R oV %0 Iftbrarg of tin Stusmtm OF COMPARATIVE ZOOLOGY, AT HARVARD COLLEGE, CAMBRIDGE, MASS. Journal OF THE Royal Microscopical Society; CONTAINING ITS TRANSACTIONS AND PROCEEDINGS, AND A SUMMARY OF CURRENT RESEARCHES RELATING TO ZOOLOGY 1ST ID BOTANY (principally Invertebrata and Cryptogamia), MICROSCOPY, eSco. Edited by P. JEFFREY BELL, M.A., One of the Secretaries of the Society , and Professor of Comparative Anatomy and Zoology in King's College ; WITH THE ASSISTANCE OF THE PUBLICATION COMMITTEE AND A. W. BENNETT. M.A., B.Sc., F.L.S., J. ARTHUR THOMSON, M.A., Lecturer on Botany at St. Thomas’s Hospital , * Lecturer on Zoology in the School of Medicine , R. G. HEBB, M.A., M.D. (Cantab.), and Edinburgh, FELLOWS OF THE SOCIETY. FOR THE YEAR 1891. Part 1. PUBLISHED FOR THE SOCIETY BY WILLIAMS & NORGATE, ^LONDON AND EDINBURGH. Journal OF THE Royal Microscopical Society; CONTAINING ITS TRANSACTIONS AND PROCEEDINGS, AND A SUMMARY OF CURRENT RESEARCHES RELATING TO ZOOILOG-^ BOTANY (principally Invertebrata and Cryptogamia), MICROSCOPY, <3cc. Edited, by F. JEFFREY BELL, M.A., One of the Secretaries of the Society and Professor of Comparative Anatomy and Zoology in King's College ; WITH THE ASSISTANCE OF THE PUBLICATION COMMITTEE AND A. W. BENNETT, M.A., B.Sc., F.L.S., Lecturer on Botany at St. Thomas’s Hospital, R. G. HEBB, M.A., M.D. ( Cantab .), and J. ARTHUR THOMSON, M.A., Lecturer on Zoology in the School of Medicine, Edinburgh, FELLOWS OF THE SOCIETY. FOR THE YEAR 1891. PUBLISHED FOR THE SOCIETY BY WILLIAMS & NORGATE, LONDON AND EDINBURGH. THE (Established in 1839. Incorporated .by Royal Charter in 1866.) The Society was established for the promotion of Microscopical and Biological Science by the communication, discussion and publication of observa- tions and discoveries relating to (1) improvements in the construction and mode of application of the Microscope, or (2) Biological or other subjects of Microscopical Research. It consists of Ordinary, Honorary, and Ex-officio Fellows, without distinction of sex. Ordinary Fellows are elected on a Certificate of Recommendation, signed by three Ordinary Fellows, setting forth the names, residence, and description of the Candidate, of whom the first proposer must have personal knowledge. The Certificate is read at two General Meetings, and the Candidate balloted for at the second Meeting. The Admission Fee is £2 2s., and the Annual Subscription £2 2-s., payable on election, and subsequently in advance on 1st January annually, but future payments may be compounded for at any time for £31 10s. Fellows elected at a meeting subsequent to that in February are only called upon for a proportionate part of the first year’s subscription, and Fellows permanently residing abroad are exempt from one-fourth of the annual subscription. Honorary Fellows (limited to 50), consisting of persons eminent in Microscopical or Biological Science, are elected on the recommendation of five Ordinary Fellows and the approval of the Council. Ex-officio Fellows (limited to 100) consisting of the Presidents for the time being of any Societies having objects in whole or in part similar to those of the Society, are elected on the recommendation of ten Ordinary Fellows, and the approval of the Council. The Council, in whom the management of the property and affairs of the Society is vested, is elected annually, and is composed of the President, four Vice-Presidents, Treasurer, two Secretaries, and twelve other Ordinary Fellows. The Meetings are held on the third Wednesday in each month from October to June, at 20, Hanover Square, W. (commencing at 8 p.m.). Visitors are admitted by the introduction of Fellows. In each Session two additional evenings are devoted to the exhibition of Instruments, Apparatus, and Objects of novelty or interest relating to the Microscope or the subjects of Microscopical Research. The Journal, containing the Transactions and Proceedings of the Society, and a Summary of Current Researches relating to Zoology and Botany (principally Invertebrata and Cryptogamia), Microscopy, &c., is published bi-monthly, and is forwarded post-free to all Ordinary and Ex-officio Fellows residing in countries within the Postal Union. The Library, with the Instruments, Apparatus, and Cabinet of Objects, is open for the use of Fellows daily (except Saturdays) from 10 a.m. to 5 p.m. It is closed for four weeks during August and September. Forms of proposal for Fellowship , and any further information , may he obtained by application to the Secretaries , or Assistant- Secretary, at the Library of the Society, 20, Hanover Square, W. CL 2 HIS ROYAL HIGHNESS ALBERT EDWARD, PRINCE OF WALES. E.G., G.C.B., F.R.S., &c. residents. Elected. Sir Richard Owen, K.C.B., D.C.L., M.D., LL.D., F.RS. 1840-1 •John Lindley, Ph.D., F.R.S 1842-3 •Thomas Bell, F.R.S 1844-5 *James Scott Bowerbank, LL.D., F.R.S. ... 1846-7 •George Busk, F.R.S 1848-9 • Arthur Farre, M.D., F.R.S 1850-1 •George Jackson, M.R.C.S 1852-3 * William Benjamin Carpenter, C.B., M.D., LL.D., F.R.S. . 1854-5 George Shadbolt 1856-7 •Edwin Lankester, M.D., LL.D., F.R.S 1858-9 •John Thomas Quekett, F.R.S 1860 •Robert James Farrants, F.R.C.S 1861-2 •Charles Brooke, M.A., F.R.S 1863-4 James Glaisher, F.R.S 1865-6-7-8 *Rev. Joseph Bancroft Reade, M.A., F R.S 1869-70 •William Kitchen Parker, F.R.S 1871-2 •Charles Brooke, M.A., F.R.S 1873-4 Henry Clifton Sorby, LL.D., F.R S 1875-6-7 Henry James Slack, F.G.S 1878 Lionel S. Beale, M.B., F.R.C.P., F.R.S 1879-80 •P. Martin Duncan, M.B., F.R.S 1881-2-3 Rev. W. H. Dallinger, LL.D., F.R.S 1884-5-6-7-8 Charles T. Hudson, M.A., LL.D. (Cantab.) 1889-90-91 Deceased. COUNCIL. Elected 21st January, 1891. |)rcsibcni Robert Braithwaite, Esq., M.D., M.R.C.S., F.L.S. Uicc-pn.'sibcnf'i. *Prof. J. William Groves, F.L.S. Albert D. Michael, Esq., F.L.S. *Prof. Charles Stewart, Pres. L.S. Charles Tyler, Esq., F.L.S. treasurer. *Frank Crisp, Esq., LL.B„, B.A., Y.P. & Treas. L.S. jSimtarus. Prof. F. Jeffrey Bell, M.A. Rev. W. H. Dallinger, LL.D., F.R.S. ©rbmanr Members (LCmmciL (<> 'OO' Prof. Lionel S. Beale, M.B., F.R.C.P., F.R.S. Alfred W. Bennett, Esq., M.A., B.Sc., F.L.S. James Glaisher, Esq., F.R.S., F.R.A.S. Richard G. Hebb, Esq., M.A., M D. Charles T. Hudson, Esq., M.A., LL.D. (Cantab.), F.R.S. George C. Karop, Esq., M.R.C.S. Thomas H. Powell, Esq. Prof. Urban Pritchard, M.D. Walter W. Reeves, Esq. William Thomas Suffolk, Esq. Frederic II. Ward, Esq., M.R.C.S. librarian antr Assistant Secretary. Mr. W. FI. Brown. * Members of the Publication Committee. CONTENTS Transactions of the Society — page I. — Some Observations on the Various Forms of Human Sperma- tozoa. By It. L. Maddox, M.D., Hon. F.R.M.S. (Plate I.) Part 1 1 II. — The President’s Address on some Doubtful Points in the Natural History of the Rotifera. By C. T. Hudson, LL.D., F.R.S. .. ,, 6 III. — Report on an Earthworm collected for the Natural History Department of the British Museum, by Emin Pasha, in Equatorial Africa. By W. B. Benham, D.Sc. (Plates III. and IV.) Part 2 161 IV. — New and Foreign Rotifera. By Surgeon V. Gunson Thorpe, R.N., F.R.M.S. (Plates VI. and VII.) Part 3 301 V. — A New Method of Infiltrating Osseous and Dental Tissues. By T. Charters White, M.R.C.S., F.R.M.S „ 307 VI. — On Bull’s-eyes for the Microscope. By E. M. Nelson, F.R.M.S. (Figs. 32-35) „ 309 VII. — On the Structure of certain Diatom-valves as shown by sec- tions of charged specimens. By C. Haughton Gill, F.C.S., F.R.M.S. (Plate VIII.) Part 4 441 VIII.— A New Illuminating Apparatus. By E. M. Nelson, F.R.M.S. (Figs. 51 and 52) „ 443 IX. — The Foraminifera of the Gault of Folkestone. — I. By Frederick Chapman. (Plate IX.) Part 5 565 X. — Notes of New Infusoria from the Fresh Waters of the United States, By Dr. Alfred C. Stokes. (Plate X.) Part 6 697 XI. — On an Improved Method of making Microscopical Measure- ments with the Camera Lucida. By Sir Walter Sendall, K.C.M.G.,M, A., F.R.M.S. (Figs. 77-80) „ 705 Summary of Current Researches relating to Zoology and Botany (princi- pally Invertebrata and Cryptogamia), Microscopy, &c., including Original Communications from Fellows and Others.* 19, 169, 315, 447, 576, 710 ZOOLOGY. A. — Vertebrata : — Embryology, Histology, and General, o. Embryology. PAGE Gulick, J. T. — Preservation and Accumulation of Cross- Infertility .. .. Part 1 19 Hertwig, O. — Experimental Studies on Ova ,, 19 Holl, M. — Maturation of the Ovum of the Foul ,, 20 Tarulli, L. — The Pressure within the Egg of the Fowl „ 21 Spencer, W. B. — Formation of a Double Embryo in the Hen’s-egg . . . . „ 12 Rossi, O. — Maturation of Amphibian Ova n 21 Paladino, G. — The Formation of the Zona pellucida „ 22 Mitsukuri, K. — Foetal Membranes of Chelonia ,, 22 * In order to make the classification complete, (1) the papers printed in the 1 Transactions,’ (2) the abstracts of the ‘ Bibliography,’ and (3) the notes printed in the ‘ Proceedings ’ are included here. Vlll CONTENTS. PAGE Kollmann, J. — Formation of the Notochord in the Human Embryo .. Kuborn, P. — Development of Vessels and Blood in the Embryonic Liver Semon, R. — Relation of Mesonephros to the Pronephros and Supra-renal Bodies AYiedersheim, R. — Urinogenital Apparatus of Crocodiles and Chelonians . . Janosik, J. — Development of the Reproductive System Coggi, A. — Sti'ucture of Nervous Cells Minot, C. S. — Morphology of Blood-corpuscles „ „ Fate of the Human Decidua reflexa Heape, AY. — Transplantation and Growth of Mammalian Ova within a Uterine Foster-mother Kastschenko, N. — Maturation of the Ova of Elasmobranchs Schneider, A. — Early Stages in Development of Elasmobranchs Ryder, J. A. — Yolk-sac of Young Toad-fish Corning, H. K. — The Origin of Blood from the Endoderm Minot, C. S. — Theory of the Structure of the Placenta Selenka, E. — First Stages of Placental Union in Man „ „ Development of Apes Hubrecht, A. A. AY. — Development of Germinal Layers in Sorex Spencer, AY. B. — Nomenclature of Chicken Embryos for Teaching Purposes AYiedersheim, R. — Development of Salamanda atra .. Cunningham, J. T. — Disputed Points in Teleostean Embryology AVilley, A. — Later Larval Development of Amphioxus Roule, L. — Development of Muscular Fibres Paterson, A. M. — Development of Sympathetic Nervous System in Mammals Schottlaender, T. — Degeneration of the Follicle in the Mammalian Ovary Fol, M. H. — Fecundation Klebs, E. — Comparative Anatomy of Placenta Henricius, Gr. — Placenta of the Cat AArENCKEBACH, K. F. — Gastrulation in Lacerta agilis Mitsukuri, K. — Foetal Membranes in Chelonia AVaters, B. H. — Primitive Segmentation of Vertebrate Brain Lameere, A. — Origin of Vertebrata Zeller, E. — Fertilization of Newts Cholodkovsky, N. — The Blastopore in Meroblastic Ova Voeltzkow, A. — The Eggs and Embryos of the Crocodile Froriep, A. — Development of the Optic Nerves Lachi, P. — Histogenesis of the Neuroglia Van der Stricht, O. — Development of Blood in Embryonic Liver Holl, M. — Maturation of the Egg-Cell of the Fowl Field, H. H. — Development of Pronephros and Segmental Duct in Amphibia Morgan, J. H. — Breeding and Embryology of Frogs Ryder, J. A. — Development of Eng y stoma Holt, E. AV. L. — Egg and Larvse of Teleosteans Goldberg, M. — Development of Ganglia in the Fowl Janosik, J. — Development of the Genital System Vejdovsky, F. — Phenomena of Fertilization Part 1 V 99 99 99 Part 2 55 55 55 Part 3 55 55 55 55 55 5* Part 4 55 Part 5 55 99 55 Part 6 55 55 55 55 55 55 55 22 23 23 23 24 24 25 169 169 170 170 170 171 315 315 316 317 318 318 318 319 320 321 322 447 448 448 449 449 449 576 576 577 577 578 578 578 710 711 712 712 713 713 713 713 B. Histology. Fromm ann, C. — Streaming Movements of Protoplasm Schneider, K. C. — Cell-Structure Part 2 171 CONTENTS. IX Ryder, J. A. — Methods of Contractility in Filaments of Protoplasm .. Hoyer, H. — Suitable Object for Study of “ Direct ” Nuclear Division.. Flemming, W. — Attraction- Spheres and Central Bodies in Tissue and Migratory Cells Ranvier, L. — Clasmatocytes „ „ Transformation of Lymphatic Cells into Clasmatocytes .. Auerbach, L. — Two Kinds of Chromatin „ „ Red Blood-corpuscles of Amphibians Gulland, G. Lovell — Nature and Varieties of Leucocytes Blanchard, R. — Evacuation of Cell-nuclei Kolliker, A. von — Structure of the Spinal Cord in Human Embryos Ambronn, H. — Optical Characters of Medullated and Non-medullated Nerve • Fibres Dubern, G. — Histology of Spermatozoa Schafer, E. A. — Structure of Amoeboid Protoplasm Macallum, A. B. — Morphology and Physiology of the Cell Goppert, E. — Indirect Fragmentation Muller, H. F. — History of Blood-corpuscles Lwoff, B. — Origin of the Fibrillse in Connective Tissue Schneider, C. 0. — Structure of the Cell , Solger, B. — Pigment-cells Ballowitz, E. — Minute Structure of Spermatozoa of Mammalia Auerbach, L. — Difference between the Nuclei of Male and Female Repro- ductive Elements Flemming, W. — Structure and Division of the Cell Solger, B. — The “ Intermediate Body ” in Cell-division Hermann, E. — Origin of the Karyokinetic Spindle Heidenhain, M .—Central Corpuscles in Attraction- Spheres Burger, O. — Attraction-Spheres in Coelomic Cells .. Flemming, W. — Division of Leucocytes Haycraft, J. B., & A. Rollett — Structure of Striped Muscle Magini, G. — Structure of Nerve-cells .. .. Zoja, R. & L.— Bioplasts or Plastidules Part 2 99 Part 3 99 99 99 99 99 99 99 99 Part 4 it 99 Part 5 99 99 Part 6 99 99 99 99 99 y. General. Parker, T. J. — Biological Terminology .. .. Part 2 Preyer, J. — Anabiosis „ Penard, E. — Chlorophyll in the Animal Kingdom „ Shore, T. W. — Origin of the Liver ^ „ Klebs, R. — Fauna of Amber ,, Haeckel, E. — Plankton- Studies Part 3 Julien, A. — Position of Nerve-Centres „ Cox, C. F. — Protoplasm and Life ,, Parker, T. Jeffery — Elementary Biology Part 4 Schimkewitsch, W. — Classification of Animal Kingdom . . „ Morgan, C. Lloyd — Nature and Origin of Variations Part 6 Imhof, O. E. — Exploration of Lakes .. .. „ „ B. — Invertebrata. Leidy, J, — Parasites of Mola rotunda Part 1 v „ • Notices of Entozoa Part 2 PAGF. 172 173 322 323 323 324 324 324 324 325 325 325 450 450 451 451 451 579 580 580 714 714 715 715 715 715 716 716 716 717 173 173 174 174 174 326 326 326 451 452 717 717 25 175 X CONTENTS. ] Greenwood, M. — Action of Nicotin on Invertebrates Part 3 Roule, L. — The Trocliozoa jy Benham, W. B. — Abnormalities in Crayfish and Earthworm „ Korotneff, A. — Zoological Paradoxes Part 4 Herdman, W. A. — Biological Results of Cruise of the ‘ Argo * „ Haddon’s (A. 0.) Collections in Torres Straits ... Part 5 Lankester, E. Ray — Animal Chlorophyll Part 6 Dixon, G. Y., & A. F. — Marine Invertebrate Fauna near Dublin . . . . „ Biedermann, W. — Origin and Mode of Termination uf Nerves in Ganglia of Invertebrata „ Whitman, C. O. — Spermatophores as a Means of Hypodermic Impregnation ,, Mollusca. Roebuck, W. D. — Census of Scottish land and Freshwater Mollusca .. .. Part 3 Thiele, J. — Phylogenetic Affinities of Mollusca Part G Johnston, R. M. — Tasmanian Mollusca „ a. Cephalopoda. Appellof, A. — Notes on Cephalopods Part 1 Joubin, L. — Development of Chromatophores of Octopod Cephalopoda .. .. Part 2 R a witz, B. — Changes in the Retinal Pigment of Cephalopods Part 5 B. Pteropoda. Knipowitsch, N. — Development of Clione limacina Part 4 y. Gastropoda. Garstang, W. — List of Opisthobranchiate Mollusca of Plymouth Part 1 Boutan, L. — Nervous System of Parmophorus australis „ Bouvier, E. L. — Nervous System of Cyprsea „ Pruvot, G. — Development of a Solenogaster „ Henchman, A. P. — Origin of Central Nervous System in Umax maximus . . Part 2 Grobben, C. — Pericardial Gland of Gastropoda „ Willem, Y. — Vision of Pulmonate Gastropods „ Bouvier, E. L. — Anatomy of 1 Hirondelle * Gastropods Part 3 Erlanger, R. y. — Development of Paludina vivipara „ Fischer, H. — Anatomy of Corambe testudinaria „ Chatin, J. — Hepatic Epithelium of Testacella „ Plate, L. — Heart of Dentalium „ Conkton, E. G. — Embryology of Crepidula and Urosalpinx Part 4 Willem, Y. — Eyes of Pulmonata Basommatophora „ Plate, L. — Anatomy of Daudebardia and Testacella Part 5 Cockerell, T. D. A. — Geographical Distribution of Slugs - „ Boutan, L. — Larval form of Parmophorus „ Schmidt, F. — Development of Central Nervous System of Pulmonata . . . . Part 6 Moynier de Villepoix — Growth of Shell of Helix aspersa F11AN901S, Ph. — Habits of a Murex Erlanger, R. v. — Development of Paludina Simroth, H. — The Genus Atopos Fischer, II. — Development of Liver of Nudibranchs Blumrich, J. — Integument of Chiton PAGE 327 327 328 453 454 581 717 718 718 719 328 721 722 25 175 581 454 26 26 27 27 176 176 177 329 329 330 330 330 454 455 582 582 582 722 723 723 724 724 725 725 CONTENTS. XI 5. Lamelliforanchiata. Pelseneer, P. — Primitive Structure of Kidney of Lamellibranchs . . . . Part 1 Schulze, F. E. — Crystalline Style Part 2 Letellier, A. — Renal Function of Acephalous Mollusca „ Pelseneer, P. — Hermaphrodite Lamellibranchs „ „ „ Otocysts of Nuculidx „ Griesbach, H. — Blood of Lamellibranchs Part 3 Norman, A. M. — Lepton squamosum ,, Voeltzkow, A. — Entovalva mirabilis Latter, O. H. — Anodon and Unio Part 4 Pelseneer, P. — Lamellibranchiata Part 5 Grobben, C. — The Bulbus Arteriosus and Aortic Valves of Lamellibranchs „ Blochmann, F. — The Free-Swimming Larva of Dreissena Part 6 Francois, P. — Circulation in Area „ Molluscoida. a. Tunicata. Morgan, T. H. — Origin of Test-cells of Ascidians Part 1 Salensky, W. — Embryonic Development of Pyrosoma Part 2 Lee, A. B. — Sense-organ of Salpa „ Pizon, A. — Blastogenesis of Astellium spongiforme Part 3 Giard, A. — Budding of Larva of Astellium spongiforme and Pcecilogony in Compound Ascidians „ Davidoff, M. y. — Development of Distaplia magnilarva „ Herdman, W. A. — Ecteinascidia and other Clavelinidas Part 4 Garstang, W. — Tunicata of Plymouth „ Herdman, W. A. — Classification of the Tunicata Part 5 „ „ Tunicata Part 6 Garstang, W. — New and Primitive Type of Compound Ascidian „ j8. Bryozoa. Prouho, H. — Cyclatella annelidicola Part 1 Davenport, C. B. — Cristatella Part 2 Harher, S. F. — British Species of Crisia Part 3 Hincks, T. — Marine Polyzoa „ Davenport, C. B. — Budding in Bryozoa Part 4 Harmer, S. F. — Regeneration of Lost Parts in Bryozoa „ Origin of Embryos in Ovicells of Cyclostomatous Polyzoa Oka, A. — Freshwater Polyzoa n Prouho, H. — Loxosoma annelidicola Part 5 Waters, A. W. — Characters of Melicertitidse and other Fossil Bryozoa .. „ Hincks, T. — Marine Polyzoa Braem, F. — Freshwater Polyzoa Part 6 Prouho, H. — Free Development in Ectoproctous Bryozoa „ y. Brachiopoda. Beecher, C. E. — Development of Brachiopoda Part 3 Francois, P. — Anatomy of Lingula Part 6 PAGE 28 177 178 178 178 331 331 332 455 582 584 726 726 29 178 179 332 332 333 456 456 585 726 727 29 179 335 336 456 457 457 457 585 586 586 727 728 336 728 Xll CONTENTS. Arthropoda. Fernald, H. T. — Relationships of Arthropods Part 1 Demoor, J. — Experimental Researches on Locomotion of Arthropods .. . . „ Patten, W — Is the Ommatidium a Hair-bearing Sense-bud ? „ Butschli, O., & W. Schewiakoff — Striated Muscles of Arthropoda.. .. Part 3 Jawohowski, A. — Extremities of Embryo of Arachnids and Insects .. .. Part 4 Schneider, A. — Circulatory and Respiratory Organs of some Arthropods .. Part 5 a. Insecta. Lameere, A. — Metamerism of Insect’s Body Part 1 Ochler, A. — Hooked Joint of Insects „ Bkhr, H. H. — Live Oak Caterpillar „ Pero, P. — Adhesive Organs on the Tarsal Joints of Coleoptera . . . . . . „ Cuenot, L. — Blood of Meloe and Function of Cantharidine in Biology of Vesicating Coleoptera .. .. „ Saunders, E. — Tongues of British Hymenoptera Anthophila „ Eckstein, K. — Life-history of Lyda „ W EiNLAND, E. — Halteres of Diptera . . „ Thomas, F., & E. H. Rubs a amen — A new Cecidomyia „ Brauer, E. — Host of Hypoderma lineata „ Sharp, D. — Terminal Segment of Male Hemiptera „ Sabatier, A. — Spermatogenesis in Locustidae „ Urech, E. — Ontogeny of Insects Part 2 Chobaut, A. — Life-history of Emenadia ,, Wasmann, E. — Function of the Antennse in Myrmedonia ,, Ballowitz, E. — The Spermatozoa of Coleoptera „ W asmann, E. — l’arthenogenesis of Ants induced by heightened temperature „ ,, ,, Can Ants hear ? „ Ritter, R. — Development of Chironomus ,, Gehcchten, A. v. — Histology of Gut in Larva of ffPtychoptera contaminata „ ,, „ Mechanism of Secretion in Larva of Ptychoptera con- taminata „ Vosseler, J. — Odoriferous Glands of Earwigs „ Lewis, R. T. — Stridulating Organ of Cystoccelia immaculata „ Levi-Morenos, D. — Food of the Larvae of Insects Part 3 Haase, E. — Odoriferous Organs of Lepidoptera ,, ,, „ Development of Nervures of Wings of Butterflies ,, Merrifield, F. — Effects of different Temperatures on Pupae of Lepidoptera „ Stainton, H. T. — Larvae of British Butterflies and Moths „ Blanchard, R. — Mistake of a Butterfly „ Beyer, O. W. — The Stinging Apparatus in Formica „ Bcgnion, E. — Structure and Life-history of Encyrtus fuscicollis .. .. „ Cuenot, L. — The Blood of Meloe and the Use of Cantharidine „ Dreyfus, L. — Moulting in Rhynchota „ Leon, N. — Hemidiptera Haeckelii „ Klapalek, F. — Metamorphoses of Oxyethira „ Cholodkovsky, N. — Central Nervous System of Blatta germanica .. .. „ Uzel, J. — Thysanura of Bohemia „ Coste, F. H. Perry — Chemistry of Insect Colours Part 4 Henking, H. — Early Stages of Development in Eggs of Insects Packard, A. S. — Insects injurious to Forest and Shade Trees „ PAGE 29 31 32 336 458 586 33 33 33 34 34 34 34 35 35 35 35 36 180 181 181 181 182 182 183 183 183 184 184 337 337 338 338 339 339 339 339 340 340 340 340 341 341 458 461 461 CONTENTS. Xlll TAGE Cobb, N. A., & A. S. Olliff — Insect-larva eating Bust on Wheat and Flax Tart 4 4G1 Bataillon, E. — Bole of Nucleus in Formation of Muscular Bcticulum in Larva of Phrygane „ 46 1 Knatz, L. — Absence of Wings in the Females of many Lepidoptera .. .. „ 462 Friese, H. — Natural History of Solitary Bees „ 462 Schafer, E. A. — Minute Structure of Muscle-columns in Wing-muscles of Insects Part 5 587 Graber, Y. — Origin of the Blood and Fatty-tissue in Insects Leydig, F. — Signs of Copulation in Insects Jackson, W. H. — Morphology of Lepidoptera Poulton, E. B. — Morphology of Lepidopterous Pupa .. Packard, A. S. — Phytogeny of Lepidopterous Larvae .. Ivecker, P. — Sound-Organs of Dytiscidae Graber, y. — Embryology of Insects „ „ Abdominal Appendages of Insect Embryos Poulton, E. B. — Protective Mimicry in Insects 11 91 11 11 Part 6 11 11 587 588 588 588 589 589 729 730 730 13. Myriopoda. Dad ay de Dees, E. — Hungarian Myriopoda Part 2 184 Plateau, F. — Marine Myriopoda and Beeistance of Air-breathing Arthro- pods to Immersion „ 184 Herbst, C. — Anatomy of Scutigera Part 4 463 Willem, V.- ^-Ocelli of Lithobius Part 5 590 7 . Prototraclieata. Dendy, A. — A New Species of Peripatus from Victoria Part 1 36 Fletcher, J. J. — Peripatus Leuckarti Part 3 341 8. Araclinida. Viallanes, H. — Structure of Nerve-centres of Limulus Part 1 36 Topsent & Trouessart — New Genus of Leaping Acari Part 2 185 Sars, G. O. — Pycnogonidea of Norwegian North Sea Expedition „ 185 Morgan, T. H'. — Embryology and Phytogeny of Pycnogonids Part 3 341 Kishinouye, Kamakichi — Development of Araneina Part 4 463 Bigula, A. — Mid-gut of Galeodidae M 463 McCook’s (H. C.) American Spiders 464 Karpelles, L. — External Characters of Mites 465 Sicher, E. — Embryology of Mites „ 466 Packard, A. S. — Brain of Limulus Polyphemus „ 466 Canestrini, G. — Classification of Mites Part 5 590 Sturany, R. — Coxal Glands of Arachnida n 591 Wakburton, C. — Oviposition and Cocoon-weaving of Agelena labyrinthica .. Part 6 731 Koenike, F. — Copulation of Water-mites „ 731 Batelli, A. — Anatomical and Physiological Notes on Ixodidee ,, 731 Kramer, P. — Post-embryonic Development of Acarida „ 732 Bertkau, Ph. — A Hermaphrodite Spider 732 Kishinouyo, K. — Development of Limulus longispinis n 732 e. Crustacea. Cattaneo, G. — Amoeboid Cells in Crab’s Blood Part 1 37 Marchal, P. — Excretory Apparatus of Palinurus , Gebia, and Crangon .. „ 37 XIV CONTENTS. Weldon, W. F. K. — Palsemonctes varians Wzesniowski, A. — Three Subterranean Gammaridse Canu, E. — Sexual Dimorphism of Copepoda Ascidiicola Eichard, J. — Test-gland of Freshwater Copepoda Solger, B. — Polar Bodies of Balanus Parker, G. H. — Eyes in Blind Crayfishes Hansen, H. T. — Cirolanidx and other Isopods Leichmann, G. — Oviposition and Fertilization in Asellus aquations „ „ Care of Young in Isopoda Bonnier, J. — Dimorphism of male Amphipoda Hacker, Y. — Maturation of the Ova of Cyclops Wiedersheim, E. — Movements in the Brain of Leptodora Bernard, H. — Hermaphroditism of Apodidae Canu, E. — Development of Ascidicolous Copepoda Knipowitsch, N. — Dendrogaster , a new form of Ascothoracida . . Thompson, I. C. — Monstrilla and the Cymbasomatidse Norman, A. M. — Bathynectes, a British Genus Nusbaum, J. — Embryology of Isopoda Ishikawa, C. — Formation of Eggs in Testis of Gebia major Claus, C. — Mediterranean and Atlantic Halocy prides Eichard, J. — Nervous System of Diaptomus Moniez, E. — Males of Freshwater Ostracoda Bouyier, E. L. — Arterial System of Crustacea Weldon, W. F. E. — Renal Organs of Decapod Crustacea Canu, G. — Female Reproductive Organs of Decapoda .. Vialanes, H. — Compound Eye of Macrura Herrick, F. H. — Development of American Lobster Lebedinsky, J. — Development of Daphnia from the Summer-egg Szczawinska, W. — Eyes of Crustacea Boule, L. — Development of Mesoderm of Crustacea Marchal, P. — Renal Secretion in Crustacea Nusbaum, J. — Morphology of Isopod Feet Stebbing, T. E. E. — JJrothoe and Urothoides „ „ New British Amphipods Hesse, E. — New and Rare French Crustacea Claus, C. — Goniopelte gracilis — a new Copepod Giesbrecht, W. — New Pelagic Copepoda Parker, G. H. — Compound Eyes of Crustacea Bath, O. yom — Dermal Sense-organs of Crustacea Demoor, J. — Motor Manifestations of Crustacea Cano, G. — Post-embryonic Development of Gonoplacidas Grobben, C. — Antennary Gland of Lucifer Reynaudii Schneider, A. — Arterial System of Isopods Boule, L. — Development of Germinal Layers of Isopoda Leichmann, G. — Reproduction of Isopoda Giesbrecht, W. — Secondary Sexual Characters in Copepods „ „ Distribution of Copepods Edwards, C. L. — New Copepoda Herdman, W. A. — Copepoda as Food Beneden, P. J. Van — Two new Lernxopoda Part 1 11 11 Part 2 11 11 11 Part 3 ii Part 4 ii ii ii u Part 5 11 11 11 11 11 11 Part 6 11 11 11 11 11 11 11 37 37 38 38 38 186 186 187 187 187 188 188 188 188 189 189 342 343 344 344 345 346 466 467 467 468 468 469 591 592 593 593 594 594 594 594 594 733 734 735 735 735 736 736 737 737 737 737 738 738 CONTENTS. XV Vermes. a. Annelida; PAGE Jourdan, E. — Epithelial Fibrillar Tissue of Annelids Part 1 39 Joyeux-Laffuie, J.— Chsetopterus „ 39 Apstein, C. — A new Alciopid „ 39 Millson, A. — The Work of Earthworms on the African Coast „ 40 Benham, W. B. — Tr ig aster and Benhamia .. „ 40 Beddard, F. E. — Heliodrilus .. ,, 41 Bergh, R. S. — Development of Leeches „ 41 Forbes, S. A. — American Terrestrial Leech „ 42 Andrews, E. A. — Anatomy of Sipunculus Gouldi „ 42 Wilson, E. B. — Origin of Me soblast- Bands in Annelids Part 2 190 Bergh, R. S. — Development of the Earthworm .. „ 191 Cerfontaine, P. — Cutaneous and Muscular Systems of Earthworm .. .. „ 191 Bourne, A. G. — Megascolex cseruleus . . „ 192 Horst, R. — New Genus of Earthworms „ 193 Beddard, F. E. — Structure of the Oligochxta „ 194 „ „ Homology between Genital Ducts and Nephridia in Oligo- chseta „ 194 Malaquin, A. — Reproduction of Autolytese ,, 195 Beddard, F. E. — Classification and Distribution of Earthworms Part 3 346 „ ,, Structure of New Earthworms „ 347 „ „ Structure of Deodrilus and Anal Nephridia in Acantho- drilus „ 347 „ „ Aquatic Earthworms „ 348 Service, R. — Perichseta indica „ 348 Vejdovsky, F. — Development of Vascular System in Annelids ,, 348 Shipley, A. E. — Phymosoma „ 348 Jourdan, E. — Innervation of Proboscis of Glycera Part 4 469 Benham, W. B. — Nephridium of Lumbricus and its Blood-supply . . . . „ 470 Randolph, H. — Regeneration of Tail in Lumbricus ,, 470 Beddard, F. E. — New Earthworm „ 471 „ „ Libyodrilus „ 471 Burger, O. — Embryology of Nephelis . .. „ 471 Malaquin, A. — Homology of Pedal and Cephalic Appendages in Annelids . . Part 5 595 „ „ Development and Morphology of Parapodia in Syllidinse, . . „ 595 Andrews, E. A. — Reproductive Organs of Diopatra „ 595 Michaelsen, W. — Earthworms of Berlin Museum. „ 596 Beddard, F. E. — New Form of Excretory Organ in an Oligochsetous Annelid „ 596 Bourne, A. G. — Naidiform Oligochxta „ 596 Rohde, E. — Histology of Nervous System of Hirudinea ,, 597 Ward, II. B. — Anatomy and Histology of Sipunculus nudus „ 598 Andrews, E. A. — Eyes of Polychseta Part 6 738 Treadwell, A. L. — Anatomy and Histology of Serpula dianthus .. .. ,, 739 Watson, A. T. — Protective Device of an Annelid ,, 739 Andrews, E. A. — Distribution of Mag elona .. .. „ 740 Whitman, C. O. — Clepsine plana ^ „ 740 Bolsius, II. — Further Researches on Segmental Organs of Hirudinea .. .. ,, 740 XVI CONTENTS. fr. Nemathelminthes. Mueller, A. — Nematodes of Mammalian Lungs and Lung Disease Linstow, O. v. — Allantonema and Diplogaster Bancroft, T. L. — Filariae of Birds Moniez, R. — Atlantonema rigidum Camerano, L. — • Development of Gordius Kaiser, J. — Histology of Echinorhynchus Linstow, O. y. — Gordius tolosanus and Mermis Cobb, N. A. — Arabian Nematodes Braun, M. — Echinorhynchus polymorphus and filicollis Burger, O. — Nectonema agile Cobb, N. A. — Anticoma Chatin, J. — Stylet of Heterodera Schachti Graff, L. — Organization of Accelous Turbellaria Hamann, O. — Structure of Nemathelminthes „ „ Monograph on Acanthocephala Kaiser, J. — Structure and Development of Echinorhynchus Stiles, C. W. — Notes on Parasites Part 1 PAGE 43 55 43 Part 2 195 5» 196 „ 196 55 196 Part 3 349 55 349 55 349 472 55 472 Part 5 598 55 599 Part 6 741 55 741 ♦ 5 742 742 y. Platyhelminth.es. Graff, L. y. — Enantia spinifera Railliet, A., & R. Blanchard— -Mode of Feeding in Flukes „ „ Nature of Monostoma leporis Monticelli, F. S. — Distribution of Gyrocotyle „ „ Ova and Embryos of Temnocephala chilensis Stedman, J. M. — Anatomy of Distomum fabaceum Moniez, R. — External Differences in Species of Nematobothrium Mrazek, A. — Cysticercoids of Freshwater Crustacea Erlanger, R. y. — Generative Apparatus of Taenia Echinococcus Linstow, O. v. — Taeniae of Birds and others Railliet, A. — Parasitic Origin of Pernicious Anaemia Bohmig, L. — Rhabdoccele Turbellaria Joubin, L. — Turbellaria of the Coasts of France Wagner, F. von — Asexual Reproduction of Microstoma Braun, M. — Helminthological Studies Parona, C., & A. Perugia — The Genus Vallisia Pintner, T. — Morphology of Cestoda Gote, S. — Connecting Canal between Oviduct and Intestine in Monogenetic Trematodes Br Andes, G. — The Holostomidae Blanchard, R. — Anomaly of Genital Organs of Taenia saginata Goti, Seitaro — Diplozoon nipponicum Woodworth, W. M. — Structure of Phagocata gracilis Harmer, S. F. — Rhynchodesmus terrestris Dendy, A. — Victorian Land Planarians Saint-Remy, G. — Genital Organs of Tristomidae Bell, F. Jeffrey— Tristomum histiophori Haswell, W. A. — Remarkable Flat-worm parasitic in Golden Frog .. Lominsky — Symbiosis of Echinococcus and Coccidia Saint-Remy, G. — Nervous System of Monocotylidea Blanchard, R. — Hymenolepis ^ Part 1 43 55 44 55 44 „ 44 55 44 55 45 55 45 55 45 55 46 47 55 47 Part 2 196 55 198 55 198 55 199 55 199 - 199 Part 3 350 55 350 55 351 Part 4 472 55 473 55 473 55 474 55 474 55 475 55 475 ,, 475 Part 5 600 n 600 CONTENTS. XVII Sharp, B. — Large Land Planarian Wagner, F. v. — The Papillae of Microstoma Monticelli, F. S. — The Genus Apoblema Braun, M. — Free-swimming Sporocysts Linstow, v. — Structure and Development of Taenia longicollis Mrazek, A. — Development of some Taeniae of Birds Rossiter, T. B. — Taenia coronula Guillebeau, A. — Echinococcus multilocularis in the Cow „ „ Cysticercus of Taenia saginata in the Cow PAGE Part G 742 99 >9 9> 99 9» 99 742 742 743 743 744 745 745 745 5. Incertae Sedis. Schimkewitsch, W. — Morphological Significance of Organic Systems of Enteropneusta Maupas — Fecundation of Hydatina senta Imhof, O. E. — Distribution of Pedalion mirum Kellicott, D. S. — New American Rotifer Dad ay, E. v. — Heterogenesis in Rotifers Thorpe, V. G. — List of Queensland Rotifera Rousselet, 0. — Vibratile Tags of Asplanchna amphora Western, G. — Notes on Rotifers .. Rousselet, C. — Dinops longipes Lang, A. — Organization of Cephalodiscus dodecalophus Cori, C. J. — Anatomy and Histology of Phoronis Petr, F. — Bohemian Rotifera Wierzejski, A. — Galician Rotifera Morgan, T. H. — Anatomy and Transformation of Tornaria , Masius, J. — Contribution to the Study of Rotifers Vallentin, R. — Anatomy of Rotifers Thompson, P. G. — Dasydytes bisetosum Frenzel, J. — A Multicellular , Infusorium-like Animal Cobelli, R. — Desiccation of Rotifers Maupas — Determination of Sexes of Hydatina senta Bryce, D. — Distyla ; New Rotifers Part 1 99 99 99 47 48 49 49 Part 2 200 „ 200 „ 201 „ 201 „ 201 „ 201 „ 201 Part 3 351 „ 351 Part 4 475 Part 5 600 99 99 99 601 602 602 Part 6 745 99 99 745 745 Echinodermata. Cuenot, L. — Enteroccelic Nervous System of Echinoderms Part 1 49 Ives, J. E. — Echinodermata of Yucatan and Vera Cruz „ 50 Carpenter, P. H. — Crinoids of Port Phillip ,, 51 Semon, R. — Morphology of Bilateral Ciliated Bands of Echinoderm Larvae Part 2 202 Agassiz, A. — Calamocrinus Diomedae „ 202 Ludwig, H. — Echinoderms of Ceylon Part 3 351 Wachsmuth, C., & F. Springer — Perisomatic Plates of Crinoids . . .. „ 352 Russo, A. — Ovary of Ophiurids „ 352 Hoyle, W. E. — Revised List of British Echinoidea „ 352 Ludwig, H., & P. Bartels — Anatomy of Synaptidae „ 352 Chadwick, H. C. — Fission of Cucumaria planci „ 353 Field, G. W. — Embryology of Asterias vulgaris Part 4 476 Brooks, W, K. — Early Stages of Echinoderms „ 477 Perrier, E. — Starfishes collected by the 1 Hirondelle ’ „ 477 Ludwig, H. — Classification of Holothurians 477 Hartlaub, C. — Comatulids of Indian Archipelago „ 479 1891. b XV111 CONTENTS. PAGE Bell, F. Jeffrey — British Species of Asterias Part 4 479 „ „ Classification of Echinodermata Part 5 602 Sladen, W. Percy — Echinodermata from South-west Ireland „ 604 Ludwig, H. — Development of Holothurians „ 604 Bell, F. Jeffrey — Bathybiaster vexillifer „ 606 Cuenot, L. — Morphology of Echinoderms Part 6 746 Ludwig, H. — Ludwig's Echinodermata „ 748 Janet, C., & L. Cuenot — Apical System of Echinoids „ 748 Coelenterata. Agassiz, A. — Rate of Growth of Corals Bassett-Smith, P. W. — Corals of Tizard and Macclesfield Banks Hickson, S. J. — Alcyonaria and Zoantharia from Port Phillip Koch, G. y. — Invagination of Tentacles in Rhizoxenia rosea and Asteroides calycularis „ „ Terminal Polyp and Zooid in Pennatula and Pteroeides M‘Murrich, J. P. — Structure of Cerianthus americanus Wagner, J. — Organization of Monobrachium par asiticum Bourne, G. C. — Hydroids of Plymouth Claus, C. — Scyphostoma of Cotylorhiza} Aurelia , and Chrysaora Weismann, A. — Hydra turned inside out Blanco, L., & P. Mayer — Spongicola and Nausithoe Cerfontaine, P. — Organization and Development of Anthozoa Koch, G. v. — Alcyonacea of Bay of Naples Studer, T. — Fissiparity in Alcyonaria Beneden, E. van. — Arachnactis and Morphology of Cerianthidse Carlgren, O. — Protanthea — a new Actinian „ „ Bolocera Koch, G. y. — Relation of Septa of Parent to those of Bud in Blastotrochus Faurot, L. — Cerianthus membranaceus Bell, F. Jeffrey — Antipatharia Hickson, S. J. — Ampullae of Millepora Murrayi „ „ Male Gonangia of Distichopora and Allopora Brooks, W. K., & E. G. Conklin — Structure of Gonophores Sloan, A. D. — Halistemma in British Waters M‘Murrich, J. Playfair — Development of Cyanea arctica Bigelow, R. P. — Physiology of ‘ Portuguese Man-of-War * Spencer, W. Baldwin — New Family of Hydroida Nussbauh, M. — Trembley's Experiments with Hydra M‘Murrich, J. Playfair — Phytogeny of Actinozoa Heider, A. R. V. — Coral-Studies Hickson, S. J. — Medusae of Millepora Murrayi and Gonophores of Allopora and Distichopora Maas, O. — Craspedota of the Plankton Expedition Brauer, A. — Development of Hydra Schneider, K. C. — Histological Observations on Coelenterata Cerfontaine, P. — Organization of Anthozoa Lacaze-Duthiers, H. de — Kophobelemnon at Banyuls Studer, T. — New Alcyonarian .. Kennel, J. v. — A Freshwater Medusa Schlater, G. — Sensory Papillae of Haliclystus auricula var Wilson, E. B. — Heliotropism of Hydra Part 1 55 55 55 55 55 55 Part 2 » Part 3 » » V Part 4 55 55 55 55 55 55 55 55 Part 5 55 55 5» Part 6 55 55 55 55 55 51 51 51 51 52 52 52 53 203 203 204 353 353 354 354 479 479 480 480 480 480 481 481 481 481 482 482 483 606 608 608 609 609 748 749 750 750 750 750 750 CONTENTS. XIX Porifera. Chatin, J. — Nucleus of Sponges Dendy, A. — Comparative Anatomy of Sponges „ „ Victorian Sponges „ „ Synute pulchella Lendenfeld, R. V. — System of Calcareous Sponges Keller, C. — Sponge-Fauna of the Red Sea Lendenfeld, R. v. — Classification of Sponges Delage, Y. — Development of Spongilla fluviatilis Protozoa. Verworn, M. — Psycho-physiological Studies on Protists Eismond, J. — Mechanism of Sucking in Suctoria Rousselet, C. — Amphileptus fiagellatus Cattaneo, G. — The Genus Conchophthirus Calvin, S. — Gigantic Specimens of Actinosphserium Thelohan, P. — Structure and Development of Spores of Myxosporidia Muller, E. — Cercomonas intestinalis Laveran, A. — Hxmatozoon of Malaria and its Evolution Danilewski, B. — Phagocytosis in Frogs and Birds Schuberg, A. — Stentor caeruleus Verworn, M. — The Life of Difflugia Steinhaus, J. — Cytophagus Tritonis Wright, J. — Foraminifera collected off the South-west of Ireland Fabre-Domergue — Notes on Ciliated Infusorians Henneguy, L. — Fabrea salina Plessis, G. du — New Pelagic Zoothamnium Howchin, W. — Estuarine Foraminifera of Port Adelaide River .. Thelohan, P. — New Sporozoa Garbini, A. — Sarcosporidia Wolters, M. — Conjugation and Spore-forming in Gregarines S jobbing, Nils — Parasitic Protozoid Organism in Cancer Schutz — Protozoan- and Coccidium-like Micro-organisms in Cancer-cells Danilewski, B. — Myoparasites of Amphibia and Reptilia Dantec, Le — Intracellular Digestion in Protozoa Ischikawa, C. — Conjugation in Noctiluca Pfeiffer, L. — Pathogenic Protozoa Borgert, A. — Dictyochida Bourne, A. G. — Pelomyxa viridis Burgess, E. W. — Foraminifera of Hammerfest Mingazzini, P. — New Monocystidea Gregory, J. W. — Tudor Specimen of Eozoon Balbiani, E. G. — Successive Regeneration of Peristome in Stentor Certes, A. — Two new Infusoria Penard, E. — Rhizopoda of the Lake of Geneva Rhumbler, L. — Origin and Growth of the Shell in Freshwater Rhizopods Penard, E. — Freshwater Rhizopods Simmons, W. J. — Biomyxa vagans Certes, A. — Trypanosoma Balbianii Schilling, A. J. — Freshwater Peridinese Labre, A. — Hsematozoa of the Frog Part 1 54 Part 2 204 Part 5 010 59 611 „ 611 59 611 Part 6 751 ” 751 Part 1 54 55 55 55 55 59 55 55 55 55 „ 56 56 56 Part 2 205 59 205 59 206 206 Part 3 355 99 355 99 356 55 356 95 356 „ 356 99 357 99 357 55 358 99 358 Part 4 483 59 484 99 484 Part 5 611 59 612 59 613 55 613 99 613 Part 6 751 59 752 59 752 5? 752 95 753 95 753 „ 753 99 753 99 754 b 2 XX CONTENTS. Vincent — Presence of bodies resembling Psorosperms in Squamous Epithelioma Danilewsky, B. — Polymitus malarise Antolisei & Angelini — Biological Cycle of Hxmatozoon falciforme . . Gbassi, B., & R. Feletti — Malaria- Parasites in Birds Massart, J. — Researches on Low Organisms Schewiakoff, W. — Zoochlorellse PAGE Part 6 » »> JJ 754 754 755 755 756 756 BOTANY. A. — General, including the Anatomy and Physiology of the Phanerogamia. a. Anatomy. Tschirch’s (A.) Text-book of Anatomy Part 2 Gravis, A. — Anatomy of Plants Part 4 Wiesner’s (J.) Anatomy and Organography (1) Cell-structure and Protoplasm. Pfeffer, W. — Absorption of Solid Substances by Protoplasm , and Formation of Vacuoles Part 1 Degagny, C. — Cell-division in Spirogyra „ Gregory, E. L. — Growth of the Cell-wall „ Wiesner, J. — Elementary Structures and Growth of the Vegetable Cell . . Part 2 Degagny, C. — Nuclear Origin of Protoplasm „ Kienitz-Gerloff, F. — Protoplasmic Connection between adjacent Cells .. Part 3 Klebs, G. — Formation of Vacuoles ,, Palla, E. — Formation of Cell-wall in Protoplasts not containing a Nucleus „ Degagny, C. — Antagonistic Molecular Forces in the Cell-nucleus „ Steinbrinck, C. — Hygroscopic Swelling and Shrinking of Vegetable Membranes Part 4 Gerassimoff, J. — Function of the Nucleus Part 5 Guignard, L., E. De Wildeman, & P. Van Tieghem — “ Attractive Spheres ” in Vegetable Cells ( Tinoleucites) „ Moore, S. Le M. — Nature of Callus „ Fayod, V. — Structure of Living Protoplasm Part 6 Acqua, C. — Structure and Growth of the Cell „ Wildeman, E. de — Influence of Temperature on Caryokinesis „ (2) Other Cell-contents (including- Secretions). Monteverde, N. A. — Calcium and Magnesium Oxalate in Plants .. .. Part 1 Macchiati, L. — Yellow and Red Colouring Matters of Leaves „ Ludwig, F. — Pigment of the Synchytrium-galls of Anemone nemorosa.. .. „ Borodin, J. — Dulcite in Plants „ Fraser, T. R. — Strophanthine „ Aubert, E. — Distribution of the Organic Acids in Succulent Plants .. .. Part 2 Daniel, L. — Tannin in the Compositse ,, Voigt, A. — Localization of the Essential Oil in the Tissue of the Onion .. „ Waage, T. — Occurrence and Function of Phloroglucin „ Bredow, H. — Structure and Formation of Chromatophores Part 3 Eberdt, O., & E. Belzung — Origin and Development of Starch-grain .. „ Zimmermann, A. — Protein-crystalloids in Cell-Nucleus of Flowering Plants „ Guignard, L. — Localization of the Active Principles of the Crucifer x . , . . „ 207 485 485 58 58 59 207 208 359 359 360 360 485 614 614 615 757 757 758 59 59 60 60 60 208 209 209 209 360 361 362 362 CONTENTS. XXI Mer, E. Distribution of Starch at different periods of the year in woody plants Buscalioni, L. — Structure of Starch-grains in Maize Hartley, W. N.— Spectrum of Chlorophyll Linossier, G. — Aspergillin — a Vegetable Haematin Belzung, E. — Aleurone-grains in Papilionacese Mann, G. — Chlorophyll Berthelot & G. Andre — Sulphur in Plants Kraus, G. — Calcium oxalate in the Bark of Trees Arcangeli, G. — Crypto-crystalline Calcium oxalate Monteverde, N. — Chlorophyll Palladin, W. — Green and Etiolated Leaves Lesage, P. — Quantity of Starch contained in the Radish Braemer, L. — Tannoids Arcangeli, G. — Crystals of Calcium oxalate PAGK Part 4 485 „ 486 „ 486 „ 486 Part 5 615 „ 616 „ 616 „ 616 „ 616 Part 6 758 „ 758 „ 759 „ 759 „ 759 (3) Structure of Tissues. Muller, C. — Collenchyme part j go Holfert, J. — Nutrient layer in the testa 61 Lignier, O. — Foliar Fibrovascidar System gl Ravaz, L. — Cuttings of the Vine 62 Radlkofer, L. — Cystoliths M 62 Schwendener, S. — Mestome-sheath of Grasses „ 62 Wilson, J. — Mucilage and other glands of the Plumbaginex „ 62 Garcin, A. G. — Structure of Apocynacex 63 Seligmann, J. — Campanulacex and Composite 63 Douliot, H. — Apical Tissue in the Stem of Phanerogams v .. Part 2 210 Potter, M. C. — Increase in thickness of the Stem of Cucurbitacex .. .. „ 210 Lamounette — Morphological Origin of the Internal Liber }J 210 Tubeuf, K. y. — Formation of Duramen }} 211' Kny, L. — Medullary Rays „ 211 Blass, J., & H. Lecomte — Function of the Sieve-portion of Vascular Bundles „ 211 Leger, L. J. — Laticiferous System of Fumariaceae „ 212 Schaar, F. — Reserve-receptacles in the Buds of the Ash „ 212 Henslo w, G. — Vascular System of Floral Organs . . Part 3 363 Tieghem, P. Van — Pericycle and Peridesm „ 363 Vries, H. de — Abnormal Formation of Secondary Tissues ,, 364 Rodham, 0. — Sieve-septum of Vessels „ 364 Trecul, A. — Order of appearance of the Vessels in the Flowers of Trago- pogon and Scorzonera ,, 364 Closed. — Independence of Fibro-vascular bundles in the appendicular organs „ 364 Russell, W. — Cortical Bundles in Genista „ 365 Dudley, P. H. — Elliptically wound Tracheids „ 365 Thouvenin, M. — Anatomy of Saxifragacex „ 365 Schumann, P. — Variations in the Anatomical Structure of the same Species Part 4 487 Schuppan, P. — Wood of Conifers „ 487 Kny, L. — Abnormal Structure of Annual Rings „ 487 Muller, C. — “ Sanio’s Bands ” in the Coniferae „ 488 Gibson — Suberin and Bark-cells „ 488 Seliwanow, T. — Reactions'of Lignin ,, 488 Devaux, H. — Hypertrophy of Lenticels „ 488 XXII CONTENTS. PAGE Lesage, P. — Development of the Root „ „ Differentiation of the Phloem in the Root Herail, J. — Medullary Phloem in the Root Bordet — Anatomical Researches on Carex Leonhard, M. — Structure of Apocynacese Lesage, P. — Differentiation of the Endoderm Van Tieghem, P. — Folded Tissue Baccarini, P., & P. Vuillemin — Secretory System of Papilionacex .. Zopf, W. — Alkaloid-receptacles of the Fumariacex Dehmel, M., & Thouvenin — Latex-receptacles Beauvisage, G. — Sieve-fascicles in the Secondary Xylem of Belladonna Van Tieghem, P. — Extra-phloem Sieve-tubes and Extra-xylem Vessels Freemont, A. — Extra-phloem Sieve-tubes in the Root of the (Enotherex Zimmermann, A., & C. Giesenhagen — Cystoliths of Ficus Pee-Laby, E. — Supporting -elements in the Leaf Berger, F. — Anatomy of Conifers Scott, D. H. — Anatomy of Ipomxa versicolor Gravis, A. — Anatomy and Physiology of the Conducting Tissues Scott, D. H., & G. Brebner — Internal Phloem in Dicotyledons Dangeard, P. A. — Equivalence of the Vascular Bundles in Vascular Plants Koch, L. — Structure and Growth of the Apex in Gymnosperms Jost, L. — Increase in Thickness of the Stem and Formation of Annual Rings Berckholtz, W. — Gunnera manicata Part 5 Part 4 489 „ 489 „ 489 „ 489 489 617 617 617 618 618 618 618 619 619 619 619 620 759 Part 6 760 760 760 761 761 (4) Structure of Org-ans. Stenzel, G. — Variations in the Flower of the Snowdrop Delpino, F. — Nectary-covers Stenzel, G. — Variations in the Structures of the Acorn Kerner v. Marilaun, A. — Buds of Sempervivum and Sedum Prunet, A. — Dormant Buds in Woody Dicotyledons Arcangeli, G. — Leaves of Nymphxacex Daguillon, A. — Leaves of Conifers Satjvageau, C. — Leaves of Marine Phanerogams Lanza, D, — Leaves of Aloinex Scherffel, A. — Filaments in Scales of Rhizome of Lathrxa squamaria Weiss, A. — Trichomes of Corokia budleoides Poulsen, V. A. — Bulbils of Malaxis Goebel, K. — Morphology of Utricularia Kadlkofer, L. — Structure of Sapindacex Masters, M. T. — Morphology of the Coniferx Delpino, F. — Theory of Pseudanthy Wettstein, B. yon — Staminodes of Parnassia Fischer, H. — Pollen-grains Russell, W. — Tendrils of the Passifloracex Schimper, A. F. W. — Protection of Foliage against Transpiration Russell, W. — Abnormal Leaves of Vicia sepium Lothelier, A. — Influence of Moisture of Air on Production of Spines Palla, E. — Aerial Roots of Orchidex Celakovsky, L. — Morphology and Phytogeny of Gymnosperms Karsten, G. — Structure of the Rhizophorex Schumann, K. — Order of Succession of the Parts of the Flower Saunders, E. R. — Septal Glands of Kniphofla Part 1 63 „ 63 „ 64 „ 64 » 6^ „ 64 „ 65 „ 65 „ 66 „ 66 „ 66 „ 66 „ 67 „ 67 Part 2 212 „ 213 „ 213 213 „ 213 „ 214 „ 214 „ 214 „ 215 3 365 365 366 366 Part CONTENTS. XX111 Gakcin, A. G. — Development of Fleshy Pericarps Meunier, L. — Integument of the Seed of Cyclospermx Weiss, A. — Stomates Sauvageau, C. — Rudimentary Stomates in Aquatic Plants Loew, E. — Metamorphosis of vegetative shoots in the Mistletoe Vuillemin, P. — Leaves of Lotus Duchartre, P. — Production of Bulbils in Lilium auratum Laurent, E. — Nodosities on the Roots of Leguminosx Koch, A. — Filaments in the Root-tubercles of Leguminosx Noll, F. — Influence of External Factors on Formation and Form of Organs Candolle, C. de — Epiphyllous Inflorescences Levi Morenos, D. — Variations in the Flower Foerste, A. F. — Formation of Flower-buds of Spring-blossoming Plants Duchartre, P. — Inferior Ovaries Halsted, B. D., & D. G. Fairchild — Influence of Moisture on Dehiscent Fruits Huth, E. — Geocar pous, Amphicarpous , and ffeterocarpous Fruits Devaux, H. — Porosity of the Fruit of Cucurbitacex .. .. Brandza, M. — Development of the Integument of the Seed .. D’Arbaumont, J. — Integuments of the Seed of Cruciferse Sauvageau, C. — Stem of Zostera ' Rosenplenter, B. — Spiral Phyllotaxis Weisse, A. — Leaf-spirals in the Conifer x Lothelier, A. — Influence of Light on the production of Spines Buchenau, F. — Bulbs and Tubers in the Juncacex Devaux, H. — Growth of Root-hairs Kuntze, G. — Anatomy of the Malvaceae Wiesner, J. — Changes in the Form of Plants produced by Moisture and Etiolation Karsten, G. — Mangrove-vegetation Pitzorno, M. — Stigmatic Disc of Vinca Palla, E. — Pollen of Strelitzia Korella, W. — Stomates in the Calyx Lubbock, Sir J. — Fruit and Seed of the Juglandeae „ „ Leaves of Viburnum „ „ Form and Function of Stipules Muller-Thurgau, H. — Pearl-like Glands of the Vine Klebabn, H. — Roots springing from Lenticels Prazmowski, A. — Root-nodules of the Pea Lamarliere, G. de — Structure of swollen Roots in certain Umbelliferae . . Chatin, A. — Comparative Anatomy of Plants Hildebrand, F. — Sudden Changes of Form Chamberlain, J. S. — Styles of Composite Clos, D. — Embryo of Trapa , Nelumbium , and of some Guttiferx Huth, E. — Fruits which expel their seeds with violence ( Schleuderfriichte ) . . Tanfani, E. — Fruit and Seed of Umbelliferae Heineck, O. — Pericarp of Composite Baroni, E. — Structure of the Seed of Euonymus Simek, F. — Structure of Cotyledons Sauvageau, C. — Stem of the Cymodoceae Krick, F. — Swellings in the Bark of the Copper-beech Schmidt, C. — Leaves of Xerophilous Liliiflorex Part 3 » 11 M 11 Part 4 11 11 11 11 11 11 11 11 11 11 11 11 Part 5 11 11 11 11 11 H Part 6 11 11 11 11 11 11 11 11 PAGR 366 367 367 367 367 368 368 368 368 490 490 490 490 491 491 491 491 491 492 492 493 493 493 493 493 494 620 620 621 621 621 621 622 622 622 922 623 623 761 762 762 763 763 763 764 764 764 764 764 765 XXIV CONTENTS. Klein, J. — Abnormal Leaves W a age, T. — Loots without a Boot-cap Atkinson, G. F. — Tubercles on the roots of Ceanothus PAGE Part 6 765 5? 5J 765 766 j8. Physiology. Hansen’s (E. C.) Vegetable Physiology Part 5 623 (1) Reproduction and Germination. Focke, W. — Hybridization and Crossing Warming, E — Fertilization of Caryophyllacex Arcangeli, G. — Fertilization of Aracex Halsted, B. D. — Artificial Germination of Milk-weed Pollen Leger, L. J. — Abnormal Germination of Acer platanoides Ascherson, P. — Dissemination of the Seeds of Harpagophyton Brandza, M. — Anatomical Characters of Hybrids Meehan, T. — Proterandry and Proterogyny Robertson, C. — Flowers and Insects Meehan, T. — Self-fertilized Flowers Lindman, 0. A. M. — Pollination of the Mistletoe Correns, C. — Pollination of Aristolochia , Salvia, and Calceolaria Knuth, P. P. — Pollination of Crarnbe maritima Focke, W. O. — Change in Colour of the Flower of the Horse-chestnut . . Dangeard, P. A. — Oospores formed by Union of Multinucleated Sexual Elements Green, J. R. — Germination of Seed of Castor-oil Plant Mattirolo, O., & L. Btjscalioni — Germination of Seeds of Papilionacex . . Fressanges — Germination of the Sugar-cane Devaux, H. — Temperature of Tubercles during Germination Rolfe, R. A. — Sexual Forms of Catasetum Clos, D. — Germination within the Pericarp in Cactacese Moebius, M. — Results of continual Non-sexual Propagation Hill, E. G. — Cross-fertilization and Self-fertilization Kornicke — Autogenetic and Heterogenetic Fertilization Beketow, A. — Proterandry in the Umbelliferx Bottini, A. — Reproduction of Hydromystria Vries, II. de — Duration of the Life of certain Seeds Morris, D. — ■ Germination of the Sugar-cane Bowers, H. — Germination of Hydrastis Canadensis Gcignard, L. — Sexual Nuclei in Plants Sokolowa, C. — Formation of Endosperm in the Embryo-sac of Gymnosperms Meehan, T. — Relations between Insects and Flowers Loew, E. — Fertilization of Papilionacex Kellgren, A. G. — Lepidopterophilous Flowers Bcrck, W. — Weismann’s Theory of Heredity Westermaier, M. — Function of the Antipodals Her ail, J. — Reproductive Organs of Phanerogams Burck, W. — Cleistogamic Flowers Rosen, F. — Importance of Heterogamy in the formation and maintenance of species • Overton, E. — Fertilization of Lilium Martagon Dodel, A. — Fertilization of Iris sibirica Loew, E., and others — Contrivances for Pollination Part 1 67 68 68 68 69 69 Part 2 215 V 215 215 216 216 216 217 217 M 217 217 218 218 218 Parts 369 „ 369 Part 4 494 „ 494 „ 494 „ 495 „ 495 „ 495 „ 495 „ 495 Part 5 623 „ 623 „ 624 „ 625 „ 625 Part 6 766 „ 766 766 767 767 767 768 768 CONTENTS, XXV Wilson, J. II. — Pollination and Hybridizing of Albuca.. Knuth, P. — Pollination of Orobanclxex Day, T. 0. — Influence of Temperature on Germinating Barley Hemsley, W. B. — Vitality of Seeds Gandoger, M. — Longevity of Bulbils Beck v. Mannagetta, G. R. — Parasitism of Orobanche Johow, F. — Phanerogamic Parasites Devaux, H. — Rooting of Bulbs and Geotropism Kreusler — Assimilation and Respiration Jumelle, H. — Assimilation by Red Leaves Bonnier, G. — Influence of high altitudes on Assimilation and Respiration Kruticki, P. — Permeability of Wood to Air Frank, B. — Assimilation of Nitrogen by Robinia Bokorny, T. — Conduction of Water Mischke, K. — Increase in thickness of the Conferee Koch, L. — Parasitism of Euphrasia Saposchnikoff, W. — Formation and Transport of Carbohydrates Frank, B., & R. Otto — Assimilation of Nitrogen by Plants Palladin, W. — Effect of Transpiration on Etiolated Plants Boehm, J. — Ascending and descending Current in Plants Devaux, H. — Internal Atmosphere of Tubers and Tuberous Roots Chatin, A. — Biology of Parasites Yochting, H. — Assimilation of Leaves Atwater, W. O., & 0. D. Woods — Absorption of Atmospheric Nitrogen by Plants Prunet, A. — Perforation of Potatoes by the Rhizome of Grasses Loew, O. — Physiological Function of Phosphoric Acid Lesage, P. — Influence of Salt on the Quantity of Starch contained in the Vegetative Organs Bokorny, T. — Transpiration-current Devaux, H. — Passive Circulation of Nitrogen in Plants Pfeffer, W. — Absorption and Elimination of Solid Substances by Cells Lamarlieiie, G. de — Assimilation in Umbelliferx Otto, R. — Assimilation of free atmospheric Nitrogen Schmidt, R. M. — Absorption and Metabolism of Fatti (3) Irritability. Leveille, H. — Action of Water on Sensitive Movements Paoletti, G. — Movements of the Leaves of Porlieria hygrometrica Ville, G. — Sensitiveness of Plants to certain Salts Hansgirg, A. — Sensitive Stamens and Stigmas , „ Nyctitropic Movements of Leaves „ „ Carpotropic Curvatures of Nutation Koch, A. — Influence of Gravitation on the Sleep-movements of Leaves Bastit, E. — Heliotropism aud Geotropism in Mosses Arcangeli, G. — Compass-plants Steinbrinck, C. — Anatomico-physical causes of Hygroscopic Movements Part 6 769 99 769 9 9 769 99 769 99 770 s). Part 1 69 99 69 99 70 99 70 99 71 99 71 99 71 19 71 Part 2 218 „ 218 99 219 Part 3 369 ?> 369 99 370 9» 370 99 370 99 371 99 371 Part 4 495 ?9 496 99 496 99 496 Part 5 625 99 625 99 625 99 626 Part 6 770 v 770 99 770 99 771 99 771 Part 1 71 99 71 Part 2 219 Part 3 371 99 372 99 372 99 373 99 373 Part 4 496 Part 6 771 XXVI CONTENTS. PAGE Macfarlane, J. M. — Irritability of the Leaves of Dionaea Part G 771 Halsted, B. D. — Heliotropic Sundew n 772 (4) Chemical Changes (including Respiration and Fermentation). Chrapowicki, W. — Formation of Albuminoids Fischer, A. — Physiology of Woody Plants Curtel, G. — Physiological Researches on the Floral Envelopes Kohl, F. G. — Formation of Calcium Oxalate Laurent, E. — Redaction of Nitrates to Nitrites by Plants Mori, A. — Influence of Anaesthetics on Respiration "Wortmann, J. — Presence of a Diastatic Enzyme in Plants Sigmund, W. — Oil-decomposing Ferment in Plants Golden, K. E. — Fermentation of Bread Kayser, E. — Fermentation of Cider Jumelle, H. — Influence of Anaesthetics on Assimilation and Transpiration.. Detmer, W. — Respiration of Plants Grehant & Quinquad — Respiration and Fermentation of Teast Beyerinck, M. W. — Lactase , a new Enzyme Frankland, P. F. & G. C. — Nitrifying Process and its Specific Ferment . . Stich, C. — Respiration of Plants Devaux, H. — Respiration in the interior of massive tissues Peyron, J. — Composition of the internal Atmosphere of Plants Monteverde, N. — Influence of Carbohydrates on Formation of Asparagin . . Lesage, P. — Influence of Saltness on the Formation of Starch in Vegetable Organs containing Chlorophyll Villiers, A. — Transformation of Starch into Dextrin by the Butyric Ferment Nickel, E. — Tannins and Trioxybenzols Suchsland, E. — Fermentation of Tobacco Loew, O. — Nitrification by a Schizomycete Purjewicz, K. — Influence of Light on Respiration Wehmer, C. — Formation and Decomposition of Oxalic Acid and its Function in the Metabolism of Fungi Linossier, G., & G. Roux — Alcoholic Fermentation and the Conversion of Alcohol into Aldehyde by the “ Champignon du Muguet ” __ Boutroux, L. — Fermentation of Bread Frankland, P. F., & others — Fermentations induced by the Pneumo- coccus of Friedlaender Vines, S. H. — Diastatic Ferment in Green Leaves Part 1 Part 2 72 219 * 220 „ 220 *» 220 „ 221 „ 221 „ 221 „ 221 „ 222 Part 3 373 „ 374 „ 374 „ 374 „ 374 497 497 497 497 Part 4 „ 498 „ 498 „ 498 Part 5 626 „ 626 Part 6 772 „ 772 . v 773 » 773 773 774 y. General. Koze, E. — Action of Solar Heat on the Floral Envelopes Fliche, L. — Biology of the Ericaceae Schumann, K. — Myrmecophilous Plants Dubois, R. — Digestive Properties of Nepenthes Lundstrom, A. N. — Absorption of Rain by Plants Kirchner, 0. — Diseases and Injuries of Plants Regel, R. — Influence of External Factors on the Odours of Flowers .. Ludwig, F. — Relationship between Plants and Snails Fruh, J. — Constitution and Formation of Peat Schumann, K. — African Myrmecophilous Plants Ettingshausen, C. v., & Krasan — Atavism of Plants Meehan, T. — Evolution of Parasitic Plants Leveille, H. — Exudation of Sap by Mangifera Part 1 72 * 72 ,, 73 Part 3 375 „ 375 „ 375 Part 4 498 „ 499 „ 499 Part 5 626 „ 626 Part 6 774 CONTENTS. XXVU B. — Cryptogamia. Cryptogamia Vascularia. Seward, A. 0. — Sphenophyllum and Asterophyllites Part 1 Wojinowic, W. P. — Selaginella lepidophylla Part 2 Kruch, O. — Vascular Bundles of Isoetes Bower, F. O. — Lycopodiacese Giesenhagen, C. — Hymenophyllaceae Tieghem, P. van — Stem of Ophioglossacese Farmer, J. B. — Structure of Isoetes Part 3 Tieghem, P. van — Stem of Equisetaceae „ Dangeard, P. — Tmesipteris Part 4 Campbell, D. H. — Archegone of Ferns „ Yelenoysky, J. — Rhizome of Ferns Campbell, D. H. — Apical Growth of Osmunda and Botrychium Poirault, G. — Structure of Ophioglossacese „ Newberry, J. S. — Sphenophyllum „ Bower, F. O. — Phylogeny of Ferns Part 5 Campbell, D. H. — Apical Growth of the Prothallium of Ferns „ „ „ Life-history of Isoetes Part 6 Poirault, G. — Sieve-tubes of Filicineae and Equisetineae „ Figdor, W. — Nectaries of Pteris aquilina „ Poirault, G. — Peculiarity in the Root of Ceratopteris thalictroides Hovel acque, M. — Structure of the Primary Fibro-vascular System in Lepidodendron selaginoides Muscineae. Philibert — Peristome Part 1 Nawaschin, S. — Microspores of Sphagnacese „ Goebel, K. — Javanese Hepaticx „ Vaizey, J. R. — Sporophyte of Splachnum Part 3 Limpricht, K. G. — Rabenhorst's Cryptogamic Flora of Germany (Mosses') . . „ Bastit, E. — Influence of the hygrometric state of the air on the position and function of the leaves of Mosses Part 4 Kruch, O. — Sexual Organs and Impregnation in Riella „ Jameson, H. G. — British Mosses Part 5 Mottier, D. M. — Apical Growth of Hepaticae „ Mitten, W. — New Genera of Mosses , Aulacomitrium and Willia Part 6 Cliaraceae. Overton, W. — Histology of Char ace ae . . . . Part 1 Zacharias, E. — Growth of the Cell-wall in Chara fcetida Part 4 Rabenhorst’s Kryptogamen-Flora v. Deutschland ( Cliaraceae ) Part 6 Algae. Kjellman, F. R. — Algae of Behring's Sea Part 1 Agardh, J. G. — Sargassum Bornet, E. — New Genus of Phaeosporeae Wildeman, E. de — Prasiola and Schizogonium Bohlin, K. — Myxochaete, a new Genus of Algae Cramer, C. — Neomeris and Bornetella . . Bosse, W. van — Phytophysa PAGE 73 222 222 223 223 224 376 376 499 500 500 500 500 500 627 627 774 775 775 776 776 73 73 73 377 377 501 501 627 627 776 74 501 776 74 75 75 75 75 75 76 XXYlll CONTENTS. Migula, W. — Gonium pectorale Maillard, G. — Fossil Algae Weber- Van Bosse, A., & M. Weber — Symbiosis of Algae and Animals .. Kjellman, F. R. — Fucoideae of Scandinavia Reinke, J. — Sphacelariacex Reinsch, P. F. — New Genera of Algae Haberlandt, G. — Conjugation of Spirogyra Wildeman, E. de — Trentepohlia „ „ Enteromorpha Klein, L. — Volvox and Eudorina Klebs, G. — Reproduction of Hydrodictyon Agardh, J. G. — New Genus of Siphonex Holmes, E. M., & E. A. L. Batters — British Marine Algae Bornemann, F. — Lemaneaceae Setchell, W. A. — Tuomeya fluviatilis Richards, H. M. — Structure of Zonaria Chmielevsky, V. — Chlorophyll-bands in the Zygote of Spirogyra Klebahn, H. — Germination of Closterium and Cosmarium Stockmayer, S., & F. Gay — Rhizoclonium Behrens, J. — Oogone and Oosphere of Vaucheria Artari, A. — Development of Hydrodictyon Harvey-Gibson, R. J. — Cystocarps and Antherids of Catenella Opuntia .. Barton, E. S. — Galls on a Sea-weed Debray, F. — Structure and Development of Chylocladiex West, W. — Conjugation of the Zygnemaceae Dangeard, P. A., & E. de Wildeman — Clamp-organs of the Conjugate .. Gay, F. — Mode of Attachment of Cladophora Hariot, P. — Pleiocarpous Species of Trentepohlia De-Toni’s ( J. B.) Sylloge Algarum Kohl, F. G., & B. M. Davis — Continuity of Protoplasm in Algae Harvey-Gibson, R. J. — Histology of Polysiphonia fastigiata „ „ Sporange of Rhodocorton Cramer, C. — Caloglossa Leprieurii Webber, H. J. — Antherids of Lomentaria Smith, A. L. — Cystocarp of Callophyllis Karsten, G. — New Freshwater Floridea Murray, G., & E. S. Barton — Chantransia, Lemanea, and Batracho- spermum De Toni, J. B. — Classification of Fucoideae Johnson, T. — Phaeosporeae „ „ Dictyotaceae Mann, G. — Spirogyra Borzi, A. — Ctenocladus „ „ Leptosira and Microthamnion Meyer, A. — Cell-sap of Valonia Goroschankin — Structure and Reproduction of Chlamydomonas Borzi, A. — Hariotina Oltmanns, F. — Influence of the Concentration of Sea-water on the Growth of Algae MObius, M. — Endophytic Algae Istvanpfi, J. — Meteor-paper ” Buffham, T. H. — Reproductive Organs of Florideae Part 1 11 Part 2 11 11 11 11 11 Part 3 11 11 11 I* 11 11 11 11 Part 4 11 11 11 11 11 Part 5 11 11 11 11 11 11 11 11 11 11 11 11 11 11 Part 6 11 11 PAGE 76 76 224 225 225 226 226 226 226 226 227 227 377 377 378 378 378 378 379 379 380 502 502 502 502 502 503 503 503 628 628 628 628 628 629 639 629 629 630 630 630 630 631 631 631 632 777 777 777 777 CONTENTS. XXIX PAGE Richards, H. M. — Chreocolax Part 6 778 Reinke, J. — Sphacelariacex „ 778 Murray, G. — Cladothele and Stictyosiplion „ 778 Wildeman, E. de — Gladophora .. „ 778 Hansgirg, A. — Hormidium , Schizogonium , and Hormiscia „ 778 •Barber, C. A., & W. T. Thiselton-Dyer — Pachytheca 779 Fungi. Bourquelot, E. — Carbohydrates in Fungi Rostrup, E. — New Ustilaginex Martelli, U. — Dissociation of a Lichen Jacquemin, G. — Bouquet of Fermented Liquors Barclay, A. — Indian Busts and Mildews Soppitt, H. T. — Puccinia digraphidis Atkinson, G. F. — New Ramularia on Cotton Ludwig, F. — TJredo notdbilis Hennings, P. — JEcidium Schweinfurthii Blanchard, R. — New Type of Dermatomycosis Fischer, E. — Phalloidex Karsten, P. A. — New Genera of Basidiomycetes Loew, O. — Behaviour of the lower Fungi towards inorganic nitrogen-compounds Bourquelot, E. — Trehalose in Fungi Wildeman, E. de — Saprolegniacese parasitic on Algae Lockwood, S. — Devcea, a new marine genus of Saprolegniacese Zukal, H. — Gymnoascaceae and Ascomycetes Prillieux, E. — Disease of the Beetroot Galloway, B. T. — Black-rot of Grapes . . . . Rostrup, E. — Fungi parasitic on Forest-trees Hesse, R. — Development of the Hypogaei Wainio, E. — Classification of Lichens Rommier, A. — Preparing Wine-Ferments Poirault, G. — TJredinese and their Hosts Barclay, A., & P. Dietel — Himalayan Uredineae Lagerheim, G. von — Uredo Vialae Barclay, A. — JEcidium esculentum Dangeard, P. A. — Histology of Fungi Dubois, R. — Action of Fungi on copper and bronze Russell, H. W. — Effect of corrosive sublimate on Fungi Mangin, L. — Structure of the Peronosporeae Rothert, Y. — Development of the Sporanges in the Saprolegniacese . . Zukal, H. — Thamnidium mucoroides Borzi, A. — Bargellinia , a new Genus of Ascomycetes Zukal, H. — Semi-lichens Bachmann, E. — Calcareous Lichens Hulth, J. M. — Reserve-Receptacles in Lichens Minks, A. — Myriangium Sadebeck, R. — Pathogenic Species of Taphrina Hansen, E. C. — Distribution of Saccharomyces apiculatus Barclay, A. — Life-history of Puccinia Geranii sylvatici Moeller, H. — Frankia subtilis Patouillard, N. — Podaxon „ „ Spores on the Surface of the Pileus of Poly porese .. Part 1 55 55 55 55 55 55 Part 2 55 55 55 55 55 55 55 Part 3 55 55 >5 55 55 55 77 77 77 77 78 78 78 78 78 78 78 79 227 228 228 228 228 229 229 229 230 230 230 231 231 231 232 380 381 381 381 382 382 382 382 383 383 383 383 383 384 384 384 384 XXX CONTENTS, Elfving, F. — Influence of Light on the Growth of Fungi Cooke, M. C. — Dispersion and Germination of the Spores of Fungi Bourquelot, E. — Carbohydrates in Fungi Dangeard, P. A. — Endotrophic Mycorhiza Wevre, A. de — Chxtostylum Lambotte, E. — Mycele and Protospores of Sphaerotheca Castagnei v. humilis and of Pleospora herbarum v. Galii aparinis Woronin, M. — “ Taumel-getreide ” Lagerheim, G. v. — Mush-fungus Vlala, P. — New Vine-disease Minks, A. — Atichia Cramer, C. — Chlorodictyon foliosum and Ramalina reticulata Willey, H. — Arthonia Atkinson, G. F. -Black-rust of Cotton Bressadola, I. — New Genus of Tubercularieae Roze, E. — Urocystis Violas and Ustilago antherarum Tubeuf, C. v. — Gymnosporangium Halsted, B. D. — New Antliracnose of Pepper Thaxter, R. — Sigmoideomyces , a new Genus of Hyphomycetes Fischer, E., F. Cohn, & J. Schroeter — Sclerote-forming Fungi Ellis, J. B., & B. Everhart — Sclerotoid Coprinus Masse, G. — Mycodendron, a new Genus of Hymenomycetes Dangeard, P. — Nucleus of the Oomycetes during Fecundation Brefeld, 0. — Hemiasci and Ascomycetes Prillieex, E. — Intoxicating Rye Jumelle, H. — Assimilation in Lichens Zahlbreckner, A. — Dependence of Lichens on their Substratum Hallauer, G. — Lichens of the Mulberry Dietel, P. — Structure of TJredineae „ „ Puccinia parasitic on Saxifragacese Magnus, P. — New TJredineae. Barclay, A. — Himalayan TJredineae Giard, A. — Entomophytic Cladosporieae Prillieux, E., G. Delacroix, Le Moult, & A. Giard — Parasite of the Cockchafer Trabut, L., & C. Brongniart — Parasite of Acridium peregrinum Hesse, R. — Hypogaei of Germany Yiala, P., & G. Boyer — Basidiomycete parasitic on Grapes Vuillemin, P. — Mycorhiza Frank, B. — Endotrophic Mycorhiza Mangin, L. — Disarticulation of Conids in the Peronosporeae Rush, W. H. — Penetration of the Host by Peronospora gangliformis .. Wevre, A. de — Biology of Phycomyces nitens Setchell, W. A. — Doassansia Kruger, W. — Fungus-parasites of the Sugar-cane Bommer, C. — Fungus parasitic on Balanus Marchal, E. — New Genus of Fungi ( Sphaeropsideae ) Zabriskie, J. L. — New Pestalozzia Humphrey, J. E. — Diseases caused by Fungi Prillieux, E., & Delacroix — Fungus-parasites on Pines Maule, C. — Fructification of Physcia pulverulenta Hansen, E. C. — Germination of Spores in Saccharomyces Part 4 >5 55 55 55 5* 55 Part 5 55 55 55 55 55 55 55 55 55 55 55 55 Part 6 55 55 55 55 55 55 55 55 55 55 PAGE 504 504 504 504 504 505 505 505 505 505 505 505 506 506 506 506 506 506 507 507 507 632 633 633 634 634 634 634 635 635 635 636 636 636 637 637 779 779 779 7S0 780 780 781 781 781 781 782 782 782 782 CONTENTS. XXXI Dietel, P .—Researches on Ur e din ex Barclay, A. — Uromyces Cunning liamianus sp. n Magnus, P. — Diorchidium Prillieux, E., & Delacroix — Parasite of the Cockchafer .. Thaxter, It. — New Genera of Hyphomycetes Ludwig, F. — Mucilaginous Slime on Trees Busquet, G. P. — New Achorion , A. Arloini Mycetozoa. Rex, G. A. — Development of Myxomycetes and new Species . . Wingate, H. — Orcadella , a new Genus of Myxomycetes Protophyta. a. Schizophyceae. Levi-Morenos, D. — Defensive structure of Diatoms Imhof, O. E. — Pelagic Diatoms Weed, W. H. — Vegetation of Hot Springs Beyerinck, M. W. — Zoochlorellx and Lichen-gonids Zukal, H. — Diplocolon and Nostoc GOMONT, M. — Oscillariacex Lanzi, M. — Classification of Diatoms Cox, J. D. — Nutrition and Movements of Diatoms Famintzin, A. — Symbiosis of Algx and Animals Tries, H. de — Aquatic Vegetation in the Dark Hieronymus, G. — Dicranochxte Cox, J. D., & M. J. Tempere — Coscinodiscex Cleve, P. T. — New Genera of Diatoms Muller, O. — Diatoms from Java Duchesne, L., & J. Pelletan — Pearls of Pleurosigma angulatum Cox, J. D. — Deformed Diatoms Hariot, P. — Polycoccus Macchiati, L. — Movement and Reproduction of Diatoms Schmidt’s Atlas der Diatomaceen-Kunde Borzi, A. — Dictyosphxrium, Botryococcus, and Porphyridium Massee, G. — Dictyosphxrium Onderdonk, U., & R. W. Haskins — Movements of Diatoms Reinhard, L. — Glceochxte Deby, J. — The Idea of Species in Diatoms Tempore, J., & H. Peragallo — Diatoms of France Brun, J., & W. H. Shrubsole — New Genera of Diatoms .. Peragallo, H. — Monograph of Pleurosigma Deby, J. — Auliscus Part 6 i) 99 99 99 99 99 Part 2 Part 3 Part 1 Part 2 99 99 Part 3 99 99 Part 4 Part 5 99 99 Part 6 99 99 99 99 &. Schizomycetes. Migula, W. — Drawings of Bacteria Part 1 Griffiths, A. B. — Researches on Micro-organisms „ Miquel — Milk and Coffee , and their Relation to Microbes „ Rafter, G. W., & M. L. Mallory — Septic and Pathogenic Bacteria . . „ Billet, A. — Study of Morphology and Development of Bacteriacex .. .. „ Lustig, A. — Red Bacillus from River Water „ Guignard, L. — New Marine Schizomycete , Streblothricia Bornetii .. .. „ PAGE 783 783 783 783 784 784 784 232 384 79 79 232 232 233 233 234 235 385 385 385 385 386 386 386 387 508 508 508 637 638 638 784 785 785 785 785 785 79 80 80 80 80 81 81 XXX11 CONTENTS. i Behr, P. — Non- for mat ion of Pigment by Bacillus of Blue Milk Lannelongue & Achard — Colour and Pathogenic Differences of Staphylo- coccus pyogenes aureus and S. albus Smith, T. — Acid- and Alkali-formation by Bacteria Royighi, A. — Germicidal Action of Blood in different conditions of organism Bitter, H. — Preservation and Sterilization of Milk W INOGR ADSKI, S. — Nitrification Frank, G. — Destruction of Anthrax Bacilli in the Body of White Bats Cornil, A. v. — Penetration of Glanders Bacillus through the intact Skin .. Machnoff, S. D. — Can Bacteria be introduced into the body by being rubbed in through uninjured skin ? . Lederer, M. — Effect of Micro-organisms on the Fowl-embryo Lustig, A. — Water Bacteria and their Examination Bouchard, 0. — Action of Products secreted by Pathogenic Microbes .. Fraenkel’s (C.) Bacteriology Kramer, C. — Bacteriology for Agriculturists Baumgarten’s (P.) Annual Report on Pathogenic Micro-organisms , including Bacteria , Fungi , and Protozoa Bibliography Koch, R., on Bacteriological Research Charrin, A., & G. H. Roger — Germicidal Action of Blood-serum Fodor, J. von — Germicidal Action of Blood Ransome, A. — Certain Conditions that modify the Virulence ‘of Tubercle- Bacillus Hankin, E. H. — Cure for Tetanus and Hydrophobia Winkler, F., & H. von Schrotter — Bacillus developing a Green Pigment Claessen, H. — Bacillus producing an Indigo-blue Pigment Kratschmer & Niemilowicz— Peculiar Disease of Bread .. Kitasato, S. — Growth of Bacillus of Symptomatic Anthrax on solid nutrient media Metschnikoff, E. — Studies on Immunity Kramer, E. — Mucous Fermentation Migula, W. — Bacteria in Water Zimmermann, O. E. R. — Bacteria of Chemnitz Potable Water Martin, S. — Chemical Products of Growth of Bacillus anthracis Bon arm, E., & G. G. Gerosa — Influence of Physical Conditions on the Life of Micro-organisms Petri, R. J. — Red Nitro-indol Reaction as a Test for Cholera Bacilli .. Plieque, A. F. — Tumours in Animals Lannelongue & Achard — Osteomyelitis and Streptococci Courmont & Jaboulay — Microbes of Acute Infectious Osteomyelitis .. Hueppe, F., & Petruschky — Controversy on Phagocytosis Zeidler, A. — Bacteria in Wort and in Beer Gunther’s (C.) Bacteriology Migula, W. — Bacteriology for Farmers Brieger — Bacteria and Disease Beyerinck, M. W. — Infection of Vida Faba by Bacillus radidcola Bein, — 5 Part 6 652 652 810 810 810 811 812 (4) Photomicrography. Mayall, J., jun. — Photomicrographs and Enlarged Photographs .. .. Parti 107 Walmsley, W. H. — Handy Photomicrographic Camera (Fig. 20) .. .. Part 2 257 Capranica, S. — On some Processes of Photomicrography „ 261 Taylor, T. — New Flash-light for Photography „ 263 Pringle, A. — Notes on Photomicrographs exhibited at R.M.S. , 19 Nov. 1890 „ 263 Fayel — Photomicrography in Space „ 265 Comber, T. — Photomicrography Part 3 407 Bibliography „ 411 Baker’s (C.) Photomicrographic Apparatus (Fig. 65) Part 4 525 Borden, W. C. — The Value of using different makes of Dry Plates in Photomicrography (Fig. 73) Part 5 653 Marktanner-Turneretscher’s (G.) 1 Die Mi'.rophotographie als Hilfsmittel Naturwissenschaftlicher Forschung ’ „ 657 Newhauss, R. — Magnesium Flash-Light in Photomicrography Part 6 812 LumieIre — Coloured Photomicrograms ,, 813 XXXVI CONTENTS. (5) Microscopical Optics and Manipulation. page Bausch, E. — The full Utilization of the Capacity of the Microscope, and means for obtaining the same (Figs. 7 and 8) Part 1 108 Blackham, G. E. — On the Amplifying Power of Objectives and Oculars in the Compound Microscope „ 114 Govi, G. — Constructing and Calculating Place , Position , and Size of Images formed by Lenses or Compound Optical Systems (Figs. 9 and 10) .. „ 122 Stevens, W. Le Conte — Microscope Magnification (Figs. 49 and 50) .. Part 3 412 Cox, J. D. — Diatom- Structure — Interpretation of Microscopical Images (Fig. 74) Part 5 657 Vanni, G. — Measurement of Focal Length of Lenses or Convergent Systems „ 665 Leroy, C. J. A. — Proof of simple Relation between Resolving Power of an Aplanatic Objectice and Diffraction of finest Grating which it can resolve „ 665 Czapski, S. — Probable Limits to the Capacity of the Microscope Part 6 814 Thompson, S. P. — Measurement of Lenses „ 818 Caplatzi, A. — Photographic Optics ,. „ 818 “ New Inventions (6) Miscellaneous. Part 1 126 Foster, M. — The late Mr. Brady , Hon. F.R.M.S. Angling and Microscopy The Microscope and the McKinley Tariff .. Lehmann, O. — Liquid Crystals (Plate F.) Landsberg, C. — History of Invention of Spectacles , Microscope , and Telescope Microscopes, Microtomes , and Accessory Apparatus exhibited at the Tenth International Medical Congress at Berlin International Exhibition at Antwerp Govi, G Schulze, A. P Curtice, C. — Method of Drawing Microscopic Objects by Use of Co-ordinates Carl Zeiss-Stiftung in Jena Death of Mr. Mayall The late Mr. Tuffen West, F.R.M.S. Joseph Leidy Dr. Dallinger’s Address to the Quekett Club The late Mr. John Mayall , Jr., Sec. R.M.S. Carl Wilhelm von Naegeli List of Patents for Improving the Microscope issued in U.S. from 1853-90 Newspaper Science Dallinger, W. H. — New Edition of Carpenter on the Microscope Death of Mr. F alter H. Bulloch Universal Microscopic Exhibition at Antwerp Meeting of American Microscopists Ebbage, H. — Recreative Microscopy Part 2 127 129 129 265 269 „ 271 „ 271 „ 272 „ 273 Part 4 527 „ 528 „ 529 „ 529 „ 532 Part 5 666 „ 673 „ 675 „ 676 „ 677 Part 6 819 „ 820 „ 820 „ 821 „ 823 fi. Technique. Bibliography Part 3 415 (1) Collecting- Objects, including Culture Processes. Hafkine, M. W. — Experiments on Cultivation Media for Inf usoria and Bacteria Part 1 129 Kuhne, W. — Silicic Acid as a Basis for Nutrient Media 130 Beyerinck, W. — Pare Cultivations of Green Unicellular Algse ft 130 CONTENTS. XXXV11 Petrl'SCHKY, J. — Flat Flask for cultivating Micro-organisms ( Fig . 11) .. Part 1 Karlinski, J. — Apparatus for filtering clear Agar (Figs. 12 and 13) .. „ Sc&ROTTER, H. YON, & F. Winkler — Pure Cultivations of Gonococcus .. „ Bujwid, O. — Simple Apparatus for filtering Sterilized Fluids (Fig. 21) .. Part 2 Brantz, C. — Apparatus for cultivating Anaerobic Microbes „ Prausnitz, W. — Method for making Permanent Cultivations Part 3 Tischutkin, N. — Simplified Method for Preparing Meat- Pepion- Agar .. ,, Overbeek de Meyer, van — Preparing Nutrient Agar „ Protopopoff, N., & H. Hammer — Cultivating Actinomyces „ Prausnitz, W. — Apparatus for facilitating Inoculation from Koch's Plates Gage, S. H. — Picric and Chromic Acid for the rapid Preparation of Tissues Prausnitz, N. — Apparatus for making Esmarch's Rolls „ Kamen, L. — New Cultivation Vessel „ Bibliography „ Bujwid, O. — Preparing Tuberculin Part 4 Gessard, C. — Preparing Pepton-agar for studying Pyocyanin „ Fowler, G. It. — Simple Method for sterilizing Catgut „ Schultz, N. K. — Preparation of Nutrient Media Part 5 Sacharow, N. — Preserving Malaria- Plasmodia alive in Leeches ,, Pasternacki, T. — Cultivating Spirillum Obermeieri in Leeches Kaufmann, P. — New Cultivation Medium for Bacteria Reichel’s Apparatus for Filtering Fluids containing Bacteria (Fig. 75) Winogradsky, S. — Organisms of Nitrification and their Cultivation .. Line, J. E. — A Colony- counter (Fig. 76) D’Arsonval, A. — Filtration and Sterilization of Organic Fluids by means of liquid carbonic acid „ n „ Apparatus for maintaining a Fixed Temperature .. .. „ Kirchner — Methods of Bacteriological Research Part 6 -Sleskin, P. — Silicate- jelly as a Nutrient Substratum „ Marpmann — Substitutes for Agar and Gelatin „ Stevens, T. S. — Miniature Tank for Microscopical Purposes „ Hopkins, G. M. — Apparatus for Gathering and Examining Microscopic Objects (Figs. 89 and 90) „ (2) Preparing- Objects. McMurrich, P. — Methods for the Preservation of Marine Organisms employed at the Naples Zoological Station Part 1 Lovett, E. — Hints on Preparation of Delicate Organisms for Microscope „ Morgan, T. H. — Improved Method of Preparing Ascidian Ova „ Eismond, J. — Simple Method of examining living Infusoria „ Czaplewski, E. — New Method for demonstrating Tubercle Bacilli in Sputum ,, Gasser, J. — Method for Differential Diagnosis of Bacilli of Typhoid ( Eberth ) „ Hovorka, O. von, & F. Winkler — New Criterion for distinguishing between Bacillus Choleras Asiaticas and the Finkler-Prior Bacillus „ Aubert, A. B. — Reference Tables for Microscopical Work „ Henchman, A. P. — Method of investigating Development of Limax maximus Part 2 Wagner, F. von — Method of observing Asexual Reproduction of Microstoma „ Neumann, E. — Examining Bone Marrow for developing Red Corpuscles . . „ Ranvier, L. — Study of Contraction of Living Muscular Fibres „ Fajerstajn, J. — Examining the Endbulbs of the Frog „ Ranvier, L. — Preparing Retrolingual Membrane of Frog to show junction of Muscular and Elastic Elements , and termination of Muscle Fibre . . „ PAGE 131 131 132 273 274 415 416 416 416 417 417 419 419 419 534 534 535 678 679 679 679 680 680 681 682 682 823 824 824 824 825 133 140 140 141 141 141 142 142 274 275 275 275 276 276 XXXV111 CONTENTS. Looss, A. — Examining histolytic phenomena in tail of Batrachian Larvae .. Laveran, A. — Examining the Blood for the Hxmatozoon of Malaria .. Hofer, B. — Hydroxylamin as a Paralysing Agent for small animals . . Poulsen, Y. A. — Preparation of Aleurone-grains Albert, A. B. — Reference Tables for Microscopical Work Schmidt, E. — Use of Gelatin in fixing Museum Specimens Auerbach, L. — Demonstrating Red Corpuscle Membrane of Batrachia M agin i, G. — New Characteristics of Nerve-cells .. .. Cox, W. H .—Impregnation of Central Nervous System with Mercurial Salts Smirxow, A. — Preparing Nervous Tissue of Amphibia Ballowitz, E. — Examining Spermatozoa of Insecta Mazzoni, Y. — Demonstrating Muscular Nerves in (Edipoda fasciata . . . , Trouessart, E. L. — Mounting Acarina Morgan, T. H. — Preparing Eggs of Pycnogonids Mayer, P. — Preserving Caprellidae Cobb, N. A. — Mode of studying free Nematodes Koch, G. y. — Mode of examining Calcareous Bodies of Alcyonacea Noll, F. C. — Demonstrating Structure of Siliceous Sponges Dreyer, F. — Demonstrating the Structure of Rotten-stone Thomas, M. B. — Collodion-method in Botany „ „ Dehydrating Apparatus (Fig. 66) Obregia, A. — Method for fixing Preparations treated by Sublimate or Silver ( Golgi’s Method ) HArG, R. — Decalcification of Bone Hoyer, H. — Demonstrating Mucin in Tissues Grandis, Y. — Preparing and Examining Glandular Epithelium of Insects Ritter, R. — Preparing and Staining the Ova of Chironomus Crosa, F. — Preserving Larvae of Lepidoptera with their Colour Oka, A. — Method of observing Pectinatella gelatinosa Apathy, S. — Demonstrating Tactile Papillae of Hirudo medicinalis Camerano, L. — Examining Ova of Gordius Cobb, N. A. — Study of Nematodes Woodworth, W. M. — Mode of Studying Phagocata Perry, S. H. — Study of Rhizopods Humphrey, J. E. — Demonstration of Cilia of Zoospores Van der Stricht, O. — Examination of Embryonic Liver Schafer, E. A. — Preparation of Wing-muscles of Insects Rohde, E. — Preparation of Nervous System of Hirudinea Ward, H. B. — Mode of Investigating Sipunculus nudus Brauer, A. — Development of Hydra Hertwig, R. — Study of Karyokinesis in Paramcecium Ward, H. B. — Method of Narcotizing Hy droids, Actiniae , §c Beyerinck, M. W. — Demonstrating Formation of Acids by Micro-organisms Eiselsberg, A. yon — Demonstration of Suppuration-Cocci in the Blood as an aid to Diagnosis Mann, Gustav — On a Method of Preparing Vegetable and Animal Tissues for Paraffin Imbedding , with a few Remarks as to Mounting Sections . . Strobel — Preserv ing Fluid Holl, M. — Investigation of FowVs Ovum Field, H. H. — Preparation of Embryos of Amphibia Burchhardt, R. — Investigation of Brain and Olfactory Organ of Triton o.nd Ichthyophis PAGE Part 2 277 99 99 99 99 Part 3 » a » >» >» » » 277 278 278 279 280 419 420 420 420 421 421 421 421 422 422 422 422 423 423 Part 4 535 „ 536 „ 537 „ 538 „ 538 „ 539 „ 539 „ 539 „ 540 „ 540 „ 540 „ 541 „ 541 „ 541 Part 5 683 „ 683 „ 684 „ 684 „ 684 „ 684 „ 685 „ 685 „ 686 „ 686 Part 6 827 „ 827 827 827 CONTENTS. XXXIX PACK Visart, O. — Preparing Epithelium of Mid-gut of Arthropods Part 6 828 Parker, G. H. — Mode of Preparing Crustacean Eyes „ 828 Bolsius, H. — Preparing Segmental Organs of Hirudinea ,, 828 Certes, A. — Eismond’s Method of Studying living Infusoria ,, 828 Macallum, A. B. — Demonstration of Presence of Iron in Chromatin by Microchemical Methods „ 828 Borzi, A. — Culture of Terrestrial Algae „ 829 Reinke, J. — Re-softening dried Algse „ 829 Moller, H. — Demonstrating Fungi in Cells „ 829 Roscoe, H. E., & J. Lunt — Mode of Investigating Chemical Bacteriology of Sewage .. .. „ 829 Favrat, A., & F. Christmann — Simple Method for obtaining Leprosy Bacilli from living Lepers „ 830 C3) Cutting", including Imbedding and Microtomes. Rowlee, W. W. — Imbedding Seeds by the Paraffin Method Part 1 143 Batjsch & Lomb — Microtome {Fig. 14) „ 145 Strasser’s (H.) Ribbon Microtome for Serial Sections {Figs. 22-26) .. .. Part 2 281 Miehe’s (G.) Improved Lever Microtome {Fig. 27) „ 283 Strasser, H. — Treatment of Paraffin-imbedded Sections {Figs. 28 and 29) .. ,, 285 Rcvwler, W. W. — Imbedding and Sectioning Mature Seeds Part 3 423 Aby, Frank S. — A Method of Imbedding Delicate Objects in Celloidin . . „ 424 Gage, S. H., & G. S. Hopkins — Preparation and Imbedding of the Embryo Chick {Figs. 67-68) Part 4 541 Webster, J. C. — An improved Method of preparing large Sections of Tissues for Microscopic Examination „ 544 Bessey, C. E. — Sections of Staminate Cone of Scotch Pine .. .. .. . . „ 546 Moll, J. W. — Sharpening Ribbon- Microtome Knives Part 5 689 To preserve Edges of Microtome Knives „ 689 (4) Staining and Injecting. S cheibenzuber, D. — Brown-staining Bacillus Part 1 146 Kuiine, H. — New Method for Staining and Mounting Tubercle Bacilli . . .. „ 146 Trenkmann — Staining Flagella of Spirilla and Bacilli „ 146 Matschinsky, N. — Impregnation of Bone Sections with Anilin Dyes .. .. „ 147 Tartuferi, F. — Metallic Impregnation of the Cornea Part 2 286 Kultschitzky, N. — Staining Medullated Nerve-fibres with Hsematoxylin and Carmine ,, 286 Schaffer, J. — Kultschitzky’ s Nerve-stain „ 287 Magini, G. — Staining the Motor Nerve-cells of Torpedo „ 287 Heidenhain — Fixing and Staining Glands of Triton helveticus „ 287 Griesbach, H. — Fixing , Staining , and Preserving Cell-elements of Blood .. „ 287 Cajal, S. R. — Staining Terminations of Tracheae and Nerves in Insect Wing Muscles by Golgi’s Method „ 288 Vasale, G. — Modification of Weigert’s Method Part 3 424 Mercier, A. — Upson’s Gold-staining Method for Axis-cylinders and Nerve- cells „ 425 Wolters, M. — Three New Methods for Staining Medullary Sheath and Axis- cylinder of Nerves with Hgematoxylin ,, 425 Tirelli, Y. — Staining Osseous Tissue by Golgi’s Method „ 426 Oyarzun, A. — Impregnating Brain of Amphibilia by Golgi’s Method .. .. „ 426 xl CONTENTS. Mercier, A. — Staining Medullary Sheath of Nerves of Spinal Cord and of Medulla Ciaccio, G. Y. — Demonstrating Nerve-end Plates in Tendons of Vertebrata Brazzola, H. — Preparing and Staining Testicle Stevenson, A. F., & D. Bruce — New Method of Injecting Fluids into the Peritoneal Cavity of Animals Valente, & G. d’Abundo — Demonstrating Cerebral Vessels of Mammalia .. Haug, R. — Three useful Staining Solutions Dogiel, A. S. — Fixation of the Stain in Methylen-blue Preparations .. Haug, R. — Preparation of Tumours injected during life with anilin pigments Ciaglinski, A. — Preparing and Staining Sections of Spinal Cord Honegger, J. — Manipulating and Staining old and over-hardened Brains . . Noniewicz, E. — Staining Bacillus of Glanders Evans, J. Fenton — Staining Pathogenic Fungus of Malaria Vinassa, C. — Characteristics of some Anilin Dyes Mann, G. — Staining of Chlorophyll Kaufmann, P. — New Application of Safranin Strauss — New Syringe for Hypodermic Injection Roux, G. — Colourability of Tubercle Bacilli Mallory, F. B. — Phospho-Molybdic Acid Hxmatoxylin Mann, Gustav — Methods of Differential Nucleolar Staining Obregia, A. — Method for fixing Preparations treated by Sublimate or Silver ( Golgi's Method) Burci, T. — Rapid Staining of Elastic Fibres Moeller, H — New Method of Spore-staining Mayer, Paul — Hsemalum and Hsemacalcium, Staining Solution made from Hsematoxylin Crystals Fraenkel (B.) on Gobbet’s Stain for Tubercle Bacilli .. Tavel — Syringes and their Sterilization Part 3 Part 4 55 5» 55 Part 5 55 55 55 Part 6 »> (5) Mounting1, including1 Slides, Preservative Fluids, &c. Faris, C. C. — To rectify Turpentine for Microscopical Use Part 1 Beck, J. D. — Can mounting media be improved for high powers by increasing the index of refraction ? Part 2 Stokes, A. C. — Useful Mounting Menstruum „ Vosseler, J. — Deterioration of Mayer’s Albumen-Glycerin Fixative .. .. Part 3 Suchannek, H. — Hints for fixing Series of Sections to the Slide „ „ „ Preparation of Venetian Turpentine „ Vosseler’s (J.) Cement and Wax Supports „ Pfeiffer, F. — Mounting Botanical Preparations in Venetian Turpentine . . Part 4 Aubert, A. B. — Deference Tables for Microscopical Work. III. Cements and Varnishes Part 5 (6) Miscellaneous. Rafter, G. W. — Biological Examination of Potable Water Part 1 Rosoll, A. — Tests for Glucosides and Alkaloids „ Hart, S. — Materials of the Microbe- Raiser „ A Query „ Giesenhagen, C. — Desk for Microscopical Drawing (Figs. 30 and 31) . . Part 2 Amann — Use of Polarized Light in Observing Vegetable Tissues Part 3 Pillsbury, J. H. — An Inexpensive Reagent Block (Fig. 69).. .. , . Part 4 Belzung, E. — Microscopic Diagnosis of Citric Acid in Plants „ PAGE 427 427 427 547 547 547 548 548 549 550 550 551 551 089 690 690 690 690 690 830 831 831 831 832 832 147 289 290 428 428 429 429 551 692 148 148 148 149 291 429 552 553 CONTENTS. Xli FAGB Ebstein, W., & A. Nicolaier — Artificial Preparation of the Sphseroliths of Uric Acid Salts Part 4 553 Sternberg, G. M. — Coco-nut-water as a Culture Fluid Part 5 693 Moore, S. Le M. — Microchemical Reactions of Tannin Part 6 833 Knauer, F., & J. B. Nias — Cleansing Used Slides and Cover-glasses .. .. „ 833 Nuttall, G. H. F. — Method for the Estimation of the actual number of Tubercle Bacilli in Phthisical Sputum „ 833 Aronson, H. — Colloidal Clay for Filtering Fluids containing Bacteria . . .. „ 835 Hopkins, G. M. — Some Suggestions in Microscopy {Figs. 91 and 92).. .. „ 835 Levi-Morenos, D. — Artificial Sea-water „ 836 Proceedings of the Society — December 17, 1890 Part 1 150 January 21, 1891 (Annual Meeting) „ 155 Report of the Council for 1890 „ 156 Treasurer’s Account for 1890 „ 158 February 18, 1891 Part 2 293 March 18, 1891 „ 297 April 15, 1891 , Part 3 430 May 20, 1891 ^ „ 432 June 17, 1891 Part 4 554 December 1, 1890 (Conversazione) Part 5 694 April 30, 1891 (Conversazione) „ 695 October 21, 1891 Part 6 837 November 18, 1891 „ 842 Index of New Biological Terms „ 849 Index „ 851 1891. d The Journal is issued on the third Wednesday of February, April, June, August, October, and December. 1891. Part 1. FEBRUARY. jTo Non-Fellows, \ Price 6s. Journal OF THE Royal Microscopical Society; CONTAINING ITS TRANSACTIONS AND PROCEEDINGS, AND A SUMMARY OF CURRENT RESEARCHES RELATING TO ZOOLO O'Y" -A^IKTID BOTANY (principally Invertebrata and Cryptogamia), MICROSCOPY, 4 SUMMARY OF CURRENT RESEARCHES RELATING TO tlie opinion which has been expressed by some writers, that their main purpose is to prevent the access of rain to the nectary. Variations in the Structure of the Acorn.* * * § — Prof. G. Stenzel de- scribes the variations in the structure of the fruit of Quercus pedunculata in the following points : — (1) In their size and shape ; (2) In the unequal size of the cotyledons ; (3) In the variable number of the cotyledons, which may be reduced to one either by the suppression of one or by coalescence, or may be increased to three or rarely to four ; (4) In the lateral position of the plumule ; (5) In the occurrence of two, or more rarely of three seeds in the ovary; (6) In polyembryony ; more than two embryos were never observed. Buds of Sempervivum and Sedum.f— Prof. A. Kerner v. Marilaun describes the structure of the buds which detach themselves for the pur- pose of propagation from Sempervivum arenarium and soboliferum and Sedum dasyphyllum. In the species of Sempervivum minute buds are formed in the axil of the leaves of the rosette ; these put out filiform stolons, the ends of which are densely covered with leaves ; these globular terminal portions become detached by the withering of the lower part of the stolon, are blown away, and develope into new plants. In Sedum dasyphyllum it is not uncommon for the flowers themselves to be meta- morphosed into a rosette of small leaves ; or buds may be found imbedded in the tissue of the upper surface of the very thick leaves of the central portion of the stem, or elevated on long stalks in the axil of the lower leaves. All these become detached and germinate in the same way. Dormant Buds in Woody Dicotyledons.* — M. A. Prunet states that all woody plants have dormant buds, but that these buds are often very small, and hidden in the bark ; microscopical examination is fre- quently necessary to determine their existence. Their connection with the pith of the stem is by means of a large medullary ray. These dor- mant buds are not only met with in the axil of ordinary leaves, but at the base of rudimentary leaves and bud-scales ; and one or more addi- tional buds often accompany the normal axillary bud. In exceptional cases the additional buds may appear opposite the point of emergence of the lateral foliar traces, in the axil of the plurifascicled leaves. The duration of dormant buds depends upon their means of defence against the sources of destruction, especially desiccation. Leaves of Nymphseace9e.§ — Prof. G. Arcangeli describes the structure of the submerged, aerial, and floating leaves of Nymphsea alba and Nuphar lutea , which agrees with the well-known features of the leaves of other water-plants. The formation of submerged leaves only in great depths he does not regard as the direct result of the greater depth of water, but rather as due to a weakening or decrease of vital energy, resulting from the greater depth of the roots below the surface. * Luerssen u. Haenlein’s Biblioth. Bot., Heft 21, 1890, pp. 4G-G5 (1 pi.). t Oesterr. Bot. Zeitschr., xl. (1890) pp. 355-7 (5 figs.). X Journ. de Bot. (Morot), iv. (1890) pp. 258-G3. § Nuov. Giorn. Bot. Ital., xxii. (1890) pp. 441-6. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 65 Leaves of Conifers.* — M. A. Daguillon draws the following conclu- sions from his work on the evolution of the leaves of the Abietineae : — (1) The existence of primordial leaves, that is, of leaves intermediate between the cotyledonary leaves and those of the adult plant, is con- stant. (2) The passage from the primordial form can take place without numerous transitions, as in Pinus , or by insensible gradations, as in Abies. (3) This passage is sometimes characterized by a modification in the phyllotaxis. (4) Sometimes also it is marked by a change in the state of the epidermal surface. (5) It is nearly always accompanied by the development, below the epiderm, of one or more sclerenchymatous layers, which afford the leaf protection and support. (6) The pericyclic sclerenchyme, which incloses more or less completely the median vein, acquires a considerable development. Further, among the two sorts of elements of which it is composed (cells with areolated punctations and. fibres with smooth membranes), the latter are often absent from the primordial leaves, appearing with the passage from the primordial to the definite form. (7) In certain genera (Abies, Pinus) the fibro vascular system of the median vein proceeding from a single bundle of the stem bifurcates in the interior of the adult, while it remains simple in the primordial leaf. (8) In all cases the number of the conducting elements of the xylem and of the phloem augments when the primordial passes to the mature leaf. (9) When the foliar parenchyme is heterogeneous and bifacial, the differentiation of the palisade-tissue is generally accen- tuated in the adult leaves. Leaves of Marine Phanerogams.! — Pursuing his examination of the leaves of aquatic plants, M. C. Sauvageau states that the family of Hydrocharidese contains only three genera adapted to live in sea-water, Enhalus, Thalassia, and HalopJiila. The leaf of Enhalus aceroides , be- sides its dimensions and absence of ligule, is distinguished from that of all other marine flowering plants by the long fibrous filaments, by the anatomy of the fibro vascular bundles, and by the double orientation of the fibrovascular bundles of the limb. TJialassia differs from Ew- halus in the structure of the limb, the two species of TJialassia differing from one another in the nature of the teeth at the extremity of that organ. In HalojpJiila there is but very slight differentiation in the structure of the leaf. The small genera Halodule and Phyllospadix present nothing very remarkable in the structure of their leaves. Halodule has secreting cells which are entirely epidermal ; both genera have non-lignified fibres in the vascular bundles between the xylem and the phloem. Summing up the conclusions of his study of the leaves of marine Phanerogams, M. Sauvageau states that if those flowering plants which live normally in the submerged condition are descended from terrestrial plants which have adapted themselves to this new mode of existence, the adaptation must have taken place in several different ways. The presence and the importance of a more or less lignified mechanical system vary greatly in the different genera. Except in the genus Halophila , * Eev. Gen. de Bot. (Bonnier), ii. (1890) pp. 154-61, 201-16, 245-75, 307-20, 345-58 (4 pis. and 68 figs.). f Journ. de Bot. (Morot), iv. (1890) pp. 269 73, 289-95, 321-32 (12 figs ). Cf. this Journal, 1890, p. 741. 1891. F 66 SUMMARY OF CURRENT RESEARCHES RELATING TO the anatomical study of the leaf is of great importance for the determi- nation of the genus and the species, the more so in consequence of the rarity of the flowers and of the fruits. Leaves of Aloinese.* * * § — Sig. D. Lanza describes the structure of the leaves in a large number of Aloinese, which agree in all essential characters. The cuticle varies greatly in thickness according to the species ; the epiderm is homogeneous, and is composed of a single layer of cells ; next to the epiderm comes an assimilating tissue, consisting of a very variable number of cells. Scattered through the assimilating parenchyme are a number of cells with suberized walls and sometimes of great length, containing raphides. The vascular bundles are of uniform structure throughout the order, and each is surrounded by its own endoderm ; the cells which contain the peculiar bitter principle constitute a layer outside the sieve-cells. The surface of the leaves of Haicorthia and Gasteria is covered with excrescences originating from below the epiderm, and composed of colourless cells, the function of which appears to be to protect the plant from excessive insolation. The author states that the leaves of Haicorthia fasciata altogether change their habit with the locality in which they grow, being flat or erect, according as they are exposed to shade or to sunlight. He finds no sufficient characters, either in the flower, the fruit, or the leaves, for distinguishing the genera Aloe , Gasteria , Haicorthia , and Apicra. Filaments in the Scales of the Rhizome of Lathraea squamaria.*— Herr A. Schenfel maintains his previous view that these structures are not of a waxy nature, but are living bacteria, of which he finds also the zoogloea-form. This view he supports by microchemical evidence against the adverse criticism of Jost. Their presence, or at all events their abundance, appears to depend on the richness in protoplasm of the scales or glands in connection with which they are found. Trichomes of Corokia budleoides.+ — Hr. A. Weiss describes the structure and the mode of development from a single epidermal cell of the remarkable hairs which cover both surfaces of young, but the under surface only of mature leaves, as well as the axis of this plant (Comaceae). They are of the form which he designates T-hairs, consisting of a very elongated cell fixed transversely at nearly its centre to a pedicel com- posed of four or five short cells. The membrane of the T-cell is largely impregnated with calcium carbonate ; and the hairs evidently serve the purpose of protecting the plant against the attacks of animals, and also against the penetration of the mycele of fungi. Bulbils of Malaxis.§ — According to Herr Y. A. Poulsen, the bulbils often found on the apices of the leaves of Halaxis palwlosa resemble ovules in having their axis clothed with an integument-like sheath. They have neither vascular bundle nor root, and are developed from the epiderm of the mother-leaf. New bulbils are sometimes formed at the margin of the sheath. * Malpighia, iv. (1890) pp. 145-67 (1 pi.). t Bot. Ztg., xlviii. (1890) pp. 417-30 (1 fig.). Cf. this Journal, 1889, p. 89. j SB. K. Akad. Wiss. Wien, xcix. (1890) pp. 268-82 (1 pi. and 1 fi?.). § ‘ Ora Bulbildannelsen hos Malaxia paludosa,’ Kjobenham, 1890. See Bot. Centralbl., xliii (1890) p. 336. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 67 Morphology of Utricularia.* — Prof. K. Goebel describes a number of species of Utricularia , chiefly from the East Indies. In U. orbiculata the embryo of the very small seeds has no radicle ; of the two minute cotyledons, one appears to develope into the first leaf, the other into the first bladder or into a stolon. The terrestrial species are divided into three groups — those in which the leaves are without bladders, those in which the leaves have bladders, and those in which the leaves have normal stolons. Of the leaves, Goebel describes six kinds, four of them belonging to the aquatic, two to the terrestrial forms. The stolons are of two kinds, leafy and leafless. In the aquatic species the leafy stolons are branching floating shoots, bearing the leaves in two rows ; in the terrestrial forms the leaves are usually dorsal, the stolons lateral or ventral. The leafless stolons may either bear bladders, or may be naked rhizoids without either leaves or bladders. The bladders are found on the primary shoot, on the stolons, and on the leaves. Each species has its own characteristic form of bladder, and these may be classified in three groups : — (1) Those of the aquatic species, which more or less resemble the bladders of U. vulgaris; (2) bladders with long antennae and the upper wall of the funnel elon- gated (JJ . orbiculata , cserulea, bifida, elachista, &c.) ; (3) bladders with broad funnel-like opening and a proboscis ( U . rosea , Warburgi sp. n., &c.). The stolons may be either axial structures or metamorphosed leaves. Structure of Sapindacese.t — Dr. L. Radlkofer discusses in great detail the anatomy and morphology, the limits and affinities, and the classification of the hundred and seventeen genera belonging to this natural order, which he divides into two suborders — the Eusapindaceae, with a solitary, apotropous, erect or suberect ovule in each loculus ; and the Dyssapindaceae, with two or more (rarely solitary) epitropous and pendulous ovules in each loculus. $. Physiology. (1) Reproduction and Germination. Hybridization and Crossing.}: — Herr W. Focke finds that, while lilies of the group L. bulbiferum are almost invariably sterile with their own pollen, they are readily fertilized by pollen from any other indi- vidual of the same group. The same is the case with Hemerocallis flava , and probably all other species except H. minor. A hybrid is readily obtained between Tragopogon pratense and T. porrifolitim . The two species of Melilotus, M. albus and M. macrorhizus , the one white, the other yellow, are both freely visited by honey-bees, which, as a rule, confine themselves rigorously to flowers of one colour on the * Ann. Jard. Bot. Buitenzorg, ix. (1890) pp. 41-119 (10 pis.). Cf. this Journal, 1889, p. 780. t SB. K. Bayer. Akad. Wiss. Miinchen, 1890, pp. 105-379. X Abhandl. Naturw. Ver. Bremen, xi, (1890) pp. 413-22. See Bot. Centralbl., xliii. (1890) p. 34. 68 SUMMARY OF CURRENT RESEARCHES RELATING TO same journey. It is, however, possible to obtain hybrids between the two species, and then the standard is always white, and all the remainder of the corolla yellow. A possible case of parthenogenesis in Bryonia dioica is recorded. Fertilization of Caryophyllaceae.* * * § — Prof. E. Warming describes the structure of the flowers of a large number of Scandinavian and Arctic Caryophyllaceae, especially in relation to the mode of pollination. Honey was found in all the species examined. The flowers are usually proterandrous ; the stamens borne on the sepals are developed first, then those borne on the petals, and finally the stigmas ; proterogyny occurs in a few species, and is apparently correlated with the reduction of the petals. The author confirms the observation of Muller that the degree of proterandry is in proportion to the size of the flower ; but the arctic species, even when large-flowered, are more inclined to homogamy than those from lower latitudes. Self-pollination is frequent, and results in perfect fructification ; anemophily is very rare, but occurs in Silene Otites. Many homogamous species are pleogamous, and these are generally gynodioecious ; this the author regards as not advantageous, but rather as a degeneration, caused by external or internal conditions. The larger flowers are usually hermaphrodite, while the smaller flowers are more or less reduced. Cleistogamous flowers are not uncommon. In many species the flowers remain closed in dark and cold weather, and are then self-fertilized. He does not find that the female are more fertile than the hermaphrodite flowers. Fertilization of Aracese.f — Prof. G. Arcangeli describes the pheno- mena connected with the opening of the inflorescence of Helicodiceros muscivorus (Araceae). The first day of the expansion of the spathe, he found imprisoned within it as many as 378 insects, of which 371 were Diptera, and 7 Coleoptera. From the entire absence of any digestive glands on the inner surface of the spathe, or any other organs for the absorption of nutritive material, he rejects Schnetzler’s explanation that the dead bodies of the insects serve for the nutrition of the plant, and believes that they assist in the process of pollination. Returning to the fertilization of Dracunculus, Prof. Arcangeli | adduces additional facts in favour of his view that the flowers of D. vulgaris are pollinated chiefly by necro-coleoptera. He was able to effect impregna- tion by the artificial introduction into the inflorescence of specimens of Saprinus and Dermestes which had already been pollinated. Artificial Germination of Milk-weed Pollen.§— Prof. B. D. Halsted has been able to germinate the pollen-grains which constitute the pollinia of Acerates viridiflorum (Asclepiadeae) by immersing them in agar, and was able to watch the very beautiful movements of protoplasm within the pollen-grain after it has put out its tube. These consist of a continuous current round the large vacuoles. The same phenomenon wras observed in various species of Asclepias. * Bot. Foren. F< stskr. (Copenhagen), pp. 194-296 (29 figs.), t Nuov. Giorn. Bot. Ital., xxii. (1890) pp. 467-72. j Malpighia, iv. (1890) pp. 254-61. Cf. this Journal, 1890, p. 629. § The Microscope (Trenton, N. J.), x. (1890) pp. 229-31 (4 figs.). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 69 Abnormal Germination of Acer platanoides.* * * § — M. L. J. Leger finds that in about 4 per cent, of the instances examined the.germination of the seeds of Acer platanoides was abnormal; the irregularity was in the following directions: — (1) one of the two cotyledons was more or less bifid ; (2) the number of cotyledons was three ; (3) each of the two cotyledons was split for 1/3 of its length ; (4) the number of cotyledons was four. The structure of the cotyledons is described in each of these cases, especially in regard to the arrangement of their vascular bundles. Dissemination of the Seeds of Harpagophyton.| — Herr P. Ascherson calls attention to the remarkable way in which the seeds of Harpago- phyton (Pedaliaceae) are disseminated in South Africa. The seed- vessels growing on the prostrate branches are covered with hooked appendages, which become fixed in the hoofs of antelopes and cattle. The violent stamping of the animal to get rid of the annoyance splits the hard pericarp and scatters the seeds. The characteristic hooked bristles on the seed-vessels are found even in the aquatic genus of the order, Trapella.\ Sesamum Schinzianum is characterized by the unusual occurrence on the same species of both extra-floral nectaries and a viscid hairy covering of the axis. (2) Nutrition and Growth (including- Movements of Fluids). Relations between Host and Parasite.§— Prof. H. Marshall Ward discusses some of the relations between host and parasite in certain epidemic diseases of plants. He shows that the conditions which are unfavourable to the vitality of the host are, in general, favourable to the rapid development and propagation of the fungus-parasite, causing especially thinness and softness in the cell-walls, and a greater perme- ability and less resistance in the protoplasm, with a larger proportion of organic acids, glucoses, and soluble nitrogenous constituents in the cell-sap. In the case of some of the fungi which are most destructive to plants, while the botrytis-form is saprophytic, the mycele is truly parasitic in the tissues of the host ; and this latter is especially vigorous and destructive where the botrytis-form has had abundaut food-material to live upon. In addition to a ferment or enzyme, the hyphm of the mycele have the power of developing large quantities of oxalic acid, which is especially destructive to the protoplasm of the host. Whether a given fungus exists as a parasite or as a saprophyte is, to a large extent, a question of nutrition. Parasitism of Orobanche.|| — Dr. G. Ritter Beck von Mannagetta gives the characters of the 13 genera of the order Orobancheae, and a complete monograph of the 82 species of Orobanche. With regard to their parasitism, he finds that, while a few species — 0. Laserpitii, Hederse, and Artemisise — are known only on a single host-plant, a much larger number grow on many indifferently, 0. minor on as many as 58 species. The natural orders to which the greatest number of the host-plants belong * Bull. Soc. Linn. Normandie, 1888-9 (1890) pp. 199-223 (1 pi.). f Verhandl. Bot. Yer. Brandenburg, xxx. (1889) pp. ii.-v. X Cf. this Journal, 1888, p. 992. § Proc. Roy. Soc., xlvii. (1890) pp. 393-443 (1G figs.). || Luerssen u. Haenlein’s Biblioth. Bot., Heft 19, 1890, 275 pp. and 4 pis. 70 SUMMARY OF CURRENT RESEARCHES RELATING TO are Leguminosre and Composite. With the exception that some hosts seem more favourable to the growth of the parasite than others, the same species of Orobanche growing on different host-plants presents no perceptible difference of any kind. On the other hand, they inflict great injury on many cultivated crops, especially hemp, clover, and tobacco. Phanerogamic Parasites.* — Dr. F. Johow gives a summary of all that is at present known with regard to parasitic flowering plants, which he classifies under four heads, viz. : — Euphytoids, which have developed from ordinary terrestrial autotrophous plants (Loran- thacese, most Santalacere, Rhinantheae, Orobancheae, &c.) ; (2) Lianoids, developed from climbing plants ( Cuscuta, Cassytha) ; (3) Epiphytoids, those that resemble epiphytes except in their parasitic habit (Loran- thaceae, some Santalaceae) ; (4) Fungoids, which present no relationship with any autotrophous group (Balanophoraceae, Cytinaceae). Each of these classes, except the last, may be again divided into Holoparasites and Hemiparasites. Some again are obligatory, and others facultative parasites. The total number of species known is somewhat over a thousand, of which about one-half belong to the Loranthaceae. As regards the choice of a host, some species grow only on a single host-species, as Loranthus aphyllus on Cereus peruvianus, Cuscuta Epilinum on the flax ; others only on different species of the same genus ; others only on different genera of the same family ; while others again have no such restrictions. Some again choose in preference different hosts in different districts ; thus, for example, the mistletoe grows in some regions almost exclusively on the apple, in others on the pine ; Arceu- thobium Oxycedri only on Juniperus Oxycedri in Europe; in North America on different species of Pinus. Many parasites confine their attacks to special parts of the host-plant ; as the Loranthaceae entirely to branches, the Balanophoraceae entirely to roots. The organ for the absorption of nutriment is, in all except the Cytinaceae, differenti- ated haustoria, which are apparently, from a morphological point of view, metamorphosed roots. In the Cytinaceae the entire vegetative structure of the parasite, imbedded in the interior of the host, serves as a haustorium. A special description is also given of the mode of parasitism in the different groups ; and the species or genera belonging to each are enumerated. Rooting of Bulbs and Geotropism.f — M. H. Devaux states that the anomalous method of rooting by means of stalked bulbs in the common tulip has been observed by Germain de Saint Pierre, Irmisch, and Royer. But this method of rooting is not confined to the tulip. In various species of Allium , Muscari, Scilla, Hyacinthus , Calystegia , Sagittaria , Tamus , &c., one or more internodes of the stem may become enlarged, and thrust vertically into the ground by their free extremity ; this extremity bears a bud which is destined to be transformed into a bulb or tubercle. '1 his phenomenon appears to be the result of geotropism. * Verhandl. Deutsch. Wissensch. Ver. Santiago, ii. (1890) pp. 68-105 (10 figs.), t Bull. Soc. Bot. France, xxxvii. (1890) pp. 155-9. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 71 Assimilation and Respiration.* * * § — Prof. Kreusler has determined, from experiments chiefly on the bramble and cherry-laurel, that the optimum temperature for the exhalation of carbon dioxide is about 45° 0., a rise of 5° above this showing a considerable diminution in the energy of the respiration ; he finds no confirmation of the theory of a “ post- mortal ” respiration. The assimilating energy shows no considerable variations between 15° and 30° C. ; above 30° it begins gradually to diminish, falling to zero at a temperature between 45° and 50° C. Assimilation by Red Leaves.f — From observations on the red varieties of the beech, the birch, and the sycamore, M. H. Jumelle concludes that in trees with leaves of a red or copper colour, chloro- phyllous assimilation is always less intense that in the same trees with green leaves ; in the case of the copper-beech and purple sycamore, this is reduced to one-sixth of the normal amount. Influence of high altitudes on Assimilation and Respiration. :J — As the result of a series of experiments on a number of species, chiefly herbaceous, Prof. G. Bonnier finds that in the same plants, placed in the same external conditions, the specimen grown in an alpine climate modifies its functions by the augmentation of chlorophyllous assimilation and transpiration, while respiration and transpiration in the dark appear to be scarcely affected by the change. Permeability of Wood to Air.§ — M. Kruticki distinguishes in this respect three classes of wood, viz. (1) Those which present great permeability, as the oak and poplar, in which the air can penetrate under a pressure of from 3 to 10 mm. of mercury; (2) Those of low permeability, like the birch and maple, which require a pressure above that of the atmosphere ; and (3) Those of moderate permeability, which are very numerous. The air contained in the branches has not always the same composition ; in winter it contains less oxygen than the atmo- spheric air, but a larger proportion of nitrogen, and especially of carbonic acid ; with the commencement of spring, the proportion of oxygen increases, while that of carbon dioxide diminishes, so that when the buds expand, the composition of the imprisoned air is very nearly that of the atmosphere. C3) Irritability. Action of Water on Sensitive Movements.|| — M. H. Leveille gives the details of an experiment on this point with Mimosa rubricaulis ; the following conclusion was arrived at : — plants, if placed under water, retain their sensitiveness as long as they retain any vigour. Movements of the Leaves of Porlieria hygrometrica.1T — Dr.G. Paoletti states that the diurnal movements of the leaves and leaflets of this plant (Zygophyllacese) is due to unequal turgidity of the two cells * SB. Niederrhein. Gesell. (Verhandl. Naturhist. Ver. Preus. Rkeinl.), lxxiv. (1890) pp. 54-60. f Comptes Rendus, cxi. (1890) pp. 380-2. % T. c., pp. 377-80 ; cf. this Journal, 1890, p. 486. § Script. Bot. Hort. Univ. Imp. Petropolitame, ii. See Bonnier’s Rev. Gen. de Bot., ii. (1890) p. 324. || Bull. Soc. Bot. France, xxxvii. (1890) p. 153. II Malpighia, iv. (1890) pp. 31-40. 72 SUMMARY OF CURRENT RESEARCHES RELATING TO which compose the primary and secondary motor nodes (those of the entire leaf and of the leaflets), caused by the greater amount of light and heat to which the upper one of the two is subject in the morning. If exposed either to continuous darkness or to continuous light, the move- ments will continue for some days, but with decreasing energy, and will finally cease altogether, (4) Chemical Changes (including Respiration and Fermentation). Formation of Albuminoids.* — In order to test the correctness of the theory that the chromatophores are the seat of the synthesis of the albuminoids in plants, M. Chrapowicki cultivated plants of Phaseolus vulgaris , Cucurbita Pepo, and Zea Mays in a non-nitrogenous saline solution obtained by replacing the potassium and calcium nitrates in Knop’s solution by potassium chloride and calcium sulphate. The development was at first normal, but was soon retarded and finally entirely arrested. The leaves were cut off and placed in normal Knop’s solution, and the formation of the albuminoids watched under the Microscope. They were formed at the expense of the nitrates in the solution, and always made their appearance first in the chromatophores. ■y. General. Action of Solar Heat on the Floral Envelopes.! — M. E. Roze has endeavoured to determine by experiment whether the direct effect of the sun’s heat varies with the different colours of flowers. When a flower which has opened in the shade is suddenly exposed to solar radiation, it absorbs at first a certain quantity of heat, then rapidly gives off a large portion of this caloric, and, if then again placed in the shade, gradually loses the absorbed heat, and places itself in equilibrium with the temperature of the surrounding air. Red or violet floral envelopes absorb and give off more rays of heat than blue or yellow, and these latter more than white. A thermometer placed over the first rises, when transferred from the shade to the sun, as much as 8 3 ; one over the second 6°-7D ; over the third 5°-6° ; while over green leaves it does not rise more than from 2° to 3°. These latter absorb as much heat as petals, but give off again only a small quantity. This radiation of heat from the petals has probably a great effect in promoting the dehiscence of the anthers. The author found also that heat is powerfully absorbed by the soil from the sun’s rays, and is given off again to the whole plant, and especially to the parts in contact with the earth. A thermometer placed above the prostrate leaves of Plantago major rose to 44°, and in the case of Hypochseris radicata to 46', while the temperature of the surrounding air was only 28°. Biology of the Ericaceae.! — M. L. Fliche has examined various species of Ericaceae with a view to determine the quantity of mineral elements which they require. He finds that the plants belonging to * Arb. St. Petersburg Naturf. Gesell., xviii. See Bonnier’s Rev. Gen. de Bot.. ii. (1890) p. 359. t Bull. Soc. Bot. France, xxxvi. (1889), Aetes du Congres de Bot., pp. ccxii.-ccxiv. 1 Rev. des Eaux et Forets, Nov. 10, 1889, See Bull. Soc. Bot. France, xxxvii. (1890), Rev. Bibl., p. 107. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 73 this order can be classed under two categories, calcifugous and calci- colous ; the composition of the ash being nearly uniform in each class ; but the difference between the two is very pronounced, although some genera, such as Erica, have representatives in eaoh group. In the calcifugous species, e. g. Erica cinerea, Calluna vulgaris, the propor- tion of silica in the ash is very high, sometimes exceeding 30 per cent., while that of lime is not more than 20 per cent. ; in the calcicolous species such as E. multijlora, the proportion of silica is not more than 13 per cent., while that of lime may be as much as 31, and that of potassa as much as 22 per cent. Myrmecophilous Plants.* * * § — Herr K, Schumann describes a number of fresh myrmecophilous trees and shrubs, chiefly from the East Indian Archipelago, viz. : — Gmelinia ( Vitex ) macrophylla (Verbenacea?) ; among Rubiaceae Bemijia physophora and Nauclea lanceolata, where the ants inhabit chambers in the stem, and Myristica heterophylla sp. n. B. CRYPTOGAMIA, Cryptogamia Vascularia. Sphenophyllum and Asterophyllites-f— From examination of a specimen from the Carboniferous strata of Silesia, Mr. A. C. Seward concludes that Aster ophyllites is not a distinct genus of Vascular Cryptogams, but that it must be regarded as a morphological condition of Sphenophyllum, with reduced leaves having only a single vein. Muscineae. Peristome. J — M. Philibert now brings to a close his discussion of the differences between the Nematodonteae and the Arthrodonteae, and the transitions between these two groups. The following are the author’s conclusions: — That the Nematodonteae attain their highest degree of de- velopment in the Polytrichaceae, having probably passed through a series of stages of less complexity, corresponding to the series of Dawsonieae. The Arthrodonteae give rise to a great variety of forms. The Lepto- stomeae and the Splachnaceae appear to have preserved traces of forms transitional between the Nematodonteae and the Diplolepideae ; the Eunariaceae and the Orthotricliaceae resemble the latter in certain characters. There is also an affinity between the genera Splachnum and Bryum ; and to the Bryaceae belong the Hypnaceae, and all the Pleuro- carpeae, whose development has been posterior to that of other mosses. Microspores of Sphagnaceae.§ — Herr S. Nawaschin maintains that the so-called microspores of certain species of Sphagnum belonging to the acutifolium group are not organs of the moss itself, but are spores of a parasitic fungus belonging to the Ustilagineae, probably an undescribed species of Tilletia. Javanese Hepaticae.|| — Under the name Treubia Prof. K. Goebel describes a new genus of Hepaticae from Java, belonging to those * Verhandl. Bot. Ver. Brandenb., 1890, pp. 113-23. Cf. this Journal, 1890, p. 486, t Mem. and Proc. Manchester Lit. and Phil. Soc., 1890 (3 figs.). X Rev. Bryol., xvii. (1890) pp. 39-42. Cf. this Journal, 1890, p. 488. § Bot. Centralbl., xliii. (1890) pp. 289-90. |j Ann. Jard. Bot. Buitenzorg, ix. (1890) pp. 1-40 (4 pis,). 74 SUMMARY OF CURRENT RESEARCHES RELATING TO which form a link between the thalloid and the foliose forms. While the leaves are the largest known among Hepaticae, the position of the sexual organs (archegones only have at present been observed) allies it with the thalloid forms. The cells of the stem are infested by a parasitic, or possibly symbiotic, fungus. Colura ornata sp. n. is epiphyllous ; the water-sack characteristic of the genus is surmounted by a comb-like projection from the surface of the leaf. A species of Plagiochila with water-sacks is also described. Kurzia crenacanthoidea , described by its discoverer as an alga, is in reality a species of Lepidozia with confervoid habit. Characeae. Histology of Characese.* — Dr. W. Overton’s researches on this subject relate mainly to two points : — (1) The nature of the spiny bodies found in the cells. The species examined for this purposes was chiefly Nitella syncarpa. They were found in all the mature internodes of the stem and leaves, where they obtain a diameter of 22 to 24 p, in the young oospheres, in the cortical cells of the oosperm, in the shield-cells of the antherids, occasionally in the manubria, but not in the other cells of the antherids. They are clothed with a distinct membrane, and often occur in dense masses, wdien they assume a polygonal form. Microchemical reactions show that they are of a proteid nature, and that they frequently contain tannin ; they are peculiarly resistant to the action of acids, even when concentrated. They may be compared to a certain extent with aleurone-> grains. The living cells of young internodes contain also a number of hyaline vesicles imbedded in the protoplasm, which are also clothed with a distinct membrane, and are clearly of a similar nature to the spiny bodies. In the species of Ghara examined ( G . fragilis and hispida ) no structures were found resembling either of those above described. (2) The structure of the hard envelope of the oosperm. This envelope is not lignified in the correct sense of the term ; i. e. it does not show the microchemical reactions of lignin, but rather those of cuticularized and suberized membranes. After removal of the calcareous deposit, the envelope of the oosperm of Gliara fragilis consists of three layers: — the outermost is nearly black, is furnished with spiral thickening- bands, and bears a number of short spines ; the middle layer is brown and smooth ; the innermost is the true membrane of the oosperm, is light brown and transparent, and is but slightly cuticularized. Algae. Algae of Behring’s Sea.f — Ilerr F. E. Kjellman describes the sea- weeds of this sea, which are partly of an Arctic, partly of a more southern character, with some peculiar to the region. Several new species are described, and one new genus of Phaeosporeae, Analipus, with unilocular zoosporanges, a horizontal almost crustaceous thallus, from which rise the fertile branches, simple, solid below and fistulose above. * Bot. Centralbl., xliv. (1890) pp. 1-10, 33-8 (1 pi.). f K. Svensk. Ve tensk.-Akad. Handl., xxiii. (1889) 58 pp. and 7 pis. See Bot. Centralbl., xliv. (1890) p. 150. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 75 Sargassum.* * * § — Prof. J. G. Agardli publishes a monograph of this genus of seaweeds, with a description of the different forms assumed by the various organs. 143 species are described, of which 24 are new. The author classifies them under five subgenera, viz. : — PJiyllotricha, Schizo- phycus , Bactrophycus, Arthrophycus, and Eusargassum , founded generally on the form and disposition of the receptacles. Of the five subgenera, Schizopbycus comprises only a single species, while 93 are included in Eusargassum. New Genus of Phseosporeae.j — M. E. Bornet proposes the new genus Zosterocarpus , founded on Ectocarpus (Edogonium Men., which he separates from Ectocarpus with the following diagnosis : — Thallus monosiphonius ramosus ; sporangia plurilocularia divisione peripherica articulorum exorta, soros crustiformes orbiculares v. annuliformes in ar- ticulis ramulorum formantia ; cellulae singulae sporangiorum simplices breves haud septatse apice poro apertse. Prasiola and Schizogonium. — M. E. de Wildeman considers that it has been established that Schizogonium and Hormidium are simply forms of development of the same organism. The family Ulotrichese must therefore be reduced to the genus Hormiscia alone of the genera included under it by De Toni, to which should be added Prasiola , which the author proposes to remove from Ulvaceae, and thinks it pro- bable that to it will finally be referred the species at present placed in Schizogonium. Myxochaete, a new genus of Algae. § — Under the name Myxochsete barbata, Herr K. Bohlin describes a new species and genus of green algae, growing in fresh water, epiphytic on Vaucheria sessilis, and nearly allied to Chsetopeltis. The thallus is discoid, and usually consists of a single layer of cells, is invested in mucus, and each cell is provided with two hyaline bristles ; the branches are irregularly aggregated, and each cell contains a single chlorophyll-mass. Neomeris and Bornetella.|| — Prof. 0. Cramer describes a number of species of the verticillate Siphoneae, chiefly belonging to the above- named genera, viz. : — Polyphysa Peniculus , Botryopliora Conquerantii , Neomeris Kelleri , N. dumetosa , Bornetella nitida , B. capitata. Observation of the structure of the mantle- sheath, and of the mantle- caps, especially in Neomeris and in Bornetella, lead Prof. Cramer to the conclusion that they are formed by intussusception. By the mantle- cap is meant the upper deciduous, by the mantle-sheath the lower permanent portion of cellulose layers formed over the apical cell between the layers of hairs ; this last becomes at length strongly calci- fied ; the others are free from lime. The sporanges and spores are described in both these genera ; also cubical crystalloids in the cells of * Handl. K. Svenska Vetensk.-akad., 1889, 133 pp. and 31 pis. See Bull. Soc. Bot. France, xxxvii. (1890) Kev. Bibb, p. 110. f Bull. Soc. But. France, xxxvii. (1890) pp. 139-48 (1 fig.). j Bull. Soc. Belg. Microscop., vi. (1890). See Notarisia, v. (1890) p. 1035. § Bib. K. Svensk. Akad. Handl., xv. (1890) 7 pp. and 1 pi. || Denkschr. Schweiz. Naturf. Gesell., xxxii. (1890) 48 pp. and 4 pis. Cf. this Journal, 1888, p. 464. 76 SUMMARY OF CURRENT RESEARCHES RELATING TO the stem of Botryopliora Conquerantii , and spherocrystals of inulin in sterile specimens of the same species. Phytophysa.* — Under the name Phytophysa Treubii , Mdme. Weber van Bosse describes an epiphyllous alga from Java belonging to the Phyllosiphonaceas, found on the stems, leaves, leaf-stalks, and buds of a species of Pilea , where it causes internal galls. Phytophysa resembles Phyllosiphon in its manner of living, in part, at least, at the expense of its host. Both are surrounded by a thick membrane ; Phyllo- siphon is rich in grains of starch, Phytophysa in grains of cellulose ; in both each cell contains a considerable number of minute nuclei. Phyto- physa is distinguished from Phyllosiphon by its spherical form, and by producing galls. Gonium pectorale.j — Dr. W. Migula has subjected this organism to a careful investigation, and finds that the entire colony, as well as each individual cell, is inclosed in a mucilaginous envelope, often of extreme tenuity, and of nearly the same refrangibility as water. The interstitial space between the envelopes of the separate cells is composed of a central quadrangle and four longer and twelve shorter isosceles triangles. When the colony consists of only four cells, there are two more or less regular usually isosceles triangles, thus presenting a clear distinction from G. tetras , in which the four cells are arranged around a nearly square intercellular space. The young colonies are already surrounded by their envelope when they escape from their mother-colony. The protoplasm of the cilia presents somewhat different reactions from that of the cells, and their vibratility is confined to their apical portion. When cell-division is taking place, the cilia of the mother- cell persist often until the sixteen daughter-cells are fully formed. The movement of the colony is of a more trembling nature than that of Volvox ; and there are no protoplasmic threads connecting the cells. The Gonium-colony enters into a resting condition as a result of desicca- tion, closely resembling that of Pandorina ; the membranes become thicker and denser, and the cilia disappear, as do finally the pigment-spot and the two cilia. The resting-cells have a diameter of about 12-15 p ; they are dark green, and are filled with a granular endochrome. Each breaks up on germination into four biciliated swarm-cells, closely resem- bling the cells of an ordinary Gonium- colony, but at first wanting the mucilaginous envelope, which, however, is soon formed ; these developed, as far as was seen, only into four-celled colonies. In the resting con- dition the Gonium- cells are very liable to be attacked and entirely de- stroyed by a parasite. The chromatophores break up very readily into a number of very minute chlorophyll-granules. Fossil Algae. J — M. G. Maillard classifies all structures described as fossil algaB under two categories, viz. : — (1) Those which appear as simple half-cylindrical elevations on the under-side of the strata, and are always more or less compressed. (2) Those which can be separated from the rock in which they are imbedded. To the first category, the * Ann. Jard. Bot. Buitenzorg, viii. (1890) pp. 165-88 (3 pis.). t Bot. Centralbl., xliv. (1890) pp. 72-6, 103-7, 143-6 (1 pi.). j Mem. Soc. Pakeontol. Suisse, xiv. (1887) 5 pis. See Bot. Centralbl., xliii. (1890) p. 126. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 77 algal nature of which is very doubtful, belong the greater number of palaeozoic forms, such as Crossochorda , Cruziana , and Harlania, and possibly also Spirophyton and Alectorurus ; in the mesozoic strata, Helminthopsis, Gyrochorte , and Gylindrites , from the Lias ; from the tertiary strata, Helminthoidea , Palseodictyon, and Miinsteria from the alpine Flysch. The second category, which he regards as comprised of true fossils, includes Chondrites and Theobaldia, and probably also Discophorites and Gyro- phyllites from the Jurassic, Taonurus and Nulliporites from palaeozoic strata ; Chondrites , Taonurus , Caulerpa , Sphserococcites , Discophorites , and Gyrophyllites from the chalk ; Chondrites , Caulerpa , Tsenidium, Halymenites , Hormosira, Sphserococcites, Gyrophyllites , Nulliporites , Aula- cophycus, and Taonurus from tertiary strata. As regards the systematic and phylogenetic position of these algae, he considers that we have very little evidence. Fungi. Carbohydrates in Fungi.* * * § — M. E. Bourquelot gives a resume of the results of his analyses of the genus Lactarius. Mannite, volemite, trehalose, and glucose were the hydrocarbons found ; the proportion, however, of these varies from' one species to another, and even from one year to another in the same species. New TJstilaginese.t — In a general summary of the UstilaginesB of Denmark, comprising 47 species, Herr E. Rostrup describes the following as new : — Entyloma Ossifragi, parasitic on Narthecium ossifragum, E. catenulatum on Air a csespitosa , Ustilago Pinguiculse on Pinguicula vulgaris , Tuberculina maxima on Peridermium Klebahni, itself parasitic on Pinus Strobus. Dissociation of a Lichen.} — Sig. U. Martelli records the natural dissociation of a lichen, a variety of Lecanora subfusca, into its con- stituent algal and fimgal elements. The central portion of the patches, which were growing on an old wall, were of a deep green colour, caused by large masses of Protococcus viridis ; while the periphery consisted of nearly colourless mycelial filaments. The cause of this dissociation appears to be excessive humidity, which prevents the fungus putting out its “ crampons ” or short filaments which take up the gonids. Bouquet of Fermented Liquors.§ — The opinion long ago expressed by M. Pasteur that the flavour and special qualities of certain wines are due to their particular ferment, finds support from the fact recorded by M. G. Jacquemin, who, in endeavouring to impart flavour to barley wine by making it from wort leavened with the special ferments of wines of delicate flavour, found that the sugar- water in wrhich the fer- ment was kept obtained the exact flavour of the various wines used, such as Champagne or Burgundy. He also imparted the flavour of apples and pears by using their ferments in barley wort. * Bull. Soc. Mycol., v. See Rev. Mycol., xii. (1890) p. 192. Cf. this Journal, 1890, p. 644. t ‘ Ustilaginese Danise,’ Kjobenbavn, 1890, 52 pp. See Bot. Centralbl., xliii. (1890) p. 388. X Nuov. Giorn. Bot. Ital., xxii. (1890) pp. 450-1. § Comptus Rendus, cx. (1890) pp. 1140-2. 78 SUMMARY OF CURRENT RESEARCHES RELATING TO Indian Rusts and Mildews.* — According to Dr. A. Barclay, the most prevalent form of rust on wheat, barley, and oats in India, is not Puccinia graminis , but P. rubigo-vera ; the eecidio-form appears to occur on Berberis Lycium. The following rusts occurring in India are also described: — Puccinia Sorglii on Sorghum vulgare , Melampsora Lini on flax, Uromyces Pisi on Cicer arietinum and on Lathyrus sativus, Puccinia Fagopyri on buckwheat. Puccinia digraphidis.f — By culture experiments, Mr. H. T. Soppitt has proved that the aecidium of Convallaria majalis known as AEcidium Convallarise is a heteroecious Uredine, and that the host which bears the uredo- and teleuto-spores is Phalaris arundinacea. For the uredospore generation he proposes the name Puccinia digraphidis. NewRamularia on Cotton4 — Under the name Pamularia areola , Prof. G. F. Atkinson describes a new parasitic fungus forming brown spots on the under side of the leaves of the cotton-plant in Alabama. Uredo notabilis.§ — Among other new fungi from Australia, Herr F. Ludwig describes this remarkable species of Uredo , parasitic on the phyllodes of Acacia notabilis. It causes conspicuous inflated bladders, as much as three cm. in diameter; the epispore of the uredospores is distinguished by its remarkable reticulate sculpture, so that they might readily be taken for teleutospores. A beautiful new Clathrus, C. ( Ileodictyon ) Tepperianus , is also described from South Australia. iEcidium Schweinfurthii.|j — Under this name Herr P. Hennings describes a remarkable new species of parasitic fungus which causes large galls on the ovary or young fruit of Acacia fistula in Central Africa. New Type of Dermatomycosis.1T — M. R. Blanchard describes a disease in the skin of a green lizard, in the form of tumours produced by a mucedineous fungus belonging to the genus Fusarium or Selenosporium. The tumours are permeated throughout by septated conids springing from mycelial filaments of two kinds, acrogenous, and springing laterally from the mycele. The author regards this as an example of a fungus ordinarily saprophytic, which becomes parasitic under exceptional con- ditions. Phalloideae.** — Dr. E. Fischer gives a complete account of the history of development of the Phalloideas, which begins with the broadening of the end of a hyphal bundle, in which the central bundle and the volva-jelly are formed as denser portions of the tissue, while between these there remains an intermediate tissue which is not at once differen- tiated. The first differentiations of this intermediate tissue bring about the variations in the form and structure of the receptacle, and of the distribution of the glebe, which afford specific characters. From this * Journ. of Bot., xxviii. (1890) pp. 257-61 (1 pi.). f T. c., pp. 213-6. X Bot. Gazette, xv. (1890) pp. 166-8 (4 figs.). § Bot. Centralb]., xliii. (1890) pp. 5-9 (2 figs.). || Abhandl. Bot. Verein. Brandenburg, xxx. (1890) pp. 299-30P. If Comptes Rendus, cxi. (1890) pp. 479-82. ** Denkschr. Schweiz. Naturf. Gesell., xxxii. (1890) 103 pp. and 6 pis. See Bot. Ztg., xlviii. (1890) p. 496. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 79 point the development of the receptacle is very uniform. As regards classification, the author first divides the Phalloidese into the Clathrefe and Phalleae; Kalchbrennera being nearly related to the former. The genera are then described in detail, many of those belonging to the Clathreoe passing gradually one into another. New Genera of Basidiomycetes.* — In a critical account of the Gasteromycetes and Hymenomycetes of Finland, comprising 1255 species, Herr P. A. Karsten describes, in addition to a large number of new species, the following new genera: — Phisisporinus (Polyporeae, separated from Poria'), Onnia (Polyporeae, separated from Polyporus ), Elfvingia (Polyporeae, from Forties ), Kneiffiella (Grandinieae, from Hydnurri), and the following under Thelephoreae : — Lomatia (separated from Thelephora), Sterellum (from Stereum), Chsetocarpus (from Thele - pliora ), Trichocarpus (from Xerocarpus ), Cryptochsete (from TJielephora and Corticium ), Phanerochsete (from Thelephora ), P eniophorella , Hymeno- chaetella , Gloeocystidium (from Grandinia ), Diplonema , ConiophoreUa (from Hypochnus), Hypochnopsis (from Hypochnus and Lyomyces). Protophyta. a. Schizophyceae, Defensive Structure of Diatoms.t — Continuing his observations on this subject, Dr. D. Levi-Morenos classifies the general forms of diatoms under three heads, viz.: — (1) Spherical, with polyhedral, conical, and cylindrical derivatives. (2) Fusiform, with naviculoid and bacilliform derivatives. (3) Irregular, with bi-, tri-, and pluripolar derivatives. In each group those forms appear to have specially survived which were best calculated, in the modes already indicated, either to resist being swallowed by aquatic animals, or, if swallowed, to emerge rapidly and uninjured from the intestinal canal. Pelagic Diatoms. J —Sig. O. E. Imhof has examined the pelagic flora of the Lake of Zurich at depths varying from 30-60 metres, and finds diatoms at all these depths, accompanied by a few Nostocaceae, Oscillariaceae, and Chroococcaceae, and by abundance of Schizomycetes. At a depth of 60 metres the following diatoms were found, — Asterionella formosa , Nitzschia pecten , Synedra longissima , Cymatopleura elliptica , Diatoma sp., Fragillaria sp., and Cyclotella sp. ; while at a depth of 100 m. Anabsena circinalis was abundant. The numbers of the two first- named diatoms were greater at a depth of 80-90 m. than at lesser depths. £. Schizomycetes. Drawings of Bacteria. — The authorities of the Natural History Museum, South Kensington, have placed in the central hall of that institution a small temporary exhibit, consisting of a set of highly magnified drawings of bacteria. It includes such prominent forms as Bacillus tuberculosis Koch and the bacillus of fowl-cholera, and is the work of Dr. W. Migula. * ‘Kritisk Ofversigt af Finlands Basidsvampar,’ Helsingfors, 1889, 470 pp. S^e Bot. Centralbl., xliii. (1890) p. 383. t Notarisia, v. (1890) pp. 1007-14, 1092-6. See this Journal, 1890, p. 650. j^Notarisia, v. (1890) pp. 996-1000. 80 SUMMARY OF CURRENT RESEARCHES RELATING TO Researches on Micro-organisms.* * * § — Dr. A. B. Griffiths in the third part of his communications deals first with the alkaloids of living microbes, the origin of which is not yet thoroughly understood. In examining the action of certain antiseptics and disinfectants on microbes, he found that Bacillus tuberculosis , B. subtilis, B. cedematis maligni , Bacterium allii , or Beneke’s Spirillum may have their growth inhibited by three per cent of salicylic acid. Various microbes are capable of being dried up in the dust of the atmosphere for several months without losing their vitality. Observations have been made on the effect of cold and of electrical currents, and the latter were proved to be powerful germicides. There are a larger number of micro-organisms in the summer than either in the spring or winter, and they appear to reach their maximum during the month of August. The number in the air decreases as one ascends. There are more in crowded than in less densely popu- lated centres, and there are fewer when the air is at rest than at any other time. Dr. Griffiths thinks that the most rational method of treating contagious diseases where microbes reside in the blood is by the injection of some germicidal agent. Milk and Coffee, and their Relation to Microbes-t — M. Miquel gives a resume of his observations on the number of microbes present in milk. In a cubic centimetre of milk, on its arrival at the laboratory, which was two hours after it had been taken from the cow, 9000 bacteria were found. In another hour 31,750 were found, while in 25 hours there were over 5,000,000. The number of microbes varies much with the temperature ; for example, if the milk is raised 25°, the number of germs is enormous. The greater part of these microbes are innocuous ; many probably aid in the digestion of the milk. It has been pointed out that an infusion of coffee possesses antiseptic properties, and that typhoid bacilli and erysipelas bacilli cannot live more than a certain time in it ; and in the case of cholera the bacillus can only resist it for a short period. Septic and Pathogenic Bacteria. J — From an examination of the water which is believed to have caused an outbreak of typhoid fever at Springwater, New York, Mr. G. W. Rafter and Mr. M. L. Mallory have come to the conclusion that septic bacteria are inimical to pathogenic bacteria, and may even be used to destroy them. Contribution to the Study of the Morphology and Development of the Bacteriacese.§ — M. A. Billet confines his remarks to four members of the Bacteriaceae, and more particularly to the zoogloea of Glado- thrix dichotoma , which, on account of its ramified appearance, obtained the name Zoogloea ramigera. The existence of this definite zoogloeic form induced Dr. Billet to search among the other Bacteriaceae for this particular stage, and he was fortunate enough to be able to find a definite * Proc. Roy. Soc. Edinb., xvii. (1889-90) pp. 257-70. t Rev. Mycol., xii. (1890) pp. 199-200. X ‘Report on the Endemic of Typhoid Fever at Springwater, N.Y.,’ 1890, 21 pp. and 3 pis. § Bull. Scient. France et Belg., 1890, 288 pp. See Rev. Mycol., xii. (1890) pp. 187-8. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 81 zooglceic form in three other species — Bacterium osteophyllum and B. Balbiani spp. nn,, and B. parasiticum. Red Bacillus from River Water.* — Prof. A. Lustig describes a bacillus which secretes a red pigment and liquefies gelatin. In plate- cultivations of 8 per cent, pepton-gelatin, colonies developed in 48 hours. In the centre of the colonies the pigment is first observed. In less than three days the pigment had spread to the periphery, and in 4-6 days the whole of the gelatin had become liquid, forming a sticky mass. Culti- vations were also made in agar, potato, blood-serum, bouillon, and milk, in all of which the characteristic raspberry-red pigment was developed. No development took place in distilled water, although the vitality of the organism remained, as was shown by inoculating gelatin after the water had remained unclouded for months. The bacillus grew with the formation of pigment in the absence of oxygen and in presence of hydrogen. The individual elements are 1* 8-3*0 p long, and about half that in breadth. Endogenous spore-formation was never observed, nor could such spores be demonstrated by any method of staining, and reproduction was evidently by arthrospores. The pigment was extracted from potato culti- vations by scraping off the growth, rubbing it up with a few drops of strong acetic acid, and then treating it with ether until all the pigment was dissolved. The ether was then allowed to evaporate spontaneously. The pigment thus obtained was of a violet-red colour, insoluble in water, but soluble in acetic acid, alcohol, benzin, ether, and chloroform, and was of course altered or discharged by the various decolorizing reagents. This bacillus, which was obtained from river water in Piedmont, is believed by the author to be distinct from the red bacillus of Eisenberg, which is aerobic and is said to be endosporous. The red bacillus of Frank is endosporous, and that of Fraeukel developes a red-yellow pigment. New Marine Schizomycete, Streblothricia Bornetii-t — This new genus of Bacteriaceae, described by M. L. Guignard, forms small colour- less zoogloese about the size of a pin’s head, and having a characteristic shape. They are found in clefts of sea-washed rocks ; in their external aspect they bear some resemblance to Nostocaceae, and in their manner of growth to the Rivulariaceae, but possess neither spores nor heterocysts. Within the zoogloea-jelly are radiating filaments about 1 p thick, which at first are straight and closely packed, but afterwards become inter- twined, forming a confused mass. These filaments are made up of approximately isodiametric members with finely granular contents in- closed in a pretty thick membrane. Non-formation of Pigment by Bacillus of Blue Milk.t — Bike Bacillus prodigiosus and pyocyaneus, which, when cultivated under un- favourable circumstances, lose their power of forming their specific * Centralbl. f. Bakteriol. u. Parasitenk., viii. (1890) pp. 33-40. t Comptes Rendus Soc. Biol., xliii. (1890) p. 383. Cf. Centralbl. f. Bakteriol. u. Parasitenk., viii. (1890) p. 465. % Centralbl. f. Bakteriol. u. Parasitenk., viii. (1890) pp. 455-7. 1891. G 82 SUMMARY OF CURRENT RESEARCHES RELATING TO pigment, so the bacillus of blue milk is found to become in similar circumstances incapable of developing its characteristic pigment. Of this defect Dr. P. Behr narrates four examples. The specimens were obtained from cultivations made by competent observers. These four achromatic species were cultivated by the author on various media, such as gelatin, agar, potato, milk, and the results are compared in a series of four tables. This loss of the chromogenic function is possibly only a temporary aberration. Colour and Pathogenic Differences of Staphylococcus pyogenes aureus and S. albus.* — MM. Lannelongue and Achard attack the view expressed bvRodet and Courmont, that Staphylococcus pyogenes aureus is identical with S albus, and that the one easily passes into the other. Although S. aureus , even in fresh cultivations and in oklones, frequently loses its colour, yet this colour can always be obtained again by breeding from a fresh cultivation, while the white can never be thus changed into orange. The pathogenic properties of the two micro-organisms are of different intensity, those of S. aureus being much stronger than those of S. albus. Acid- and Alkali-formation by Bacteria.t — Dr. T. Smith gives details of some interesting experiments corroborative of the influence of sugar in causing the formation of acid in certain bacterial cultiva- tions. Hog cholera bacillus /3 was inoculated on four media: — (1) Pepton bouillon ; (2) pepton bouillon with one drop of 10 per cent, glucose solution ; (3) pepton bouillon with two drops sugar solution ; (4) pepton bouillon with four drops sugar solution. In twenty-four hours (1) was slightly alkaline, (2) and (3) were slightly acid, and (4) strongly acid. After seven days (1), (2), and (3) were alkaline, but (4) remained acid. A similar set of experiments was made with typhoid bacillus. Iu 24 hours all were distinctly acid. After 10 days the sugarless solution had become alkaline, the other three remaining acid. The inference from these observations seems to be that by the judicious addition of small quantities of sugar an increased growth of many alkali-forming bacteria may be induced, the acid derived from the sugar diminishing the alkalinity of the cultivation. Germicidal Action of the Blood in different conditions of the organism.^ — The experiments of A. Rovighi embraced the germicidal property of normal blood, that of definite disease, and that where the condition was merely febrile. Experiments were also made to determine the optimum temperature of germicidal action. By employing Buchner’s method, the following results were obtained. The blood of healthy men possesses the property of completely destroying the typhoid bacillus, while on Staphylococcus pyogenes aureus and Friedlander’s pneumo- bacillus it exerts a transient and less energetic action. In blood taken from pneumonia patients, the germicidal influence * La Semaine Med., 1890, No. 25. See Centralbl. f. Bakteriol. u. Parasitenk., viii. (1890) p. 429. t Centralbl. f. Bakteriol. u. Parasitenk., viii. (1890) pp. 389-91. * Riforma Med., vi. (1890) p. 656. See Centralbl. f. Bakteriol. u. Parasitenk., viii. (1890) p. 561. ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 83 (Friedlander’s pneumo-bacillus, St. 'pyogenes aureus , typhoid bacillus) appears to be considerably diminished or altogether absent. In the blood of severe dyscras as it is retained. The blood of rabbits which had been kept at a temperature of 41°— 42° until they became notably hyperthermic, destroys a larger quantity of typhoid bacilli, bacilli of rabbit septicaemia, and of St. pyogenes aureus than the blood of normal rabbits. The germicidal action of the normal blood of men and rabbits on typhoid bacillus and St. pyogenes aureus is slower and less marked at 12° than at 36°. At 42° for St. pyogenes aureus it appears to vanish quickly. Preservation and Sterilization of Milk.* — The preservation and sterilization of milk, when effectual, are attended, says H. Bitter, with several inconveniences, such as the costliness of the process and the loss of the odour and taste of the fluid ; these difficulties have been removed by the “ Pasteurization ” of milk, the object of which is to sterilize milk at temperatures between 65° and 80°, so that while the bacteria are killed, the taste and odour are but little diminished. An essential part of the process is to cool the fluid, immediately after heating, down to 10°-12 J, since gradual cooling allows the development of any remaining germs between the temperatures of 40° and 20°. Care must also be taken lest re-infection of the milk take place in the cooler, or in the vessels used for transporting the fluid from place to place. The author describes and gives an illustration of the apparatus which he has devised for pasteurizing milk. Nitrification.f — In a second memoir on nitrifying organisms, S. Winogradski gives the results obtained from pure cultivations of the organism isolated by him. This was a colourless elliptical or roundish cell, with a diameter of 1 p, and is termed by the author Nitromonas. This organism, it is found, may grow normally and continue to exert its functions in a medium which contains no trace of any organic carbon compounds. The principal conclusion arrived at is that perfect synthesis of organic material is possible through the action of organic beings, independently of sunlight. Bence it may be said that the life-history of Nitromonas is characterized by the phenomena of constiuction, and in this respect differs from that of other micro-organisms, the functions of which are principally destructive. Destruction of Anthrax Bacilli in the Body of White Rats.J — Dr. G. Frank, in answer to the explanation given by Metschnikoff about the disappearance of anthrax in white rats after inoculation under the skin, or in the anterior chamber of the eye, considers that the general validity of phagocytosis is in no way improved by the experiments or the explanation. Objection is taken to inferences drawn from cover- glass preparations as being misleading owing to the well-known difficulty of determining whether a bacillus is above, beneath, or within a cell in cover-glass or hollow slide preparations. This deficiency should be * Zeitschr. f. Hygiene, viii., No. 2. See Centralbl. f. Bakteriol. u. Parasitenk., viii. (1890; pp. 506-7. f Ann ales de l’lnstitut Pasteur, iv. (1890) p. 257. See Centralbl. f. Bakteriol. u. Parasitenk., viii. (1890) pp. 392-5. X Centralbl. f. Bakteriol. u. Parasitenk., viii. (1890) pp. 298-300. G 2 84 SUMMARY OF CURRENT RESEARCHES RELATING TO corrected by sections made through the inoculation spot at various stages of the disease. Had the inventor of phagocytosis done this, the layer of necrotic tissue which separates the bacilli devoted to destruction from the leucocytes would not have escaped his notice. In other words, they are cut off from the organism by certain morbid anatomical con- ditions produced by the action of the bacilli at the spot in question, the bacilli and the tissue being destroyed by the poison secreted by the micro-organisms. Penetration of Glanders Bacillus through the intact Skin.* — From inunction experiments made with bacillus of glanders on the uninjured skin of guinea-pigs, M. Cornil concludes that the bacilli gain entrance through the hair-follicles, whence they pass to the cutaneous lymph- spaces. The author infers this from observing that the number of bacilli in the central cavity of the follicle is considerably greater than in the circumjacent connective tissue. The number of animals treated by inunction (the bacilli were mixed up with some ointment) was fifteen, out of which two contracted the disease. The histological appearances were those of inflammation of the skin, most marked about the follicles. The bacilli were stained with anilin-fuchsin. Can Bacteria be introduced into the body by being rubbed in through uninjured skin? j* — In order to answer this question, M. S. D. Machnoff selected strong anthrax cultivations on agar, and rubbed them into the skin of guinea-pigs. In three cases the agar cultivation alone was used ; in four others it was mixed with lanolin. The hair on the back was shorn off short, and the mixture rubbed and pressed in with the finger protected with a caoutchouc cap. All the seven animals died of anthrax in about three days, and in none was there any obvious lesion of the skin. In order to meet the objection that the animals had possibly been infected by inhaling or swallowing the anthrax, three guinea-pigs were smeared over with the lanolin cultivation mixture, and all three remained unaffected. Microscopical sections made from the skin cut out before death where the inunction had been practised, failed to show the presence of bacilli except in small numbers in the hair- follicles, and this only after 48 hours of the rubbing. In sections made from skin removed after death, many, though not all, show accumulations of bacilli in the corium, and these seemed to have distinct relation to the hair-follicles and not to the horny layer of the epidermis. From these observations the author concludes that it is possible that bacteria may be introduced into the animal body through the uninjured skin, and that if so their probable path is through the liair-follicles. It would have been more satisfactory had mention been made of the skin-glands, and if sections had been made from those parts of the skin where inunction had not hem practised. Effect of Micro-organisms on the Fowl-embryo. J — Herr M. Lederer, in making experiments as to the transmission of micro-organisms to the * La Semaine Med., 1890, No. 22. See Centralbl. f. Bakteriol. u. Parasitenk., viii (18904 pp. 334-5. f Russkaja Medicina, 1889, No. 39. See Centralbl. f. Bakteriol u. Parasitenk., vii. pp. 441-3. + Mittheil. aus d. Embryol. Institute d. K.K. Univorsitat Wien, 1890, pp. 66-74. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 85 embryo, used freshly fertilized hen’s eggs, which were artifically incu- bated in the usual manner. When development had proceeded for various lengths of time, a small piece of shell and of the shell-membrane was removed, and the embryo inoculated with various micro-organisms ; the aperture thus made was closed again, and sealed down with wax and a cover-glass. The micro-organisms used were saprophytes, e. g. pink yeast, Staphylococcus albus, Micrococcus prodigiosus , Bacterium vio- laceum , and others. About two hundred eggs were inoculated, and in all cases development was stopped, and this result was usually accom- panied by decomposition. The author comes to the conclusion that the transmission of infection to the embryo of birds takes place in a manner different from that observed in Mammalia. Water Bacteria and their Examination.* — Herr A. Lustig has re- cently published a work on the “ diagnosis of water bacteria, with direc- tions for their bacteriological and microscopical examination.” In dealing with these micro-organisms, the author first treats of those pathogenic to man, next those that are noxious to animals, and thirdly those which are harmless ; the series is further subdivided into cocci, bacilli, and spirilla. Although there is a copious literature of water bacteria, yet, as it is much scattered, this work, which brings together the descrip- tions and results of many writers, cannot fail to be useful, more especially as the diagnosis tables are accompanied by practical directions for the bacteriological investigation of water. Action of Products secreted by Pathogenic Microbes.! — The work of M. Bouchard is in the first place a review of what is at present known as to the action of bacterial secreta on micro-organisms and on animal organisms ; and secondly, a record of the author’s own views. It will be sufficient here to allude to the various theories of immunity, which in this book are discussed at length. According to the author, acquired immunity depends on two factors : — first, an increased germicidal influence of the animal fluids ; and secondly, an increased inclination of the cells to act as phagocytes. If, therefore, the leucocytes acquire an increased tolerance for the bacterial virus, and at the same time the germicidal power of the animal fluids is augmented, the organism may then be said to have obtained an acquired immunity for the disease in question. Fraenkel’s Bacteriology.! — The third edition of Fraenkel’s Out- lines of Bacteriology has just appeared. As far as the lines on which it was originally constructed are concerned, it remains the same, differing from its predecessors chiefly in the additional facts which it records. Thus, several kinds of bacteria are described in the special part for the first time, the position of some is altered, e. g. cholera bacilli are now ignored in favour of the term vibrio. This part is further expanded by the additional space given to the bacteriological examination of air and water. * ‘ Diagnostica dei batferi delle acqne con una guida alle ricerche batteriologiche e microscopiche,’ Torino, 1890, 8vo, 121 pp. See Centralbl. f. Bakteriol. u. Para- sitenk., viii. (1890) pp. 594-5. + ‘ Actions des produits secretes par les microbes pathogenes/ Paris, 1890. See Centralbl. f. Bakteriol. u. Parasitenk., viii. (1890) pp. 433-5. X C. Fraenkel, 4 Grundriss der Bakterienkunde,’ 3rd ed., 1890, 515 pp. See Centralbl. f. Bakteriol. u. Parasitenk., viii. (1890) p. 621. 86 SUMMARY OF CURRENT RESEARCHES RELATING TO Bacteriology for Agriculturists.* — With regard to C. Kramer’s Bacteriology, it will be sufficient to say that it is specially intended for the use of those engaged in agricultural pursuits. Only the first part has appeared, and this deals first with the morphology and biology of bacteria, and also with the methods of examining and cultivating them. The remainder deals with the bacteria in the soil, the changes produced in soil by bacteria, the decomposition of manure and other organic substances, the symbiosis of Leguminoste and bacteria, and finally with the diseases induced by bacteria in plants and animals. Baumgarten’s Annual Report on Pathogenic Micro-organisms, including Bacteria, Fungi, and Protozoa.^ — The second half of Baumgarten’s report on pathogenic microbes for the year 1888 has recently appeared. Beyond stating this fact it is scarcely necessary to say more than that it deals with the literature of the subject in the usual exhaustive manner, and will be found indispensable by those working at pathogenic microbes. D anziger.— Tuberculose bei einem Hahn. (Tuberculosis in a Cock.) Allgem. Med. Central zeitung, 1889, No. 88. Dublee, A.— Die Wirkungsweise der Bakterien auf den menschlichen Korper. (The Mo le of Action of Bacteria on the Human Body.) Korrespondenzbl. f. Schweiz. Aerzte , 1890, No, 19, pp. 612-24. Gosto, B., & A. S cl a vo. — Contributo alio studio delle fermentazioni bacteriche. (Contribution to the study of Bacterial Fermentation.) Rv. d’/giene e Sanita Pubbl ., 1890, Nos. 12/13, pp. 449-65. Gunther, C — Einfuhrung in das Studium der Bakteriologie mit bcsonderer Beriicksichtigung der mikroskopischen Technik. (Introduction to the study of Bacteriology, with special reference to Microscopical Technique.) Leipzig, 1890, large 8vo, ix. and 244 pp. Hunt, E. M. — Micro-organisms and Leucocytes : cur present status as to each. Med. Record , XI. (1890) No. 14, pp. 376-8. Krueger, R. — Beitrag zum Vorkommen pyogener Kokken in der Milch. (On the presence of Micrococcus pyogenes in Milk.) Centralbl. f. Bakteriol. u. Parasitenk., VII. p. 590. Kruse, W. — Ueber Blutparasiten. (The Parasites of the Blood.) Virchow’s Archiv, CXX. p. 541 ; first communication. Laurent, E. — Etude sur la variability du bacille rouge de Kiel. (Study on the Variability of the Red Bacillus of Kiel.) Ann d. de VInstitut Pasteur , 1890, pp. 465 -83. Lubarsch, O. — Ueber die Ursachen der Immunitat. (On the Causes of Immunity.) Furtschr. d. Med., 1890, pp. 665-72. Marmorek.— Bakteriol ogischer Beitrag zur Kenntniss der Influenza. (Contri- bution to the Bacteriology of Influenza.) Wiener Klin. Wochenschr., 1890, Nos. 8 & 9. Ruffe r, M. A. — Notes on the Destruction of Micro-organisms by Amoeboid Cells. Brit. Med. Journ., 1890, No. 1548, pp. 491-3. Sc h ron, v. — Zur Genese der Mikroorganismen. (The Development of Micro- organisms.) Allgem. Wiener Medic. Wochenschr., 1690, pp 435-6. Stern, R.— Ueber die Wirkung des menschlichen Blutes und anderer Korper- fliissigkeiten auf pathogene Mikro-organismen. (On the Action of Human Blood and other body-fluids on Pathogenic Micro-organisms.) Zeitschr. f. Klin. Med., XVIII. (1890) pp. 46-71. * Wien, 1890, 8vo, 171 pp. See Centralbl. f. Bakteriol. u. Parasitenk., viii. (1890) pp. 462-5. f ‘ Jahresbericht fiber die Fortschritte in der Lehre von den Pathogenen Mikro- organismen, umfassend Bakterien, Pilze und Protozoen,’ Braunschweig, 1890, Jahrg. iv. (1888) 2te H'alfte, pp. 257-587. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 87 MICROSCOPY. a. Instruments, Accessories, &c.* (1) Stands. Report of the Committee of the American Society of Microscopists on Uniformity of Tub e-length, f — The following Report has been issued by the American Society of Microscopists : — “ Believing in the desirability of a uniform tube-length we unanimously recommend : — (1) That the parts of the Microscope included in the tube-length should be the same by all opticians, and that the parts included should be those between the upper end of the tube where the ocular is inserted and the lower end of the tube where the objective is inserted. (2) That the actual extent of tube-length as defined in section 1 — Be, for the short or Continental tube, 160 mm. or 6*3 in., and 8J in. or 216 mm. for the long tube, and that the draw-tube of the Microscope possess two special marks indicating these standard lengths. (3) That oculars be made par-focal, and that the par-focal plane be coincident with that of the upper end of the tube. (4) That the mounting of all objectives of 1/4 in. and shorter focus should be such as to bring the optical centre of the objective 1J in. below the shoulder ; and that all objectives be marked with the tube- length for which they are corrected. (5) That non-adjustable objectives be corrected for cover-glass from 15/100 to 20/100 mm. (1/130 to 1/170 in.) in thickness. These recommendations give a distance of 10 in. (251 mm.) between the par-focal plane of the ocular and the optical centre of the objective for the long tube, and are essentially in accord with the actual practice of opticians. At the request of the committee, a joint conference was held with the opticians belonging to the society and present at the meeting. They expressed their belief in the entire practicability of the above recommendations, and a willingness to adopt them. — Signed, Simon H. Gage, A. Clifford Mercer, Prof. Barr.” Swift and Son’s Improved Student’s Microscope —At the October meeting of the Society, Mr. G. C. Karop exhibited and described this instrument (fig. 1), which he said had been brought out by Messrs. Swift at his suggestion. The aim was to produce a Student’s Microscope of a superior design, with which high-class optical appliances could be used. The body-tube is made to take the full-size eye-pieces in general use, and short enough to work with objectives adjusted to the Continental tube-length. A draw-tube lengthens to the English standard of 10 in. The bearing carrying the body is made longer than usual in students’ instruments, so as to give greater firmness with low-power objectives. The fine-adjustment was that known as Campbell’s Differential Screw * This subdivision contains (1) Stands; (2) Eye-pieces and Objectives; (3) Illu- minating and other Apparatus ; (4) Photomicrography ; (5) Microscopical Optics and Manipulation ; (6) Miscellaneous. f Microscope, x. (1890) p. 297. SUMMARY OF CURRENT RESEARCHES RELATING TO 88 system, and is arranged for very delicate focusing. Both the coarse and fine adjustments are provided with extra large milled heads to afford a firm grasp. The stage is of the Nelson horse-shoe shape, and Fig. 1. large enough to take culture-plates ; this form is adopted for lightness and for the facility it gives in feeling the working distance of the objective. Instead of the usual spring clips, a sliding frame is provided ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 89 with sprung guides moving in grooves at the sides of the stage ; small clips are applied for use in the horizontal position. The Mayall mechanical stage can be applied if required. The sliding-bar carrying the substage is specially wtdl fitted so that a condenser of fairly largo aperture may be focused, and a clamping screw fixes it in position. The substage has mechanical centering movements, and an iris-diaphragm. The mirror is removable in case it may be desired to work with direct light from the lamp. We are requested by Messrs. Swift to note that at a small additional cost they can apply a rack-and-pinion instead of the sliding movement to the substage. Mason’s Improvements in Oxy-hydrogen Microscopes.*— Mr. R. G. Mason, of 69, Clapham Park Road, Clapham, S.W., has introduced the above form of lantern and table Microscope, a patent for which has been applied for. Until the present time the lantern Microscope has been a distinct instrument from the table form of stand. By the union of the above parts an instrument is obtained that, when not in use for Fw. 2. Fig. 3. screen projections, can be easily altered, as shown by fig. 3. No unscrewing is required, and there are no loose parts. Fig. 2 shows the instrument as used on the lantern. It is very convenient for the science teacher or general lecturer, as a demonstration may be made to either a small or large audience with equal facility. The lower part, which carries the joint for inclining the instrument at any angle, is fitted with concave and flat mirrors on swinging arm, also with the universal size substage fitting tube for apparatus. The body and draw, which fits into the upper part, is of large diameter, and is screwed with the Society’s size screw, thus enabling any ordinary microscopic objective to be used with it. It is fitted with a first-class rack, and also screw fine motion working steadily under high powers. This fine motion is especially useful in photo- micrography. The stage being of the usual form, both object and objective are in view, and easily manipulated while in use, thus doing away with an objection that is often present in the older formsjof lantern * Engl. Mech., lii. (1890) pp. 306-7. 90 SUMMARY OF CURRENT RESEARCHES RELATING TO Microscope. A further improvement is a spring clip, enabling the object to be easily changed without scratching the labels, &c., its con- struction admitting of either a deep zoophyte trough or the thinnest 3x1 slip being held gently but firmly. The parts are supplied separately, so that auy one needing only the lantern arrangement can add the other at any future time. (3) Illuminating and other Apparatus. The Substage Condenser: its History, Construction, and Manage- ment ; and its effect theoretically considered.* — Mr. E. M. Nelson remarks — “ The substage condenser is nearly as old as the compound Microscope itself. The first microscopical objects were opaque, and in very early times a lens was employed to condense light upon them. It was an easy step to place the lens below the stage when transparent objects were examined. Coming to more modern times we find that the culminating type of non-achromatic Microscope was fitted with a substage condenser, but it had a very brief existence, not being able to hold its own against the recently introduced achromatic. Had the invention of achromatism been delayed, it would, I have no doubt, have had enormous popularity for those times. I allude to the Wollaston doublet with its substage condensing lens, particularly that form designed by Mr. Valentine and made by Andrew boss in 1831. Before proceeding we must remember by whom the Microscope was used at that time. As far as this country was concerned, it was merely looked upon as a philosophical toy. It was principally to be found in the hands of a few dilettanti ; science of every kind was tabooed, the Microscope being placed at the lowest end of the scale. Now. the Microscope of the dilettanti is usually a perfect instrument of its kind, fully supplied with apparatus, the greater part of which is absolutely useless, but among this apparatus there would always have been a substage condenser. One of the principal things the dilettanti have done for ns is the keeping up through early achromatic days of the continuity of the condenser. On the Continent, where science held a much more important place, the real value of the Microscope was better understood, and it at once took an important place in the medical schools. But the increase of light due to the more perfect concentration of rays by achromatism enabled objects to be sufficiently illuminated by the concave mirror to meet their purposes. Therefore, we find that on the Continent the Microscope had no condenser. Of course there were isolated excep- tions, Amici’s for example ; but T think we may safely say that for every Hartnack made with a substage condenser there were upwards of one thousand made without. England followed the Continental lead, and now the “foolish philosophical toy ” has entirely displaced in our medical schools the dog-Latin text-book with its ordo verborum. But the kind of Microscope adopted was not that of the English dilettanti, but the condenserless Continental. It may be said that the Microscope for forty years — that * Joum. Quek. Micr. Club, iv. (1890) pp. 116-36. For the use of the accompany- ing plate we are indebted to the kindness of Mr. Nelson and the Quekett Micro- scopical Club. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 91 is, from the time it was established in the schools in, say, 1840 to 1880, has been without a condenser. Not only did those who used the con- denserless Microscope consider the condenser an unnecessary appendage, but they looked down upon it and regarded it in the same category as one of the multitudinous appliances that are packed in such a wonderful manner in the apparatus cabinet of a Microscope made for exhibition. In 1880 a change came from two separate causes — first, the rise of bacteriology : secondly, the introduction of a cheap chromatic condenser by Abbe in 1873. Taken by itself, the introduction of the Abbe condenser had not much effect, but as Zeiss’s Microscopes had for some time been dis- placing the older forms, and when the study of bacteriology arose, oil-immersion objectives of greater aperture than the old dry objectives (especially those of the histological series) were used, illumination by the mirror was soon discovered to be inefficient, so a condenser became a necessity. The cheap Abbe condenser was the exact thing to meet the case. Since 1880 the percentage of educational Microscopes, medical or otherwise, without condensers, has been daily on the decrease. There has not been, during the 'past history of the Microscope, a more marked change of opinion with regard to any apparatus than that which has taken place in connection with the condenser. It is worthy of notice that this change of opinion has been so complete that those who formerly condemned all condensers now look upon the Abbe chromatic (probably the worst condenser ever con- structed) as a distinct advance in microscopy ! It must be remembered that the end of an educational Microscope is not to discover anything new, but to follow the figures given in the text-books, and when the text-books kept on the level of the larger objects any tube with a piece of glass at either end was sufficient for the purpose ; but as the text-books improved and went deeper into the structure of things it was necessary that the student’s Microscope should be of a better description. For example, as long as the text- books wrote about and figured the spiral vessels in the blowfly’s tongue, so long the student did not require a Microscope capable of showing the cut suctorial tubes. As I mentioned above, the “few,” principally dilettanti, had all along used a condenser. I myself had not long entered the micro- scopical world as a member of the latter class before I found out that a condenser was a necessity. Now, as I have used all the kinds of condensers that have been introduced, I will give my own history in connection with them, as it will be the history of the condenser. My first condenser was a Gillett ; this was in power a 1 /4, and it had 80° of aperture. The Gillett is practically the first achromatie condenser really constructed as such ; before that time • objectives were used, the rule being to select that objective which was next lower in power to the objective on the nose-piece. The manner of centering — for centering was duly insisted upon even in those early times — was. so funny that I must recall it. Vertical movement was performed by the substage, but the horizontal movement by the Microscope body ! The Gillett was an elaborate instrument ; it was supplied with a 92 SUMMARY OF CURRENT RESEARCHES RELATING TO correctional lens adjustment for the aberrations arising from the thick- ness of the slip. I have a distinct affection for the Gillctt, for it was with that condenser I taught myself what a critical image was. In 1874, however, I purchased a P. and L. new formula water-imm. 1/8 of N.A. 1 • 21. These and similar lenses by Tolies far surpassed any- thing at that day. There was a greater difference between these lenses and their cotemporaries than there was between the homogeneous immersion and these same lenses four years later. I can only liken the improvement which those lenses ushered in to that which has lately been achieved by Abbe’s apochromatics. It was the possession of this lens (P. and L. new formula 1/8) that first made the inadequacy of the Gillett apparent to me. This led me to get P. and L. dry achromatic condenser, which I still have. This condenser was designed by Powell in 1857 ; it is a 1/5 in power, and *99 N.A. in aperture, and is the best ever introduced. I must now say a word or two on low power condensers. Low power objectives had, somehow or other, been left out in the cold, no condenser having been provided for them. A sop, in the shape of a paraboloid or spot lens, was every now and then thrown to them, but, as far as I know, the first low power condenser we hear of is Webster’s, in 1860. The next was Abbe’s chromatic,* 1873; Swift’s achromatic, 1874; Abbe’s achromatic, 1888, and Powell’s new one, last year. On the Continent the Microscope may be said to have remained condenserless until the rise of bacteriology compelled the general adoption of the Abbe in 1880. I will now give a parallel table showing the data and form of various condensers that have been introduced since the days of achromatism : — England. 1826. Single lens, Tulley. 1840. Objective. 1850. Gillett, three pairs, N.A. '65. 1857. Powell, two pairs and single, an- terior middle concave, N.A. •99. 1865. Webster, single front, achromatic back. 1874. Swift, two pairs and single front, N.A. -9. 1878. P. and L. achromatic, improved anterior middle plane, * 99 N.A. 1881. P. and L. oil chromatic, same as Abbe only higher power, N.A. 1*3. Ditto, truncated, N.A. 1 -4. 1887. P. and L. oil achromatic, N.A. 1’4, three pairs and single front. 1889. P. and L. low power achromatic, N.A. 1*0, one pair and two singles. * Abbe’s chromatic stopped down makes a far better low power condenser than it does a high power, as the stop reduces the abnormal amount of spherical aberra- tion. Continent. 1827. Single lens, Amici. 1833. Chromatic, Chevalier I 1839. Objective, Dujardin i 1873. Abbe, chromatic, N.A. 12, hemi- spherical front, crossed back. (? date) Another form, N.A. 14, single front, Herschelian doublet back. 1888. Abbe achromatic, two pairs and a single front, N.A. 1 ‘0. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 93 This table shows that here, at least, there was an activity with regard to the condenser that was totally absent abroad. It must, moreover, be remembered that the list gives only types of condensers: Ross, for instance, made improvements on the Gillett, and Smith and Beck made numerous forms of condensers which have not been mentioned, simply because they were not typical. Messrs. Crouch and Collins made numerous condensers, mostly after the Webster type. So also, on the other side, Nachet and Hartnack fitted object-glasses as condensers, only to a much more limited extent. My impression is that, if statistical tables were available, it would be found that up to 1880 there were more condensers turned out by any one well-known English maker than by all the Continental firms put together. We now come to the use of the condenser, and the first question that arises is with regard to the nature of the source of light : Is daylight or lamplight to be used ? I find with low and medium powers, the condenser being centered to the optic axis, the plane mirror used, and a window-bar focused on the object, that daylight gives very good results, especially if a brightly illuminated white cloud is the illuminating source ; but when the white cloud has blown across the field, leaving only blue sky, the illumination becomes poor. My complaint against daylight illumination for low power work is that I believe it not only to be always changing, but also very injurious to the eyesight. When I began Microscopic work the white cloud was everything, but on account of the above-mentioned drawbacks I adopted artificial illumination. The most extraordinary ideas prevailed respecting artificial illumination. The history is as follows : — Brewster wrote a treatise on the Microscope in 1837, and in it explained his method of illumination. He was very keen on monochro- matic illumination ; this he obtained from some chemical substances flaming in a saucer, without any wick or chimney ; light from this was parallelized by a bull’s-eye formed by a Herschelian doublet, and this brought to a focus by another exactly similar lens. He is very particular to enforce that the image of a diaphragm placed between the source of illumination and the bull’s-eye should be focused on the object. This was in preachromatic days, and the kind of Microscope he experimented upon was the simple Microscope, the lenses being jewel singles, doublets, triplets, Coddingtons, which last were his own invention, &c. With such a source of illumination, unless his object had been in rays considerably condensed, he would not have seen anything at all. Be that as it may, the fact is that the rule of having the source of light in focus has been handed down by the text-books all along, only with this curious proviso, viz. that each author had his own particular directions for disregarding the rule. Taking Andrew Ross first, whose directions are considered so admir- able that Quekett says he will quote them at length, we find that after he has given instructions with regard to centering, he says that delicate objects are best seen by racking the condenser within, and objects having some little thickness without the focus. Further on he says that slight obliquity of the illumination subdues the glare attendant upon perfectly central and full illumination by lamplight ; he then goes on to say how this slight obliquity may be secured. The above words 94 SUMMARY OF CURRENT RESEARCHES RELATING TO form the keynote for artificial illumination in every subsequent text- book. They are repeated by Carpenter, who, after giving directions as to centering and focusing the image of the lamp-flame on the object, says that “ the direction of the mirror should then be sufficiently changed to displace the image and to substitute for it the clearest light that can be obtained.” Further, he recommends that while with day- light the condenser should be used in focus, with lamplight it should be somewhat racked down. From this I gather that Dr. Carpenter’s best artificial illumination is oblique light out of focus. Of course the actual fact is that daylight focus is not nearly so important as lamplight. In illustration of another kind of mistake, as late as ten years ago it wras recommended that the diaphragm be placed above the condenser as giving a better result than when placed below. Of course the optical effect is precisely the same, the only thing is that the diaphragm below the condenser is much more readily manipu- lated and is much more likely to be accurate in centering, unless the one above be of the cap form. To change a cap diaphragm necessitates either the removal of the slide or the condenser, and all for no purpose. The next idea was worse, viz. the calotte diaphragm. This being fixed to the stage and not to the substage, gave as often as not excentric pencils. Whatever diaphragm is used it obviously must be centered to the condenser and must move with it, otherwise it will be put out of centre during the operation of centering the condenser to the optic axis of the objective. Further, the calotte diaphragm is useless for ordinary illumination without a condenser, as the apex is not the proper place to cut the illuminating cone. The proper place, therefore, for a diaphragm, when no condenser is used, is some distance from the object, and when a condenser is used, is at the back of the combination. Further, when a diaphragm is above the condenser the apertures become almost microscopic in size, and a very small difference between them will make a con- siderable difference in their effect ; but when they are placed behind the combination they may be larger, and it becomes more easy to graduate them in accordance to any desired effect. Again, it is a fallacy to suppose that a Kelner eye-piece is superior to a condenser as an illuminator for high powers. A Kelner eye-piece, if a C, is only 1 in. in power, and has a small angular aperture somewhat less than 45°, therefore it cannot possibly give a cone at all comparable with that from a most elementary con- denser. It might be used as a substage condenser for low powers, but from its small aperture it would hardly give a good dark-ground illumi- nation for a 1-in. objective. With regard to low power condensers, the Webster (as designed by Webster) is the proper form. There are many so-called Webster con- densers in existence which are on a totally wrong principle. The right kind of Webster has a single front lens and a back lens composed of a plano-concave flint and a crossed convex crown, the cemented surfaces having a deep curve to overcorrect the lens. The other kind, which is quite wrong, has an achromatized front and a single back ; it is merely done for cheapness, as small achromatic pairs are not so expensive as large ones, and the back lens of a condenser is always larger than the front. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 1)5 Another mistake is that direct light is more critical than indirect, which means, in other words, that illumination without a mirror is more critical thau illumination with a mirror. Presupposing the same con- ditions, viz. the same condenser with the same stop, the centering and focus being precise, the optical conditions must be identical and the result the same. The ground is entirely cut away from the one only thing which could possibly atfect the result — I allude to the loss of light by reflection at the mirror, by the fact that you have, with merely a 1/2- in. paraffin wick, more light than you know what to do with. So much is this the case that in my own practice I am in the habit of using a double cobalt pot-glass screen to reduce the intensity. 1 am aware that direct illumination is a most convenient and time- saving method, especially when the instrument is well tucked up on its trunnions, but that it makes any perceptible difference in the criticalness of the image I am not prepared to admit. With regard to mirrors, a good deal of misapprehension exists. It matters little whether the mirror be dusty or scratched, or the silver in bad condition ; the only effect these will have will be to cause a little less light to fall on the back lens of the condenser, a matter supremely unimportant. An old scratched dull mirror will yield as critical an image as the finest worked up silver on glass Newtonian flat. The three things that are of paramount importance are the direction of the light, the angle of the cone, and the spherical aberration of the condenser. Mirrors which yield secondary reflections are to be avoided, but if they can be turned round in their cells the secondary images can be easily eliminated. Having touched upon the errors in the use of the substage condenser, let me say a few words with a view of clearing up some strange notions that are held with regard to its office. The original prevailing idea with regard to the office of a substage condenser was, I believe, in the first instance, that of a contrivance by which more light could be secured ; afterwards it became chiefly important as an oblique illumi- nator ; but its true function as that of a cone-producer was not generally recognized. As this view of mine will probably be met by the criticism that in the text-books, both ancient and modern, we read “ that the condenser must be accurately focused,” that the use of the diaphragm is for the purpose of contracting the cone of illumination ” (many similar passages might be quoted), I nevertheless contend that there are other passages which conclusively prove that the writers were ignorant of the true function of the condenser. The following is an example : — “ If the cone of rays should come to a focus in the object, the field is not unlikely to be crossed (in the daytime) by the images of window-bars or chimneys, or (at night) the form of the lamp-flame may be distinguished upon it ; the former must be got rid of by a slight change in the inclination of the mirror ; and if the latter cannot be dissipated in the same way, the lamp should be brought a little nearer.” This passage proves that the end-all and be-all in the writer’s mind was the agreeableness of the illumination ; when the glare of the lamp- flame becomes unpleasant, the cone may go to the wall. If the importance of the cone had been paramount in the mind of 96 SC MM ARY OF CURRENT RESEARCHES RELATING TO the writer, lie would have certainly suggested the obvious method of softening down the intensity of the flame-image by interposing coloured screens. Taking the whole tenor of the passage, there caunot be the bast doubt that the ends sought for were suitable intensity of light and equable illumination of field ; the frequent mention of the word cone being more accidental than insisted on for the sake of the cone itself. It is as a cone-producer wherein the efficacy of the condenser lies. If, as is implied in the text-books, it were only light-intensity which gave criticalness to the image, that could be secured by exchanging the light from the 1/2-in. paraffin wick for that from the electric arc, but such an exchange would cause no alteration in the character of the image so long as the aperture of the cone remained the same. The real office of the substage condenser being a cone-producer, the first question that arises is, What ought to be the angle of the cone ? This is really the most important question that can be raised with regard to microscopical manipulation. To this I reply that a 3/4 cone is the perfection of illumination for the Microscope of the present day.* By this I mean that the cone from the condenser should be of such a size as to fill 3/4 of the back of the objective with light, thus N.A. 1*0 is a suitable illuminating cone for an objective of 1 * 4= N.A. (dark grounds are not at present under consideration). This opinion is in direct opposition to that of Prof. Abbe in his last paper on the subject in the December number of the B. M. S. Journal for 1889, where he says : — t; The resulting image produced by means of a broad illuminating beam is always a mixture of a multitude of partial images, which are more or less different (and dissimilar to the object itself). There is not the least rational ground — nor any experimental proof — for the expectation that this mixture should come nearer to a strictly correct projection of the object (be less dissimilar to the latter) than that image which is projected by means of a narrow axial illuminating pencil.’- f This paper I consider to be the most dangerous paper ever published, and unless a warning is sounded it will inevitably lead to erroneous manipulation, which is inseparably connected with erroneous interpre- tation of structure. If you intend to carry out his views and use narrow-angled cones, you do not need a condenser at all — more than this, a condenser is absolutely injurious, because it affords you the possibility of using a large cone, which, according to Prof. Abbe, yields an image dissimilar to the object. If there is the slightest foundation for Prof. Abbe’s conclusion, then a condenser is to be avoided, and when a mirror is used with low powers care must be exercised to cut the cone well down by the diaphragm. In the opening sentence of the paper Prof. Abbe says, “ The diffraction theory leads to the following conclusions in regard to the mode of illumination in question.” We are, therefore, thrown back on the diffraction theory, for the discussion of which I must ask your kind * Mr. Comber (R. M. S., May 21st, 1890) states that in practice he finds a 2/3 cone best for photomicrography. A 2/3 cone (photographically) is to a 3/4 cone (visually) as 10/12 is to 9/12. Mr. Comber’s experience is therefore in accordance with this statement. t R.M.S. Journal, 1889, Part 6, p. 723. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 97 indulgence, as the only other avenue for such a purpose has been closed to those who do not accept Prof. Abbe’s theory in its entirety. The diffraction theory has been likened, as you are aware, to tlio theory of gravitation. Let us, therefore, compare them. The theory of gravitation may be said to rest on three points — viz. mathematical proof, physical law, and experimental proof ; — moreover, it is not afraid of criticism. The diffraction theory rests on no mathematical proof — in the main it accepts the physical law of diffraction ; but on experiment it utterly breaks down, all criticism is stopped, and everything connected with it has to be treated in a diplomatic kind of way. Both theories may be said to resemble an arch, being built up on theory and experiment, and held in equipoise by a keystone at the top. The diffraction arch, after being built up on theory and experiment, culminates with the calculation of the Eichorn intercostals as its key- stone. The discovery of these intercostals on the P. angulatum (which has been likened to the discovery of the planet Neptune) was arrived at by “ a mathematical student, who had never seen a diatom, and who worked the purely mathematical result of the interference of the six spectra.” In the same way the discovery of Neptune may be called a key- stone of the gravitation theory. It would be incorrect in this connection to say the keystone, because the gravitation theory has many keystones, while the diffraction theory has only the one, viz. the Eichorn inter- costals. If, for instance, one could prove that the planet Neptune had no objective reality, but was a mere optical ghost, the gravitation theory would be seriously compromised. If, this evening, I can prove that the Eichorn intercostals are ghosts, then I maintain that I have taken the only keystone from the diffraction theory arch, and the conclu- sions which Prof. Abbe has arrived at in consequence of that theory, with regard to illumination by means of the wide-angled cone, are fallacious. Let me at this place state that I wish it to be distinctly understood that I am not, in this paper, attacking Prof. Abbe’s brilliant dis- covery that the image in the Microscope is caused by the reunion of rays which have been scattered by diffraction, neither do I question what I venture to think is his far more brilliant experiment, which exhibits the duplication of structure, when the spectra of the second order are admitted, while those of the first are stopped out. I regard these facts as fundamental truths of microscopy. The thanks of all true micro- scopists are due to Prof. Abbe for giving them to us. It will be then asked, how can you disagree with that which you admit ? The point is, that it is in the meaning of the word “ diffraction image ” that tho difficulty lies. Let me explain. There are in reality three kinds of diffraction images, for which I will now substitute the following names, “ true diffraction image,” “ true diffraction ghost,” and “ false diffraction ghost,” in place of those I used in my previous paper.* Now I maintain that both Prof. Abbe and his exponents at the R.M.S. have fallen into the grievous error of not distinguishing between these * Q.M.J., Ser. II., vol. iv., No. 25, p. 17, “true, true false, and false.3 1891. H 98 SUMMARY OF CURRENT RESEARCHES RELATING TO three images, viz. the true diffraction image, and the true and false diffraction ghosts. You will naturally ask, how do jmu distinguish between these three images ? A true diffraction image goes in and out of focus like a daisy under a 4 in. In other words, a true diffraction image is one out of which it is impossible to make another image by focal adjustment. A diffraction ghost, on the other hand, is one which changes into other images on focal adjustment, a false diffraction ghost being an image which is dissimilar to the original, and a true diffraction ghost one in which it is fairly in accordance with the original. A true diffraction image is produced by a large cone of illumination, except in those cases where the structure is so fine, in relation to the aperture of the objective, that the large cone does not cause the spectra to overlap one another and the dioptric beam. True and false diffraction ghosts are produced by small cones, except in those cases where the structure is either so coarse that the spectra overlap, even with the small cone, or so fine that only spectra of the first order are taken up by the objective ; in this latter case a false diffraction ghost becomes impossible. Taking the ghosts first, the reason why there is a change of image on alteration of focus may be seen on reference to plate II. fig. 3. Let 0 be an object having about 20,000 interference elements per inch, let DD be an infinit-ely thin diop- tric beam in the optic axis, then S and M will be the spectra of the first order, and T and X those of the second. If the object be examined by an objective whose aperture is greater than the angle T 0 N, i. e. upwards of 100°, a diffraction ghost will be seen, because at the longer focus the spectra S and M will be united with D, and a representation similar to the true structure will be produced ; but on shortening the focus the spectra T and X will be united with D, and a picture having double the fineness of the original structure will be seen. (You require no stop at the back of your objective to perform this experiment ; the spherical aberration, which is always present, even in the best corrected lenses, will be sufficient to prevent the union of S and M with T and N. See Mr. Leroy’s results on applying the Foucault test to Microscope objectives, E.M.S.J., 1890, p. 224: the spherical aberration varied from tenths of mm. to several mm.) It is therefore a diffraction ghost, because the image alters on focal adjustment ; it is a true ghost at the upper focus and a false ghost at the lower focus. Let us now see what takes place when a large cone is used. Let PP be an isolated pencil of such a cone, then HQ will be spectra of the first order, and R a spectrum of the second, and K one of the third order. These dotted lines are drawn at a little distance from the others for the sake of clearness, but they are supposed to be either coincident with or very near the others. Here we see at the upper focus that a spectrum of the second order R is combined with a dioptric beam P, and a first diffraction spectrum Q, and this takes place in addition to the combination of S and M with D mentioned above. Bringing in a diffraction spectrum of the second order will tend to improve the image. At the lower focus even now there will be a first diffraction spectrum H, combined with a third order spectrum K, together with the combination of H and X with D as above. This combination ■would give a confusion of images, so it comes to pass that images with ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 99 a wide angled cone at the lower focus aro blotted out. To state the combinations more concisely at the upper focus, we have two first order spectra and a dioptric beam ; and a first and second order spectrum and a dioptric beam. At the lower focus you have two second order spectra and a dioptric beam ; and two first orders and a third order. It may be as well to explain to those not acquainted with optics, that these combinations are caused by the spectra T N and H U passing through the same zone of the objective. The union of a set of spectra such as S D M makes a certain kind of image, and the union of P Q R will make a very similar image, not absolutely similar, but so similar that it would be difficult to tell the difference between them. So it comes to pass that the superposition of a number of very similar images strengthens the picture and gives a resultant image very close to the original structure. But the image caused by the union of T D N is totally dissimilar to the original, and HQK would also be very dis- similar and the superposition of a number of these can only make a stronger dissimilar picture, or if the pictures, which are superposed, differ widely from one another, then the superposition of them will pro- duce a fog. By way of illustration, suppose I made a large number of photomicrographic lantern slides, using certain spectra, which gave an image closely resembling an original known structure, and suppose each lantern slide to be a picture, resulting from a different narrow dioptric beam, such as D and P in our diagram, and others lying between them, we should then have a number of lantern slides, all very similar to the original and consequently to one another. Now suppose we had a number of lanterns and projected these several images at once on the screen, the several images would combine to form a strong image closely resembling the original structure. If, however, we make other lantern slides, using spectra, such as T N, which double the original structure, and if these are projected on the screen in place of the others, we shall get a strong image of a structure altogether dissimilar to the original. But if we increase the number of our lanterns, and project the other images as well, we shall have a confused image on the screen, or fog. Another illustration may help to simplify the matter. Suppose it were possible in photographing a dog with an ordinary camera, by manipulations at the back of the objective, to obtain, either an image only very slightly dissimilar to the real dog (such as an image slightly out of focus), or with other manipulations to obtain a picture of a hayrick. If a number of these slightly dissimilar images of the dog were projected on the screen, we should still have the image of a dog, and one that we could readily recognize. But if we projected the images of the hayrick, we should not have the slightest idea that the original object was a dog, and further, if the images of the hayrick were projected at the same time as those of the dog, the result would be a confused mass of light in which it would be impossible to recognize any image. Whether any particular lantern slide turn out a dog or a hay-rick, depends on the physical union of various other oscillations, but whether the image of either the dog or hayrick be a strong one, or a mass of fog, depends on the mechanical combination of similar or dissimilar images. H 2 100 SUMMARY OF CURRENT RESEARCHES RELATING TO W e must now return to the Eiehorn intercostals ; the history re- garding these is as follows : — The six spectra of the first order of P. angulatum (fig. 1) were set to a student who had never seen a diatom, and he calculated the pre- sence of an intercostal. These intercostals were afterwards seen hy Mr. Stephenson, and the student’s discovery was likened to that of Neptune. There is a double error here. The first is that the inter- costal is a function of the spectra of the second order, and can neither be calculated, originated, nor seen by those of the first order. Secondly, the intercostal is not a true diffraction image, but is a false diffraction ghost, and is caused by the reunion of the spectra of the second order, and the exclusion of the first order. The very data given to the student have to be excluded before an intercostal can appear or be calculated ! The error in connection with the exhibition of the intercostals of the P. angulatum is that no sufficient checks were imposed to render it absolutely certain that no spectra of the second order were present at the time the intercostals were seen. The intercostals have also been accounted for by a fallacious geometrical picture. Thus, the six spectra (fig. 1) account for three sets of lines ruled at 60° to each other. Now, as I pointed out in the ‘ English Mechanic,’ v »1. xliii., No. 1108, p. 337, two very different pictures are produced according to whether the third line be ruled through the apices of the rhombs (fig. 4) or not. It is for those who uphold the truth of the intercostals to show which spectrum or what arrangement of the six spectra determines that the third line does not pass through the apices of the rhombs (fig. 6). The contrary is really the fact, viz. that if there is any truth at all in the diffraction theory, then with a spectral arrangement as set to the mathematical student the third line must pass through the apices of the rhombs (fig. 5). Figs. 4, 5, and 6 show the rhombs and the formation of the two kinds of pictures. In passing, it is as well to note that objectives being for the most part spherically undercorrected, generally show the intercostals at the lower focus. In other words, you have to lower your objective in order to obtain the reunion of the spectra of the second order by means of the outer zone of the objective. Intercostals are due to illumination by means of a narrow cone, which allows and aids zonal differences to operate on the spectra, uniting those of the second order, whilst excluding those of the first. Illumination by a large cone neutralizes the effect of these zonal differences, and intercostals disappear. I have given much attention to diffraction ghosts, and have made several photographs of them for your inspection. Instead of confining my investigations to P. angulatum, as has been usually done, I thought ft better to select very coarse structures, concerning the true appearance of which all microscopists are entirely agreed. In the first instance, I experimented with the coarse hexagonal structure of a Triceratium, which measured 1/3600 in. A photograph x 387 taken with a large cone I will now project (fig. 7). The illuminating cone was now cut down by closing the iris diaphragm, and the aperture of the objective stopped down until the spectra at the back of the objective appeared as in fig. 2. The next photograph (fig. 8) shows the image due to those ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 101 spectra ; this shows the intercostals, and is what I term a false diffrac- tion ghost. You will observe that the objective has been placed at a lower focus. If the same, i. e. the upper focus, had been used, then a picture similar to the true image taken with the large cone would bo seen, except that the walls of the hexagons would be considerably thicker, and in the centre of each areolation there would be a dark spot. If the illuminating cone be enlarged to a 3/4 cone the image will closely resemble the critical image (fig. 7) already shown, and more- over will be a true diffraction image, because it will go in and out of focus as a daisy under a 4-in. In examining the various images pre- sented by a hexagonal grating in focal alteration, when a small cone of illumination is used, I found that these false diffraction ghosts followed a certain sequence, and might be grouped in three classes, which I term degrees. The false diffraction ghost of the first degree requires spectra of the second order (fig. 2), for its production. It is the Eichorn intercostal image. The next experiment was performed with the narrow cone as before, but with the aperture of the objective reduced so that the second order of spectra (fig. 1), were cut out ; according to my theory no inter- costals should now be visible ; on taking the photograph, however, a trace of them could be distinguished (fig. 9). This is such an interesting result that I have printed the negative. The fact was that I had cut out the second order spectra visually but not photographically. On further cutting down the aperture quite up to the end of the spectra of the first order, no intercostals could either be seen or photographed (fig. 10). This is an additional proof that the intercostal image is a func- tion of the spectra of the second order. Further, if an intercostal on P. angiilatum is resolvable by means of spectra of the first order, which diverge about *5 N.A. from the central dioptric beam, as affirmed by Eichorn, Abbe, and the anonymous writer of the article on microscopic vision in the R. M. S. Journal,* then the theoretical limit tables at the back of the Journal had better be torn up. The intercostals would count about 95,000 per in., and according to those tables they would cause the spectra of the first order to diverge about * 99 N.A. from the dioptric beam. So it would require an aperture of nearly 2*0 N.A. to grasp all the six. Therefore all these years the tables at the back of the R. M. S. Journal, and the anonymous article on microscopic vision, which is a condensed summary of all their and Prof. Abbe’s teaching on the subject, are, as I have often pointed out, contradictory. This last experiment on the Triceratium with only the spectra of the first order admitted, shows that on focal alteration only a change from positive to negative diffraction images takes place, i. e. black to white dots ; in other words, a black hexagon with a white centre changes to a white hexagon with a black centre and vice versa. The word hexagon is here incorrect ; the pattern strictly speaking under these conditions is black or white circular dots arranged in a quincunx form. This experiment is most important, because it shows that when a small cone of illumination is used a more truthful image is secured by * R.M.S.J., Ser. 2, vol. i. pp. 354. 102 SUMMARY OF CURRENT RESEARCHES RELATING TO reducing the aperture of your objective until all spectra are cut out, except those of the first order. The reasoning is as follows : With a small cone and an aperture sufficient to take in many orders of spectra on focal alteration, you obtain a series of changing images similar to those seen in a kaleidoscope. Without a priori conclusions you do not know your focus, consequently you cannot select the true diffraction ghosts from among the false diffraction ghosts. But the moment the aperture of the lens is contracted so that only the spectra of the first order are admitted, one image and one image only is possible. This image is certainly not a very good image of the structure, nevertheless it cannot be very dissimilar. In the case before us, instead of getting well-defined hexagons like those of a bee’s honeycomb, we have in place of them circular bright spots, spaced correctly and in arrangement precisely similar to the original. But it may be urged that all this only applies to diatom work, and has nothing whatever to do with ordinary microscopical objects. If you will pardon me for a moment I will endeavour to prove to you that it is of the highest importance with regard to almost every microscopical object, But first let me draw your attention, before leaving the Tri- ceratium, to a false diffraction ghost of the second degree (fig. 11). This picture is only possible when four orders of spectra are admitted. Here you will notice that each bar of the hexagon is broken up into three dots, and six spots with a central one are imaged in each areola- tion. This is a difficult one to photograph on account of the great brightness of the areolations, which accounts for the images in those parts being weak. To show that this is a subject not at all confined to diatomic structures, the next experiments will be performed on the eye of a fly. The spectra arising from this structure are identical with those from similar diatomic structures, only they are not so widely spread out, the intervals being 1/800 in. This proves that diffraction does not begin at 1/2500 in. I will first project the critical image (fig. 12) taken with a 3 4 cone X 165. The illuminating cone was now reduced, and the spectra, as in the next picture, allowed to pass into the objective (fig. 13). We now get the Eichorn intercostals. This shows that the diffraction theory has just as important a bearing in connection with a common entomological object as with a diatom. The next picture (fig. 14) was taken with a large cone, but the aperture of the lens was reduced so that it should bear the same proportion to the eye of a fly as an oil-imm. of 1 *4 N.A. does to the P. angulatum. Here you will notice that the hexagon runs into a kind of square shape. A similar appearance can be obtained with a P. angulatum. The structure of the eye of the fly being very coarse it is possible to pick up the whole of the diffracted fan ; this, as seen at the back of the objective, is in itself such a beautiful object that I have endeavoured to produce it, but as yet without success. It is a beautiful star with hyperbolic edges, and is, as far as I am aware, unknown, nor figured anywhere. If this whole diffraction fan be admitted to the objective, then we get a false diffraction ghost of the third degree (fig. 15), and this is the last and most complicated ghost you can have. The founda- ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 103 tion of the picture is composed of three lines drawn at 60° to one another, the third line passing through the apices of the rhombs. I will next project a false diffraction ghost of P. formosum, showing intercostal dots (fig. 16). These were produced in precisely the same manner as the others. The focus, you will notice, is only slightly within the true focus. The greater the aperture of the objective used the less out of focus the object requires to be in order to produce the intercostals. Now I have shown you the three degrees of diffraction ghosts ; these are all produced, and can only be produced by the small cone. It cannot be wondered that Prof. Abbe and his exponents say that “ whether for example, P. angulatum possesses two or three sets of striae, whether striation exists at all, whether the visible delineation is caused by isolated prominences, or depressions, &c., no Microscope, however perfect, no amplification, however magnified, can inform us.”* Again, we read “ that every attempt to discover the structure of finely organized objects - as, for instance, diatom-valves — by the mere observation of their microscopic images, must be characterized as wholly mistaken.” And again, “ The interference images of minute structure, however, stand in no direct relation to the nature of the object, so that the visible indications of structure in a microscopical image are not always or necessarily conformable to the actual nature of the object examined.” The explanation of all this is that Prof. Abbe takes cognizance of one kind of image, and that one a diffraction ghost, and it is perfectly true that so long as you are dealing with diffraction ghosts you cannot, for certain, determine the nature of the structure you are observing. At different foci when a small cone is used there are different images, and without a priori knowledge it is impossible to determine the correct focus, and consequently the true diffraction ghost. Now it is the function of the condenser to put an end to all these difficulties ; it enables you to illuminate by means of a wide-angled cone, and then you have a true image at one definite focus, and at any other focus there is no image at all to confuse you. Of course it must be understood that when the structure is very fine, and the spectra are diffracted through great angles, your widest- angled cone really becomes a narrow one in relation to that structure ; and then you are obliged to make the best you can with diffraction ghosts. But there is, on that account, not the least reason why, for all coarser structures, you should not have a true diffraction image by means of a large cone instead of either a true or false diffraction ghost by a small cone. Eventually our diffraction ghosts with very fine structures and wide-angled cones may through increase in the apertures of our objectives and improvements in our condensers, be changed to true diffraction images. Prof. Abbe’s last paper takes account only of small differences between very similar images, and ignores altogether the enormous differences due to the union of different orders of spectra and the exclusion of others. He is in fact straining at the gnat and swallowing the camel. In his paper he disregards the possibility of getting (to * xiv. (1875) p. 220. 104 SUMMARY OF CURRENT RESEARCHES RELATING TO return to our former simile) a picture of a hayrick instead of a dog, while he insists that a small cone is preferable to a large one lest the • dog appear foggy. To which I reply that a foggy dog is preferable to a hayrick, however sharp. When the illuminating cone is enlarged so that it fills about 3/4 of the back of the objective, one image, and one image only, can be produced, which, as I have said, goes in and out of focus as a daisy under a 4-in. There can be now no doubling of the structure, and no multiple images are produced. Spherical aberration in the lens merely veils the image under an appearance of fog or mist. The clear- ness and distinctness of the image may be marred by its means, but the image cannot be altered in form. 1 have only one more point to bring to your kind notice, and that is the statement that the wide- angled cone, by means of the superposi- sion of dissimilar images, obliterates uncoloured histological tissues.* The truth regarding this is that the wide-angled cone gives you a faithful representation of uncoloured histological tissues (very likely not the preconceived images regarding them), blotting out all those parts which are out of focus. In other words, it gives you a truthful picture of a definite plane in the structure. To illustrate this I have selected the thinnest and most transparent histological object, and one which would be more likely to be blotted out than any other with which I am acquainted. I have photographed this both with a wide and narrow cone, and you shall judge for yourselves which is the more faithful picture. The object is cartilage in a young rat’s tail, of which I will project a low power view, X 8, in order that you may identify it. I now show you an image (fig. 17), X 390 diams., taken with a small cone. The most prominent features in this image are the parts which are out of focus. I wish to draw your particular attention to a cell- wall seen end-on running nearly in a vertical direction in the centre of the slide. The focus was adjusted precisely on that point, and I would like you to notice the apparent thickness of that line. I will now show you the same object (fig. 18) taken by a large cone, and you will at once understand the extreme tenuity of that particular cell- wall which in the previous picture was so thickened by false diffraction ghosts. This picture, I maintain, is a true representation of an exquisitely thin cell-wall ; there is no blotting out of any structure in focus, only a removal of false diffraction ghosts. Of course it may be useful to produce a false image for the purpose of obtaining an idea as to the relative position of the part in focus to those parts out of focus. But this has nothing to do with the bare fact of the obliteration of structure by means of a wide cone. In conclusion, I believe the objection to the use of a narrow-angled cone to be due to the fact that it emphasizes zonal differences, and the efficacy of the wide-angled cone that it as far as possible neutralizes the effect of those differences. Prof. Abbe states (p. 724) “ there is not the least rational ground, nor any experimental proof, for the expectation that this mixture [he is alluding to the mixture of slightly dissimilar images in consequence of the employment of a wide cone] should come nearer to a strictly correct projection of the object than that image which * R.M.S.J., 1889, Part G, p. 723. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 105 is projected by means of a narrow axial illuminating pencil.” Now, I take it that I have proved to you this evening one thing at least, that there is rational ground and experimental proof for the expectation that this mixture does come very much nearer to a strictly correct projection of the object than that image which is projected by means of a narrow-angled illuminating pencil. Finally, I am of opinion that a correct understanding of diffractional effects will, more than anything else, tend to produce in the minds of microscopists a true appreciation of the importance of the achromatic condenser.” Apparatus for the rapid change from parallel to convergent polarized light in connection with the Microscope.* — Dr. E. A. Wtilfing gives a description of an apparatus invented by himself, Fig. 4. intended to' save time in studying mineral or rock sections by polarized light. A plate S (fig. 4), sliding in a groove beneath the stage of the * Neues Jalirb. f. Mineralogie, 1889, ii. p. 199-202. 106 SUMMARY OF CURRENT RESEARCHES RELATING TO Microscope, bears on its under surface two vertical tubes containing two Isicol prisms N c and Np, one of which N c is permanently arranged for observation by convergent light, i. e. with the usual two convergent lenses, whilst the other Np bears the usual lens employed in observa- tions by so-called parallel light. Both of these polarizers, together with their lenses, can be raised or lowered independently of one another by means of suitable forked two-pronged levers H c and H p. \\ hen changing from one form of illumination to the other, the Nicol prism last in use is pushed down, the plate S is slid in its groove so as to bring the other Nicol to the centre of the stage, and this second Nicol is then raised by its lever into position beneath the mineral section. These four stages in the process are shown in the diagrams I. to IV. (fig. 5), where I. shows Nicol N c in its highest position, Fig. 5. beneath the section ; Nicol N p in its lowest position on one side, not in use. II. Nicol N c in its lowest position beneath the section ; Nicol N p in its lowest position on one side, as before. III. Nicol N c in its lowest position, pushed aside ; Nicol N p in its lowest position beneath the section. IV. Nicol N c in its lowest position, pushed aside as before ; Nicol Np in its highest position beneath the section. The catch or stop at A can be turned aside to permit of both polarizers being pushed aside for observation by ordinary light. Dr. Wiilfing has the apparatus attached to a Fuess No. 1 large Microscope. It would require special fitting to other patterns. The apparatus is made by Zimmermann, Mechaniker, Hauptstrasse, Heidelberg, and costs, without Nicol prisms and lenses, 60 marks. It will be observed that two polarizers are required. Bulloch’s improved Filar Micrometer. — Fig. 6 shows this in- strument, of which a short description was given in this Journal for 1886, p. 132, in which we described it as having a second screw, worked by a milled head at the opposite end to the micrometer-screw, which moves both sets of lines together, so that it is possible to set the graduated screw-head at zero for any particular measurement. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 107 Mr. Bulloch now describes it as follows : — “ The improvement con- sists in the secondary slide, by which the whole micrometer is movable ; avoiding the uncertainty of adjustment made by the ordinary micro- meter in getting contact with the cross-hair at zero ; as the amount of Fig. 6. spring with the best mechanical stage (excepting micrometer stages) prevents the cross-hairs being brought gently and perfectly in contact with the object to be measured.” Mr. Bulloch writes as follows with regard to the additional diagonal lines shown in one of the small figs. : — “ From my experience in com- paring micrometers and getting the value of divisions of the screw, much better results can be reached by intersecting the line on the micrometer with the cross line in the eye-piece micrometer; for when using the ordinary filar micrometer it is almost impossible to judge the amount of space left between the line on the micrometer and the spider line.” ,C4) Photomicrography. Photomicrographs and Enlarged Photographs. — At the December meeting of the Society, Mr. J. Mayall, jun., read the following note: — The application of photography to microscopy has received in recent years so great an impulse from the introduction of the dry-plate processes, that the Society has received very large accessions to its collection of photographs — especially of such as have been produced with a view to illustrating various theories of diatom structure. Apart from the question how far it is legitimate to infer the structure of such diatom valves either from the images seen in the Microscope or from those produced by photomicrography — a question which Prof. Abbe’s researches appear to answer in the negative — it appears to me that, unless great discretion is used, the after-processes of enlarging from photomicrographs may easily lead microscopists astray in giving fictitious appearances of contrast in the structure, leading to the belief that such strong images must necessarily represent what was visible in the Microscope. It is well known that photomicrographs frequently give a very erroneous rendering of the different tints seen on delicate 108 SUMMARY OF CURRENT RESEARCHES RELATING TO and transparent objects in the Microscope; and when this erroneous rendering is supplemented by the artificial contrasts due to chemical intensification of the original negatives, or to the after-processes of copying and enlarging, it becomes of the first importance in cases where photographs are brought forward in illustration of special points, that either the original negatives, or reproductions of them as exact as possible, should be exhibited. When, as in many cases — notably by Dr. Van Heurck — enlarged photographs are brought forward without any precise description of the process of their production, and without the original photomicrographs for comparison, useful criticism is difficult if not impossible. All that can be said about them amounts to expressions of vague astonishment that the image should look so strong and so highly magnified. I think it would be advisable in all cases to distinguish between photomicrographs produced with the Microscope, and enlarged photographs from photomicrographs : the former can only be usefully criticized by one who is familiar with the object as seen in the Micro- scope ; the latter need other criteria whence their utility may be estimated, and, above all, they need the presence of the originals from which they were enlarged. (5) Microscopical Optics and Manipulation. The full Utilization of the Capacity of the Microscope, and means for obtaining the same.* — In a paper read before the American Society of Microscopists, Mr. E. Bausch said: — The cover-glass may truly be called a necessary evil, for while absolutely required in micro- scopical investigations, there is no adjunct to the Microscope that has been and is productive of so much evil, and has so retarded the utiliza- tion of benefits made possible by the advance in the construction of objectives. This fact was appreciated as early as 1837, when the angular apertures were what would now be considered extremely limited, and the appreciable effect of variations in thickness of cover-glass was not then nearly so pronounced as it is at the present time, even in modern objectives of a narrow angle. The accommodation for the different thicknesses was obtained by varying the distance between the systems of objectives, and has been followed with modifications in the mode of obtaining the necessary motion up to the present day. While open to some objection, it accomplishes the purpose quite satisfactorily, and must continue to be used until something better is suggested. One of the purposes of the homogeneous immersion is, as we know, the avoidance of the necessity of the cover-correction, in that the cover- glass, immersion fluid and front of objectives are to be one homogeneous mass, but even under these conditions, which in practice were found to be not constant, it has been found advisable to provide cover-correction to obtain the highest possible results. However, even should this not be found necessary in the development of improvements in this class of objectives, it must be remembered that the majority of objectives will always be dry, and especially so when such improvements, which we hope are still to be made, are accomplished. It is an unfortunate circumstance that with this class of objectives the influence of variation * Microscope, x. (1890) pp. 289-96. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 109 in thickness of cover-glasses is most apparent ; but since it is so, wo should, if possible, provide an agency which, eliminating the personal factor of efficiency, will give under all conditions, results closely equal to those under which the objectives were originally corrected. It is surprising to see how little attention is paid to this subject in the large majority of standard works on the Microscope. Almost all books give carefully prepared illustrations and descriptions showing the effect on the course of light by the interposition of the cover-glass, and after giving conclusive evidence of its disturbing influence, still, in a general way, say it is of little moment. Thus, in a German work of the highest standing, which has also been translated into the English language, is found the following utterance, freely translated : — In regard to modern Microscopes, which we have had opportunity to examine, we have not found the differences in thickness such as occur in commercial cover-glass, when, for instance, three to six are equal to a mm., have any noticeable influence on the microscopical image.” In another work of great popularity are found the following quota- tions : — “ That the effect of thickness of cover-glass has a great influence on the perfection of the microscopical image is beyond the slightest question, and certainly deserves the most careful attention of the optician as well as the observer, but whether the devices for its removal are of such great importance and so absolutely necessary as it is claimed, is another question.” “ On the other side, the difference in the cover-glass used in different directions for the most delicate preparations is hardly of any account. I, at least, possess, besides my individual preparations covered with glass of about 1/5 mm. thickness, a collection of objects which I obtained from London and Paris, in which there is such a slight difference of cover-glass thickness that I can observe them all with my objectives of powers from 2 to 1*3 mm. (equivalent to about 1/12 to 1/20 in.) without showing the slightest difference in optical qualities, and in the definition and clearness of the image under the same illumination, as I have convinced myself by careful comparative tests.” With such statements to guide the microscopists, it is not surprising that the subject should have received so little attention, and that any efforts to lead to improved methods of manipulating objectives should have almost completely failed because of a lack of the true understanding of their need and consequent failure to create interest. The belief is quite general that any time devoted to this subject is wasted, and might better be utilized in other directions. 1 hope to be able to show that this is entirely wrong, and may here say that while I may be considered an extremist in the other direction, my efforts emanate from the desire to put it in the power of every microscopist to obtain the highest possible results from his optical battery, and equal to those obtainable by the optician. When, in 1887, Prof. S. H. Gage addressed a circular letter to all opticians in the world inquiring for the dimensions of their standard tube-length, as well as for the thickness of cover-glass which they used as a standard in the correction of objectives, I looked forward to the result with considerable interest, as it would bring together data which it was impossible otherwise to obtain. 110 SUMMARY OF CURRENT RESEARCHES RELATING TO At the meeting of this Society in 1887 at Pittsburgh, he gave the results of his efforts, which show some astonishing facts. I would here say that while for a long time I had felt that a system that would permit the full utilization of the optical capacity of objectives of different makers under varying conditions of cover-glasses was desirable, I was then forcibly impressed with the absolute necessity of a plan which would offer this advantage. One is as much surprised by the differences in cover-glasses used by various makers in correcting non-adjustable objectives, as by the great differences in the length of tube, which in- fluences so considerably the spherical aberration of the objectives. With a thickness of 0*1 mm. for the thinnest, and 0*25 mm. for the thickest, it is only too apparent that with the additional variation in lengths of tubes, it is bevond the power of the microscopist to obtain even approximately the best results from his objectives. More than this, a large quota of the advance made in recent years in the capacity of objectives has been lost. As Prof. Gage states, “ A uniform thickness for cover-glass for unadjustable objectives seems also desirable,” and this would be the easiest solution of the question, but while, on the one hand, the makers of objectives have not yet agreed to use one standard on account of the technical difficulties involved in departing from their established precedent, on the other, the microscopist would hardly be willing to bear the expense which would be occasioned by the loss of cover-glass not conforming to the standard, in order to use those of one thickness. This expense might be greatly reduced by using selected covers of one standard on objects for all medium and high-power objectives, and the balance on all other preparations, on which only low powers would be used, but this would of course be of little avail in face of the fact that manufacturers follow no standard. The greatest difficulty is met with non-adjustable objectives. As is well known, compensation for thickness may be obtaiued in the proper adjustment of tube-length, but while not all Microscopes are suitably provided with draw-tubes, the requisite experience and skill are lacking with a large number of microscopists to make the correction properly in this manner, as well as in objectives especially provided with collar correction. I am sure that microcopists of long experience will bear me out in the statement that results with adjustable objectives depend upon individual skill, and that many such objectives now in use fail to give results corresponding to their capacity. It would seem, therefore, that any system to permit the full utilization of the capacity of objectives should depend on no personal factor, in fact, should be mechanical, and this I have followed out in the system that I shall explain. In an objective corrected for normal thickness of cover-glass there will be spherical over-correction with thick covers and under-correction with thin covers, the amount of correction varying in a different ratio to the amount of variation from the normal thickness. The chromatic correction will also lose correspondingly, but not to so high a degree. While a deviation of a few hundredths of millimeter in either direction will not signify, that which occurs in covers classified in price lists under one number is sufficient seriously to affect, and in the higher powers totally obliterate the definition, which under normal conditions it may possess. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. Ill The microscopist is therefore not obtaining such results as his objectives should enable him to obtain, and the efforts of the conscientious optician to provide classified objectives of reliability and similar performance are almost entirely nullified. In making the necessary experiments some astonishing results appear. With a non-adjustable dry 1/5 corrected for a cover-glass of O' 16 mm., employing the extremes of cover-glass Fig. 7. THOUSANDTH! , lo , Of INCH | 1 \CL |3 |4 Is [6 11 18 19 ho III |I2 |I3 , |I4 1 15 |I6 ( 17 ||8 1 19 HUNDREDTH OFMtti 1 1 1 1 1 1 1 1 1 1 '1° 1 1 1 1 nn I 1 2I° 1 l l l 1 1 1 l l 3|0 | | f 1 1 1 1 I I 40 1 1 1 ill I I 1 5(0 NON adjustable. fJ[ li '4 94 24 H 1% 6% 6 S4 D A 1 1 O ^1 1 O 1 A Alin AnT 1 A a 1 A n OBJECTIVES | CORRECTED FOR rS 13 10 84 8 7 64 5/a 4% — BAUSCrl & LOMB OPTICAL C 9 ■ - Rnrur ctfq MV Mc\a/ Yaru Pitv 046Mm COVER CLASS) 15 II 84 IX 6 4/i nULMt-5 It-N .|N.r. o< INt-W iUr\l\vllT. lUBEUNClM^INtMES^- \Vi \2>i 84 6 4 TUBELENOTH ISO Mnv& 240 Mm 190 160 135 110 > which are used by the various manufacturers as standard as obtained by efforts of Prof. Gage, I found that for 0*25 mm. a tube-length of 6 in. is required to obtain the proper correction, while for a thickness of 0*1 mm. 13 in. of the tube-length are necessary. In a 1/8 objective adjusted under the same conditions, 4J in. are the requisite for a cover of 0*25 mm., and for 0*1 mm. 15 in. The further fact is shown that with a 1/5, which under conditions of tube-length and cover-glass given above shows certain structure well defined, absolutely fails to show anything of it under a cover-glass of 0*1 mm. on one side and 0*25 mm. on the other, and further a marked chromatic over or under correction. With a cover of 0*14, which would seem but a slight variation from the standard, the objective is spherically highly under- corrected, and with 0*18 highly over-corrected. With objectives of high power the difference is still more marked. For these experiments I have had Mr. J. D. Moller, of Germany, mount a series of Pleurosigma angulatum dry and Amphipleura pellucida in balsam under a series of covers varying from 0*1 mm. to 034 mm. each carefully measured and marked. I have used these objects because they are my favourite tests, and it goes without argument in saying that any preparation showing structure under the above objectives will be affected to the same extent by the varying conditions of cover-glass as these objects, and in objects of still finer structure the limit of visibility will be reached corre- spondingly sooner. The system which I have devised to aid in overcoming these diffi- culties depends in the first instance upon a micrometer for measuring the thickness of cover-glass. While the delicate instruments made by M. Grossman, of Germany, are excellently suited for this purpose, they are expensive. I have endeavoured to overcome this objection by construct- ing a plain screw which, while not so sensitive to the touch, is suf- ficiently so for all practical purposes. The instrument is provided with a stand of japanned iron. Out horizontally through the top is a thread of 1/50 in. pitch, and 3/16 in. outside diameter ; a recess is cut on the top below the line of the screw, and at right angles to it for placing the covers. The one-half of the top of the stand which receives the micro- meter screw is slotted longitudinally to the depth of the screw, and is provided with a set screw to take up wear. The other half has the 112 SUMMARY OF CURRENT RESEARCHES RELATING TO fixed screw, adjustable, however, for final adjustment. The end of the micrometer screw is milled, but of a small diameter, so that no force can be exerted to endanger the cover- glass. Fixed on the screw between two nuts is a brass drum with a 1/2 in. face ; a knife-edge index-finger is fixed to the top of the stand, and projects over the top of the drum ; to the outside diameter of the drum is fixed a strip of glazed paper Fig. 8. Actual size. provided with a series of divisions. The first gives the thickness of cover-glass in thousandths of in., the second in hundredths of mm. The third indicates the proper tube-length with various thicknesses of cover-glass with a non-adjustable 1/4 corrected under a tube-length of 8^ in., and cover thickness of O' 16 mm. ; the fourth gives the tube- length of a 1/5 in. objective under the same conditions; the fifth for a 1/8, and the sixth for a 1/12 for same conditions of tube-length and cover ; the seventh is for a 1/6 with the same cover, and tube-length of 160 mm. In objectives provided with cover correction the graduation is so arranged as to read to 0* 01 mm. No matter what the power of objective or whether dry or water-immersion, the number gives proper correction for a thickness corresponding to it. Thus, with a cover-glass of ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 113 •20 mm. the collar of such an objective needs merely to be set at 20 to give the proper correction, and consequently the best results. On the other hand, with an objective which is graduated on this system, the correct thickness of cover-glasses can be determined by obtaining the proper correction on preparations previously made, but on which the thick- ness of cover-glass is not noted, and the thickness may be marked on them for future convenience. To do this successfully, however, con- siderable experience is requisite. All the other scales give the correct tube-length in inches and millimetres for covers corresponding to them, and in this manner offer a ready and definite means of correction. The tube-lengths required for the thinnest and thickest covers are so extreme that probably no convenient means for obtaining them can be practically arranged, but they can be so approximately if not entirely. At any rate, the micrometer will detect the requirements before using the covers, and those deviating considerably from the normal can be used on objects for use with low powers only, in which case the effect will not be very appreciable. In this system I do not overlook the fact that variation in tube- length involves a variation in magnifying power, but except in cases when micrometers are used, I consider this of secondary importance, as it always is in comparison with the results obtained in resolving and defining power. This system involves four conditions : — First. That all cover-glass be measured before using, and that the thickness be noted on the preparation. Second. That for convenience all draw-tubes be marked in inches or millimetres, or both. Third. That adjustable objectives be corrected according to this scale. Fourth. That the same tube-length and cover-glass thickness be used in all original corrections of objectives. As regards the first condition, there are many microscopists now who measure all their covers before using them, but the mere knowledge of thickness has been of no value up to the present time, because this in itself has been no guide in obtaining better results except by approxi- mation. My aim in connection with this system has been to devise an instrument which shall possess a high degree of accuracy, and shall still be so inexpensive that its price should be no obstacle to its general use. The celebrated preparer of objects, Mr. J. D. Moller, and others, have kindly agreed to mark the thickness of covers on their objects, so as to aid in the introduction of this system, and other preparers can no doubt be induced to do so if its advantages can be proved. As regards the second point, many manufacturers now graduate their tubes, and modern requirements demand that this should be more generally done. Our company intends, as soon as it can possibly arrange to do so, to graduate the tubes of all its instruments. As to the third and fourth conditions, I cannot, of course, presume to ask manufacturers to adapt their standards to this system. While it will be a convenience to a large number of microscopists, I must leave it to the merits that this system may possess, to exert their influence in this direction. 1891. I SUMMARY OF CURRENT RESEARCHES RELATING TO 114 On the Amplifying Power of Objectives and Oculars in the Com- pound Microscope.*— Dr. G. E. Blackham writes : — “ A great deal has been said and written on this subject, and still the matter is not as clear and accurate as could be desired. The European opticians usually name their objectives and oculars in an arbitrary manner, as No. I., No. II., No. III., &c., or A, B, C, &c., but these designations give no clue to the amplifying powers, except that the lower numbers or earlier letters usually indicate the lower magnifying powers. The No. I. objective of one maker does not, how- ever, necessarily correspond with the No. I. of another maker, and the No. I. objective does not necessarily correspond in amplifying power with the No. I. ocular of the same maker. The English makers have attempted to avoid this confusion and, to introduce a degree of uniformity, have long adopted a system of nomen- clature based upon the amplifying power; that is, if a combination of lenses magnifies equal to a single convex lens of one-inch focus, the combination is called a one-inch ; if the same as a single lens of one- quarter inch focus, it is called a quarter-inch, &c., &c. This system has long been in use in England and this country for objectives, and more recently has been extended to oculars (or eye-pieces, as they are com- monly called). This was supposed to give a very simple and accurate means for determining the power of any objective or ocular or com- bination of objective and ocular, provided only that they were correctly named by the maker and were used on a tube of the standard length. The rule commonly in use is based upon the assumption of the arbitrary distance of ten inches as the distance of distinct vision, and that the number of times the focal length is contained in ten inches is the ampli- fying power ; so that a one-inch lens would magnify ten times, a one- fourth inch forty times, a one-tenth inch one hundred times, &c., &c. The image of the object projected by the objective being again magnified by the ocular, it was further assumed that the same rule would apply, and therefore that the amplification produced by the combination of a 1/10 objective with a one-inch ocular would be foimd by multiplying the assumed power of the 1/10 objective (100) by the assumed power of the one-inch ocular (10) = 1000 diameters. And so, by the appli- cation of this simple rule, every owner or user of objectives and oculars of the new nomenclature could calculate correctly the theoretical power of each and of any combination, with the understanding that, if the distance between the optical centre of the objective and that of the ocular varied, the amplifying power would vary in proportion. The object of the present paper is, 1st, to show the incorrectness of this rule, in that the real image projected by a simple convex ten inches from its optical centre is not amplified the number of times the focal length is contained in ten inches, and that the same rule of amplification that is true and correct for the objective that projects a real image cannot be true and correct for the ocular, which projects a virtual image ; and, 2nd, to present a correct method of determining the (linear) amplifying power of any objective or ocular, correctly named on the equivalent focal length system, and of any combination of such objective and ocular at any given distance between their optical centres. * Proc. Amer. Soc. Microscopists, xi. (1889) pp. 22-31. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 115 Now, in so far as tlie amplification of the image projected by the objective is concerned, the distance of distinct vision is of no consequence whatever, but the result is governed solely by the well-known optical law that, “ The linear dimensions of object and image are directly as their distances from the optical centre of the lens.” The correctness of this can be demonstrated by actual measurement, for the image is as real as the object, and its distance from the optical centre of the lens and its dimensions can as easily be measured. Before proceeding to the further discussion of this subject it may be well to define some of the optical terms which I shall be obliged to use. I am quite aware that, for the majority of my hearers, this is a work of supererogation that almost savours of impertinence ; but there are always beginners amongst us, and it is for their sakes that I insert these elementary definitions. Definitions. — Optical Centre. — The point through which all rays traversing a lens with parallel directions at incidence and emergence must pass. In double convex or double concave lenses it lies in the interior of the lens; in plano-convex or plano-concave lenses it lies on the curved surface ; while in a meniscus of either kind it lies outside the lens altogether. Principal Axis. — The straight line passing through the centres of curvature of both faces of a double convex, a double concave, or a meniscus lens, or passing through the centre of curvature of the curved face and cutting at right angles the plane face of a plano-convex or a plano-concave lens, is called the Principal Axis ; the optical centre is always in this line. Secondary Axes. — All other straight lines passing through the optical centre are called “ Secondary Axes.” Principal Focus. — The point at which rays originally parallel to the principal axis are made to converge (approximately) to one point. Focal Length. — The distance from the optical centre to the principal focus. Conjugate Foci. — Rays emerging from a point more distant than the principal focus on one side of a convex lens and passing through the lens will be brought to a focus at a point on the other side of the lens, and the points thus related are called conjugate foci. As one conjugate focus advances from infinite distance (parallel rays) to the principal focus, the other recedes from the principal focus to infinite distance, the most distant focus always moving most rapidly, and the least distance between them is therefore attained when they are equidistant from the optical centrf , in which case the distance of each from the optical centre is CZ /, and their distance from each other 4 /. If either is less than the principal focus, then the other becomes negative ; that is, the rays are no longer brought to a focus on the opposite side of the lens, but are only rendered less divergent, as if coming from a more distant point on the same side, and this point from which they appear to come (the more distant of the two) is called the virtual conjugate focus. In this case, as one conjugate focus advances towards the optical centre, the other advances in the same direction till they become coincident. Secondary principal and conjugate foci exist in each of the secondary i 2 116 SUMMARY OF CURRENT RESEARCHES RELATING TO axes of a convex lens, and are under the same laws as the primary foci. Each point in an object has its conjugate point in the image of it formed by a lens, and this image, if on the opposite side of the lens, is real and inverted ; if on the same side, is virtual and erect. The linear dimensions of the object and image are directly as their distances from the optical centre of the lens ; so that, if the object be nearer than the image, then the image is magnified, and vice versa. Formulae. — The formulas for the determination of the conjugate foci when / = principal focus (or focal length) ; p = one conjugate focus ; p' = the other conjugate focus. When the conjugate foci are on opposite sides of the lens (real image) : 1 i _ 1 p + p' ~ f ' This formula suffices for the determination of either of the conjugate foci, the other conjugate focus and the focal length being given ; or of the focal length, the two conjugate foci being given ; and as it applies equally well to points in the secondary axes, it suffices equally to deter- mine the distances of the object and image (and thence their relative linear dimensions), if one of these distances and the focal length of the lens be given. When the conjugate foci are on the same side of the lens (virtual image) the formula becomes 1 l l p~p'~ 7 ' The plus sign here becomes minus, or, to express it in other terms, as the two conjugate foci are now on the same side of the lens, it is the difference instead of the sum of their reciprocals that equals the reciprocal of the focal length. This formula is as applicable as that for real con- jugate foci to the determination of the places, and therefore of the relative linear dimensions, of image and object ; but, of course, the change of sign produces marked differences in the results when the given quantities are the same ; that is to say, with a given focal length and image distance, the distance of the object, and therefore the ratio between its linear dimensions and those of the image, will vary according as the image is real or virtual. In the compound Microscope we have to deal with both real and virtual images ; the real produced by the objective, and the virtual by the ocular. The real and inverted image produced by the objective becomes in its turn the object of which the ocular produces a virtual image ; erect so far as it is concerned, but, of course, still inverted as regards the original object. The degree of amplification of the real image produced by the objec- tive depends upon two factors : 1st, the focal length of the objective, and, 2nd, the distance from its optical centre at which the image is ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 117 formed. It can be formed at any distance from the focal length of the objective np to infinity. In most Microscopes of the English and American model the tube is of such length that the image is formed at a distance of about ten inches, and that distance is therefore taken as the basis of calculation, and the formula then is 1_ 1 1 1 _ 1 1 j p (object distance) p' (image distance) / (focal length) * or, substituting tho image distance 10 for p' : 1 7 With this formula let us work out the case of a 5-in. objective ; then 1 _1 p + TO ~ 5 i a _i_ _ p ~ 5 “ lo “ 10 5 p _ 10 1 " 1 ; p = 1°; that is, the object and image are equidistant from the optical centre, and therefore of equal size, and there is no amplification. Of course, it can be assumed that the image distance p is greater than 10 in., as in case the draw-tube is used, when the formula will show that, with a 5-in. objective, the image is larger than the object, or p' can be taken as less than 10 in., when the formula will show that, with a 5-in. objective, the image is less than the object. Keeping 10 in. for our image distance, let us take the case of a 1/5 in. objective, then / = - • o 1 1 P + To l l l i To 50 10 10 V ~ 49 a (amplification) = 10 1 o 4^ _ 49 10 “ 10 = 49 times. By this formula we can easily calculate the amplification of the real image projected at 10 in. by any simple-convex lens, if the focal length 118 SUMMARY OF CURRENT RESEARCHES RELATING TO of the lens be known ; and I present herewith a table so calculated for most of the focal lengths used for Microscope objectives. (Table A.) It will be noted that the amplifications obtained are, in every case, less than those obtained by the number of times the focal length is contained in 10 in., and the reason is that one conjugate focus (the image distance) being at less than infinite distance, the other conjugate focus (the object distance) must be at a greater distance than the focal length, and there- fore a quantity greater than the focal length must be used for the divisor, and the quotient (the amplification) must be less. As a 1-in. simple-convex lens amplifies the image projected by it at 10 in. from its optical centre 9 times, a 1-in. objective should do the same (without reference to its actual focal length). If it fails to do so, if the image projected by it at 10 in. from its optical centre is amplified more or less than 9 times, then the objective has been incorrectly named ; it is not a 1-in. objective, but something else. The Ocular. — Having disposed of the real image projected by the objective, we come to the virtual image projected by the ocular ; here the formula is i _ 1 _ Jl. V v' - f ’ substituting the image distance 10 for^' we have 1 _1_ _ 1 f 10 - /' With this formula let us work out the case of a 5-in. ocular : 1 1 _ 1 p “ 10 ” 5 11 JL_ 3^ p ~ 5 + To “ lo 10 * = T 10 30 The wide difference of this result from that obtained for a lens of the same focal length used as an objective shows very plainly the absurdity of using, as many of us have done, and as many of the books teach, the same general rule for determining the amplifying power of objective and ocular, viz. to divide 10 in. by the focal length expressed in inches. I present herewith a table of amplifications of virtual images pro- jected at 10 in. by simple lenses corresponding to the most commonly used oculars. (Table B.) The total amplifying power of any combination of objective and ocular is obtained by multiplying the amplifying power of one by that of the other. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 119 For instance, tlie total amplifying power of a Microscope with tube of standard length carrying a 1-in. objective and a 2-in. ocular should be 9 x 6 = 54, instead of 10 X 5 = 50, as per the usual rule. It is to be noted, however, that while the formulae here given are theoretically correct for the objective and ocular respectively, and are applicable to any image distances by substituting the desired imago distance for p', as 10 was substituted for it in the examples given, yet there are many complications in the practical application of any formula to the determination of the actual amplification obtained by the modern compound Microscope ; among these complications are, 1st. The highly complex construction of many objectives, making it very difficult to ascertain with any degree of accuracy the position of the optical centre, which difficulty is still further increased when the objective under consideration is furnished with a correction arrangement for various thicknesses of cover-glass, which, by varying the relative positions of its component lenses, varies its actual and nominal focal length and the position of its optical centre. The exact position of the optical centre of the ocular is also, at times, difficult of determination. 2nd. The refractive condition of the observer’s eye is also a factor in the amplification under which the image is finally seen, for the reason that the dioptric system of the observing eye becomes, in fact, a part of the ocular, and any difference of its refractive power greater or less than that required to focus on the retina rays proceeding from a radiant situated at the given image distance, must be added to or subtracted from the refractive power of the ocular, and thus decrease or increase its focal length. That is to say, a person who can and does accommodate for precisely 10 in. while looking through the Microscope will, if all the other conditions are rigidly complied with, see the image under the exact amplification indicated by the formula, while one, who by reason of myopia or of excessive use of the muscle of accommodation accommodates for a less distance, will see it under a greater amplification, and the emmetrope or hyperope who relaxes his accommodation to less than that required to bring rays from a radiant at 10 in. to a focus on his retina, will see it under a less amplification than that indicated by the formula. For instance, let us take the case of the combination of 1-in. objective and 2-in. ocular for which we have found the total amplication, when image distances are taken as 10 in. in case of both objective and ocular, to be 9 X 6 = 54. If the observing eye be accommodated for just 10 in., the image will be seen clearly and under an amplification of X 54. If, however, the eye is accommodated for any other distance, then the image will not be clearly seen and a change must be made in the adjustment of the Microscope to make it clear. The reason is that the excess or defect of the refraction of the eye above or below what is required to accommodate it to 10 in. has, in effect, been added to or taken from the refractive power of the ocular. Suppose an observer, as the result of myopia or from spasm of, or voluntary action of the muscle of accommodation, accommodates for a distance of 5 in. instead of 10 in. ; he has, in effect, added to the refractive power of the ocular the refractive power of the lens which represents the difference between a refractive power of 10 in. and of 120 SUMMARY OF CURRENT RESEARCHES RELATING TO 5 in. The refractive power of a lens is the reciprocal of its focal length. Hence the equation is 1 1 _ 1 5 “ io “ To* Then refractive power of ocular + excess of ref. of eye == ref. power of eye and ocular taken as one, or 11 G 1 2 + To = To = “1-66 Hence the resulting amplification will be as if the ocular had a focal length of 1*66 instead of 2, and the formula will be 1 1 1 p 10 “ 1-66 1 1 1 11-66 p ~ 1-66 lO “ 16-6 16-6 p ~ TT-66 10 _ 1166 _ 7 a ~ 16-6 ” 16-6 11-66 Hence for the observer whose eye is accommodated for 5 in., the expression for total amplification of the 1-in. objective and the 2-in. ocular will be 9 x 7 = 63. On the other hand, let us take a case much more unlikely to occur in practice, that of a person who by reason of excessive liypermetropia or paralysis of accommodation, is unable to focus any but parallel rays upon his retina, or, in other words, to accommodate for any point nearer than infinite distance. If such an observer make use of the same com- bination of objective, he has in effect subtracted from the refractive power of the ocular the refractive power of the lens, which represents the difference between a refractive power 0 and of 10 in. = 1/10 ; then 1 _1_ _ _4_ _ i 2 "" 10 “ 10 2TT* Hence the resulting amplification will be as if the ocular had a focal length of 2 * 5 instead of 2, and the formula will be 1 _ J_ V ~ 10 2-5 1 10 1 125 1 p ~ 25 + 10 ~ 250 ~ 2 P = 2 ZOOLOGY AND BOTANY. MICROSCOPY, ETC. 121 Hence, for the emmetropic observer whose accommodation is entirely relaxed, or for any observer whose eye is accommodated for parallel rays, the total amplification of the 1-in. objective and the 2-in. ocular will be 9 x 5 = 45. For strict accuracy, the change in the position of the image produced by the objective, if the adjustment for the different eyes be produced in the usual way by means of the fine or coarse adjustment moving the objective to or from the object, should be taken into consideration, but the amount is so small, about 2^ per cent, in the first case, and 5 per cent, in the second, that it may be neglected without seriously impairing the practical accuracy of the general result, while if the adjustment for different eyes be made with the draw-tube moving the ocular only, the position of the image produced by the objective is not changed, and therefore, so far as it is concerned, the original formula remains strictly correct.” “ Table A. “ Amplification (linear) of Real Images projected at 10 in. from optical centre by simple bi-convex lenses. Focal Length of Linear Amplifi- ! Focal Length of Linear Amplifi- Lens in inches. cation of Image. Lens in inches. cation of Image. 5 1 1/4 39 4 1-5 1/5 49 3 2-33 1/6 59 2 4 1/7 69 1 9 1/8 79 3/4 12*33 1/9 89 2/3 14 1/10 99 1/2 19 1/12 119 4/10 24 1/16 159 1/3 29 1/25 249 Table B. “ Amplification (linear) of Virtual Images projected at 10 in. from optical centre by simple bi-convex lenses. Focal Length of Lens in inches. 5 4 3 2 Linear Amplifi- cation of Image. 3 3- 5 4- 33 6 7-73 11 Focal Length of Lens in inches. 3/4 1/2 4/10 Linear Amplifi- cation of Image. 14 21 26 31 41 “ Note. — In the Huyghenian ocular (the form most commonly in use) the field- lens, while mechanically part of the ocular, is optically part of the objective, in that it contributes to the formation, not of the virtual image projected by the ocular, but of the real image projected by the objective, upon which it acts negatively, diminish- ing its size while increasing the superficial area brought into view at one time. So that, in this form of ocular it is the eye-lens alone that contributes to the reamplifi- cation of the image, but the negative action of the field-lens must, of course, always be taken into consideration when attempting to determine the amplifying power of a Huyghenian ocular by calculation.” 122 SUMMARY OF CURRENT RESEARCHES RELATING TO New Method for Constructing and Calculating the Place, Position, and Size of Images formed by Lenses or Compound Optical Systems.’ — The late Prof. G. Govi wrote : — “ The theory of lenses and of compound systems has taken a new form, and reached far greater perfection since Moebius, Gauss, Listing, and others have introduced the consideration of certain planes and cardinal points, which simplify the construction of the place, position, and size of the images, allowing account to be taken of the thickness of the refractive medium traversed by the light. But the preparatory operations, either as constructions or calculations, by which we succeed in determining the place of the points and cardinal planes in lenses or systems, are long and wearisome, and often out of proportion to the importance of the result we hope to obtain ; and, above all, it is always most difficult to determine by experiment the place of these planes and points in lenses already worked or in optical systems already constructed. Physicists, therefore, in spite of the practical methods and instru- ments proposed for the purpose by Cornu, Gariel, and others, are for the most part limited to considering the lens as having no thickness, and to calculate directly and for every limiting surface the path taken by the rays in traversing the given media, thus sacrificing a part (and at times not a small one) of the necessary precision, or increasing the fatigue of the calculations when many determinations of the same optical system are in question. The suggestion, therefore, of a quicker method for constructing and calculating the images given by thick lenses will not be unwelcome to students, the same method being also applicable to any optical system whatever. This method requires the determination of two points which, very probably, have not until now been taken into consideration by physicists or mathematicians who have treated of these matters ; probably they passed them unawares, because if any one had pointed out their impor- tance and usefulness they would at once have been recognized, and the very latest treatises on optics would have recalled them. The two' new points, by which the theory of lenses is very much simplified, and which are easily determined by observation, are the images of the centres of curvature of the two faces, anterior and posterior, of the lens, seen through that one of the two faces to which they do not belong. In order to obtain them it is necessary to suppose that the luminous rays diverging from the centre of curvature of one face, or converging towards it, meet the second face of the lens where by refraction they are made to converge towards the image of this same centre, or diverge from that image when it becomes virtual. We thus have on the axis of the lens the places of the two images q and qlt (fig. 9), of the centres c and c1} and of the curvature of the two faces al and 6Zj. Having fixed the position of these two points, which we may call the centric points of the given lenticular system, nothing else is needed to determine any conjugate focus of a point situated upon the axis or out- side the principal axis of the system, and to obtain the size and position Rend. R. Accad. Lincei, iv. (1888) pp. 655-60 (3 figs.). ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 123 of the real or virtual images which may be produced by the system itself. The determination a, priori of these points (like the determination of the points and planes of Gauss and Listing), demands the knowledge of the length and sign of the radii of curvature of the two surfaces of the lens, that of the thickness of the lens, or the axial distance of the two refracting surfaces, and finally that of the relative velocity of light in the three successive media— that is to say, of their relative indices of refraction. We can with these data alone construct or calculate the Fig. 9. o place of the centric points q and qu without first determining the principal foci and the principal distances or anterior foci of the two surfaces of the lens ; we can also, if we wish, determine these quantities which, introduced in successive calculations or in ulterior constructions, abbreviate or simplify the work. In any case, having obtained the two centric points, we have no further need either of the optic centre, or of its two images, or the nodal points of Listing, or Gauss’ principal planes, or the principal foci of the whole lens, to construct or calculate the places, positions, and size of the images. And as such constructions are made very quickly, we may use them in order to find the final effect of any series whatever of surfaces and of different refracting media, centered on the same axis. It is not, therefore, necessary in the case of optic systems to have recourse to the laborious process of construction or calculation by means of successive images, for there can always be determined in every optic system (however complex) the images of the centres of curvature of its first and of its last surface, seen successively through the whole of the rest of the system, observing the image of the centre of the first surface through the second, then the image of this image through the third, and so on to the image of all the preceding images, seen through the last surface, and repeating the same operation in the opposite direction for the centre of the last surface and for its successive images up to the last, which is seen through the first surface. In this way the centric points of the whole system are obtained, by means of which we 124 SUMMARY OF CURRENT RESEARCHES RELATING TO can construct afterwards or can calculate with great rapidity the image of any point placed at any distance whatever from the system. The greater simplicity of the new method arises from considering those rays which undergo neither deviation nor displacement either at the entrance into or exit from the different media, so that the faces of the lens or the external surfaces of the system perform the function of the principal planes of Gauss, the centres of curvature of these surfaces that of the nodal points of Listing, and their images or centric points that of the principal foci of the optic system. Without now entering into minute details of the new method, it wall be sufficient to show how, by having recourse to it, we can easily find the centric points of a given lens, and how, once these points are found, we can easily construct the image of any object seen through the lens. We shall thus see whether the proposed method deserves or not to be preferred to others. In order to find practically the position of the centric points of a given lens, we measure its thickness y, and with the spherometer, or by reflection or otherwise, the radii of curvature r and rx of its first and second surfaces. Having obtained these quantities we place normally to the axis of the lens an object of a known size o g, at a determinate distance a g from one of the faces, and we find the image gl either real or virtual of the object, seen through the lens, measuring this image, and determining its distance b g from the other surface. Then by drawing a straight line from the extremity o of the object to the centre c of curvature of the first face of the lens, this straight line -will cut the last face in a certain point ; by drawing a straight line from the extremity o2 of the image to the centre of curvature cx of the last face, we mark by m the point in which this straight line cuts the first face of the lens. Join ox to wq, the point q, in which the straight line Ox mx cuts the axis of the lens, will be the first centric point, that is, the place of the image of the centre c of the first face seen through the second. Let o be similarly joined to m, the point gu in which the line o m cuts the axis, will be the second centric point, that is, the image of the centre cx of the second face seen through the first. Having thus obtained the points q and ql9 the construction of the principal or conju- gate foci of the system and that of all the images which it can give, can be made exceedingly rapidly, and we can then deduce very easily the places of the principal planes, the nodal points, the optic centre, &c., if we wish to treat the problems relating to the given lens by the methods of Gauss, Listing, or other mathematicians. The preceding diagram shows at once how we may obtain the image of a point o placed outside the axis of the lens. (If the point given were on the axis, we might raise from it a perpendicular to the axis, and determine the image of any point on this perpendicular, drawing from the image obtained a normal to the axis itself. The meeting point of this normal and the axis would be the place of the image of the given point.) Let a straight line be drawn from the point o to the centre c of the face through which it is intended the light should pass ; such a straight line will represent a luminous ray, which starting from o will pass, neither deviating nor displaced through the lens, until it meets in m, the second face. The ray having reached m, will deviate towards the ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 125 point q , the image of c ; draw the line mx q on which prolonged will be found the image of o. From the point o draw through qx the line o q , until it meets the first face of the lens in m. Through m and cx draw the line cx m, which prolonged will pass without deviation out of the lens, and will meet mx q in a point ox ; the point ox will be the image of o. If from the point o the perpendicular o g be let fall on the axis, and from ox the line ox gx , the point gx will be the place of the image of the point g seen through the lens. Iu order to obtain the principal foci of a given lens, draw a radius l c (fig. 10) to the centre of its first face, and draw its corresponding refracted ray mx q, then through the point qx draw qx m parallel to l c, drawing m cx and prolonging it till it meets mx q2 prolonged in S. Fig. 10. The point S will be the image of a point situated at an infinite distance in the direction of c m l. Drawing from S a normal to the axis we obtain in px a principal focus of the lens. The same construction repeated for the other face will give the second principal focus p, or the point of the principal distance of the lens. We can obtain the second focus more quickly when once the first is known, profiting by a very simple relation which exists between the two distances q px and qx p of the two principal foci from the centric points. Representing by r the radius of curvature a cx of the first face of the lens lx, by r the radius b cx of the other face, by x the distance b q of the centric point q from the second face of the lens, by xx the distance a qx of qx from the first face, and denoting by F the distance q px and by Fx the line qx p we readily obtain the following relation : — F — rx + x Fj - r + xx which gives directly F, if we know F1? or F! when F is known. SUMMARY OP CURRENT RESEARCHES RELATING TO 126 The construction of this formula is very simple. From the points q and qx let two normals be drawn to the axis ; through the centre c draw c tx until it meets in tx the normal passing through q1 ; let cx t be drawn through the centre cx parallel to it, until it meets in t , the other normal q t. Having then joined the principal focus p (which we suppose to be known) with t, let a parallel to p t be drawn through tx ; the point px, where it cuts the axis, will be the other focus, or the principal distance of the lens. The same graphic process, and therefore the formulas derived from it, are very easily applied also to optic systems composed of lenses without thickness. In this case we first determine the successive images of the centre of the first and of the last lens seen through all the others ; then, considering the centres of the lenses as we just before considered the centres of curvature (since we suppose the rays to pass through these centres without deviation and without displacement) we make relatively to them and to their images the constructions already indi- cated, and so we solve with rapidity all problems relating to optic instruments composed of thin lenses.” (6) Miscellaneous. “New Inventions.” — “Her Majesty’s Royal Letters Patent have been granted to the inventor of a wonderful as well as useful little appliance. This is a Pocket Microscope and Floriscope combined, about 3 in. in length and 1J in. square. It is constructed upon an entirely new principle, and has a magnifying power and definement superior to some of the most elaborate and expensive instruments, and yet so simple that any schoolboy or girl can use it. Its magnifying power is registered as 150 diameters, or 22,500 surfaces, and distinctly shows all the thou- sands of different kinds of animalcula in water, &c., or any other micro- scopic objects. This new patent was sealed by the Comptroller-General of Patents on the 13th of August last, and is now offered to the public at the nominal price of Is. each, and sent free by parcel post upon receipt of postal order value Is. — stamps not taken — with a 12-page pamphlet of instructions for use, and a large double sheet of engravings in black and gold (with key) free. The inventors and manufacturers also guarantee that, in any case where the instrument is not approved of and returned within reasonable time, a postal order value Is. will be forwarded by return of post. The medical profession, chemists, school- masters, teachers and students, as well as parents and guardians, should send for one on approval. This is no foreign rubbish, but of good English workmanship throughout. Address, Conway Rae & Company, The Premier Patent Microscope Depot, Stafford Street, Birmingham.” Upon reading the above advertisement in ‘ Nature’ * we applied for one of the Microscopes, and were informed that for an additional remit- tance of 6 d. we should receive an instrument of superior make, giving “ better definement,” with four extra “ object-glasses,” and a larger pamphlet of instructions. As we were desirous of comparing the two qualities of Microscopes, we requested both to be forwarded. The lower priced one consists of a tin tube of square section, having a tin diaphragm with square aperture in the middle. At one end is * October 11th, 1890. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 127 another similar diaphragm of stamped brass fitting after the manner of a cap, but with internal flange ; a similar cap, but with deeper flange, is applied at the other end, and this has a circular hole in the centre, against which a blown-glass spherical lens of about 1/4 in. diameter is pressed on the inner side by a tin plate with corresponding central hole. The object is placed between two square plates of glass and thrust up against the lens, a tin diaphragm follows, and these are held in position by a roughly bent piece of tin serving as a spring. The ends of the caps are stamped with an inscription and lacquered ; the tin tube is also lacquered. The higher priced Microscope differs from the other, (1) in having the tin tube coloured in addition to being lacquered; (2) it has four extra pairs of glass plates termed “ object-glasses/’ ; and (3) a fuller pamphlet accompanies it. Whilst wholly disclaiming any desire to depreciate the quality of these Microscopes, we are compelled to state that the whole manufacture suggests that of common toys of tin. And as it would be obviously unfair to compare their optical quality with that of more expensive instruments, we have compared it with a Stanhope lens, such as is com- monly sold in the London streets at the price of Id. each, including wire and tin mounting and a pair of glass plates for clipping objects, and our impression is that the latter is not inferior. The late Mr. Brady, Hon. F.R.M.S.* — We give, almost verbatim, a copy of the best of the notices we have seen of our deceased Fellow. As it is from the pen of Prof. M. Foster, Sec. B.S., it is written by one who knew him well. Henry Bowman Brady was born on February 23rd, 1835, at Gates- head. His father, an esteemed medical practitioner of that place, belonged to the Society of Friends, and retained to the end the dress and manner of conversation of that body. The father’s house, for many years the home of the son, was one of those charming Quaker abodes where strength and quietude sit side by side, and where homely plenty and orderly preciseness hide, for a moment, from the stranger the intel- lectual activity which is filling the place. Though the son, when I knew him, had abandoned the characteristic dress and speech of the society, without, however, withdrawing from the body, the influences of his surroundings moulded his character, making him singularly straight- forward and free from any manner of guile. After an ordinary school career spent in Yorkshire and Lancashire, and an apprenticeship under the late Mr. T. Harvey, of Leeds, and some further study at Newcastle in the laboratory of Dr. T. Bichardson, which may be considered as the forerunner of the present Newcastle College of Science, he started in business in that city as a pharmaceutical chemist in 1855, while yet a minor. That business he conducted with such ability that in 1876 he felt able to resign it to Mr. N. H. Martin, and to devote the whole of his time to scientific work. He contributed to science in two ways — one direct, the other indirect. Of the many scientific movements of the last thirty years or so, one, not of the least remarkable, has been the scientific development of the pharmaceutical * Nature, xliii. (1891) p. 299. 128 SUMMARY OF CURRENT RESEARCHES RELATING TO chemist. Into that movement Brady threw himself with great vigour, especially in his earlier years. He was for many years on the Council of the Pharmaceutical Society, and the progress of that body was greatly helped by his wide knowledge of science and of scientific men and things, as well as by his calm and unprejudiced judgment. His more direct contributions to science were in form of researches in natural history, more especially on the Foraminifera. His first publi- cation seems to have been a contribution, in 1863, to the British Associa- tion as a report on the dredging of the Northumberland coast and Dogger Bank ; his last was a paper which appeared in the October number of our Journal. Between these two he published a large number of re- searches, including a monograph on Carboniferous and Permian Forami- nifera, an exhaustive report on the Foraminifera of the ‘ Challenger ’ ex- pedition, as well as monographs on ParJceria, Loftusia , and Polymorpliina , in which he was joint author. By these works he not only established a position, both in this country and abroad, as one of the highest authorities on the subject, but, what is of more importance, largely advanced our knowledge. Every one of his papers is characterized by the most conscientious accuracy and justice ; and though his attention was largely directed to classification, and to the morphological points therein involved, his mind, as several of his papers indicate, was also occupied with the wider problems of mor- phological and biological interest which the study of these lowly forms suggests. I have myself often profited by his wide knowledge and power of accurate observation in discussing with him questions of this kind arising out of his studies, and learning from him views and opinions which, to his critical mind, were not as yet ripe enough for publication. The leisure of the last fifteen years gave him opportunity for travel, and he visited various parts of the world, utilizing many of his journeys — notably one to the Pacific Ocean — in the collection and study of Fora- minifera. Some of these travels were undertaken on the score of health, to avoid the evils of an English winter, for he was during many years subject to chronic pulmonary mischief. During his last journey for this purpose — one to the Nile in the winter of 1889-90 — he met with difficulties, and failed to receive the benefit from the change which he had secured on former occasions. During the last two or three years, and especially during the last year, his condi- tion gave increasing anxiety to his friends ; the malady against which he had so long struggled seemed to be beating him at last ; and we heard with sorrow rather than with surprise that the fierceness of the recent cold had conquered him. Settled for the winter at Bournemouth, and full of cheerful hopes for the coming summer, he succumbed to a sudden attack of inflammation of the lungs, and died on January 10th, 1891. Science has lost a steady and fruitful worker, and many men of science have lost a friend and a helpmate whose place they feel no one else can fill. His wide knowledge of many branches of scientific inquiry, and his large acquaintance with scientific men, made the hours spent with him always profitable ; his sympathy with art and literature, and that special knowledge of men and things which belongs only to the travelled man, made him welcome where science was unknown ; while the brave patience with which he bore the many troubles of enfeebled health, his ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 129 unselfish thoughtfulness for interests other than his own, and a sense of humour which, when needed, led him to desert his usual staid demeanour for the merriment of the moment, endeared him to all his friends. Angling and Microscopy. — A “ microscopical evening ” could, wo should have thought, hardly be looked for at an angling society, but the following appears in ‘ Flood and Field ’ of the 29th November, 1890 : — “ Gresham Angling Society. — There was a good attendance again on Tuesday, with Mr. Vail in the chair. This being a { Microscopical Evening,’ Dr. Brunton and Messrs. Norman, Parker, and Bentley showed a number of interesting subjects. Among other objects, Dr. Brunton exhibited a hank of so-called silk , sold by City houses for fly- tying, &c. Under the Microscope this proved to be nothing but jute, a fact which explains the frequent breaking away of large fish, aud the consequent loss of tackle, temper, &c.” The Microscope and the McKinley Tariff. — Among numerous ex- amples of the mischievous working of the McKinley tariff, the New York 1 Nation ’ cites the instance of Microscopes. Since the branch of medical science known as bacteriology assumed so much prominence, these articles have risen in the United States from the rank of a toy to that of the most valuable anil important of all medical instruments. Meanwhile a foolish legislature has been doing its best to make Micro- scopes artificially dear, and more and more difficult to procure. It was bad enough before the new tariff ; but it is now worse. In spite of the touching appeals of eminent medical men, a Microscope which could be bought in Germany for 94 dollars now costs in America over 150 dollars. This is but one of many examples given of how the tariff is felt to be affecting the vital interests of the American people. £. Technique.* Cl) Collecting Objects, including Culture Processes. Experiments on Cultivation Media for Infusoria and Bacteria.f — In his experiments with anthrax, Dr. Hafkine obtained varying results ; thus when cultivated in the aqueous humour of rabbits, guinea-pigs, or dogs, sometimes copious development occurred, but sometimes it alto- gether failed. When sown with typhoid bacillus the inhibitive action of the humour was very manifest, reducing the number of viable bacilli from 1880 to 7 in four hours. This result is explained by the author on the supposition that the bacilli, which had been cultivated for a long time in pepton bouillon, had not yet become acclimatized to the new medium. For by gradually adding an increasing amount of aqueous humour to the pepton bouillon, in twelve successive generations a strong in- crease in fresh humour was eventually obtained, indeed it was greater than in the bouillon. Control experiments made with bacilli obtained directly from a typhoid patient, behaved in a manner analogous to the artificial * This subdivision contains (1) Collecting Objects, including Culture Pro- cesses; (2) Preparing Objects; (3) Cutting, including Imbedding and Microtomes ; (4) Staining and Injecting ; (5) Mounting, including slides, preservative fluids, &c. ; (6) Miscellaneous. f Annales de l’lnstitut Pasteur, iv. (1890) p. 363. See Centralbl. f. Pakteriol. u. Parasitenk., viii. (1890) p. 435. 1891. K . 130 SUMMARY OF CURRENT RESEARCHES RELATING TO cultivations in aqueous liumour. The germicidal action of the humor aqueus is explained conformably to the ideas of Metschnikoff, with whom the author is working, as being entirely due to an imperfect adaptation to the new medium. Silicic Acid as a Basis for Nutrient Media.* — Prof. W. Kiihne employs silicic acid as a basis for nutritive media which will bear prolonged exposure to high temperatures, and which have the further advantages of resisting the action of organisms and reagents. To make the compound, the author mixes, with frequent shaking, three parts of commercial silicate of soda (sp. gr. 1*08) and one part dilute hydro- chloric acid (HOI sp. gr. 1 * IT one part, and water two parts). The mixture is then freed, in a dialyser, from free acid and from sodium chloride, by suspending the dialyser for four days in a stream of running water. The pure solution is then condensed to a specific gravity of 1 * 02 by heating it in a platinum vessel. In this condition it contains 3*4 per cent, pure acid, is as thin as water, can be boiled, is miscible with alcohol, and only coagulates on addition of neutral salts. The nutrient addendum employed by the author was meat-extract : a piece of Liebig’s extract about the size of a bean is dissolved in 22 ccm. of water, and of this solution 0*5 to 1 ccm. is added to 4 ccm. of silicic acid. If it be desired to set it quickly some cooking salt must be added. Thus obtained the jelly is of the proper consistence, transparent as glass, and scarcely coloured by the meat-extract. It bears the addition of sugar, glycerin, &c. Pure Cultivations of Green Unicellular Algae. | — M. W. Beyerinck has obtained pure cultivations from two species, Chlorococcum proto- genitum Babenh. and Rhaphidium naviculare sp. n., which are frequent in stagnating water near Delft. The author succeeded in getting rid of the numerous water bacteria by the following method: — Ditch water was boiled up with 10 per cent, gelatin, and before setting was mixed with a drop of the water coloured green by the algae. In this mixture only those bacteria which liquefy gelatin could develope. The number of such colonies may be few enough not to liquefy the whole of the gelatin in two or three weeks. With a hand-lens the algar colonies may then be recognized as dark green points. These can then be distributed to fresh gelatin and so pure cultivations obtained. Rhaphidium was found to excrete a trypsinoid ferment which liquefied gelatin. It multiplied by fission. Chlorococcum does not liquefy gelatin, and was cultivated on seven different nutritive media with a neutral or slightly acid reaction. Development in all the seven media proceeded at about the same pace, but the colour of stroke cultivations was very different. In sterilized ditch water with 1 per cent, gelatin previously liquefied by pancreas, the growth advances well, and after three or four weeks there results a yellow fluid with a dark green sediment of Chlorococcum. * Zeitschr. f. Biologie, xxvii. n.s. ix. (1890) No. 1. Cf. Centralbl. f. Bakteriol. u. Parasitenk., viii. (1890) pp. 410-11. t ‘ Aanteekeningen van het verhandelde in de sectie-vergaderingen van het Provinciaal Utreehtsch Genootscbap voor kunsten en wetenschappen gehouden den 25 Juni 1889/ pp. 85-52. Cf. Centralbl. f. Bakteriol. u. Parasitenk., viii. ( 1890) pp. 460-2. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 131 By mixing this sediment with liquefied gelatin, and pouring it into test- tubes, or flattening it out between two glass plates, an equally coloured green cast or plate is obtained which serves excellently for studying the action of light on chlorophyll and the excretion of oxygen. Fig. 11. Flat Flask for cultivating Micro-organisms.* — Dr. J. Petruschky has devised a convenient apparatus for cultivating micro-organisms on the plate or surface principle. It is merely a flat flask, and is made in two shapes. Shape A is made of thin lamp-glass, and the B shape of thick or plate glass. Both have pretty much the same form; that is, they are flat and some- what triangular, or rather like a flat worm. Their general aspect is seen from the illustrations, which give a front and side view, and also the view down the neck when looked at from above. There is a slight difference in the measurements ; those of the A pattern being, height 10-11 cm., breadth 5J-6 cm., width (same measurement as neck) about 1J cm. In the neck there is a circular indentation. The measurements of the B pattern are, height 12*5 cm., breadth 6 cm., width (same as neck) 2 cm. In this pattern the indentation is confined to the broad side of the neck. The A pattern is more suitable for delicate work, such as the dif- ferentiation of typhoid colonies, while the B form suffices for isolation, enumeration, and inoculation purposes. These flat flasks are specially adapted for the bacteriological examination of water, and for the cultivation of anaerobic microbes in hydrogen. Apparatus for filtering perfectly clear Agar.j — Dr. J. Karlinski has invented an apparatus for filtering agar, and though it agrees with that devised by Jakobi, differs from the latter in that its intention is, besides obtaining a perfectly clear solution, to prevent the too quick cooling and setting of the medium. The apparatus, seen in section, fig. 12, consists of a tin vessel a , the upper end of which is closed with a perforated caoutchouc plug, and its bottom ends in a tube fitted with a stopcock. The vessel a is surrounded by the vessel 5, made of similar material, and from near the bottom passes out a short closed pipe. The space b * Centralbl. f. Bakteriol. u. Parasitenk., viii. (1890) pp. 609-14 (3 figs.), t T. c., pp. 643-5 (2 figs.). 132 SUMMARY OF CURRENT RESEARCHES RELATING TO is intended to contain hot water, which is heated by means of a spirit- lamp. . In the vessel a is placed a layer of cotton-wool 10 cm. thick, and this is, before using, damped with hot water. The agar solution, made according to J akobi’s formula, is then poured into a, and the aperture closed with the caoutchouc plug, to which is attached the hand-bellows. The agar solution is thus mar!o Fig. 12. p1G< i3 to run out through the pipe at the bottom by means of compressed air, and is allowed to flow into sterilized vessels. The hot- water jacket prevents the agar from cooling too quickly, so that many test-tubes may be filled very easily. Fig. 13 gives an outside view of the whole apparatus. Pure Cultivations of Gonococcus.* — Herren H. von Schrotter and F. Winkler recommend the albumen of plover's eggs as an excellent nutritive medium for easily obtaining pure cultivations of Neisser’s gonococcus. The medium is prepared after the method of Dal Pozzo.f * Mittheil. aus d. Wiener Embryol. Ift3titut, 1890, pp. 29-34. t See this Journal, 1888, p. 1037. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 133 (2) Preparing- Objects. Methods for the Preservation of Marine Organisms employed at the Naples Zoological Station.* — Prof. Playfair McMurrich writes, “ Unfortunately for our students, especially those living inland and depending largely for their knowledge of marine forms upon dried or preserved specimens in museums, the old-fashioned methods of throwing any material which the collector may find into a jar of alcohol without further attention, or else drying it in the sun, are still almost the only ones made use of for the preservation of museum specimens. The result is that the majority of forms which the student has for study are either dried skeletons, or shrivelled up monstrosities giving no idea whatever of the actual appearance of the creatures supposed to be represented by them. How many college museums possess a specimen of coral showing in any recognizable form the polyps by which the skeleton coral was formed? Or how many have even a satisfactorily prepared Lamelli- branch ? There are, however, in this country, a few collections which show a marvellous improvement in their manner of preparation, and which have been purchased from the Naples Zoological Station, whose conservator, Salvator Lo Bianco, has for several years been devoting himself to the discovery of the best methods for the preservation of the form and colour of the marine animals occurring in the Mediterranean. Until the present, however, his discoveries have not been made common property, except in the few cases where most successful methods for preserving certain forms have been published in connection with accounts of their structure. The last number of the Naples ‘ Mittheilungen/f however, contains a full description, by Lo Bianco, of the methods found most successful for the preservation of the various forms which occur at Naples, and which are undoubtedly applicable to the similar forms found upon our own coast. An abstract of these methods is given in the following pages, in the hope that they may be found useful by the museum curators of this country, and that their application may result in the much-needed improvement of the appearance of the specimens found in the majority of the college museums. It must be fully understood, however, that much depends upon the skill of the preparator, and that want of care and patience will frequently counteract all the advantages to be derived from a good method. All who have had the opportunity of examining specimens prepared by Lo Bianco can appreciate readily the great advantages which may result from the careful application of his methods, and can perceive how greatly we are indebted to him and to Prof. Dohrn for their publication. Alcohol is, of course, indispensable as preservative fluid, but certain precautions are necessary in its use. Except in a very few cases it is unnecessary to use it in its full strength, 70 per cent, being quite sufficient for preservation, and producing much less contraction and fragility in delicate organisms. Strong alcohol should be reduced with distilled water to the desired strength, ordinary spring water frequently contain- * Amer. Natural., xxiv. (1890) pp. 856-65. t See Mittheil. Zool. Stat. Neapel, ix. (1890) pp. 485-74. 134 SUMMARY OF CURRENT RESEARCHES RELATING TO ing a sufficient amount of carbonate of lime and other substances in solution to give a cloudy precipitate, after a time, which may effectually destroy the appearance of a specimen. Furthermore, delicate organisms should first be placed in weak alcohol (35 to 50 per cent.) for from two to six hours, the changing of the fluids being effected by a siphon, a small quantity of the weak alcohol being withdrawn and stronger added, until finally the desired strength is obtained. With delicate gelatinous structures the increase in the strength of the alcohol should be as gradual as possible. In many cases it is necessary to use a hardening or fixing reagent before the final consignment to alcohol, which is principally useful as a pre- servative. The most fixing reagents, according to Lo Bianco, are the following : — Chromic acid. — 1 per cent, in fresh water. Objects should not remain in the fluid longer than is necessary to fix them, as they are apt to become brittle. Subsequently they should be well washed with distilled water to prevent the formation of a precipitate when placed in alcohol, and also to prevent their taking on too green a tinge from the reduction of the acid. Acetic acid, concentrated, kills rapidly contractile animals, but must be used with caution, as it produces a softening of the tissues if they are subjected for too long a time to its action. Osmic acid, 1 per cent, solution, hardens gelatinous forms well, and preserves their transparency, but its prolonged action renders the objects brittle and gives a dark brown tint. Objects hardened in it should be well washed in distillled water before being placed in alcohol. Lactic acid. — 1 part to 1000 parts sea -water fixes larvae and gelatinous forms well. Corrosive sublimate. — Saturated solution in fresh or sea-water; may be used either hot or cold. It acts quickly, and preserves admirably for histological purposes. It is especially good combined with copper sulphate, acetic acid, or chromic acid. Objects hardened in it should be subsequently well washed in distilled water and in iodized alcohol (the recipe for which is given below), to remove all traces of the sublimate, which in alcohol crystallizes out in the tissues of the organisms and so injures the preparation. Bichromate of potassium. — 5 per cent, solution in distilled water hardens gelatinous organisms slowly, without rendering them fragile. It gives, however, a precipitate in alcohol, and discolours the specimen. The discoloration, however, may be removed by adding to the alcohol a few drops of concentrated sulphuric acid. Copper sulphate. — 5 per cent, or 10 per cent, solution in distilled water, used either alone or in combination with corrosive sublimate, kills larvae and delicate animals without distortion. The objects should be subsequently repeatedly washed with water to remove all traces of the salt, otherwise crystals will form when the object is placed in alcohol. Various combinations of these reagents are especially useful, and some of those most serviceable are given here : — Alcohol and chromic acid. — 70 per cent, alcohol, 1 per cent, chromic acid, equal parts. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 135 Alcohol and hydrochloric acid. — 50 per cent, alcohol, 100 ccm. ; Hydrochloric acid, concentrated, 5 ccm. Iodized alcohol.— 35 per cent, or 70 per cent, alcohol, 100 ccm.; Tincture of iodine, 2 * 5 ccm. Chrom-acetic acid, No. 1. — 1 per cent, chromic acid, 100 ccm. ; Concentrated acetic acid, 5 ccm. Chrom-acetic acid, No. 2. — Concentrated acetic acid, 100 ccm. ; 1 per cent, chromic acid, 10 ccm. Chrom-osmic acid. — 1 per cent, chromic acid, 100 ccm. ; 1 per cent, osmic acid, 2 ccm. Chrom-picric acid. — 1 per cent, chromic acid, Kleinenberg’s picro- sulphuric acid, equal parts. Copper sulphate and corrosive sublimate. — 10 per cent, solution of copper sulphate, 100 ccm. ; saturated solution of corrosive sublimate, 10 ccm. Potassium bichromate and osmic acid. — 5 per cent, solution of potassium bichromate, 100 ccm. ; 1 per cent, osmic acid, 2 ccm. Corrosive sublimate and acetic acid. — Saturated solution of corrosive sublimate, 100 ccm. ; concentrated acetic acid, 50 ccm. Corrosive sublimate and^ chromic acid. — Saturated solution of chromic sublimate, 100 ccm. ; 1 per cent, chromic acid, 50 ccm. Frequently great difficulty is experienced in killing an animal without producing a considerable amount of contraction, and in the case of elongated forms, such as Nemerteans and other worms, without causing them to coil up or become twisted, To avoid this, it is ex- pedient to narcotize the animals before killing them, and for this purpose Lo Bianco recommends immersion in weak alcohol. He uses generally a mixture of sea-water 100 ccm. and absolute alcohol 5 ccm. In other cases 70 per cent, alcohol may be carefully poured upon water in which the specimen lies, so that it forms a layer at the surface. It will gradually mix with the subjacent water, and in the course of a few hours will narcotize the animal, so that it may be treated with fixing reagents without fear of contraction. Chloral hydrate, 1 to two parts sea-water, is also efficient as a nar- cotizing agent, and has the advantage of allowing a recovery of the animal, if there should be necessity for it, by placing it in fresh sea-water. For some sea-anemones tobacco smoke is useful, the smoke being conducted by a Y-shaped tube into a bell-jar covering the vessel of sea- water in which is the anemone. Certain of these reagents will prove most satisfactory with some animals, others with others. Lo Bianco details the best method for treating the various forms in a second portion of his paper, and an account of some of his methods of procedure, so far as they concern forms which resemble those found upon our coast, may now be presented. Sponges. — Direct immersion in 70 per cent, alcohol, with subsequent renewal of the fluid, is recommended for the majority of forms. To avoid contraction in the case of the Halisarcidae, they should be left for half an hour in 1 per cent chromic acid, or in concentrated solution of corrosive sublimate for fifteen minutes. To prepare dried specimens the sponges should be washed in fresh water for a few hours, and then allowed to remain in ordinary alcohol for a day, after which they may be dried in the sun. 136 SUMMARY OF CURRENT RESEARCHES RELATING TO Anthozoa. — The first care must be to place the forms belonging to this group in fresh salt water, to allow them to expand, a result which may not be obtained until the following day in some cases. Alcyona- rians should be killed with chrom-acetic solution No. 2, withdrawing the water in which they lie, until there is left just enough to cover them, and then adding a volume of the chrom-acetic solution double that of the sea-water. The animals should be removed from this mixture the moment they are killed, since the acid will quickly attack the calcareous spicules, which are important for the identification of the Alcyonaria, and placed in 35 per cent, or 50 per cent, alcohol, it being well to inject the alcohol into the mouths of the polyps to keep them freely expanded. The preparation should finally be preserved in 70 per cent, alcohol. Regarding the Actinians no definite rule for preservation can be given. Much of the success of the preparation depends on the form employed, some species contracting much less readily and less perfectly than others. Some may be killed in a fair condition by pouring over them boiling corrosive sublimate, and then, before consigning them to alcohol, treat- ing for a few minutes with one-half per cent, chromic acid. This method may be employed with small forms such as Aiptasia. Narcoti- zation may be tried with others. For this purpose, remove from the vessel in which the animals are contained, two-thirds of sea-water, and replace it with a 2 per cent, solution of chloral hydrate. After a few minutes the fluid is again removed, and cold concentrated sublimate solution is poured in. Tobacco smoke in some cases, as with Adamsia, will act satisfactorily, if followed with vapour of chloroform for two to three hours, after which the animals may be killed in chrom-acetic solution No. 2, and hardened in one-half per cent, chromic acid. Edicardsia may be narcotized by gradually adding 70 per cent, alcohol to the sea-water in which they are, and subsequently may be killed with hot corrosive sublimate. Cerianihus should be killed with concentrated acetic acid, placing it as soon as possible in weak alcohol, in which it should be suspended, so that the tentacles may float freely — if necessary, disentangling them. Corals should be allowed to expand fully, and should then be killed with boiling solution of corrosive sublimate and acetic acid used in volume equal to that of sea-water containing the coral. The colony should then be transferred to 35 per cent, alcohol, some of this fluid being injected into the mouth of each polyp. The injection should be repeated at every change of the alcohol, and the specimens should be preserved in 70 per cent, alcohol, after washing them well in iodized alcohol. Hydromedusae. — For the hydroid colonies the best fixing reagent is hot corrosive sublimate. The smaller Tubularian medusae should be killed either in the mixture of corrosive sublimate and acetic acid, or in Kleinenberg’s picrosulphuric acid. Larger forms may be fixed with concentrated acetic acid, and then allowed to fall imto a tube containing the alcohol and chromic acid mixture, in which they are gently agitated and allowed to remain for fifteen minutes, after which they should be transferred to 35 per cent, alcohol, and gradually carried to 70 per cent. Small Campanularian medusae, e. g. Eucope and Obelia, may be killed in the mixture of copper sulphate and corrosive sublimate. jEquorea ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 137 should be killed with concentrated acetic acid, and immediately trans- ferred to chrom-osmic mixture for fifteen to thirty minutes. The same method answers for Cunina, while Liriope should be treated at once with chrom-osmic from five to twenty minutes. Scyphomedusfe are the best fixed with 1 per cent, osmic acid, to the action of which they are subjected until they assume a pale brown tint. They should then be thoroughly washed with fresh water before being placed in 35 per cent, alcohol, and should be finally preserved in 70 per cent. Siphonophores. — The forms of this group should be preserved soon after capture, and specimens in good condition should be selected. Agalma and similar forms should be killed in the mixture of copper sulphate and sublimate, which should be used in volume equal to or double that of the sea-water in which the animal floats. The mixture should be poured in rapidly, and not over the animal. When killed, the specimen should be carefully lifted upon a large horn spatula, and transferred to 35 per cent, alcohol for a few hours, and then placed in 70 per cent. It is recommended to preserve the animals in tubes just large enough to contain the specimens, and placed within a second larger tube. In this way evaporation of the alcohol is prevented, and also injury of the specimen from movements of liquid is avoided. Physalia should be placed in a cylinder filled with sea-water, the animal being lifted by the pneumatophore. When well expanded, it is killed by pouring over it the sublimate and acetic acid mixture (one- quarter the volume of the sea-water), and when dead, is transferred to a cylinder containing one-half per cent, chromic acid, and then after twenty minutes to 50 per cent, alcohol, and finally to 70 per cent. Velella may be killed with chrom-picric or sublimate and chromic acid mixture, and after a few minutes should be transferred to weak alcohol. Porpita may be fixed by dropping Kleinenberg’s picro-sulphuric acid into the vessel in which it is contained, and when the blue colour commences to change to red it should be transferred to Kleinenberg’s fluid, and after fifteen minutes to weak alcohol. Diphyes may be killed expanded by hot corrosive sublimate. Ctenophora may be killed by throwing them into the chrom-osmic mixture, where they should remain for fifteen to sixteen minutes, accord- ing to the size, and then gradually passing them through alcohol to 70 per cent. A mixture composed of pyroligneous acid, concentrated, 1 vol. ; corrosive sublimate solution, 2 vol. ; one-half per cent, chromic acid, 1 vol., is also recommended as a fixative. Echinodermata. — Starfish may be prepared with the ambulacral feet in full distension by allowing them to die in 20 to 30 per cent, alcohol. Echinoids should be placed in a small quantity of water, and killed with chrom-acetic mixture No. 2, being removed from it as quickly as possible, as the acid corrodes the test. To preserve the internal parts it is necessary to make two opposite openings in the test, so that the alcohol may penetrate the interior readily. Holothurians, such as Thyone and Cucumaria, after the tentacles are fully expanded, should be seized a little below the bases of the tentacles by forceps, using a slight pressure, and the anterior portion of the body should then be immersed in concentrated acetic acid. Alcohol (90 per 138 SUMMARY OF CURRENT RESEARCHES RELATING TO cent.) should then be injected into the month, and the specimens placed in 70 per cent, alcohol. The injection should be repeated each time the alcohol is changed. Syjmpta should be fixed by immersion in a tube containing a mixture of equal parts of sea-water and ether (or chloroform), where they remain completely expanded. They should then be washed for a short time in fresh water, and passed into alcohol, taking care to increase the strength of this very gradually. Vermes. — Cestodes, Trematodes, Turbellaria, as well as Nemathel- minths, are most satisfactorily killed with corrosive sublimate, either cold or hot. Sagitta, however, succeeds best in copper sulphate and sublimate or chrom-osmic mixture. Nemerteans should be narcotized in a solution of chloral hydrate in sea-water 1 per cent., where they should remain for six to twelve hours. They are then to be hardened in alcohol. Gephyreans may be narcotized with 1 per cent, solution of chloral hydrate in sea-water, or in alcoholized sea-water, three to six hours ; or may be killed at once in one-half per cent, chromic acid, which last method may be also applied to Hirudinea. Chaetopods are best narcotized in sea-water containing 5 per cent, of absolute alcohol, or by adding gradually to the snrface of the sea-water in which they are contained a mixture of glycerin 1 part, 70 per cent, alcohol 2 parts, and sea-water 2 parts, hardening them subsequently in alcohol. Chwtopterus is best killed with 1 per cent, chromic acid, in which they should remain for half an hour ; while the Hermellidae, Aphroditidae, and the Eunicinse may be killed in cold corrosive sublimate. Some of these, such as Diopatra, may, however, be narcotized in alco- holized sea-water. Serpulidae, before treatment with corrosive sublimate, should be narcotized in 1 per cent, chloral hydrate, which causes them to protrude wholly or partly from their tubes. Crustacea. — Cladocera, Copepods, and Schizopods may be killed in corrosive sublimate dissolved in sea-water. Ostracods may be thrown at once into 70 per cent, alcohol. Cirripeds die expanded in 35 per cent, alcohol, and if some specimens contract it is easy to draw out the cirri with forceps. Amphipods and Isopods may pass directly into 70 per cent, alcohol, except the Bopyrids and Entoniscids, which should be killed in the mixture of equal parts of 90 per cent alcohol and sublimate solution. To avoid the casting-off of the appendages of the Decapods they should be allowed to die in fresh water, care being taken not to allow them to remain in it longer than is necessary, as it causes a distortion of the membranous appendages. Pycnogonids will die in one-half per cent, chromic acid, with the appendages fully extended. Mollusca. — Lamellibi anchs, Prosobranchs, and Heteropods should be narcotized in alcoholized sea-water. To avoid the closure of the valves of Lamellibranchs on immersion in 70 per cent, alcohol, little plugs of wood should be placed between the margins of the valves. The same result may be effected in the case of Prosobranchs by tying the internal edge of the operculum to the shell. Of the Opisthobranchs the HDolidae may be the best preserved by ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 139 pouring over them concentrated acetic acid in volumes equal to or double that of the sea-water containing them. Dorids should first he narcotized by gradually adding 70 per cent, alcohol to their sea-water, and then killed with concentrated acetic acid or boiling sublimate. The larger forms may be killed in 1 to 5 per cent, chromic acid. Pteropods are preserved well in Perenyi’s fluid for 15 minutes, whence they are passed to 50 per cent, alcohol. Gymnosomatous forms should be first narcotized with 1 per cent, chloral hydrate, and then killed in acetic acid or sublimate. Decapod Cephalopods may be fixed directly in 70 per cent, alcohol, making an opening on the ventral surface to allow the alcohol to reach the internal parts. Bryozoa. — The genera Pedicellina and Loxosoma may be left for an hour in 1 per cent, chloral hydrate, and then killed with cold corrosive sublimate, washing them immediately afterwards. Some species of Bugula give good results when the expanded animals are suddenly killed by pouring over them hot corrosive sublimate. With other forms it is sometimes possible to preserve them well expanded by adding 70 per cent, alcohol gradually to the surface of the water in which they are, or by narcotizing first in weak chloral hydrate or in alcoholized sea-water. The results are, however, uncertain, and depend largely on the skill of the preparator. Brachiopoda may be treated in the same manner as Lamellibranchs. Tunicates. — Clavellina , Perophora , and Molgula may be killed with the orifices expanded by immersing them in 1 per cent, chloral hydrate for 6 to 12 hours. They should then be killed in chromic-acetic mixture No. 2, and quickly transferred to 1 per cent, chromic acid, injecting some of the fluid into the body. After half an hour they should be transferred to 35 per cent, alcohol, the injection being repeated, and finally to 70 per cent. Other simple forms may be treated in the same manner, or may require the 2 per cent, solution of chloral hydrate, or may be killed by pouring a little 1 per cent, chromic acid on the surface of the water in which they are, subsequently hardening in 1 per cent, chromic acid. The method recommended for Perophora may be employed for compound Ascidians, using, however, corrosive sublimate instead of the chrom-acetic mixture. Salpee vary considerably in consistency, according to the species, and different methods are consequently required. The denser forms, such as S. zonaria , should be placed in a mixture of 100 ccm. fresh water and 10 ccm. concentrated acetic acid, where they should remain for 15 minutes. They should then be washed in fresh water for 10 minutes, and pass gradually into alcohol. Less dense forms such as S. democratica mucronata , may be fixed in chrom-acetic mixture No. 1, and then passed directly into fresh alcohol ; while the soft forms such as S. pinnata and maxima , should be placed in chrom-osmic mixture for 15 to 60 minutes, then washed in fresh water, and transferred to weak alcohol. Fishes. — Amphioxus will die with the buccal cirri distended in sea- water alcoholized to 10 per cent. They should then be transferred to 50 per cent, alcohol, and gradually to 70 per cent. Other forms may be preserved in alcohol (70 per cent.), taking care to make a ventral incision, and also to inject the alcohol and renew it 140 SUMMARY OF CURRENT RESEARCHES RELATING TO frequently at first. If it is wished to preserve some of the larger Selachians for some months in order to prepare at leisure the skeleton, the intestines should be removed, and the animals placed in a 10 per cent, solution of salt. Elasmobranch embryos may he fixed in corrosive sublimate, leaving them in the solution for 5 to 15 minutes, afterwards washing well in iodized alcohol. Embryos of Torpedo with the yolk were preserved by immersing them in a mixture of equal parts of 1 per cent, chromic acid and corrosive sublimate for 15 minutes, and then transferring to alcohol. Transparent fish-eggs may be preserved for the purpose of demonstration by subjecting them for a few minutes to the action of the alcohol and hydrochloric acid mixture, and then transferring them to pure alcohol. Some Hints on the Preparation of Delicate Organisms for the Microscope.* — Mr. E. Lovett observes that such organisms as the ova of Mollusca, Crustacea, fishes, &e., are often of such a nature as to be very difficult of permanent preservation, but he has succeeded in overcoming the difficulty satisfactorily by means of a fluid, the density of which he modifies in accordance with the organism about to be mounted. The fluid was composed as follows : — Three parts pure alcohol, two parts pure glycerin, and one part distilled water. This strength was suitable for young crustaceans, the ova of the fishes, and for the tougher ova-sacs of the Mollusca. For the ova of crustaceans and insects, and for those of very small fishes, one or two parts more of distilled water may be added ; whilst for such exceedingly delicate substances as the ova of the nudibranchiate Mollusca, zoophytes extended from their capsules, and for various delicate fresh-water forms, a weaker formula than this is necessary ; but as practice is the best instructor, he recommends students to be guided by what they find to be the best proportions. This fluid should be put into small glass tubes, with corks bearing numbers corresponding to those in a note-book, so that full details of the contents may be recorded. These tubes should be taken down to the shore by the collector, and the organisms should be placed therein alive, direct from the sea. The length of time required for the pre- servation of the object by the fluid varies, according to the organism, from a week to a year, but some of Mr. Lovett’s best preparations had been soaking, before being mounted, for five or seven years ; and as a proof of the value of the preservative fluid, he cites the mucus-like ova mass of an Eolis, which was in quite its natural condition, although eight years of age as a micro-slide. The cement used by Mr. Lovett for fixing cells for this fluid, for fixing the cover-glasses to the cell-wall, or for covering sunk cells, is composed of equal parts of red lead, white lead, and brown litharge, pounded to a powder and kept dry. When wanted for use, a little is mixed with japanner’s gold size as thick as required, and it must be used with great care to insure success ; but in this case also practice is the best way to satisfactory results. Improved Method of preparing Ascidian Ova-t — Dr. T. H. Morgan found that the ordinary methods of preparation do not show the boun- daries of the cells of the follicle in sections of young ova. He made, * Trane. Croydon Micr. and Nat. Hist. Club, 1889-90, pp. 203 -4. t Journal of Morphology, iv. (1890) p. 198. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 141 therefore, various experiments, and found the following method satis- factory. The fresh ovaries were teased apart in very dilute osmic acid, washed in distilled water, and placed in a 1 per cent, solution of silver nitrate, where they remained for half an hour ; they were then put into acetic acid for the same length of time, and placed in the sunlight. On examination under the Microscope the cell-boundaries were distinctly seen. Simple Method of examining living Infusoria.* — Herr J. Eismond has discovered a method of slowing those rapid movements of Infusoria which make the examination of these objects during life so difficult. The method is based on that of crystallographers, who retard the forma- tion of crystals by the addition of a colloidal material. He added a drop of thick watery solution of cherry-gum, and obtained the desired effect. In a very short time the Ciliata were seen to be imprisoned, with all their cilia moving actively, but effecting no change in position. All the vital processes can be most satisfactorily observed in Infusoria so treated, and a certain amount of locomotion can be allowed by using a less dense solution. Small Crustacea, Worms and Flagellata, and other marine animals, may be well studied by this method. It may be added that gum-arabic and other fixing materials are useless. New Method for demonstrating Tubercle Bacilli in Sputum.f — Dr. E. Czaplewski recommends the following method which he says gives ideal pictures in about three minutes of tubercle bacilli in sputum. Three solutions are required : — (1) The Ziehl-Neelsen carbolic-fuchsin. (2) Saturated alcoholic solution of yellow fluorescin to which methylen- blue is added to excess. (3) Saturated alcoholic solution of methylen- blue. A very thin layer of sputum must be fixed on the cover-glass in the usual manner. On the cover-glass held in a pair of forceps, sputum side upwards, is then let drop sufficient of the fuchsin solution to form a complete layer. It is then held over the flame of a spirit-lamp until it vaporizes or begins to boil. The fuchsin is then run off and the cover- glass waved to and fro in the fluorescin solution six to ten times, and aiter this in the methylen-blue solution ten to twelve times. The cover- glass is next quickly washed in pure water and then at once laid with the prepared surface upon a clean slide. The superfluous water is then expressed by means ot a piece of blotting-paper placed on the top, and any deposit of pigment removed with a moist cloth. Finally, a drop of cedar oil is laid on the back. The preparation is then ready for examination. Hence it will be seen that the organisms are observed in water, but the preparation may of course be mounted in the usual manner. Method for Differential Diagnosis of Bacilli of Typhoid (Eberth)4 — The procedure consists in a modification by J. Gasser of Noeggerath’s method for recognizing the typhoid bacillus. To a test-tube full of nutrient agar twenty drops of a saturated aqueous solution of fuchsin are added, the mixture sterilized and poured into a Petri’s * Zool. Anzeig., xiii. (1890) pp. 723-4. t Centralbl. f. Bacteriol. u. Parasitenk., viii. (1890) pp. 685-94. X La Semaine Med., 1890, No. 31. Cf. Bakteriol. u. Parasitenk., viii. (1890) p. 411. 142 SUMMARY OF CURRENT RESEARCHES RELATING TO capsule. When set the surface is scratched with the bacillus and then incubated at 37°. In four hours the cultivation has developed, the agar round about it being decolorized. The whole plate has lost its colour in six to eight days, but the cultivation itself is quite red. Control experiments with numerous other micro-organisms showed that typhus bacillus and B. coli communis were the only two which decolorized the medium. It is said that the two may be distinguished by the fact that B. coli comm, does not exceed the inoculation track, while typhus bacillus forms a broader strip with irregular margins. New Criterion for distinguishing between Bacillus Cholerse Asia- tic® and the Finkler-Prior Bacillus.* — If these two bacilli, say Herren O. von Hovorka and F. Winkler, be cultivated on plover’s egg albumen they may easily be distinguished. The Finkler-Prior bacillus rapidly liquefies, and imparts a yellow colour to the medium, while Koch’s comma bacillus neither liquefies nor stains it. This difference is clearly distinguishable in the first six days of the cultivation. Reference Tables for Microscopical Work.j — Professor A. B. Aubert has compiled the following tables which have been in great part translated and adapted from Dr. Behrens' c Tabellen zum Gebrauch bei Mikroskopischen Arbeiten.’ They address themselves especially to workers in the various departments of microscopy where such aids to the memory may be helpful in everyday work. The methods given are such as have received the approval of many of the best workers at home and abroad. A glance at the tables will generally give all the information necessary to any one fairly familiar with micro-manipulation, and while they do not aim at replacing the larger and more complete works, it is hoped that they will prove useful on the work-table of microscopists generally. Preservative and Mounting Media : — Alcohol-glycerin. — Glycerin, 1 part ; alcohol (96 per cent.), 1 part ; water, 1 part. Specially recommended for plants, entire or in parts. Canada balsam in alcohol, chloroform, benzol, turpentine, xylol. — The balsam is hardened by low heat until brittle when cold, broken up or pulverized, dissolved in the solvents, filtered through paper, and evaporated until of the thickness of syrup. Boroglyceride. — Dissolve as much boracic acid in warm glycerin as possible. The solution is thick when cold; use for mounting some animal or plant preparations in the same way as balsam. Canada balsam : — The thick balsam is heated, and the mounting done on the warm table ; the object must first be soaked in absolute alcohol, then in oil of cloves. Glycerin and carbolic acid : — Glycerin, 100 grm. ; absolute alcohol, 50 grm. ; water, 50 grm. ; carbolic acid, 3 grm. For plant sections, &c. Chloride of calcium concentrated, or 33, 25, 12 per cent. For vegetable preparations, &c. Dammar: — Dissolve gum dammar in equal parts of benzol and turpentine ; the solution is filtered and evaporated to syrupy thickness. * Mittheil. aus d. Embryol. Institute der K. K. Univ. Wien, 1890, pp. 10-14. t Micr. Bull, and Sci. News, vii. (1890) pp. 35-6. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 143 Farrant’s medium : — Gum arabic, 1 ounce ; glycerin, 1 ounce ; water, 1 ounce ; arsenious oxide, 1J grains. Dissolve the oxide in water, then the gum, without heat ; when entirely dissolved add the glycerin, take care not to form bubbles; can be filtered through fine flannel. Specially recommended for delicate plant or animal tissues. Glycerin : — Concentrated or diluted with water, to which may be added a few drops of acetic or carbolic acid. For vegetable and animal preparations. Glycerin-jelly: — Glycerin, 120 grm. ; water, 60 grm. ; gelatin, 30 grm. Dissolve the gelatin in warm water, add the glycerin, filter, if necessary, through flannel. All forms of glycerin-jelly must be used warm. For vegetable and animal tissues. Deane’s medium : — Similar to glycerin-jelly but with the addition of honey and a small quantity of alcohol. Used in place of glycerin-jelly. Glycerin-salicylic vinegar : — Glycerin, 1 vol. ; water, 4 vol ; salicylic vinegar, 0*1 vol. For Infusoria. Glycerin-salicylic vinegar for larvae, Hydra , Nematodes, &c. : — Glycerin, 1 vol.; water, 2 vol.; salicylic vinegar, 0*1 vol. Salicylic vinegar is made by dissolving 1 part salicylic acid in 100 parts pyro- ligneous acid, sp. gr. 1 * 04. Goadby’s medium : — Corrosive sublimate, 0*25 grm. ; alum, 60 grm. ; boiling water, 2300 grm. (3) Cutting-, including: Imbedding: and Microtomes. Imbedding Seeds by the Paraffin Method.* — Mr. W. W. Rowlee writes : — “ The modifications that may be made of the paraffin method of imbedding objects for sectioning are very many. There is always, however, some danger of shrinking delicate and very soft plant tissue. This is due to the use of heat in the process of infiltration ; and probably some of the non-heat-employing methods will be found preferable where such delicate tissue is to be imbedded. But for objects that will with- stand this process of infiltration, the paraffin method has many advan- tages over others. Imbedded in paraffin, objects are held firmly, and may be preserved as long as desired without further attention. For imbedding mature seeds I have found nothing equal to paraffin. The texture of the seed is often very dense, and offers much resist- ance to the knife. For this reason I found it better to use the harder grade of paraffin. A second serious difficulty that was met with in imbedding seeds was the fact that there was little, if any tissue con- necting the embryo j- with the seed-coats. Thus it would happen too often that just as the sections were being taken through the middle of the seed — and the most valuable ones are those near the centre — the embryo would leave the coats and the whole series would be spoiled. The inner surface of the inner coat in many seeds is highly polished, and as soon as there is nothing to retain the embryo but its adhesion to the coat, it will loosen. The paraffin does not hold the two together as would be expected. It was suggested that, in order to soften the tissue * Amer. Mon. Micr. Journ., xi. (1890) pp. 228-30. f The term “ embryo ” is used here where on some accounts it would be better to use the word “ nucleus.” The embryo is often but a very small part of the substance contained within the seed-coats. 144 SUMMARY OF CURRENT RESEARCHES RELATING TO and thereby make it more susceptible of infiltration, it would be well to thoroughly soak the seeds in water before hardening in alcohol. This was tried, and there was a great improvement in the results. Fewer of the sections went to pieces after they were transferred to the slide, and the parts of the seed kept their respective positions much better. In order to study the microscopic structure of seeds, much more satisfactory results can be obtained if the sections are kept in series. It is often necessary to have two or more successive sections before a correct idea of the seed can be obtained. The method is a modification of the one used and taught in the histological laboratories of Cornell University. In its practical appli- cation it is as follows : — In choosing seeds to section, great care is taken to get those which are well filled. This precaution is especially im- portant, as many seeds, for various reasons, never develope more than the coats or the enveloping ovary coats. If a seed has a straight embryo, or even a bent or curved one, it is better to determine by dissection just how the parts of the embryo are arranged with reference to the external parts of the seed. Thus, the seeds of Helianthus tuberosus are flat- tened, and slightly wedge-shaped. The embryo within is straight, and the upper or inner surface of the cotyledons lie in a plane parallel to the plane in which the seed is flattened. Moreover, the cotyledons are in the upper broader end of the seed. Where the seed has no external character, as in a Eupatorium , by which the position of its internal parts may be located, one has either to take the chances of getting the sections in the right plane, or open the coats enough to see how the parts are arranged, and then mark the seed in some way. Having selected a well-filled seed, I next put them in water at the ordinary temperature of the laboratory from 24 to 36 hours. From the water they are trans- ferred to weak alcohol (40 per cent.), and gradually hardened by trans- ferring to stronger until they are in 95 per cent, alcohol. Schultze’s apparatus may be used to advantage in hardening. Next transfer to equal parts of alcohol and chloroform for from 4 to 8 hours, the time depending on the size of the seeds. Then in pure chloroform for the same length of time. Then for 24 hours into chloroform with as much paraffin in it as it will dissolve at the ordinary temperature. From this into paraffin softened with chloroform, the melting-point of which is about 36° 0. The specimens are kept in this melted paraffin 24 hours. I have always been careful not to let the temperature go above 47° C., although I think it probable that a somewhat higher temperature would not injure the tissue of a seed. From this the seed may be imbedded in hard paraffin, and will be found to be thoroughly infiltrated. The seeds may be sectioned in the paraffin blocks either free-hand or with a microtome. It is highly essential that the sections be kept in series, and that none be missing. The texture of a seed is so fragile that when cut in thin sections the least carelessness may spoil a section. A very effectual way to keep sections intact when they are cut in paraffin is that proposed by Dr. Mark.* It consists in collo- dionizing the object as the sections are taken. Very thin collodion should be used, and applied to the cut surface after the section is taken, Lee t recommends that ‘ the collodion be of such a consistency that, * Amer. Nat., 1885, p. G28. f ‘Vade-mecum,’ 2nd ed., p. 150. ZOOLOGY AND BOTANY, MICROSCOPY; ETC. 145 when applied to a surface of paraffin, it dries in two or three seconds. This has no tendency to cause the sections to roll. ... As soon as the collodion is dry, which ought to be in two or three seconds, cut the section, withdraw the knife, and pass the collodionized brush over the newly exposed surface of paraffin.’ The sections are placed collodion side down on the slide. They may be fastened by first painting the slide with a few drops of clove-oil collodion, placing them in it, and then evaporating off the clove oil. The sections are then placed in xylol for 15 minutes. This removes the paraffin. They are then washed in alcohol, afterwards with water, and stained. I have found no stain that was as effective in staining seeds as haematoxylin. They should be stained from 3 to 5 minutes. After washing the staining agent away with water, dehydrate with alcohol, and clear. Three parts of turpentine and two parts of carbolic acid make a very good clearing mixture. Canada balsam dissolved in xylol is used for mounting. In sections thus prepared one can dis- tinguish without difficulty in shepherd’s purse, golden-rod, or any endo- spermous seed, the coats, the plumule composed, as is the lower tip of the radicle, of small thin-walled nucleus-bearing cells. These two regions of growth are connected by slightly elongated cells, which are also thin-walled. The larger cells making up the tissue of the coty- ledons are stored with food. In many seeds a trace of a fibrovascular system may be seen ; also the peculiar arrangement and markings of the cells composing the coats. Seeds differ so much, that one would need to make many variations in method to suit different cases ; but as a general method I have found this to be a success, and I believe the histology of any seed may be demonstrated by applying it.” Microtome.* — Messrs. Bausch and Lomb write: — “We have found that the section-cutters formerly made by us and other manufacturers Fig. 14. 146 SUMMARY OF CURRENT RESEARCHES RELATING TO are in some respects not suited to modern requirements. We have therefore ceased to make such, and have replaced them by new instru- ments, which we shall hereafter class under the head of microtomes. The instrument presented here is dissimilar from the Laboratory and Student microtomes of our manufacture in not having mechanical movement for the knife ; it is intended to be fastened to the table-top by means of thumb-screw. The cutting-plate of the instrument is inlaid with glass to obtain perfect smoothness. To the carriage are directly fitted the micrometer-screw with graduated disc, and a section-clamp which is acted upon by the former. The pitch of the screw is 1/50 in., graduation on disc 10, and the finest degree of feed 1/500 in. The regular section-knives as well as the ordinary razors can be used with the instrument.” C4) Staining- and Injecting-. Brown-staining Bacillus.* — Herr D. Scheibenzuber describes a bacillus which he has isolated from rotten plover’s eggs, and of which the chief characteristic is that it stains the gelatin in the immediate vicinity of the colonies of a brownish colour. The colonies when grown on plates are stated to consist of a central area, which is surrounded by a radiately striated zone. The gelatin surrounding the colonies is not liquefied ; when cultivated in test-tubes (puncture cultivation), the inoculation track becomes characteristically serrated, and produces a brown pigment. When examined with 1/20 oil-immersion the micro-organism is found to be a short bacillus pointed at both ends. New Method for Staining and Mounting Tubercle Bacilli. | — Dr. H. Kiihne recommends the following method for staining tubercle bacilli : — After the cover-glasses have been prepared, that is, coated with sputum and dried in the flame, they are stained in carbolic fuchsin for five minutes. They are then thoroughly decolorized in 30 per cent, nitric or sulphuric acid, and subsequently washed in water and dried. After this they are examined in a drop of anilin oil stained slightly yellow with picric acid. This mixture is best made by adding 2 to 3 drops of concentrated solution of picric acid in anilin oil to a capsule full of anilin oil. Preparations obtained in this way will remain fit for examination for at least a week. If permanent preparations are desired, the cover- glass, after it has been decolorized by the mineral acid, is placed for some minutes in an aqueous solution of picric acid, then dried and mounted in the usual manner. Staining Flagella of Spirilla and Bacilli.j: — Dr. Trenkmann finds that the flagella of bacteria may be stained with very satisfactory results in the following manner : — The cover-glass having been prepared from a cultivation in the usual manner, is immersed for 6 to 12 hours in a solution of 2 per cent. * Mittheil. aus d. Embryol. Institute d. K. K. Univ. Wien, 1890, pp. 1-9 (4 figs.). f Centralbl. f. Bakteriol. u. Parasitenk., viii. (1890) pp. 293-7. X T. c., pp. 385-9. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 147 tannin and 1/2 to 1/4 per cent. HC1. The preparations are next care- fully washed and placed in iodine water. Gram’s iodine or one drop of iodiue tincture to 10 ccm. water does very well, but iodine mixed with water and allowed to stand for 24 hours (shaking frequently) answers better. In the iodine solution the covers remain for about one hour ; they are then washed in water, and stained with gentian-violet. The violet solution is made in a 25 ccm. test-tube. One drop of a saturated alco- holic solution of gentian-violet solution is mixed with 10 ccm. distilled water. Half of this is poured away and the test-tube filled up with anilin water. In this solution the covers remain for about 30 minutes. Afterwards the author advises using a less quantity of hydrochloric acid, and to have three different solutions, viz. : — Two per cent, tannin, with 1, 2, and 3 per 1000 HC1. The 1 per 1000 may be made by mixing 10 grm. of a 2 per cent, tannin solution and 2 drops of 8 per cent. HC1. Impregnation of Bone Sections with Anilin Dyes.* — Herr N. Matschinsky finds that saturated aqueous solutions of anilin pigments are excellent for demonstrating the* growth-appearances of bone. The pig- ments used were eosin, safranin, gentian-violet, methylen-blue, methyl- green, iodide-green, and fuchsin, and though all were satisfactory, eosin and safranin gave the best results. The bones examined were sectioned transversely and longitudinally, and were both macerated and fresh. If fresh, the fat was removed by immersing the sections for half an hour in ether, and after having been polished up, the dust removed, and washed in water, they were trans- ferred to the staining solution. Macerated bones were allowed to remain for about 48 hours, but if kept at a temperature of 40° C., the staining was more rapid. Sections of fresh bone stained more slowly. When removed from the staining solution the sections were dried, and having been again carefully polished up, were examined in air or in Canada balsam. From examination of different bones and bones of different ages (young, adult, old), it was found that the staining was proportionate to the ^changes going on. Thus, in young bone the staining was more pronounced in the subperiosteal and subendosteal regions than in adult bones, and much more than in old osseous tissue. (5) Mounting1, including Slides, Preservative Fluids, &c. To rectify Turpentine for Microscopical Use.j — Mr. Charles C. Faris writes: — As it is difficult to obtain nice, clear turpentine for micro- scopical purposes, I want to give other workers the benefit of my expe- rience in rectifying the ordinary fluid. I proceed as follows : — Take one pint of the common turpentine and mix in a quart bottle with 4 oz. of 98 per cent, alcohol. Agitate well, and let stand until the two fluids separate. Decant the turpentine (which will form the lower layer) from the alcohol, and mix it with one pint of clear water. * Anat. Anzeig., x. (1890) pp. 325-36. f The Microscope, x. (1890) p. 179. L 2 148 SUMMARY OF CURRENT RESEARCHES RELATING TO Agitate thoroughly, and let stand until these two fluids separate, then from the water decant the turpentine (which this time will form the upper layer), and finally, mix with the turpentine about 1 oz. of pow- dered starch, and filter through paper. By pursuing the foregoing plan any one may secure a pure, limpid, and brilliant turpentine. The alcohol used in rectifying it need not be wasted, as it will do to bum, to clean slides, or for other purposes. I usually make a large quantity, and recover the alcohol by distillation. (6) Miscellaneous. Biological Examination of Potable Water.* — Mr. G. W. Rafter describes a modification of Prof. W. T. Sedgwick’s method of deter- mining the number of organisms in drinking water. The water is filtered through a short column of fine sand in the stem of a funnel, the sand being supported on a plug of wire-cloth placed beneath it. The sand retains the whole of the organisms contained in the water. After the completion of the filtration, the sand is washed with distilled water into a test-tube, and shaken, when all the sand falls to the bottom and the organisms remain uniformly distributed through the water. A definite quantity of this is taken out by a pipette and placed in a cell of known dimensions. The enumeration of the organisms is accomplished by transferring the cell to the stage of the Microscope and examining with the aid of the micrometer. Tests for Glucosides and Alkaloids.t — Herr A. Rosoll gives the following tests for berberin and cytisin : — Berberin dissolves in con- centrated nitric acid with a reddish-brown colour, and may then be precipitated in star-like groups of crystals of berberin nitrate by the successive action of alcohol and nitric acid ; or it can be precipitated as characteristic green capilliform crystals by potassium iod-iodide from the alcoholic solution ; the crystals being again soluble in sodium hyposulphate. It occurs in all the organs of mature plants of Berberis vulgaris. Cytisin occurs in all parts of the laburnum, but there are only traces in the leaves or flowers. It gives a red-brown precipitate with potassium iod-iodide, leaf-like groups of crystals with picric acid ; a light reddish-yellow solution with sulphuric acid, which becomes yellow, brown, and finally green, on addition of a small piece of potas- sium bichromate ; a yellow turbidity with phosphor-molybdic acid. Tests are also given for coniferin, phloroglucin, vanillin, salicin, syringin, hesperidin, solanin, saponin, tannin, veratrine, strychnine, brucine, colchicine, nicotine, aconitine, and atropine. The author asserts that strychnine occurs in solution in the drops of oil held in solution in the endosperm-cells, and not, as sometimes stated, in the thickenings of the cell-walls. Materials of the Microbe-Raiser.:}: — Dr. S. Hart makes the fol- lowing somewhat amusing remarks : — “ Some of the means and methods * Proc. Rochester (X.Y.) Acad. ScL, 1890, 10 pp. and 4 figs. t ‘ Ueb. d. mikrochemisclen Xachweis d. Glycoside u. Alkaloide,’ Stockerau, 1890, 25 pp. See Bot. Centralbl., xliv. (1890) p. 44. X -‘Invisible Assailants of Health,” ‘Popular Science Monthly.’ See Amer. Mon. Micr. Joum., xi. (1890) p. 232. ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 149 of the micrologist in his researches must he mentioned. His outfit is extensive and novel. It includes the best known Microscopes and a well-constructed incubator with heater and thermometer, numerous test-glasses, beakers, filters, acids, alkalies, deep-coloured dyes, and a good supply of prepared cotton. In studying the life-history of his microbes he will require a well- supplied commissariat. He must be a professional caterer and a boun- tiful feeder. He must have fluids, semi-fluids, and solids, broths of various meats, peptonized food, the serum of blood a la Koch , and Pasteur’s favourite recipe with the French refinement : Recipe, 100 parts distilled water, 10 parts pure cane-sugar, 1 part tartrate of ammonium, and the ash of 1 part of yeast. Among the substantial must be found boiled white of egg, starch, gelatin, Japan isinglass, and potato, the last from South as well as North America.” A Query. — As “ Novice ” will perhaps get the best advice by means of our Journal we hasten to give his questions the widest publicity we can : — “ I am thinking of starting a street exhibition with four Micro- scopes (two by Beck and two by Watson). Will some kind reader please tell me which objectives I should use to please the public most — 1/4, 1/2, 1, 2, or 3 in. ? Also please tell me of a few good mounted objects that will please them as well ; and which objectives I should use to get the best result when examining a frog’s foot. And do you think there is a living of, say, 35s. per week by going from town to town? Any information on the above will be gladly received by — Novice.” * Eng. Mech., lii. (1891) p. 471. ( 150 ) PROCEEDINGS OF THE SOCIETY. Meeting of 17th December, 1890, at 20, Hanover Square, W., Prof. Urban Pritchard, Vice-President, in the Chair. The Chairman having declared the meeting to he made special for consideration of matters adjourned from the adjourned special meeting held 19th November, the Secretary said that the Council were still unable to recommend any course of action on the matters under consideration, and therefore advised that the adjournment of the special meeting be sine die. It was moved by Mr. J. M. Allen, seconded by the Rev. Canon Carr, and resolved, “ That this special meeting be adjourned sine die .” The Minutes of the meeting of 19th November last were then read and confirmed, and were signed by the Chairman. 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. Six Slides of Leptodora hyalina Slide of Ceratium longicorne Three Lithographs of Fresh- water Sponge Two Photomicrographs of ditto From Mr. T. Clarke. Mr. J. Clark. Mr. T. Clarke’s letter relating to his donation of slides was read. Mr. Joseph Clark's description of his lithographs and pliotomicro- grajihs wTas read. Mr. G. F. Do wdes well’s note was read with reference to a small eye-piece thread-micrometer which he had sent to the meeting for exhibition, and which he stated was made about five years ago, and em- bodied the same principles as the one exhibited by Mr. Nelson at the meeting of the Society in May, and described in the August number of the Journal. A short further communication from Mr. Dowdeswell was also read in reply to some observations and inquiries with reference to the “ simple form of warm stage,” exhibited and described at the meeting of the Society in October last. Mr. J. Mayall, jun., said he thought that the means by which it was proposed to keep this stage warm — i. e. by applying a small flame below the projecting corner of it — were not sufficiently precise to render it possible to keep the temperature within a variation of one degree, as suggested by Mr. Dowdeswell. According to the opinion of Dr. Dallinger it was of the utmost importance, that in all observations bearing upon the influence of temperature on the forms of life and development, the means of regulating and maintaining the temperature of the stage should be absolutely under control, and he feared this could hardly obtain with the method described by Mr. Dowdeswell. Mr. E. M. Nelson having examined the micrometric eye-piece, said it appeared to him to be a *• Jackson eye-piece micrometer,” and that was PROCEEDINGS OF THE SOCIETY. 151 all. It Lad no movable throad so far as he could see ; the scale moved sometimes, but not the web. Mr. Mayall said the apparatus was so shaky that ho supposed it had met with an accident. The general construction reminded him of the designs of the Continental screw-micrometers, and also of the screw mechanism frequently employed on the Continent for stage movements, centering, &c., in most of which unnecessarily long and thin screws were applied, which were very liable to be bent, and to become loose in their sockets. He thought the defective condition of Mr. Dowdeswell’s micrometer should serve as a warning to opticians generally of the error of making screw-axes too long and thin, especially those having milled heads, and, consequently, intended to be moved by hand. In all the high-class screw-micrometers and similar mechanism, the actuating screws and their bearings were made large and substantial, with a view to securing accuracy of movement, durability, and freedom from flexure. He might mention particularly that in examining a large number of Microscopes by different makers, he had observed that the centering screws of the mechanical substages were generally too slight, and were provided with such short sockets that they were very liable to become shaky. These were points of importance in the construction of Microscopes and accessory apparatus. Mr. Mayall said he had prepared a short note for publication in the Journal (see ante, p. 107) upon a matter in connection with photo- micrography, which he thought the Fellows of the Society would agree with him called for some protest — the practice of sending photographs there as specimens and illustrations without at the same time stating the details of the process by which they were produced. On submitting the note to Prof. Bell, it had been thought advisable to deal with it as a communication to the Society, in the hope that it might lead to useful discussion. Before inviting discussion, he said his attention had been specially drawn to the subject by the fact that at one of their recent meetings a photograph of P. angulatum , by Dr. Yan Heurck, had been exhibited, and had elicited from Mr. Frank Crisp the observation that it was § £ S ® o “ |3 s — c I 2 1& II <-J;g 1 I » | L§ ^ 'c s | I $-1 l1||i Is ■sf^ja sapfiS— ’ 3 £ SP c .s Z = _ g.-S'S-.Sg >> 3? * I § II ^ C R O ^ ^ C C O CCNr-r.OO 0X0 'll 3 II -s § 'll £ o <3 o . ' OJ ~ s II * Z^J - z = ? 0 2-f“i - 5 -cg^-3 = *.^ IHililll £ srrsstss 1 2‘ The forogoing Annual Account examined and found correct, 5th January, 1891. J. I). Hardy, \ W. T. Suffolk, / Au< PROCEEDINGS OF THE SOCIETY. 159 The Scrutineers having handed in the result of their examination of the balloting papers, The President declared that all the Fellows nominated were elected as follows : — President — *Robert Braithwaite, Esq., M.D., M.R.C.S., F.L.S. Vice-Presidents — *Prof. J. William Groves, F.L.S. ; * Albert D. Michael, Esq., F.L.S.; *Prof. Charles Stewart, Pres. L.S. ; Charles Tyler, Esq., F.L.S. Treasurer — Frank Crisp, Esq., LL.B., B.A., Y.P. and Treas. L.S. Secretaries — Prof. F. Jeffrey Bell, M.A. ; and John Mayall, Esq., Jun., F.Z.S. Twelve other Members of Council — *Prof. Lionel S. Beale, M.B., F.R.C.P., F.R.S. ; Alfred W. Bennett, Esq., M.A., B.Sc., F.L.S. ; Rev. W. H. Dal linger, LL.D., F.R.S. ; * James Glaisher, Esq., F.R.S., F.R.A.S. ; Richard G. Hebb, Esq., M.A., M.D. ; ^Charles T. Hudson, Esq., M.A., LL.D. (Cantab.), F.R.S. ; George C. Karop, Esq., M.R.C.S. ; Thomas H. Powell, Esq. ; *Prof. Urban Pritchard, M.D. ; Walter W. Reeves, Esq. ; William Thomas Suffolk, Esq. ; and Frederic H. Ward, Esq., M.R.C.S. Mr. G. C. Karop then moved that the thanks of the Society be given to the Auditors and Scrutineers for their services, and the motion having been seconded by Mr. F. Justen, was put to the meeting by the President, and carried unanimously. The President said he had now the pleasure of welcoming to the Chair his well-known and learned successor Dr. Braithwaite, and of congratulating the Society, not only on so happy a choice, but also on the fact that the Zoological Dynasty had made way for a Botanical one. Variety was the salt of life, and it was a fortunate thing that their large and flourishing Society contained members who, though of very various tastes, resembled one another in their zealous pursuit of natural science, and in the success with which they pursued it. With the wish that Dr. Braithwaite might have a long, happy, and prosperous reign, he became now one of the most loyal of his subjects. Dr. Braithwaite, who was very cordially received on taking the Chair, said he had in the first instance to thank the retiring President for the kind way in which he had referred to him, and next to thank the Fellows of the Society for the honour conferred upon him by his election to the position he was about to occupy. Ho could assure them that, so far as he was able to sustain it, the high position which the Society then held should not suffer from the change which they had made. He knew that the position was not a light one, but he was encouraged by the sight of many old friends before him to believe that those who so ably assisted him in the discharge of similar duties at another Society some years ago, would also give him the benefit of their assistance during the coming year. One observa- tion, however, he should very much like to make before he sat down ; he thought it very desirable that original papers should fill a much * Have not held during the preceding year the Office for which they were nomi- nated. 160 PROCEEDINGS OF THE SOCIETY. larger space in the Journal than was at present the case. The Journal had already a world- wide reputation, and the surest way to maintain this would be to increase as far as possible the number and value of their original communications to the Society. The following Instruments, Objects, &c., were exhibited. Mr. E. M. Nelson : — Powell and Lealand’s new Apochromatic Con- denser. Mr. J. Swift : — Improved form of Dick’s Polarizing Microscope. New Fellows: — The following were elected Ordinary Fellows: — Messrs. Alfred L. Blow, F.C.S., and Arthur D. Howard. The Journal is issued on the third Wednesday of February, April, June, August, October, and December. £ H 1891. Part 2. APRIL. /To Non-Fellows \ Price 5s. Wtq ‘l Journal OF THE Royal Microscopical Society CONTAINING ITS TRANSACTIONS AND PROCEEDINGS, AND A SUMMARY OF CURRENT RESEARCHES RELATING TO ZOOX,OO^r jP^IsTJD botany (principally Invertebrata and Cryptogamia), MICROSCOPY,