &c.). Juysigenous glands appear to be generally formed from several cells which have become separated before the first appearance of the gland (Callionema and Citrus); while schizogenous glands are almost always formed from a single cell (Myrtacexe, Lysimachia, Hypericum, and Myrsine), very seldom from several (Amorpha). When mature the distinction between schizogenous and lysigenous glands is always observable. The former always have an epithelium sharply defined on the inside, and usually more or less clearly dis- tinguishable from the surrounding cellular tissue by the nature of the cell-wall aud of the cell-contents ; it is from this that the fluid * SB. K.K. Akad. Wiss. (Wien), lxxxiv. (1881) pp. 565-603 (6 pls.). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 815 is excreted, and it is entirely wanting in lysigenous glands; the latter are usually surrounded by partially absorbed cells which are not sharply distinguishable from the surrounding tissue. In glands which originate from the epidermis (Amorpha, Myrtus, and Eugenia), it is not uncommon that instead of growing into the parenchyma, they become glandular, warty, or conical trichomes; which appears to indicate that internal epidermal glands originate as trichomic glands; the latter being phylogenetically the older. The schizogenous glands of Hymenea and Trachylobium contain copal ; the hard copal of Trachylobium having undoubtedly a similar origin. In Ardisia crenulata are peculiar schizogenous secretory organs, formed locally out of the medulla of the veins of the margin of the leaf, and which contain an albuminoid substance; of these a careful examination was made. The same species also possesses secretory organs, which from their origin and structure must be regarded as a coalescence of secretory tubes. The mucilage-tubes of Abies possess albuminoid crystalloids in the interior of the mass of mucilage formed in the protoplasm. A description is given also of the origin, structure of the wall, and nature of the contents of the secretory tubes of vodia glauca, Rhamnus, Aonium tortuosum, Mesembryanthemum, Physostegia vir- giniana, Calycanthus, Cesalpinia echinata, &c. Oil and mucilage-tubes also occur in the wood of some Laurinez. Sphero-crystals.*—G. Kraus records the discovery of sphero- crystals in Ptelea trifoliata, Conium maculatum, and Aithusa, apparently identical in composition with those previously detected in Cocculus laurifolius. In Ptelea they occur in the leaf only ; in Conium also in the stem, flower-stalks, fruits, &c.; but in all cases in the epidermis only. They usually have the form of hemispheres attached to the wall; and are radiate or even spined. As in Cocculus, they are not found in every epidermal cell, but in groups in adjoining cells, and attached to the adjacent transverse walls. They are insoluble in cold or boiling water, and in dilute mineral or organic acids; soluble in concentrated sulphuric acid with a golden yellow colour, and in potash-ley or hot nitric acid. The reactions indicate a probability that they are composed of hesperidin. Their insolubility in alcohol shows that they cannot consist of any compound of conia. Respiration of Detached Shoots.;—It is an established fact that a sprig of a plant, if placed for some hours in an atmosphere of car- bonic acid and then removed and placed in the dark, exhales a more than normal amount of carbonic acid. This has been stated to be due simply to the giving up of carbonic acid which has been taken in in excess, but not assimilated. J. Borodin combats this conclusion with the following arguments :— The activity of respiration of a detached twig is not constant, even when the conditions are constant; it becomes less in the dark. This * Ber. Naturf. Ges, Halle, 1881, pp. 41-3. t+ Mem. Acad. Imp. Sci. St. Petersbourg, xxviii. (1881) No. 1. Cf. Natur- forscher, xiv. (1881) p. 463. a 12 816 SUMMARY OF CURRENT RESEARCHES RELATING TO diminution is due to gradual exhaustion of the supply of carbo- hydrates, for if carbo-hydrates are assimilated afresh the activity of respiration takes a new start. That this renewed activity is caused by assimilation and not by simple absorption of carbonic acid is shown by the fact that (1) both light and carbonic acid are necessary to the commencement of this condition; (2) insolation is useless without carbonic acid; (8) an atmosphere rich in carbonic acid is useless without light ; (4) a small proportion of carbonic acid is sufficient, if combined with light; (5) absorption of oxygen undergoes increase after insolation ; (6) the intensity of the light is of importance ; sunlight is best ; (7) the more refrangible rays take part in the action. Absorption of carbonic acid may take place to a slight extent, in addition to the assimilation; but it only occurs after a sojourn in a richly carbonized atmosphere, and it passes off in from one to two hours. The solid parts take an active part in the absorption ; seeds apparently absorb as much (in relation to their weight) in a dry as in a soaked state. Dry seeds absorb only insignificant quantities of hydrogen. Physiological Functions of the Tissues of Plants.*—G. Haber- landt occupies a section of Schenk’s ‘ Handbook of Botany ’ (‘ Encyklo- pedie der Naturwissenschaften’) with an exhaustive account of the various kinds of vegetable tissue, and of the parts which they fulfil in the economy of the plant; treating the subject from a Darwinian point of view, i.e. regarding the anatomical structure and arrange- ment of tissues as aseries of phenomena of adaptation. The following is his classification of tissues :-— : J. Epidermal System. 1. Epidermis. 2. Cork. 3. Bark. II. Skeletal System. 1. Bast and libriform. 2. Collenchyma. 3. Scleren- chyma (?). III. Nutritive System. 1. Absorptive System (Epithelium of the root, root- hairs, &c.). 2. Assimilative System (Chlorophyll-parenchyma ; pali- sade tissue). 8. Conductive System (Conducting parenchyma; con- ducting bundles [mestome, hadrome, leptome] ; parenchyma-sheaths ; laticiferous vessels). 4, Aerative System (Tracheal System (?); air-conducting intercellular spaces with their orifices [stomata and lenticels]). Local structures. Endoderm; thickened vascular bundle- sheaths; glandular, oil-, mucilage-, and gum-passages, &c. The following definitions are also given: Protoderm consists of * Schenk’s Handb. der Bot., ii. pp. 557-693 (28 woodcuts). Breslau, Tre- wendt, 1882. See Bot. Centralbl., xi. (1882) p. 158. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 817 the peripheral layer of merismatic cells ; Cambium of parenchymatous cells with narrow cavity, usually united into longitudinal bundles ; Fundamental parenchyma is the tissue which remains after the differ- entiation of the protoderm and cambium. Chlorophyll and Hypochlorin.*—A. Tschirch gives the follow- ing as the results of a series of fresh observations on chlorophyll and its derivatives. Pringsheim’s hypochlorin (at all events as regards the greenish yellow needles) is a product of the action of acids on the colouring matter of chlorophyll, and can be produced outside the plant in the well-known crystals. To distinguish this from the possible colour- less matrix, which has, however, not yet been satisfactorily separated, the author calls it a-hypochlorin. It is identical with Hoppe-Seyler’s chlorophyllan, and with the precipitate which appears spontaneously when solutions of chlorophyll have stood for some time. All the substances belonging to this group are products of oxidation of a portion of the chlorophyll. Chlorophyllan, or a-hypochlorin, can easily be obtained pure in the form which Pringsheim has described, by laying leaves of grass which have been freed by ether from oil and wax, for some days in hydrochloric acid, carefully washing out the acid, and extracting with boiling alcohol. When the filtrate cools abundance of a-hypochlorin precipitates, which can be increased by distilling off a portion of the alcohol. It crystallizes in the form of dark brown (or greenish in incident light) radiating needles; the whip-like form results from the impurity of the solution. The formation of chlorophyllan in the living plant is due to the presence of organic acids. With the exception of water-plants, the author found none in which the cell-sap has not a distinct acid reaction. When the proportion of acid is only small, the chloro- phyllan is only formed by allowing the extract to stand for a long time; carbonic dioxide produces it at once. The extracts of strongly acid leaves like those of Aesculus or Rumex, deposit chloryphyllan simply on cooling. The formation is completely prevented by giving an alkaline reaction to the extract. It is probable that many of the described modifications of chloro- phyll depend on the variation in the proportion of acid present in the cell-sap, and in the variable solubility of the acids in the solvents employed. The cause of the absence of hypochlorin from the chlorophyll- grains in many plants, even when lying in an acid cell-sap, is the fact which Tschirch has established, and which had already been assumed on theoretical grounds by Naegeli and Pfeffer, that every grain of chlorophyll is surrounded by a colourless hyaloplasmic layer, which may frequently be clearly made out, especially in water- plants. In the living state this hyaloplasmic layer is not permeable to acids; it is consequently only after death that the acid cell-sap enters and produces a-hypochlorin. In a subsequent communication Tschirch further criticizes Prings- * SB. Bot. Ver. Prov. Brandenburg, 1882, pp. 41-5, 124-34. 818 SUMMARY OF CURRENT RESEARCHES RELATING TO heim’s arguments, and agrees with his conclusion that the first product of assimilation must be a substance containing less oxygen than had previously been supposed. There is also a good deal in favour of the view that this substance is Pringsheim’s hypochlorin ; but on the whole the author considers 1t more probable that it is a product of decomposition of the colouring matter of the chlorophyll, formed only on the addition of reagents. The statement of Prings- heim that ‘‘in those cases where the chlorophyll-grains assume large dimensions, as in bands, plates, &c., it is easily seen that the hypo- chlorin does not appear everywhere where there is colour, but is localized to certain spots,’ is not confirmed by Tschirch’s observa- tions. Function of Chlorophyll.*—Professor N. Pringsheim’s latest contribution to this subject is chiefly occupied with an historical résumé of our knowledge, and a reply to objections from various sources to his previously published views, to which he adheres in all essential points. Pringsheim does not agree with the view of some other investigators | that the first product of assimilation is formic aldehyde. This is not in accordance with the fact that in the light the volume of oxygen evolved is equal to that of carbon dioxide de- composed, taken into consideration in connection with the simultaneous respiration of the plant. The total result can only be explained by the product of assimilation being a compound which contains a smaller proportion of oxygen than formic aldehyde. Vitality of the Chlorophyll-pigment.t—G. Kraus preserved fruits of Cucurbita melanosperma in an ordinary sitting-room for more than three years, at the end of which time mould began to appear on them. The non-chlorophyllaceous cells were then found to contain proto- plasm and other cell-contents apparently unchanged. In the chloro- phyllaceous cells, on the other hand, the chlorophyll-grains were transformed into green balls, having undergone a change similar to that of the autumn colouring of the leaves of the horse-chestnut. The colouring-matter of the chlorophyll appeared, however, to be entirely unchanged. An alcoholic extract gave the typical spectrum of chlorophyll with seven bands. Action of various Gases on Plants.s—W. Detmer has experi- mented on the influence of various gases on living plants. He found the effect of nitrous oxide, hydrogen, and carbonic acid to be very similar, hindering the further development of seeds and seedlings, and preventing heliotropic curvatures and the greening in the light of etiolated parts of plants. Chloroform also acted disadvantageously on growth; but respiration was not suspended in an atmosphere contain- ing much chloroform. * Pringsheim’s Jahrb. fiir wiss. Bot., xiii. (1882) pp. 377-490. Cf. this Journal, lii. (1880) pp. 117, 480; i. (1881) p. 479; ante, p. 220. ¢ See this Journal, ante, pp. 361, 362, 526. t Ber. Naturf. Ges. Halle, 1881, pp. 43-5. ei ae Jahrb., xi. (1882) p. 213. See Naturforscher, xv. (1882) p. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 819 Power of Plants to absorb Carbonic Oxide.* — L. Just has subjected Azolla caroliniana and Lemna gibba to a series of experi- ments for the purpose of determining whether plants can assimilate CO in the place of CO,. He finds that this gas is not absorbed by green plants; but that it is injurious only when its proportion in the atmosphere exceeds 10 per cent. It then prevents the formation of chlorophyll, and hinders assimilation and growth. If the gas is then removed, the plant may partially recover. Chlorophyll-grains have no power of absorbing carbonic oxide. Control-experiments were also made on the same plants under the same circumstances with pure air entirely free from carbonic acid gas and with air containing the normal amount of this gas. Formic Acid in Plants.t—In addition to the somewhat doubtful occurrence of free formic acid in the stings of the stinging-nettle and similar structures, A. Vogel records an undoubted instance in a powder which occurs in commerce made from the hairs of Negretia pruriens. The quantity, however, is very small, and the author thinks that, both in this case and in that of the irritating fluid of the stinging-nettle, the irritation is partly mechanical, due to the large amount of silica present in the part of the hair which enters the wound. The presence of formic acid in the vegetable kingdom is easily explained by the oxidation of albuminoids and of carbonic acid, and by the action of oxalic acid on glycerine. In addition to the stinging- nettle, it has been detected in the leaves, bark, and wood of the spruce fir, in the sap of the house-leek (Sempervivum tectorwm), and in the fruits of the tamarind, and of Sapindus Saponaria. Its well-known occur- rence in honey, where it is accompanied by other vegetable acids, probably lactic, malic, and oxalic acids, is due to its excretion from the stinging-gland of the bee. The proportion present in new sugar averages about 1 percent. It has the effect of hindering fermentation, and hence promoting the preservation of the honey. Function of Lime-salts{—H. de Vries points out that there is hardly any experimental evidence in support of the ordinary theory of the part played in the life of the plant by calcium oxalate, viz. that the oxalic acid is a product of the albuminoids, and that its function is to decompose the calcium phosphate and sulphate, the lime being the carrier of phosphoric and sulphuric acids to the plant. On the contrary, the formation of albuminoids and of calcium oxalate appears to go on quite independently of one another, while protoplasm has an alkaline reaction, and cannot therefore contain free phosphoric or sulphuric acid. The fact that the amount of lime deposited in the leaves increases continually with their age appears to point to the conclusion that it is an excretory product. The ordinary theory that calcium oxalate * Forsch. aus dem Geb. der Agriculturphysik, v. p. 60. See Naturforscher, xv. (1882) p. 336. + SB. Math.-phys. Klasse Miinch. Akad., 1882, p. 345. See Naturforscher, xy. (1882) p. 355. Cf. Pharm. Journ., xiii. (1882) p. 269. t Vries, H. de, ‘ Ueber die Bedeutung der Kalkablagerungen in den Pflanzen. 34 pp, (Berlin, 1881). See Bot. Centralbl., x. (1882) p. 194. 820 SUMMARY OF CURRENT RESEARCHES RELATING TO is insoluble in the cell-sap does not rest on a satisfactory basis; in some cases, on the contrary, it would certainly appear to be dissolved, and in this state to pass through the cell-wall. It is, however, soluble with difficulty ; and the function of oxalic acid seems to be to get rid, in this form, of what would otherwise be an injurious excess of lime. Lime and oxalic acid are both present in soils in greater quantity than is needed by the plant; and their excess is consequently excreted by the plant in an insoluble form, or at least one that is soluble only with difficulty. Function of Resinous Substances.*—H. de Vries has investi- gated this subject in detail, especially in reference to the terebenthin and resin produced by conifers; and urges arguments in opposition to the generally accepted view that these substances are simply waste products of an excretory nature. Terebenthin is the substance most rich in carbon which occurs in conifers, and its production requires, in consequence, the consumption of a relatively large quantity of assimilated substances, especially of glucose, from which it is probably formed only by a long series of chemical transformations ; and its production can in no sense be regarded as analogous to that of gum in wounded cherry or plum trees. It must, on the contrary, be looked on asa normal and important function in the life of conifers. As long as the reservoirs in which it is formed remain closed, this resin undergoes no change; but whenever the organ is wounded, it flows out in the form of a thick viscid mass, which gradually hardens on exposure to the air. But it not only spreads over the surface of the wound, it penetrates also to the interior of the wood, fills the cell- cavities, and saturates the cell-walls. According to their direction, the resin-canals of the wood and bark of conifers may be classified into horizontal and vertical; the former are found especially in the medullary rays. Briefly, the object attained by conifers in sacrificing so large a quantity of food-material in the production of resinous secretions, is the acquisition of a substance which furnishes a complete remedy against a great variety of injuries to which the woody tissues are subject. The author then investigates the functions of similar secretions formed by other orders of plants, especially that of resinous sub- stances, gums, and latex. The entire absence of substances of this nature in large groups of plants, as the Palme, Cyperacez, Graminex, and the greater number of Crucifere and Ranunculacee, indicates that their function must have relation to special circumstances. That the function of all these substances is similar is further indicated by the fact that they replace one another in different plants or groups of plants, it being very unusual to find more than one kind in the same species. Again, under normal conditions, they are never resorbed out of their reservoirs to take part in other nutritive processes; as long as they remain in their reservoir they are completely inactive. In this situation they are always subject to a certain pressure which * Arch, Néerland. Sci., xvii. (1882) pp. 59-82. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 821 causes them to flow over the surface of the wound when the reservoir is injured. All the substances produced by the hardening of latex and the other resinous fluids in contact with the air, resin, caoutchoue, wax, &c., are glutinous, and are admirably adapted for the protection and healing of wounds. On escaping from their receptacle they are decomposed into two parts, a thin liquid fluid, and the thick mucila- ginous substance which was previously dissolved in the first. Their function, in fact, appears to be identical with that of the resin and terebenthin of conifers. One of the injurious results of wounds which they prevent is the settlement and germination in the exposed tissue of the wounded part of the spores of parasitic fungi. In plants and organs of the simplest structure, such as Thallo- phytes, mosses, and the prothallia of ferns, the process of recuperation after a wound is simply that the injured cells die and are not replaced, the uninjured cells in contact with them carrying on the life of the individual. In plants of higher organization, on the contrary, the injured tissue must be replaced by a freshly formed tissue, which process is carried on under the protection of these resinous secretions. This new tissue is of the nature either of callus or of traumatic bark, both resulting from the segmentation of cells by cell-walls parallel to the surface, new layers being formed in this way, the walls of whose cells are subsequently impregnated with suberous matter. Change of Starch into Sugar at low temperatures.*—H. Miiller- Thurgau has experimented on the sweetening of potatoes by frost, depending on the conversion of starch into sugar. He finds that it depends on the freezing taking place slowly, and on the temperature sinking to at least — 3° C. When once begun the process goes on rapidly. Different kinds of potatoes exhibit very different properties in this respect, and the presence of a large amount of water promotes the sweetening. The transformation is occasioned by a diastatic ferment, the propagation of which is promoted by a low temperature. Colours of Flowers.t{—In an article by Grant Allen, on “The Colours of Flowers, as illustrated in the British Flora,” the author says that the different hues assumed by petals are all, as it were, laid up beforehand in the tissues of the plant, ready to be brought out at a moment’s notice. And all flowers, as we know, easily sport a little in colour. But the question is, Do their changes tend to follow any regular and definite order? Is there any reason to believe that the modification runs from any one colour towards any other? Apparently, there is. All flowers, it would seem, were in their earliest form yellow; then some of them became white; after that, a few of them grew to be red or purple; and, finally, a comparatively small number acquired various shades of lilac, mauve, violet, or blue. Some hints of progressive law in the direction of the colour- change from yellow to blue are sometimes afforded us even by the * Naturforscher, xv. (1882) pp. 349-51. y Allen, Grant, ‘The Colours of Flowers as illustrated in the British Flora.’ 119 pp. (8vo, London, 1882.) Cf. Bull. Torrey Bot. Club, ix. (1882) pp. 117-8. 822 SUMMARY OF CURRENT RESEARCHES RELATING TO successive stages of a single flower. For example, one of our common little English forget-me-nots, Myosotis versicolor, is pale yellow when it first opens; but as it grows older, it becomes faintly pinkish, and ends by being blue, like the others of its race. Now, this sort of colour-change is by no means uncommon; and in almost all known cases it is always in the same direction, from yellow or white, through pink, orange, or red, to purple or blue. Thus one of the wall-flowers, Cheiranthus chameleo, has at first a whitish flower, then a citron- yellow, and finally emerges into red or violet. The petals of Stylidium fruticosum are pale yellow to begin with, and afterwards become light rose-coloured. An evening primrose, Cinothera tetraptera, has white flowers in its first stage, and red ones ata later period of develop- ment. Cobea scandens goes from white to violet; Hibiscus mutabilis from white, throngh flesh-coloured, to red. The common Virginia stock of our gardens (Malcolmia) often opens of a pale yellowish green, then becomes faintly pink, afterwards deepens into bright red, and fades away at last into mauve or blue. Fritz Miller noticed in South America a Lantana, which is yellow on its first day, orange on the second, and purple on the third. The whole family of Boraginacece begin by being pink, and end by being blue. In all these, and many other cases, the general direction of the changes is the same. The are usually set down as due to varying degrees of oxidation in the pigmentary matter. . _ If this be so, there is a good reason why bees should be specially fond of blue, and why blue flowers should be specially adapted for fertilization by their aid; for bees and butterflies are the most highly adapted of all insects to honey-seeking and flower-feeding. They have themselves, on their side, undergone the largest amount of specialization for that particular function. And if the more specialized and modified flowers, which gradually fitted their forms and the posi- tion of their honey-glands to the forms of the bees or butterflies, showed a natural tendency to pass from yellow, through pink and red, to purple and blue, it would follow that the insects which were being evolved side by side with them, and which were aiding at the same time in their evolution, would grow to recognize these developed colours as the visible symbols of those flowers from which they could obtain the largest amount of honey with the least possible trouble. Thus it would finally result that the ordinary unspecialized flowers, which depended upon small insect riff-raff, would be mostly left yellow or white; those which appealed to rather higher insects would become pink or red; and those which laid themselves out for bees and butter- flies would grow for the most part to be purple or blue. Now, this is very much what we actually find to be the case in nature. Causes of the Etiolation of Plants.*—E. Mer points out that the aquatic forms of amphibious plants present, in their external appearance and internal structure, a close analogy with the forms of aerial plants grown in the dark or in moist air. A comparison of these phenomena shows that etiolation is the result of a variety of * Comptes Rendus, xev. (1882) pp. 487-9. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 823 causes of different importance acting together or separately. When the stem is rudimentary or reduced to a bulb, and the leaves are sessile, the nutritive equilibrium exercises only a feeble influence, since the nutritive materials are all collected in one organ; the relative dimensions only of this organ are modified. The most complex case is where the causes of etiolation combine, as when an aquatic plant, furnished with a stem and petiolate leaves, is immersed in the dark, as occurs in the first leaves of water-plants growing at a great depth. Origin of Galls.*—JIn opposition to the view of Dr. Adler, J. Paszlavszky has established that all rose-galls arise in leaf-buds which have been punctured by Rhodites rose. The female works in three directions corresponding to the phyllotaxis of the rose, laying her eggs, which are provided with a long stalk, on the three leaves which constitute a whorl.t All galls become in this way circular by the shortening of the internodes. All terminal galls are originally circular, and have become terminal by the gradual withering of the leaves from the apex downwards. The ultimate form of the gall depends greatly on the number of larve that develope within it. B. CRYPTOGAMIA. Muscinee. Male Fructification of Polytrichum.t—K. Goebel investigates the phenomena connected with the habitual prolification of the antheridial receptacle or male fructification of Polytrichum. He finds that Leitgeb’s rule, derived from the case of Fontinalis, that the first antheridium springs from the apical cell, and is the termination of the primary axis, is not of general application. In Polytrichum, on the contrary, the large apical cell of the primary axis may be recognized in the middle of the fructification; the first antheridium cannot therefore proceed from it. From each leaf- forming segment beneath the leaf springs a group of antheridia. It follows from this that the antheridia which form a group do not stand at the same height, but are arranged in two or three superposed rows. Among them stand a great number of densely packed para- physes, which, together with the somewhat modified leaves, completely enclose the antheridia. A leaf is produced of each segment of the apical cell. The growing point of the stem is not, as in Fon- tinalis and other genera, slender, but flattened, somewhat as in Lyco- podium Selago. Ata later period, when the antheridia are mature, the growing point even les in a cup-shaped depression. The flattening of the growing point is caused by the growth of each segment being stronger in its upper portion nearest the surface of the stem than in its lower part. From the base of the young leaves hairs spring at an early period on the side which faces the apical cell ; antheridia have never been observed in this position. * Naturforscher, xv. (1882) p. 308. + The phyllotaxis of the rose is 2-5, five leaves making up two whorls.— ; a Flora, Ixv. (1882) pp. 823-6 (1 pl.). 824 SUMMARY OF CURRENT RESEARCHES RELATING TO The development of the separate antheridia agrees with that of Fontinalis ; they have a 2-edged apical cell, which produces two rows of segments. The youngest stage shows two inner cells surrounded by a number of parietal cells. The further arrangement of the cells in subsequent divisions probably differs in different genera. It follows from what has been said, that in Polytrichum, the antheridia do not, as is generally stated, stand in the axils of the leaves, and that their arrangement differs from what has been pre- viously observed. While in Fontinalis and other genera of mosses, the antheridia differ in their place of origin, the first springing from the apical cell, the next in place of the leaves, the subsequent ones having no definite point of origin, in Polytrichum all the antheridia have the same origin, viz. beneath the leaves from outer cells of the tissue of the stem which belong to the same segment as the leaf. This fact furnishes another illustration of the general law that the place of origin of an organ does not determine its morpho- logical value. Fungi. Epiplasm of Ascomycetes—Glycogen of Plants.*—The following are the principal conclusions of Dr. L. Errera on this subject, the method adopted for extracting glycogen from fungi and other plants being that of Briicke,j slightly modified in some cases. 1. Glycogen or “animal starch” exists not only amongst the animals in which Claude Bernard discovered it, and in the Protista (where it was first pointed out by Kiihne), but is also found in lants. i 2. Many of the ascomycetous fungi contain it in their tissues and in their asci. Pilobolus, and, almost certainly, the yeast of beer, equally contain it. The identity of the glycogen of Peziza vesiculosa (which the author has studied most in detail) with the glycogen of the liver of Mammalia is complete. 3. The epiplasm of the asci of Ascomycetes, suspected by Tulasne and described by de Bary, is formed of a spongy mass, probably albu- minous, completely permeated with glycogen. 4, Even outside the fungi, all the plants studied (Lemanea, Linum, Mahonia, Solanum) contain substances at least analogous to glycogen, non-nitrogenous, giving more or less opalescent aqueous solutions which turn more or less brown with iodine, having no reducing action whatever on the cupro-alkaline reagents, but becoming transformed into reducing bodies by boiling with dilute sulphuric acid. 5. There also exist reducing substances analogous to the dextrines in the aqueous extracts of several plants (Tuber, Agaricus, Solanum) ; in others they have not been found (Peziza, Lemanea). 6. When it is not in too small a quantity the glycogen may be * Errera, L., ‘L’Epiplasme des Ascomycetes et le Glycogene des Végétaux.’ 81 pp. (8vo, Bruxelles, 1882). + SB. K.K. Akad. Wiss. (Wien), lxiii. (1881) p. 214; and Vorles. tiber Physiol., i. (1881) p. 324. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 825 determined by microchemical means, by its appearance, by its semi- fluid consistency, by the absence of reaction with osmic acid, Millon’s reagent, and the salts of iron, by its solubility in water, and by its assuming with iodine a mahogany-brown or brown-red colour, which dissipates with heat and reappears on cooling. The proteid substances, on the contrary, become yellow rather than brown with iodine, and this colour is not diminished by moderate heating. 7. The glycogen of the Ascomycetes, at first diffused throughout the whole of the young plant, as it is in the animal kingdom in the foetus, soon accumulates in the asci in considerable quantity, and disappears gradually as the spores ripen. 8. It is utilized in the development of the spores. Besides its eventual function of a respiratory reserve, there are good reasons for supposing that in the truffles, and probably also in other Ascomy- cetes, it furnishes materials for the formation of the oil of the ripe spores. 9. Around glycogen and starch are ranged some allied substances. It is thus that we are led to place in contact to one another a glycogen group and a starch group. We may, with Boehm and Hoffmann, rank with the former the glycogen of the liver and that of the muscles, xantho-glycogen, achro-glycogen, and glycogen-dextrin ; and among the latter, starch, the amylo-dextrins, and inulin. 10. Glycogen, glycogen-dextrin, starch, amylo-dextrin, and inulin do not give true solutions with water ; they only forma kind of magma, more or less thin, in which the greater portion of the substance is mechanically suspended. This fact helps us to understand the storing up of glycogen and inulin in particular cells. Agaricini.*—In a review of our present state of knowledge of the Agaricini, 8. Schulzer holds that the generic classification of Agaricus according to the colour of the spores, though not a natural classification, is the most convenient at present proposed. The division into subgenera is not so satisfactory ; and he adduces several instances in which a series of forms belonging to the same species must be placed some in one and some in another subgenus. With regard to the genera of Agaricini outside Agaricus, he con- siders that there is no sufficient distinction between Cantharellus and Craterellus, nor between Panus and Lentinus. Marasmius also should be united with Agaricus. Development of Sclerotium of Peziza Sclerotiorum.t—Correct- ing some mistakes in the account previously given by Brefeld and Coemans, O. Mattirolo gives the following description of the mode in which the cup of Peziza Sclerotiorum is formed out of the sclero- tium :— The sclerotium varies greatly in form; but a cortical layer from two to four cells in thickness can always be distinguished from the medullary portion. The first rudiments of the cup make their appear- ance in the outer medullary layers. The hyphe divide and become * Oesterr. Bot. Zeitschr., xxxii. (1882) pp. 186-9, 220-5, 250-3. t+ Nuov. Giorn. Bot. Ital., xiv. (1882) pp. 200-12 (2 pls.). 826 SUMMARY OF CURRENT RESEARCHES RELATING TO closely entangled, but without an ascogonium being distinguishable ; a small endogenous ball of slender hyphe being thus formed, which continues to increase in size, and finally bursts through the cortical layers which have bulged out into a spherical form. From this ball a string of hyphe grows upwards, surrounded by a cylinder of thicker hyphe derived from the detached outer medullary layers of the sclero- tium. These outer coarser hyphe form the cortical layer of the cup, the inner bundle developes into the medullary layer of the stalk, and later into the hymenium. The body thus formed is at first cylin- drical; the cortical hyphe diverge at their distal end, and thus form a club-shaped structure; while the finer central hyphe converge distally. In the middle of the bundle the hyphe cease after a time to increase in length; while the outer ones continue to grow, and thus form an elongated cylinder. The wall of this canal is clothed with the ascogenous ends of the hyphe. At a later period the canal becomes wider above, becoming first funnel-shaped and the margin then expanding flat, thus forming the well-known cups of Peziza Fuckeliana. At first paraphyses only are visible on the disk; the asci are first formed in the centre, and gradually extend to the margin. Usually several are formed on the thickened end of each hypha ; but the ascogenous hyphe appear to have the same origin as the sterile ones which become paraphyses. Development of the Sporangia of the Phycomycetes. *—M. Biisgen describes the mode of development of the sporangia and of their zoo- spores in the following genera of Phycomycetes :— Dictyuchus, Lepto- mitus, Saprolegnia, Achlya, Aphanomyces, Phytophthora, Cystopus, Pythium, Peronospora, and Mucor. These exhibited several distinct modes of spore-formation. In some cases a number of spores are developed within the sporangium to more or less complete isolation. In these cases cell-plates are formed, the entire contents of the sporangium dividing, but not always simultaneously, into nearly equal portions. -The cell-plates then partially or entirely deliquesce into a hyaline mass, finally disappear- ing altogether. At the same time the structure of the protoplasm contained in the sporangium changes; it becomes more uniformly granular and transparent, a large number of small round vacuoles appearing at the same time. These partially disappear, and fresh cell-plates are again formed. Each of the portions of protoplasm separated by them contains one of the small vacuoles, and is the protoplasm of the subsequent spores. The cell-plates either form the cellulose-membranes of the spores or pass over into intercellular substance. In Aphanomyces there are, however, no cell-plates ; and the mode of formation of the intercellular substance presents a difficulty, It may be produced in the way described by Strasburger in the case of some swarm-spores, or it may be regarded, with de Bary, as a secretion from the mature spores. An analogous production of temporary cell-plates has been * Pringsheim’s Jahrb. f. wiss. Bot., xiii, (1882) pp. 253-85 (1 pl.). ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 827 observed by Strasburger in the formation of the pollen of some phanerogams and of the spores of some vascular cryptogams, and in the formation of the endosperm in the embryo-sac. The mode of formation of the zoospores of Phytophthora agrees with that already described in the Saprolegnier. In Pythiwm the formation of cell-plates is in most cases very doubtful. The question of the presence or absence of the cell-nucleus in the sporangia presents many difficulties. In some cases round or len- ticular bodies exhibiting the reaction of nuclein can be made out with certainty. In Leptomitus it is especially distinct, each spore possess- ing one nucleus. In other cases each spore contained two nuclei; while in others the presence of a nucleus could not be certainly demonstrated. The processes which take place in the formation of the zoospores within the sporangia of the Phycomycetes must be regarded as falling within Strasburger’s definition of true cell-division. Alternation of Generations in the Hypodermie.*—M. Cornu has been able to produce the aecidium of Puccinia arundinacea on Ranun- culus repens from spores, but not abundantly, and always late in the year, viz. in October and November. This species does not attack R. bulbosus, acer, sceleratus, or Flammula, or Lonicera. Ranunculus acer, bulbosus, and repens are, however, also subject to the attacks of an aecidium derived from Uromyces graminum Cooke; the ranuncu- laceous plants Aquilegia vulgaris, Acteea spicata, Aconitum Napellus, and Hepatica triloba support aecidia which are considered to be distinct from the above. The puccinia-form of P. arundinacea occurs on Arundo Phragmites ; thus the species inhabits plants of very different characters at different stages of its life-history. ‘*Mal Nero” of the Vine.,—O. Comes has determined that this widespread disease is caused by a production of gum like that to which stone-fruit trees are liable, the result of insufficient nutrition ; and that the fungi which always accompany it are a secondary phe- nomenon only. The best cure is copious manuring, and especially the abundant supply of-phosphates and lime-salts. Aubernage: a Disease of the Vine.t—For some time past a disease of the vine called “* Aubernage”’ has shown itself at Auxerre in the department of Yonne, with most disastrous results, After first small and then large spots have appeared on the branches, a rapid disorganization of the tissue of the wood commences, which, beginning at the extremities of the branches, spreads downwards to the roots and completely destroys the plant. C. Roumeguére has proved the existence of three fungi in the diseased branches. Phoma vitis Bk. & B., Phoma pleurospora Sacc. var. forma vitigena, and Sphaerella pampini Thm., and believes that in the joint action of these fungi he has dis- covered the true cause of the disease. * Comptes Rendus, xciv. (1882) pp. 1731-4. + L’Agricolt. merid. Portici, v. (1882) pp. 64-72. See Bot. Centralbl., xi. (1882) p. 97. Cr. this Journal, ante p. 229. } Revue Mycol., iv. (1882) pp. 1-3. See Bot. Centralbl., xi. (1882) p. 98. 828 SUMMARY OF CURRENT RESEARCHES RELATING TO Parasites of the Saprolegniez.*—A. Fischer has made a detailed examination of the group of minute fungi parasitic on the Sapro- legniew, which were at one time taken for the reproductive organs of their hosts, the organisms themselves for antheridia, their zoo- spores for spermatozoids. They comprise the three genera Olpidiopsis Cornu, parasitic on Saprolegnia feraxz, Rozella on S. dioica, and Woronina on Achlya dioica. The mode of observing them adopted was to cultivate the Saprolegnia, &c., on larve of ephemerides, which became completely covered with the fungus in twenty-four hours, the parasite always attacking the latter after the course of a few days. ae: a general description, applying to the whole group, of the structure and movement of the zoospores, and the mode in which the parasite penetrates the host, in extension of previous observations on the same points,t the author proceeds to a separate description of each genus. Olpidiopsis is distinguished by its nearly spherical or shortly elliptical sporangia with smooth surface, which are found in swollen and deformed Saprolegnia-sacs. In addition to the ordinary zoospores, there occur also spined sporangia of the same size as the smooth sporangia, which perform the function of resting spores in the cycle of development of Olpidiopsis. The smooth spineless sporangia are developed both from the spores of the spineless and from those of the spined sporangia under favourable circumstances, a single sporangium only springing from each spore. ‘The view of Cornu and others, that the spined sporangia are organs of a sexual nature, rests on inaccurate observation. The number of species of Olpidiopsis is probably much larger than has yet been described, the parasites of Cosmarium and other desmids probably belonging to this genus. Rozella forms a number of closely packed sporangia in uninjured Saprolegnia-filaments. The wall of its sporangium is inseparable from that of its host. Like the last genus, it forms also spined sporangia. Each spore which penetrates the host developes within it a large number of sporangia, the spore appearing to lose -its individuality, and its protoplasm to become intimately mingled with that of the host. The same is the case with the spores from the spined resting sporangia. This applies to the section of the genus described by Cornu, and which may be termed the septigena-group ; in another section the spore-forming organs are solitary. Woronina is characterized by the formation of a sorus. The fila- ment is divided by septa, and in each chamber is developed a sorus consisting of a larger or smaller number of sporangia. Hach spore of the sporangial sorus gives birth again to a sorus, one generally spring- ing from each spore. The author was not able to confirm the state- ment of Cornu that this genus produces also resting spined sporangia ; the resting condition appeared, on the other hand, to consist of the accumulation into cysts of a large number of sori, forming what may be termed “cystosores,” bodies resembling in external appearance * Pyinesheim’s Jahrb. f. wiss. Bot., xiii. (1882) pp. 286-371 (3 pls.). g Pp + See this Journal, i. (1881) p. 87. — ZOOLOGY AND BOTANY, MIOROSCOPY, ETC. 829 the cystoliths of Urticacee, Only a single species has as yet been observed, parasitic exclusively on Saprolegnia. In all stages of development of all three genera cell-nuclei have been observed. Each zoospore, on escaping, contains a nucleus. No sexual reproduction takes place in any of them. Fischer gives the following as the distinguishing characters of the three genera :— 1. Olpidiopsis. The single spore developes as an individual directly into a sporangium. 2. Woronina. The single spore becomes enclosed as an individual in a soral chamber; it then loses its individuality, and transforms the entire contents of the chamber into a soral plasmodium. From each spore is developed a single sorus. 3. Rozella. The separate spores lose their individuality im- mediately after penetrating the host, and mingle their protoplasm with that of the host. In each division of the filament there is not therefore a plasmodium sprung from an entire spore, but only a part of one; the plasmodium resulting from a spore fills the entire filament. From each spore proceeds a row of sporangia. Olpidiopsis is the simplest form of the group, Rozella occupying the highest position, and the three genera are genetically connected as different stages of development. The life-history may be divided into two periods ; in the vegetative period it is a naked mass of proto- plasm, spontaneously changing its form, a plasmodium; the repro- ductive period is characterized by the separation of zoospore-producing organs. The author considers that these three genera must form a group by themselves distinct from the Chytridiaceze, which are characterized by a more or less developed mycelium and by a process of sexual re- production. Diastatic Ferment of Bacteria.*—J. Wortmann considers that the reason why bacteria do not, in the ordinary way, attack starch-grains, is that the starch is usually accompanied by albuminoid and other substances, from which the bacteria obtain their food-materials more readily. In order to determine the power of bacteria to decompose starch, this substance must be presented to them in a state of purity. Experiments in this direction yielded the following results :— 1. Bacteria have the power of producing in starch-grains, starch- paste, and dissolved starch the same changes as are caused by diastase. 2. Different kinds of starch are dissolved with different degrees of rapidity by bacteria, as by diastase. 3. The bacteria exercise this influence on starch only when no other serviceable carbon-compound is available, and when the access of air is not in any way impeded. Thus if only the slightest trace of tartaric acid is present in the fluid, the starch is not attacked ; but when this disappears, the starch at once begins to dissolve. 4, The action of bacteria on starch is brought about by a ferment ty ana fir physiol. Chimie, vi. p. 287. See Naturforscher, xv. (1882) ae ox 830 SUMMARY OF CURRENT RESEARCHES RELATING TO which they excrete for this purpose, and which, like diastase, is soluble in water and precipitated by alkalies. 5. This ferment acts only diastatically, and does not peptonize ; i. e. it transforms starch into a sugar which reduces copper-oxide. 6. The ferment itself can act cn starch even in the absence of oxygen. 7. The ferment is excreted by the bacteria even in neutral | solutions containing starch; and under these conditions without action. 8. The action of the ferment is accelerated in slightly acid solu- tions. From these results Wortmann deduces the theory that bacteria produce a ferment which peptonizes albumen, but which has only a diastatic action on starch in the absence of albumen and other sources of carbon. Bacteria of Intermittent Fever.*—A. Rézsahegyi confirms the observations of Klebs and Tommasi-Crudelif with regard to the efficiency of filamentous bacteria in acting as carriers of the contagion of malarial fever. Placing a small quantity of the marshy soil of a malarial district of Hungary in a drop of solution of isinglass, he allowed this to stand in a warm place, when the malarial bacilli shortly made their appearance. When mixed with pure isinglass, the culture invariably succeeded at once ; but if from one of these cultures a drop is taken containing abundance of bacilli and spores, and again placed in pure isinglass, this secondary culture succeeded only in about one-third of the cases. This is attributed by Rdozsahegyi to the fact that, in addition to organic matters, the bacillus requires mineral constituents for its nutrition. For the secondary culture, heating to 50°-100° C. reduced the germinating power of the bacillus by about 2 per cent.; while a temperature between zero and 20-6° raised it by 50 per cent. Moist heat hence diminishes the germina- ting power, while moist cold increases it. The resting spores were killed only by an exposure for two hours to a temperature of 190°- 195°. Bacterial Parasite of the Chinch Bug.t—In the course of some experiments upon the chinch bug, 8S. A. Forbes was annoyed by their rapid disappearance, and, crushing some, examined their fluids under the Microscope. In every case these were found to be swarming with a species of Bacterium not easily distinguishable from B. termo. The observations were many times repeated with every precaution against accidental infection, but with the same results. Careful search in the juices of the corn upon which the insects were feeding, failed to discover anything of the kind there, and if a bug were thoroughly washed in a drop of distilled water no bacteria occurred in the water, showing that they were not derived from the surface of the insect. When a number were kept for a week in a * Biol. Centralbl., ii. (1882). See Naturforscher, xv. (1882) p. 196. + See this Journal, i (1881) p. 287. t Amer. Natural., xvi. (1882) pp. 824-5. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 831 bottle without food, the bacteria were found to have greatly increased in numbers, and were especially abundant in those which were recently dead. Dissections were made for the purpose of ascertaining whether the seeming parasites could be traced to the alimentary canal and in five cases the digestive organs were isolated and crushed. In all these cases the bacteria were very abundant, and could be seen issuing from the stomach in adherent masses, and also in motion separately in all parts of the field. In two cases where a comparison could be made between the contents of the anterior and posterior parts of the canal, they were found much the most numerous in that part of the canal posterior to the Malpighian tubes. The author therefore con- cludes that they have their principal, perhaps exclusive, seat in the alimentary canal. Similar experiments made upon chinch bugs taken from the field, gave similar results throughout; but nothing of the sort could be detected in the fluids of the corn-plant louse (Aphis maidis) feeding upon the same stalks, nor in any of a number of insects examined. Etiology of Distemper.*—Dr. R. Koch has collected together the literature which records the experiments that have been hitherto made respecting the cause of the distemper (Milzbrand) of cattle, and attempts to settle various disputed points connected with it. Koch considers that a frequent source of error in the recorded results is the existence of other infectious complaints, as for example, septicemia, which present a strong similarity to the distemper, and which are caused by similar bacilli. No certain method of dis- tinguishing these various bacilli has yet been indicated. In opposi- tion to the view of Pasteur that the disease always results from injury to the digestive organs, Koch maintains that infection may be carried from the intestines to other parts of the body when in a normal condition. Buchner’s statement ¢ that the bacilli of hay and of distemper can be mutually transformed one into the other, he also regards as resting on insufficient evidence, the requisite care not having been taken to exclude the possibility of the entrance of foreign bacteria into the culture. His own experiments showed that the distemper-bacilli could go through a very large number of genera- tions unchanged, and still retain as great virulence as if they had been just removed from infected blood. The author regards Pasteur’s assertion, that “the etiology of distemper has been discovered, and with it the prophylaxis of this disease” as premature, many questions regarding it being still undecided. In conclusion, he discusses the question whether the bacilli of this disease can go through their course of development independently of the animal organism. He considers the evidence to be in favour of the conclusion that distemper makes its appearance in localities where dead bodies affected with it have never been buried, and where there is no reason to suppose that infected animals can * Koch, R., “Zur Aetiologie des Milzbrandes,” Struck’s Mittheil. aus d. K. Gesundheitsamte, i. (1881). See Bot. Centralbl., x. (1882) p. 289. ¢ See this Journal, ante, pp. 89, 382. 3K 2 832 SUMMARY OF CURRENT RESEARCHES RELATING TO have brought it. He considers that it can be clearly established that these bacilli can produce spores and go through all stages of develop- ment without coming into contact with any animal substance ; pro- pagating themselves extensively on vegetable substrata in moist situations during the warm months; the spores retaining their power of vitality through the winter. Experimental Production of the Bacteria of Distemper.*—H. Buchner has experimented on the methods by which the infectious fungus of distemper can be artifically transformed into the harmless hay-bacterium. Of the latter he considers the correct name to be Bacterium subtile. The transformation is effected by means of a con- trivance which is described in detail, by subjecting the infectious fungus to the influence of abundant supply of food-material and abundant oxygen. From the true distemper-bacteria, with clear nutrient fluid and delicate white clouds at the bottom, three transi- tion-stages are thus obtained, viz.— 1. Nutrient fluid clear or clouded with flecks; a white rim formed where the surface of the fluid touches the glass; white flecks at the bottom of the fluid. 9. Fluid clouded with flecks; very loose pellicle with a mucila- ginous appearance, which sinks to the bottom with the least shaking ; bottom covered with flecks and fragments of the pellicle. 3. Fluid clear or clouded with flecks; pellicle consistent, but with a mucilaginous appearance ; no flecks at the bottom. These lead to the true hay-bacteria; when these only are present, the nutrient fluid is completely clear, and there is a dry, firm, white pellicle often finely wrinkled, with a pulverulent appearance, and easily submerged. Germs of Malaria.t—In continuation of the researches of Tommasi- Crudeli and Klebs,f A. Ceci has further investigated the conditions under which malarial germs germinate in the soil. He concludes that in the atmospheric air and in the soil there are usually only germs or spores, which can develope under certain favourable condi- tions into more highly organized forms. This development almost invariably causes, in the fluids and moist substances in which it takes place, certain chemical changes, which are collectively known as fermentation. When the development takes place in nitrogenous or albuminoid substanees, the highest kind of fermentation or putrefac- tion ensues. ‘The effect of heat upon the germs is to retard their development, and consequently the fermentation or putrefaction. The fermentation produced by the germs in animal organisms, or fever, is retarded by the same agencies. The development of the germs may take place without causing fermentation, and is then apparently harmless. The succession of generations of the organisms which occurs * SB. K. Bayer. Akad. Wiss. Miinchen, 1882, pp. 147-69. See Bot. Centralbl., xi. (1882) p. 239. Cf. this J ournal, ante, p. 89. + Arch. f. experim. Path. u. Pharmak., xv. p. 153, and xvi. p. 1. See Natur- orscher, xv. (1882) p. 332. ~ See this Journal, i. (1881) p. 287. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 833 under artificial conditions hinders the putrefaction which the lower organisms occasion in nitrogenous fluids, and may even entirely stop it. This appears to the author to account for the gradual subsidence and ultimate complete disappearance of fevers and other ferment diseases caused by them. In malaria, these organisms appear to lose their infectious properties very rapidly, and thus become incapable of conveying the malady from one infected animal nidus to another. Under favourable conditions they may however return to the con- dition of natural germs, and become once more infectious. In this way malaria may be conveyed by human subjects from an infected district to one previously free. The rapidity with which this re- version of the germs to their natural condition takes place may be the cause of the extreme contagiousness of such diseases as the distemper of cattle. Prevention of Fermentation by Vegetable Acids,*—M. Marcken gives the following as the proportions of various acids which prevent a solution of sugar from fermenting :—acetic acid 0-5 per cent. ; formic acid 0*2, propionic acid 0-1, butyric acid 0-05 (or completely when 0-1 per cent. is present), and a mere trace of capronicacid. A propor- tion of 0°6 per cent. of acetic or 0°05 per cent. of butyric acid in a nutrient fluid prevents the increase of yeast; while as much as 3:5 per cent. of lactic acid is required for the same purpose. Fermentation of Maize-starch.{—V. Marcano has investigated the process of fermentation in “chicha,” an alcoholic liquid pre- pared by the American Indians from maize-grains. He states the fermentation to be due to the reproduction of a very characteristic organism, which has three forms of development, as a vibrio, as nucleated torula-like globules, and as myceloid tubes, from which, at a certain period, vibrios escape, the membrane which forms the septa of the filament being at the same time resorbed. It is found in the exterior pellicle of maize-grains, and can be transformed from one form into another by culture in different nutrient fluids. The ferment of chicha is further characterized by the property of acting directly on young starch, such as that contained in the embryo of maize-grains; the products of decomposition being dextrin, alcohol, and carbonic acid gas. The starch-grains on which it has acted are reduced to the condition of flakes of cellulose-starch (farinose), all the granulose having disappeared. The organism resists the action of boiling water at 95° C. con- tinued for some minutes; the most favourable temperature for its production being 40°-45°. It can also ferment milk-sugar, saccharose, and glucose. During the germination of maize, the vibrios develope in the interior of the grain in vast numbers. They have also been detected in the stem, immediately beneath the bark, and in the leaves. The facts here recorded are considered by the author to explain the * Zeitschr. f, Spiritusindustrie, iv. (1881) p. 114. See Bot. Centralbl., xi. (1882) p. 299. + Comptes Rendus, xcy. (1882) pp. 345-7. 834 SUMMARY OF CURRENT RESEARCHES RELATING TO phenomenon of the resorption of starch-grains; and of the rise of temperature which takes place during germination ; as also the pro- duction of other substances, hitherto unexplained, in the elaborated sap. Fermentation of Nitrates.*—The researches of MM. Schloesing and Muntz have proved that nitrification, in the ground and in organic liquids, is due to development of small organisms (corpuscules brillants of Pasteur).| MM. Gayon and Dupetit having been led to think that the opposite process, viz. reduction of nitrates, is also a physiological phenomenon, have investigated the matter experiment- ally, and found a microbe which attacks nitrates in presence of organic matters (e. g. sewage water containing a little nitrate of potash with some altered urine, or preferably, chicken-broth) which cause the products of fermentation of the nitrate to enter into new combinations. Pure nitrogen is liberated, representing a large proportion of that of the nitrate, the rest forming ammonia, and perhaps amidized deriva- tives of the organic matter, the liquid being filled with the microbes. Carbolic acid and salicylic acid, in antiseptic, or even larger doses, not only do not hinder the life of the reducing microbe, but them- selves disappear completely with the nitrate, in the same way as sugar or propylic alcohol. Alge. Composition of Fucus amylaceus.[—The chemical analysis of the alga Spheerococcus lichenoides Ag., known as Fucus amylaceus, has yielded the seven following carbo-hydrates :— 1. A mucilage soluble in water. The drug extracted with cold water yields a small quantity of mucilage which is precipitated in alcohol, and is converted into sugar by acids. Mannite and grape- sugar are wanting in the aqueous solution. 2. A gelatinous non-nitrogenous substance, with ash amounting to 4-43 per cent.; the analysis yielding C 45-55, H 5-99 per cent., nearly corresponding to the formula 4 (C,H,0; — H,O). Seven parts in bulk of alcohol produce a precipitate in the hot solution; its solubility in cupric oxide distinguishes it from the lichenin extracted by Berg from Cetraria islandica ; iodine and H,SO, do not colour it blue; hence it is not a soluble modification of cellulose. This gelatinous substance must not be confounded with the pararabin discovered by Porumbaru in the Japanese Agar Agar. The aqueous solution of the foregoing turns the plane of polarization to the left, and is extremely opalescent. 3. Starch-flour. 4, A pararabin-like substance. The residue of the Fucus was macerated in one per cent. muriatic acid, pressed out, filtered, and the product precipitated with alcohol. The purified precipitate is a white powder containing sulphate of lime. The substance freed from ashes shows the following composition: C 44°78, H 5:95 * Comptes Rendus, xcv. (1882) pp. 644-6. + Cf. this Journal, iii. (1880) p. 314. + SB. Naturforsch. Ges. Dorpat, vi. (1881) pp. 39-48. See Bot. Centralbl., xi, (1882) pp. 5-6. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 835 per cent., which nearly corresponds to the formula C;H,,0O;, and therefore closely resembles Reichardt’s pararabin, but differs in this, that when boiled with a diluted inorganic acid it yields sugar. 5. Metarabin. After a second extraction with dilute hydrochloric acid, the alga being saturated with dilute caustic soda, the filtered solution precipitated with alcohol, and the precipitate purified, its reaction indicates metarabin. 6. Wood-gum. Obtained from the residue by the addition of 10 per cent. potash ley. Besides these was also obtained :— 7. Cellulose. All these substances boiled in dilute inorganic acids pass into sugar. Mazea, a new genus of Cryptophyceze,*—A fresh-water alga recently discovered in Brazil, belonging to the group of the Stigo- nemez, has been described by Drs. EH. Bornet and A. Grunow, under the name of Mazca rivularioides. This alga, remarkable in various ways, externally resembles Aivularia plicata Harv.; its fronds are rounded, more or less irregularly knobby, and attain to a diameter of about 25 mm.; at first solid and somewhat firm, they later become hollow and soft. The colour of moistened specimens is of a sombre green, inclining to olive. The trichomes, immersed in a homogeneous colourless jelly, spread themselves around a central space; they increase towards the periphery, and become lost in the interior. These trichomes give origin to branches, either scattered or unilateral, which elevate themselves to the same height, and to heterocysts either sessile on the side of the cells or borne on a pedicel of one to three cells ; intercalary heterocysts were not observed. The hetero- cysts are oblong in form, easily to be distinguished from the ordinary cells by their size, and above all, by the nature of their contents, which is more homogeneous; when old, they assume a yellowish tint; the chloriodide of zine colours them purple. When a cell forms a heterocyst or a branch, it first produces a lateral enlargement, which is very early separated. This new cell may at once change into a heterocyst, and then it will be directly applied to the side of the cell, as are the heterocysts of Capsosira and those on the large branches of Stigonema, or it may be divided once or twice before the formation of the heterocyst, which will be then pedicellated, or it may even form a cell from which a branch may arise. ‘lhe branches, like the heterocysts, are not uniformly arranged along the length of the filament. At certain spots they are closer and level. Some remain simple, others ramify, none terminate in a hair. No distinct trace of a sheath was observed around any of the younger portions of the trichomes, but at the base the cells are sometimes surrounded with a somewhat thick envelope. None of the specimens (not very numerous) examined showed the least trace of spores or homogonia. Two characters of this genus are particularly interesting, its rivulariaceous appearance, and its pedicellated heterocysts. This * Bull. Soc. Bot. France, xxviii. (1881) pp. 287-8 (1 pl.). 836 SUMMARY OF CURRENT RESEARCHES RELATING TO latter peculiarity, which hitherto has not been met with among the Cryptophyces, indicates in Mazea a degree of specialization of the parts of the trichome greater than that in any other genus of Stigonemaces, in fact it represents the highest develop- ment in the group. Now that in this genus and in Capsosira Brebissonii (= Stigonema zonotrichioides Nordst.), Stigonemacee have rivularioid representatives, it may be noted that Scytonemacez 1s the only tribe in which this type is wanting. Resting-spores of Conferva.*—Resting-spores have already been observed by a large number of inquirers in various Confervacez ; first of all in a Conferva first discoyered and figured by Itzigsohn, and de- scribed by him as Psichohormium uliginosum ; ‘and again, by Pringsheim, Famintzin, Cornu, and Rosenvinge, in the genera Ulothrix and Conferva ; and they are now found to be present in the whole genus Conferva (L.) Wille. N. Wille now adds to these contributions his observations on the manner of forming these resting-spores. In Oonferva Wittrockii n. sp. the spore-formation is thus carried on. The chlorophyllaceous contents contract and become rounded. ‘The colouring matter collects principally in the ends of the cells, so that the substance in the middle appears nearly colourless; but after the contraction of the cell-contents the chlorophyllaceous portions of the protoplasm draw nearer together, until at last they coalesce and form a round or elliptical body within the mother-cell; they then begin to surround themselves with a membrane, which later consists of two distinct layers. The spores are generally set free by the filaments resolving themselves into H-shaped cells (in which the cell-wall of each cell has a transverse fissure in the middle of the transverse walls); the spores then fall out. Sometimes they escape by the cell- walls becoming converted into mucilage, their layers becoming gradu- ally indistinguishable. On first germinating, the size of the spores increases, as the result of which the outer membrane bursts. ‘The outer membrane consists of two pieces with pointed ends, one being much larger than the other, and covering it like the lid of a box. Afterwards, through the expansion of the inner membrane, the smaller piece of the outer membrane gives way, and the inner membrane grows through the aperture thus formed in the form of a tube. The development was not followed further, but the writer considers it probable that zoospores are first formed from the resting-spores. The development in Conferva stagnorum Ktz. is of precisely the same character; but here the spores are mostly freed through the conversion into mucilage of the cell-walls. The germination proceeds either as in OC. Wittrockii, or transverse walls appear in the elon- gated resting-spores whose outer membrane is not burst, and the young filaments are thus formed. In germination, a sort of organ of attachment is formed by an excretion of mucilage in the pointed end of the spore ; or perhaps the mucilage is a local transformation of the outer membrane. In one case the author observed this sort of cell- * Ofversigt af Kong]. Vetensk.-Akad. Forhandl., xxxviii. (1881), 26 pp. (2 pls.). See Bot. Centralbl,, xi. (1882) p. 113, ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 837 division in various directions, and considers this phenomenon as the commencement of a palmella-condition. A third and new species, described as C. pachyderma, showed a special peculiarity of the vegetative cells. As a rule the author found imbedded in the transverse walls on each side of the cells, one, and sometimes two, crescent-like particles of cellulose sharply pointed on both sides, which were distinguished from the transverse walls by their more highly refringent power. When the cells are about to trans- form themselves into resting-spores, they increase somewhat in size, the chlorophyll augments and distributes itself uniformly, but no new membrane appears. It seems as if one, or, perhaps more strictly speaking, two new pointed box-like interlocked layers are formed in the inner, less watery, layer of the mother-cell-wall. The wall of the resting-spore is therefore the thickened wall of the mother-cell. The resting-spores escape through the conversion into mucilage of the outer part of the cell-wall. In germination a hood-shaped piece of the outer membrane of the resting-spore remains, which is attached to the basal cell. In Conferva bombycina Ag. var. minor, either single cells swell up into a barrel-shape, or here and there the contiguous ends of two neigh- bouring cells assume aclub-like form. It is here that the largest part of the chlorophyllaceous protoplasm accumulates, and after this the swollen end is separated by a transverse wall from the longer narrow part of the mother-cell. The wall of the swollen part thickens later. The author considers these cells to be resting-spores, although he was not able to observe their germination. C. bombycina Ag. var. genuina has similar resting-spores. We find accordingly that three modes of formation of the resting- spores of Confervacee have been observed, viz. (1) by rejuvenescence, and the formation of a new membrane round the contracting contents ; (2) by the thickening of the membrane of the mother-cell; (3) by separation of a portion of the cell-substance to a swollen part of the mother-cell, and the thickening of the membrane of this portion. Diatoms of the Baltic.*—H. Juhlin-Dannfelt has critically ex- amined the diatoms of the Baltic, describing over 300 species, including a number of new species and varieties. He finds them to belong entirely to brackish forms, except where fresh water has mixed with the salt, where many true fresh-water species occur. Comparing them with the forms found in the quaternary diatom-beds of Sweden, he finds no identical species, from which he infers a diminution in the amount of salt in the Baltic in historic times. Motion of Diatoms.—Colonel R. O’Hara writes: “As the subject of the movement of diatoms has been recently brought forward again, the following notes on the subject may be of interest :— In washing away the acid from diatomaceous material, I have * Bihang til R. Svenska Vet. Akad. Handlingar, vi. (1882) 52 pp. (4 pls.). See Bot. Centralbl., xi, (1882) p. 153. 838 SUMMARY OF CURRENT RESEARCHES RELATING TO constantly observed what appeared to be gelatinous casts of diatoms. In order not to lose these, I have been content to select diatoms from what would be called dirty strewed mixed slides. In the beginning of 1878, when watching diatoms in their living state, I observed what I thought was a Cocconeis moving freely, and there appeared to be an undu- Fig. 147. lating movement along the edge all round. On trying to isolate it I lost it under the cover. In December 1878 I came across what appeared to be a cast of a diatom (Stauroneis pulchella), of which I send two photographs* by direct and oblique light. The latter is for the purpose of showing the plasticity of the material more distinctly. It is represented by Fig. 147. The strive on three-fourths of the figure may be seen to be ' perfectly distinct and separate along the median line; they then generally coalesce or intertwine, separating again on nearing the edge of the membrane. In the remaining quarter the strie have ap- parently coalesced completely, and have formed with the membrane a continuous sur- face to the point, and beyond. If this be a cast, it strongly suggests movement by cilia or undulating membrane. It may be said that this is simply an imperfectly siliceous frustule. It must be remem- » bered, however, that the diatom in question had to go through the usual operations of washing, &c. Also why is only one-fourth acted upon up to the median line, whereas in the other three-fourths the finest hair-like (or feather-like) portions are seen distinct at or near the median line, but converging and intertwining towards the delicate membranous looking edge ? I have also sent two photographs of a Pinnularia and cast, by direct light, the one showing what I take to be the siliceous frustule, well defined; the other the so-called cast, well defined, * The photographs are deposited in the Library. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 839 the focus being altered slightly to take the latter. (In the figure the outer edge of the cast is too hard and defined.) They are represented by Fig. 148. The differences between siliceous frustule and cast are:—In the former, every portion is sharply and hardly defined. There is no appearance of beading; altering the focus Fic. 148, Fia. 149. sy = = fl) 1 ey 1A fi age A y bab S es 5 . NF metott 3 a ~ } [b= 2 =| + 5 : S| a. Sak Set tf So eile delle Willd “es ae } Hh 5 4 = a : VE iar =. - Be ro} Se ahd S —_ S Ca B =: ae es ZS =: ZS SNS: AS ONS Zi NG AS S } brings out shading, and different planes of definition, showing convexity and different curves. In the latter, the median line is very irregular and interrupted, though clearly defined. The striz are thicker, not hard edged, and show signs of beading. In many places they coalesce. The whole is well defined at the one focus, proving it to be comparatively in one plane. In the beginning of this year, when examining for selection a mixed strewed (dirty) slide from a gathering, I found a Navicula (Didyma ?), of which I have sent three photographs. It is re- presented in Fig. 149. Round it there appears to be a double gelatinous membrane, with radial arms extending from the siliceous frustule to the margin of the membrane, where they appear thickened. At A the arms of the lower membrane seem to show through the upper membrane, and form V’s with the arms of the latter. They are finer than those arms which appear single, but which I conclude are formed by the arms of one membrane covering those of the other. At B both membranes appear, the edges forming loops. At C the membrane and arms are much extended, the arms 840 SUMMARY OF CURRENT RESEARCHES RELATING TO forming the V’s being very fine. (D is dirt matter on the slide con- cealing portions of the membrane.) From the above and other observations I would suggest that the movement of some diatoms is carried out by means of an undulating and extensible membrane with radiating arms. It would account well for movements as yet unexplainable, as for instance, when a diatom is fixed by one extremity, and has the other end pushed aside by another diatom. When the force so exerted is suddenly removed, the first diatom springs back into the first position, like a bent spring released, as if acting by muscular power. Having cracked the cover-glass, I am unable now to use an immersion lens, but what I have mentioned is still visible with a good dry +4.” Mr, H. Mills has also detected* in Stephanodiscus Niagare fine threads twice the diameter of the frustule, as Professor H. L. Smith had previously done in the same object. Symbiosis of Animals and Algz.t—In pursuance of his investi- gations on the symbiosis of certain alge with the lower animals, G. Entz states that he has been able to detect in the pseudo-chloro- phyll-bodies of the infusoria two clear spots which must be regarded as contractile vacuoles. The view previously brought forward that their presence in animal organisms is due to their being taken in with their food is confirmed by the fact that they are scarcely ever found except in the mature individual. Almost the only exception to this is the case of Hydra viridis, where they occur in the ova. With regard to the designation of these organisms as parasites, the term can only be applied to them in a very wide sense, since they can live if removed from their host, which is not the case with true parasites. Vampyrella and its Allies,t—J. Klein has continued his obser- vations on the interesting genus Vampyrella,§ and furnishes many _ further details respecting the development of the different species. In V. variabilis, he observed that the zoospores sometimes conjugate into a plasmodium even before their escape from the cyst. If the zoospores fail to conjugate, after a considerable time they will put out one or two long slender pseudopodia instead of the much larger number of shorter ones, and by this means effect conjugation with other zoospores. V. vorax is parasitic upon diatoms, as for example Synedra; and. in this species the conjugation of the zoospores may be very well observed. They consume the greater part of the contents of the diatom-shell. V. pendula occurs on several species of Cidogonium, and exhibits essentially the same phenomena as the preceding species. V. inermis resembles pendula in being parasitic on Cidogonium, and * Amer. Mon. Mier. Journ., iii. (1882) pp. 8-9. + Biol. Centralbl., ii. (1882) pp. 451-64. Cf. this Journal, ante, pp. 241, 542. t Bot. Centralbl., xi. (1882) pp. 187-215, 247-64 (4 pls.). § See this Journal, ante, p. 544. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 841 in each cyst producing only a single zoospore. It differs in the original cyst-membrane having no spines. Associated with Vampyrella, the author found an allied organism, to which, from its resemblance to Monas amyli, he gives the name Monadopsis vampyrelloides. It consists of cysts from which zoospores escape in a manner very similar to Vampyrella, and Klein believes that it is a transitional. stage of development intermediate between this genus and Monas. Respecting the systematic position of Vampyrella, the author regards the genus as being most nearly allied to the Myxomycetes, but consist- ing of forms living in water. The species differ from both the Myxo- mycetes and the Chytridiacew in the absence of a cell-nucleus. They are organisms which are ordinarily propagated non-sexually by means of zoospores; the occasional conjugation of these indicating the commencement of a higher stage. An interesting difference from rhizopods, with which Cienkowski associates them, is that, unlike these low animal forms, they can only derive their nourishment from particular species of alge. They must, however, be regarded as presenting transitional forms between the animal and vegetable kingdoms. Special resemblances are pointed out to Monas amyli parasitic on Nitella, and to Protomyxa and Myxastrum which inhabit sea-water— all of which produce conjugating zoospores. Klein regards them as intermediate forms between Vampyrella and the true Myxomycetes ; while Nuclearta and Actinophrys are the most nearly allied forms among rhizopods. He proposes to establish a new family of Hypromyxacra, with the following characters :—Parasitic aquatic organisms, producing cysts, from which, when mature, one or more zoospores destitute of nucleus escape directly. At once, or at a later period, these assume an actinophrys or amceboid form, two or more coalescing with one another when meeting, and producing plasmodium-like bodies. The zoospores, as well as the plasmodia which result from their coalescence, form new cysts after absorbing nutriment. Subsequently, also, resting cysts are produced ; but these are not at present known in Monadopsis and Protomyxa. The family is made up of the genera Vampyrella, Monadopsis, Monas, and Protomyaa. The following are the generic characters :— 1. Vampyrella Cnk. The ripe cysts contain a red or orange endochrome, with dark spots ; membrane usually coloured blue by iodine and sulphuric acid. The endochrome escapes in from 2-4 (rarely more) pieces, which develope into zoospores, moving either by pseudopodia or by a colourless seam ; the division into zoospores takes place during the escape. In the coalescence of the zoospores, the pseudopodia first unite, and then the body; from 2-4 (rarely more) Zoospores conjugating in this way. Plasmodia small, usually resembling a large zoospore, and with neither vacuoles nor anasto- moses. The plasmodia and zoospores both develope into new cysts. Resting cysts are also known. Seven species. 2. Monadopsis Klein (only 1 species, M. vampyrelloides). Cysts 842 SUMMARY OF CURRENT RESEARCHES RELATING TO small; endochrome pale red; membrane delicate, coloured blue by iodine and sulphuric acid. Endochrome escapes simultaneously in two or three portions; the division taking place before the com- mencement of the escape. Zoospores very small, of irregular ameeboid appearance, with only a fewshort pointed pseudopodia. In conjugating the zoospores envelope the isolated cells of the host (unicellular alge), forming a new cyst round them, or several individuals are thus enveloped. Resting cysts unknown. 3. Monas Cnk. (only 1 species, Monas amyli, or Protomonas Haeck.). Cysts spherical, with simple thin membrane and colourless endochrome, from which a number of zoospores are formed. Zoospores, at first fusiform and bi-ciliated, with serpentine motion, after- wards amceboid or actinophrys-like, with several fine pointed pseu- dopodia and slow movements, during which they change their form. Small plasmodia formed from the coalescence of several amceboid zoospores. The hosts (grains of starch) are surrounded by the zoospores or plasmodia, thus forming a new cyst; several zoospores often coalesce on the same starch-grain. Resting cysts formed by the ordinary cysts throwing off the unconsumed nutrient material, and enveloping themselves with a new membrane, wart-like projec- tions appearing on the inner side of the original membrane. 4. Protomyxa Haeck. (only 1 species, P. awrantiaca). Cysts spherical, with moderately thick membrane, structureless, and not coloured blue by iodine and sulphuric acid. The fine-grained orange- red endochrome breaks up into a number of portions, each of which escapes as a zoospore. Zoospores pear-shaped, with a single cilium at the narrow end, and slow motion, subsequently amceboid and protean. Large plasmodia formed by the coalescence of several amceboid zoospores, furnished with branched anastomosing pseu- dopodia and vacuoles. The hosts (various diatoms) are surrounded by the ameeboid zoospores or plasmodia, and their shells thrown out after their contents have been absorbed; a new cyst is thus formed, a new membrane being excreted. Resting cysts unknown. MICROSCOPY. ‘a. Instruments, Accessories, &c. Petrographical, Mineralogical, or Lithological Microscopes.— Rosenbusch, Fuess, Beck, Swift, &c.—(1) Rosenbusch’s Petrographical Microscope.—-Special Microscopes for the examination of minerals and rocks are now supplied by nearly every optician. The original of such instruments* is the one devised by Professor Rosenbusch, in 1876,} which is illustrated in Fig. 150, with a few modifications introduced in its manufacture by R. Fuess, of Berlin.t * A “Mineralogical Microscope” was described by S. Highley in Quart. Journ. Micr. Sci., iv. (1856) pp. 281-6 (8 figs.). + Neues Jahrbuch f. Mineral., 1876, p. 504. $ Cf. Loewenherz, L., ‘Bericht tiber die Wiss. Instrumente auf der Berliner Gewerbeausstellung im Jahre 1879,’ pp. 282-6 (1 fig.), pp. 350-3 (1 fig ). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 843 Fic. 150. ~ BS o S ~ UN —S sd SSN SSM ETE ©. = |i IR ium 844 SUMMARY OF CURRENT RESEARCHES RELATING TO The chief advantages of the instrument consist*:—(1) In the facilities for turning an object in its own plane between fixed crossed nicols, the rotation being concentric with the axis of vision; (2) In the ability to read off accurately the angle through which the object may be turned in a horizontal plane by means of the graduation round the circular stage; (3) In the facility with which the polarizer and analyzer can be displaced and replaced, and the means by which the exact position of the principal sections of the polarizer and analyzer can be noted; (4) Where the total ex- tinction of light by means of crossed nicols interferes with the researches on any mineral, means are provided for facilitating ob- servation under such circumstances. The peculiarities in the construction of the Microscope consist in the tube which carries the eye-piece and objective b (Fig. 150), being as it were suspended within an outer tube p, its only attachment being at the top at 1. A block & is fixed between the inner and outer tubes to prevent any rotation during focal adjustment. The coarse adjustment is effected by hand, the thumb and forefinger sliding the inner tube up and down by pressure on the disk f, other fingers being applied to the top J, of the fixed tube. The fine adjustment consists of a micrometer screw, shown at g, graduated in 500 divisions, each being equal to 1 ». The unattached portion of the inner tube is steadied in the outer one by means of a spring + and three little screws a (see side figure, a section through M—N), set hori- zontally and capped with scraps of parchment, which are more or less compressed as the adjustment is made. The arm of the Microscope carries two screws with milled heads, one of which is shown at n, and both at n and min the side figure. These are set at right angles to one another, and serve to centre the tube. The eye-piece carries.two cob- webs, which intersect at right angles in the centre of the field. To the outside tube of the eye-piece a small peg a is fixed, which slides into a corresponding slot in the top of the inner movable tube of the Microscope. This arrangement prevents any rotation of the eye- pieces, and so keeps the cobwebs in a fixed position. An analyzer s, fitting in a brass cap, slides over the top of the eye-piece. The bottom of the cap is surrounded by a bevelled flange, which is graduated to 5°. An index mark on the plate f, serves to record the angle through which the prism is rotated. The stage of the Micro- scope is circular, and a circular plate T is arranged so as to revolve horizontally on it. This plate is graduated on its margin, and an index to record the amount of the revolution is attached to the front of the fixed stage at i. It also has a spring clip g, and a Wright’s indicator (two scales at right angles). Beneath the stage is set an easily displaceable polarizer r, consisting of a Nicol prism, which revolves within its external tube by means of the lower disk, which is graduated to 10°, and has its index marked on the fixed outer tube. This polarizer does not turn when the stage plate is rotated, but * See Rutley’s ‘Study of Rocks’ (8vo, London, 1879) p. 54. + In the figure, in order to show the spring, it is brought too far round by 45°, ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 845 remains unaltered in position. A plate of quartz for circular polarization 3:75 mm. thick, and mounted in a little brass fitting, is shown at z. It slides into a slot ¢, situated close to the lower end of the inner microscope-tube and above the objective. The movement imparted to the microscope-tube by the screws n m, tends to throw the analyzer slightly out of position with regard to the polarizer, but Professor Rosenbusch finds that this produces scarcely any appreciable error. For very strongly convergent light, the ordinary condensing lens (with a focus of 12 mm.) attached to the Nicol, is combined with a second one of only 8 mm. The axes to these mineral sections can thus be recognized without an eye-piece and with the objective alone.* The stauroscopic eye-piece is shown in the side diagrams A and B of Fig. 150. The eye-lens is attached to a separate tube sliding in that holding the field-glass, and can be brought closer to the latter. The tube of the field-glass has a slit in which a pin a, inserted in the eye-lens tube, slides. The pin also passes into a slit in the micro- scope-tube, and thus fixes the position of the eye-piece. At cisa plate of calc-spar in the focus of the eye-lens. This was first used by Professor Calderon for stauroscopic measurement, and afterwards adapted to the Microscope by Fuess. For the purpose of accurately indicating to the eye the correct position with regard to the optical axis of the instrument, a cap with a very narrow diaphragm d is added, there being another diaphragm at c. Professor Rosenbusch points out that the use of this Microscope is not confined to the purpose for which it was designed, but that it is also available for other microscopical purposes where exact measure- ments are required. (2) Fuess’s “large Microscope for mineralogical and petrographical observations” (Fig. 151), is designed as an improvement upon the pre- ceding, especially as regards the stability of the centering arrange- ment. The sliding coarse adjustment is done away with, and instead of it, the stage c with the illuminating apparatus is attached to the slide d which moves on the upright support f of the stand to a distance of about 1°5 cm. (by means of the rack-work attached to d and actuated by the pinion e), and is held in the required position by the clamping screw behind. The fine adjustment is effected by the usual graduated micrometer screw. By the use of intermediate pieces of tubing the objectives can be so attached to a horizontal revolving plate a, that they all stand at about their focal distance from the object if the slide is of ordinary thickness. The centering of each objective with the optic axis of the tube b is then effected by three adjusting-screws below the revolving-plate, so that the arrangement * See this Journal, i. (1878) p. 207. t The graduation of the micrometer-screw and the addition of the plate of calc-spar and the Wright’s indicator, appears to have been suggested by Professor A. v. Lasaulx. Cf. Bull. Soc. Belg. Micr., iv. (1878) p. elxxvi. The Microscope described by M. Renard, Bull. Soc. Belg. Micr., iv. (1878) ecxv., and this Journal, i. (1878) p. 270, appears to have been a Rosenbusch-Fuess instrument, but with the Lasaulx improyements and the addition of the quartz plate, Ser. 2.—Vo., II. a 846 SUMMARY OF CURRENT RESEARCHES RELATING TO at the lower end of the tube of the Rosenbusch instrument is un- necessary. The diaphragm and polarizer can also be centered by means of the rectangular stage movements actuated by the milled Fie. 151. in le Hh ; \ Mi | / | ill Il | 4 j S G MULT mo —————— SSS ||P = = SSSSSSSSSSSSSSaqaSaSaSsS=SaSsSSaSaSS——SSSSSS—S-S-_-SS-S-S==—_—_—S=S= ——=——SSSLHH][_HSSSSSSSESSS]S]]LSL_]S]—SLSS85 SSSsssese_HSESSS = ————— —= eee ————— = — ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 847 heads m and n. The former movement is made to do duty as a screw-micrometer, having a drum p attached, engraved with 125 divisions, each having the value of 0°002 mm., the screw pitch being 0°25mm. The revolutions of the screw can be read off on an index @. The margin of the stage is graduated and also dentated, so that it can be turned by the finger. For convergent light, two Bertrand lenses of 12 and 8 mm. focal length are placed above the polarizer, and a third above the objective.* Fic. 152. (8) Beck’s Lithological Microscope (Figs. 152-4).—This instru- ment (Fig. 152) is modelled on the plan of the “ Economic” Micro- * Cf. this Journal, i. (1878) p. 292, 3L 2 848 SUMMARY OF CURRENT RESEARCHES RELATING TO scope with the alterations necessary to fit it for lithological examina- tions. The coarse adjustment is effected by the usual rack-and-pinion, and the fine by a micrometer-screw with a divided milled head, repre- senting thousandths of an inch, for the approximate measurement of sections, &c. The stage is divided on the edge to degrees, and has a vernier reading to 10’, adapting it for use as a goniometer or for stauroscopic measurements, &c. It rotates concentrically with the optic axis, and to compensate for any slight variation in centering there is a centering nose-piece. Immediately above the latter is a Klein’s quartz plate fixed on an arm by means of which it can be Fie. 154. turned up out of the field with great facility as shown in Fig. 153. One of the three milled heads at the end of the body-tube effects this movement. The other two milled heads are for centering the objective, and their action is shown in the same figure. The analyzer rotates freely over the eye-piece (Fig. 153), and has an index which by a divided plate on the draw-tube allows it to be read in any position and recorded. Between the analyzer and the eye- piece is placed a plate of cale-spar cut at right angles to the optic axis for stauroscopic measurements. ‘The eye-piece has cross cob- webs. The rotating polarizer also has a divided circle to register its position, and it is fitted into a swinging are which is in contact with the bottom of the stage, thus excluding any false light. By means of a hinge it can be instantly turned away from the stage (in the way shown in Fig. 154) when ordinary illumination is required. A condenser of large aperture, fitting into the tube of the polarizer above the prism, is intended for the examination of the interference brushes and rings in crystals with convergent light. This also is easily removed when not required. When the instrument is used for this purpose a lens is screwed into the lower end of the draw- tube. The instrument, though specially constructed for the study of rock sections, can be used for any other work. It is only necessary to remove the analyzer and polarizer. The fitting on the swinging arm which carries the polarizer will take any other substage apparatus such as parabola, achromatic condenser, &c. ee ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 849 (4) Swift's Petrological Microscope (Fig. 155).—The general basis of this is Mr. Swift’s well-known “Challenge” stand (see Vol. I. (1881) p- 810). Aspecial arm carrying the polarizer is added so that it can Fig. 155, 850 SUMMARY OF CURRENT RESEARCHES RELATING TO be readily turned away when not required, and a tube inserted in its place for sub-stage apparatus. The fitting of the polarizer is graduated and a spring catch indicates when the prisms are crossed. The rotating glass stage is graduated, and has a ‘“self- centering ” arrangement. Two sliding boxes at the lower end of the body-tube serve to carry the analyzer and, below it, a Klein’s quartz — plate, which ean thus be readily slipped in and out. An extra analyzing prism with divided circle is placed over the eye-piece (which has crossed spider-lines) with a contrivance for rotating crystals between it and the prism. There is also a new arrangement for showing the rings in biaxial crystals of extreme wide angle, diopside for instance, with its entire system of rings being (it is claimed) “exhibited as large and with ereater brilliancy than with Noérremberg’s Polariscope.” For this purpose an achromatic lens is interposed by means of a supplementary draw-tube between the eye-piece and objective, an optical combination of large aperture being fixed over the polarizer. Mr. Bulloch, of Chicago, has also issued a Microscope for the study of rock sections, adapting for the purpose the model shown in Fig. 140 of Vol. III. (1880) p. 1077. Cf. also Rutley’s, Vol. II. (1879) p. 470, Nachet’s Petrographical Microscope, Vol. III. (1880) p- 227, and Vérick’s Goniometrical Microscope for Mineralogy, Vol. I. (1881) p. 812. ‘Jumbo’ Microscope.—The instrument, from Mr. Crisp’s col- lection, shown in Fig. 156 (about } nat. size) is another of the numerous instances of misdirected ingenuity in the designing of Microscopes. It was made in 1851 by G. Lowden, junr., a Dundee optician, for a gentleman then lately returned from India. It stands 4 feet high, weighs 13 cwt., and the body-tube is 4 inches in diameter. It is therefore entitled to the distinction of being the largest and heaviest Microscope made within modern times !* For the coarse adjustment the stage is moved up and down along . the bar which supports the body-tube, its movement being controlled by the large milled head on the upper end of the bar. The fine adjustment is worked by the milled head and rod attached to the body- tube, by which an inner tube carrying the objective is raised or lowered. As the stage is so far from the observer its movements are effected by the two longer rods terminating in milled heads shown in the figure above the end of the bar. One of these moves the stage from back to front, the other turning it to either side on a pivot at its base, giving it therefore a movement in a segment of a circle. The re-. maining shorter rod has a screw at its lower end which, working in a toothed wheel on the axis, causes the body of the instrument to incline as may be desired. ‘The eye-piece is pierced with a slit to admit a slide holding prepared paper for “calotyping” an object by the old paper process. * Schott, ‘Magia Universalis,’ 1677, describes and figures Microscopes of enormous size, ZOOLOGY AND BOTANY, MICROSCOPY, ETC. THE MIDGET Hl ill — ———, a NTT TT THE JUMBO. 852 SUMMARY OF CURRENT RESEARCHES RELATING TO “ Midget’ Microscope——Fig. 156 also shows this Microscope to the same scale as the previous one. It was made by Mr. 8. Holmes, and is only 4% inches high with a diameter of body-tube of less than 1 inch. It is probably the smallest working instrument ever made. Beck’s Histological Dissecting Microscope—This instrument (Figs. 157, 158) combines a compound with a simple and dissecting Microscope, the stout arm holding the Fie. 157. single lenses being made so that a com- = pound body (fitted with “Society” screw ) can be substituted. A speciality consists in the adjustment of the mirror, which ean be used as in Fig. 158 for transparent objects, or can be brought above the stage as in Fig. 157 for opaque ones. Fic. 158. Gundlach’s Globe Lens.*—This is a perfect sphere, consisting of a hollow flint-glass globe, made in halves, and enclosing a solid crown-glass globe. It is said to be constructed “ according to a new optical principle discovered by Gundlach. By this principle the aberrations are corrected to a higher degree than has heretofore been attained by any other construction. The lens has an optical axis in any direction, hence the field is perfectly flat and distinct to the outer edges; and what is true of no other lens, the field is always the largest possible.” There are five sizes, 1, 2, 3, 3, and 4 inch. * «Descriptive Price List of Gundlach’s New and Improved Objectives,’ March 1882, p. 8. XN ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 853 Designation of Eye-pieces.*—At the Elmira meeting of the American Society of Microscopists, Dr. R. H. Ward, the chairman of the committee on eye-pieces (ante, p. 103), reported, that “all manu- facturers but one had agreed to designate their eye-pieces by their focal-lengths, but no agreement had yet been madeas to the diameter of the tubes.” The committee was continued for another year. Objectives of small and large Aperture.;t—The Rev. W. H. Dallinger writes on this subject as follows:—“ No one has appre- ciated or found more pleasure and profit in the use of the large angles with which our lenses have been more and more perfectly provided for the last ten or twelve years than I have. As they have been produced I have obtained them each and all, that had any real value, whether produced in this country, the Continent, or America, and in some cases I have incited certain English makers to produce certain special formule during that time. But while I have used all lenses, from the + to the ,, constantly during this time, what work I have done could never have been accomplished if I had only had lenses with large angles to work with. Much that had been done could never have been done without them; but the work, as a whole, could never have been done at all if only such had been at my disposal. Hence I have, in all my special working powers, three lenses of the same power, and in some cases four, and each of them, in following out the details of a life-history of an organism, say of the 5,5, to the ;.), of an inch in length, is absolutely needed, and its place cannot be supplied by the other. Thus, I have two »,ths, one having a very low angle, and the other as great a numerical aperture as an oil-immer- sion can provide when worked by the best makers. In the =};th, I have but one lens, a medium angle, because it was intended only for general work and, mainly, central illumination. Ihave, however, three ths, four ~,ths, and so on; and I know exactly what each will do, and no more attempt to get the work of one out of the other than the maker of them would attempt to get their several results by — grinding them to the same formule. I talked this matter over in detail, pointing out results, six years ago with some leading experts; and although, during two or three years, many have thought that Abbe’s mathematics and views were adverse to this view of mine, I felt convinced by reading between the lines of his papers, and remembering their special object, that it was not so. Still Dr. Carpenter was good enough to get a detailed view of my experience and opinion before publishing the last edition of ‘The Microscope,’ and he has in his preface and throughout the volume, given in effect my views, which now the unmistakable decla- rations of Abbe coincide with and confirm. The homogeneous lenses have given me splendid results, some of which will shortly be published ; but no immersion lens of any kind could be used to work out to the end an organic life-history—that is, if it involved life and movement, because the object being in a limited area, and possibly in fluid, the fluid under the cover does (when the movements of * Amer. Mon. Micr. Journ., iii. (1882) pp. 175 and 171. + North. Microscopist, ii. (1882) pp. 288-9. 854 SUMMARY OF CURRENT RESEARCHES RELATING TO the object are followed) at length, without the spectator’s knowledge, mingle with the fluid above employed for the lens, and thus destroy the whole object of search and study. This fact, then, makes air angles of the highest importance, and I hope the highest results have not yet been attained with them. In the main, then, I agree with Abbe.” At the Montreal Meeting of the American Association for the Advancement of Science, Dr. W. B. Carpenter gave an address on the practical and theoretical results in the history of the Microscope, in which he dwelt mainly upon the question of wide aperture and high power eye-pieces. Correction-adjustment for Homogeneous-immersion Objectives.* Dr. L. Dippel has already briefly published his objections to the use of a correction-collar in the case of homogeneous-immersion objectives (in opposition to the contrary opinion of Dr. H. Van Heurck) which he considers to be an abandonment of the practically most important advantage for scientific work which homogeneous-immersion has brought us, but is now led to return to the subject by the recent publication of the views of Dr. G. E. Blackham 7 (also of Dr. J. Edwards Smith t), in favour of the retention of the correction-collar, and he accordingly discusses the subject in some detail. If we consider the matter first from the side of theory, it must on the one hand be allowed that the correction-collar, from a purely theoretical point of view, may have certain (though as will be seen in the sequel practically unimportant) advantages, while on the other hand it is undoubtedly the fact that the other advantages ascribed to it must be regarded as imaginary. The advantages relate essentially to ie following points :—First, with the correction-collar we are not so strictly limited to an im- mersion fluid of a particular index of refraction, as we are in the case of the fixed mounting, but various fluids can be used, which are different within certain—though always very narrow—limits. In the use of an immersion fluid not precisely of the same refractive index as crown glass (which is the case with most of the immersion fluids hitherto employed, except the thickened cedar-wood oil), we can still obtain perfect correction for cover-glasses of varying thickness. Further, those aberrations (comparatively considerable) can be corrected, which occur with dry preparations (rarely, however, coming under consideration in the scientific use of homogeneous immersion), if they do not adhere closely to the slide, but are separated from it by a thin stratum of air. Finally, the correction-collar allows the same objective to be used with a longer or shorter tube, while otherwise one is confined to somewhat narrow limits in the length. All the other advantages, however, urged by the advocates of the correction-collar are only imaginary, such as the possibility of most exact correction for the change in the index of refraction of a par- * Zeitschr. f. Instrumentenk., ii. (1882) pp. 269-74. + Cf. this Journal, ante, p. 407. vases } ‘How to See with the Microscope,’ 1881. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 855 ticular immersion fluid, in consequence of variations in temperature ; or of an alteration in the optical properties of the cover-glasses, and the different powers of accommodation of the eyes of different observers. The author has already shown* the practical insignificance of the difference in the refractive index of the immersion fluid produced by the varying temperature of the observing room in the ordinary use of the objectives in question, where the changes of temperature cannot be very important. Theoretically considered also, the matter will be seen to be of only little moment. According to the measurements of Professor Abbe, the difference with cedar oil is but 0°003 for a variation in temperature of 3° C. Since the correction of the ob- jectives is arranged for a medium temperature of from 18° to 20° C., and the temperature at which normal microscopical observations are made is certainly (even if we allow very wide limits) between 15° and 28° C., the greatest deviation from the mean value in the refractive index is at most two or three units in the third decimal place. The aberrations in the divergence of the incident rays connected with this slight change and the consequent disturbance of the spherical cor- rection, whilst it can be demonstrated by very accurate testing on the silver plate, is nevertheless in any case much smaller than those devia- tions from the best correction which occur with the correction-collar. It therefore follows that this much enforced deviation in the refractive index of the immersion fluid, caused by variations of temperature, which is to be balanced by the correction-collar, is at all events the lesser of two evils, and consequently can furnish no pretence for doing away with the fixed mounting. Still less than the above-mentioned variations can the differences in the refractive index of different cover-glasses give any inducement for the introduction of the correction-collar. According to the observations of Professor Abbe during a period of ten years, these differences are so extremely small that they may be regarded practically as nil. Finally, the suggested influence of the different powers of ac- commodation of the eye must be relegated to the region of dreams, as a simple theoretical consideration will show. If we take for example a power of 800, and two observers whose eyes are accommodated respectively to 100 mm. and an infinite distance, the difference in the adjustment thus produced—that is in the actual object-distance, assuming the objective to have air on both sides of it—can be easily computed from the formula :— eS For a long-sighted eye (where «* = o) a =O. For a distance of vision of 100 mm. (where «* = — 100) a 25 C= , and since in the Microscope as a whole f = oe , 100 N °c ae se =(3) +300" * Bot. Centralbl., No. 6. 856 SUMMARY OF CURRENT RESEARCHES RELATING TO Consequently, in the case assumed above of a power (N) of 800, a is rather more than 0:0009 mm. (or 0°9 yz), or if the object is in a medium of n = 1°50, not quite 1:5. This exceedingly slight displacement of the focus forms the measure of the alteration in the path of the rays in the objective, and it is the aberra- tion which corresponds to the difference in the visual distance, assuming that accurate correction is first made for « = 0: much less if the largest possible aperture is assumed for that x, and generally not ascertainable, since it depends, like the moving of the lenses towards each other (by the correction-collar) upon the particular construction of the objective. Let us, however, assume that this movement of the lenses which is necessary for the equalization of the very slight difference in the path of the rays corresponding with the above ascertained difference of adjustment (and of the consequent disturbance of the spherical correction), amounts to even 0°1 », or 0°0001 mm., which is certainly far too high, this would still be a quantity which is unattamable by any mechanical contrivance, least of all by such a mechanism as the cor- rection-collar. If Dr. J. Edwards Smith adduces against the results thus established by theory, a case in which three divisions on the scale of the correction-screw would be required for the equalization of the difference between the power of accommodation of his own eye and that of another observer (Mr. C. Spencer), it must be said that such a thing is entirely absurd. It proves in fact simply that what he regarded as the action of different powers of accommodation, was nothing more than an effect of “personal equation” in the judgment of the best image, and therefore rests entirely on purely subjective opinions. Tf we now further examine the matter from a practical point of view, it may be at once allowed that the technical considerations against the correction-collar are not so weighty that it should be set aside on that account if really practical advantages were to be gained by it. For even if the greatest perfection of centering (such as is possible with the fixed mounting) cannot be obtained with the cor- rection-collar nor its durability guaranteed, yet according to the examination by Professor Abbe of the correction-objectives of Powell and Lealand and Zeiss, a sufficient amount of accuracy can be obtained by very careful work. The question of expense, which the author previously laid stress on, need not be considered, because, as Professor Abbe observes, the technical difficulties in mounting the fixed ob- jectives (on account of the final adjustment of the distances of the lenses to fractions of a hundredth part of a millimetre), are not less than in those with the correction-collar, and therefore the price for both kinds is about equal. In this respect, therefore, there is nothing to urge against the introduction of the correction-collar. Now, however, the question arises, how and to what extent the possible advantages suggested by theory can be realized in practice without prejudicing the usefulness of the objectives, and on this point the author is strongly convinced that in the proper scientific use of the Microscope for the examination of unknown objects and structural ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 857 elements, the advantage to be expected by the use of the correction- collar is not only absolutely illusory, but that it is attended with many serious disadvantages. In the observation of diatoms, which one has seen so often, and the structure of which is so simple and characteristic, it is not a matter of great difficulty to find approximately the best correction by experiment, since one forms a judgment from the clearness and dis- tinctness of the image. For those, therefore, who study preferably the structure of diatoms, or who have set themselves the task of demon- strating test-objects a number of times (from whom has originated the desire for this contrivance), the correction-collar may prove of some slight advantage in the sharpness of the image, and for that reason may appear to bea desirable requisite. For this class of observation it may be readily admitted that at least no important disadvantage can arise. For histologists, however, the case is very different. With the objects that come under their observation, especially if they are of very delicate and complicated structure, it is almost impossible to find the best correction by mere trial. In endeavouring to find the “ best image ” we are just as likely to arrive at a completely false correction (which produces false images) as upon the proper one. The widest latitude is thereby given to every possible subjective fancy and false arbitrary interpretation, and those deviations from the best correction which still remain, in the in other respects skilful use of objectives with fixed mounting and carefully corrected for a given length of the tube and a particular immersion fluid, are perfectly insignificant and harmless as compared with the great uncertainty and grave aberra- tions which the use of the correction-collar introduces. If the best correction for a certain thickness of cover-glass is required, there is only one object by means of which this can be obtained with perfect certainty and with the smallest amount of sub- jective fancy, so that correct images of all objects of any structure can be guaranteed (without false differences in level, &c.). This object is the Abbe test-plate, by which the correct co-operation of all zones of the aperture can be judged of. That, in comparison with this plate, the structures of the valves of the Diatomacez are by no means suffi- cient, is best proved by the case brought forward by Dr. Edwards Smith, in which personal equation evidently played no unimportant part. And if even in the case of such an object—strie of diatoms of well-known nature—such latitude was given for the exercise of personal caprice in the adjustment of the correction-screw for the “ best image,” how great may it be when we are dealing with unknown delicate and complicated structures ? Under such circumstances, how easily may the employment of the correction-collar become rather a subject of misuse than of use? With high power dry objectives and water-immersion objectives the correction-collar is a necessary evil which must be endured. Where, however, it can be dispensed with, it would be folly to retain it on account of entirely subordinate and unimportant advantages. Especially may it be very decidedly rejected in all scientific work with homogeneous-immersion objectives. The slight restriction in the use of objectives with fixed mounting can the 858 SUMMARY OF CURRENT RESEARCHES RELATING TO more be endured, since on the one hand each of such objectives can be adjusted according to desire for the short Continental or for the long English tube, and thus effect can be given to personal inclinations ; while on the other hand, where it is a question of sharpest observa- tion, it is éasy to provide a suitable medium thickness of cover-glass where the immersion fluid is not exactly uniform with crown-glass. Under all circumstances one gives up in using the fixed mounting only unessential conveniences and benefits hardly worth consideration, whilst far greater advantages are gained and very considerable defects avoided. In conclusion, therefore, Dr. Dippel repeats:—‘“ or all histolo- gical and similar scientific observations, hold firmly to the fixed mounting for homogeneous-immersion objectives. And if we have such an objective with correction-collar, I say with Prof. Abbe, ‘ after careful testing of the best correction for mediwm conditions by means of the silver plate, screw it up tightly (“niet und nagelfest,” clinched and riveted), so that no mischief can arise’” * ~ Nelson’s Adapter for Rapidly Changing Objectives.—This ap- pliance has been devised by Mr. EH. M. Nelson to facilitate the rapid interchange of objectives without the necessity of triple or quadruple nose-pieces, or such an alteration of the existing system Fic. 159. as would prevent the free interchange of objectives provided with the normal Society screw, as is the case with the devices of Parkes, Nachet, and Vérick. In Fig. 159 N is an adapter,j the inner screw- thread of which is filed down smooth in three equal and equidistant segments, leaving the thread intact in the intervening three segments. The screw- thread on the objective is filed down in three places ; to correspond with N, so that where the gauge-slots ie S and §’ coincide the objective can be pushed in for 7 iiir the length of the screw, and then an eighth of a i turn to the right screws it securely “home,” just as ™™ it would be after the four turns required with the Society screw and ordinary nose-piece. Similarly to detach it, only an eighth of a turn to the left is necessary. Whilst the objective can be inserted at any of the three positions in which the segments of the nose-piece and objective coincide, it is only in the one position where the gauge-slots S and 8’ coincide, that the screw-threads correspond, and the one-eighth turn for screwing “home” can be made without injury to the threads.} . * Of. the discussion on this paper, Proceedings, post. + By a mistake of the engraver the outer screw of N is drawn of less diameter than that of O. They are both of Society gauge. + Since the construction of the adapter, Mr. Nelson’s attention has been - ealled to a communication in ‘Science-Gossip,’ 1879, p. 18, in which Mr. James Vogan suggested a similar system under the heading “A Substitute for Nose- pieces.” The plan then proposed by Mr. Vogan involved cutting away two segments of one-fourth the circumference of the screw-thread. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 859 If the thread of the nose-piece of the Microscope is filed down in the same way as in the adapter N, the latter may be dispensed with, and it is,as we have said, a special feature of Mr. Nelson’s suggestion that the alteration to the objective thread in no way hinders its use with the ordinary nose-piece, and unaltered objectives will in the same way fit nose-pieces which have been filed down. Gundlach’s Calotte Diaphragm.—Mr. Gundlach has devised the very neat form of calotte diaphragm shown in Fig. 160, for application to his “College” Microscope (ante, p. 670). Fic. 160. The calotte C is pierced with five apertures, varying in size from a pin-hole to 4 inch, and is attached to a hollow metal hemisphere H, by a screw at a point 45° from the vertex, which allows it to rotate so that the apertures pass succes- sively over an opening O at the’ i top of the hemisphere. H itself a is fixed to a spherical segment of metal, and the latter to a short piece of cylindrical tube so as to slide into the substage R; an outer shell §, of ebonite, rotates round H, and the edge of the calotte C being milled and in close contact with §S, the rotation of the latter causes the calotte to revolve also. A projecting pin on the tube fits into a slot in the substage ring to prevent H from rotating. More space for the hand between the stage and the outer edge of the ebonite shell would be obtained by adopting a conical instead of a spherical form of shell. Bohm’s Wool-measurer.* — This (Fig. 161). is intended for Fig. 161. 0 ARUN ‘| examining the wool of sheep under the Microscope, but it can also be used for the anthropological comparison of human hair, as well as for * Bericht u. d. wiss. Instrumente a. d. Berliner Gewerbeausstellung im Jahre 1879 (Loewenherz, 1880) pp. 313-4 (1 fig.). 860 SUMMARY OF OURRENT RESEARCHES RELATING TO other fibres. The hair or fibre is placed between two pincers a (exactly at their points). One of these is movable on the base-plate ¢, by means of the screw 6, and the object can therefore be stretched, and the extent of the stretching read off on the scale on the plate. As, moreover, they each move on their axis, the object can be uncurled in case it is twisted, and the movement registered on a scale on the end of the screw d, to which an index is also attached. In order. to be able to measure the various diameters of the object, it is necessary sometimes to turn it entirely round. For this purpose the bar e is added, whose two milled heads f are pressed towards the correspond- ing ones of the pincers a by means of the screw g, so that they act like cog-wheels. The simple turning of the bar e by means of the third milled-head h sets both the pincers in equal rotation. This instrument also provides means for chemical treatment. For this purpose the base-plate has two spring-pieces / for the reception of a small slide. 'These supports are raised up when the pressure of the screws m is released, so that the object may lie on the slide. A glass cover can be placed over it, and the object treated in the usual way with alkalis, acids, &e. By sliding the apparatus upon the plate n (clamped to the stage of the Microscope), the object can be passed across the field. Gundlach’s Substage Refractor.*—The formula in the descrip- tion of this apparatus at p. 692 was taken verbatim from the original source, and in the bibliography at p. 699 we noted a further article by Mr. Gundlach (with a different heading) as “apparently the same as the preceding.” On comparing the two articles, however, it will be seen that the earlier one was somewhat hastily prepared, and that the formula should stand as in the later one as follows :— “ Hor the determination of the angular aperture of objectives, if not less than 96° in crown glass, I propose to attach to the front surface of the objective, by means of a ‘ homogeneous’ medium, in the usual way, a small piece of crown glass, which has, besides the adhering surface, two other polished plane surfaces at right angles to the former and parallel to each other, with a distance between them of at least the diameter of the front lens of the objective. Then from two distant points, lying in the plane described by the optical axis of the objective and the perpendicular upon this axis and the parallel plane surfaces of the glass piece, let rays of light fall upon these surfaces, to pass through the glass and then through the objective. ¢ Find, in the usual manner, by moving the lights sideways, that direction of the two light rays by which the latter will just strike the outer edge of the aperture of the objective. Then determine the angle described by the two rays before entering the glass piece, and find the true crown-glass angle of the objective by calculation after this formula :— COS 7 —— = C08 a, Ue i being half the angle of the two rays before entering the glass piece ; * Amer. Mon. Micr, Journ., ili. (1882) p. 176. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 861 r, the refractive index of the glass piece; a, half the crown-glass angle of the objective.” Apparent Size of Magnified Objects.*—Prof. W. H. Brewer read a paper before the Section of Physics, at the Montreal Meeting of the American Association for the Advancement of Science, in which he gave the results of a long series of experiments on the apparent size of the image formed in the Microscope, as seen by different persons. About 440 different persons were questioned as to the size of the image of various objects, but finally a small insect was selected as the test object. The actual length of the image, as drawn by the camera lucida, using a 14-inch objective, was 4°66 inches, including the antennw, 4°87; the diameter of the field was 5°85 inches. The results may be briefly summed up as follows:—Of the 440 persons, about 41, or 9 per cent., judged the size quite correctly; 82 of them, or 19 per cent., made the size 4°25 to 5 inches, which was reasonably good. The greater number of persons underestimated the size ; 2 estimated it at less than 1 inch, 7 made it over a foot, 45 made it 2 inches, or less; 22 made it 10 inches. The largest estimate was by a mechanic, who said it looked like a picture projected on a screen and it seemed to be 5 feet long. Experience seems to correct false estimates, as was illustrated by three estimates by a gentleman who used the Microscope in drawing; in three successive years his estimates were respectively 9, 8, and 7 inches. Committee on Ruled Plates.—At the meeting of the Section of Histology and Microscopy of the American Association for the Advancement of Science, at Montreal, after the reading of a paper by Professor W. A. Rogers on ruled lines, a resolution was proposed that a committee be appointed to receive ruled plates from different makers that might be offered for examination in accordance with the sug- gestions made by Professor Rogers. After some discussion the resolution was carried, but it was afterwards decided to postpone the appointment of the committee until some future time. Professor R. Hitchcock regards this t “as a great step toward the settlement of the question of the practical limit of resolution, inde- pendent of any theoretical considerations,” and “ hopes and believes that at the next meeting of the Association a committee will be appointed.” Quekett Microscopical Club.—It has been determined to give a series of demonstrations upon elementary subjects connected with Microscopy on the “Gossip” evenings of this Club. The first six will be on the following subjects :—Dec. 8, 1882, The History of a Stained Section of an Animal Structure, by Mr. J. W. Groves. Jan. 12, 1883, Photo-micrography, by Mr. T. Charters White. Feb. 9, Sea-side Collecting, by Mr. A. D. Michael. March 9, Some Methods of Preparing Parts of Insects for Microscopical Examina- tion, by Mr. E. T. Newton, April 13, Microscopical Vision, by Mr. * Amer. Mon. Mier. Journ., iii, (1882) p. 161. t Ibid., pp. 197-8. Ser. 2.—Vo1. IT. 3M 862 SUMMARY OF CURRENT RESEARCHES RELATING TO W. T. Suffolk. May 11, The Structure of Mosses, by Dr. R. Braith- waite, : We are glad to find that this experiment is at last to be tried. That it should be done has been for several years the strong wish of many of the members. As, however, it was found that the suggestion gave offence to leading officials of the Club, it was not further pressed, in the hope that at some future time the force of events would enable the question to be dealt with on its merits and apart from any personal predilections one way or the other. Hogg on the Microscope.*—A new (10th) edition of this book (bearing the date of 1883) has just been issued. It is now so well known from the numerous editions through which it has passed, extending over a period of nearly thirty years, that it is superfluous to describe its general plan. The new edition bears the marks of extensive revision, especially in the parts relating to the Microscope proper, which have in fact been nearly rewritten. It is almost unnecessary to say that the book contains that without which no treatise on the Microscope is now complete, viz., an explana- tion of the Abbe theory of microscopical vision, and of the pons asinorum of the old school of microscopy—the aperture of objectives. Pages 69 to 80 are devoted to the most succinct and at the same time complete statement of the latter subject that has yet been printed. A similarly succinct statement of the principles on which homogeneous- immersion is based is given in pages 82 to 86. A chapter has been added on the application of the Microscope to mineralogy and spectro- scopic analysis and the examination of potable water. By a slip the preface omits to mention that more than fifty of the new woodcuts were lent by the Council of this Society, having originally appeared in this Journal. : The author may be congratulated on the issue of the new edition and on the fact that his book has so long maintained so large an amount of popularity. Wright’s Experimental Optics.j—This is also a book on which the author may be very much congratulated, as in our view it is by far the most useful work on its subject to which the general body of microscopists can refer. It is written throughout from an experimental point of view, and the author’s endeavour (to use his own words) has been “to place clearly before the mind of the reader, through something like a complete course of actual experiments, the physical realities which underlie the phenomena of Light and Colour. As helps, there are solely employed simple mechanical analogies, and a few diagrams, explained in language which it is hoped may be found in reality simple and clear though not intended to be childish or to debar any private student from the healthful exercise of now and then consider- ing what the writer means.” We think that the author’s explanations * Hogg, J., ‘The Microscope: its History, Construction, and Application.’ New (10th) ed., xx. and 764 pp., 8 pls., and 356 figs. (Svo, Routledge, 1883). + Wright, L., ‘Light: a course of Experimental Optics, chiefly with the Lantern,” xxiy. and 367 pp, 8 pls., and 190 figs. (8vo, Macmillan, 1882). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 863 will enable those who are new to the subject to master it more readily and satisfactorily than they could do by the more usual mode of treatment adopted in the ordinary text books. The phenomena of polarization occupy 148 out of the 358 pages of the text, and this section is illustrated by 62 figs, and 6 plates, 2 of which are beautifully coloured. There is an Appendix on ‘ Dif- fraction in the Microscope,’ condensed from this Journal, I. (1881) pp. 350-5. Brappury, W.—The Achromatic Object-glass. XI. Lingl. Mech., XXXVI. (1882) pp. 219-20, Braintree Microscopical Society. {Note on the first Annual Journal and Report.) Sci.-Gossip, 1882, pp. 231-2. Brownine, J.—Letter on the Small Loss of Definition by using B, C, and D Eye-pieces. North. Microscopist, II. (1882) p. 282. Buttocn’s (W. H.) Newer “ Congress” Stand. This Journal, ante, pp. 666-9 (5 figs.). Engl. Mech., XXXVI. (1882), pp. 151-2 (1 fig.) Croucu’s (H.) Students’ Microscopes, and how to use them. Catalogue (n.d.), pp. 25-34 (figs.). CrumBaueGH, J. W.—The History of the Microscope and its Accessories. III. The Microscope, II. (1882) pp. 115-7. D., E. T.—Drawings and Paintings from the Microscope. [Post.] Sci.- Gossip, 1882, pp. 1-3. » 9 Microscopical Painting. [Post.] Sci.-Gossip, 1882, p. 230. Dauiincer, W. H.—Letter on Objectives of Small and Large Aperture. [Supra, p. 853.] North. Microscopist, II. (1882) pp. 288--9. Davis, G. H.—Apertures and Amplification. [Comments on paper of J. L. W. Miles, infra; also remarks on Professor Dunean’s Presidential Address—“it is so clearly expressed that we commend it to the notice of members of all Societies both young and old.”] North. Microscopist, 11. (1882) p. 278. £5 # The Elements of Microscopy. I. The Human Eye. North. Microscopist, II. (1882) pp. 293-303 (12 figs.). “ Density ”— Micro-photography. [Inquiry whether the visual and actinic foci of an objective are the same distance apart whatever the distance of the sensitive plate from the objective. ] Engl. Mech., XXXVI. (1882) p. 282. Dreret, L.—Eine neuere Verbesserung der Abbe’schen Camera lucida, (A recent improvement of the Abbe Camera lucida.) [Post.] Bot. Centralbl., XII. (1882) pp. 211-2. ° », | Abbe’s Spectro-polarisator. (Abbe’s Spectro-polarizer.) [Post.] Bot, Centralbl., XL. (1882) pp. 284-6, Encavssé and Cantstz.—Mikrographoskop und Mikroskop zum Vergréssern und Photographiren zu gleicher Zeit. (Micrographoscope and Microscope for enlarging and photographing at the same time.) French Patent, No. 145,999, 23rd November, 1882 (1881 ?). Cf. Zeitschr. f. Instrumentenk., II. (1882) wrapper. “ F.R.M.S.”—Microscopy. Nelson’s Adapter. [Supra, p. 858. ] Engl. Mech.. XXXVI. (1882) p. 164. Grarr, T. 8. Up pe.—Letter descriptive of the Elmira Meeting of the American Society of Microscopists, The Microscope, II. (1882) pp. 123-33. See also infra, Stowell, C. H. and T. B, 3m 2 864 SUMMARY OF CURRENT RESEARCHES RELATING TO GounptacH, E.—A Simple Method of Determining the Angle of Aperture of Immersion Objectives. [Correction of the previous description at p. 142. Supra, p. 860.] Amer, Mon. Micr. Journ., III. (1882) p. 176. Hrroncocr, R.—The August Meetings. [Editorial on the Montreal meeting of the Amer. Assoc. Adv. Sci. and the Elmira meeting of the Amer. Soc. Micr.] Amer. Mon. Mier. Journ., III. (1882) pp. 176-7. - 34 The “ Jumbo” Microscope. [Brief comment. Supra, p. 850.] Amer. Mon. Micr. Journ., IIL. (1882) p. 178. 99 ss The Microspectroscope. [ Description of the Zeiss, Sorby-Browning and Sorby-Hilger instruments, with observations on the application of the spectroscope to the examina- tion of solutions or fluid compounds. | Amer, Mon. Micr. Journ., III. (1882) pp. 183-7 © figs.). 99 » Committee on Ruled Plates. [Supra, p. 861.] Amer. Mon. Micr. Journ., UII. (1882) pp. 197-8. Hoce, J.—The Microscope: its History, Construction, and Application; being a familiar introduction to the use of the instrument and the study of microscopical science. New ed. 8vo, London, 1883, xx. and 764 pp., 356 figs. and 8 pls. [Supra, p. 862.] Jrennines, J. H.—The Aperture Shutter. [Letter to the Editor in commendation, both in photo-micrography and ordinary microscopic work. “Some may say, ‘why not use special low-angle lenses which will give all requisite penetration?’ Simply because penetration is far from being the only desirable quality in an objective. Lenses that possess great penetration usually possess little else, and the loss of light entailed by their use is far greater than that experienced when using a wide-angle lens with the aperture shutter ” (!) ] North. Microscopist, 11. (1882) pp. 279-80. Jones, T. R.—Journal of the Royal Microscopical Society. [Review of Nos. 23-9.] Geol. Mag., TX. (1882) pp. 476-9. Kirton, J.—The sign x. [Reply to T. R. J., ante, p. 746. “ An inch is an inch, although its smaller divisions are not indicated.”] Sci.-Gossip, 1882, p. 232. _ Larrevx, P.—Manuel de Technique Microscopique, ou guide pratique pour l'étude et le maniement du Microscope. (Manual of Microscopical Technic, or practical guide for the study and management of the Microscope). 2nded. 8vyo, Paris, 1883, xi. and 477 pp., 176 figs. Maury, A. C.—Microphotography. [Reply as to finding the actinic focus of objectives, &c.] Engl. Mech., XXXVI. (1882) p. 257. “ Micro.”—A perture. [Criticism of J. L. W. Miles’ paper, infra. North. Microscopist, 11. (1882) pp. 281-2. Mikroskop, das, und seine Anwendung bei Untersuchung von Hopfen, Hefe &., nebst Beschreibung und Gebrauchs-Anweisung des Hefezaihlers. Hine Anleitung fiir Brauer u. Brenner. (The Microscope and its use in the observation of hops, yeast, &c., with description of and instructions for using the yeast-counter. A guide for Brewer and Distiller.) 8vo, Berlin, 1882, 20 pp., 1 pl. Mites, J. L. W.—The Optical Performances of Objectives—Aperture—The Aperture-shutter. [Paper read before Manchester Microscopical Society. ] North. Microscopist, II. (1882) pp. 284-91. + 3 Apertures and Amplification. [Reply to J. H, Jennings supra, and W. Stanley infra.] North, Microscopist, I1. (1882) pp. 319-20. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 865 Moors, A. J.—Camera Lucida. [‘‘ An ingenious modification of the ordinary camera lucida, consisting of a silvered disk, somewhat smaller in diameter than the pupil, centered upon a round cover-glass, which is attached to the eye-piece in the usual manner.” } The Microscope, II. (1882) pp. 130-1. Netson, E. M.—Quick acting Adapter for Microscopical Objectives (Ex- hibition of). [Supra, p. 858.] Engl. Mech., XXXVI. (1882) pp. 127-8. “One who was present.”—Aperture. [Criticism of J. L. W. Miles’ paper, supra. ] North, Microscopist, II. (1882) pp. 282-3. PELLETAN, J.—Microscope “Continental” du Dr. J. Pelletan, construit par E. Liitz. (Dr. J. Pelletan’s “ Continental’ Microscope, constructed by H. Liitz.) [Detailed description. ] Journ. de Microgr., V1. (1882) pp. 458-60. 9 » A propos du Microscope “Continental.” (On the “Conti- nental ” Microscope.) [Reply to C. Stodder, infra.] Journ. de Microgr., V1. (1882) pp. 532-3. ** Photo.”—A perture. [Criticism of J. L. W. Miles’ paper, supra. ] North. Microscopist, II. (1882) pp. 280-1. “ Prismatique.’—Object-glass Working. II. Engl. Mech., XXXVI. (1882) pp. 240-1. Row, F.—Photo-micrography, and the Relation of Photography to Micro- sco sh [Very general—26 lines. ] 1st Journ. and Rep. Braintree and Bocking Micr. and Nat. Hist. Club, 1882, pp. 14-15 (1 photo.). SurprrrpoTTrom, —.—The Aperture Shutter. [Letter to the Editor in commendation—Useful for “aiding in the pro- duction of that amount of penetration which is essential for the produc- tion of Micro-stereograms.”’] North, Microscopist, II. (1882) p. 282. SrantEy, W.—The Aperture Shutter. [Letter to the Editor in commendation—* Polycistina placed under 34-inch objective of 80° (!) and dark-ground illumination, with the condenser. The result was a glare, no definition, no penetration, but when the aperture shutter was applied an exceedingly good dark-ground was obtained with penetration sufficient to clearly define the whole of the interior markings of some of the larger cone-like forms.” ] North. Microscopist, 11. (1882) pp. 278-9. Srrvens, W. L.—The Physiology of Variable Apparent Magnification by the Microscope. Amer. Mon. Micr. Journ., III. (1882) pp. 188-91. Stopper, C.—A propos du Microscope “ Continental.’’ (On the “ Continental ” Microscope.) [Letter to Dr. Pelletan commending the size of the new instrument as compared with the ordinary French and German models, and criticizing the length of the rackwork, the fine movement, &c. ] Journ, de Microgr., VI. (1882) pp. 531-2. See also supra, Pelletan, J. SrowEtu, C. H.—Notes on the Elmira Meeting of the American Society of Microscopists and the new President. — The Microscope, II. (1882) pp. 137, 138-9, See also supra, Graff, T. 8. Up de, and infra, Stowell, T. B. StowEtt, T. B.—[Report of the Elmira Meeting of “ the American Society of Microscopists, containing the President’s Address in full.” (The address is in full abstract. ] The Microscope, II. (1882) pp. 97-106. See also supra, Graff, T. S. Up de, and Stowell, C. H. 866 SUMMARY OF CURRENT RESEARCHES RELATING TO Taytor, G. C.—New Mechanical Lamp. [“ A modification of the Hitchcock lamp, in which the burner is brought very low upon the table, while the intensity of the light is regulated by a movable diaphragm which increases or curtails the volume of air admitted to the fan. A practical test of the light in resolying fine lines proved its superiority over all lamps yet devised.”] The Microscope, 11. (1882) p. 128. Trutat, E.—Traité élémentaire du Microscope. le Partie. Le Microscope et son emploi. (Hlementary Treatise on the Microscope. Part I. The Microscope and its employment.) xvi. and 322 pp., 171 figs., and 1 phototype. 8vo, Paris, 1883 (1882). Warp, R. H.—Report of Committee on Eye-pieces. [Supra, p. 861.] Amer. Mon. Micr. Journ., 11. (1882) p. 175. Cf. also p. 171. a a Microscopy at the American Association. [Note on the first meeting of the new section of Histology and Micro- scopy and Dr. Carpenter’s visit. | Amer. Natural., XVI. (1882) p. 931. Wueeer, E.—Lecture on Light, the Microscope, &c. 1st Jown. & Rep. Braintree §¢ Bocking Micr. § Nat. Hist. Club, 1882, pp. 12-14. B. Collecting, Mounting and Examining Objects, &c. Methods of Microscopical Research in use in the Zoological Station at Naples.*—Dr. P. Mayer gives an account of the methods employed at the Naples Zoological Station for preserving, staining, and mounting objects, some of which have not previously been published. Although they are only mentioned in connection with marine forms they are in many cases applicable also to fresh-water organisms, insects, &c. J. Preservative Fiuips.—Killing, hardening, and preserving are three kinds of work, requiring for their accomplishment sometimes only a single preservative fluid, but in most cases two, three, or even more. Asthe same fluid often does the work of killing and hardening, and sometimes of preserving too, it is impossible to divide them into three classes corresponding to the kinds of work, except by repeating many of them twice, and some of them three times. While itis there- fore more convenient to include them all under “ preservative fluids,” as Dr. Mayer has done, it is none the less important to remember what * MT. Zool. Stat. Neapel, ii. (1880) pp. 1-27. We ought long since to have printed a translation of this paper, but in consequence of a succession of accidents we have been prevented doing so, notwithstanding that we had a complete translation made of it soon after it appeared. The abstract we now give is that (with slight alterations) of C. O. Whitman in Amer. Natural., xvi. (1882) pp. 697-706, who says “I have added the methods of Dr. Giesbrecht, Dr, Andres (infra), and some others who have worked in the zoological station. Dr. Mayer has further placed at my disposal such improvements and alterations as he has been able to make since the publication of his paper. I am also deeply indebted to Dr. Mayer for advice and generous assistance, for which I wish here to give ex- pression to my most sincere thanks and grateful appreciation. I am still further indebted to Dr. Hisig, Dr. Lang, Dr. Andres, Dr. Giesbrecht, Professor Weismann, and Professor Dohrn, all of whom I have had occasion to consult with reference to matter contained in this paper.’ Mr. G. Brook, junr., also rendered a very useful service to microscopists by publishing a summary in ‘ Naturalist,’ vi. and vii. (1881), parts of which are embodied in the text. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 867 kind or kinds of work each fluid is expected to accomplish. Kleinen- berg’s picro-sulphuric acid, for instance, now so much used in the Naples Aquarium, is not a hardening fluid. It serves for killing, and thus prepares for subsequent hardening. 1. Kleinenberg’s Picro-sulphuric acid * :— Picric acid (cold saturated solution in distilled water) .. .. .. . +». 100 volumes Sulphuric acid (concentrated) ..., 2 ” Filter the mixture, and dilute it with three times its bulk of water (or for Arthropoda undiluted), finally add as much creosote (made from beech-wood tar) as will mix. Objects are left in the fluid three, four, or more hours ; t and are then, in order to harden and remove the acid, transferred to 70 per cent. alcohol, where they may remain 5 to6 hours. They are next placed in 90 per cent. alcohol, which must be changed at intervals until the yellow tint has wholly disappeared. The advantages of this fluid are, that it kills quickly, by taking the place of the water of the tissues; that it frees the object from sea- water and the salts contained in it, and that having done its work it may be wholly replaced by alcohol. In this latter fact lies the superiority of the fluid over osmic and chromic solutions, all of which produce inorganic precipitates and thus leave the tissues in a condition un- favourable to staining. Picro-sulphuric acid does not, like chromic solutions, harden the object, but simply kills the cells. As this fluid penetrates thick chitine with difficulty, it is necessary, in order to obtain good preparations of larger Isopoda, insects, &c., to cut open the body with the scissors and fill the body-cavity with the liquid by means of a pipette. In larger objects care should be taken to loosen the internal organs so that the fluid may find easy access to all parts. The fluid should be applied as soon as the body is opened, so that the blood may not have time to coagulate and thus bind the organs together. A large quantity of the fluid should be used (especially when objects with large internal cavities have to be prepared whole), and it must be changed as often as it becomes turbid. The same rule holds good in the use of all preservative fluids. It is well also, especially with larger objects, to give the fluid an occasional stir- ring up. In order to avoid shrinkage in removing small and tender objects * Quart. Journ. Micr. Sci., xix. (1879) pp. 208-9. See this Journal, ii. (1879) . 461. + Dr. Mayer prepares the fluid as follows :—Water (distilled), 100 vols. ; sulphuric acid, 2 vols.; picrie acid as much as will dissolve. Filter and dilute as above. No creosote is used. t Dr. Mayer’s own remarks are:—How long objects should remain in the acid depends of course upon their nature. Usually a few hours is sufficient, but for larger objects and those containing a large percentage of water a longer time is necessary. In some cases a whole day does not produce any injurious effect. 868 SUMMARY OF CURRENT RESEARCHES RELATING TO from the acid to the alcohol, it is advisable to take them up by means of a pipette or spatula, so that a few drops of the acid may be trans- ferred along with them. The objects, sinking quickly to the bottom, remain thus for a short time in the medium with which they are saturated, and are not brought so suddenly into contact with the alcohol. In a few minutes the diffusion is finished ; and they may then be placed in a fresh quantity of alcohol, which must be shaken up frequently and renewed from time to time until the acid has been entirely removed. The sulphuric acid contained in this fluid causes connective tissue to swell, and this fact should be borne in mind in its use with verte- brates. ‘To avoid this difficulty Kleinenberg has recommended the addition of a few drops of creosote, made from beech-wood tar, to the acid. According to Dr. Mayer’s experience, however, the addition of creosote makes no perceptible difference in the action of the fluid. Professor Emery finds the process very useful for embryos of vertebrates and for fishes, but they should not be allowed to remain in the acid more than three or four hours. Although the method is considerably the best for preserving Crustacea as a rule, it will not do for the parasitic species, in which it produces swellings, dissolu- tion of parts of the tissues, &c. 2. Picro-nitric or Picro-hydrochloric acid.—Kleinenberg’s fluid must not be used with objects (e.g. Echinoderms) possessing cal- careous parts which it is desired to preserve, for it dissolves carbonate of lime and throws it down as crystals of gypsum in the tissues. For such objects picro-hydrochloric or picro-nitric acid may be used, prepared as follows :— Water ai eo bee ee ee Nitric acid (25 per cent. N,O;) HI 5 [or hydrochloric acid (25 per cent. HCl) 8 Picric acid as much as will dissolve.* 100 volumes. bh) ad Picro-nitric acid also dissolves carbonate of lime, but it holds it in solution, and thus the formation of crystals of gypsum is avoided. In the presence of much carbonate of lime, the rapid production of carbonic acid is liable to result in mechanical injury of the tissues, hence in many cases chromic acid is preferable to picro-nitric acid. Picro-nitric acid is, in most respects, an excellent preservative medium, and as a rule will be found to be a good alternative in those cases where picro-sulphuric acid fails to give satisfactory results. Dr. Mayer commends it very strongly, and states that with eggs containing a large amount of yolk material, like those of Palinurus, it gives better results than nitric, picric, or picro-sulphuric acid. It is not so readily removed from objects as picro-sulphuric acid, and for this reason the latter acid would be used wherever it gives equally good preparations. * This mixture is used undiluted. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 869 3. Alcohol—In the preparation of animals or parts of animals for museums or histological study, it is well known that the chief difficulties are met in the process of killing. Alcohol, as com- monly used for this purpose by collectors, has little more than its convenience to recommend it. Dr. Mayer calls attention to the following disadvantages attending its use in the case of marine animals :— (1) In thick-walled animals, particularly those provided with chitinous envelopes, alcohol causes a more or less strong maceration of the internal parts, which often ends in putrefaction. (2) In the case of smaller Crustacea, e. g. Amphipods and Isopods, it gives rise to precipitates in the body-fluids, and thus solders the organs together in such a manner as often to defy separation even by experienced hands. (3) It fixes most of the salts of the water adhering to the surface of marine animals, and thus a crust is formed which prevents the penetration of the fluid to the interior.* (4) This crust also prevents the action of staining fluids, except aqueous solutions, by which it would be again dissolved. Notwithstanding these drawbacks, alcohol is still regarded at the Naples Aquarium as an excellent fluid for killing many animals designed for preservation in museums or for histological work. In many cases the unsatisfactory results obtained are to be attributed not to the alcohol per se, but to the method of using it. Most of the foregoing objections do not, as Dr. Mayer expressly states, apply to fresh-water animals; and Dr. Eisig informs Mr. Whitman that he has no better method of killing marine annelids than with alcohol. Judging from the preparations which were shown him, and which were all beautifully stained with borax carmine, Dr. Hisig’s mode of treatment must be pronounced very successful. The process is extremely simple; a few drops of alcohol are put into a vessel which contains the annelid in its native element, the sea-water; this is repeated at short intervals until death ensues. After the animal has been thus slowly killed, it may be passed through the different grades of alcohol in the ordinary way, or through other preservative fluids. Objects killed in this manner show no trace of the external crust of precipitates which arises where stronger grades of alcohol are first used. The action of the alcohol is thus moderated, and the animal, dying slowly, remains extended and in such a supple con- dition that it can easily be placed in any desired position. The violent shock given to animals when thrown alive into alcohol of 40 per cent. to 60 per cent., giving rise to wrinkles, folds and distortions of every kind, is thus avoided, together with its bad effects. ; 4, Acid Alcohol.—In order to avoid the bad effects of alcohol, * Dr. Mayer first noticed this in objects stained with Kleinenberg’s hema- toxylin, and afterwards in the use of cochineal, where a grey-green precipitate is sometimes produced which renders the preparation worthless. Such results may be avoided by first soaking the objects a few hours in acid alcohol (1-10 parts hydrochloric acid to 100 parts 70 per cent. alcohol). 870 SUMMARY OF CURRENT RESEARCHES RELATING TO such as precipitates, maceration, &c., Dr. Mayer recommends acid alcohol— 97 volumes 70 per cent. or 90 per cent. alcohol, 3 » hydrochloric acid, for larger objects, particularly if they are designed for preservation in museums. The fluid should be frequently shaken up, and the object only allowed to remain until thoroughly saturated, then trans- ferred to pure 70 per cent. or 90 per cent. alcohol, which should be changed a few times in order to remove all traces of the acid. For small and tender objects, acid alcohol, although preferable to pure alcohol, gives less satisfactory results than picro-sulphurie acid. Acid alcohol as above prepared loses its original qualities after standing some time, as ether compounds are gradually formed at the expense of the acid. 5. Boiling Alcohol.In some cases among the Arthropods, Dr. Mayer has found it difficult to kill immediately by any of the ordinary means, and for such cases recommends boiling absolute aleohol, which kills instantly. For Tracheata this is often the only means by which the dermal tissues can be well preserved, as cold alcohol pene- trates too slowly. - 6. Osmic Acid.—Dr. Mayer employs osmic acid as a staining medium for the hairs, bristles, &c., of the dermal skeleton of Arthro- pods. The lustre of Sapphirina is preserved by this acid,* and according to Emery, the colour of the red and the yellow fatty pig- ments of fishes. Van Beneden found osmic acid the best preservative fluid for the Dicyemide, and Mr. Whitman’s experience leads to the same conclusion. Although Dr. Mayer seldom uses this medium where histological details are required, he observes that in those classes of animals whose bodies are easily penetrated with watery fluids, osmic acid is seldom to be dispensed with. Bleaching.—It often happens that objects treated with osmic acid continue to blacken, after removal from the acid, until they are entirely worthless, and such results are even more annoying than the difficulties in the way of staining. It has been said that the blacken- ing process can be arrested by certain staining media, but if is certain that picro-carmine will not always do this, as some of Mr. Whitman’s preparations of Dicyemide show. It is therefore a very important step which Dr. Mayer has taken in finding a method of restoring such objects. The method { is as follows :—The objects are placed in 70 per cent. or 90 per cent. alcohol, and crystals of potassic chlorate (KC10,) shaken into the liquid until the bottom of the vessel is covered; then a few drops of concentrated hydrochloric § acid are * See corrosive sublimate, p. 872. + One of the best objects for testing methods is found in Phronima sedentaria, Here the cells and nuclei are so sharply defined that they can be seen in the living animal, and so the effect of a preservative fluid can be easily studied. t A slightly modified form of the method originally given in Arch. f, Anat. u. Physiol. (Du Bois Reymond and Reichert) 1874, p. 321, § Nitric acid may be used instead of HCl. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 871 added with a pipette, and as soon as chlorine (easily recognized by its greenish-yellow colour) begins to be liberated, the whole gently shaken. As soonas the bleaching is finished the objects are removed to pure alcohol. By this method Dr. Mayer has been able in half a day to restore large Pelagia, Carinaria, Rhizostoma, &c. Small objects generally require a shorter time and less acid. The process can be greatly accelerated by heating on a water-bath. Using Sapphirina as a test-object, Dr. Mayer found that the lustre which characterizes the living animal entirely disappeared by the bleaching process. As this lustre, which has its seat in the epidermis, depends on the interference of light, it is evident that the cells had undergone some change, but a change so slight that the tissues could hardly be said to have been injured for histological purposes ; besides, the removal of the osmic acid leaves the animal in a good condition for staining. Dr. Mayer’s experience with Sapphirina appears to support him in the following conclusions in regard to the nature of the action of osmic acid, viz. that the hardening effect of the acid is due to the formation of inorganic precipitates within the tissues. This is made evident by the fact that the animal becomes soft and flexible as soon as these precipitates are removed by bleaching. This method of bleaching has been used by Dr. Mayer for removing natural pigment. Alcoholic preparations of the eye of Mysis, for instance, can be fully bleached im toto, but with better success by operating with single sections. To avoid swelling, which is apt to arise by the use of aqueous fluids, staining media of an alcoholic nature should be used. 7. Chromic Acid.—_Chromic solutions have, in common with osmic acid, the peculiarity of hardening by virtue of the chemical combina- tions which they form with cell-substances, and all the consequent disadvantages with respect to staining. The use of chromic acid in the Zoological Station of Naples may be said to have been largely superseded by picro-sulphuric acid, corrosive sublimate, and Merkel’s fluid, for it is now seldom used except in combination with other fluids.* It is sometimes mixed with Kleinenberg’s fluid, for example, when a higher degree of hardening is required than can be obtained by the use of the latter fluid alone. It is a common error to use too strong solutions of chromic acid, and to allow them to act too long. Good results are in some cases obtained when the objects are treated with a weak solution (}—} per cent.) and removed soon after they are completely dead. 8. Merkel’s Fluid.— Platinum chloride dissolved in water .. .. .. 1:400 Chromic acid = 55 oo et” ee eee * Dr. W. Pfitzner (Morphol. Jahrb., vii. (1882) p. 731) has recently made use of chromic acid followed by (1) osmic acid, or by (2) chloride of gold, formic acid and safranin (or hematoxylin) for the demonstration of nerve-terminations. Flemming believes that chromic acid is one of the most reliable fixing re- agents for the karyokinetic figures, and has proved that objects hardened in this acid can be beautifully and durably stained, ante, p. 715. 872 SUMMARY OF CURRENT RESEARCHES RELATING TO Professor Merkel,* who employed a mixture of these two solutions in equal parts for the retina, states that he allowed from three to four days for the action of the fluid. Dr. Hisig has used this fluid with great success in preparing the delicate lateral organs of the Capitellide for sections, and recommends it strongly for other annelids. Dr. Hisig allows objects to remain 3-5 hours in the fluid, then transfers to 70 per cent. alcohol. With small leeches Mr. Whitman has found one hour quite sufficient, and transfer to 50 per cent. alcohol. 9. Corrosive Sublimate—Prompted by a statement found in an old paper by EH. Blanchard,t Dr. Lang began experimenting with corrosive sublimate as a medium for killing marine Planarians, and his marked success led him and others to employ the same with other animals. In most cases Dr. Lang now uses a saturated solution of corrosive sublimate in water. A saturated solution in picro-sulphuric acid, which in some cases gives better results if a little acetic acid (5 per cent. or less) is added, is also used.{ Blanchard’s mode of treatment was to mix a quantity of the aqueous solution with the sea- water, and thus poison the animals. Dr. Lang, on the contrary, removes the sea-water so far as possible before applying the solution. With Planarians he proceeds in the following manner :— The animal is laid on its back and the water removed with a pipette, the solution being then poured over it, it dies quickly and remains fully extended. After half an hour it is washed by placing it in water and changing the water several times during thirty minutes. It is next passed through 50 per cent., 70 per cent., 90 per cent., and 100 per cent. alcohol. In two days it is fully hardened, and should then be stained and imbedded in paraffin as early as possible, as it is liable to become brittle if left long in alcohol. The time required by the corrosive sublimate varies with different objects, according to size and the character of the tissues. As a general rule, it may be said that objects should be removed from the fluid as soon as they have become thoroughly saturated by it. In. order to kill more quickly than can sometimes be done at the ordinary tempera- ture, the solution is heated, and in very difficult cases may be used boiling. Corrosive sublimate has been used with success by Dr. Lang and others in the following cases :—Hydroids, Corals, Nemertines, Gephy- reans, Balanoglossus, Echinoderms, Sagitta, Annelids, Rhabdoccela, Dendroceela, Cestodes, Trematodes, embryos and adult tissues of Vertebrates and, according to Mayer and Giesbrecht, Crustacea with thin chitinous envelopes, e.g. Sapphirina, Copepods and larvee of Decapods. With the Arthropoda good results have not been ob- tained. * ‘Ueber die Macula lutea des Menschen,’ &., Leipzig, 1870, p. 19. + Ann. Sci. Nat. Zool., viii. (1874) p. 247. + These solutions are given in Zoolog. Anzeiger, ii. (1879) p. 46. The original solution (Zoolog. Anzeiger, i. (1878) pp. 14-15, this Journal, i. (1878) p. 256) now little used, stood thus :—Distilled water, 100 parts; common salt, 6-10 parts ; acetic acid, 5-8 parts; corrosive sublimate, 3-12 parts; alum (in some cases) $ part, ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 873 The two great advantages of Dr. Lang’s method are (1) that animals so treated are easily stained, and (2) they are killed so quickly that they are left, in most cases, in a fully extended condi- tion. Hot corrosive sublimate kills leeches so instantaneously that they often remain in the attitude assumed the moment before the fluid is poured over them. The colour, however, is not so well preserved as when killed with alcohol, or even with weak chromic acid. It should be remembered that objects lying in a solution of corro- sive sublimate must not be touched with iron or steel instruments; wood, glass, or platinum may be used. II. Srarminc.—It has gradually become a settled custom in the Zoological Station to mount microscopical preparations in balsam wherever this can be successfully done; and to avoid, as much as possible, the use of aqueous media, both in mounting and staining. The disadvantages often arising from the use of these media in stain- ing alcoholic preparations include the tearing asunder of fragile tissues caused by the violent osmosis set up on transferring an object from alcohol to an aqueous solution; swelling, the effects of which cannot always be fully obliterated by again transferring to alcohol ; and maceration, which is liable to result where objects are left for a con- siderable time in the staining liquid (as Beale’s carmine). These may all be avoided by using alcoholic solutions. Objects once successfully hardened may be left in such solutions for any required time, and when sufficiently stained, be washed in alcohol of a corresponding strength, and then passed through the higher grades without being exposed to water from first to last. Asa rule, alcoholic dyes work quickly, and give far more satisfactory results than can be obtained with other media. They penetrate objects more readily, and thus give a more uniform colouring where objects are immersed in toto. Even chitinous envelopes are seldom able to prevent the action of these fluids. It is not, however, to be denied that non-alcoholic dyes may often do excellent work, and, in certain cases, even better than can be other- wise obtained. In the case of the Turbellaria, Dr. Lang has found picro-carmine to be one of the best staining agents, and this has been Mr. Whitman’s experience with Dicyemide. As Dr. Mayer has re- marked, the swelling caused by aqueous staining fluids is not always an evil, but precisely what is required by some objects after particular methods of treatment. From experiments recently made, Dr. Mayer has found that dyes containing a high percentage of alcohol, stain more diffusely than those of weaker grades, from which he infers that strong alcohol robs, to a certain extent, the tissues of their selective power, and renders them more or less equally receptive of colouring matter. 1. Kleinenberg’s Heematoxylin.*—1. To a saturated solution of chloride of calcium f in 70 per cent. alcohol, add a little alum and filter. * May be used after all hardening fluids. + Chloride of calcium, according to Kleinenberg, has no other use than to strengthen the osmotic action between the hematoxylin solution and the alcohol contained in the tissues. As chloride of calcium and alum give a precipitate of gypsum, it would probably be better to use chloride of aluminium. 874 SUMMARY OF CURRENT RESEARCHES RELATING TO 2. One volume of No.1 mixed with 6 to 8 volumes of 70 per cent. alcohol. ; 8. At time of using pour into No. 2 as many drops of a concen- trated solution of crystallized hematoxylin in absolute alcohol as suffice to give the required depth of colour. A good solution should be violet inclining a little to blue. The red tinge that arises after the fluid has stood for some time, indicates that it has become slightly acid, in which condition it is unfit for use. To restore its proper colour, it is only necessary to open a bottle of ammonia over the mouth of the bottle holding the hematoxylin in such a manner that a very small quantity of the gas will mix with the fluid. If too much ammonia gas be added, a precipitate is produced which spoils the fiuid. If the colour appears too strong, the fluid may be diluted with solution No. 1. Before immersing objects in this fluid, great care should be taken to free them from the least trace of acid by frequently changing the alcohol. If this is not done thoroughly, the acid left in the prepara- tion will sooner or later cause the colour to fade; and such results have led to the erroneous conclusion that hematoxylin will not give durable preparations. Dr. Mayer has found that the fading is entirely due to the presence of acid, and that with proper precautions the staining is permanent. Small objects are best stained in a weak solution, which colours more slowly but with greater clearness than stronger solutions. After staining, Kleinenberg transfers objects to 90 per cent. alcohol. In case of over-staining, the colour may be partly removed by adding a little oxalic acid or hydrochloric acid (4 per cent. or less) to the alcohol containing the objects. The acidulated alcohol is allowed to work until the colour is slightly reddened. On transferring to pure alcohol the colour passes again into a permanent blue-violet. 2. Mayer's Cochineal Tincture—This medium is very similar in most respects to hematoxylin, and is made by soaking 1 gramme powdered cochineal in 8-10 cem. 70 per cent. alcohol for several days, and then filtering. The clear deep red fluid thus prepared may, like hematoxylin, be used in all cases where it is desirable to stain with an alcoholic solu- tion, and will be found particularly useful for objects that, by reason of the thickness of the walls or other peculiarities, are not easily pene- trated by the ordinary aqueous solutions of carmine. It is particularly suited for the Arthropoda, whose chitine only allows the dye to penetrate with difficulty. It is necessary, before immersing larger objects in this fluid, to leave them a short time in 70 per cent. alcohol, otherwise there may be a precipitate. The time required for staining will vary from a few minutes to even days, according to the nature and size of the object. For small objects, such as very thin sections, minute worms, Protozoa, the lower Arthropoda, &c., an immersion of a quarter of an hour, sometimes even less, is usually sufficient. With larger objects re- quiring considerable time, it is important to use a large quantity of the fluid, otherwise the amount of colouring stuff in solution might ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 875 not suffice to give the proper depth of colour. Small and delicate objects, on the other hand, may be most successfully treated with a solution which has been diluted with 70 per cent. alcohol, or one which has been weakened by previous use. It is always necessary to free the tissues, after staining, from the surplus dye; and this may be done by washing in 70 per cent. alcohol, which must be changed until it shows no colour. This process requires, for larger objects, con- siderable time and alcohol, but may be hastened by using the alcohol slightly warm. The colour ultimately assumed by objects treated with cochineal tincture varies much, and depends partly on the reaction of the tissues themselves, partly on, the presence or absence of certain salts. It is certainly one of the best recommendations of this staining agent that varying with the nature of the object and its mode of treatment both ’ before and after staining, it gives such an extraordinary diversity of results. On account of the great variety of substances contained in the dried dye-stuff, it is evident that the composition of the tincture must vary according to the strength of the alcohol employed as a solvent. Solutions in 90 per cent. or 100 per cent. alcohol have a light red colour, and stain too diffusely to have any practical value. The weaker the alcohol the stronger the tincture, and the stronger the alcohol the more easily it penetrates objects; the grade of alcohol may therefore be selected with reference to two points, depth of colour and readiness of penetration; 70 per cent. or 60 per cent. is recom- mended by Dr. Mayer as combining both these qualities in a very favourable degree. It is important to remember that whatever be the strength of the solution, a precipitate will always be produced if an alcohol of a different grade, whether higher or lower, be mixed with it. It is evident, then, that a tincture of any given strength contains substances that are insoluble in any other grade of alcohol, and this explains why superfluous colouring matter can only be removed from objects by the aid of alcohol of precisely the same degree as that of the tincture. Over-staining, which seldom occurs, may be easily corrected by the aid of acid alcohol ({'5 per cent. hydrochloric acid, or 1 per cent. acetic acid). Acid makes the tincture lighter, more yellowish-red, while the addition of ammonia and other caustic alkalies changes it to deep purple. Still more important is the fact that salts soluble in alcohol give a blue-grey, green-grey, or blue-black precipitate. For example, if a piece of cloth that has been dyed in cochineal and washed be treated with an alcoholic solution of a ferric or a calcic salt, it will assume a more or less deep blue colour. As the salts present in the living organism are seldom, if ever, fully removed by preservative fluids, but in some cases even increased, it will often happen that an object, though put in the red fluid, comes out blue, precisely as when stained with hematoxylin. Such a result cannot, however, be obtained where the tissue is in the presence of acids, or free from inorganic salts; under these conditions the colour is always red. It is not possible, therefore, to know what colour an object will ultimately present. 876 SUMMARY OF CURRENT RESEARCHES RELATING TO Usually, all Crustacea with thick chitinous parts are stained red, and most other animals blue; so that, for instance, the Vorticellide, which are parasitic on the Amphipoda, can be at once recognized as foreign bodies. Very often the different tissues of one and the same object present unlike colours. In the embryos of Lumbricus, Kleinen- berg found the walls of the blood-vessels red, their contents dark- blue. Glandular tissues, or their contents, are frequently stained grey-green, and on this account are easily recognizable. Objects when previously treated with chromic or picric solutions, or with alcohol, usually stain without difficulty; but osmic acid preparations should be bleached before staining. Cochineal does not colour so intensely as hematoxylin, and hence the latter often gives more satisfactory results in the case of large objects stained in toto. As before pointed out, alcohol causes the salts contained in sea- water to be precipitated, thus forming a crust on the exterior of the animal, which interferes with the staining process. It is therefore necessary to treat marine animals that have been preserved in strong alcohol, with acid alcohol (1-10 parts hydrochloric acid to 1000 parts 70 per cent. alcohol), and then carefully wash in pure 70 per cent. alcohol before staining with cochineal. 3. Carmine and Picrocarmine——Aqueous solutions of staining media are generally only used when alcoholic cannot be employed. The interpretation of the results obtained by carmine staining is not always satisfactory. For instance, in his work on the nervous system of Aquilla, Bellona describes the peculiar crescent-like structures in the ganglion cells. Dr. Mayer is of opinion that these are entirely artificial productions, and owe their origin to the carmine (Beale’s) solution in which they were stained, for with careful preparation they do not appear. Picrocarmine is more certain in its results, and in some cases will give better specimens than can be obtained by any other medium. In commerce it often contains too much picric acid, and it is better to prepare it oneself in the following manner :-— To a mixture of powdered carmine (2 g.) with water (25 ccm.), while heating over a water-bath, add sufficient ammonia to dissolve the carmine. The solution may then be left open for a few weeks (Mayer) in order that the ammonia may evaporate; or the evaporation may be accelerated by heating (Hoyer). So long as any ammonia remains, large bubbles will form while boiling, but as soon as the free ammonia has been expelled, the bubbles will be small and the colour of the fluid begin to be a little lighter. It is then allowed to cool, and filtered. To the filtered solution is added a concentrated aqueous solution of picric acid (about four volumes of the acid to one of the carmine solution). The addition of the acid should cease before a precipitate begins to form. . In order to protect this fluid against changes attributed to bacteria by Hoyer,* Dr. Mayer places a small crystal of thymol in the con- * Hoyer, “ Beitr. z. histolog. Technik.,” Biol. Centralbl., ii, (1882) pp. 17-19. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 877 taining bottle; Hoyer uses choral-hydrate (1 per cent. or more) for the same purpose.* 4, Acetic Acid Carmine.t—Pulverized carmine added to a small quantity of boiling acetic acid (45 per cent.) until no more will dissolve; filtered and diluted to about 1 per cent. for use. Flemming used the concentrated solution. 5. Grenacher’s Carmine Solutions.{ — (i.) Alum Carmine. — An aqueous solution of alum (1-5 per cent., or any degree of concentra- tion) boiled with 2-1 per cent. powdered carmine for 10-20 minutes ; allowed to cool, then filtered. With the addition of a little carbolic acid the fluid will keep for years. It colours quickly, and nuclei more strongly than other parts. Objects washed in water after staining. (i1.) Acid Borax Carmine.—a. An aqueous solution of borax (1-2 per cent.) and carmine (}—} per cent.) heated till the carmine is dissolved. b. Acetic acid added by drops to solution a, while shaking, until the colour is about the same as that of Beale’s carmine. ce. Solution 6 left standing twenty-four hours, then turned off and filtered. This solution, which is a modification of Schweigger-Seidel’s acid carmine, is not recommended for colouring in toto. It colours sections in 3-3 minutes diffusely, and hence, after washing in water, they are placed for a few minutes in alcohol (50 or 70 per cent.) to which a drop of hydrochloric acid has been added; then transferred to pure alcohol. (iii.) Borax Carmine.§—a. An aqueous solution of borax (4 per cent.) and carmine, heated till the carmine is dissolved. b. Solution a mixed with 70 per cent. alcohol in equal parts, left standing twenty-four hours and filtered. ' This fluid may be used for colouring objects in toto. After stain- ing, the objects are to be washed in 35 per cent. alcohol, to which a little hydrochloric acid has been added (4-6 drops to 100 cem.), and allowed to remain here until the colour has been sufficiently removed. They are next passed through successively higher grades of alcohol for hardening. (iv.) Alcohol Carmine.—A teaspoonful of carmine dissolved, by heating about ten minutes, in 50 cem. of 60-80 per cent. alcohol, to which 3-4 drops of hydrochloric acid have been added, then filtered. * Dr. Lang’s picro-carmine and eosin method for Planarians, see this Journal, ii. (1879) p. 163, is also referred to, Dr. Mayer does not expect any particular advantage from its application to Arthropods. t+ Schneider, Zool. Anzeig., 1880, p. 254. $ Grenacher, “ Einige Notizen z. Tinctionstechnik,” Arch. f. Mikr. Anat., xvi. (1879) p. 463. None of these solutions should be used where calcareous parts are to be preserved. § Dr. Mayer prepares, for some purposes, borax carmine of 50, 60, or 70 per cent. That of 70 per cent. contains little carmine, but is well adapted to staining delicate objects that would suffer if exposed to weaker solutions. Boiling alcohol a per cent. or 60 per cent.) dissolves about 1 per cent carmine and 1 per cent. orax. Ser. 2.—Vol. II. 3 N 878 SUMMARY OF CURRENT RESEARCHES RELATING TO Objects coloured in this fluid should not be washed in water, but in alcohol of a grade corresponding to that of the solution. For diluting alcoholic solutions of carmine, alcohol of the same strength must always be used. 6. Aniline Dyes.—As a rule, aniline colours and the many others obtained recently from tar by chemical processes, cannot be used for staining objects in toto, and are therefore not much employed in the Zoological Station. In very small objects and sections already cut, very excellent results can be obtained by the methods developed by Bottcher,* Hermann,t Flemming{ and others; for here diffuse staining may generally be avoided by first over-staining and then withdrawing the colour to any desired extent by means of alcohol. But to obtain satisfactory results, the sections must be thin enough to allow uniformity of action both to the colouring and the decolouring agent. It is evident that the process cannot be similarly controlled in larger objects, particularly where a dye is used, which, like most of those under consideration, is quickly extracted by alcohol, for in this case the colour would be removed from the superficial layers more rapidly than from the deeper ones, so that a uniform precision of colour would be impossible. In this respect, a. Bismarck-brown forms an exception. The preparation of this dye, introduced by Weigert,§ is extremely simple:— A saturated solution is made by dissolving the powder in boiling water or weak alcohol, or, according to Mayer, in 70 per cent. alcohol.|| The solution should be used undiluted, and requires to be filtered from time to time. It colours very quickly objects hardened in alcohol or chromie acid. b. Safranin.—1 part safranin dissolved in 100 parts of absolute alcohol ; after a few days 200 parts of distilled water is added. Dr. Pfitzner,f from whom the above formula is taken, reeommends this solution as one of the best for staining nuclei. It is cheap, easily prepared, acts quickly, and stains only the nuclei. It works best with chromic acid preparations, from which the acid has been removed as much as possible. Unless therefore it is desired to differentiate membranes or display the various stages of ossification this group may be dispensed with. III. Insectine.—Professor Emery, who has lately studied the methods of injection, recommends the following :— a. For injection of thick carmine he follows the prescription of Ranvier, in his ‘ Traité dhistologie technique,’ but neutralizes the mass in a more simple way. Acetic acid is added by drops until the * Bottcher, Mull. Archiv, 1869, p. 373. Virchow’s Archiv, xl. p. 302. + Hermann. Communicated to the Naturforscherversammlung in Graz, 1875. Tagblatt, p. 105, { Flemming, Arch. f. Mikr, Anat. xiii. p. 702; xvi. p. 302; xviii. p. 151; xix. pp. 317, 742; xx. p. 1. § Arch. f. Mikr. Anat., xv. (1878) p. 258. || According to Flemming, it may also be dissolved in dilute acetic acid. S| Morph. Jahrb., vi. pp. 478-80, and vii. p. 291. ZOOLOGY AND BOTANY, MIOROSOOPY, ETC. 879 smell of the ammonia becomes very faint. The reaction of the vapour is then tried with litmus paper. Sufficient acid has been added when the litmus paper begins to get red. Often, on stirring, the alkaline reaction will return,but this must beremoved with another drop of acetic acid. In use it will be found that with a neutral or slightly acid mass, a diffusion of the medium through the cell-walls is scarcely likely to oceur. b. As a cold fluid mass, Emery recommends a 10 per cent. carmine solution prepared with ammonia, to which, while continually stirring, acetic acid is added until the carmine begins to be precipitated, and the liquid has a blood-red colour. The clear liquid only must be used, and after injection, the objects must be at once placed in strong alcohol, to fix the carmine. c. For injecting the capillaries, good results are often obtained by gradually mixing 10 per cent. carmine solution with acetic acid, until part of the carmine is precipitated. The solution must be shaken shortly before use, only allowing it to settle for a few minutes, so that the coarser grains do not get into the syringe. In injections from the arteries a considerable quantity of fine sediment remains in the capillaries, while only a light fluid enters the veins. Thus the veins can easily be distinguished from the arteries, which are dyed dark red. IV. Movuntine.—The great object aimed at, in preparing per- manent preparations for the Microscope, is to entirely get rid of the water in the tissues of the object, and supplant it by a preservative medium. Hence, at Naples the aqueous mounting media such as glycerine, glycerine jelly, acetate of potash, &c., are in little favour. After the water has been forced from the object and supplanted by alcohol, the process is usually completed by passing through oil of cloves, and mounting in balsam. Usually there is little trouble with this method. The oil of cloves, or other similar oil, is slightly heated, and as a rule it will penetrate the tissues without trouble. With larger objects, however, and particularly those with thin but not easily permeable walls, the alcohol will often leave before the oil can enter, and there will be a collapse of the walls. Creosote has been used to prevent this shrinking, but it appears to render no permanent good. Dr. Mayer meets the difficulty in the larger objects by making an insertion with a fine pair of scissors in an unimportant part of the body-cavity, so as to allow the oil to entcr atonce. This answers very well, and can be used with very small objects, such as Auricularia and other larve, if a fine flattened needle be used. If this should fail, and especially when the number of objects to be transferred to balsam is large, the alcohol may be supplanted gradually. Dr. Mayer has thus prepared very young larve of Echinoderms. ‘The specimens were taken up in a capillary tube, with the surrounding alcohol, and then placed in a tube, with a drop of oil of cloves at the bottom. After the lapse of half-a-day the larve, which at first swam on the top of the oil, had gone to the bottom of it, and could be easily removed again by the same tube. Objects may be left in oil of cloves for months without any apparent detriment. Sie ep 880 SUMMARY OF CURRENT RESEARCHES RELATING TO Recently Kleinenberg has recommended the use of colophonium instead of Canada balsam. The solution in absolute alcohol is not suitable, as under certain circumstances the finished preparations will show large bundles of. crystals. ‘Turpentine should be used as a solvent ; this, however, has the disadvantage that the preparations dry very slowly. The solution in chloroform seems to answer well, but must be filtered before use. Further experience is required with this medium before its use can be strongly recommended. A solution of sandarac in absolute alcohol, which at first appeared to answer well, has not, on further trial, proved satisfactory. V. Dissectinc.—F or the dissection of single organs, fresh animals are generally placed in dilute alcohol, or a weak chromic solution. But the tissues are liable to suffer from maceration in these fluids, and hence, where it is important that the tissues should be well preserved, it is advisable to use picro-sulphuric acid, regardless of the mjurious effects of the same on the dissecting instruments. The fluid should be changed as soon as it gets thick and the preparation well washed in alcohol afterwards. The hardening capacity of the picro-sulphuric acid is extremely slight, but may be strengthened by the addition of chromic acid. Preparations thus obtained, and subsequently treated with alcohol, staining fluids, &c., should be transferred to creosote for further dissection, as the transparency induced by this medium will greatly facilitate the work.* VI. Impeppine.— For section-cutting, objects are usually imbedded in paraffin. By low temperature, as in winter, it is necessary to work with a softer paraffin than is required for summer. Instead of softening by an admixture of lard, as generally done, it is better to use a paraffin which becomes soft in summer, on account of its con- taining liquid hydrocarbons, and is preferable to lard as it is not liable to become rancid. Preparatory to imbedding, the objects are removed from absolute alcoholt to creosote, clove oil, or chloroform, and left until they become thoroughly saturated. ‘The penetration of the clarifying fluid may, in some cases, be advantageously hastened by warming a little. They are next placed in soft paraffin, heated to about 50° C. over a water bath, and allowed to remain for an hour or so. The soft parafiin is then turned off and replaced by a mixture of hard and soft parafiin,t heated to about 50° C. After remaining for half-an-hour or less in the harder paraffin, kept at a steady temperature, they are ready for imbedding. For this purpose a small paper box may be used; or, much better, a box made of two pieces of type-metal, as used in Professor Leuckart’s laboratory. As will be seen from Fig. 162, each * In the original paper Dr. Mayer speaks not of creosote, but of oil of cloves. The brittleness which is caused by it is in most cases advantageous, but can easily be reduced by the addition of creosote. ‘The tendency to collect in small drops which is peculiar to oil of cloves may be counteracted by the addition of oil of bergamot. + In many cases a lower grade of alcohol will suffice. $} The ratio of combination must be determined by experiment, since it will depend on the quality of the paraffin and the temperature; two parts of hard to one of soft work very well for the winter temperature of Naples. ZOOLOGY AND BOTANY, MICROSCOPY, ETO, 881 piece of metal has the form of a carpenter’s square, with the end of the shorter arm triangularly enlarged outward. A convenient size will be found in pieces measuring 7 em. (long arm) by 3 cm. (short arm), and 7mm. high. With such pieces a box may be constructed at any moment by simply placing them together on a round plate of glass, which has previously been wet with glycerine and gently warmed. The area of the box will evidently vary according to the position given to the pieces, but the height can be varied only by using different sets of pieces. In such a box the paraffin may be kept in a liquid state by warming now and then over a spirit-lamp, and small objects be placed in any desired position under the Microscope. It is well to imbed in a thin layer of paraffin, so that the object, after cooling, may be cut out in small cubical blocks, which may be easily fixed, for cutting, Fia. 162. to a larger block of hard paraffin. Only in the case of very delicate objects is imbedding in wax and oil after Briicke’s plan to be preferred. White of egg has not proved as permanent as might be desired. Gelatine is a convenient imbedding medium, and Dr. Mayer has devised a process by which it is deprived of its elasticity. It is allowed to soak as usual in water, then heated and } to} a volume of castor oil added, shaken well, and shortly before getting cold pour the mixture into a bowl. When afterwards all the castor oil has been extracted by 90 per cent. alcohol the. gelatine remains as a fine porous matter, a sort of artificial pith, and is at once ready for use. It must not of course be exposed too long to the air as this would soften it. Under the Microscope this form of gelatine is less troublesome than lilac pith and has the advantage that it can be produced in any size and always even. VII. Currine.—Objects are cut dry with a microtome, and the rolling of the sections may be prevented by holding a thin narrow spatula over the edge of the knife while cutting. The spatula may be made of brass, or of paper fastened to a flattened needle. The spatula should be bent slightly, and the convex face held over the paraffin without pressure. A small brush, slightly flattened, is used for the same purpose in Leipzig. Andres’ Methods of treating Actinie.*— Among the various methods employed by Dr. Andres in killing the Actinie, the three following, given in the order of their excellence, are said to have worked most satisfactorily :— A. Corrosive sublimate——With small animals a hot solution, used in the manner recommended by Dr. Lang, gives good results; with * Atti R. Accad. Lincei, v. (1880) p. 9. 882 SUMMARY OF CURRENT RESEARCHES RELATING TO larger animals, where this mode of treatment fails, the fluid must be injected. The cannula of a glass syringe, filled with the hot fluid, is inserted into the mouth at the moment it opens, which act habitually follows on gently touching the lip. After injecting, the hot solution is poured into the glass containing the animal and a small quantity of sea water. If the operation is cleverly performed, the animal remains fully expanded, as the mechanical pressure of the injected fluid prevents contraction. After from five to fifteen minutes the animal is washed in distilled water, and allowed to remain twelve hours in 50 per cent. alcohol,* then passed through the higher grades of alcohol. Borax-carmine and hematoxylin used for staining. . B. Glycerine and Alcohol.{~— Glycerine .. a .. 20 parts. Alcohol (70 per cent. mh AO Sea water .. a3 »» “A This mixture, poured very Aus into the containing glass, often gives very good results, both for anatomical and histological pur- poses. C. Nicotine and Tobacco Smoke.—a. A solution of nicotine (1 g.) in sea water (1 1.), conducted into the vessel containing the animal fully expanded in a half litre of sea water, by means of a thread suffi- ciently large to empty the flask holding the nicotine solution in the course of twelve hours. b. The vessel containing the animal in an extended condition, covered by a bell-jar in which tobacco smoke is confined, until the animal becomes completely benumbed. After being deprived of sensibility by either of these methods, the creature may be killed in corrosive sublimate, or in picro- sulphuric acid. D. Dr. Andres finds that in the use of chloroform, dropped slowly into the water, or administered in form of vapour, maceration usually sets in before the power of contracting is lost. Good preparations of the internal parts may be obtained by injecting a weak solution of osmic acid. The method of freezing has also been employed with some success. For this purpose three vessels are placed one within the other, the central one containing the Actinia, the middle one ice and salt, and the outer one cotton. The ice containing the congealed animal is dissolved in alcohol or an acid. E. Maceration —It is often important to see the cells of a tissue in situ before freeing them with needles. In such cases Dr. Andres proceeds as follows :— 1. Killed with corrosive sublimate. 2. Left in 25 per cent. alcohol twenty-four hours. * A little camphor (1-100 ccm.) added to the alcohol will facilitate the removal of the sublimate. + This method originated with S. Lobianco. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 883 3. Soaked for a short time in a very thin solution of gum arabic then in a somewhat thicker solution, and finally imbedded in a very thick solution. 4, Hardened in 90 per cent. alcohol. 5. Thick sections prepared for dissection with needles. The sections are placed on a slide in water, which dissolves the gum. Flemming’s further Method for Staining Nuclei.* — In his recent researches on karyokinesis, W. Flemming states that he obtained serviceable staining of nuclei in the following ways :— 1. Living eggs of Echinoderms coloured on the slide, either with safranin or aniline dyes, followed by acetic acid (1 per cent.) which is allowed to flow under the cover and thus replace the staining medium, or with acetic acid carmine (after Schneider), used undiluted. The last mentioned staining agent causes swelling, but still gives the typical features of the karyokinetic figures. 2. Eggs first hardened in strong nitric acid (40-50 to aq. dest. 60-50), then washed in distilled water until the yellowish colour, due to the presence of the acid, disappears. Coloured with acetic acid carmine. Iodine-green and Methyl-green t—Dr. M. Flesch calls further attention to the suitability of the combination of the green with red staining matters. He has excellent preparations of cartilage, skin, and glands hardened in Miller’s fluid and alcohol, and stained with methyl-green, and afterwards with picrocarmine. If the colour is not so beautiful as in the case of objects stained with carmine and hematoxylin, it is nevertheless very useful, as it is, he believes, easy to preserve, and moreover it gives very sharp ditferentiations. Dr. Flesch uses an aqueous solution of commercial methyl-green diluted: until the section in a watch-glass is still recognizable on a bright ground. Preparation of Epidermis.{—W. Pfitzner prepares the epidermis of tadpoles by first hardening in chromic acid, and making fine sections with the Thoma microtome of a piece as free as possible from pigment, imbedded in elder pith; the best thickness for the sections is ‘01 to ‘015 mm. The sections are washed for at least thirty minutes in distilled water to remove the chromic acid. Pfitzner has three methods of mounting, either of which may be employed, with various modifications :— 1. Staining. a. With saffranin, mount in dammar. 0b. With hematoxylin, mount in dammar; or, c. As b, but mount in glycerine. 2. Gold treatment :—Treatment with 1 per cent. solution of gold chloride, with a trace of hydrochloric acid, for 15 to 30 minutes, in the dark; the sections are then carefully washed and exposed to . daylight for 12 to 24 hours in a 5 per cent. solution of formic acid, * Arch. f. Mikr. Anat., xx. (1881) p. 1. Cf. Amer. Natural., xvi. (1882) p- 780. See also Flemming’s earlier method, ante, p. 715. ’ + Zool. Anzeig., v. (1882) pp. 554-5. t Morpholog. Jahrb., vii. (1882) pp. 731-2. See also ante, :p. 871. 884 SUMMARY OF CURRENT RESEARCHES RELATING TO and then carefully washed again and mounted (a) simply in glycerine, or (b) in dammar, after staining with saffranin. The delicacy of the sections necessitates the employment of good daylight, and illumination from below in their manipulation; the latter end may be attained by employing as working stage a cigar box, from which the front side has been removed, putting a piece of glass on the top, and an oblique mirror inside. Great care must be taken not to allow contact between the sections when made, as they would then probably become entangled. Unpressed Mounting.*—Under this heading Mr. A. W. Stokes describes the mounting of the tongue of a blow-fly “ without pres- sure,” so that its true shape is preserved, a halfpenny test-tube being all the preparing apparatus required. Into this test-tube place the fly’s head, and fill the tube half-full with a solution of soda and potash. Stand the tube in boiling water, and leave it on the hob of a fire to keep hot till morning. Then examine the head and see if it looks almost transparent; if not, pour oft the soda solution and add a fresh supply, and again keep the tube hot till the object becomes semi-transparent. Now pour off the solution and add hot water, in a few minutes emptying it out and adding some more:—Repeat this at least three times, and finally leave the last quantity of water on the object for an hour to cool. Next pour off all the water and replace it with spirit of wine; methylated spirit, if strong, will do sufficiently well. Heat this by immersing the tube in a vessel of hot water for one minute; then take it out, cork it up, and leave it for one hour. So far we have, by means of the soda-solution, destroyed all the flesh and fat tissues, leaving only the cuticle and internal organs, such as the trachez, &c. In doing this, we have filled up most of the few natural air-spaces with soda-solution, which, however, being a some- what dense fluid, would not enter many of the narrow tracheal tubes. Then with water we replaced the soda-solution, and washed away the parts destroyed thereby. On replacing the water by alcohol, a still less dense fluid, more of the finer air-spaces are penetrated and the air driven out; there are still, however, some tubes too minute even for alcohol rapidly to enter. So now we pour off the spirit, and add ether instead, which answers a double purpose; it enters the very minutest passages, displacing the contained air, and it also dissolves the globules of fat left unsaponified by the soda-solution. After leaving the ether for fifteen minutes in the corked tube, and shaking it once or twice, we pour it off and add turpentine; and then in ten minutes time the head is ready for mounting in Canada balsam or dammar. If so mounted, however, it will be very difficult to see much of the finer internal structure, since these media render some parts far too transparent; and hence some of the glycerine media are pre- ferable. In such cases, after pouring off the ether, add alcohol, and at the end of fifteen minutes replace the alcohol with cold water, and * Journ. Post. Mier. Soc., i, (1882) pp. 129-35. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 885° leave for fifteen minutes more. Then the water may be poured off, and the mounting-fluid, whether glycerine, carbolic-acid, gelatine, Goadby’s or Thwaites’ fluid, may be added. The object, if mounted in any of these, will have a far more natural appearance, and show more plainly the finer structures, than if mounted in Canada balsam. The times mentioned above are those it is necessary in most cases to wait, but longer intervals would often be preferable. If we are busy the tube and its contents may be left at any stage of the proceedings for days, with a certainty that the object will only benefit by the delay, except in the case of the soda-solution. It is not necessary to use distilled water, though it is better to do so; but whatever water is used, it should be just freshly boiled and be used hot. Cold unboiled water contains a large quantity of air, and if used in that state will certainly impart air to the object instead of helping to extract it. The soda or potash solution is made by adding solid potash or soda to eight times its weight of boiling water, and the only expense of the process is for the tube, soda, alcohol, and ether—a pint of each of the latter will prepare some thousands of specimens. The same system will answer for sections of wood, small seed- vessels, leaves, &c., only they must first be decoloured by pouring sodic hypochlorite into the tube, then, after well washing with water, the rest of the process may be followed as before, leaving out entirely the use of the soda-solution. The great difference is in the matter of speed, vegetable preparations being made far more rapidly. It is possible to cut a dozen sections from a living branch, bleach, stain, and mount them in Canada balsam or glycerine-solution, and finally, ring and label them, all within the hour. Should any of the preparations—the blow-fly’s head, for instance —become too colourless and transparent, all we have to do is to stain them by the addition of a few drops of an alcoholic solution of some colouring matter (logwood answers well) to the alcohol in the tube. The subsequent use of ether will fix the colour. Usually, after this treatment, the object will be found to be quite clean; but if not, it should be gently brushed with a camel-hair pencil while in the turpentine or glycerine fluid. The wings of many insects are partially destroyed during the process, but since these can, if desired, be easily mounted separately, this is not of very great importance. Directions are also given for mounting the object as above prepared in cells, the use of vulcanite rings being recommended. Staining with Magdala-red.*—Dr. C. Norner refers to the fact that picrocarmine (Ranvier’s) affects different classes of animals very differently. Tape-worms, for example, redden very quickly, while other worms, like the Nematodes, take very gradually a yellowish tinge, because in their case the picric acid takes effect first and the carmine only after a longer time. Mites are also affected variously—some become yellow, others red, and others perhaps remain colourless. Magdala-red is not open to these objections, and * Arch. f. Mikr. Anat., xxi. (1882) pp. 354-5. 886 SUMMARY OF CURRENT RESEARCHES RELATING TO is an exceedingly useful staining medium, because it answers all re- quirements in an equally favourable way. It possesses a marked differentiating power, and even surpasses picrocarmine in this excel- lent quality. It colours all tissues uniformly, whether they are fresh or are taken out of alcohol or chromate of potash. What is most important is that the differentiating power is well manifested in botanical preparations, in which each tissue takes a special tint. Care however must be taken that the sections remain only a few minutes in the solution, because it stains with remarkable intensity. For the examination of sieve-tubes (preserved with so much difficulty) Magdala- red will doubtless be very suitable. The vessels of the plerom are very clearly distinguished from the periblem, &c. The lower fungi also, such as Mucor, Penicillium, Aspergillus, &c., also take a- beautiful colour, like histological sections. An exceedingly satisfactory result is likewise obtained with parasites (mites, worms, &c.). A further advantage is that this dye has a great capacity of resistance to potash, and thus, if required, specimens can be first stained and then treated with potash. For double staining it does not seem to be suitable, as it destroys the other colour. The author adds, “ whether it does not possess the same disadvan- tage as hematoxylin and other aniline colours, and disappears from the preparation after a time, and is therefore unstable, I am not yet able to determine.” Preparing Fossil Foraminifera, Spicules, &c.*—In a second papert Mr. C. Elcock gives directions for preparing fossil Fora- minifera. The material from which they may be most easily pre- pared is chalk powder, many ways of doing which are recommended by text-books, but all unsatisfactory in practice. The only material worth handling from which to obtain the Foraminifera found in the chalk in a condition almost, if not quite, uninjured, is the powdery matter found in the cavities of the flints which abound in the chalk, but especially in cavities in the large nodules known as “ Paramondras ”—masses of flint of very irregular - ovoid form in which are cavities of various sizes filled with chalk containing Foraminifera, which as a rule are in fine preservation. On no account should the plan be adopted of shaking up the powder with water in a bottle, which is worse than useless ; but if it is dry, the first thing is to sift it through a rather coarse sieve—zine perforated with holes 7 inch in diameter will do—so as to remove all the fine flakes of flint, which would cut gauze like lancets. If damp or wet, the powder may be washed through this zine sieve under the tap into asieve (9 inches in diameter and 4 inches deep), with Miller’s silk-gauze 180 threads to the inch. Hither way will answer well, but after much experimenting Mr. Elcock prefers first to dry perfectly and sift dry. What will not pass through this zine sieve must be well and carefully washed, and looked over when dry, as it will contain * Journ. Post. Micr. Soc., i. (1882) pp. 139-45. + First paper (on recent Foraminifera) loc. cit., pp. 25-9. Cf. this Journal, ante, p. 436. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 887 the largest forms, some of which, as Nodosaria, Dentalina, &c., may be nearly half-an-inch long. A large cup-full of the fine sifted powder must now be put into the silk-gauze sieve, and a good stream of clear fresh water be allowed to wash it until all signs of milkiness have disappeared, and the water runs away quite clear, neither fingers nor spoon being used to stir up the material, but letting the stream of water from an indiarubber tube fixed to the water supply do all the work, directing it so as to move the powder well about. When the water runs away clear, wash all into a corner of the sieve, drain, and tip out the chalk powder on to a plate to dry thoroughly in the oven. Repeat this process until all is washed ; and when dry and cold sift into sizes for examination. The finest siftings will probably be the richest in species. If the chalk- powder is good and the washing properly done, a considerable portion will be found to consist of Foraminifera, Ostracoda, sponge, and other spicules, the remainder being sand, &c. If sponge spicules or other siliceous organisms only are being sought for, pour dilute hydrochloric acid over the chalk-powder, and let it remain for a day or two to remove all the lime; after which pour off the acid, and wash well with clean water until every trace of the acid is removed ; then dry, sift, and examine. As these Foraminifera are fossil and mostly siliceous they will not “float,” but the washed material must after drying be examined under the Microscope and the individual shells picked out with a fine miniature red sable pencil, and for doing which there is no royal road. The best tray for the purpose is one made of black ferrotype plate 4 inches x 13 inch with the edges on each side and one of the ends neatly turned up about ; inch, on which a layer of the washed material is spread as thinly as possible, and the tray passed regularly from right to left across the field. Directions are also given for dealing with fresh dredgings of sea- mud, shore-mud ,&c., and with ship’s soundings, where the Foraminifera are mixed with tallow, lard, &c. Of all ways of mounting Foraminifera none is to be compared with mounting them as opaque; they look best without a cover-glass. Ebonite rings should be selected of such sizes that one will just fit inside the other, the smaller being cemented to the slide and the larger to the cover-glass. Preparation of Diatoms.*—Prof. J. Brun describes the following process which he employs for destroying the endochrome of diatoms. If the diatoms are fresh and wet, crystals of permanganate of potash should be added, and 10 parts water for each 1 part of the salt. If the diatoms are dry (pure or mixed) they should be wetted with a little of the concentrated solution of the salt, having even crystals in excess. The reaction of the permanganate should last about 12 hours. The mixture (placed in a 100 gr. phial) should be stirred occa- sionally and put in the sun or on a warm stove. The phial should ‘ * Journ. de Microgr., vi. (1882) pp. 457-8. 888 SUMMARY OF CURRENT RESEARCHES RELATING TO then be half filled with water and 0°50 cgr. of calcined magnesia added and left to act for 2 or 3 hours, shaking it now and then. Pure hydrochloric acid is then added in 1 gramme doses every 10 minutes, and when the contents of the phiai are colourless the operation is completed. To facilitate the reaction the phial may be plunged in warm or boiling water. The absolute purity of the distilled water to be used for the subsequent washings is an essential condition of success. In this process we have first the energetic oxidization of the endochrome by the permanganate, then, by means of the acid, there is a disengagement of oxygen (or combustion), and finally the disengagement of chlorine which bleaches. It is to these successive reactions inside and outside the valves, to which must be attributed the perfect cleansing of their silex. By this treatment the- delicate species are not corroded, particularly if, before the action of the acid, enough water is added. The surfaces of the valves will be found to have lost all their coleacterine, and the minuter details, striae or dots, clearly shown. The author has tried all the different physical and chemical processes which have hitherto been announced, and he has found none which succeed so completely and so regularly. Mr. Kitton writes * that whilst theoretically the method appears to be a good one he fears that it will not prove so effective, when much vegetable or animal matter is present, as the old sulphuric acid and chloride of potash process. Mounting Sections in Series.—The use of shellac} for fixing sections on the slide, introduced by Dr. W. Giesbrecht, is a very valuable addition to histological methods, as hundreds of small sections may be arranged in serial order, and all inclosed in balsam under the same cover without danger of disarrangement. The method is further extremely useful in mounting larger sections, particularly those composed of loose parts, or parts liable to swim apart. The shellac is prepared and used in the following manner :—One part of bleached shellac} is mixed with ten parts absolute alcohol, and filtered. The slide is first warmed to about 50° C., and then a thin film of the shellac laid on by a glass rod drawn once over its surface. Before using, the slide is again warmed, and the shellac surface washed with oil of cloves for the purpose of softening it.§ * Sci.-Gossip, 1882, p. 257. + MT. Zoolog. Station Neapel, 1881, p. 184. Cf. C. O. Whitman in Amer. Natural., xvi. (1882) pp. 783-4. Also this Journal, i. (1881) pp. 953-4. t Dr. Mark uses the bleached shellac in the form in which it is prepared for artists as a “ fixative” for charcoal pictures. It is perfectly transparent, and a film of it cannot be detected unless the surface is scratched. He attaches a small label to the corner of the slide, which serves for the number of the slide and the order of the sections, and at the same time marks the shellac side (otherwise not distinguishable). § Cf. this Journal, i. (1881) p. 953, where the following direction is given :— “ Before commencing cutting, brush over the shellac layer very thinly with creosote, and then lay the section upon it with as little paraffin as possible.” ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 889 The wash is made with a small brush drawn backwards and forwards until the entire surface has been moderately but evenly wetted with the oil. Sections are now cut and arranged for the first cover; this done, the slide is warmed over a spirit-lamp so that the paraffin adhering to the sections melts and flows together, forming an even layer, which cools almost instantly, and thus secures the position of the sections while those of the second cover are prepared. The sections for the last cover having been completed, the slide is warmed for ten minutes on a water bath, in order that the sections may sink into the shellac and become fixed, and the oil of cloves evaporate. After allowing the slide to cool the process is concluded by washing away the paraffin with turpentine, and mounting in balsam dissolved in chloroform. The following mode of fixing sections is described by Dr. J. Gaule* :— The sections are cut dry and placed on the slide in the order and position in which they are to be mounted. They are then smoothed out by the aid of a fine brush wetted in 50-60 per cent. alcohol, until all wrinkles are removed and every part is in close contact with the slide. The slide is allowed to stand several hours (or over night) until the alcohol has completely evaporated, and the sections are left adhering quite firmly to the glass. The process may be hastened by gently warming to 45-50° C. The paraffin may be removed by any of the solvents in common use, but xylol is recommended. A few drops are allowed to flow over the sections, and after a few moments the paraffin is fully dissolved. The balsam (a mixture of balsam and xylol in equal parts) is placed on the cover-glass, and this allowed to sink slowly, from one side, over the sections. Dr. Gaule finds it convenient, especially with serial sections, to use large cover glasses—often nearly as large as the slide itself. Thus a single slide may often contain a large number of sections closely arranged under one cover. For large sections this method offers one important advantage over that of Dr. Giesbrecht; by the former all wrinkles may be removed, while by the latter the sections must lie as they fall. In the case of smaller sections, not liable to get wrinkled during the placing, Mr. Whitman f¢ prefers the shellac method. Eau de Javelle for Removing the Soft Parts of Preparations.{ —Dr. F. C. Noll has found eau de javelle (subchleride of potassium KC20) very suitable for preparations of Spongilla, and for destroying the protoplasm in other objects. If siliceous sponges are burnt or boiled in potash the hard parts, spicules, &c., separate, and are not shown in their proper * Arch. f. Anat, u. Phys, 1881, Phys. Abthlg., p. 156. Cf. also this Journal, ante, p. 428. ¢ Loc. cit. t Zool. Anzeig., v. (1882) pp. 528-30. 890 SUMMARY OF CURRENT RESEARCHES RELATING TO connection. To remedy this a piece of the sponge is placed on a slide covered with some drops of eau de javelle and left to stand with a glass over it, until all the soft parts are dissolved, which, in the case of thin sections, does not take more than 20-30 minutes. Gemmules take a longer time and should be left over night; their contents are dissolved without destroying the outer coat. When the protoplasm is all dissolved the object is carefully treated with acetic acid which removes all precipitated matters, then with weak and afterwards with absolute alcohol. Finally oil of cloves (which in 15 minutes completely clears any cloudy gemmules) prepares the way for mounting in Canada balsam. The gemmules of Spongilla fluviatilis, S. Lieberkiihnii, and S. contecta, from specimens which spread out on the under side of stones, remain in situ between the spicules, and give a perfect representation of the form of the sponge. In the more compact sponges, such as the free growing specimens of §. Lieberkiihnii, the spicules remain united to the framework, although the lining and cementing substance has been dissolved. The layer by which the sponge is attached to its support, like the membrane of the gemmules, is not destroyed ; it is not, how- ever, turned black, like the latter, with a solution of nitrate of silver. These three elements of Spongilla have, therefore, a different chemical composition. Diatoms are often found in the tissues of sponges, and these are as well prepared by the above process as they are after burning or boiling with sulphuric acid, so that eau de javelle is to be recom- mended as a very useful reagent for diatoms also. To ascertain the effect on calcareous forms small mussel or snail shells (with or without epidermis) were laid in eau de javelle. They were clean and partly colourless but their lime remained uninjured. The same was the case with the calcareous bodies from the crust of different Gorgonide. Small skeletons can be cleaned of skin, muscle, &¢., without injuring the bones. The liquid is also admirably adapted for cleaning vegetable sections. Potash and glycerine swell up the cell-walls or break up the preparations. In a quarter of an hour the sections are freed from all the soft parts and show only the clear cell-walls. After treatment with acet'c acid they are mounted in Mayer’s fluid (glycerine 1 vol., distilled water 2 vols., and to 10 vols. of this mixture 1 part salicyl- pyrogallic acid) or in gelatine-glycerine, balsam rendering the cell- walls too transparent. Gum and Glycerine for Imbedding.*—L. Joliet has found that the soap which he was in the habit of using for imbedding, and which succeeded perfectly with the Salpew, gave very bad results with Pyrosoma. It did not penetrate the common transparent substance which envelopes all the ascidio-zoids, so that they were rapidly distorted, and could not be cut. The following combination has, however, been of the greatest use :— * Arch. de Zool. Exper. et Gén., x. (1882) pp. xliii—y. ZOOLOGY AND BOTANY, MICROSOOPY, ETC. 891 Dissolve in a little water some very pure gum arabic, so as to obtain a liquid having the consistency of a thick syrup.* Pour a little into a watch-glass, so as not to quite fill it, Then add from six to ten drops of pure glycerine, and with a small stirrer carefully mix the gum with the glycerine until it forms a homogeneous mass. Then lay the preparations on the surface of the liquid, and with needles press them into it. This done leave the whole to dry, which takes from one to four days, according to the condition of the air. The gum will assume the consistency of cartilage; without being soft it is supple and yields to the finger. The cake of gum is then cut into squares or strips, corresponding with the preparations, and removed. A plate of gum enclosing the preparations is thus detached without difficulty from the bottom of the watch-glass. These plates are turned over and again allowed to dry until they are wanted for use; they may be preserved in good condition almost indefinitely, the gum, when mixed with a sufficient quantity of glycerine, never becoming hard or brittle. The following are points to be noted :—Between the limits of 6 to 10 drops of glycerine above mentioned, the proportions most suitable to the nature of the object under examination and to the season of the year may be found by experimental trials. Too much glycerine prevents the gum from acquiring sufficient toughness, too little allows it to become brittle. In the winter or in rainy weather less glycerine should be added than in the summer or in dry weather. It is often well to soak the object in glycerine before putting it into the gum; the quantity of glycerine thus absorbed by the object being taken into consideration, and less added directly to the gum. ~ With a stove or by the help of the sun the gum can be very quickly dried, but in most cases it is a question of patience. It is one of the great advantages of the gum and glycerine that they dry so gradually; they are generally liquid the first day, pasty the second, and cartilaginous the third. The object having remained in this liquid for twenty-four hours is perfectly soaked, the gum having penetrated into all the interstices of the cells, and the sections pre- serve the relations of organs which are not directly connected. With soap or gelatine the imbibition is in many cases less perfect, because, unless a high temperature is maintained for a long time, the solidifi- cation of the mass takes place too quickly and does not allow the liquid to penetrate so deeply into the tissues. When the strips are removed from the watch-glass, it is better to wait until they have assumed such a consistency that they cannot be easily bent. It is after having waited almost a week that the author has always obtained the best sections. Gum alone rapidly becomes hard and brittle; the effect of the glycerine is to preserve it almost indefinitely in a cartilaginous consistency. Another advantage of the method is the perfect trans- parency of the substance surrounding the object to be cut, so that it * Solutions of gum, sold under the name of strong white liquid glue, may also be used. They have the advantage of having a uniform consistency. 892 SUMMARY OF CURRENT RESEARCHES RELATING TO is easy to examine the preparation under the Microscope before cutting ; the smallest details can be distinguished, and with a low power the object can be arranged very accurately, and the section can be made exactly through the desired point. The sections being thus made, they are placed on a glass or a very dry surface, then taken up with a needle or fine moist brush and placed on the slide in a drop of water; the gum dissolves and leaves the preparation in place. A drop of glycerine placed at a corner of the cover-glass, quickly penetrates under it and replaces the water (which evaporates), and mixing with the melted gum, forms an excellent preserving liquid. Roy’s Microtome.*—Dr. C. S. Roy describes a microtome (Fig. 163) for cutting frozen or otherwise hardened substances. The knife h is connected with the metal bar c by the clamp g. A small piece of leather laid on the back of the knife at the place where it is held by g enables the section to be made at any desired angle to Fic, 163. ‘ith nN the horizontal. By a handle n the bar c can be moved on the pivot e furnished with the milled head fi The pivot passes through the support b which is attached to the base plate a. The knife is thus able to move over the object plate d, describing a circle on the pivot e. The object plate may be raised or lowered by k, and its under surface is deeply fluted, with the object of diminishing the thickness of the * Arch. f. Mikr. Anat., xix. (1881) pp. 137-43 (1 pl.). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 893 metal, and increasing the surface exposed to the ether-spray, which is applied by an arrangement of tubes supported bya rod 1. The plate is large enough for pieces of tissue from 4 to 5 mm. by 24 mm. downwards. Fic. 164. General directions are added as to freezing and cutting which it is un- necessary to repeat here. Specimens otherwise hardened, however, Dr. Roy prefers to imbed in a mixture of wax and olive-oil shaped in a mould to fit in the frame (Fig. 164), which is made by removing the plate d and adding a third vertical plate c, which is fixed by the screws b. A spring presses the plate e forward so as to prevent any lateral movement of the imbedding mass. The microtome is fixed to the table by a clamp with a screw the head of which is seen at m. Dr. Roy adds subsequently * that the essential points for which he claims novelty in this microtome are the peculiar structure of the object-plate to increase the surface exposed to the ether spray, and the improvement in the manner of attaching the knife. Professor C. Weigert,f in preference to the English razor, employs the knives made by Hartel of Breslau or Frank of Leipzig, for making the sections, as having a perfectly level surface and not rubbing with the lower surface the object which iscut. By applying the sliding principle of the Rivet microtome he avoids the pressing action of the razor which, for soft specimens, is 0 undesirable—a drawing motion being thus substituted. He diminishes the area of the plate over which the razor travels by bending its sides somewhat down. When using the sliding principle the objects must not be frozen too hard. When sections have been made by the freezing plan they are examined fresh or in salt solution. Boecker’s Microtome with Automatic Knife-Carrier.t—Although the microtome has now reached a high degree of perfection (writes E. Boecker) many defects still exist in the usual forms, as well as in those with sliding carriers for the knife. For this reason, perhaps, many still prefer free-hand cutting with the razor, although it is scarcely necessary to remark how little accuracy can be thereby obtained, and what inferior sections of often valuable material are turned out. The principal fault of the microtomes hitherto con- structed, consists in the frequent tearing of cells or tissues, caused— at least in slide microtomes—by the fact that the knife is often wrongly placed and having only a forward movement, presses the object rather than cuts it. It is at least expected of a good micro- tome that with careful manipulation not a single section should be lost, a requirement of the utmost importance in series sections, or in * Arch. f. Mikr, Anat., xix. (1881) pp. 527-8. + Arch. Path. Anat. u. Physiol. (Virchow), Ixxxiv. (1881) pp. 287-90. } Zeitschr. f. Instrumentenk., ii. (1882) pp. 209-12 (4 figs.). Ser. 2.—Vot. II. So 894 SUMMARY OF CURRENT RESEARCHES RELATING TO rare pathological injections, so that it should be possible to make extraordinarily thin sections without the least tearing of the cells or tissues. How far the thinness of the sections can be carried is, of course, different in different objects, and it is therefore difficult to lay down any hard and fast rules. For the fulfilment of these requirements Boecker first endeavoured Fig. 165, S LL SSSSSSSSSSSS SSS SSS SES ———$_————_—__$_SSSSSSSS to give to the knife the proper movement, so that it should move in the same way as if guided by the hand. It appeared to him that the ordinary method of moving the knife by means of a slide was not sufficiently firm, and involved the inconvenience of keeping the slide steady by the hand. He also decided to give the knife such a con- siderable inclination that it should be nearly parallel with the direc- tion of the slide. This attempt was successful in every respect. Two slides of brass-plate are connected in such a manner that their movements shall cross at right angles. If the one slide §’ (Fig. 165) is moved ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 895 longitudinally it must at the same time push the other slide § to the side. For this purpose 8’ is provided with an oblique slit, in which the tube h slides backwards and forwards. The latter is attached to the plate a. The cylinder r serves for the reception of the object to be cut, and by means of the micrometer screw can be raised by hundredth parts of a millimetre, for which purpose a scale b with index d is added. The slide § has also a transverse slit, so that it does not come in contact with the tube h, and can move freely to a certain distance. The attachment for the knife is on the slide 8’ ; the stability of the knife m is ensured by securing it in two places, first to the angle-piece k, which can be clamped in any position, and with the slide 8’; and secondly by means of the screw m' which, with the piece belonging to it, moves in a slit as shown in the figure. The slide 8’ is moved by the handle g, and the oblique slit enclosing the tube h (see Fig. 166) causes the slide S to move in the Fig. 166. Fic. 167. = direction a a’, and thus effects a “ drawing” movement of the knife. This movement is uniform if the slit is straight, as in the figure, and it can be effected quicker or slower according as the slit is more or less oblique. The drawing movement can also be accelerated during the cutting process ; but in this case the slit must have a curved form, as in Fig. 167. The whole microtome must, however, be broader, although at the same time it may be shorter, By this arrangement the knife is able to cut in any oblique position. In the microtome described the cylinder has a diameter of 25 mm., amply sufficient in most cases, but capable of being increased. For cases where it is preferred to use the knife with the hand, a circular glass plate is added to the slide S’. Staining Bacillus tuberculosis.*—We have already described Dr. Koch’s original process for detecting this Bacillus and Dr. Ehrlich’s improvement upon it, as well as that of Dr. Van Ermengem.t Dr. H. Gibbes, referring to the unsatisfactory nature of the first two pro- cesses, says that the following simple process will bring out the bacillus with ease and certainty. It takes but a short time to carry * ‘Lancet,’ ii (1882) pp. 183-4. Brit. Med, Journ., No. 1137 (1882) pp. 735-6. + See this Journal, ante, pp. 385, 572, and 706. a oe 896 SUMMARY OF CURRENT RESEARCHES RELATING TO out, and the bacillus is stained so deeply and differentiated so fully from the surrounding substance that it can be seen with the greatest ease with an ordinary }-inch object-glass and daylight, the previous processes having stained it so faintly that high power or artificial illumination were required. The colours used are magenta crystals, which stain the bacillus, and chrysoidin, which stains only the sur- rounding substance. It is a brown which does not stain so intensely as vesuvin. The formule are :— Magenta crystals .. .. . . . 2 grammes. Pure aniline:".2.- ee. eee ees ms Alcohol (sp. gr. “830))~ -. <2 a.) ee = neers Distilled water... oes ws pene, ee eee Dissolve the aniline in the spirit, rub up the magenta in a glass mortar, adding the spirit gradually until it is all dissolved, then add the water slowly, while stirring, and keep in a stoppered bottle. Make a saturated solution of chrysoidin in distilled water and add a crystal of thymol, dissolved in a little absolute alcohol, to make it keep; a dilute solution of nitric acid (coml.) is also required, one part of acid to two of distilled water. The object of the process is to stain the sputum, or section, as the case may be, with a colour which the dilute nitric acid will remove from everything but the tubercle bacillus, and the subsequent staining with chrysoidin is only required to throw up the stained bacillus and make it more prominent. In Dr. Ehrlich’s process, the stain for the bacillus is too faint, and the vesuvin, used to stain the ground sub- stance, too opaque; consequently the bacillus appears a faint pink colour on a dense yellowish brown ground, and is not easily made out without high power or special illumination. His method of dissolving aniline in water, in which it is very sparingly soluble, is also open to objection, as it is very apt to vary in the amount taken up by the water. : For sputum the following process is the most simple. Spread a thin layer on a cover-glass and let it dry ; when quite dry pass it two or three times through the flame of a small Bunsen burner and let it cool. Filter two or three drops of magenta solution in a watch-glass, place the cover-glass with the sputum downwards on the stain, taking care there are no air bubbles under it. Let it remain for fifteen or twenty minutes, then wash in the dilute acid until all colour has dis- appeared, remove the acid with distilled water, when a faint colour will return; then place the cover-glass in the same manner as before on a few drops of chrysoidin filtered into the bottom of a watch-glass, and let it remain a few minutes until it has taken on the brown stain ; wash off the superfluous colour in distilled water and place the cover- glass in absolute alcohol for a few minutes, remove and dry perfectly in the air, place a drop of Canada balsam solution on the cover-glass and mount. It is better to use small glass funnels for filtering the stains, as they protect the fingers. Sections of hardened tissue are treated in the same manner with the necessary modifications. With regard to the powers required to examine the bacilli after ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 897 they have been mounted by this process, an ordinary }-inch with day- light will show them perfectly, and a } dry glass will show that they are rows of spherical bodies with the same illumination. Broun, J.—Préparation des Diatomées. (Preparation of Diatoms.) [Supra, p. 887.] Journ, de Microgr., VI. (1882) pp. 457-8. Pa » Note sur les meilleurs procédés pour reconnaitre les bactéries de la tuberculose et en faire des préparations microscopiques. (Note on the best pro- cesses for showing the bacteria of tuberculosis and making microscopical preparations.) [Post.] Bull, Soc, Belg. Micr., VII. (1882) pp. elxix.—Ixxvii. Journ, de Microgr., VI. (1882) pp. 500-3. Bryan, G. H.—Pollen as a Polariscope Object. [Pollen of Godetia polarizes “ quite distinctly though not in a very marked manner ”—also some others. | Sci.-Gossip, 1882, p. 231. Coir, A. C.—Studies in Microscopical Science. No. 22 (pp. 161-4).—Pilularia globulifera. The Pillwort. Transverse section of stem, stained logwood. Plate x 149. No. 23 (pp. 165-72).—The Lung. Vertical section Lung of Cat, injected carmine. Plate x 145. No. 24 (pp. 173-6).—Pilularia globulifera. The Pillwort. Transverse section of sporocarp, unstained. Plate x 62°5. No. 25 (pp. 177-84.)—The Thyroid Body. Transverse section of Human Thyroid Gland, stained carmine and sulph-indigotate of soda. Plate x 150. No. 26 (pp. 185-96).—On the minute structure of the Sporocarp in Pilularia globulifera. The Pillwort. Dolerite of Dalmahoy Hill, Edin- burghshire. Plate x 45, 65, and 150. No. 27 (pp. 197-200).—The Thymus Gland. H.S. Thymus Gland of Calf, stained logwood. Plate x 65. No. 28 (pp. 201-4).—Transverse section Thallus of Lichen. Sticta pulmonacea, Plate x 400. No. 29 (pp. 205-8)—The Pancreas. Transverse section of Human Pancreas (part of a lobule), stained carmine. Plate x 333. Davis, G. E.—The Dust from Boiler Flues under the Microscope. [Describes principally the minute spheres found on the bottom and sides of the flues. ] North. Microscopist, II. (1882) pp. 316-7, Ecertine, G.—Ueber die Anfertigung Mikroskopischer Priparate in der Phar- macie. (On making Microscopical Preparations in Pharmacy.) Deutsch-Amerikan. Apotheker-Ztg., New York, 1882, Nos. 13 and 14. Fiescu, M.—Kleine Mittheilungen zur Histologischen Technik. [1. Employment of Iodine-green and Methyl-green, supra, p. 883. 2. Monobromide of Naphthaline as a Mounting Fluid, post. ] Zool. Anzeig., V. (1882) pp. 554-6, FREDERICQ, L.—Note sur les préparations anatomiques seches & l’essence de térébenthine. (Note on dry anatomical preparations with oil of turpentine.) [Claim of priority (by 6 years) in publication of the method over Dr. Riehm and Professor Semper. Cf. I. (1881) p. 706, and ante, pp. 705-6. ] Zool. Anzeig., V. (1882) p. 588. Getei1z, A.—A search for “ Atlantis” with the Microscope. [Post.] Nature, XX VII. (1882) pp. 25-6. Grppes, H.—An Easy Method of Detecting Bacillus tuberculosis for Diagnostic Purposes. Lancet, II. (1882) pp. 183-4. 3» x, A New Method for the Detection of the Tubercle Bacillus. Brit. Med. Journ., No. 1137 (1882) pp. 735-6. Further Remarks on Staining Bacillus tuberculosis, (Supra, p. 895.] No. 1138 (1882) pp. 786-7. ” ? 898 SUMMARY OF CURRENT RESEARCHES RELATING TO Harrison, J.—Report of Lecture on Mounting Microscopical Objects. [Various receipts and directions. ] 1st Journ. and Rep. Braintree and Bocking Micr. and Nat. Hist. Club, 1882, pp. 9-10. Heron, G. A.—Ehrlich’s Method for the Detection of Tubercle Bacillus in Sputum. Brit. Med. Journ., No. 1137 (4882) p. 735. Hrrencocr, R.—Mounting Histological Specimens. [Remarks on T. C. White’s paper, ande, p. 438, and on mounting in fluids of various refractive indices. ] Amer. Mon. Micr. Journ., ITE. (1882) pp. 198-9. Kirton, F.—Tale. [Rarely used now for permanent preparations—sometimes substituted for selenite in polariscopes but not satisfactorily.] Sci.-Gossip, 1882, p. 232. » 9). Preparation of Diatoms. [Translation of and Note on Professor L. J. Brun’s paper. Supra, p- 887.] Sci.-Gossip, 1882, p. 257. Lewis, B.—On the Methods of Preparing, Demonstrating, and Examining Cerebral Structure in Health and Disease. Brain, Jan. 1881, p. 502, April 1881, p. 82, Oct. 1881, p. 351, Jan. 1882, p. 441, and April, p. 74. Lipsey, W., jun—A New Form of Constant Pressure Injection Apparatus. [ Post.] Amer, Mon. Micr, Journ., Il. (1882) pp. 187-9 4 fig.). M., C. J.—The Preparation of Dammar Varnish for Microscopic Purposes. [Post. Containing also direetions for a substitute for Canada balsam made by gently evaporating copal varnish and adding pure benzole.] Sci.-Gossip, 1882, p. 257. Map.esrone, C. M.— Observations on Living Polyzoa. [Contains note as to finding living specimens washed up on the beach. Post.] Trans. and Proc. Roy. Soc. Victoria, X VIII. (1882) pp. 48-51 (1 pl.). Martin’s (the late Joun, of Maidstone) Unmounted Objects. [Notice that the unmounted material from his laboratory has been forwarded to Rochester, N.Y., for sale.] Amer. Natural., XVI. (1882) p. 931. Maver, S.—Beitrag zur histologischen Technik. (Contribution to Histo- logical Technic.) SB. Wien. Akad., LXXXYV. (1882) pp. 69-82 (2 pls.). Meyer, H. v.—Modificirte-Form der Kleisterinjection. (Modified form of Paste Injection.) Arch. f. Anat. u. Physiol. (Anat. Abth.) 1882, pp. 60-1. Minor, —.—Ueber die combinirte Palladiumchlorid-Carminfarbung zur pathologischen Untersuchung der Centralnervensystems. (On Chloride of Pal- ladium and Carmine for Pathological Researches on the Central Nervous System.) Centrabl, f. d. Med. Wiss., 1882, p. 38. Mounting Classes, Microscopical. [Notice of the opening meeting of the present session of the Manchester Microscopical Society. ] North. Microscopist, II. (1882) p. 322. Moyret, M.—Micrographic Study of Dyed Silks. Chem. Review, XI. (1882) p. 203, from Teinturier Pratique. NeEELSEN & P. ScuIEFFERDECKER. Beitrag zur Verwendung der atherischen Oele in der histologischen Technik. (Contribution to the use of Ethereal Oil in Histological Technie.) Arch. f. Anat. u. Entwicklgsg., 1882, pp. 204-6. Nout, F. C.—Eau de Javelle als Mittel zum Entfernen der Weichtheile aus Microscopischen Praparaten. (Eau de Javelle as a means of removing the soft parts of Microscopical Preparations.) [Supra, p. 889.] Zool. Anzeig., V. (1882) pp. 528-30. Outvier, L.—lLes Procédés Opératoires en Histologie végétale. (Practical Processes in Vegetable Histology.) (Concld.) [Post.] Rev. Sci. Nat., II. (1882) pp. 71-91. RanpDALL, B. A.—An Economical Cabinet for Microscopical Slides. [Post.] The Microscope, II. (1882) pp. 134-5, from Western Medical Reporter. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 899 Renarp, A.—Description lithologique des Récifs de St. Paul. (Lithological description of the Rocks of St. Paul. [See supra, Geikie, A.] Sep. Repr. Ann. Soc, Belge Micr., 1882, 53 pp. Ricuter, P.—Préparations Microscopiques d’Aphidiens. (Microscopical Pre- parations of Aphides.) [List of 34 genera with number of species. ] Journ. de Microgr., VI. (1882) pp. 472-3. Serer, C.—Remarks on Grinding Knives for Cutting Thin Sections. [At the Montreal meeting of the Amer. Assoc. Ady. Sci. he stated that after considerable experience in grinding knives for cutting thin sections, he had found that the bevel of the edge should be the same on the two sides, and he explained a device which enabled him to ensure the true bevel without difficulty. ] Amer. Mon. Micr. Journ., III. (1882) p. 200. Smums, J.—A Collier’s Experience of Section-cutting. (Jocular story of an attempt to soften coal in carbonate of potash. ] Sci.-Gossip, 1882, p. 227. SzyszyLowticz, I.—Korallina jako odezynnik mikrochemiczny w _ histyjologii ros'linnéj. (Corallin as a micro-chemical reagent in vegetable histology.) Post. - ; Osobne odbicie z Rozpran Akad. Umiej.w Krakowie, X. (1882) 18 pp. Cf. Abstract in Bot. Centralbl., XII. (1882) pp. 138-9. Wuitman, C. O.—Methods of Microscopical Research in the Zoological Station in Naples—concluded. [Translation of P. Mayer’s article, ante, III. (1880) p.551. Supra, p. 866.] Amer, Natural., XVI. (1882) pp. 772-85 (5 figs.). Woop, J. T.—Manipulation. [Taking up cover-glasses by suction through a glass tube ending ina small piece of rubber tubing. Also small and light objects by a glass tube drawn out to a very fine point with the smallest conceivable hole through it.] North. Microscopist, II. (1882) p. 321. OBITUARY. The following Obituary notices were read by the President in his Address, ante, p. 145 :— Cuas. JosepH Hypr Auten, F.LS., F.G.S., F.Z.8., was elected in 1859 and appointed Treasurer of the Society at the Annual Meeting in 1862, but failing health compelled him shortly afterwards to leave England. Mr. Allen died 20th March, 1881, aged 62. Sir Antonio Brapy, Kr., J.P., F.G.S., F.M.S., F.A.S.L. (elected in 1854, died 12th December, 1881), was the eldest son of the late Mr. Anthony Brady, of the Royal William Victualling Yard, Plymouth, by his marriage with Marianne, daughter of Mr. Francis Perigal. Born in 1811, he entered the Civil Service of the Navy as a junior clerk in the Victualling Yard, Deptford, more than fifty years since. After serving in various offices, he became head of the Contract Office and Registrar of Public Securities in 1854, subsequently assisting to reorganize that office. He was subsequently appointed first super- intendent of the Purchase and Contract Department, retiring from the service in 1870, when he received the honour of knighthood. After his retirement, Sir Antonio took a leading part in the preser- 900 3 OBITUARY. vation of Epping Forest for the people, and was appointed a judge in the “ Verderer’s Court for the Forest of Epping.” He was a great and able collector of the osseous remains of the great post-pliocene mammalia, and was a member of the Geological and other Societies. He married, in 1837, Maria, eldest daughter of the late Mr. George Kelner, of Ipswich, by whom he leaves a son, the Rey. Nicholas Brady, M.A., and two daughters. Ricuarp Cuewmn Grirrits, M.R.C.S., F.R.G.S., F.Z.8., M.R.I. (elected in 1855, died 5th September, 1881), had at the time of his death attained the great age of ninety years (less three days). He passed his examinations in 1812 and 1813, and was among the first batch of ‘general practitioners.’ He took his father’s practice, in Tottenham-court-road, then a country suburb of London, and after a few years removed to Gower-street. He is described as having “belonged to the old school of practical medicine, and despised theories.” He was the father of the Apothecaries’ Society, of which company he was the Master about twenty-six years ago. For several years the late Mr. Charles Brooke, of the Westminster Hospital, was his partner. Witram Moernte (elected 1866, died 13th December, 1881, aged 53). Mr. Moginie from early youth took great interest in micro- scopical and other scientific pursuits, and as an amateur was one of the first to produce micro-photographs, some of which have never been surpassed. He also made several improvements in the instru- ment, the chief being the ‘ Moginie Travelling Microscope, one of the most convenient of portable Microscopes. Besides being well known as a practical optician, possessed of great mechanical ingenuity, Mr. Moginie was especially noted as a demonstrator, there being few who could exhibit an object with equal skill as regards definition and illumination. Microscopists have lost a prominent and valued member, and his considerable circle of acquaintances a kind and warm friend. James Tennant, F.G.S., F.C.S., F.MLS., F.Z.S., was one of the original Members of the Society, having been elected in 1840. He was for many years Professor of Geology and Mineralogy in King’s — College, London, and subsequently held the Mineralogical chair. He was Mineralogist to the Queen, and a Fellow of many of the learned societies, and was highly appreciated as a mineralogist. He formed a large collection of minerals, and took a great interest in science generally, endeavouring to connect one of the City companies with the movement in favour of technical education. (901) PROCEEDINGS OF THE SOCIETY. Meerine or 11TH Ocroser, 1882, ar Kina’s Cotitean, Stranp, W.C., Tue Prestpent (Proressor P. Martin Dunoay, F.R.S.) mw THE CHAIR. The Minutes of the Meeting of 14th June last were read and confirmed, and were signed by the President. The List of Donations (exclusive of exchanges and reprints) received since the last meeting was submitted, and the thanks of the Society given to the donors. From Dippel, L.—Das Mikroskop, &c. ler Theil, le Abtheil. 2nd ed., viii. and 336 pp. and 189 figs. (Svo. Braunsch- MOL LOSU) way usceh Mein lint woh ok ica whee Stal geste The Author, Dodel-Port, A. and C.—Anatomisch-physiologischer Atlas dersbotanikc pe bantiGn tenn) tise reel prcth ysitap ten Ee ce The Authors. English, J. L.—A Manual for the Preservation of the larger Fungi, &c. viii.and 41 pp. (8vo. Epping, 1882) .. Mr, Crisp. Micrographic Dictionary. 4thed. Parts 13-15 .. .. .. Mr. Van Voorst. Mr. Stewart called the special attention of the meeting to Dr. Dodel-Port’s diagrams (in continuation of the series), which were not only executed with admirable effect, but were also exceedingly correct and of great use for the purposes of the lecture-room. Mr. Beck exhibited a slide of Bacillus tuberculosis prepared by Dr. H. Gibbes by the new process he had devised (see p. 895). Mr. Beck also exhibited and described a new “Lithological Microscope ”’ (see p. 847). Mr. Stewart thought that whilst there were many admirable points about the instrument, yet that, in use, the movement of the polarizing prism might work loose in course of time through being on a hinge joint, and he suggested that it would be found an improvement to have an arrangement shifting in a plane parallel to the stage. The President said that the subject which Mr. Beck’s Microscope was intended to facilitate—now known as Petrology—was a branch of geology which was of extreme interest and importance, and which had made gigantic strides in recent years, so that there were now many geologists who confined their attention to the examination of rock sections. In the course of such observations, the constant shifting of the prisms was extremely tedious, and some remedy for this was indispensable. The important question was, which of the various methods was the easiest? In looking at the instrument as it stood, he thought that the necessary movement could be effected more easily as Mr. Beck had constructed it than by a lateral movement as suggested by Mr. Stewart. This branch of geological study was, he considered, 2 most desirable one for the Fellows to take up. It in- 902 PROCEEDINGS OF THE SOCIETY. volved a study of optics as well as of geology. There was an idea that such observations could be carried out better elsewhere than in this country, where they first originated ; but he thought that, with the aid of Mr. Beck’s improvements, there would be no difficulty in showing that we were able to investigate the subject, at least as well as could be done anywhere else. Mr. Crisp exhibited and described (1) Gundlach’s College Micro- scope (see p. 670); (2) Boecker’s Air-Pump Microscope; (8) The Bausch and Lomb Optical Company’s Immersion Illuminator (see p- 688) (the latter not, however, being 1°52 N.A. as marked, but about 1:20 N.A.); (4) Thomas’ Vivarium (see p. 688); and (5) a new achromatic spherical pocket lens, by Gundlach (‘“ Globe lens”), which consisted of a sphere of crown glass enclosed in an outer sphere of flint glass. Mr. Ingpen described a method of rapidly attaching objectives to the nose-pieces of Microscopes which had been devised by Mr. E. M. Nelson, the idea having been suggested to him by the method em- ployed by the French for fixing the head-pieces of ordnance (see p. 858). Dr. Ondaatje, of Ceylon, was introduced to the meeting by the President, and exhibited and described a number of specimens of Echinoderms, Gorgonide, Algz, &c., which he offered to the Fellows for mounting. The President, in thanking Dr. Ondaatje for his communication, said that a small specimen of Hchinus was especially curious, as it seemed to him it did not consist of the original carbonate of lime of the creature, but looked more like crystallized calcite, as if it had been concreted in some way. Mr. E. W. Burgess’s letter was read, accompanying specimens of diatoms from the Island of Lewis (see p. 665). Mr. Crisp said it would be in the recollection of the Fellows that, at the April meeting of the Society (see p. 440), a note by Drs. Loew and Bokorny was read, as to the chemical difference between living and dead protoplasm, and that some remarks were made by Mr. Stewart as to the possibility of some of the effects being due to the remains of the citric acid used in killing the protoplasm. Dr. Loew had since written a note in reply to the criticisms, which was then read as follows :— “T learn from the June number of your highly-esteemed journal that the discovery of a chemical difference between living and dead protoplasm by myself and Bokorny has given rise to some discussion in the Society. Mr. Stewart has expressed some doubts in regard to our statement, believing that some residual citric acid (which we had applied in one case of killing the cells) might have been the cause that no silver was reduced. PROCEEDINGS OF THE SOCIETY. 903 In regard to this I have to say that the acid was removed as well as possible by continued washing with distilled water, before applying the silver reagent. Besides, the alkaline nature of the latter would have neutralized any trace of the acid left. The reason why, after killing with citric acid, no more silver was reduced by the cells, was certainly a chemical change of the protoplasm itself. Whoever will take the trouble to study our publication, ‘Die Chemische Kraftquelle im lebenden Protoplasma (The Chemical Source of Power in the living Protoplasm), will find that every precaution was taken in all our labours to avoid errors and false conclusions. We have killed the cells in all possible ways: by starvation, by desicca- tion, by heating to 50° C., by mechanical action, by electrical sparks, by ether, alcohol, carbonic acid, kerosene, sulphuretted hydrogen, by sugar, tannin, by acids, alkalies, and salts; and in all these cases the protoplasm had become changed, so as to be incapable of reducing silver. In one case, however, death was produced by destruction of the structure and organization alone, the chemical nature remaining unchanged ; it was by the action of certain poisons, especially alka- loids. We have described these cases in minute detail in our publication. Life must be considered as the result of two functions :— 1. Of a specific chemical motion—viz. the energy of the aldehydic groups in the molecule of the active albumen. 2. Of the organization of the protoplasm—viz. the specific mole- cular construction from molecules of active albumen. If one of these functions is destroyed, death is the result (see pp. 25 and 77 of our publication). No thinking mind will doubt that the vital force is a mode of motion, like all other forces of nature. We have proved beyond a doubt that the vital force is the result of a specific chemical motion, as minutely explained in our publication (see pp. 19-25 and 88). It is true there are many objects which are so sensitive, that they die too quickly to give the silver reaction, which is only slowly developed, requiring many hours; we have described such cases too (see pp. 60-62 of our publication). I have proved, furthermore, that the quantity of reduced silver corresponds with my theory (see pp. 91, 92), and have arranged now to analyze the product formed by the action of the silver solution upon the living protoplasm; a product that it is impossible to obtain with dead protoplasm. In regard to Mr. Stewart’s remarks on ‘ silver-staining,’ it is most essential to note that the silver-staining process is based upon the action of light ; many organic substances will reduce silver, if in con- tact with light. Our process, however, goes on in absolute darkness ! and is quite a different thing from the ‘ silver-staining process.’ Recently some volatile aldehydes have been discovered in plants by Mori and by Reinke; but we must utterly deny that our observa- tion has anything to do with such an aldehyde. Our objects were entirely free from any volatile or soluble aldehyde ; hence our reaction shows conclusively the aldehydic groups as constituent parts of the molecule of active albumen. The albumen, passing from the active 904 PROOEEDINGS OF THE SOCIETY. into the passive condition, loses the aldehydic groups by displacement of the atoms (‘ Atomumlegerung’) and the intense chemical motion has ceased herewith at once.” Mr. Stewart said that the remarks which he made on the occasion referred to were hardly offered as a matter of criticism, but rather by way of inquiry. It was clear that the experiments of the authors had been conducted with singular precision, and he was very glad that his observations had been the means of bringing out these additional particulars. He might also say that the original paper of Drs. Loew and Bokorny having been sent to him, he had laid it before Dr. Bernays, the chemical lecturer at St. Thomas’s Hospital, who had been so much interested in the subject that he intended to thoroughly investigate it, and no doubt they would in due course hear the results of his experiments. Meanwhile, as a preliminary, he had received from him the following letter :— ‘“‘T have read the letter of Drs. Loew and Bokorny, and consider as proved by them that the power of producing alkaline silver solu- tions is an essential property of many forms of living vegetable plasma. I consider that a complete answer is furnished to your own suggestion about residual citric acid: that must be given up. The experiments of Drs. Loew and Bokorny have been made with a care and skill deserving of the highest praise. Of the nature of animal protoplasm little is known. The authors of ‘Die Chemische Kraftquelle im lebenden Protoplasma’ admit as much; but they consider themselves entitled to the judgment that the reactions of aldehyde groups in active albumen are capable of equal application. The cases of chronic silver-poisoning do not seem to confirm the view, as we should certainly expect on the aldehydic theory a much more even distribution of metallic silver. And, in the case of man, alcoholic potations would have to be rigidly excluded in order to assist in the confirmation, or otherwise, of the aldehydic theory. Whether any, and what, differences exist between vegetal and animal albumens we cannot exactly say. The aldehydic theory is the most interesting attempt at explaining the distinction between living and dead protoplasm that has ever been offered. But, although the reactions discovered by Drs. Loew and Bokorny are similar, in the one aspect of reducing alkaline silver solutions, | do not see more in their most interesting statements. of experiments and views than to confirm most successfully the differ- ence between living and dead plasma. For myself, I say, with all deference to these distinguished scientists, that further proof must be offered of the view these gentlemen hold, before I would accept the aldehydic theory as more than an interesting attempt at explana- tion.” ee Mr. Crisp read a note from Mr. C. Stodder as to the Tolles }-inch objective with tapering front, exhibited at the June meeting (see p. 589), in which the writer pointed out that the speakers at that meeting, who stated that “similarly tapered” objectives had been made as early as 1848 by Andrew Ross, and since by others, had not understood “the peculiarity or the purpose of the construction of the PROCEEDINGS OF THE SOCIETY. 905 objective exhibited. It is not merely an objective of the usual form in a tapering or conical brass mount, but the front lens is itself a cone.” No such objective had ever been seen in America previously to that first made by Tolles in May 1870, and there is no record of any having been made in England or anywhere else. Mr. Ingpen said he was now able to exhibit the objective he referred to at the last meeting by Andrew Ross. Its aperture was 60°, and the front lens, which was a triplet ,3, inch in diameter, was coned down to an angle of 120°, reducing the front to 5 inch surface. Opaque objects could be illuminated at an angle of 30° from the level of the slide. The primary reason for coning this particular objective was the use of a very narrow Lieberkiihn, but objectives were also coned for the purpose of getting rid of “stray light,” to which par- ticular attention was afterwards called in an article by Mr. Wenham on angular aperture, published in 1874, after which many lenses were coned for that purpose. The practice had since been to a great extent abandoned, in consequence of the reduction of aperture caused by it. Mr. Beck said it was quite preposterous for any one to suggest that there was any novelty whatever about the objective referred to by Mr. Stodder. James Smith, who was a very skilful worker in glass, used to pride himself upon the way in which he was in the habit of coning down object-glasses. He used to fit them in a cell, and then turned them down in a lathe with a diamond, so that the front lens had no cell at all. A small brass cap was fitted over it to prevent any danger of its being injured. Dr. Edmunds said that the Fellows always cordially welcomed communications from foreign microscopists. It was true that it had been demonstrated this evening that the idea of coning off the front lens of an objective had been tried long since by English opticians, and therefore that the plan communicated by Mr. Stodder was not new; but he thought Mr. Tolles was evidently entitled to the merit of an independent invention. These discussions over devices tried and lost sight of, only to be reinvented a generation later, showed the value of the figures and technical descriptions of apparatus which had been published in the Society’s Journal of late years. He asked if Mr. Beck or Mr. Ingpen could give the meeting any references to previous descriptions of the method. Mr. Beck said it was recorded in the catalogues of their firm; and if any other evidence was needed, it might be found in the fact that a large number of microscopists were in possession of similar objectives. Mr. Beck then examined the Society’s Cabinet, and pro- duced one of James Smith’s objectives, made before 1847, the front lens of which was coned off in the manner described, and a small cap put over it. Mr. J. Mayall, jun., said he understood Mr. Stodder’s claim on behalf of Mr. Tolles to be that he originated the plan of reducing the front lens or lenses of an objective, as near as possible to the cone of light transmitted, so that the exposed surface of the front lens was the exact working diameter required for the aperture of the whole combination. By such acute coning no doubt the greatest range was 906 PROCEEDINGS OF THE SOCIETY. provided for the use of Lieberkiihns, &c. He had examined many low-power objectives with tapering fronts, but the great majority were seen at a glance to have been coned with no other purpose in view than to improve their appearance. With regard to the Ross 1-inch objective of 60° air-angle, exhibited by Mr. Ingpen, of which the body of the front lens was coned to an angle of 120°, it was evidently not Andrew Ross’s intention to cone the front to the uttermost, or he would have cut it down to an angle of about 40° instead of 120°: 40° in the body of the crown-glass front being sufficient to transmit a pencil of 60° from air. Could Mr. Beck affirm that the objective he referred to, made before 1847, was coned in front so as to allow just the full aperture to be utilized? If so, he (Mr. Mayall) thought Mr. Stodder’s case must fall to the ' ground. a Mr. Beck said that the one he held in his hand was done with the precise object of getting the front reduced to the smallest cone possible. Dr. Dippel’s note “Correction-Adjustment for Homogeneous- Immersion Objectives,” was read by Mr. Crisp (see p. 854). Mr. Beck said that the paper seemed to him to be an apology for being content with inferior definition rather than taking the trouble to get the best that was to be obtained. He understood the course of argument to be that there was so much trouble in making the adjust- ment that it was better to do without it. He ventured to say that there was not any one who had got over the trouble who would for a moment put up with what was inferior, if he had it in his power to get what was the better. He should like to hear some observations on this subject from Mr. Mayall. Mr. Crisp said that the author of the paper did not put the matter on the ground of trouble at all. What he said was that the advan- tages to be derived from the adjustment-collar were so infinitesimal in the case of unknown objects, that they did not compensate for the disadvantages. Mr. Ingpen thought that even amongst those who were thoroughly familiar with the use of the highest powers, very few would be found capable of adjusting an objective to the same degree of accuracy as the optician, and therefore any one who had a valuable objective should be very careful not to disturb its correction. It was also, he believed, a matter of experience that with the particular class of objects referred to by Dr. Dippel, no two histological observers would agree as to the best correction. Professor Abbe had met that difficulty by proposing a special test-object for the purpose, and as the descrip- tion of this method would, he understood, shortly appear in the Journal, he need not enter further into that part of the subject, except to say that the Professor’s test-plate was not like the Podura scale or P. angulatum, but showed beyond question what the best correction was, and made it possible for a person to pass a number of eee under the objective, and at once determine the best correction or each. Mr. J. Mayall, jun., said he concurred in much that Mr. Beck had PROCEEDINGS OF THE SOCIETY. 907 said, especially in his advocacy of all that tended towards the perfec- tion of objectives. As regarded the application of the correction- adjustment to homogencous-immersion objectives, he was obliged to express his disagreement with Dr. Dippel. The facts on which his own judgment on this question was based were briefly these:—When Zeiss’s homogeneous-immersion objectives were first sent to England, he immediately observed that certain dry objects, such as Podura, were very indifferently defined by the new lenses, precisely as he had previously found with water-immersions in fixed settings. These objects were always such as did not adhere very closely to the cover- glass. Knowing from.experience that the correction-adjustment had, in many cases, met the difficulty with water-immersions, he took an early opportunity of pressing upon Messrs. Powell and Lealand to apply the adjustment to the homogeneous-immersions. The result fully answered his expectations. There could be no doubt whatever that the correction-adjustment increased the range of conditions within which the homogeneous-immersions would give fine definition. He might state, as a matter of repeated personal experience, that in testing a number of homogeneous-immersions—fixed settings versus adjustment settings—whilst there were undoubtedly many prepara- tions which were defined equally well by both systems, there were also many upon which no superficial structure could be discerned with the objectives in fixed settings, but which yielded well-defined images when viewed with objectives having the correction-adjustment. The differences in the lenses might not be so marked as those seen in comparing dry lenses with and without adjustment; but still they were unmistakable, and unquestionably in favour of the adjustment. In the best homogeneous-immersion objectives he had examined, the corrections were so sensitive that different thicknesses of cover-glass had to be compensated for by the adjustment; whilst different speci- mens of oil of cedar-wood so completely altered the character of the image, that unless the correction-adjustment were brought into use, the objective might be condemned as defective. Even with the cor- rection-adjustment, a marked variation from the normal immersion- fluid could not be compensated for. The objectives he here referred to were those of apertures from 1°2 to 1:47. He could not agree with Mr. Ingpen that it was best for the amateur to let the opticians choose for him the best average adjustment, and there fix the lens- mounting. He considered the amateur should make himself skilled in the use of the adjustment. As to the difficulty of finding two persons who would agree on the best point of adjustment in attempting to interpret an image of an histological preparation, he thought the solution of the difficulty would be best found by ensuring greater skill in making the preparation. When the Bacillus tuberculosis was first observed, it was only after great perseverance that anything could be interpreted from the confused mass of images; but the moment better methods of treating the preparations were found, the difficulties vanished, and what had formerly required hours of patient investiga- tion to glimpse was now exposed to the eye at a glance. It would be interesting to the Society to learn that Prof. Abbe himself had so far wavered from his former opinion against the application of the cor- 908 PROCEEDINGS OF THE SOCIETY. rection-adjustment to homogeneous-immersions that he now agreed with Dr. Zeiss that those objectives should be supplied either with or without adjustment; accordingly, in future, both kinds would be supplied. He gave this on the authority of Dr. Zeiss. Prof. Abbe must therefore be regarded as partially, at least, opposed to Dr. Dippel’s views. He might add that, among the opticians who were in favour of mounting homogeneous-immersions with correction-adjustment, were Powell and Lealand, Ross, Schroeder, Spencer, and Tolles. Mr. Crisp said that Dr. Dippel did not dispute that a somewhat higher degree of accuracy might be obtained with the correction- collar, but it was only with known objects, such as the Abbe test- plate, and with the closest examination. With unknown objects, however, he considered it was utterly impossible to determine the position of best correction, and the correction-collar had, therefore, in those cases, no advantage to compensate for its disadvantages, and should not be used by histologists at any rate. Mr. Crouch said that, in making the rough adjustments for students’ Microscopes, they had to bear in mind the purposes for which they were likely to be used. In ordinary cases they would have to provide for histological sections, and this was not an easy matter, being quite unlike the case of a Podura scale, where they could adjust properly, because they had a surface to focus upon. He found the best average results were obtained from an objective when it was adjusted for an average thickness of cover-glass. He had known cases. in which objectives with correction-collars had been condemned and returned to him, because it was said that good definition could not be got, the same objective being pronounced satisfactory after being remounted in a fixed setting. Dr. Edmunds thought that adequate weight had not been given to the difficulty of ascertaining what was the true image of a complex histological section when viewed under a high-power objective. ‘The real question was whether that image could be most certainly fixed upon by means of a lens furnished with a correction-collar, ne- cessitating its adjustment for each object. Microscopists who devoted themselves to the resolution of Amphipleura pellucida, or of Nobert’s lines, often knew nothing of the difficulty of interpreting the structure of muscular fibre and other more complex histological objects. The Podura-scale, though used as a test-object for histological lenses by their makers, yet was an object whose structure had never yet been interpreted in any way which commanded general assent. Take, again, Pleurosigma formosum in balsam, which presented different appearances with every touch of the correction-collar and with every variation in focal distance, so that it could not be interpreted with certainty ; were a skilled microscopist now to see this object for the first time, a correction-collar upon his homogeneous lens would only add to his difficulties in fixing upon what was its true image. With a water-lens and varying thickness of cover-glass, the case was different, and the correction-collar was indispensable. While, there- fore, the correction-collar might be theoretically an advantage, he thought that in practice it would be a disadvantage, and that, instead PROCEEDINGS OF THE SOCIETY. 909 of attempting to correct the objective, we should correct the object by mounting it always under conditions defined as those of homogeneous immersion. Mr. Guimaraens called attention to a slide labelled “ Pedicellariz in situ, attached to the spine of Echinus gracilis,” and sold as illus- trating a discovery that pedicellariz are attached to the spines of Echini. He would be glad to. know whether the pedicellarie in question were naturally attached to the spine, or whether an im- position had been practised. Mr. Stewart said that in this specimen the pedicellariz were un- doubtedly adherent; but they could not have been so during the life of the animal. The following Instruments, Objects, &c., were exhibited :— Mr. Beck :—(1) Slide of Bacillus tuberculosis prepared by Dr. H. Gibbes. (2) New Lithological Microscope. Mr. E. W. Burgess: —Diatoms from the Island of Lewis. Mr. Crisp :—(1) Gundlach’s College Microscope. (2) Boecker’s Air-pump Microscope. (3) The Bausch and Lomb Optical Co.’s Immersion T]luminator. (4) Thomas’s Vivarium. (5) New Achro- matic Spherical Pocket-lens by Gundlach ( “ Globe lens” ). Mr. Guimaraens :—Slide labelled “ Pedicellariz in situ attached to spine of Echinus gracilis.” Mr. Ingpen :—(1) Nelson’s Nose-piece Adapter. (2) Objective of Andrew Ross with tapering front. Drs. Loew and Bokorny :—Twelve slides illustrating their views on the chemical difference between dead and living protoplasm. Dr. Ondaatje :—Specimens of Echinoderms, Gorgonide, Algzx, &. Meeting or 8TH November, 1882, ar Krne’s CoLtzcr, Stranp,W.C., Tue Present (Proresson P. Marrin Dunoan, F.R.S.) in THE Cuarr. The Minutes of the meeting of 11th October last were read and confirmed, and were signed by the President. The List of Donations (exclusive of exchanges and reprints) received since the last meeting was submitted, and the thanks of the Society given to the donors. From Braithwaite, R.—The British Moss Flora. Part 6 ee The Author. Deby, J., and Kitton, F.—A Bibliography of the Microscope and Micrographic Studies, being a Catalogue of Books and Papers in the Library of J. Deby. Part 3. The Diato- ENA CAD ce Eee TMeT en ase, Foch. ‘esl es 58) ele fo Mr. Deby. Saurel, L.—Du Microscope au point de vue de ses applica- tions & la connaissance et au traitement des Maladies Chirurgicales. 148 pp. (8vo. Paris, 1857).. .. .. Mr. Crisp. Six slides of ovaries, &c., of plants .. .. .. .. « «+ Mr. Krutschnitt, Five slides of Diatoms mounted from the materials sent by Mr, W.F. Petterd from Tasmania .. .. 0.5 sv Mr. Kitton. Ser. 2.—Vot. II. 3p 910 PROCEEDINGS OF THE SOCIETY. Mr. Collins exhibited a portable form of his histological Micro- scope, the special feature of which was the folding-up of the heel- piece of the tripod. Mr. Curties exhibited several of Zeiss’s pocket and dissecting microscopes. Mr. Crisp exhibited and described (1) Guillemare’s School Microscope (see p. 669) and (2) Prof. Abbe’s Refractometer, for readily ascertaining the refractive index and dispersive power of fluids to be used for homogeneous immersion. Mr. Krutschnitt’s (New Orleans) six slides, four of which were sections of the ovaries of plants, were exhibited in support of the author’s view of the fertilization of the ovule. _In the letter accompanying them, the writer said “the sections of the ovaries may go to show that the theory of the fertilization of the vegetable ovule by means of the pollen-tubes requires overhauling. See Amer. Mon. Micr. Journ., June 1882.” Dr. Maddox exhibited photographs of microscopical objects, printed by the platinotype process, which he found very suitable for scientific work, the paper being of fine texture, and capable of giving minute detail. (See Brit. Journ. of Photography, Sept. 15th, 1882.) He also exhibited aud described some new forms of warm and moist stages, which he exhibited in the room, and further explained by means of diagrams. The President said that the stages were very simple, and very easily used, and would doubtless be of great use in examining blood and other objects, which it was desired to keep at an even, warm temperature. Mr. J. W. Groves exhibited and described his improved ether- freezing microtome (see p. 755). Mr. Stewart said that his own experience was that the ether method of freezing was a great advantage, for the full range of temperature was at command. It was only necessary to take care that the freezing was not overdone, so as to make the subjects brittle. A little practice enabled a person to control the temperature at will. Mr. Kitton’s note was read describing the results of his examina- tion of the diatom material, sent by Mr. W. F. Petterd from Tasmania, which contained several interesting forms, but no new genera or species. Mr. T. B. Rosseter’s paper “Researches on the Life-history of Stephanoceros Eichornii,’ was read, and illustrated by drawings enlarged on the black-board. Mr. Crisp said that the author of the paper was worthy of every possible encouragement and commendation, as his observations were ‘PROCEEDINGS OF THE SOCIETY. 911 carried on under the greatest difficulties, and much credit was due to him for the indefatigable way in which he pursued them. The President thought the paper was a very admirable one, what- ever difference of opinion there might be as to some of the points touched upon. Mr. T. C. White said that he was under the impression that as far as the attachment of the ovum to the parent was concerned, it was really attached to the case. The gelatinous envelope could hardly be called a case in the sense of being a thin structure, but it was rather a thick tube with solid walls, and when the creature retracted itself, the portion of the tube to which the ovum was attached was carried down with it. As regarded the viviparous character mentioned, he had observed it in Rotifer vulgaris, and had also noticed the fact that the parent died as Mr. Rosseter described. Mr. Badcock having had an opportunity of previously reading the paper, read some critical remarks which he had written as to the question of the tube being “ solid ” or not. Mr. Beck thought that the paper was an exceedingly interesting one, and after the remarks which had been made by Mr. Crisp as to the circumstances under which the observations had been made, it was doubly interesting. The way in which the writer had combined observation with experiment, and the manner in which he described the results, was, he thought, very creditable indeed. The fact of the creature making its way out of the cell, not at the top but at the lower end, was very interesting, for it would be natural to suppose that if any injury had taken place it would have escaped in the opposite direction. It occurred to him that this circumstance might afford a clue as to the way in which these objects expanded. Mr. Michael thought that to a certain extent the question of an attachment to the tube was a substantial one, but whether the case was solid or tubular was more a matter of words. Pritchard could not mean that a cylinder in which a creature moved up and down was really “solid”; what he meant was probably that, instead of being a mere thin shell, it had a considerable thickness approaching towards solidity. The dragging down of the ovum, he thought, commenced before the arms touched the tube. The President said it appeared to be quite clear that the tube had a considerable thickness, and that the attachment or adhesion to it was by the base only. With regard to the curious twisting round of the animal to get out at the lower end, it should be remembered that these creatures were Vermes, and that this was just the kind of thing a worm would do under the circumstances. He quite agreed with Mr. Beck in his remarks on the paper, and he hoped they would have more of the same kind. Mr. Crisp made some remarks on the criticisms that had been passed on the paper. Dr. Maddox read a paper on “Some Organisms found in the Excrement of the domestic Goat and the Goose” (see p. 749). 912 PROCEEDINGS OF THE SOCIETY, Mr. Geldart, the President of the Norfolk and Norwich Naturalists’ Society, one of the ex-officio Fellows of the Society, was welcomed by the President. Mr. Gelda:t said he was greatly obliged to the Fellows for the welcome given to him, and could only express the gratification which it afforded him to be present. He also wished to take advantage of the opportunity to thank them, in the name of his Society, for the privilege afforded to them of receiving the Journal of the Society, and profiting by the very admirable summary which it contained of all that was being done in microscopy, both at home and abroad. Mr. Geldart then called attention to a slide of Globigerina which he had brought, with all its spines im situ—so unusual an object that it seemed to be worth bringing for exhibition. It was obtained by the ‘ Challenger.’ The President inquired whether it came from the surface. Mr. Geldart said that this, and, indeed, all those, few in number, which had been obtained, came from the surface. Those brought up from the floor had the spines dragged off by the towing net. He had never seen more than two. The President said that in examining some deposits from 14,000 feet he found them crammed with Globigerine, amongst which he had the good fortune to find one with spines. He was very glad to have seen this specimen as being an original from the ‘ Challenger’ expedition. The Conversazione was announced for the 6th December. The following Instruments, Objects, &c., were exhibited :— Mr. C. Collins :—Portable Histological Microscope. : Mr. Crisp:—(1) Guillemare’s School Microscope. (2) Abbe’s Refractometer. Mr. Curties:—Simple and Dissecting Microscopes by Zeiss. Mr. Geldart :—Globigerine from the ‘ Challenger.’ Mr. Groves :—New Ether-freezing Microtome. Mr. Joshua :—Triploceras tridentatum (New Zealand Desmid). Mr. Kitton :—Five slides of Diatoms from Tasmania. Mr. Krutschnitt :—Six slides of ovaries, &c., of plants. Dr. Maddox :—(1) Photographs printed by the platinotype process. (2) Warm and Moist Stages. New Fellows :—The following were elected Ordinary Fellows :— Messrs. Joseph Ball, Cornelius Van Brunt, Walter A. Dun, George E, Fell, James D. Hardy, David Houston, William A. Lee, Clermont Livingston, George M. Sternberg, and Frederick A. Whaite. Water W. REEvEs, Assist.-Secretary. ( 913 ) PN D'Eex: ——4——— *.* The Index includes the names of the Authors of all Papers, &c., printed in the “'Transactions ” or noted in the “ Summary,” as well as those of the Designers of any Instruments and Apparatus described under the head of “ Microscopy.” A. Abbe, E., 551, 559, 693. — Camera Lucida, 261, 593. Condenser, 411. — The Relation of Aperture and Power in the Microscope, 300, 460. — Theory of Microscopical Vision, 147. Abortion of Reproductive Organs of Vitrina, 330. Absorption, Cutaneous, Want of, in Aquatic Coleoptera, 771. of Metallic Oxides by Plants, 526. Acalephe, American, 634. Acari, Insecticolousg, 774. Accessories, Instruments, &c. tents. Account, the Treasurev’s, 292. Acids, Vegetable, Prevention of Fer- mentation by, 833. Acinetide, 636. “ Acme ” Class Microscope, 251. Actinie, Andres’ Method of treating, 881. ——, Ovaries of, 795. —, Sense of Smell in, 635. , Vital Phenomena of, 794. Actinophrys sol, 800. Adapter for Rapidly Changing Ob- jectives, Nelson’s, 858. Address, the President’s, 145. Adjustment, Deby’s Screw-collar, 107. Adolph, G. E., 35. Adoxis Vitis, Development of, 39. Adriatic Bryozoa, New, 494. Adventitious Buds on the Lamina of the Frond of Asplenium bulbiferum, 226. Aiquorea, Development of, 515. Aeration of Aquaria, 131, 286. Aerial Cultivation of Aquatic Plants, 930. Organs, Order of Appearance of the Primary Vessels in, 812. AXthalium septicum, Composition of the Protoplasm of, 362. Ser. 2.—Vot. IT. See Con- Agaricini, 825, Air and Light, Influence of, on the Anatomical Structure of Plants, 651. Air-bubbles and Fat-globules, ~Ap- pearances presented by, in White and Monochromatic Light, 742. * Alkakia,” 685, Aktinomykosis, New Fungoid Cattle Disease, 236. Alcyonaria, Development of, 797. Aldehydes, Occurrence of, in Chloro- phyllaceous Plants, 361. Alge. See Contents. Allantoin, Occurrence of, Vegetable Organism, 223. in the Allen, F. J., 435. 5 Gry SAL. — , T. F., 535. “ All-round Vision,” 157. Alternation of Generations in Doliolum, 331. in Hypodermiz, 827. in Uredinee, 80. Ambronn, H., 71, 227. Ambulacral Tubes of the Regular Kchinoidea, Spicules found in, 297. American Acalephe, 634. —— Association, Section of Histo- logy and Microscopy at, 119. — Cephalopods, 604. — Comatule, 199. —— Crustacea, 617. Ames, D. T., 727. Amecebe, Contributions to the Know- ledge of, 208. —— and Infusoria, Preserving, 574. Ameeboid Movements, Theory of, 319, Amphineura, Morphology of, 331. Amphioxus, Development of, 174. Amphipleura and Pleurosigma, Wood- ward’s Photographs of, 727. — pellucida, Resolution of, 584. Ampullz, Pyloric, of Podophthalmate Crustacea, 505. Amyloid Deposits and Chlorophyll Corpuscles of Spongilla and Hydra, 322. 3Q 914 Amyloids, Digestion of, in Cephalo- poda, 30 Andree, J., 48. Andres, A., 57. — Method of treating Actiniz, 881. Angiosperms, Embryo-sac of, Free-cell formation in, 214. Anguillula stercoralis, Development of, il Anilin Dyes and Vegetable Tissues, 281. —— -green and Carmine, Double Staining with, 576. Animalcula, Minute, Continuous Ob- servations of, 731. Ankylostoma duodenale, Anatomy of, 781 Annelid, Coral Reef, 621. ——, Synthetic, 778. Annelids and Vertebrates, Spermato- genesis in, 316. — , Aphroditacean, Elytra of, 779. —, Development of, 618. —, of Central Nervous System of, 619. ——, Origin of the Central Nervous System "of, 44, ; Swim- bladder-like Organs in, 44. Annuli and Lines, Black, of Spherules and Threads, 696. Anon., 288, 728, 834. Anthers, Preparing, 122. Anthony, J., 129. —— On the Threads of Spiders’ Webs, 170. Anthozoan Fauna of Naples, Prodrome of, 57. Anthrax, Duration of Immunity from, 239. , Infection by Symptomatic, 236. Vaccination, Experiments on Pas- teur’s Method of, 238. Antipodal Cells, Functions of, 64. Ants, Occident, 333. Aperture and Power in the Micro- scope, Relation of, 300, 460. , Large and Small, Relative Value of Objectives with, 157. , Objectives of small and large, 853. of Objectives, 149. —— —, Diaphragms for Limiting, 407. gare —, Iris-Diaphragm for varying, 62. * Aphaneri,” 250. Aphis, Willow-tree, Colouring Matter ~ from, 39. Apical Cell and the youngest Seg- ments, Energy of Growth of, 67. INDEX. Ape Cell Growth in Phanerogams, 523. Growth of the Roots of Phane- rogams, 650. Apocynacez, Fertilization of, 215. Apostolides, N., 199, 789. Apothecia of Lichens, Structure and Development of, 388. Appearance of the Primary Vessels in Aerial Organs, Order of, 812. Aquaria, Aeration of, 131, 286. Aquatic Animals, Saline Constituents of the Blood of, Influence of the Ex- ternal Medium on, 763. — Plants, Aerial Cultivation of, 530. Arachnida. See Contents. Arcangeli, G., 544. | Areolations of Isthmia nervosa, 129. Aril of Ravenala, 216. Arloing, 236. Artemia salina, Germs of, 43. Arthropoda. See Contents. Artificial and Natural Objects, Defini- tion of, 420. Ascidian Ova, Test-cells in, 491. Ascidians, ‘ Challenger,’ 182. , Organization and Development of, 180. Ascomycetes, Epiplasm of, 824. —, Rehm’s, 378. Asplenium bulbiferum, Adventitious Buds on the Lamina of the Frond of, 226. Assimilating Tissue, 368. Assimilation, Determination of the Activity of, by the Bubbles given off under Water, 223. —, First Products of, 526. ——,, History of, and of the Functions - of Chlorophyll, 525. —, Theoretical View of the Process of, 525. Asterias, 56. ——., Genital Passages of, 348. —— glacialis, Variation in, 513. Asterina gibbosa, Development of, 628. Asteroidea, Spines of, 57. Asteroides, Development of Calcareous Skeleton of, 514. | Atlas of the Diatomacez, Schmidt’s, 249. Atmospheric Bacteria, 88. Atwood, M., 735. Atyoida Potimirim, Adaptation of Limbs in, 42. Aubernage, a Disease of the Vine, 827. Avicularia in Bryozoa, Modifications of, 183. Axis-cylinder, Preparing Sections of, 03. INDEX. Azolla caroliniana, Biological peculi- arity of, 227. , Prothallium and Embryo of, 76. B. B., T. R., 585. Babes, V., 541. Bacilli of Hay and of Distemper, Con- nection of, 657. ——, Specific Connection of Diseases with, 89. Bacillus, Pathogenous, in Drinking- water, 89. tuberculosis. See Bacteria. Backgrounds, 559, 565. Bacteria, Atmospheric, 88. — , Biology of, 380. —, Collecting, Staining, and Photo- graphing, 571. —, Connection of, with Ferments, 541. ——, Diastatic Ferment of, 829. ——, Diffusion of, 658. ’ — of Caucasian Milk Ferment, 383. — of Davaine’s Septicemia, 310. — of Distemper, Experimental Pro- duction of, 832. — of Intermittent Fever, 830. — of the Cattle Distemper, Experi- mental Production of, 382. — of Tuberculosis, Ehrlich’s Method of Exhibiting, 572. —— ——, Preparing, 706. —— ——, Staining, 895. — Pathogenous, 541. , Properties and Functions of, 88. Bacterial Parasite of the Chinch Bug, 830. Bacterium, New, Sensitive to Light, G56, — of Charbon, 541. —— rubescens Lank. = Monas Okenii Ehr., 640. Badcock, J., 345, 512, 594. Baillon, H., 649. Bainier, G., 80, 661. Se oelosus, Systematic Position of, Balbiani, E. G., 185. Bale, W. M., 581, 582, 583, 720. Balfour, F. M., 23, 314, 316. Balsam and Carbolic Acid, Mounting Histological Preparations with, 425. , Mounting in, 126. —, —— in Pure, 717. ——, — Moist Objects in, 582. ——,, substitute for, 898, Baltic, Diatoms of, 837. Barbieri, J., 223. Barfi’s (F. 8.) Preservative for Organic Substances, 124. 915 Barnard, F., 583. Barrois, J., 182, 492. Bary, A. de, 230. Basevi, Col., 435. Batalin, A., 72. Batrachospermum, 544. Baumann, T., 420. Bausch and Lomb Optical Co.’s Circle Cutter, 285. Excelsior Pocket and Dissecting Microscope, 401. Fine Adjustment, 683. —— Glass Stage and Slide-carrier, 687. —— Handy Dissecting Microscope, 400. — — — — Immersion Illu- minator, 412, 688. —— —— —— —— Paraboloid, 412. —_ —_——_ — Professional Micro- scope, 666. — — — — Standard Self- centering Turntable, 434. — — — — Trichinoscope, 258. —_— — — — Turntable, 434. Bazley, T. S., 117. Bedot, M., 204. Beck’s Achromatic Condenser for Dry and Immersion Objectives, 270. —— Histological Dissecting Micro- scope, 852. Lithological Microscope, 847. Bee, Parthogenesis in; 608. Beggiatoa, New, 544. Behrens, T. H., 736. Beling, 772. : Bell, F. J., 56, 57, 513, 788, 791. —, Note on the Spicules found in the Ambulacral Tubes of the Regular Hehinoidea, 297. Bellesme, J. de, 41. Bellonci, J., 770. Beltrania, a New Genus of Hyphomy- cetes, 538. Benecke, B., 23. Beneden, E. van, 180, 621. Berggren, 8., 76. Bergh, R. §., 351, 355. Berlese, A., 774. Bernays, 904. Bertkau, P., 39. Betzold, F., 83. Beyerinck, W., 500. Bibliography. See Contents, Bilbarzia hematobia, Proscolex of, 51. Binocular Arrangements, Non-stereo- scopic, Stereoscopic Vision with, 271. — Microscopes, 253, 416. —— Prisms, Nose-piece for, 684. 3 Q 2 916 Binocular Vision in the Microscope, 692. Binz, O., 234. Birds, Photographs of the Develop- mental Process in, 23. Birge, H. A., 428. Bismarck Brown, Staining Living Pro- toplasm with, 278. Bizzozero, G., 480. Blaas, J., 741. Black Annuli and Lines of Spherules and Threads, 696. Backgrounds, 559. Blackham, G. E., 407. Blastoderm of the Chick, Preparing, 570. Blind Subterranean Crustacea in New Zealand, 778. Blood-corpuscle, New, 480. , Nucleated, Differential Stain- ing of, 714. , White, 27. — of Aquatic Animals, Saline Con- stituents of, Influence of the Ex- ternal Medium on, 763. —— of the Crustacea, 504. Blue Glass Slides, Mauler’s, 142. Board, Spring-Clip, 128. Boecker’s (H.) Microtome, 893. Boehm, J., 373. Bohm’s Wool-measurer, 859. Bokorny, T., 67, 361, 440, 522, 902. Books, Insects which Injure, 500. Bopyride, 188, 338. Bordered Pits, Development of, 523. Boring Sponges, 516. Bornet, H., 93, 835. Borodin, J., 815. Bossy, F., 94. Botany. See Contents. Bouchon-Brandely, 606. Bouley, 237, 238. Bourne, A. G., 567. Bourquelot, H., 30. Bowman, F. H., 119. Boys, C. V., 692. Brady, H. B., 639. Braham’s (P.) Microgoniometer, 106. * Brain Function ” of the Tips of Roots, Darwin’s so-called, 529. , Nerve Fibrils of, Preparing, 426. — of Crustacea and Insects, 770. — , Classification of, 503. Bramhall Reflector, Impromptu, 567. Branched Sporogonium of a Moss, 534. Brandt, E., 333,499. —,kK,, : Brautlecht, J., 89. Brefeld’s (O.) Schimmelpilze, 83, Breitenbach, W., 35. Brewer, W. H., 861. Briggs, D. H., 277, 283. Briosi, G., 361. INDEX. Brisinva, 631. British Cladocera, New, from Grasmere Lake, 187. Fresh-water Algze, Cooke’s, 246. Oribatidee, Further Notes on, 1. Brock, J., 485. Brook, G., 866. Brosike, G., 427. Brown, Bismarck, Staining Living Protoplasm with, 278. Browning’s (J.) Portable Microscope, 252. Simple Heliostat, 413. Briicke Lens, 101, 400. Brun, J., 887. Brunet, D., 385. Bryan, G. H., 287. Bryozoa, Avicularia in, Modifieations of, 183. , Cheilostomatous, Development of Genital Products of, 769. : —,, Embryology of, 492. —, New Adriatic, 494. Bubbles given off under Water, Deter- mination of the Activity of Assimila- tion by, 223. , Vacuum, in Canada Balsam, 581. Buchner, H., 89, 657, 832. Buds, Adventitious, on the Lamina of the Frond of Asplenium bulbiferum, 226. Bufelius, G., 703. Bulloch’s (W. H.) Apparatus for Mea- suring Power of Hye-pieces, 678. — Diatom Stage, 554. Newer Congress Stand, 666. Burgess, EH. W., 665. Burnett’s Rotating Live-Box, 410. Biisgen, M., 826. Biitschli, O., 205, 358, 481, 708. Protozoa, 799. Butterfly Scales, Mounting, 277. Bye-Laws, Alteration in, 140, 2389. Cc Cabinet for Slides, 747. Caddis-fly, Marine, 610. Caleareous Skeleton of Asteroides, Development of, 514. Calcium Carbonate, Decomposition of, in the Stem of Dicotyledonous Woods, 527. Callus-plates of Sieve-tubes, 218. Camel, Nematoid Heematozoon from, 509. Camera Lucida, Abbe’s, 261, 593. —,, Cramer’s, 679. —— — ., Curtis’ Drawing Arrange- ment, 262. —— ——,, Drawing on Gelatine with, 262. INDEX. ©amera Lucida, Hoffmann’s, 679. —— ——,, Moore’s, 865. —— ——, Nachet’s Improved, 260, , Oberhauser’s, 679. Cameron, P., 276. Campbell, F. M., 614. Caoutchouc Cement, Miller’s, 579. Caps, Metal, for Glycerine Mounts, 725. Carbolic Acid and Balsam, Mounting Histological Preparations with, 425. Carbonic Oxide, Power of Plants to absorb, 819. Carmine and Anilin Green, Double Staining with, 576. Carmine-solution, Cochineal, 426. Carpenter, P. H., 199. Carriére, J., 510, 604. Carter, H. J., 350, 798. Cartilage, Living, Examination of, 128. Cassiopeia borbonica, Metamorphoses of, 58. Cattaneo, G., 87, 206, 359. Cattle- Disease, a New Fungoid (Aktinomykosis), 236. - —— -distemper, Bacteria of, Experi- mental Production of, 382. Caucasian Milk Ferment, Bacteria of, 383. Caudal Sete, Cercaria with, 192. — Spine of Limulus, Function of, 41. Caudereau, 123. Ceci, A., 832. Celakovsky, L., 648. Cell- and Nuclear-Division in the Formation of the Pollen of Hemero- callis fulva, 809. —, Apical, Energy of Growth of, and of the youngest Segments, 67. Cell-division and Development of the Embryo of Isoétes lacustris, 375. Cell-formation, Free, in the Embryo- sac of Angiosperms, 214. of Plants, Influence of Warmth of the Soil on, 70. Cell, Griffith, 284. Cell-growth, Apical, in Phanerogams, 523, Cell-membrane, Lignified, Indol as a Reagent for, 282. Cell-nuclei of Pinguicula and Utricu- laria, Crystalloids in, 366. Cell-nucleus and Chlorophyll, 69. SNA. Division of, in Spirogyra, in Chara foetida, 79. —— in the Mother-cells of the Pollen of Liliaceze, 366, Cell-structure, 317. — Vegetable, Structure and Division of, 214. 917 Cell-wall in Fungi, Chemical Nature of, 228. 810. Cells, Antipodal, Functions of, 64. —-, Card, Spring Paper-clip for fastening upon Slides, 446. —, Chalk, 718. — Chlorophyllian, Prolongation of Vegetative Activity of, under the Influence of a Parasite, 93. ——, Embryonic, Division of, in the Vertebrata, 478. —., Mother-, of the Pollen of Lilia- ceze, Cell-nucleus in, 366. , Paper, 578. ——, Salivary, of the Larvze of Chiro- nomus, Nucleus of, 185. ~ ——,, Sexual, of Hydroida, 60. ——.,, Spiral, in Crinum and Nepenthes, 3 , Structure and Growth of, , Stinging-, of Ceelenterata, Cha- racters of, 200. —, Vegetable, Oxide on, 68. —— ——, Disengagement of Oxygen by, in the Microspectrum, 661. —, Yellow, of Radiolarians and Ceelenterates, 244. ——, Wax, 578. Cement, Miller’s Caoutchouc, 579. —,, “ Patent Knotting ” as, 745. ——,, Venice Turpentine as, 724. Centering Objects on the Slide, 717. Cephalopoda, Anatomy and Classifica- tion of, 485. ——,, Development of, 328. ——,, Digestion of Amyloids in, 30. ——, Infusoria Parasitic in, 63. ——,, Ink-sae of, 487. ——, North American, 604. , Sense of Colour in, 489. Cephalotus follicularis, Pitchers of, 220 Action of Nitrous Cercaria with Caudal Sete, 192. Certes, A., 43, 279, 280, 425, 576, 804. Cestodes, Anatomy of, 785. ——, Nervous System of, 51. ——,, Studies on, 786. Cheetomium, 376. Chalk Cells, 718. ‘ Challenger’ Ascidians (Culeolus), 182. ——,, Tunicata of, 33. Chamberland, 238, 239. Chara. See Contents, Characez. Characez. See Contents. Charbon, Bacterium of, 541. Chatin, J., 51, 767. Cheeseman, E. L., 436. _ Cheilostomatous Bryozoa, Genital Pro- ducts of, Development of, 769. 918 Chemical Composition of Mosses, 375. of Moulds, 538. — —— of Tubes of Onuphis, 509. — Difference between Dead and Living Protop'asm, 67, 361, 440, 522, 902. (Micro-) Methods for Mineral Analysis, 736. Nature of the Cell-wall in Fungi, 228. Chick, Blastoderm of, Preparing, 570. — _, Early Changes of, 758. ——, Germinal Layers of, 314. Chilton, C., 778. Chinch Bug, Bacterial Parasite of, 830. Chironomus, Salivary Cells of Larve of, Nucleus of the, 185. Chiton, Kidney of, 179. Chloeon diptera, Eye of, 609. Chlorophyll and Hypochlorin, 817. and the Cell-nucleus, 69. —— -corpuscles and Amyloid Deposits of Spongilla and Hydra, 322. —, Function of, 818. ——, History of Assimilation and of the Functions of, 525. — -pigment, Vitality of, 818. Chlorophyllaceous Plants, Occurrence of Aldehydes in, 361. Chlorophyllian Cells, Prolongation of Vegetative Activity of, under the Influence of a Parasite, 93. Cholera, Parasitic Nature of, 384. Cholodkowsky, N., 483. Christo Apostolides, K. N., 199, 789. Chromogenous Schizomycete on Cooked Meat, 655. Chun, C., 200, 204, 633. Ciaccio, G. V., 29, 609. Ciliated Sac and Ganglion in Pyrosoma, Development of, 769. Ciliation of the Hypotrichous Infusoria, 636. Cilio-flagellata, Organization of, 351. Circle-cutter, Bausch and Lomb’s, 285. Circulating Apparatus of Star-fishes, 347. Circulation or Growing Slide, New, 19. Circulatory Apparatus of Regular Echi- noids, 789. Cladocera, New British, 187. Classification and Anatomy of Schi- zeacer, 226. of the Cephalopoda, 485. of Nostoc, 93. — of Sphagnacee, 79, 653. —— of the Brain of Crustacea, 503. — —— Gregarinida, 356. — Nematohelminthes, 340. Claus, C., 58, 515. Clavularia prolifera, 349. Cleaning Diatoms, 428. —— INDEX. Cleaning Gizzards, 435, 436, 437, 438. — used Slides and Covers, 583. Climbing Plants, 531. ri intermedium, Division of, 665. Coal, Cutting Sections of, 577. Coccidia, 643. Cochineal Carmine-Solution, 426. Ceelenterata. See Contents. Coenogonium and the Schwendenerian Theory, 389. Cold, Extreme, Resistance of Seeds to, 66 — or Hot Stage, 21. : Coleoptera, Aquatic, Want of Cutaneous Absorption in, 771. ——,, Striated Muscle of, and its Nerve- endings, 33. Cole’s (A. C.) “Studies in Micro- scopical Science,” 420. Collar Correction of Objectives, 685. —— (Screw) Adjustment, Deby’s, 107. Collecting, &c., Objects. See Contents. Collenchyma, 71, 812. Colour Corrections of Achromatic Ob- jectives, 109. ——, Perception of, by Crustacea, 615. —, Sense of, in Cephalopoda, 489. — Sense in Crustacea, 43. Colouring Living Microscopical Organ- isms, 425, Matter from the Aphis, 39. Colours of Flowers, 821. Comatule, American, 199. Comatulidz, Formule for, 791. Comes, O., 827. Committee on Ruled Plates, 861. —on Standard Gauges for Eye- pieces and Substages, Report of, 595, 700. . Compass-flowers, 373. Completoria complens, a Parasite on the Prothallium of,Ferns, 377. Compressorium, Forrest’s, 266. —, Hardy’s, 553. Compte-globules, Malassez’s Improved, 559. - : Concussion, Influence of, on the De- velopments of the Schizomycetes, 382. Condenser, Abbe’s, 411. ——, Beck’s Achromatic, for Dry and Immersion Objectives, 270. ——, Gundlach’s Immersion, 689. ——, Hollow Glass Sphere as, 112, 273, 274. Conferva, Resting-spores of, 836. Confervacex, Relation of Palmella to, 664. Conidial Apparatus in Hydnum, 80. Coniferous Woods, Fossil Sections of, 13], Willow-tree INDEX. Conn, H. W., 634. Continuous Observations of Minute Animaleula, 731. Contractile Vacuole of Vorticella, 355. Cooke’s (M. C.) British Fresh-water Alge, 246. Copepoda, Fresh-water, Ontogeny of, 776. —_,, New, 617. Copulation, Peculiar Mode of, in Marine Dendroccela, 340. Coral,. Life-history of, 542. Corallina, Structure of, 393. Coral-reef Annelid, 621. Cornea, Nerves in, Distribution and Termination of, 29. Cornevin, 236. Cornu, M., 75, 81, 83, 93, 827. Corpuscles, Tactile, Nerve-endings of, 28. , White, of the Blood, 27. Correction-adjustment for Homogeneous Immersion Objectives, 407, 854. -collar, Measuring Thickness of Cover-glass by, 687. , Collar, of Objectives, 685. Corrections, Colour, of’ Achromatic Ob- jectives, 109. Cortex, Development of, in Chara, 535, Cotton Fibre, Structure of, 119. Council, Report of, 293. Cover-glass, Measuring Thickness of, by Correction-collar, 687. Covers and Slides, Cleaning, 583. Cox, J. D., 102, 111. Cox’s “Simple Section-cutter for Be- ginners,” 126. Crambessa tagi, 59. Cramer, C., 692, 732. , Camera Lucida, 679. Créteur, 262. Crié, L., 222. Crinum and Nepenthes, Spiral Cells in, 813. Cross-fertilization and Distribution of Seeds, 215. of Flowers, and Insects, 653. Crova, A., 677. Crustacea. See Contents. Crustaceous Lichens, Structure of, 389. Cryptogamia. See Contents. — vascularia. See Contents. Eee a New Genus of Mazza, Crystallized Fruit Salt, Eno’s, 435. Crystalloids in the Cell-nuclei of Pin- guicula and Utricularia, 366. of Marine Algze, 390. Crystals, Hemoglobin, Preparing, 427. — , Plant-, 597. ——,, Salicine, Mounting, 283. —, Sphero-, 367, 815. 919 Ctenophora, Imbedding, 278. of the Bay of Naples, 204. Cugini, G., 229. Culeolus (‘Challenger’ Ascidians), 182. Cunningham, K. M., 428. Cupelopagis bucinedax, 625. Curiosities of Microscopical Literature, 697. Curiosity, Microscopic, 288. Curtis’ (L.) Camera Lucida Drawing Arrangement, 262, 263. Cutaneous Absorption, Want of, in Aquatic Coleoptera, 771. Cutter, Circle-, Bausch and Lomb’s, 285. Cutting, 569, 881. and Mounting Sections, 567. — Sections of Coal, 577. —— —— of very Small Objects, 126. Cycades, Reproductive Organs of, 808. Cystoliths in Momordica, 367. Czokor, J., 426. Microscopical D. D., A. R., 745. Dallinger, W. H., 853. Damaschino, 276. Dammar Varnish, 583. Dancer, J. B., 407. © Danielssen, D. C., 791. Daphnia, Heterogeny of, 506. Dareste, C., 378. Dark-field Illumination, 273. Darlingtonia and Sarracenia, Epidermis of the Pitchers of, 72. : Darwin’s so-called ‘ Brain-function ” of the Tips of Roots, 529. Davaine’s Septicemia, Bacteria of, 310. Davidoff, M., 59. Dead and Living Protoplasm, Chemical Difference between, 67, 361, 440, 522, 902. Death and Life in the Animal Organ- ism, 481. Deby’s (J.) Apparatus for chromatic Light, 422. — Screw-collar Adjustment, 107. Decomposition of Calcium carbonate in the Stem of Dicotyledonous Woods, 527. Deep-sea and Pelagic Fauna, 483. Definition of Natural and Artificial Objects, 420. Deighton, F., 314. Delicate Organs, Imbedding, 125. Delogne, C., 706. Demeter, K. v., 219. Dendroccela, Marine, Peculiar Mode of Copulation in, 310. Denomination of Eye-pieces Standard Gauges for same, 103, Mono- and 920 Depth of Vision, 153. Dermaleichide, Structure of, 186. Desiccation of Rotifers, 787. Destruction of Insects by Yeast, 378. of Microscopical Organisms in Potable Water, 585. Detlefsen, E., 74, 529. Detmer, W., 68, 222, 818. _ Vegetable: Physiolog ry, 223. Dentzia, SteHate Hairs of, Preparing, 587. Developmental Process in Birds, Photo- graphs of, 23. Diaphragm for Limiting the Apertures of Objectives, 407. , Gundlach’s Calotte, 859. Iris-, for varying the Aperture of Objectives, 262. , Pennock’s Oblique, 270. Diaphragms, Use of, 441. Diatom Stage, Bulloch’s, 554. Diatomacez, Schmidt’s Atlas of, 249. Diatoms, Cleaning, 428. , Fineness of Striation as a Specific Character of, 247. from the Island of Lewis, 665. — in Peruvian Guano, note on Rey. G. L. Mills’ Paper on, 476. — in Thin Rock Sections, 246. ——, Motion of, 394, 546, 838. — ’ Mounting, Gum- ese for, 142. ——’ of Thames Mud, 9 —— of the Baltic, 837. , Preparation of, 707, 887. Dicyemidee, Observations on, 621, Didymospheria and Microthelia, 230. Difierentiating Motor and Sensory Nerves, 425. Diffusion of Bacteria, 658. Digestion, Intracellular, 602. of Amyloids in Cephalopoda, 30. Digestive Canal of Holothuria, His- tology of, 792. Dimensions of Histological Elements, 762. Dimorpha mutans, 207. Dionza, Leaf of, Electromotive Proper- ties of, 533. Diphtheria, ZMtiology of, 87. Dippel, L., 261, 551, 854. Diptera, Larvee and Pupe of, 772. , — of, Nervous System of, Boos ——., Post-embryonic Development of, 37. Direction of Growth, Influence of External Forces on, 372. Dischidia Rafflesiana, Pitchers of, 651. Disdaplia, 768. Disease, Etiology of Tubercular, 385. —, new Fungoid Cattle- (Aktino- mylxosis), 236. INDEX. | Disease, Salmon, 538. Diseases, Connection of, with Specific Bacilli, 89. of Plants, Frank’s, 75. Dispersion of Seeds and Fruits, Mecha- nical Contrivance for, 66. Dissecting, 880. Dissociation of Gland-Elements, 123. Distemper and Hay, Bacilli of, Con- nection of, 657. ——, Bacteria of, Experimental Pro- duction of, 832. —. , Etiolozy of, 831. Distribution and Cross-fertilization of Seeds, 215. | ——, Geographical, of Rhizopoda, 356. ——., Water-, in Plants, 373. Division and Structure of the Vege- table Cell, 214. | ——, Cell-, and Development of the Embryo of Isoetes lacustris, 375. — of Closterium intermedium, 665. —— of Embryonic Cells in the Ver- tebrata, 478. eee the Cell-nucleus in Spirogyra, Doliolum, Alternation of Generations in, 331 -——, Natural History of, 768. Dowdeswell, G. F., The Bacteria of Davaine’s Septiceemia, 310. Drasche, R., 331. Drawing Apparatus, Hartnack’s, 402. Arrangement, Curtis’ Camera . Lucida, 262. ——, Methods for, 424. — from the Microscope, 40+. — Objects, Apparatus for, 424. —on Gelatine with the Camera Lucida, 262. Drepanidium ranarum, Cell-parasite of Frog’s Blood and Spleen, 519. Dressings, Parasitic Organisms of, 384. Dry and Immersion Objectives, Beck’s Achromatic Condenser for, 270. : -— Mounting, Wax and Guttapercha in, 285. — Mounts, Moisture in, 583. —— Preparations, Method for, 705. Duncan, P. M., 443. —— —,, The President’s Address, 145, Dupetit, M., 834. Du Plessis, G., 58. Durable Preparations of Microscopical Organisms, 120. Duramen, Formation of, Properties and Mode of, 525. Dyes, Aniline, and Vegetable Tissues, 281. ‘ INDEX. E. Rar-fungi, 83. Ear, Human, Parasites of, 655. Early Development of the Mole, 173. Eau de Javelle for Removing Soft Parts, 889. Eccentric Growth, Causes of, 74. Echinodermata. See Contents. Echinoidea, Hybridization of, 515. ——, Regular, Circulatory Apparatus of, 789. , Spicules found in the Ambu- lacral Tubes of, 297. Kchinoids, Anatomy of, 626. Echinorhyncus, 51. Kehiurida, 47. , Parasites of, 63. Editorial (this Journal), 97, 98, 100, 101, 103, 106, 107, 109, 111, 119, 126, 131, 251, 252, 253, 255, 258, 260, 262, 264, 266, 270, 283, 284, 395, 398, 399, 400, 407, 411, 413, 415, 416, 420, 421, 434, 547, 549, 549, 551, 554, 555, 556, 557, 559, 576, 579, 585, 666, 684, 688, 693, 696, 697, 725, 727, 728, 847, 849, 850, 852, 858, 859, 861, 862. Egeling, G., 240. Ege, Hen’s, Development of Fungi on the Outside and Inside of, 378. in Triton, Genesis of, 479. ——,, Production of Microphytes within, 87. Ehrlich’s Method of Exhibiting the Bacteria of Tuberculosis, 572. Hichler, A. W., 220. ¢ Hisig, H., 44. Elasmobranchs, Paired Fins of, De- velopment of, 23. Eleock, C., 436, 886. Electric Light in Microscopy, 418, 557. — Organs of Gymnotus, 602. Electrical Researches on Plant Forms, 932. Electromotive Properties of the Leaf of Dionzea, 533. Elfving, F., 533, 538, Elsden, J. V., 130. Elytra of Aphroditacean Annelids, 779. Embryo and Embryo-sac, Development of, 643. — and Prothallium of Azolla, 76. — in Lupinus, Development of, 807. of Isoetes lacustris, Cell-division and Development of, 375. -—., Vegetable, Organs not hitherto described in, 361. Embryology and Histology of the Phanerogamia. See Contents. —— —— of the Vertebrata. Contents. Embryograph, His’s, 402. See 921 Embryo-sac, Development of, 805. of Angiosperms, Free- cell Forma- tion in, 214. , Origin of, and Functions of the Antipodal Cells, 64. Embryonic Cells, Division of, in the Vertebrata, 478. —— Membranes of the Salpidee, 182. Embryos of Insects, Preparing, 570. Engell’s Class or Demonstrating Micro- scope, 398. Engelmann, T. W., 260, 380, 656, 663, 725. Microspectral Apparatus, 661. Engineering Work, the Microscope in, 733. Engler, A., 544. Enelish’s (J. L.) Method of Preserving Hymenomycetes and Wild Flowers, 283. Enock, F., 725. Entomostraca, Mounting, 746. , Preparing, 439. Entoniscida, 188. Entozoa confounded with 342. Entz, G., 120, 542, 840. Eozoon Canadense, 360. Epidermal System of Roots, 73. Epidermis of the Pitchers of Sarracenia and Darlingtonia, 72. , Preparation of, 883. Ercolani, G. B., 784. Eriksson, J., 221. Ermengem, E. van, 266, 573, 706. Krrera, L., 824. Etiolation of Plants, Causes of, 822. Etiology of Diphtheria, 87. —— of Distemper, 831. of Malarial Fevers, 235, of Tubercular Disease, 385. Eucopida and Geryonopsida, Develop- ment of, 58. Eudendrium ramosum, Organ in, 203. Eunicid, Parasitic, 190. Euphorbia Lathyris, Latex of, 529. Examining, &c. See Contents. Excrement, Human, Vegetable Organ- isms in, 234. of the Domestic Goat and Goose, Organisms found in, 749. Excretion of Water on the Surface of Nectaries, 223. Excretory Apparatus of Turbellaria, 344. Trichine, Remarkable Experimental Production of the Bac- teria of the Cattle-distemper, 382. Tuberculosis, 385. Eye, Facet-, Sensations of Sight Con- veyed by, 494. of Chloeon diptera, 609. 922 Eye, Unpaired, of Crustacea, 504. Eye-pieces and Substages, Standard Gauges for, Report of Committee on, 595, 700. , Denomination of, and Standard Gauges for same, 103. — , Designation of, 853. —, Measurement of the Power of, 678. — , Steinheil’s Achromatic, 551. Eye-protector, Hall’s, for use with the Monocular Microscope, 678. Eyes of Planarians, 510. — of Rotifers, 512. F. Facet-eye, Sensations of Sight conveyed by, 494. Falkenberg, P., 394. Farlow, W. G., 394. Fasoldt’s Test-plate, 415. Fat-globules and Air-bubbles, Appear- ances presented by, in White and Monochromatic Light, 742. Fauna, Anthozoan, of Naples, Prodrome of O7- ——, Pelagic and Deep-sea, 483. , of Fresh-water Lakes, 765. Fecundation, Maturation, and Segmen- tation of Limax campestris, 178. Fehlner, C., 534. Fell, G. E., 417, 425. Female Receptacle of the Junger- manniex Geocalycee, 227. Ferment, Caucasian Milk-, Bacteria of, 383. — , Diastatic, of Bacteria, $29. Fermentation of Maize-starch, 833. of Nitrates, 834. , Prevention of, by Vegetable Acids, 833. ; Ferments, Connection of Bacteria with, 541. Ferns, Prothallium of, Completoria complens, a Parasite on, 377. , Relation of Nutrition to the Distribution of the Sexual Organs on, 374. Fertilization, Cross-, and Distribution of Seeds, 215. —— of Apocynacez, 215. of Salvia splendens, 363. Feyer, Intermittent-, Bacteria of, 830. Fevers, Malarial, Etiology of, 235. Fewkes, J. W., 192, 634. Fibre, Cotton, Structure of, 119. Fibrine, Formation of, 479. Fibroyascular Bundles of Monoco- tyledons, 370. Filicinex, Leaf-stalk of, Stomata in, 226. Filtering Wash-hottle, 746. INDEX. Finder, Flesch’s, 409. Fine Adjustment, Bausch and Lomb’s 683. —— —, Substage-, 554. Fineness of Striation as a Specific Character of Diatoms, 247. Fingers, Mechanical, Kain’s and Sidle’s, 721. Fins, Paired, of Elasmobranchs, De- velopment of, 23. Fischer, A., 828. Fission of Phialidium variabile, 59. Flagellata, 62, 518. Fleming, J., 436, 586. Flemming, W., 317, 715, 883. Flesch, M., 423, 699, 726, 883. Finder, 409. Flight of Insects, 184. ——,, Organs of, in Hemiptera, 772. Floscularia, New, 787. Flour, Wheat-, Microscopical Examina- tion of, 584. Flowers, Colours of, 821. ——., Cross-fertilization of, 653. ——, Preserving, 283, 428. Fluids, Apparatus for Examining, 700. — for Homogeneous Immersion, 264, 551. Fluke, Liver-, Life History of, 342. Foettinger, A., 63, 346. Food, Influence of, on Sex, 30. “ Foot” of Terrestrial Gastropoda, 489. Foraminifera, Fossil, Preparing, 886. , Porcellanous, New Type of, 639. , Preparing, 436. Forbes, S. A., 617, 625, 830. Forces, External, Infiuence of, on the Direction of Growth, 372. Forel, F. A., 765. Formic Acid in Plants, 819. Formule for Comatulide, 791. Forrest’s (H. A.) Compressorium, 266. Fossil Coniferous Woods, Sections of, 131. — Foraminifera, Preparing, 886. Organisms in Meteorites, 176. —— Plant, Stomata in, 813. — Siphonee, 394. Fowl-cholera, New Method of Vacci- nation for, 239. Fraipont, J., 345. Francotte, P., 344. Frank, A. B., 528. —, B., 75. Frédéricq, L., 125, 763, 771. French Crustacea, New and rare, 186. Fric, J. A., 776. Fritsch, G., 602, 673. Frog’s Blood and Spleen, Cell-parasite of (Drepanidium ranarum), 519 Frond of Asplenium bulbiferum, Ad- ventitious Buds on Lamina of, 226. INDEX. Front Lenses of Homogeneous-immer- sion Objectives, Scratching, 264. Fructification, Male, of Polytrichum, 823. Fruit Salt, Eno’s Crystallized, 435. Fruits and Seeds, Dispersion of, Me- chanical Contrivance for, 66. Fuchs, T., 483. Fucus amylaceus, Composition of, 834. Fuess’s large Mineralogical and Petro- graphical Microscope, 845, Fungi. See Contents. Furtado, F. d’A., 330. G. Gabriel, B., 356. Galls, Formation of, 500. , Origin of, 823. Galvanic Current,Influence of, on Grow- ing Roots, 533. Ganglion and Ciliated Sac in Pyrosoma, Development of, 769. Gaseous Matter, Examination of, Shur- ley’s Improved Slide for, 551. Gases, Action of Various, on Plants, 818. Gasteropods, Curious Secretion in, 766. —, Terrestrial, “ Foot ” of, 489. Gauges, Standard, for Eye-pieces, and Denomination of same, 103. ——, for Eye-pieces and Sub- stages, Report of Committee on, 595, 700. Gaule, J., 428, 520. Gaunersdorfer, J., 525. Gayon, 834. Gazagnaire, J., 607. Geddes, P., 204, 244. Gelatine, Drawing on, with the Camera Lucida, 262. Generations, Alternation of, in Dolio- lum, 331. —— —— in the Hypodermie, 827. in Uredinesx, 80. Genesis of the Egg in Triton, 479. Genetic Relationship and Morphology of Pathogenous Bacteria, 541. Genital Gland and Segmental Organs of some Sipunculida, 47. — Passages of Asterias, 348. Products of Cheilostomatous Bryozoa, Development of, 769. Geocalycex (Jungermanniesx), Female Receptacle of, 227. Geographical Distribution of Rhizo- poda, 356. Gérard, R., 74. Gerlach, L., 124. Germinal Layers and Early Develop- ment of the Mole, 173. — — of the Chick, 314. 923 Germs of Artemia salina, 43. — of Malaria, 832. Geryonopsida and Eucopida, Develop- ment of, 58. Gessard, C., 384. Giard, A., 194, 778. Gibbes, H., 895. Gibier, 541. Giesbrecht, W., 506, 888. Girod, P., 487. Gizzards, Mounting and Cleaning, 435, 436, 437, 438. of Insects, Mounting, 704. Gland Elements, Dissociation of, 123. , Genital, and Segmental Organs of some Sipunculida, 47. Glands, Phyllomie Nectar-, in Poplars, 219, —, Secretory, Structure of, 814. Glass Sphere, Hollow, as a Condenser, 112, 273, 274. Globe Lens, Gundlach’s, 852. Glycerine and Gum for Imbedding, 890. Glycerine-jelly Mounts, 436, 437, 438. , Mounting in, 127. Mounts, Metal Caps for, 725. Glycogen of Plants, 824. Goat, Domestic, and Goose, Organisms found in the Excrement of, 749. Gobi, C., 213. Godlewski, E., 651. Goebel, K., 224, 535, 823. Golgi, C., 123, 276. Goltzsch’s Binocular Microscope, 95. Goose and Domestic Goat, Organisms found in the Excrement of, 749. Goppert, 131. Gorgoniadx, Studies on, 796. Graeffe, E., 350. Graff, L., 491. Grains, Starch-, Structure of, 368. T.S. Up de, 416. Grasmere Lake, New British Clado- cera from, 187. Grassi, B., 357. Greef, R., 47, 59, 63, 780. Green, J. H., 436. —, Anilin, and Carmine, Double Staining with, 576. » lodine- and Methyl-, 883. » for Human and Animal Tissues, 716. —-— Light for Microscopical Observa- tions, 725. Gregarines, New, 521. Gregarinida, Classification of, 356. Griesbach, H., 605, 716. Griffith, C. H., 578. Griffith’s (E. H.), Cell, 284. —— Parabolic Reflector, 266. —— Portable Microscope, 395. 924 INDEX. Grimshaw, R., 733. Grinding Section-Knives, 899. Grobben, C., 331. Groups of Plants, Development of Tissue as a Characteristic of, 524. Groves, J. W., 430. , A further Improvement in the Groves- Williams Hther Freezing Microtome, 755. Growing or Circulation Slide, New, 19. Growth, Apical Cell-, in Phanerogams, 523. , Direction of, Influence of Hx- ternal Forces on, 372. , Eccentric, Causes of, 74. , Energy of, of the Apical Cell and of the youngest Segments, 67. of Penicillium, Influence of Light on, 87. of Starch-grains by Intussuscep- tion, 70. Gruber, A., 207, 208, 800. Grunow, A., 246, 835. Guano, Peruvian, Diatoms in, Note on Rey..G. L. Mills’ Paper on, 476. Guignard, L., 64, 65, 644, 805, 807. Guillemare’s School Microscope, 669. Gum and Glycerine for Imbeiding, 890. —— Juniper for Mounting Diatoms, 142, Gunda segmentata, Structure of, 197. Gundlach, E., 691. Calotte Diaphragm, 859. College Microscope, 670. — Globe Lens, 852. z-Inch Objective, 263. Immersion Condenser, 689. Substage Refractor, 692, 860. Guttapercha and Wax in Dry Mount- ing, 285. Gymnotus, Electric Organs of, 602. H. Haberkorn, T., 541. Haberlandt, G., 368, 523, 816. Habits of Scorpions, 612. Heematococeus, Disengagement of Oxygen by, 663. Hematometer, Hayem and Nachet’s Modified, 413. Heematozoon, Nematoid, from a Camel, 509. Hemoglobin Crystals, Preparing, 427. Hail and Rainwater-ice, Micro-organ- isms from, 450. Hailstones, Microscopical Characters of, 741. Hairs of Plants, Mounting, 748. , sense-, of the Hydrachnida, 775. Sr Stellate, of Deutzia, preparing, 87. Hall’s (lL. B.) Eye-protector for use with the Monocular Microscope, 678. Haller, G., 186, 775. Hamann, On, 792, 793. Hamingia elacialis, 50. ‘Hampden ” Portable Simple Micro- scope, 208. Hanaman, C. H., 746. Handwriting, Microscopical Examina- tion of, 727. Hansen, AG. 46, 525. ; E. Cc, 234. Hardening, 567. Fluid, Perenyi’s, 709. Hardy’s (J. D.) Compressorium, 553. Harkness, W., 107, 109. Harris, W. Th 577. Hart, Mrs. E., 479. . Ee 378. Harting’s (P.) Binocular Microscope, 253. Hartnack’s (H.) Demonstration Micro- scope, 97. Drawing Apparatus, 402. Hartog, M. M., 439, 504. Haswell, W. A., 779, 799. Hatschek, B., 175. Hay and Distemper, Bacilli of, Con- nection of, 657. Haycraft, J. B., 319. Hayduck, M., 540. Hayem and Nachet’s Modified Heema- tometer, 413. Heape, W., 173. Heat, Production of, by Intramolecular Respiration, 221. Heating Apparatus, Julien’s Stage, 266. Heinricher, H., 226. Heliostat, Browning’ s Simple, 413. Heliozoa, Recent Researches on, 205. Helix pomatia, Mucin of, 490. Hemerocallis fulva, Pollen of, Cell- and Nuclear Division in the Formation of, 809. Hemiptera, Organs of Flight in, 772. Hemispherical Lens, Prisms as Illu- minators versus, 556. Hennéguy, L. F., 278, 478. Hensoldt’s Simplified Reading Micro- scope for horizontal and vertical cir- cles, 548. Hen’s Eggs, Development of Fungi on the Outside and Inside of, 378. Hepaticee and Mosses, Mounting, 706. Herbarium, Herpel’s Method of pre- paring Fungi for, 122. Herdmann, W.A., 33, 182. Herpell, G., 122. Herrick, C. ‘lie 506. Hertwig, R., 275, 276, 278, 795. | Hesse, M., 186. INDEX. Hesse, R., 654. Heteractinism in Echinodermata, 788. Heterogeny of Daphnia, 506. Heurck, H. van, 264, 265, 418, 557. Hildebrand, F., 215, 524. Hineks, T., 183. Hirudinea and Ceelenterata, Relation- ships of the Platyhelminthes with, 197. His’s Embryograph, 402. Histological Elements, Dimensions of, 762. Histology and Embryology of the Phanerogamia. See Contents. -—— of the Vertebrata. Contents. and Microscopy, Section of, at the American Association, 119. Hitcheock, R., 409, 415, 416, 861. Hoek, P. P: C., 335. Hofmann’s Camera Lucida, 679. Hogg on the Microscope, 862. Hohnel, F. BR. v., 216, 814. Holdsworth, 8. R., 127. Holmes, E., 423, 731. Holothuria, Digestive Canal of, Histo- logy of, 792. Holothurians, Anatomy of, 512, 632. Holothuroidea of the Norwegian North Sea Expedition, 791. Homogeneous-immersion, of, 265. See Advantage and Water-Immersion Ob- jectives, 685. , Fluids for, 264, 551. —— —— Objectives, Correction-adjust- ment for, 407, 854. ——, Powell’s =., 565. , Seratching the Front Lenses of, 264. Principle, 152. Homology of the Ovule, 648, 808. Hoppe-Seyler, F., 376. Horst, R., 50, 330. Hot or Cold Siage, 21. Hot-water Stage, Schklarewski’s, 411. Hubrecht, A. A. W., 31, 180, 331. Hudson, C, T., 787. Huet, 337. Human Excrements, Vegetable Organ- isms in, 234. Hunt, J. H., 710. Huxley, T. H., 538. Hyatt, J. D., 516. Hybridization in Fresh-water Sponges, 3. of Echinoidea, 513. Hydnum, Conidial Apparatus in, 80. Hydra, 794. and Spongilla, Chlorophyll-cor- puscles and Amyloid Deposits of, 322. 925 Hydrachnida, Sense-hairs of, 775. Hydroid Polyps, Nervous System of, 202. , Organization of, 793. Hydroida, Sexual Cells of, 60. Hydrotropism of Roots, 74. Hydrozoa, Spermatozoa of, 60. Hydrurus, 664. Hymenogastree, a New Genus of (Leucogaster), 654. Hymenomycetes and Wild Flowers, English’s Method of Preserving, 283. Hyphomycetes, a (Beltrania), 538. Hypochlorin, 528. and Chlorophyll, 817. Hypodermiz, Alternation of Genera- tions in, $27. New Genus of I Ice, Rainwater-, and Hail, Micro- organisms from, 450. Illumination, Dark-field, 273. , Symmetrical, 691. Illuminator, Immersion, Bausch and Lomb, 412, 688. , Vertical, for examining Histo- logical Elements, 266. i , Hitchcock’s Modified Form of, 409. Iluminators, Prisms versus Hemisphe- rical Lens as, 556. Image, Apparatus for projecting, to any required Distance with Variable Amplification, 677. Images, Miniatured, 693. Imbedding, 568, 880. — Ctenophora, 278. — Delicate Organs, 125. ——, Gaule’s Method of, 428. — , Gum and Glycerine for, 890. —.-, Paraffin-, Modification of, 708. Tissues in semi-pulped, unglazed printing Paper, Simple plan of, 474, Immersion and Dry Objectives, Beck’s Achromatic Condenser for, 270. Condenser, Gundlach’s, 689. , Homogeneous. See Homogene- ous Immersion. Illuminator, Bausch and Lomb’s, 412, 688. — Objectives, Homogeneous- and Water-, 685. Immunity from Anthrax, Duration of, 239. Impurities of Drinking Water caused by Vegetable Growth, 394. Indices, High Refractive, Mounting in Media of, 156. 926 Indol as a Reagent for Lignified Cell- membrane, 282. pectin by Symptomatic Anthrax, 236. Infusoria and Amoebee, Preserving, 574. and other Microscopical Organ- isms, Preservation of, 279. —, Hypotrichous Ciliation of, 636. ——, Kent’s Manual of, 518. ——., Living, Staining the Nucleus of, 576. —— —,, Sub-class of (Pulsatoria),204. ——, Nucleus of, Staining, 280. —— Parasitic in Cephalopods, 63. ——, Preserving, 706. Infusorian, New Ciliate, 799. —— with Spicular Skeleton, 355. Ingpen, J. E., 441, 746. Injecting, 87 8. — Material, Wywodzen’s, 717. Injection-mass, 125. —, Cold, 275. , Teichmann’s, 716. Injection of Invertebrate Animals, 274. Injections, Transparent, 438. Ink-sac of Cephalopoda, 487. Innervation of the Mantle of Lamelli- branchs, 767. Insecta. See Contents. Insectivorous Plants, 531. Insecticolous Acari, 774. Insects. See Contents—Insecta. Instruments, Accessories, &c. See Contents. Intracellular Digestion, 602. Intussusception, Growth of Starch- grains by, 70. Invertebrata. See Contents. Iodine-green, 716, 883. Iris-Diaphragm for varying the Aper- ture of Objectives, 262. Iscetes lacustris, Embryo of, Cell-divi- sion and Development of, 375» , Sporangia and Spores of, Deve- lopment of, 78. Isopoda, Segmental Organs in, 337. Isthmia nervosa, Areolations of, 129. Iwakawa, T., 479. J. Jako, J., 372. Janczewski, H., 370. Jatta, A., 240. Jickeli, C. F., 202, 794. Jobert, 39. Johne, 236. Johnson, G. J., 746. Johow, F., 79. Joliet, L., 53, 615, 769, 890. Jones, T. R., 423, 564, 746, Joseph, G., 274. INDEX. Jourdain, S., 348. ; Jourdan, E., 512, 632, 792. Journal of the Postal Microscopical Society, 421. Jublin-Dannfelt H., 837. Julien’s Stage Heating Apparatus, 266. Julin, C., 511, 624. Jungermannies Geocalyces, Kemale Receptacle of, 227. Just, L., 819. K. Kain, C. H., 424, 726. —— and Sidle’s Mechanical Fingers, 721. Kallen, F., 363. Katsch’s Large Microtome, 126. Keegan, P. Q., 746. Keller, C., 489. Kent, W. S., 518, 636. Kerbert, C., 782. Kern, E., 383. = Kidney of Chiton, 179. Kienitz-Gerloff, F., 375. Kiesling, F., 786. Killing and Preserving Insects, 748. of Protoplasm by Various Re- agents, 522. King, Prof., 360. Kitton, F., 112, 142, 718, 864, 888. , Note on Rev. G. L. Mills’ Paper on Diatoms in Peruvian Guano, 476. Klebs, G., 601, 764, 804. Klein, J., 366, 390, 544, 840. Kleinenberg, N., 44. Knife, Marsh’s Section-, 712. —,, Thanhoffer’s Irrigation-, 713. Knives, Section-, Grinding, 899. Kny, L., 370, 372. Koch, G. v., 349, 514, 795, 796. 1B, 385, 831. Koehler, R., 513, 626, 627, 789. Koller, C., 570. Koren, a 791. Korschelt, H., 574. Kossmann, R., 188. Kowalevsky, A., 180, 797. Krabbe, G., 388. Kramer, P., 614. Krasan, F., 90. Kratschmar, 361. Kraus, G., 373, 815, 818. Krause, W., 28, 762. Krukenberg, C. F. W., 327. Kiihn, J., 391. Kinekel, A. J., 532. —, J., 38, 131, 607. Kunstler, 62, 518, 803. Kunz, 437. Kupffer, C., 23. INDEX. L. Labelling Slides, 287. Lacaze-Duthiers’ (H.), Microscope with Rotating Foot, 97. Lake, Grasmere, New British Cladocera from, 187. oe ’Fresh- water, Pelagic Fauna of, Lalewski, A., 366. Lamellibranchs, Mantle of, Innervation of, 767. Lamp, New Mechanical, 866. —, Ranvier’s Microscope, 112. Landsberg, B., 575. Landwehr, H. A., 490. Lanessan’s (J. L. de) Protozoa, 517. Lang, A., 51, 194, 197, 340. Lanefeldt, 585. Lankester, E. R., 40, 187, 322, 519, 612, 7 74. Larve and Pupz of Diptera, 772. of Chironomus, Nucleus of the Salivary Cells of, 185. of Diptera, Nervous System of, 333. Latex of Euphorbia Lathyris, 529. Laticiferous Tubes, Compound Proto- plasm of, 805. —— Vessels, 73. Laveran, A., 659. Leaf of Dionza, Electromotive Pro- perties of, 533. — -stalk’ of Filicinees, Stomata in, 226. Leaves, Examination of, 590. Lecky, R. J., 337. Lectures, Public, in Microscopy, 585. Leech, Muscular Tissue of, 621. , Voluntary Muscles of, Termina- tion of Nerves in, 46. Leguminose, Embryogeny of, 644. Leitgeb, H., 227, 377. Lendenfeld, fife v., 184. Lenses, N umber of, required in Achro- matic Objectives, 107. Lenticels of the Marattiacez, 225. Lepidoptera, Structure of the Proboscis of, 35. Lepidosteus, Development of, 316. Leuckart, R., 342. Leucogaster, A New Genus of Hymeno- gastreze, 654. Lewis, T. R., 509. , Diatoms from the Island of, 665. Lichenes. See Contents. Lichtenstein, J., 83. Lieberkuehnia, Nuclei of, 802. Life and Death in the Animal Organ- ism, 481. Light, Action of, on Fungi, 228. ——, on Vegetation, 220. 927 Light and Air, Influence of, on the Anatomical Structure of Plants, 651. —,, Electric, in Microscopy, 418, 557. ——, Extraneous, Excluding, from the Microscope, 260. —,, Green, 725. , Influence of, on the Growth of Penicillium, 87. —, of, on the Thallus of Mar- chantia, 534. —— Modifiers, 565, 699. , Monochromatic, Deby’s Apparatus for, 422. , New Bacterium Sensitive to, 656. Lignified Cell-membrane, Indol as a reagent for, 282. Ligula and Schistocephalus, 786. Liliacese, Pollen of, Cell-nucleus in the Mother-cells of, 366. Limax campestris, Maturation, Fecun- dation, and Segmentation of, 178. Limbach, J., 355. Limbs, Adaptations of, in Atyoida Potimirim, 42. Lime, Oxalate of, in Plants, 653. salts, Function of, 819. Limpricht, G., 79, 653. Limulus, a Crustacean, 337. —,an Arachnid, 40. ——, Function of the Caudal ne of, 41. Line and Pattern Mounting, 718. Lines and Annuli, Black, of Spherules and Threads, 696. Lisle, T., 437. Listing, J. B., 672 Literature, Microscopical, of, 697. Live-Box, Burnet’s Rotating, 410. Objects, Method of Keeping, 438. Liver-Fluke, Life-History of, 342. of Spiders, 39. Liversidge, A., 500. Living and Dead Protoplasm, Chemical Difference between, 67, 361, 440, 522, 902. —— Cartilage, Examination of, 128. —, Keeping Objects, for many months, 438. Microscopical Organisms, Colour- ing, 425. Protoplasm, Staining with Bis- marck Brown, 278. Loew, O., 67, 361, 440, 522, 902. Loewenberg, 655. Lophopus crystallinus, Statoblasts of, = : Test for High-power Objectives, 129. peti Reproductive Organs of, 363. Lord, C. L., 577. Lossner’s Tele-microscope, 547. Curiosities 928 Lovett, E., 565. Lowe, L., 425. Lowest Organisms, Origin of, 90. Ludwig, F., 215. —_—, H., 55, 628. Lupinus, Embryo in, Development of, 807. Lymph of Invertebrates, 327. M. M., C. J., 898. Macfarlane, J. M., 214, 281, Macleod, J., 610. Maddox, R.L.,On some Micro-organisms from Rainwater-Ice, and Hail, 450. — On some Organisms found in the Excrement of the Domestic Goat and the Goose, 749. Madrepores, Skeleton of, 795. Magdala-red, Staining with, 885. Maggi, L., 205, 250, 354, 359. Magnified Objects, Apparent Size of, 861. Magnifying Powers, Table of, 105. Maize-starch, Fermentation of, 833. Malaria, Germs of, 832. , Parasite of, 659. ——, Parasitic Character of Cases of, 659. Malarial Fevers, Etiology of, 235. Malassez, L., 276. , Improved Compte-globules, 559. Malleable Metals, Microscopical Struc- ture of, 130. * Mal nero” of the Vine, 229, 827. Maly, R., 766. Mammalia, Spermatogenesis in, 757. Man, Psorospermie in, 397. Mangin, L., 813. Mantle of Lamellibranchs, Innervation of, 767. Marattiacese, Lenticels of, 225. Marcano, V., 833. Marchantia, Thallus of, Influence of Light on, 534. Marcken, M., 833. Marginella and the Pseudomarginel- lida, 604. Marion, A. F., 180, 797. Mark, B. L., 178. Marsh, 8., 717. —, Section Knife, 712. Marshall, W., 798. Marten’s Ball-jointed Microscope, 672. Matthews, J., 428. Mattirolo, O., 542, 825. Maturation, Fecundation, and Seg- mentation of Limax campestris, 178. Mau, W., 818. INDEX. | Mauler's Blue Glass Slides, 142. Maupas, E., 636, 706, 802. Mayer, P., 866. Mazza, a New Genus of Cryptophycex, 835. M‘Cook, H. C., 333, 613. M‘Lachlan, R., 610. | McMaurrich, J. P., 492. Measurement, Micrometrical, hy means of Optical Images, 559. of the Power of Eye-pieces, 678. ' Measuring Thickness of Cover-glass by Correction Collar, 687. Meat, Cooked, Chromogenous Schizo- mycete on, 655. Mechanical Fingers, Kain’s and Sidle’s, 721. Mechanics and Structure of Stomata, 216. Mediterranean Crustacea, 615. Meéegnin, P., 51, 342. Melicerta, Development of the Ovum of, 53 Membranes, Embryonic, of the Salpidee, Mer, EH., 75, 78, 530, 822. Mercer, A. C., 271. Mercury, Biniodide of, and Iodide of Potassium, Mounting Objects in a Solution of, and in Phosphorus, 163. Mereschkowsky, C., 48, 178, 615. Metallic Oxides, Absorption of by Plants, 526. Metallurgy, the Microscope in, 735. Metals, Malleable, Microscopical Struc- ture of, 130. Metamorphoses of Cassiopeia Borbonica, 58. Metastasis, 221. Metazoa, Development of some, 763. Meteorites, Fossil Organisms in, 176. Methyl-green, 883. Metschnikoff, E., 201, 602, 763. Meunier-Chalmas, 394. Meyer, A., 368. Miall, L. C., 330. Mica-schist, Sections of, 578. Michael, A. D., 426. , Further Notes on British Oriba- tidee, 1. . Micro-chemical Methods for Mineral Analysis, 736. Micrococci, Vaccinal, 661. Microgoniometer, Braham’s, 106. Micrometers, Rogers’, 117. Micrometrical Measurement by means -of Optical Images, 559. Micrometry, Standard for, 114. Microphotographic Apparatus, Stein’s small, 113. Microphytes within the Egg, Produc- tion of, 87. INDEX. Microscope, Bausch and Lomb Optical Co.’s Excelsior Pocket and Dissect- ing, 401. —_— —_ —_ ——_ — _ Handy Dis- secting, 400. — —_ —— — — Professional, 666 ——, ‘Beck’s Histological Dissecting, 852. —,, —— Lithological, 847. ——,, Browning’s Portable, 252. — , Bulloch’s Newer Congress Stand, 666. — , Engell’s Class or Demonstrating, 398 ——,, Fuess’s Large Mineralogical and Petrographical, 845. ——, Goltzsch’s Binocular, 95. ——,, Griffith’s Portable, 395. ——, Guillemare’s School, 669. ——, Gundlach’s College, 670. ——, “Hampden” Portable Simple, 258. ——, Harting’s Binocular, 253. ——,, Hartnack’s Demonstration, 97. ——, Hensoldt’s Simplified Reading, for Horizontal and Vertical Circles, 548. — in Engineering Work, 733. —— in Metallurgy, 735. —, “Jumbo,” 850. —, Lacaze-Duthiers’, with Rotating Foot, 97. , Lossner’s Tele-, 547. ——, Marten’s Ball-jointed, 672. —,, “Midget,” 852. , Nachet’s Portable, 98. ——, Parkes’ Class, 395. —, —— “Drawing Room,” 100. ——, Pelletan’s ‘‘ Continental,” 700. ——,, Piffard’s Skin, 100. ——, Prazmowski’s Micrometer, 547. —, Pringsheim’s Photo-chemical, 395. —, Robin’s Dissecting, 101. ——,, Rosenbusch’s Petrographical, 842. —,, Schieck’s, with Large Stage, 673. ——, Schrauer’s, 700. ——,, Schroder’s Projection-, 673. —, Seibert and Krafft’s, Improve- ments in, 423. ——,, Sidle’s “ Acme” Class, 251. —, Swift’s Petrological, 849. —, —— Tank, 549. “Ee Teasdale’s Field Naturalist’s, —, Waechter’s (or Engell’s) Class or Demonstrating, 398. ——, —— Travelling Dissecting, 677. ——, Wasserlein’s Saccharometer, 399. ——, Wenham’s Universal Inclining and Rotating, 255, 400. Microscopes, Binocular, 416. Ser. 2.—Vot. II. 929 Microscopes, Polarizing, 672. Microscope-tube, Nachet’s bodied, 255. Microscopy. See Contents. “Microscopy and Histology,’ Section of, at the American Association, 119. Microspectral Apparatus, Engelmann’s, 661. Double- Microspectrum, disengagement of Oxy- gen by Vegetable Cells in, 661. Micro-stereoseopic Vision, 154. Microthelia and Didymospheria, 230. Microtome, Boecker’s, 893. , Cox’s Simple, for Beginners, 126. ——, Groves-Williams Ether Freezing, Further Improvements in, 755. ——,, Katsch’s Large, 126. —,, Roy’s, 892. ——, Satterthwaite and Hunt’s Freez- ing, 710. ——,, Swift and Son’s improved, 432. ——, Williams’ Freezing, adapted for use with Ether, 430. ——, Windler’s, 711. Miles, J. L. W., 273. Milk Ferment, Caucasian, Bacteria of, 383. Miller’s Caoutchouc Cement, 579. Mills, H., 840. Milne-Edwards, H., 238, 508. Mimosez, Polyembryony in, 65. Mineral Analysis, Micro-Chemical Methods for, 736. Minerals and Organisms, Distinctions between, 320. ——,, Rough, Examining, 437. Miniatured Images, 693. Minks’s Licheno-mycological Symbols, 542. Miquel, P., 88. Mirrors, Concave, Lenses v., 692. Mites, Segmentation in, 614. Mocquard, F., 505. Model Stand, 102. Mohr, R. G., 425. Moist Objects, Mounting, in Balsam, 582. Moisture in Dry Mounts, 583. Mole, Germinal Layers and Early Development of, 173. Moleyre, L., 772. Molisch, H., 527. Moliusca. See Contents. Molluscoida. See Contents. Momordica, Crystoliths in, 367. Monas Okenii Ehr. = Bacterium ru- bescens Lank., 640. Moniez, R., 786. Monnier, D., 320. , G. Le, 229, Silvered Convex 3 R 930 Monochromatic and White Light, Ap- pearances presented by Air-bubbles and Fat-globules in, 742. Light, Deby’s Apparatus for, 2 422. Monocotyledons, Fibrovascular Bundles of, 370. Moore, A. Y., 685, 714. Camera Lucida, 865. Mori, A., 526. Morphology and Genetic Relationship of Pathogenous Bacteria, 541. — of Protozoa, 359. of the Amphineura, 331. Morris, 579. Morrison, 424. Mosses. See Contents—Muscinez. Mother-cells of the Pollen of Liliacezx, Cell-nucleus in, 366. Motion of Diatoms, 394, 546, 838. Moulds, Chemical Composition of, 538. Mounting, 569, 879. See also Contents. and Cleaning Gizzards, 436, 437, 438. —— and Cutting Microscopical Sec- tions, 567. and Preparing Soft Tissues, 123. —— Butterfly-Scales, 277. — Diatoms, Gum Juniper for, 142. ——, Dry, Wax and Guttapercha in, 2805. —— Entomositraca, 746. Fungi, 748. — Gizzards of Insects, 704. — Histological Preparations with Carbolic Acid and Balsam, 425. in Balsam, 126. —— in Glycerine, 127. —— in Phosphorus, 579. —— in Pure Balsam, 717. ——, Line and Pattern, 718. — -Media of High Refractive In- dices, 156. —— Moist Objects in Balsam, 582. — Molluscan Palates, 746. — Mosses and Hepaticze, 706. Objects in Phosphorus and in a Solution of Biniodide of Mercury and Iodide of Potassium, 163. —— Plant-hairs, 748. — Salicine Crystals, 283. —— Scales of Insects in Phosphorus, 134. — Sections in Series, 888. — Starches, 435. —— the “Saw ” of the Tenthredinide, 276. ——, Unpressed, 884. Volvox, 436, 585, 586, 746. Mounts, Dry, Moisture in, 583. , Glycerine-jelly, 437, 438. Movement, Amoeboid, Theory of, 319. INDEX. Bean and Structure of Protoplasm, —— of Pollen-tubes, Cause of, 650. — of Water in Plants, Causes of, 373. —,, Power of, in Plants, 531. —., Ulmer’s Silk Thread, 406. Mucin of Helix pomatia, 490. Mueorini, 661. Mud, Thames, Diatoms of, 94. Miiller,-C., 79. + (Oh dJ-., 319)- —, F., 42. ——, Hi, 771. —., J., 389. — -Thurgau, H., 821. Murray, G., 245. Muscines. See Contents. Muscle, Striated, of Coleoptera and its Nervye-endings, 33. , of Insects, Terminations of the Motor Nerves in, 34. — , Voluntary, of the Leech, Termi- nation of Nerves in, 46. Muscular Tissue of the Leech, 621. Musset, C., 653. Myo-Spectroscope, Ranvier’s, 113. Myriapoda. See Contents. Mytilide and WNaiades, System of, 605. Myxosporidia, 358. Vascular . N. Nachet’s (A.) Double-bodied Micro- scope-tube, 255. —— —— Improved Camera Lucida, 260. —— —— Portable Microscope, 98. —— and Hayem’s Modified Hzmato- -mneter, 413. Naegeli, C., 70, 382. Naiades and Mpytilide, System of, 605. Naples, Anthozoan Fauna of, Prodrome of, 57. —, Otenophora of the Bay of, 204. ——, Siphonophora of the Bay of, 204. — , Zoological Station at, Methods of Microscopical Research in use in, 866. Nassau Adjustable Spiral Spring-Clip, 725. Nathorst, A. G., 324. Natural and Artificial Objects, Defini- tion of, 420. Nectar Glands, Phyllomic, in Poplars, 219. Nectaries, Surface of, Excretion of Water on, 223. Nelson, E. M., 554, 565, 584. ——, Adapter for Rapidly Changing Objectives, 858. Vascular INDEX. Nematohelminthes, Classification of, 340. Nematoid Hsematozoon from a Camel, 509. Neomenia, Morphology of, 180. Nepenthes and Crinum, Spiral Cells in, 813. Nerve-endings of Tactile Corpuscles, —— ——, Striated Muscle of Coleop- tera and its, 33. Nerve-fibres, Large, in the Spinal Cord of the Pike, 295. —— — of Unionide, Differentiation of Protoplasm in, 767. Nerve-fibrils of the Brain, Preparing, 426. Nerves in the Cornea, Distribution and Termination of, 29. —— in the Voluntary Muscles of the Leech, Termination of, 46. —, Motor and Sensory, tiating, 425. ——, Motor, in the Striated Muscles of Insects, Terminations of, 34. Nervous System, Central, of Annelids, Development of, 619. —_ — — — , Origin of, 44. —— — of Cestoda, 51. — — of Hydroid Polyps, 202. —— —— of Larve of Diptera, 333. —— —— of Mollusca, 603. —— —— of Ophiuroidea, 199, —— — of Platyhelminthes, 194. —— —— of Strepsiptera, 499. Nest-forms of the Furrow Spider, 613. New Zealand, Blind Subterranean Crustacea in, 778. Nicholson, A., 437. Niessl, G. v., 230. Niggl, M., 282. Nitrates, Fermentation of, 834. Nitrogen, Nutrient Fluids containing various Proportions of, Formation of Saccharomyces in, 540. Nitrous Oxide, Action of, on Vegetable Cells, 68. Noll, F. C., 889. Norner, C., 885. Norwegian North Sea Expedition, Holothuridea of, 791. Nose-piece for Binocular Prisms, 684. —— —, Watson’s Sliding-box, 106. Nostoe, Classification of, 93. -Nothnagel, H., 234. Notodelphyide, 506. Notthaft, J., 495. Nuclear- and Cell-division in the For- mation of the Pollen of Hemerocallis fulva, 809. Nucleated Blood-corpuscles, Differ- ential Staining of, 714. Differen- 931 Nuclei, Cell-, of Pinguicula and Utri- cularia, Crystalloids in, 366, — of Lieberkuehnia, 802. —, Staining, Flemming’s Modified Methods for, 715, 883. Nucleus, Cell-, and Chlorophyll, 69. —, Division of, in Spirogyra, 543. —— ——, in Chara feetida, 79. , in the Mother-cells of the Pollen of Liliacez, 366. of Living Infusoria, Staining, 280, 576. —— of the Salivary Cells of the Larve | of Chironomus, 185. Nuel, J. P., 26. Numerical Aperture, 151. Nutrient Fluids containing various pro- portions of Nitrogen, Formation of Saccharomyces in, 540. Nutrition of Lichens, 240. , Relation of, to the Distribution of the Sexual Organs on the Prothal- lium of Ferns, 374. O. Oberhauser’s Camera Lucida, 679. Obituary, 899. Objective, Gundlach’s 3-inch, 263. | ——, Powell’s 4. Oil-immersion, 565. ——,, Tolles’, with tapering front, 589, 904. Objectives, Achromatic, Colour-Correc- tions of, 109. , ——, Number of Lenses required in, 107. ——, Aperture of, 149. —, — of, Diaphragms for limiting, 407. ——, —— of, Iris Diaphragm for vary- ing, 262. ——,, Collar Correction of, 685. ——,, Dry and Immersion, Beck’s Achro- matic Condenser for, 270. _ —., High-power, Statoblasts of Lo- phopus crystallinus as a Test for, 129. —, Homogeneous - immersion and Water-immersion, 685. —— —, Correction adjustment for, 407, 854. —— —, Powell’s 3.-inch, 565. , Seratching the Front Lenses of, 264. —, Nelson’s Adapter for Rapidly Changing, 858. | ——, New Combination for, 551. | —— of Small and Large Aperture, 853. | ——, Penetrating Power of, 153. | ——, Verification of, 109. | —— with Large and Small Apertures, Relative Value of, 157. a ee 932 Occident Ants, 333. Oertel, 87. O’Hara, R., 838. Oil, Vegetation of Fungi in, 81. Olfactory Organ of Parmacella, 767. Olivier, L., 73, 640. Ollard, J. A., 273, 565, 587. Oniscoids, Aberrant, 777. Ontogeny of Fresh-water Copepoda, 776. Onuphis, Tubes of, Chemical Composi- tion of, 509. Oospores of Phytophthora infestans, 81. Ophiurida, Skeleton of, Development of, 55 Ophiuroidea, Nervous System of, 199. Ophiuroids, Structure and Development of, 789. Ord, W. M., 295. Organic Substances, Barff’s Preserva- tive for, 124. Organisms and Minerals, Distinctions between, 320. , Fossil, in Meteorites, 176. —,, Micro-, from Rainwater-Ice and Hail, 450. -——, Origin of the Lowest, 90. Oribatide, British, Further Notes on, 1. Origin of the Central Nervous System of the Annelida, 44. —— of the Embryo-sac and Functions of the Antipodal Cells, 64. —— of the Lowest Organisms, 90. Orley, L., 340. Orthonectida, 511, 624. Osborne, Lord 8. G., 787. Osmic Acid, Staining Tissues Treated with, 276. Ova, Ascidian, Test Cells in, 491. Ovaries of Actiniz, 795. Ovule, Homology of, 648, 808. of Primula, Development of, 647. Ovum of Melicerta, Development of, 53. Oxalate of Lime in Plants, 653. Oxides, Metallic, Absorption of, by Plants, 526. Oxygen, Disengagement of, by Hama- tococcus, 663. of, by Vegetable Cells in the Microspectrum, 661. —, Influence of, on the Development of the Lower Fungi, 376. Oyster, Development of, 330. ——,, Intestinal Parasites of, 804. ——,, Sexuality of, 606. ? P. Pacini, F., 701. Packard, A.S§., jun., 337, 503. INDEX. Paleontological Significance of the aa of Different Invertebrates, 4, Palates, Molluscan, Mounting, 746. Palmella, Relation of, to the Confer- vacese, 664. Paper Cells, 578. —, Semi-pulped Unglazed Print- ing, Simple Plan of Imbedding Tis- sues in, 474. Parabolic Reflector, Griffith’s, 266. Paraboloid, Bausch’s, 412. oe Modification of,’ 708. Parasite, Bacterial, of the Chinch Bug, 830. —, Cell-, of Frog’s Blood and Spleen (Drepanidium ranarum), 519. — of Malaria, 659. — on the Prothallium of Ferns (Com- pletoria complens), 377. —, Prolongation of Vegetative Ac- tivity of Chlorophyllian Cells under the Influence of, 93. Parasites, Intestinal, of Oysters, 804. , New, 345. — of the Kchiurida, 63. — of the Human Ear, 655. of the Saprolegniez, 828. Parasitic Character of Cases of Malaria, 659. — Hunicid, 190. — Fungi, 83. : —— Infusoria in Cephalopods, 63. — Nature of Cholera, 384. — — on the Vine, Roesleria hypogea, 229. — Organisms of Dressings, 384. Protozoa, 803. Parasitism of Puccinia Malvacearum, . Mode of, 80. — of Tuberculosis, 384. | Parker, A. T., 705. —.,, C. B., 724. —, W. N., 316. Parkes’ Class Microscope, 395. “ Drawing Room” Microscope,100. Parmacella, Olfactory Organ of, 767. Parona, C., 356. Parthenogenesis in the Bee, 608. —— in the House Spider, 614. Passage from the Root to the Stem, 74. Passages, Genital, of Asterias, 348. Pasteur, L., 238, 239. Paszlavszky, J., 823. Pathogenous Bacillus Water, 89. — Bacteria, 541. Pattern and Line Mounting, 718. Pax, F., 647, 808. Pea, Swelling of, 216. Pedicellarize, Structure of, 346. in Drinking INDEX. Pelagic and Deep-sea Fauna, 483. —— Fauna of Fresh-water Lakes, 765. Pelletan’s (J.) “Microscope Conti- nental,” 700. Penetrating Power of Objectives, 153. Penicillium, Influence of Light on the Growth of, 87. Pennock’s Oblique Diaphragm, 270. Penzig, O., 367, 538. Perenyi, J., 709. Peronospora viticola, 81. Peronospores and Saprolegniex, 230. Perrier, E., 347, 348. Perroncito, E., 191. Petromyzon Planeri, Development of, 26. Pettenkofer, M. v., 384. Peziza Sclerotiorum, Development of, 825. Pfeffer, W., 221. Pfitzner, W., 275, 583, 883. Phalangida, Anatomy of, 501. Phanerogamia, Embryology and His- tology of. See Contents. Pharmaceutical Solutions, Fungi in, 234, Phialidium variabile, Fission of, 59. Phillips, F. C., 526, —,, F. W., 799. Phosphorescence in Plants, 222. Phosphorescent Organs of Tomopteris, 780. Phosphorus, Mounting in, 134, 163, 579. Photographing, Collecting, and Stain- ing Bacteria, 571. Photographs of the Developmental Pro- cess in Birds, 23. — _, Woodward’s, of Amphipleura and Pleurosigma, 727. Photo-Micrography, 726. Phycomyces, Unobserved Sensitiveness in, 538. Phycomycetes, Sporangia of, Develop- ment of, 826. Phyllomic Nectar Glands in Poplars, 219. Phyllosiphon Arisari, 391. Phytoblasts and their Pseudopodia, 649. Phytophthora infestans, Oospores of, 81 Sclerotium of, Piesser, Dr., 494. Piffard’s Skin Microscope, 100. Pigment, Red, of Invertebrates (Tetro- nerythrine), 178. Pike, Spinal Cord of, Large Nerve- fibres in, 295. Pillsbury, J. H., 747. Pinguicula and Utricularia, Cell-nuclei of, Crystalloids in, 366, Pinkernelle, W., 700. 933 Pitchers of Cephalotus follicularis, 220. —— of Dischidia Rafflesiana, 651. — of Sarracenia and Darlingtonia, Epidermis of, 72. Pits, Bordered, Development of, 523. Planaria, Eyes of, 510. ——, Marine, Development of, 509. Plateau, F., 606. Platyhelminthes, Nervous System of, 194. ——, Relations of, 340. , Relationships of, with the Ccelen- terata and Hirudinea, 197. Pleurosigma and Amphipleura, Wood- ward’s Photographs of, 727. Podophthalmate Crustacea, Ampulle of, 505. Podostemonacesx, Structure of, 220. Poirier, J., 347, 348. Polarized Light as an addition to Staining, 426. Polarizing Microscopes, 672. Poli, A., 653. —, Plant-Crystals, 597. Pollen of Hemerocallis fulva, Cell- and Nuclear-Division in the Formation of, 809. of Liliacez, Cell-nucleus in the Mother-cells of, 366. Pollen-tubes, Cause of the Movement of, 650. ——, Formation of, 649. Pollock, W. H., 635. Polycolymna Stuarti, Stomata of, 524. Polyembryony in Mimosee, 65. Polygordius and Saccocirrus, Develop- ment of, 46. Polyps, Hydroid, Nervous System of, 202. Pyloric — ——,, Organization of, 793. Polytrichum, Male Fructification of, 823. Poplars, Phyllomic Nectar Glands in, 219. Porifera. See Contents. Postal Microscopical Society, Journal of, 421. Post-embryonic Development of Dip- tera, 37. Potassium, Iodide of, and Biniodide of Mercury, Mounting Objects in a solution of, and in Phosphorus, 163. Potonié, H., 225, 226. Potts, E., 350, 351, 515. Pouchet, G., 504. Powell, T., 621. Power and Aperture in the Microscope, Relation of, 300, 460. — of Eye-pieces, Measurement of, Powers, Magnifying, Table of, 105. Prantl, K., 226, 374, 533. 934 Prazmowski’s Micrometer Microscope, 547. Preparations, Dry, Method for, 705. , Durable, 120. Preparing Anthers, 122. Axis-cylinder, 703. Bacteria of Tuberculosis, 706. — Blastoderm of the Chick, 570. Diatoms, 707, 887. — Embryos of Insects, 570. —— Entomostraca, 439. — Foraminifera, 436. — Fossil Foraminifera, 886. — Fungi for the Herbarium, Herpel’s Method of, 122. —— Hemoglobin Crystals, 427. Nerve-fibrils of the Brain, 426. — Soft Tissues, 123. —— §Spicules, 886. — Stellate Hairs of Deutzia, 587. Tape-worms, 704. Preservation of Anatomical Specimens, 124. of Infusoria and other Micro- scopical Organisms, 279. Preservative, Barff’s, for Organic Sub- stances, 124. Fluids, 701, 866. Liquid, Wickersheimer’s, 427. Preserving and Killing Insects, 748. and Staining Tube-casts, 705. — Flowers, 428. — Hymenomycetes and Wild Flowers, English’s Method of, 283. — Infusoria, 706. — —— and Ameebe, 574. — Protozoa, 575. President’s Address, The, 145. Priapulus bicaudatus, 780. Prillieux, E., 70, 81. Primary Vessels in Aerial Organs, Order of Appearance of, 812. Primula, Ovule of, Development of, 647. Pringsheim, N., 220, 818. . Photo-chemical Microscope, 395. Prism, ‘“ Woodward,” Mounting for, 955. Prisms versus the Hemispherical Lens as Illuminators, 556. Proboscis of Lepidoptera, Structure of, ae Ov. Proceedings of the Society. See Con- tents. Prodrome of the Anthozoan Fauna of Naples, 57. Projecting an Image to any required Distance with Variable Amplification, Apparatus for, 677. Projection-microscopes, 673. Prolongation of Vegetative Activity of Chlorophyllian Cells under the Influ- ence of a Parasite, 93. INDEX. Proneomenia sluiteri, 31. Proscolex of Bilharzia heematobia, 51. _ Prothallium and Embryo of Azolla, 76. of Ferns, Parasite on (Completoria complens), 377. , Relation of Nutrition to the Distribution of the Sexual Organs on, 374. Protoplasm, Dead and Living, Chemical Difference between, 67, 361, 440, 522, 902. —— in Nerve-fibres of Unionide, Dif- ferentiation of, 767. — in Urtica urens, Properties of, 363. ——, killing of, by various Reagents, 522 , Living, Staining with Bismarck Brown, 278. of Aithalium septicum, Composi- tion of, 362. —— of Compound Laticiferous Tubes, 805. ——, Structure and Movement of, 804. , Studies of, 362. Protozoa. See Contents. Prudden, J. M., 128. Pseudomarginellida and Marginella, 604. Pseudopodia, Phytoblasts and their, 649. Psorospermie in Man, 357. , Oviform, or Coccidia, 643. Puccinia Malvacearum, Mode of Para- sitism of, 80. Pulsatoria, New Sub-class of Infusoria, 204. Pup and Larve of Diptera, 772. Pyenogonida, 335. Pyloric Ampulle of Podophthalmate Crustacea, 505. Pyrosoma, Ganglion and Ciliated Sac in, Development of, 769. Q. Quekett Microscopical Club, 861. R. Rabies, 239. Radial Tail-pieces, 557. Radiolaria, Skeleton of, 205. —— and Celenterates, “ Yellow Cells” "of, 244. Ralph, Dr., 590. Ranvier, L., 742. —— Microscope-lamp, 112. Myo-Spectroscope, 113. Rataboul, J., 122. Rathay, E., 80, 80. | Ravenala, Aril of, 216. INDEX. Red Pigment of Invertebrates (Tetro- nerythrine), 178. Rees, J. van, 636. Reflector, Griffith’s Parabolic, 266. , Impromptu Bramhall, 567. Refractive Indices, High,~ Mounting- media of, 156. Refractor, Gundlach’s Substage, 692, 869. Regel, K., 228. Rehm, 378. Reinitzer, F., 221. Reinke, J., 67, 361, 362, 362, 382, 525. Renaut, 27. _ Reniera filigrana, Development of, 798. Renson, G., 757. Repiachoff, W., 46. Report of Committee on Standard Gauges for Eye-pieces and Substages, 595. — of Council, 293. Reproductive Organs of Cycadez, 808. of Loranthacez, 363. of Vitrina, Abortion of, 330. Resinous Substances, Function of, 820. Resolution of Amphipleura pellucida, 584. Resolving-power, High, 416. Respiration, Intramolecular, Produc- tion of Heat by, 221. ‘ — of Detached Shoots, 815. of Plants, 651. Respiratory Movements of Insects, 606. Organs of Arachnids, 610. Resting-spores of Conferva, 836. Reyolying-table, Substitute for, 273. Rhizopoda, Geographical Distribution of, 356. Rhodope veranii, 491. Richard, 659. Richardson, B. W., Description of a Simple Plan of Imbedding Tissues for Microtome Cutting, in Semi- pulped Unglazed Printing Paper, 474. Richon, C., 80. Richter, K., 228. Riehm, G., 704, 705. Robin’s (C.) Dissecting Microscope, 101. Roboz, Z., 785. Rock Sections, Thin, Diatoms in, 246. Rodewald, H., 362. Roesleria hypogea, Parasitic on the Vine, 229. Rogers, W. A., 117, 285. Romanes, G. J., 635. Root-fibres, Cause of the Swelling of, 75. ——, Passage from, to the Stem, 74. Roots, Epidermal System of, 73. 935 Roots, Growing, Influence of a Galvanic Current on, 533. ——,, Hydrotropism of, 74. —— of Phanerogams, Apical Growth of, 650. —, Tips of, Darwin’s so-called “ Brain-function ” of, 529. Rosenbuseh’s Petrographical Micro- scope, 842. Rossbach, J., 541. Rosseter, T. B., 345. Rossler, R., 501, 521. Rostafinski, J., 664. ee New (Cupelopagis bucinedax), 9 Rotifers, Desiccation of, 787. ——, Eyes of, 512. Roumegutre, C., 827. Roux, 238, 239. Rowney, Prof., 360. Roy’s Microtome, 892. Royston-Pigott, G. W., 262. Rozsahegye, A., 839. Ruled Plates, Committee on, 861. Russow, E., 218, 523. Ss. Sabatier, A., 316. Saccharomyces apiculatus, 234. , Formation of, in Nutrient Fluids containing various Proportions of Nitrogen, 549. Saccocirrus and Polygordius, Develop- ment of, 46. Saffranin, Staining with, 275. Salensky, W., 24, 32, 618. Salicine Crystals, Mounting, 283. Saline Constituents of the Blood of Aquatic Animals, Influence of the External Medium on, 763. Salivary Cells of the Larye of Chiro- nomus, Nucleus of, 185. Salmon Disease, 538. Salpa, Development of, 32. Salpide, Embryonic Membranes of, 182. Salt, Eno’s Crystallised Fruit, 435. Salvia splendens, Fertilization of, 363. Sanderson, J. B., 533. Saprolegniez and Peronosporex, 230. , Parasites of, 828 Sarracenia and Darlingtonia, Epidermis of the Pitchers of, 72. Satterthwaite and Hunt's Freezing Section-cutter, 710. “Saw” of the Tenthredinide, Mount- ing, 276. Scales, Butterfly, Mounting, 277. of Insects mounted in Phos- phorus, 134. 936 Scent-glands of the Scorpion-spiders, 502. Schaarschmidt, G., 69. , J., 367, 6609. Schieck’s Microscope with Large Stage, 673. Schimper, A. F. W., 531. Schindler, F., 216. Schistocephalus and Ligula, 786. Schizeacez, 533. , Anatomy and Classification of, 226. Sehizomycete, Chromogeneous, on Cooked Meat, 655. Schizomycetes, Development of, In- fluence of Concussion on, 382. Schizophycex, 545. Schklarewski’s Hot-water Stage, 411. Schmidt, A., 249. —,, E., 805. Schmiedeberg, O., 509. Schneider, A., 643. Schnetzler, J. B., 88, 649, 655, 658, 664. Schrauer’s Microscope, 700. Schréder (H.) Projection Microscope, 673. Schullerus, J., 529. Schulthess, W., 781. Schultze, E., 223. Schultze’s Tadpole Slide, 110. Schulzer, S., 825. Schwartz, F., 223. Schwendener, S., 216, 531, 650. Schwendenerian Theory and Czno- gonium, 389. Sclerotium of Peziza Sclerotiorum, Development of, 825. Scoloplos armiger, Anatomy and His- tology of, 188. Scorpions, Habits of, 612. ——, Observations on, 774. Scott, D. H., 73. Scratching the Front Lenses of Homo- geneous-immersion Objeetives, 264. Screw-Collar Adjustment, Deby’s, 107. Scudder, P. H., 773. Seaman, W. H., 748. Secretion, Curious, in Gasteropods, 766. Secretory Glands, Structure of, 814. Section of “ Histology and Microscopy ” at the American Association, 119. Sedgwick, A., 179. Seeds and Fruits, Dispersion of, Me- chanical Contrivances for, 66. ——,, Distribution and Cross-fertiliza- tion of, 215. ——, Resistance of, to Extreme Cold, 66 Segmental Organs and Genital Gland of some Sipunculida, 47. in Isopoda, 337. Segmentation in the Mites, 614. INDEX. Segmentation, Maturation, and Fecun- dation of Limax campestris, 178. Segments, Youngest, and the Apical Cell, Energy of Growth of, 67. Seibert and Krafft’s Microscope, Im- provements in, 423. Seiler, C., 126, 899. Selenka, E., 509. Selvatico, S., 570. Sense-hairs of the Hydrachnida, 775. Sensitiveness, Unobserved, in Phyco- myces, 538. mage Davaine’s, Bacteria of, Series, Mounting Sections in, 888. Setz, Caudal, Cercaria with, 192. Sex, Influence of Food on, 30. Sexual Cells of Hydroida, 60. —— Organs on the Prothallium of Ferns, Relation of Nutrition to the Distribution of, 374. Sexuality of the Oyster, 606. Sharp, H., 718. Shoots, Detached, Respiration of, 815. Shore, T. W., 621. Shorthand, Attempt to apply, to Sponges, 61. Shurley’s Improved Slide for the Ex- amination of Gaseous Matter, 551. Sidle & Co”s Acme Class Microscope, 201. — Centering Substage, 555. — & Kain’s Mechanical Fimgers, 721. Sieber, N., 538. Sieve-tubes, 370. —— ——, Callus-plates of, 218. Sight, Sensations of, Conveyed by the Facet-eye, 494. Sign x, True Meaning of, 423, 564, 746, 864. Sigsworth, 446. Silk Thread Movement, Ulmer’s, 406. Silliman, W. A., 192. Silver Nitrate, Staining with, 275. Silvered Convex Lenses v. Concave Mirrors, 692. Simroth, H., 767. Siphonesx, Fossil, 394. Siphonophora of the Bay of Naples, 204. ——, Tissues of, 632. Sipunculus nudus, Anatomy and His- tology of, 48. Size, Apparent, of Magnified Objects, 861 Skeleton, Calcareous, of Asteroides, Development of, 514. — of Madrepores, 795. —— of the Ophiurida, Development of, 55 —— — Radiolaria, 205. ——, Spicular, Infusorian with, 355. INDEX. Slide-carrier and Glass Stage, Bausch and Lomb’s, 687. Slide, New Growing or Circulation, 19. ——, Schultze’s Tadpole, 110, ——, Shurley’s Improved, for the Ex- amination of Gaseous Matter, 551. ——,, Stokes’s Tadpole, 110. Slides and Covers, Cleaning Used, 583. ——, Cabinet for, 747. ——,, Labelling, 287. ——,, Smith’s, 127. Sluiter, C. P., 47. Small Objects, Cutting Sections of, 126. att ——, taking up by Suction-tubes, 00. Smell, Sense of, in Actinie, 635. Smith, A., 400. —, H. L., 247, 417, 547. —., J. E., 555. , 8. J., 617. Soft Parts, Eau de Javelle for Remoy- ing, 889. — Tissues, Method of Preparing and Mounting, 123. Soil, Influence of Warmth of, on the Cell-formation of Plants, 70. Solger, B., 794. Solms-Laubach, Count, 393. Soltwedel, F., 214. Sorby, H. C., 578. Spatangus purpureus, Anatomy of, 627. Spectral (Micro-) Apparatus, Engel- mann’s, 661. Spectroscope, Myo-, Ranvier’s, 113. Spectrum (Micro-), Disengagement of Oxygen by Vegetable Cells in, 661. Spengel, J. W., 190, 619. Spermatogenesis in Mammalia, 757. —— in Vertebrates and Annelids, 316. Spermatozoa of Hydrozoa, 60. Spermatozoids, Structure and Mode of Formation of, 364. Sphagnacex, Classification of, 79, 653. Sphagnum, Vegetative Reproduction of, 228. Sphere, Hollow Glass, as a Condenser, 112, 273, 274. Sphero-crystals, 367, 815. Spherules and Threads, Black Annuli and Lines of, 696. Spicular Skeleton, 355. Spicules found in the Ambulacral ee of the Regular Echinoidea, ——,, Preparing, 886. Spider, Furrow, Nest-forms of, 613. ——, House, Parthenogenesis in, 614. Spiders, Liver of, 39. ——,, Scorpion-, Scent-glands of, 502. —— Webs, 337. Infusorian with, 937 Spiders’ Webs, Threads of, 170. Spinal Cord of the Pike, Large Nerve- fibres in, 295. Spine, Caudal, of Limulus, Function of, 41 Spines of Asteroidea, 57. Spiral Cells in Crinum and Nepenthes, 8138. Spirogyra, Division of the Cell-nucleus in, 543. Sponges. See Contents—Porifera. Spongilla and Hydra, Chlorophyll-cor- puscles and Amyloid Deposits of, 322 Spongiophaga in Fresh-water Sponges, 350. Sporangia and Spores of Isoetes, De- velopment of, 78. ——,, Development of, 224. —— of the Phycomycetes, Develop- ment of, 826. Spores and Sporangia of Isoetes, De- velopment of, 78. ——,, resting-, of Conferva, 836. Sporogonium, Branched, of a Moss, 534. Spring-Clip Board, 128. ——, Nassau Adjustable Spiral, 725. —— Paper-Clip for fastening Card Cells upon Slides, 446. Sputa, Examination of, 728. Stage, Bulloch’s Diatom, 554. —, Glass and Slide-carrier, Bausch and Lomb’s, 687. —— Heating Apparatus, Julien’s, 266. ——, Hot or Cold, Symons’, 21. ——., Hot-water, Schklarewski’s, 411. Stahl, E., 373. Staining, 568, 873. — and Preserving Tube-casts, 705. Bacillus tuberculosis, 895. ——, Differential, of Nucleated Blood- corpuscles, 714. —, Double, with Carmine and Anilin Green, 576. —— Living Protoplasm with Bismarck Brown, 278. — Nuclei, Flemming’s Method for, 715, 883. — Nucleus of Living Infusoria, 280, 576. - ——, Photographing and Collecting Bacteria, 571. ——, Polarized Light as an Addition to, 426. —— Tissues treated with Osmic Acid, 276. — with Magdala-red, 885. —— with Saffranin, 275. — with Silver Nitrate, 275. Stallybrass, H. M., 274. _ Stand, The Model, 102. Standard for Micrometry, 114. 938 Stapelia, Stomata of, 372. Starch, Change of, into Sugar at Low Temperatures, 821. Starch-grains, Growth of, by Intussus- ception, 70. , structure of, 368. Starch, Maize-, Fermentation of, 833. , Transformation of, 222. Starfishes, Circulating Apparatus of, 347. Statoblasts of Lophopus crystallinus as a Test for High-power Objectives, 129. Steenbach, C., 584. Stein’s Small Microphotographic Appa- ratus, 113. Steiner, J., 389. Steinheil’s-Achromatic Eye-pieces, 551. Stem of Dicotyledonous Woods, Decom- position of Calcium Carbonate in, 527. , Passage from the Root to, 74. Stephanoceros Eichornii, Tube of, 345. Stephenson, J. W., 134, 286. ——, On Mounting Objects in Phos- phorus and in a Solution of Biniodide of Mercury and Iodide of Potassium, 163. Stereoscopic (Micro-) Vision, 154. with Non-stereoscopic Bin- ocular Arrangements, 271. Sterigmatocystis, 80. Sternaspis, 48. Sternberg, G. M., 235, 571. Stilling, J., 426. Stinging-cells of Coelenterata, Cha- racters of, 200. Stocker, G., 428. Stodder, C., 904. Stokes, A. W., 884. Tadpole-Slide, 110. Stomata in a Fossil Plant, 813. ra the Leaf-Stalk of Filicines, 226. j — of Polycolymna Stuarti, 524. — of Stapelia, 372. —, Structure and Functions of, 372. —, and Mechanics of, 216. Stowell, C. H., 100. Strasbureer, E., 810. Strasser, H., 126. Straus, 661. Strepsiptera, Nervous System of, 499. Striation, Fineness of, as a Specific Character of Diatoms, 247. Stringfield, W., 128. Sturgeon, Development of, 24. Sturt, T. J., 704. Substage and Eye-pieces, Standard Gauges for, Report of Committee on, 595, 700. —— Fine-adjustment, 554. INDEX. Substage Refractor, Gundlach’s, 692. , Sidle’s Centering, 555. ——,, Swinging, or “Swinging Tail- piece,” 111. Subterranean Blind Crustacea in New Zealand, 778. Suction-tubes, taking up small objects ry, 900. Suffolk, W. T., 404. Sugar, Change of Starch into, at Low Temperatures, 821. Summary of Current Researches. Contents. Swelling of Root-fibres, Cause of, 75. of the Pea, 216. Swift and Son’s Improved Microtome, 432. — — Petrological Microscope, 849. See Tank Microscope, 549. Swim-bladder-like Organs in Anne- lids, 44. “Swinging Substage” or “Swinging Tail-piece,” 111. Tail-pieces, Value of, 111. Symbiosis of Algee with Lower Ani- mals, 542. : — of Animals and Alge, 840. with Plants, 241, 322. of Dissimilar Organisms, 597, 764. Symbols, Minks’ Licheno-mycological, 542. j Symmetrical Mlumination, 691. Symons, W. H., On a Hot or Cold Stage for the Microscope, 21. Synascidian, New, 331. Systematic Position of Balanoglossus, 194. T. Table of Magnifying Powers, 105. , Revolving, Substitute for, 273. Tactile Corpuscles, Nerve-endings of, 28. Tadpole Slides, Schultze’s and Stokes’, 110. —— Tail, examining Circulation of Blood in, 438, 565, 566. “Tail-piece, Swinging,” or “ Swinging Substage,” 111. Tail-pieces, Radial, 557. , Swinging, Value of, 111. Tangl, H., 543, 809. Tape-worms, Preparing, 704. Taste, Location of, in Insects, 607. Taylor, G. C., 866. , Lt. W., 576. Teasdale, W., 438. — Field Naturalist’s Microscope,549. Teichmann’s (L.) Injection-mass, 125, 716. Temnopleuridx, Histology of, 443. INDEX. Temperatures, Low, Change of Starch into Sugar at, 821. Tenthredinidse, Saw of, Mounting, 276. Test for High-power Objectives, Stato- blasts of Lophopus crystallinus as, 129. —— -Cells in Ascidian Ova, 491. —— -Plate, Fasoldt’s, 415. (Tetronerythrine), Red Pigment of In- vertebrates, 178. Textile Fabrics, Microscopical Exami- nation of, 732. Thallus of Marchantia, Influence of Light on, 534. of Usnea articulata, 240. Thames Mud, Diatoms of, 94. Thanhoffer, L. v., 33. Trrigation Knife, 713. Thelyphonus, Scent-glands of, 502. Thomas, 236. Thomas’ (C.) Vivarium, 688. Thread Movement, Ulmer’s Silk, 406. Threads and Spherules, Black Annuli and Lines of, 696. of Spiders’ Webs, 170. Thuillier, 239. Thuret, 93. Tieghem, P. Van, 81, 87. Tolles’ Objective, with Tapering Front, 589, 904. Tomaschek, A., 650. Tomopteris, Phosphorescent Organs of, 780. Toussaint, H., 239, 384. Tracks of Invertebrates, Palzeonto- logical Signification of, 324. Transactions of the Society. Contents. Transformation of Starch, 222. Transpiration, Physiological Functions of, 221. Treasurer’s Account, 292. Trécul, A., 812-13. Treffner, E., 375. Trelease, W., 219, 363. Trematodes rag br aan to Environment in, 784. , Structure of, 782. , Vascular Organs of, 784. Treub, M., 363, 643, 651, ’808. Trichina Examinations, 728. Trichinsee, Entozoa confounded with, 342. Trichinoscope, Bausch and Lomb, 258. Triest, Sponges of Gulf of, 350. Trilobites, Organization of, 508. Triton, Genesis of the Egg i in, 479. Trypanosoma, Development of, 520. Tschirch, A., 372, 817. Tube of Stephanoceros Hichornii, 345. vie -casts, Staining and Preserving, 70 See 939 Tubes, Ambulacral, of the regular Echinoidea, Spicules found in, 297. of Onuphis, Chemical Composi- tion of, 509. Tubercular Disease, Etiology of, 385. Tuberculosis, Bacteria of, Ehrlich’s Method of Exhibiting, 572. —, Experimental, 385. —, Parasitism of, 384. , Preparing Bacteria of, 706. Tubularia cristata, Development of, 634, Tunicata of the ‘Challenger,’ 33. Turbellaria, Excretory Apparatus of, 344. , New Type of, 192. Turntable, Bausch and Lomb’s, 284, 431. Turpentine, Venice, as a Cement, 724. Type, Diversity of, in Ancient Myria- pods, 773. ——, New, of Turbellaria, 192. U. Ulivi, G., 608. Uljanin, B., 768. Ulmer’s Silk Thread Movement, 406. Underhill, H. M. J., 438. Unionide, Differentiationof Protoplasm in Nerve-fibres of, 767. Unpressed Mounting, 884. Uredinex, Alternation of Generations in, 80. Urtica urens, Properties of the Proto- plasm in, 363. Urticacese, Histology of, 219. Usnea articulata, Thallus of, 240. Ussow, M., 328. Ustilaginies, 536. Utricularia and Pinguicula, Cell-nuclei of, Crystalloids in, 366. V. Vaccinal Micrococci, 661. Vaccination, Anthrax-, Experiments on Pasteur’s Method of, 238. ——- for Fowl-cholera, New Method of, 239. Vacuole, Contractile, of Vorticella, Vacuum-bubbles in Canada Balsam, o81. Valle, A. Della, 768. Vampyrella, 544, 840. Varenne, A. de, 60. Variation in Asterias glacialis, 513. Varnish, Dammar, 583. Vascular System of Naiades and My- tilide, 605. 940 INDEX. Vejdovsky, F., 48. Wasserlein’s Saccharometer Micro- Venice Turpentine as a Cement, 724. scope, 399. Verification of Objectives, 109. Vermes. See Contents. Verrill, A. E., 604. Vertebrata, Embryology and Histology of. See Contents. Vertical Illuminator for Examining Histological Elements, 266. —— ——, Hitchcock’s Modified Form of, 409. Vesque, J., 651. Vessels, Laticiferous, 73. Viallanes, H., 34, 37, 38. Vialleton, L., 767. Vickers, G. W., 748. Viet, C., 651. Vigelius, W. J., 769. Vignal, W., 603. Villot, A., 784. Vine, Aubernage, a Disease of, 827. —, Mal Nero of, 229, 827. ——, Roesleria hypogzea parasitic on, 29 229, Vision, Abbe Theory of Microscopical, 147. ——, Binocular, in the Microscope, 692. ——, Depth of. Penetrating Power of Objectives, 153. —, Micro-Stereoscopic, 154. , with Non-stereoscopic Bin- ocular Arrangements, 271. Vitrina, Reproductive Organs of, Abor- tion of, 330. Vivarium, Thomas’, 688. Vogel, A., 819. Vogt, C., 176, 320. “ Volvox,” 438. Volvox, Mounting, 436, 585, 586, 746. Vorce, C. M., 394, 546. Vorticella, Contractile Vacuole of, 355. Vorticelle, Species of, 636. Vosmaer, G. C. J., 61, 797. Vries, H. de, 819, 820. W. Waechter’s Class or Demonstrating Microscope, 398. Travelling Dissecting Microscope, 677. Walker, J., 577. Walmsley, W. H., 578. Walz, R., 338. Warming, E., 220. Warmth of the Soil, Influence of, on the Cell-formation of Plants, 70. Warnstorf, C., 228. Warren, R. S., 707. Wartmann, E., 66. Wash-bottle, Filtering, 746. Water- and Homogeneous-immersion Objectives, 685. ——, Causes of the Movement of, in Plants, 373. — -Distribution in Plants, 373. ——, Drinking, Impurities of, caused by Vegetable Growth, 394. eR ——, Pathogenous Bacillus in, 89. ——, Examination of, 250. ——, Excretion of, on the Surface of Nectaries, 223. ——, Potable, Destruction of Micro- scopical Organisms in, 585. Watson, C. J., 287. Watson’s Sliding-box Nose-piece, 106. Wax and Guttapercha in Dry Mount- ing, 285. Cells, 578. Wead, C. K., 687. Weber, M., 777. Webs, Spiders’, 337. ——, Threads of, 170. Wedl, C., 427. Weismann, A., 60, 203. Wenham’s (F. H.) Universal Inclining and Rotating Microscope, 255, 400. West, T., 559. Westermaier, M., 67, 227, 524. Wheat-flour, Microscopical Examina- tion of, 584. White, T. C., 427, 438. , New Growing or Circulation Slide, 19. White and Monochromatic Light, Air- bubbles and Fat-globules in, Ap- pearances presented by, 742. — Corpuscles of the Blood, 27. Sea, Protozoa of, 213. Whitelegge, T., 578. Whitman, C. O., 866. Wickersheimer’s Preservative Liquid, 427. : Wiesner, J., 529, 531. Wightman, G. J., 435. Wikszemski, A., 275. Wild Flowers and Hymenomycetes, . English’s Method of Preserving, 283. Wille, L., 836. Williams’ Freezing Microtome adapted for use with Ether, 430. Wilson, W. P., 223. Windler’s Microtome, 711. Wings of Insects, 35. Wisselingh, C. van, 812. Wolff, W., 758. Wood, J. T., 900. Woods, Fossil Coniferous, Sections of, 131, INDEX. Woods, Dicotyledonous, Stem of, De- composition of Calcium Carbonate in, 527. Wood-Mason, J., 489, 501. Woodward, J. J., 114. ——,, Photographs of Amphipleura and Pleurosigma, 727. “Woodward” Prism, Mounting for, 555, Wool-measurer, Bohm’s, 859. Wooster, W. H., 567. Woronin, M., 536. Wortmann, J., 829. Wright, L., 862. Wywodzen’s Injecting Material, 717. 941 ¥ Yeast, Destruction of Insects by, 378. “Yellow Cells” of Radiolarians and Coelenterates, 244, Yung, E., 30. Z. Zacharias, E., 364. Zeiller, R., 813. Zenger, C. V., 551. Zimmermann, A., 66, 534. Zoology. See Contents. Zopf, W., 376, 545. LONDON: PRINTED BY WILLIAM CLOWES AND SONS, LIMITED, STAMFORD STREET AND CHARING CROSS. - | | | 3 5185 00266 7895 | ith a 2 tRagh Le oe ot ltl New York Botan I