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QUARTERLY JOURNAL 


MICROSCOPICAL SCIENCE. 


EDITED BY 


EDWIN LANKESTER, M.D., F.RB.S., F.L.S., 


GEORGE BUSK, F.R.C.S.E., F.R.S., F.L.S. 


VOLUME IL 


GHith Allustrations on Wood and Stone. 
On, A 


. LONDON: 
SAMUEL HIGHLEY, 32, FLEET STREET. 
1854, 


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INDEX TO JOURNAL. 


VOLUME II. 


A. 


Actinophenia, Shadbolt, G., on, 201. 

Allman, Prof., on the structure, &c., 
of Bursaria, 61. 

on the probable 
structure of the starch granule, 
163. 
on the cellular struc- 
ture of Hydra viridis, 61. 

Amylacea corpora, Virchow, on, 101. 

Anacharis alsinastrum, F. Branson, 
M.D., on, 131. 

on the rotation 
of the cell-sap in, G. Lawson, on, 
132. 
a on the rotation 
in the cells of, 54. 

Angular aperture of the object-glasses 
of compound microscopes, on the 
relation of to their penetrating 
power to oblique ra ee by J. W. 
Griffith, M.D., 294 

Animalcules, on the colouring of, 
observations on, by T. C. White, 
282. 

Aperture, angle of, W. S. Gillett, on 
the, 293. 

oe of object-glasses, F. H. 
Wenham, on the, 209. 

a of object-glasses, on the 
measuring of, and remarks on their 
adjustment, F. H. Wenham, on the, 
134. 


Aquarium, the, by P. H. Gosse, 
notice of, 278. 

Arthromitus, 193. 

Arthrodesmus incus, 237. 

Arthroderma, 242. 

Asplenium  septentrionale, spermato- 
zoids of, 126. 

Asteraspori tum (Hoffmanni 2), 120. 


VOL. Il. 


| 
| 


B. 


Bailey, Prof. J. W., List of the Dia- 
tomacee procured in the United 
States Exploring Expedition, 288. 

Barry, Dr. M., on the structure of 
the muscular fibrill and the mus- 
cularity of cilia, 116. 

Bary, Dr. Anton de, De generatione 
sexuali plantoruum, 44. 

Baum der, studies on the structure 
and life of the higher plants, by 
Dr. H. Schacht, 128. 

Beale, Dr, Lionel, on cysts in the 
kidney, 196. 

me the microscope and its 
application to clinical medicine, 
267. 

on a method of apply- 
ing chemical re-agents to minute 
quantities of matter, 58. 

Binocular microscope, on a, by M. 
Nachet, 72. 

7 magnifier, 19. 
microscope, 
Riddell, on the, 18. 
i microscope, F. H. Wenham, 
on the, 132. 
in and stereoscopic micro- 
scope, W. Hodgson, on a, 57. 

Bituminite, Prof. Traill, on, 143. 

‘Black fur’ on the tongue, Dr. En- 
lenberg. on a, 263. 

Blut im Brode, 121. 


Proi e . 


- Boghead coal, composition of, by J. 


Normandy, 200. 
“Fs Prof. W. Gregory, ov, 

201. 

Bone, Dr. Redfern, on the structure 
of, 61. 

Botanieal letters, by Dr. F. Unger, 
review of, 123 

Y 


298 


Boswell, R. S., on Cellularia plumosa, 
205. : 

Branson, Dr. F., on Anacharis alsi- 
nastrum, 131. 

Braun, Dr. A., on some new or little- 
known discovery of plants caused 
by Fungi, 250. f 

” on Rejuvenescence 1 
Nature, 279. 

Bristowe, Dr., on the occurrence of 
hematoid crystals in a hydatid 
eyst, 195. 

Bursaria, Prof. Allman, on the struc- 
ture, &c. of, 61. 

Busk, G., on a developing solution 
for microphotographs, 203. 


x description of a magnetic 
stop to the microscope, 280. 
= on the occurrence of appa- 


rent starch granules in the brain, 
105. 

5 catalogue of the marine 
Polyzoa in the collection of the 
British Museum, 277. 


C, 


Camera lucida, on the use of as a 
micrometer, 291. 

Cells, ciliated, R. Virchow, on the 
irritability of, 108. 

Cellularia plumosa, R. 8, Boswell, on, 
205, > 

Cellulose, on a substance presenting 
the chemical reaction of, found in 
the brain and spinal chord of man, 
by R. Virchow, 101. 

Cementing pencil, brass, description 
of, by J. Gorham, 56. 

Chara, on the multiplication of by 
division, 40. 

Chromatophores in the frog, R. 
Virchow, on, 254, 

Cladophytum, 193. 

Clostertum Leibleinii, 236. 

a limula, on cilia in, by §8. 

G. Osborne, 234. d 

Coal ; is it a mineralogical species? 
140. . 

Coles, Henry, on the camera lucida 
as a micrometer, 291. 

Collomia coccinea, hairs of, 43. 

Colouring of animalcules, on the, 282. 

Condenser, Powell and Lealand’s, 
Dr. Inman, on, 60. 

Connectivegtissue, on the develop- 
ment of, Prof. A. Kolliker, 178. 

Contractile substance of the lowest 
animals, A. Ecker, on the, 1) 1. 

Corpuscula tacttis, note to Mr, Hux- 
ley’s paper on the, 139. 


INDEX TO JOURNAL. 


Corpuscula tactis, and Pacinian bo- 
dies, structure and relations of, 1. 

Corynocladus, 193. 

Criiger, H., on the development of 
starch, 173. 

Crystals, hematoidin in a hydatid 
cyst, Dr. Bristowe, on, 195. 

Currey, F. M. A., on two new fungi, 
240. 

es translation of Schacht on 
the microscope, review of, 45. 

Cutaneous diseases, caused by para- 
sitic growths, by Dr. B. Gudden, 
on, 185. 

6 dependent on pa- 
rasitic growths, Dr. B. Gudden, on, 
29. ; 

Cuticle of ligneous plants, on the, 43. 

Cysts in the kidney, Dr. L. Beale, on, 
196. 

Cysticercus pisiformis, on the trans- 
formation of into Vania serrata, 
255. 

D. 


Desmidium quadrangulum, 240, 

Developing solution for microphoto- 
graphs made by artificial light, 205. 

Diatomaceous deposit of Mull, Prof. 
Gregory, on the, 24. 

Diatomacez found in the vicinity of 
Hull, Sollitt, J. D., and Harrison, 
R., on the, 61. 

ss as test objects, 61. 

Es list of the, discovered 
in the United States Exploring 
Expedition, 288. 

Diatomaceous earth of Mull, on the, 
with remarks on the classification 
of the Diatomacez, by Prof. Gre- 
gory, 90. 

Didymoprium Borreri, 240. 

Diseases of plants caused by Fungi, 
Dr. A. Braun, on, 250. 

Docidium, 237, 240. 

Doryphora? elegans, 284. 


E. 


Eccrina, 193. 

Ecker, Prof. A., on the ‘ contractile 
substance of the lowest animals,’ 
Lads 

Elastic fibres, on the development of, 
by Prof. A. Kolliker. 178. 

Enchondroma of the Testis, Jabez 
Hodgson, on, 195. 

Enterobryus, 192. 

Equisetum arvense, spermatozoids of, 
126. 

Kulenberg, Dr., on a ‘ Black Fur’ on 
the tongue, 263. 


INDEX TO JOURNAL. 


F. 


Filaria, on a species of, found in the 
blood of the dog, 33. 

Fischer, Dr. L., on the Nostachacee, 
43. 

Flora and Fauna within living ani- 
mals, by Dr. J. Leidy, review of, 
190, 

Fly’s foot, on the structure of, John 
Hepworth, 158. 


Fresenius, Dr. G., contributions to | 


mycology, by, 118. 
Frog, on chromatophores in the, 254. 
Fungi, on two new, F. Currey, M.A., 
240. 
a. OM aeuaen of plants, caused 
by, 250. 
Fungoid growth in the nails, Meiss- 
ner, C., on a, 38. 


G. 


Generatione sexuali planterum de, 
Diss, 44. 

Gillet, W. S., on the angular aperture 
of object glasses, 293. 

Gorham, J., on a ‘brass cementing 
aaa - 56. 

ona ‘holder,’ for mount- 
ing objects i in the dry way, 56. 
i on the magnifying power 
of short spaces, &c., 218. 

Gosse, P. H., Naturalists Rainbles on 
the Devonshire Coast, review of, 
47. 

6 The Aquarium,&c., 278. 

Gregory, Prof. W., on the diatoma- 
ceous deposit of Mull, 24. 

Griffith, J. W., M.D., on the angular 
aperture of object glasses, &c., 294. 

Gruby, M. M., on a species of Filaria 
found in the blood of the dog, 33. 

Gudden, Dr. B., on cutaneous diseases 
dependent upon parasitic growths, 
29. 

Be on diseases caused by 
parasitic growths, 185, 


H. 


Hartig, on the cuticle of. ligneous 
plants, 43. 

Hepworth, John, on the structure of 
the fly’s foot, 158. 

Herapath, W. B., on the manufacture 
of large available erystals of iodo- 
quinine (Herapathite), 83. 

on quinine and 
quinidine (8 quinine) in the urine, 
13.. 


299 


| Highley, S, on coal, is it a mineralo- 


| 
| 


gical species, 141. 

Hodgson, W., on a binocular and 
stereoscopic microscope, 57. 

Hoffman, Prof. H., on contractile 
tissues in the Hymenomycetes, 243. 

Hogg, Jabez, the microscope, &c., 
277. 

‘3 on Enchondroma of the 
testis, 195. 

Holder, for mounting objects in the 
dry way, Gorham, J., on a, 56. 

Hunt, G., on the spiral vessel of 
rhubarb 288. 

5 on the rotation in Vallis- 
neria spiralis, 55. 

Huxley, T. H., on the structure and 
relations of the Malpighian bodies 
of the spleen and tonsils, 74. 

on the structure and 
relations of the A tactis 
and Pacinian bodies, 1. 

Hydra viridis, Prof. Allman, on the 
cellular structure of, 61. 

Hymenomycetes, on contractile tissues 
in the, Prof. H. Hoffmann, 243. 

Hyphomycetes, on the flocci of, 119. 


iF 


Illumination of objects under the 
microscope, with relation to the 
aperture of the object-glass, &c., 
F. H. Wenham, on the, 145. 

3 of transparent objects, 
G. Rainey, on, 7, 65, 285. 

Infusionsthiere die, ae by Dr. F 
Stein, notice of, 272. 

Inman, Dr. T., on Powell and Lea- 
land’s condenser, 60. 

Iodo-quinine (Herapathite), on the 
manufacture of large available erys- 
tals of, 85. 

Itzigsohn, Dr. H., on the existence of 
spermatazoids in certain freshwater 
alge, 35. 

on the propagation 
of the Oscillarie, 188. 


J. 


Jones, Dr. Handfield, on mamellation 
of the gastric mucous membrane, 
195. 

on a peculiar 
form of uric acid crystals, 196. 


K. 


Kolliker, Prof. A., on the develop- 
ment of nuclear fibres, elastic fibres, 


and of connective tissue, 178. 


300 


Ie 


Lawson, G., on the rotation of the 
cell-sap in Anacharis alsinastrum, 
132. 


on the rotation in the 


cells of plants, 54. 

Leidy, Dr. Joseph, Flora and Fauna 
within living animals, 192. 

Leptothrix, 189. 

Leydig’s Anatomico-histological, ob- 
servations on fishes and reptiles, 
review of, 126. 

» onthe muscular structure in 
Paludina vivipara, 36. 

Ligneous plants, on the cuticle of, 43. 

London Medical Society, physiologi- 
eal section of, 142. 

Lungs, Sarcina in the, 41. 


M. - 

Magnetic stage to the microscope, 
description of a, 280. 

Magnifying power of short spaces, 
illustrated by the transmission of 
light through minute apertures, 
John Gorham, on the, 218. 

Malpighian bodies of the spleen and 
tonsillar follicles, T. H. Huxley, 
on the ultimate structure and rela- 
tions of 74, 

Mamellation of the gastrie mucous 
membrane, Dr. H. Jones, on, 195. 
Manglesia cuneata, development of 

the flower and fruit of, 43. 

Meissner, C., on a fungoid growth in 
the nails, 38. 

Memoirs, botanical and physiologi- 
eal, published by the Ray Society, 
279. 

Micrographie dictionary, the, notice 
of, 278. 

Micrometer, for the microscope, on 
the best form of, 51. 
‘i on the use of the Camera 
lucida as a, 291. 
with microscope, G. 
Jackson, on the best forms of, 129. 

Microscope, the, its history, con- 
struction, and application, by Jabez 
Hogg, review of, 277. 

es the, and its application 
to clinical medicine, by Dr. L. 
Beale, review of, 267. 

5 adapted for anatomical 
demonstrations, and on a binocular 
microscope, by M. Nachet, 72. 


oS the, in its special appli- | 


cation to vegetable anatomy and 
physiology, by Dr. H. Schacht, 45. 


INDEX TO JOURNAL. 


Microscopical Society, 
of, 142, 205, 293. 

Moderator light, Rainey’s, 141. 

Montagne, M. C., on the multiplica- 
tion of Chara by division, 40. 

Monas prodigiosa, 121. 

Muciparous canals of fishes, 6 

Muscular structure in Paludina vi- 
vipara, Leydig, on the, 36. 

i fibril, on the structure of, 
and the muscularity of cilia, by 
Dr. M. Barry, 116. 

peters y, contributions to, by Dr. G. 

F. Fresenius, 118. 


proceedings 


N. 


Nachet, M., de Paris, on a microscope 


adapted for anatomical demonstra- 
tions, and on a binocular micro- 
scope, 72. 

Naturalist’s Rambles on the Devon- 
shire Coast, review of, 47. 

Nature, Prof. A, Braun’s Treatise of 
Rejuvenescence in, 279. 

Normandy, J., on the composition of 
Boghead coal, 200. 

Nostochacez, an attempt at the natu- 
ral arrangement of, &c., 43. 

Nuclear fibres, the development of, 
Prof. A. Kolliker, 178. 


O. 


Oiduim Tuckeri, 44. 

Okeden, Fitzmaurice (C.I.), on two 
species of Triceratium, 284. 

Ophiotheca, 241. 
Osborne, The Hon. §. G., on ciliary 
motion in Closterium limula, 234. 
Oscillarie, on the propagation of, 
Dr. H. Itzigsohn, 188. 

Oscillaria tenuis, 189. 

Oudemans, Dr., on the hairs of Col- 
lomia coccinea, 43. 


BP. 


Pacinian bodies, structure and rela- 
tions of, 1. 

Pacini, Prof., on the structure of the 
retina, 199. 

Paget, James, Lectures on surgical 
pathology, 197. 

Paludina vivipara, note on the mus- 
cular structure of, 36. 

Parasitic Fungi, mode of growth of, 
Edward Tucker, on, 204. 

Pathological Society, transactions of, 
review of, 195. 

Paul, Dr. B, translation of Unger’s 
botanical letters, 123. 


INDEX TO JOURNAL. 


Pentium, 237. 

Peziza macrocalyzx, 121. 

Phormidum, 189. ; 

Photographs match, or camera lucidu 
drawings of microscopic objects for 
the stereoscope, Prof. Riddell, 290. 

Pinnularia hebridensis, 27. 

Pityriasis versicolor, 185. ‘ 

Polyzoa, marine, in the collection of 
the British Museum, catalogue of, 
277. 

Powell and Lealand’s condenser, Dr. 
Inman, on, 60. ’ 

Pseudo-entophyta, Dr. J. Leidy, on, 
194. 


Q. 


Quinine and quinidine (8 quinine) 
in the urine, 13. 


R. 


Rainey’s light moderator, 141. 

Rainey, G., on the illumination of 
transparent objects, 7, 65, 285. 

Ray Society, botanical and physio- 
logical memoirs, published by, 279. 

Reagents, chemical, on a method of 
applying to minute quantities of 
matter, by L. Beale, 58. 

Retina, on the structure of, 199. 

Rhubarb, on the spiral vessel of, 288. 

Riddell, Prof. J. L., on the binocular 
microscope, 18. 

» on match photographs, 
&e., 290. 

Robinson, The Rev. T. R., on the 
measuring of the angular aperture 
of the objectives of microscopes, 
295. 

Roper, F. C. S., on three new British 
species of Diatomacez, 283. 

Rotation in the cells of plants, G. 
Lawson, on, 54. 

“ in Vallisneria spiralis, G. 
Hunt, on the, 55. 

Royal Institution, on the construction 
of the compound achromatic mi- 
croscope, lecture on, by Charles 
Brooke, M.A., F.R.S., 205. 

Royal Irish Academy, on a new 
method of measuring the angular 
aperture of the objectives of micro- 
scopes, by the Rev. T. R. Robinson, 
D.D., 295. 

Royal Society, on a new and more 
correct method of determining the 
angle of aperture of microscopic 
object glasses, by W.S. Gillett, 293. 


301 


Royal Society of Edinburgh, proceed- 
ings of, 143. 


Ss. 


Sarcina in the lungs, 41. 

Savian bodies, 6. 

Schacht, on the microscope, review of, 
45, 

a rs “Der Baum 12s. 

Shadbolt, G., on the proposed new 
genus ‘ Actinophenia,’ 201. 

Siebold, C. Th. v., on the transforma- 
tion of Cysticercus pisiformis into 
Tenia serrata, 255. 

Sollitt, J. D., and Harrison, R., on the 
Diatomacee found in the vicinity of 
Hull, 61. 

Spermatozoids, on the existence of, in 
certain freshwater Alge, 35. 

Spiral vessel of rhubarb, on the, 288. 

Spleen, T. H. Huxley, on the struc- 
ture and relations of the Malpig- 
hian follicles of, 74. 

Starch, H. Criiger, on the develop- 
ment of, 173. 

», granule, Prof. Allman, on the 
probable structure of, 163. 

x Busk, on the occurrence of 
particles resembling starch in the 
brain, 105. 

Stein, Dr. F., die Infusionsthiere, auf 
ihne Entwickelungs Geschichte un- 
tersucht, 272. 

Stereoscopic and binocular micro- 
scope, W. Hodgson, on a, 57. 

Stirrup’s microscope, 140. 

Surgical pathology, lectures on, by 
Jas. Paget, review of, 197. 

Symploca, 189. 


40 


Tenia serrata, derived from the trans- 


formation of Cysticercus pisiformis, 
255. 

Test objects, Diatomacee as, 61. 

Tongue, ‘ Black Fur’ on the, 263. 

Tonsils, T. H. Huxley, on the strue- 
ture and relations of the Malpighian 
bodies of, 74. 

Torbane Hill miueral, Prof. Traill, on 
the, 143. 

Tourmalines, artificial, on the manu- 
facture of, 83. 

Traill, Prof., on the Torbane Hill 
mineral, 143. 

Transparent objects, on the illumina- 
tion of, 7, 65. 

Triceratium armatum, 283. 

Tucker, Edward, on the mode of 
growth of parasitic Fungi, 204, 


302 INDEX TO JOURNAL. 


Tulasne, L, B., on the germination of | Virchow, R., on cellulose in the brain 


the spores of the Uredinez, 110. and spinal chord of man, 101. 
U. | W. 
Uvella, 190. 
Unger, Dr. F., botanical letters of, | Wenham, F. H., on the binocular mi- 
123. croscope, 132. 
Uric acid crystals, peculiar form of, on the aperture of 
described by Dr. H. Jones, 196. object "glasses, &c., 134. 
Uredinee Tulasne, on the germina- on the aperture of 
tion of the-spores of, 110. object ‘elasses, 209. 
on the illumination 
Vv of - objects under the microscope, 
a &e., 145. 
Vibrisse, analogy of, with the muci- White, T. C., on the colouring of 
parous glands of fishes, 6. animalcules, 282. 
Vine, diseases of, 44. 
Virchow, R., on chromatophores in DEA 
the frog, 254. 
on the irritability of | Xanthidium armatum, 287. 


ciliated cells, 108. | Zoogalactusa tmetropha, 121. 


. 


Lonpon : Printed by W. Cowes and Sons, Stamford Street and Charing Cross, 


QUARTERLY JOURNAL 


OF 


MICROSCOPICAL SCIENCE, 


ORIGINAL COMMUNICATIONS. 


On the SrructurE and Rewation of the Corpuscuta Tactus 
( Tactile Corpuscles or Axile Corpuscles), and of the Pactnian 
Bopvies. By Tuomas H. Huxtey, F.RS. 


In February, 1852, Professor Wagner published in the Got- 
tingen ‘ Gelehrte Nachrichten,’ the results of some observa- 
tions, made by G. Meissner and himself, the tendency of 
which was to establish the existence of peculiar bodies in 
certain of the papille of the fingers and palm of the hand, to 
which, from their relation to the nerves entering the papilla, 
he ascribed special functions, and thence proposed to confer 
upon them the name of corpuscula tactus—Tactile corpuscles. 
Wagner’s principal positions are the following :— 

1. The papilla of the hand are of two kinds—nervous and 
vascular—the vascular papille containing no nerves, and the 
nervous papille possessing no vessels. 

2. The nervous papille contain a peculiarly constructed 
oval mass, like a fir-cone, composed of bands or rows, arranged 
one behind the other. 

3. The dark-bordered nerve-fibres enter the papilla, pass 
to this ‘‘ tactile corpuscle,” and terminate in it, either free or 
dividing into five branches. 

4, These corpuscles are analogous to the Pacinian bodies. 

5. They are specially subservient to sensation. 

Professor Kélliker, whom this Memoir touched somewhat 
directly, replied in the ‘ Zeitschrift fiir Wissenschaftliche 
Zoologie’ of the following June, by an essay on the same 
subject (Ueber den Bau der Cutispapillen und der soge- 
nannten Tactk6rperche R. Wagner’s), in which, having care- 
fully repeated and extended Wagner’s observations, his 
general conclusions are :— 

1. a. The corpusculated papilla often contain vessels. 

6. The vascular papilla of the lip contain nerves. 

VOL. ITI. B 


2 ON THE CORPUSCULA TACTUS. 


c. In the lip and hand there are a few papilla without 
axile corpuscles and with nerves. 

2. The tactile corpuscle is not a peculiar body, but the 
ordinary embryonic connective tissue remaining as the axis 
of the papilla. Kdlliker therefore proposes to call it “axile 
corpuscle.” 

3. The nerves do not enter and terminate in the corpuscle 
but wind round it and form loops. 

4. The cdrpuscles are not specially subservient to sen- 
sation. 

Besides the surface of the hand Kolliker found these 
corpuscles only in the red edges of the lips and at the point of 
the tongue. : 

Finally, in Miiller’s Archiv for 1852, Wagner, in a com- 
munication accompanied by very good figures (Ueber der 
Tactkorperchen, Corpuscula Tactus, Mull. Arch. H. 4), re- 
ferring to the discrepancies between Kolliker and himself, 
considers the question as to the peculiarity of the structure of 
the corpuscles to be still open; he denies that the nerve 
fibres form loops on the axile corpuscles (quoting, in confir- 
mation of his own views, Meissner, Ecker, Briiche, and Giins- 
burg), and, also, that nerves enter any papillae but those pro- 
vided with tactile corpuscles. Wagner admits, however, that 
certain of the papillz containing axile corpuscles also exhibit 
vascular loops, but these, according to him, always have nervous 
tissue at their extremities, and are in fact formed by the coales- 
cence of a nervous and vascular papilla. Without pretending 
to decide, when two such eminent doctors in physiology dis- 
agree, I beg to lay before the reader the following results of 
my own examination of this matter, accompanied by some 
figures drawn ona larger scale, and with more attention to 
detail than those furnished by Wagner or Kolliker. I can 
best arrange what I have to say in the order of the points in 
dispute, as given above. 

1. In the human finger I have met with corpusculated 
papilla containing vascular loops, though rarely (PI. I. fig. 2) ; 
but I have observed no papillae without corpuscles, to present 
nerves. That there is not, however, necessarily an inverse 
relation between the presence of vessels and that of nerves, 
is shown by the fungiform papille of the sides of the base of 
the tongue in the Frog, in which very evident dark-contoured 
nerves may be seen terminating in papilla, without any trace 
of a_ tactile corpuscle, and with a large vascular loop 
(fig. 6). 

2. Everything I have seen leads me to believe with 
Kolliker, that the ‘corpuscle’ is not histologically, in any re- 


ON THE CORPUSCULA TACTUS. 3 


spect, a special structure, but merely rudimentary connective 
tissue (areolated embryonic connective tissue of Kolliker), 
exactly resembling that which is to be found in the rest of 
the papilla. This consists in fact of a homogeneous matrix 
in which endoplasts (nuclei) are embedded, and which, in 
various directions surrounding and radiating from these, is 
metamorphosed into a substance more or less resembling 
elastic fibre. The sole difference from the surrounding sub- 
stance presented by the corpuscle consists in this, that these 
elastic bands and filaments are more or less parallel to one 
another, and perpendicular to the axis of the corpuscle 
(fig. 1). : 
In one respect, however, [ believe that the corpuscles are 
peculiar, and something more than the mere, imperfectly 
formed axis of the papilla. Kolliker has pointed out (le. 
p- 67) that the nerve-tubules which enter the papilla are 
accompanied by a delicate neurilemma, and I believe that the 
“corpuscles” are its continuation and termination. In structure, 
the neurilemma which surrounds the more delicate branches 
of the nerves in the human finger (fig. 7) is identical with the 
** corpuscles,” except that in the former the elastic element is 
disposed parallel with the nerve fibre, while in the latter it 
is more or less perpendicular to it. In fact, I believe, that 
the “corpuscle” is simply the modified extremity of the 
neurilemma of the nervous tubules which enter the papille. 
3. With respect to the extremely difficult question of the 
mode of termination of the nerves, | may state that, without 
having any reason to urge against the existence of loops (on 
the contrary, having observed them very distinctly in the 
cutaneous papille of fishes), I have never been able to con- 
vince myself of their presence, and frequently when I believed 
I had such cases before my eyes, the use of a higher power, 
or the causing the papilla to turn a little, would undeceive me. 
On the other hand, it is by no means diflicult to obtain the 
clearest possible eridence of the occurrence of the so-called 
free ends (figs. 38, 4, 5). The dark-contoured fibres pass, 
sometimes only a little beyond the proximal extremity of the 
corpuscle (figs. 4, 5), sometimes quite to its distal end (fig. 3, 
and here fertiiinate by one or two pointed extremities, which 
appear to be continuous with the tissue of the corpuscle. I 
have never been able to obtain any evidence of the entrance 
of a dark-contoured nerve fibre into a “corpuscle.’ My 
belief that the nerves in the cor pusculated papilla of Man do 
really terminate in this manner, is strengthened by the ease 
with which this mode of termination may be demonstrated in 


the papille of the tongue of the Frog, to which reference 
B 2 


4 ON THE CORPUSCULA TACTUS. 


has been made above (fig. 6). Here four or five coarse 
nerve-fibres enter the papilla, run to its very extremity, 
become pointed, abruptly lose their fatty nature, and termi- 
nate in the delicate reticulated fibres, which represent the 
elastic element of the connective tissue of the part.* 

4. Wagner, as we have seen, compares the corpuscles to the 
Pacinian bodies, and I think with great justice. The Pacinian 
bodies are, as is well known, principally found attached to the 
nerves of the hand and foot in Man, to those of the mesentery 
in the cat, to the nerves of the extremities of many animals, 
to those of the skin and beak in birds, and to the intercostal 
nerves of the Boa constrictor. They are commonly said to be 
composed of numerous corpuscles of connective tissue, arranged 
concentrically, and separated by a clear fluid. The inner- 
most contains, besides this fluid, a nervous fibre, which 
terminates in a free clavate or branched extremity. 

In the human hand, however, I have invariably found that 
this description of their structure is not exactly correct. In fact, 
I find no interspaces filled with fluid, nor any central cavity. 
If the body be cut in two, each half remains as hard and uncol- 
lapsed as before; if it be torn, each layer of the ‘ corpuscle ” 
is seen to be united to its neighbour by a delicate, transparent, 
more or less granular, or sometimes fibrillated substance. 
Again, the nerve lies not ina cavity, but ina solid homogeneous 
substance ;.and, so far as I have seen, terminates more or less 
gradually in a portion of this mass, in which great numbers of 
endoplasts (nuclei) lie, and which has thence almost the ap- 
pearance of cartilage.{ The structure of the rest of the body 


* Much has been said as to the possibility of confounding capillaries 
with nerves; but I conceive that such a mistake could hardly be made by 
any careful observer, unless perhaps strong alkaline solutions had been 
allowed to act unwatched upon the preparation. I have made use of both 
acetic acid and caustic soda, and I find the latter more available in dis- 
covering nerves, the former in making out vessels and the general structure 
of the papilla ; inasmuch as it renders their ‘‘nuclei” more obvious, while 
soda makes them lessso. It is very useful sometimes to use these re-agents 
alternately ; and it is a good rule to apply them to the object only while 
under the microscope, so as to watch their gradual operation. 

+ According to Will (Reichert’s Report, p. 69, Mill, Arch. 1851), the 
contents of the central capsule of the Pacinian body in Birds is formed by 
a dense cellular mass, and closely applied cells exist in the external neu- 
rilemma. From observations upon these bodies in the Pigeon and Duck I 
can confirm this statement: in fact, the Pacinian bodies of the birds are 
very like the young forms of those of Man. I have also noticed, as Wagner 
states (1. c. p. 499), that the internal cellular mass is occasionally trans- 
versely striated, somewhat like a tactile corpuscle. The Pacinian bodies in 
Birds are much more superficial than in Man, being situated in the super- 
ficial layer of the corium, close to the sacs of the feathers. In the Pigeon 
they are very small, frequently not more than 1-150th—1-200th of an inch 


ON THE CORPUSCULA TACTUS. 5 


is, essentially, the same,* and the appearance of their concentric 
capsules is produced by the arrangement of their endoplasts 
in concentric layers in the outer part of the Pacinian body, 
and their connexion by the lamine and fibres of more or less 
imperfect elastic substance. 

The concentric lines in the Pacinian bodies are no more 
evidence that they are composed of capsules, than the parallel 
lines in the neurilemma of smal] nervous twigs (fig. 7) are 
evidence that it is composed of concentric tubes. In each 
case the appearances depend simply upon the disposition of 
the lines of elastic tissue. In fact, the Pacinian bodies are 
nothing more than thickened processes of the neurilemma of 
the nerve to which they are attached ; and differ from the “ tac- 
tile corpuscles” only in the circumstance that the thickening 
takes place on each side of the nerve fibril, while in the 
Pacinian body it takes place on both sides. The difference 
in the direction of the apparent layers is not so great as it 
seems, since, at each extremity of the Pacinian body, these 
are, as in the tactile corpuscle, perpendicular to the direction 
of the nerve. 

5. The evidence with respect to the physiological functions 
of either the corpuscula tactus or of the Pacinian bodies is 
wholly negative ; and it seems useless to enter upon the region 
of hypothetical suppositions. But I think that Comparative 
Anatomy promises to offer some assistance in this case by 
showing that these structures form the lowest terms, in a series 
whose higher members attain a very great development in 
certain animals, though their precise function is in many 
cases obscure. The homology of the tactile corpuscles with 
the Pacinian bodies appears, from what has been said, to be 
clear. What are the Pacinian bodies? Mr. Bowman, in his 
article on this subject in the Cyclopedia of Anatomy, will 
not decide upon their function, but points out their close simi- 
larity to certain bodies described by Savi in the Torpedo, 
and subsequently more fully described by Leydig (Beitrage 
zur Anat. d. Rochen. u. Haie.). These are capsules of homo- 


in theirlong diameter, and possess only one or two “ capsules,” with a pro- 
portionally large inner mass. In the Duck they are to be met with in great 
numbers in the skin of the beak, especially in the ridged portion at its 
edges. Here the Pacinian bodies, often very small (1-400th of an inch), 
lie immediately under the epidermis, with their long diameters more or less 
parallel to the surface; and the nerves are related to them, just in the 
same manner as those of the fingers are to the tactile corpuscle. It is dif- 
ficult to suppose that they have not here some special reference to the sense 
of touch. 

* Compare Strahl. Miill. Archiv, 1848, who gives a similar account of 
the structure of the layers. 


6 ON THE CORPUSCULA TACTUS. 


‘geneous connective tissue, containing a semi-solid gelatinous 
substance, and inclosing a knob-like process ; the termination 
of the stalk of the vesicle. A nervous bundle passes through 
the stalk, accompanied by a vessel, and branches out in the 
knob ; its fibres become pale and terminate here, not passing 
through as Savi stated. (Diag. C.) 

In the Rays and Sharks, bodies precisely similar to these, 
open by a tubular neck upon the outer surface of the skin. In 
the Sharks they have no special external hard capsule, while 
in the Rays they are provided with such acapsule, composed 
of condensed connective tissue. (Diag. D. E.) 

In the osseous Fishes, ampullz, similar to these, connected 
together by a longitudinal tube open on the sides of the body 
along the so-called lateral line. ‘The systems of each side are 
connected by a transverse tube which passes over the occiput. 
In the Sharks and Rays, organs of an exactly similar nature 
form a system of ramifying tubes in the head and over the 
sides of the body. These organs have hitherto been known as 
the ‘ muciparous canals ;” though, as Leydig has well shown, 
they contain a semi-solid gelatinous material, and have nothing 
to do with the mucus of the skin, which is formed by the 
altered epidermic layer. As Leydig has pointed out, then— 
the Pucinian bodies, the Savian bodies, and the so-called 
muciparous canals of osseous and cartilaginous fishes are 
homologous organs, and form a series, whose lowest term, if 
Wagner’s conclusion be correct, is formed by the corpuscula 
tactus. What is the highest term? In the most complex am- 
pulla, or muciparous canal, of a Ray or Shark, we find—1. ex- 
ternally a thick coat, composed of condensed connective tissue ; 
2, a nervous twig penetrating this, and passing to—8. an internal 
delicate sac, which contains a gelatinous matter, communicates 
with the exterior, and is lined by a layer of cells continuous 
with the epidermis : on the walls of this the vessels and nerves 
terminate. Now, we have only to conceive a single hair, 
developed within one of these ampulla and taking the place 
of the clear gelatinous matter, to have a vibrissa, such as is 
met with in almost all the Mammalia about the lip and eye- 
brow (see Diagr. F); and I conceive that the vibrisse are, in 
fact, the most complex and fully developed forms of this series 
of cutaneous organs.* Now, the vibrisse are, without doubt, 
delicate ,organs of touch, and the mucous canals of Fishes 
appear to be very probably of the same nature; but when we 


* The auditory labyrinth is constructed on precisely the sameplan as the 
muciparous canals of fishes, and the eye on that of a vibrissa, as might 
realily be demonstrated ; so that all the organs of sense are to be regarded 
as modifications of one and the same plan. 


ON THE CORPUSCULA TACTUS. 7 


come to the Savian and Pacinian bodies, and to the Corpuscula 
tactus, two possibilities arise—either they may be still the 
instruments of a modified sense of touch, or they may be 
merely rudimentary representatives of the more completely 
formed organs. At present there appears to be no sufficient 
evidence to decide this point; and | would merely wish to 
draw attention to the fact, that these organs are not isolated 
structures, but form a series, with the function of whose 
highest members only, we are at present fully acquainted. 


Some Observations on the Ittumination of TRANSPARENT 
Ossects. By Grorce Raney, M.R.C.S., Demonstrator 
of Anatomy and Microscopic Anatomy at St. Thomas’s 
Hospital. 


Ir is observed by an excellent optician and writer on the 
microscope that “the manner in which an object is lighted is 
second in importance only to the excellence of the glass 
through which it is seen. In the investigating of any new or 
unknown object it should be viewed in turns by every descrip- 
tion of light, direct and oblique, as a transparent object and 
as an opaque object, with strong and with faint light, with 
large angular pencils and with small angular pencils, thrown 
in all possible directions. Every change will probably de- 
velop some new fact in reference to the structure of the 
object.” These remarks are so true that it is not too much to 
say that the power and perfection of the best modern lenses 
cannot be correctly estimated or fully appreciated unless em- 
ployed in conjunction with the best modes of illumination ; 
nor can the best methods of illumination be properly tested 
without the best lenses, But, in proportion as these optical 
inventions, like most other contrivances, approach perfection, 
so do the difficulty and care necessary in using them increase ; 
and hence, to secure their full advantage, it becomes the more 
necessary to possess a certain amount of knowledge both of 
their construction and their action. 

In the judging of optical instruments it is of importance that 
appropriate objects should be examined — namely, such as 
have upon them the most delicate, though distinct markings. 

I know of no microscopic specimen better adapted for test- 
ing the excellency both of lenses and condensers than the one 
now generally in use for this purpose—the Pleurosigma 
angulatum. 

I shall frequently have occasion in the following remarks to 
allude to Gillett’s condenser and to Wenham’s paraboloid, but 


8 ON THE ILLUMINATION OF TRANSPARENT OBJECTS. 


as these excellent contrivances have been in use for some time, 
and therefore are generally known, it would be superfluous in 
me to describe their several parts, or to do more than simply 
to name them. 

Nothing can show the advantages of the improved method 
of illumination better than a careful examination of the object 
just named, first as illuminated in the ordinary way, and then 
as illuminated in the improved one; afterwards contrasting 
the appearances which it presents under these kinds of illumi- 
nation. : 

If the Pleurosigma angulatum be examined with a lens of 
1-8th inch focus, and 150° angular aperture, by good day- 
light reflected upon it by a plane or concave mirror in the 
ordinary way, little more than the mere outline of the object 
will be visible. Nor will any advantage be gained by in- 
creasing the magnifying power of the microscope by the 
employment of the deeper eye-pieces. On the contrary, these 
are of more harm than benefit, in consequence of the diminu- 
tion of light which they occasion. If, now, Gillett’s con- 
denser be substituted for the mirror, and the light be admitted 
only through the four or five smaller apertures of the revoly- 
ing diaphragm of the condenser, so that the central rays only 
of the pencil of light pass through the object, no dots or lines 
will be seen upon it, but its appearance will be the same as 
when the mirror was used; nor will the deeper eye-pieces be 
of any use. Of course I am speaking of the condenser when 
properly centered and adjusted. The non-appearance of 
markings on the Pleurosigma under this kind of illumination 
is differently explained. That it is not due to a deficiency of 
_ light is evident from the following experiment. If one of 
these apertures be stopped, and the diaphragm be so placed 
that only a small quantity of light can pass obliquely through 
the condenser by the next hole, distinct parallel lines are 
made apparent, although the field of view is much darker than 
before. And that it is notin this instance caused by an excess 
of light, as imagined by some microscropists, is certain from 
the following fact. Turn the revolving diaphragm so that the 
pencil of light passing through the condenser is just sufficient 
to render the markings on this object visible ; afterwards bring 
successively the larger apertures under the condenser, and it 
will be seen that the marking, in the place of becoming less 
apparent as the diameter of the pencil of light increases, 
becomes more so. 

From these facts it is obvious that the appearance or non- 
appearance of lines on the Pleurosigma is altogether inde- 
pendent of the quantity of light, and due only to the direction 


ON THE ILLUMINATION OF TRANSPARENT OBJECTS. 9 


in which the rays are made to fall upon this object. As it 
has been shown that the rays nearly perpendicular, called 
direct rays in contradistinction to the oblique ones, are of no 
use in the illumination of the object in question, and as its 
marking is rendered perfectly distinct by oblique light, it 
is evident that the most proper illumination in this case is 
that in which the central part of the pencil of light is cut off 
by a stop from the object, and only the oblique rays allowed 
to pass through it. These ends are fully attained by Mr. 
Gillett’s condenser: and, as by this contrivance the oblique 
rays can be thrown equally on all sides of the minutest par- 
ticles, shadows are prevented ; and markings, which, when 
illuminated by oblique light only on one side, appear as lines, 
are in this way resolved into their component dots. 

It now remains to show in what manner oblique light acts 
in developing structures which cannot be seen by nearly per- 
pendicular rays. I may observe that it is not a question of 
degrees of distinctness that | am considering, but the fact that 
parts, which are perfectly distinct when examined by one 
kind of illumination, are totally invisible when examined by 
another kind. 

The explanation of this fact seems to be deducible from the 
following considerations. 

Suppose a part to be made up of two substances intimately 
connected, though distinct from each other, and both defi- 
nitely arranged, whose refractive powers differ so little that 
they cannot be distinguished from one another under the 
microscope by the slight difference in their refraction of the 
light passing through them. This is, I believe, the condition 
of the Pleurosigma angulatum and other objects of a similar 
kind. Now, if the light, by any kind of illumination, can be 
prevented passing through one of these substances—the one 
having the greater refractive power—whilst it passes freely 
through the other, they will then become perfectly distin- 
guishable, the one appearing dark, the other light. This is 
what seems to take place when such objects as the one in 
question are illuminated by oblique light; for a ray of light 
cannot pass out of a denser into a rarer medium if the angle 
of incidence exceed a certain limit, and this limit is different 
in substances of different refractive powers. Thus all rays 
incident on water, at an angle greater than 48° 36’, having to 
pass from it into air will not be refracted, but reflected. In 
the same way, all rays incident on glass, at an angle greater 
than 41° 49’, and passing from it into air, will not be re- 
fracted, but suffer total reflection. Hence, applying these 
facts to the Pleurosigma, 1 think that it admits of but little 


10 ON THE ILLUMINATION OF TRANSPARENT OBJECTS. 


doubt that the dots appear dark only because the light 
beneath falling upon them at an angle greater than that at ~ 
which all refraction ceases, and total reflection begins, cannot 
be transmitted, and hence these dots are seen as opaque 
bodies intercepting the passage of the light to the eye; 
whilst, on the contrary, the other material, having a lower 
refractive power, and therefore allowing all the oblique rays 
incident upon it at the same angle to pass through it, will 
necessarily appear bright. 

The correctness of this conclusion will appear more pro- 
bable when it is recollected that these two substances are dis- 
tinguishable not by the one refracting the light differently to 
the other, but by the fact of one refracting it, and the other 
not; the former appearing bright and transparent, the latter 
dark and opaque. 

As respects the non-appearance of the markings under 
direct illumination, it may be observed that, as the rays in . 
this instance may nearly all be supposed to be incident upon 
the object at an angle less than that at which refraction ceases, 
they would be refracted by both substances nearly in the same 
degree, and therefore each would appear to be transparent, and 
the whole almost homogeneous. 

These few facts show that, when all such objects as the 
Pleurosigma are illuminated by oblique rays, they must be 
examined by lenses which admit a large pencil of light, that 
is, have a large angle of aperture, in order that an allowance 
may be made for the diminished quantity of light which pene- 
trates the object and enters the eye, in consequence of the 
total reflection from the lower surface of the dots. 

Having considered the class of objects best fitted to display 
the effects of oblique illumination, | will now consider those 
which are best seen by light passing through them almost 
perpendicularly. 

Although oblique light answers so well in the instances | 
have adduced, there are some structures and objects for which 
it is totally unfit, and which can only be successfully examined 
by rays passing through them almost perpendicularly, that is, 
by direct light. 

Amongst this class of objects are all those which strongly 
refract light, either from their density or spherical figure, as, 
for instance, most recent structures, either animal or vegetable, 
these consisting chiefly of corpuscles, and highly-refractive 
particles of various forms and sizes, 

The reason why such objects cannot be*seen when illumi- 
nated by rays falling upon them very obliquely, but are dis- 
tinct when illuminated by those which fall upon them almost 


ON THE ILLUMINATION OF TRANSPARENT OBJECTS. 11 


perpendicularly, will, I think, be apparent from a few conside- 
rations respecting the undulatory theory of light. According 
to this theory, the phenomena of refraction are due to vi- 
brations produced in an elastic medium occupying the inter- 
vals between the particles of all transparent substances by a 
force proceeding from a luminous body ; and the elasticity of 
this medium is less in proportion to the refractive power of 
every transparent substance; or, in other words, the greater 
the refractive power of any substance the greater also will 
be the force required to excite undulations in the less elastic 
medium diffused through it. Hence, as the effect of the 
same force acting upon a resisting medium is proportional 
to the direction in which it acts, being at its maximum when 
the line of the force is perpendicular to that of the resistance, 
and at its minimum when the angle of inclination is upon the 
point of vanishing, it must be clear, that light falling obliquely 
upon a transparent surface will exert less power in producing 
the effects of refraction than if it fell perpendicularly ; so that 
when the rays of light fall very obliquely upon a highly- 
refractive substance, their effect will be too feeble to excite its 
condensed vibratory medium into undulations, and therefore 
the rays will simply pass by it, producing at its border the 
effects of interference of light. 

This is precisely what takes place when oblique light is 
employed to illuminate objects possessing a very high refrac- 
tive power; whilst rays falling nearly perpendicularly upon 
the same objects, and thus acting upon them in a direction 
the most favourable for producing the effects of refraction, 
penetrate, as it were, their substance, and render their structure 
apparent in all its detail. 

Though there are these two classes of objects, one requiring 
for their illumination oblique rays, and the other nearly per- 
pendicular ones, yet the majority of compound organs require 
both kinds of light. Many of them are structures which, though 
they may appear most beautiful under direct illumination, 
will, by oblique light, be made to reveal something in their 
composition which would have remained concealed without 
this light. . 

Structures, if examined properly, should be subjected to a 
kind of microscopic analysis, in order that nothing in their 
composition may be overlooked. 

Having shown some of the advantages of the present 
methods of illuminating microscopic objects, | will consider 
some defects in these methods, which have been in a great 
measure overlooked, and also the best way of obviating them. 

This will be best done by carefully observing the effects of 


12 ON THE ILLUMINATION OF TRANSPARENT OBJECTS. 


different modes of illumination upon those microscopic objects 
whose precise form and optical properties are known. 

For this purpose I will first describe the appearances pre- 
sented by microscopic globules of mercury of different sizes 
when illuminated by Gillett’s condenser and Wenbam’s para- 
boloid. 

Such globules can easily be obtained by condensing the 
vapour of boiling mercury upon a piece of glass, and then 
causing some of the particles to run together, with the point of 
a needle. 

If one of these globules, about 1-300th of an inch in 
diameter, be examined by a lens of half-inch focus, and illu- 
minated by Gillett’s condenser, all rays coming from other 
sources being completely cut off, and the light admitted 
only through the smallest aperture of the revolving diaphragm, 
it will present, when the margin is in focus, a circular, darkish 
surface with an obscure ill-defined light in the centre; but 
when the nearest surface is brought into focus, the central 
spot of light will become distinct and well defined. If the 
diaphragm be revolved, so as to bring under the condenser 
the larger apertures, the size of the central spots of light will 
gradually increase in proportion to the size of the apertures. 
If, now, one of the stops be brought under the centre of the 
condenser there will be seen on this globule, in the middle 
of the illuminated circular space, a distinct image of the 
stop, which can be recognised by the cross-bar which joins the 
circular disk to the edge of the opening; and these can further 
be shown to be the image of the parts just mentioned by 
revolving the condenser, when they will be seen to move 
and to change their direction and position according to that 
of the condenser, If there be several globules of different 
sizes in the field of view, every one of them will have an 
image of the stop uponit. Of course in proportion as the glo- 
bules are more minute, the images will be less recognizable, 
and on those about 1-1000th of an inch in diameter they can be 
distinguished only as a very minute circular spot with a dark 
point in its centre. Globules much smaller than these 
present only a minute point of light in their centre; and the 
smaller, those about 1-15000th of an inch, appear entirely 
dark. However, when higher magnifying powers are em- 
ployed, an image of the stop can be distinguished on globules 
1-4800th of an inch in diameter, If any of the globules 
have been a little compressed by the piece of thin glass 
placed upon them, to keep them from dust, so that their 
spherical figure is destroyed, no image will be formed on 
them; but the flattened central space, when the stop is under 


ON THE ILLUMINATION OF TRANSPARENT OBJECTS. 13 


the condenser, will be faintly illuminated ; if the place of the 
stop, however, be occupied by one of the apertures, it will 
be very brightly illuminated. Such are the appearances of 
globules of mercury under the higher power of the mi- 
croscope. But if they are examined by a lens of lower 
power—one-inch focus, with one of the larger stops under 
the condenser—they will appear on a dark ground, as when 
illuminated by Wenham’s paraboloid. There will be a well- 
defined ring of light around each globule, and at its centre an 
image of a stop; the only difference in their appearance as 
illuminated by these two instruments being this, that when 
the latter is employed, the light is a little brighter, and that in 
the place of the image of a stop in the centre of the globules 
there is avery distinct one at the end of the paraboloid, and of 
the cross-bar placed within the tube to support the central disk, 
which can be seen to move and change its direction when the 
instrument is made to revolve. 


( To be continued.) 


Paper on the Discovery of Quinine and QurntpinE (8. Quinine) 
in the Urine of Patients under medical treatment with the 
Salts of these mixed Alkaloids. By W. Biro Heraratn, 
M.D., Bristol. 


Ir has long been a favourite problem with the scientific pro- 
fessional man to trace the course of remedies in the system of 
the patient under his care, and to know what has become of 
the various substances which he might have administered 
during the treatment of the disease. 

Whilst some of these remedies have been proved to exert 
a chemical change upon the circulating medium, and to add 
some of their elements to the blood for the permanent benefit 
of the individual, others, on the contrary, make but a tem- 
porary sojourn in the vessels of the body, circulating with the 
blood for a longer or shorter period, but being eventually 
expelled and eliminated from it at different outlets and by 
various glandular apparatus. 

Some of these substances being more or less altered in 
chemical composition, in consequence of having been sub- 
jected to the various processes of vital chemistry during their 
transit through the system; whilst others, having experienced 
no alteration in their constitution, but having resisted all the 
destructive and converting powers of the animal laboratory, 
have been by various means again separated from the ex- 


14 HERAPATH ON THE DISCOVERY OF QUININE, &c. 


cretions by the physiological and pathological chemist, in 
their pristine state of purity. 

It has recently been somewhat more than a conjecture that, 
in common with others of the vegetable alkaloids, quinine may 
be included in the latter class of remedial agents ; and several 
methods of discovering its presence have emanated from dif- 
ferent scientific observers. It has been occasionally traced in 
the urine of patients suffering from intermittent fever, to 
whom large doses of quinine have been necessarily admi- 
nistered. However, the nature of the tests hitherto employed, 
and the various processes adopted, require large quantities 
of the fluid for examination, and the imperfection of the 
evidence resulting from the experiment still throws consi- 
derable doubt upon the value of the conclusions arrived at. 
It is merely necessary to allude to tannic acid and tincture 
of iodine as the usual tests employed, both being very far 
from efficient means of detecting minute quantities of quinine 
in organic fluids. 

Having been struck with the facility of application and the 
extreme delicacy of the re-action of polarised light, when 
going through the series of experiments upon the sulphate of 
jodo-quinine (Phil. Mag., March 1852, and September of the 
same year), I determined upon attempting to bring this 
method practically in use, for the detection of minute quan- 
tities of quinine in the excretions or animal fluids. 

After more or less success by different methods of experi- 
menting, I have at length discovered a process by which it is 
possible to obtain demonstrative evidence of the presence of 
quinine, even if in quantities not exceeding the 1-100,000th 
part of a grain; in fact, in traces so exceedingly minute that 
they would be perfectly inappreciable by any other process. 
The same method (by a slight modification) has also enabled 
me to prove the fact, that quinidine escapes from the system 
by the kidneys in an unaltered state, which, as far as | am 
aware, has not hitherto been observed, although it might bave 
been almost assumed, from the great analogical resemblance 
existing between these alkaloids. 

The subject furnishing the urine for examination was a man 
suffering from tetanus, in consequence of an injury to the 
great toe. Amputation was performed at the Bristol In- 
firmary by Mr. Morgan. The patients name was R. Alex- 
ander. My pupil kindly procured the specimen for me. 

The tetanic symptoms were at first treated by the exhibition 
of 5 grains of the disulphates of quinine (and quinidine), 
with half a grain of canabis indica, every three hours. He 
consequently took 40 grains of the mixed disulphates in the 
period of 24 hours. 


HERAPATH ON THE DISCOVERY OF QUININE, &e. 15 


The urine had a greenish-yellow appearance, and, upon 
standing, it deposited a brownish-yellow sediment; the urine 
possessed a slightly acid re-action, and had a Sp. G. 1-032. 

The sediment examined by the microscope showed prisms 
and lozenges of uric acid, together with amorphous urate of 
ammonia. 

The deposit treated upon the field of the microscope with 
ammonia instantly became changed ; the crystals of uric acid 
were rendered more clearly defined in consequence of the 
solution of the amorphous urates. The phosphate of ammonia 
and magnesia was subsequently deposited upon the slide as 
a cloudy mass when examined by the unassisted vision, but 
as a magma of very minute radiating acicule when magnified 
60 diameters. 

The fluid urine was cautiously decanted from the amorphous 
and crystalline deposits. 

(A) Half a pint of this urine was treated with liquor 
potasse until decidedly alkaline; it was then repeatedly agi- 
tated with pure washed ether; the ethereal solution having 
had time to separate by repose, was carefully removed by a 
pipette ; and having been transferred to a counterpoised test- 
tube, it was evaporated to dryness in a warm-water bath; the 
residue weighed 0-79 grain after being kept at 212°, until no 
further loss of weight occurred. 

(B) A magma of phosphates and adherent alkaloid still 
remained above the urinous substratum; this was also re- 
moved by a pipette, and transferred to a porcelain capsule ; 
evaporated to dryness at 212°, and this residue exhausted by 
ether, the ethereal solution evaporated to dryness by a warm- 
water bath as before, and the residue dried at 212° gave ‘61 gr. 
additional alkaloid. 

Therefore -79* + -61°— 1:4 grains of alkaloids were ob- 
tained by these two operations from the 8 fluid ounces of urine. 

Now, to determine if it contained quinine, the following 
process was followed :— 

Test fluid—A mixture of 3 drachms of pure acetic acid, 
with 1 drachm of alcohol, and to these were added 6 drops of 
diluted sulphuric acid (1 to 9). 

One drop of this test fluid is to be placed on a glass slide, 
and the merest atom of the alkaloid added; time given for 
solution to take place; then, upon the tip of a very fine glass 
rod, a very minute drop of tincture of iodine added: if quinine 
be present, the first effect is the production of the yellow or 
cinnamon-brown coloured compound of iodine and quinine, 
which shows itself as a small circular spot, whilst the alcohol 
separates in little drops, which, by a sort of repulsive move- 


16  HERAPATH ON THE DISCOVERY OF QUININE, &c. 


ment, drive the fluid away: after a time the acid liquid again 
flows over the spot, and the polarising crystals of sulphate of 
iodo-quinine are slowly produced in beautiful rosettes ; this 
experiment succeeds best without the aid of heat. 

To render these crystals evident, it merely remains to bring 
the glass slide upon the field of the microscope (having 2-inch 
objective and lowest power eye-piece), with the selenite stage 
and single tourmaline beneath it: instantly the crystals assume 
the two complementary colours of the stage; red and green, 
supposing the pink stage is employed ; or blue and yellow, pro- 
vided that the blue selenite is made use of—all those crystals at 
right angles to the plane of the tourmaline producing that tint 
which an analysing plate of tourmaline would produce when 
at right angles to the polarising plate; whilst those at 90° to 
these educe the complementary tint, in the same manner as 
the analysing plate would have done if it had been revolved 
through an arc of 90°. : 

This test is so ready of application, and so delicate, that it 
must become the test for quinine.—( Vide Pl. I. figs. 1 and 2.) 
Not only do these peculiar crystals act in the way just related, 
but they may be easily proved to possess the whole of the 
optical properties of that remarkable salt of quinine, so fully 
described by me in the Phil. Mag. for March, 1852; and the 
chemical analysis of which was published in the number for 
September of the same year. In fact, these crystals are per- 
fectly identical with the sulphate of iodo-quinine in every 
respect. 

To test for quinidine it is merely necessary to allow the 
drop of acid solution to evaporate spontaneously to dryness 
upon the glass slide (before and without the addition of 
iodine), and to examine the crystalline mass by two tour- 
malines crossed at right angles, and without the selenite 
stage ; immediately little circular disks of white, with a well- 
defined black cross very vividly shown, start into existence. 
should quinidine be present even in minute quantities. Fig. 3. 
This fig. was drawn from a slide prepared by the author from 
the urine of the same patient ; about 1-20th part of a grain of 
the etherial extract was used by him in the manner described. 

This is generally the case if “ hospital quinine ” or that of 
the British Alkaloid Company has been employed: these 
drugs severally contain a very large per centage of quinidine ; 
the former at least 50, the latter about 20 per cent. But 
Howard’s di-sulphate of quinine scarcely contains 5 per cent. 
of quinidine, according to my experiments. These substances 
are easily separated, in consequence of the much greater solu- 
bility of the di-sulphate of quinidine in cold water, thus— 


HERAPATH ON THE DISCOVERY OF QUININE, &c. 17 


One part of di-sulphate of quinine requires 740 parts water, at 60°. 
One part of di-sulphate of quinidine requires 340 parts water, at 55°. 


so that the latter salt is more than twice as soluble as the 
former. 

If we employ the selenite stage in examining this object, 
depicted at fig. 3, we obtain one of the most gorgeous ap- 
pearances in the whole domain of the polarising microscope 
—the black cross at once disappears, and is replaced by 
one which consists of two colours, being divided into a cross 
with a red and a green fringe, whilst the four intermediate 
sectors are of a gorgeous orange yellow: these appearances 
alter upon the revolution of the analysing plate of tourmaline. 
When the blue stage is employed, the cross will assume a 
blue or a yellow hue, according to the position of the ana- 
lysing plate. 

These phenomena are analogous to those exhibited by cer- 
tain crystals of boracic acid, and also by the circular disks of 
salicine (prepared by fusion*), the difference being that the 
salts of quinidine have more intense depolarising powers than 
either of the other substances; and the mode of formation 
effectually excludes these from consideration. Quinine pre- 
pared in the same manner as the quinidine has a very dif- 
ferent mode of crystallization; but it occasionally presents 
circular corneous plates, also exhibiting the black cross and 
white sectors, but not with one-tenth part of the brilliancy, 
which of course readily enables us to discriminate the two. 

Having shown in my previous papers that none of the 
vegetable alkaloids, when treated with sulphuric acid and 
iodine, possess the power of forming crystalline compounds 
of similar properties, and these artificial quinine tourmalines 
being pre-eminent in their action on light, it follows that the 
existence of these crystals is a demonstration of the presence of 
quinine. 

It has also been proved by me, that quinidine (6 Quinine) 
cannot produce them, therefore we perceive that this alkaloid 
passes out of the system without experiencing any elementary 
change. 

One subject is worthy of remark: the patient was taking 
40 grains of the di-sulphates of quinine (and quinidine) ; there 
were found 1:4 grain of alkaloids, which would be equivalent 
to 1884 of the di-sulphate; and if the patient voided three 
pints of urine in 24 hours, we should only account for 11°304 
grains of the remedy employed, leaving a deficiency of 30 
grains nearly, either to be assimilated by the body or to be 


* T am indebted to my friend Mr. John Thwaites for this fact. 
VOL, IT. Cc 


18 HERAPATH ON THE DISCOVERY OF QUININE, &c. 


destroyed in its transit through the vascular system, or lost 
from other causes. 

It would be interesting to undertake a series of experiments 
to determine whether other excretions of the patient contain 
this remedy, and also to discover what length of time elapses 
after ingestion, before all evidence of its elimination by the 
kidneys ceases : this being done, we may be in a position to say 
what the medical equivalent of quinine may be ina given disease. 


On the Binocutar Microscope. By Prof. J. L. Ripe tr. 
Univ. La., New Orleans. Read before the American 
Association for the Advancement of Science July 30, 1853 ; 
Cleveland Meeting. (Communicated for the London Quar- 
terly Journal of Microscopical Science, by the Author.) 


Ir is proper to premise that some brief notices of the bino- 
cular microscope (devised in 1851, constructed in 1852), 
have already appeared in Silliman’s ‘Fowunal and elsewhere. 
I now desire to submit a few remarks and explanations to the 
members of the Association ; and at the same time to exhibit 
different forms of the instrument, so that the members inter- 
ested in the microscope may form a definite opinion of the 
value and utility of the improvement. 

The following diagram (fig. 1) will serve to illustrate the 
method first dened antl put in practice. It shows as a longi- 
tudinal section of the position of the objective and the prisms 
for producing binocularity. 


O, represents the object to be seen. 

ie the objective combination, always brought as Dear as practicable to the prisms. 

A, A’, two isosceles rectangular prisms of fine glass, in contact by edges somewhat ground away. 
The light entering the prism A through the "objective, suffers internal reflection on the 
hypothenuse A, and emerges from the prism in the direction of B. Entering the prism B, 
it is restored to its original direction. So likewise that part of the luminous pencil entering 
the prism A’, emerges nearly parallel from the prism B’. The prisms B and B’ are adjustable 
to different distances apart, and have likewise an axial adjustment in the plane of the 
section represented; the first, that they may be made to correspond to the interval between 
the two eyes of the observer; the second, that the direction of the rays, travelling from 
each point of the object, through the prisms, may be such as will seem to the observer 
natural and unconstrained,—and with clear coincident fields. 


ON THE BINOCULAR MICROSCOPE. 19 


In the smaller instrument before you this arrangement is 
observed. Used without eye-pieces, it gives a stereoscopic 
and perfectly satisfactory result. This instrument was con- 
structed for a dissecting microscope; I use it with lenses 
whether plain, doublets, or achromatics, from 4 inch to 3 inches 
focal length. 

The image is erect and orthoscopic. Objects can be viewed 
as opaque or transparent, and there is attached to it a flexible 
pipe, connected with a delicate cylinder and piston, which, in 
one respect, is made equivalent to a third hand. ‘Tightening 
a screw, and taking the ivory termination of the flexible tube 
in the mouth, the focal distance of the instrument can be 
varied at pleasure with the breath. In very minute dissec- 
tions, where the two hands are simultaneously employed with 
hook and needle, { have found this method of holding a focus 
of the greatest utility and convenience. 

If over B and B' single oculars be placed, the binocular 
vision is found to be pseudoscopic ; that is, depressions appear 
as elevations, and elevations as depressions. With erecting 
or double eye-pieces, analogous to those of the terrestrial tele- 
scope, the vision again becomes orthoscopic. 

On this account, I prefer to reserve this form of instrument 
for use without eye-pieces, in the manner explained, and to 
construct the compound binocular microscope ona plan which 
I will soon explain. 

Binocular Magnifier.—\ have found that for the magnifying 
glasses, used by artists and naturalists,—glasses having a 
focal length of one or two inches and more, a less com- 
plex and more economical arrangement can be adopted, 
namely :— 

The reflecting surfaces A A’ and B B (fig. 1) can be sub- 
stituted by pieces of common looking-glass, or plate glass 
silvered. The first surface reflections are too faint to interfere 
materially with distinct definition. 

The two mirrors of the pair, on each side of the nose, are 
hinged together on the principle of the parallel rules. The 
whole arrangement is mounted something like a pair of spec- 
tacles, while the requisite lenses are adapted to be centrally 
attached when required, I regard the binocular magnifier as 
supplying a great desideratum to lar ge classes of persons pur- 
suing a great diversity of callings. 

The effects, so often prejudicial to vision, of inordinately 
using one eye are thus avoided. 

A perfectly natural relief, or definition of bodies in depth, 
as well as in extension, is thus attained. 


Binocular Compound Microscope.—In the larger instrument 
7 oe 
c2 


20 _ ON THE BINOCULAR MICROSCOPE. 


before you, only two prisms are used for subdividing the 
light after its passage through the objective, and for directing 
the luminous pencils to the separate oculars. In this case 
orthoscopic vision is produced by the ordinary single oculars. 
The light suffers one instead of two reflections, as in the in- 
strument before described. The arrangement of the prisms 
is shown in section below. 

Fig. 2. The internal reflection takes place 
; upon the two long sides, which are in 
opposition at a small angle, which 
admits of adjustment in the plane of 
the section shown, the lower termina- 
tion always remaining in contact. The 
light through the objective, which im- 
pinges upon a, is that part of it which 
enters the prism, refracted to the left, 
so that it meets with the reflecting 
surface 6. Suffering total reflection it 
emerges from the surface c, where, 
from the necessary identity of the 
immergent and emergent angles, it is 
refracted to the right, so as exactly to 
compensate for its previous refraction 
to the left. This implies that the 


o, the object to be seen. i 
1, the objective, above and near Upper and lower angles of the prism 


to which is shown the two prisms. are equal. 


In the instrument before you, these equal angles are 45°, 
The ray of light, in pursuing the path a, b,c, suffers a minute 
chromatic dispersion, inasmuch as by the refraction and dis- 
persion at a, the red, violet, &c., will be found somewhat sepa- 
rated at c; thereafter, in travelling in the direction c d to the 
ocular, the red and violet will move in parallel paths, so that 
no further dispersion will occur. Upon a close scrutiny into 
this matter, I find that it does not practically lessen the 
sharpness of definition, unless eye-pieces of unusually high 
power be made use of. The minimum limit of angular 
definition, perceptible by the human eye, is about 45 seconds 
of a degree (45"). The extreme dispersion occasioned by the 
prism as above, may be kept handsomely within this limit ; 
this can be shown both by calculation and experimental de- 
monstration. By making the equal angles of the prism 
85° or 86°, so that the immergence and emergence shall be at 
right angles to the glass planes, this theoretical dispersion 
can be avoided. But practically, in this case, the usefulness 
of the prism would be destroyed by the interference of light 
directly transmitted through, without reflection. 


ON THE BINOCULAR MICROSCOPE. 21 


Prisms with equal angles of 60° will probably be found as 
appropriate as any, 

It would be improper to consume much of your time in 
explaining the mechanical details of this instrument. The 
following sketches will assist you to comprehend the essential 
peculiarities of a plain, firm, comparatively simple stand, and 
with all the most important adjustments. 

Fig. 3 represents a side view of the instrument. The stage 
is immovable, being firmly 
supported, so as not to 
spring sensibly under con- 
siderable and sudden pres- 
sure: it extends 6 by 4 
inches, 

The optical parts are 
supported by a stout tri- 
angular gun- metal bar, 
bearing rack- work, and 
moving up and down by a 
cogged pinion, terminat- 
ing in large milled heads, 
one of which is shown at 
E. For the convenience 
of changing objectives, the 
arm carrying the optical 
apparatus has at P nearly 
a half revolution, so as to 
carry it off the stage. The 
prisms are at the bottom 
of a brass box at A. One 
of the oculars is seen, as 
fitting into an adjustable 
tube C. A small rectan- 
gular, equilateral prism is 
so mounted in a brass cap 
as to be slipped at pleasure over the eye-glass. This 
little prism is adjustable in the plane of the drawing, on an 
axis transverse to the plane, so as to erect the image seen, 
and at the same time allow of its being viewed at any inclina- 
tion between verticality and horizontality, which may be con- 
venient to the observer. It will be seen that the prism at A 
has the effect of erecting the image in one plane, while the 
small prism at D can be placed so as to erect it in the plane 
precisely tranverse. Thus the movement upon the stage will 
be seen through the instrument to be natural or erect ; a con- 
dition essential to the convenient manipulation or dissection 


22 _ ON THE BINOCULAR MICROSCOPE. 


of a microscopic object. M represents the position of a con- 
cave mirror or other apparatus for illuminating transparent 
objects. Two small mirrors will sometimes be found more 
satisfactory than one large one, as the operator can then easily 
secure a good light to each eye, which is sometimes difficult 
with a single mirror. 

Fig. 4 exhibits a back 
view ; the common letters, 
or letters common to both, 
referring to the same parts 
as in fig! 3. ThusCC are 
the adjustable tubes into 
which the oculars fit. 
These tubes are hung upon 
axes, so that their inclina- 
tion to each other may be 
varied ; and the whole ar- 
rangement slides at plea- 
sure, horizontally, in order 
to adapt the distance to 
the eyes of different ob- 
servers. BB are milled 
heads of screws for the 
adjustment of the inclina- 
tion of the prisms, as ex- 
plained in connexion with 
fig. 2. R isa brass tube 
surrounding the box in 
which plays the triangular 
cun-metal supporting bar, 
before explained. Concen- 
tric with R, and movable 
thereon, is N, a short brass tube carrying the illuminating 
apparatus. 

Let the observer using the instrument carefully illuminate 
the object to be seen; then, after adapting the lines of vision 
to the natural requirements of the pair of eyes, duly alligning 
and superposing the corresponding images, and carrying ren 
into corresponding parts of the two circles of light, as de- 
fined by the diaphragms of the oculars ; and, lastly, regu- 
lating the focal position of the object in reference to the 
objective, all of which can be readily accomplished by the 
various adjustments: let him now place two good eyes of 
equal power in the proper position near the eye-glasses, and a 
magnificent field will present itself to his sight. He seems 
to look through a circular window or port-hole—say two feet 


Fig. 4. 


ON THE BINOCULAR MICROSCOPE. 23 


off, and a foot in diameter ; ten to twenty inches beyond which 
his microscopic objects, perhaps seemingly hung in mid-air, 
stand out in all the boldness and perfection of relief, and defi- 
niteness of position in width and depth, which he has been 
accustomed to realize without glasses in the natural objects 
around him. 

It does not appear to him that any glass, or other artificial 
medium, is interposed between his eyes and the objects seen. 
The vision fatigues him no more than does a landscape, or the 
inspection of the implements and objects on the table before 
him. <A drop of water teeming with alge and living in- 
fusoria, looked into in this way for the first time, impresses 
upon the beholder, even though he be a veteran microscopist, 
a profound sense of the sublimity of Nature in her lesser 
spheres, and a vivid conciousness of beholding the microscopic 
world in a new and seemingly palpable condition. 

By varying the inclination to each other, of the luminous 
pencils entering each eye, the objects can be made to appear 
definitely nearer or further off, at pleasure. In these cases 
the parallax or apparent angle subtended by an object remains 
constant, while the apparent size varies, of course, with the 
apparent distance, 

Thus, a mite of a wheel animalcule, 1-100th of an inch 
long, will perhaps appear to be a foot off, and as large as a 
mouse; but bring the prisms nearer together, and tilt the 
oculars to correspond, and the image waxes marvellously im- 
mense, and taking a position perhaps apparently more than a 
hundred feet distant, the being, too small to be seen with 
naked eyes, vies with the great whale of the ocean in size; 
wearing an aspect more awful to behold than the savage 
beasts of the African forests; exhibiting a complex, transpa- 
rent structure, more unique and wonderful than the mind 
of man can well conceive. 

The instrument, with its firm stand, broad stage, and erect 
images, is pre-eininently adapted for use in prosecuting minute 
dissections, or the unravelling of minute structure of any kind, 
Opaque objects may be illuminated by the bull’s-eye con- 
denser; and transparent objects, by one or two concave 
mirrors, aided perhaps by two diaphragms or screens. At 
night two candles may be used conveniently with one mirror. 
To illuminate for the higher powers a single achromatic con- 
denser suflices. 

Almost any model or form of monocular compound mi- 
croscope extant can be modified to become binocular, on the 
principles here explained in connexion with fig. 2. In one 
respect it would be convenient to adopt the trunnion mount- 


24 ON THE BINOCULAR MICROSCOPE. 


ing; the whole instrument might be tilted, so as to use con- 
veniently the Wollaston camera lucida in drawing. But this 
would detract from the firmness and simplicity of structure, 
so essential in a dissecting microscope, and add materially to 
the cost, a circumstance of importance to some who might 
wish to possess it. As it is, the instrument can be readily 
braced up at an angle near 45°, at which angle Natchet’s 
camera lucida works in drawing with perfect satisfaction. 

If the same object be drawn as seen through each ocular 
respectively, a difference between the two drawings is per- 
ceptible, similar to that between match stereoscope pictures ; 
so that if these two drawings be viewed, each with the appro- 
priate eye, the natural relief of the object is reproduced. I 
have already suggested in ‘Silliman’s Journal’ the propriety 
of publishing such drawings, appropriately placed upon paper, 
in illustration of natural history and histology. 


r 


Additional Observations on the Diaromaceous Deposit of 
Mott. By Witram Gregory, M.D., F.R.S.E., Professor 


of Chemistry. 


In the paper published in the last No. of the Journal, I gave 
a list of 60 species of Diatoms observed in the Mull deposit, 
or rather in one portion of it, by the Rev. W. Smith, adding 
that I had myself, in other portions, seen not only all these, 
but others which Mr. Smith did not meet with. Since then 
I have examined with care several different portions of the 
deposit, which, as I mentioned, varies a good deal in the 
relative proportion of species in different parts, and have 
detected upwards of 30 additional forms, most of which I 
have been enabled easily to identify by the aid of Mr. Smith’s 
Synopsis. In mentioning my observations, I shall use the 
names given in that work ; not, however, meaning by this to 
assert, that all Mr. Smith’s species are true and permanent 
species, for this is not the opinion of that author himself; but 
only with a view to the subsequent identification of the ob- 
served forms with those so beautifully figured by Mr. West, 
and their comparison with forms from other localities. 

But before proceeding I have to apologize for, and to 
correct, several errata in the former paper, chiefly in the list 
of species. My absence on the continent prevented my seeing 
a proof; and for the same reason, the figures of the new form 
were not seen by me after they were engraved, and owing 
to their having been taken from hurried sketches never meant 
for publication, they are not such as I could have desired. 


————— 


lof, ee Ma 


GREGORY ON THE DIATOMACEOUS DEPOSIT OF MULL. 25 


Perhaps the best plan will be to repeat here the list of 
forms given in the former paper, and then to subjoin my new 
observations. ‘These forms were— 


1. Pinnularia major 31. Cymatopleura apiculata 
e acuminata 32. Cocconeis Thwaitesii 

3 - oblonga 39. 3 Placentula. 

4 ra viridis 34. Surirella Brightwellii 

5 » ‘divergens 35. _ biseriata 

6. a acuta, 36. Cymbella Helvetica 

He fy radiosa 37. > maculata 

8 oe mesolepta 38. 5 Scotica 

9 - interrupta 39, 95 affinis 
10 > Tabellaria 40, cuspidata 
ig if 5 gibba 41, Himantidium gracile, Kiitz. 
12. ps gracilis 42, 5 bidens, W.Sm. 
13. a lata 43. 5 pectinale, Kutz. 
14. alpina 44, 5 Arcus, Kiitz. 
15. Navicula serians 45. = majus, W. Sm. 
16. pa rhomboides 46. 55 undulatum, Ralfs 
ive BS ovalis 47. Tabellaria fenestrata, Kiitz. 
18. a dicephala 48, + ventricosa, Kiitz. 
19. ne firma 49, Epithemia turgida 
20. ” angustata 50. Pe gibba 
21. Gomphonema acuminatum 51. Eunotia gracilis 
22. » var. coronatum ey Ae tetraodon 
23. $3 Vibrio 538. <3 Diadema 
24, oe capitatum 54. Synedra capitata 
25. Amphora ovalis 55. oS bieeps 
26, Stauroneis Phoenicenteron. 56. gs “6 var. B recta* 
Qiks 5 gracilis 57. Fragilaria capucina, Kiitz. 
28. hs linearis 58. Orthosira nivalis, W. Sm. 
29. anceps 59. 3 orichalcea, W. Sm. 
30. Cymatopleura elliptica 60. Nitzschia sigmoidea.t 


With respect to the new form previously described, Mr. 
Smith has proposed, since my former paper was written, to 
call it, provisionally, EHunotia incisa (No. 61), the notches 
which it exhibits forming a very well marked character. The 
figures formerly given of the two modifications or varieties of 
this form not being satisfactory, I here give such as will better 
indicate their true character.t My reasons for including the 
two forms together are, first, that both invariably exhibit the 
notches ; secondly, that the number of striz appears to be the 

“same in both, while the general aspect undoubtedly is so; and 
thirdly, that many specimens occur in which one apex is 
narrow, as in fig. 1, while the other is rounded, as in fig. 2. 
I would add a remark with respect to a point which appears 


* T have added this variety as it was noticed in the former paper. 

+ This species was accidentally omitted from the former list. 

{ These figures will be given in the next number of the Microscopical 
Journal. 


26 GREGORY ON THE DIATOMACEOUS DEPOSIT OF MULL 


characteristic ; that while the form No. 1 is quite symmetrical, 
No. 2 very rarely, if ever, is so, one end being always broader 
than the other. From the greater width of No. 2, the striz 
are much more easily seen in that form than in No. 1. 

Since my paper was written, I have detected this form in 
one more deposit, besides the present one and that mentioned 
in my former paper as said to be from the banks of the Spey ; 
namely, in the-Bergmehl of Lillbaggsjon in Lapland. It is 
not so abundant there as in the Mull deposit; and while, in 
the latter, No. 1 is the more frequent-form, in the former, the 
Lapland earth, No. 2, is more common. 

1] shall now give a list of those additional forms observed 
by me, in a careful study of several different portions of the 
deposit, which can be readily referred to figures in Mr. Smith’s 
Synopsis. These are— 


62. Pinnularia nobilis 78. Surirella linearis 

63. + viridula * 79. Cymbella Ehrenbergii 
64. 43 cardinalis 80. Epithemia rupestris 
65. Navicula tumida 81. % ocellata 

66. 9 gibberula 82. 7s Sorex 

67. 5 Semen 83. Eunotia triodon 

68. - obtusa 84, 8 diodon 

69. Gomphonema dichotomum 85. Synedra Ulna 

70. oe constrictum 86. Cocconema lanceolatum 
71. Stauroneis dilatata 87. 55 cymbiforme 
72. Tryblionella marginata 88. “3 Cistula 

73. Cymatopleura Solea 89. Nitzschia Amphioxys 
74. Surirella splendida 90. Cyclotella Kiitzingiana 
(x 33 nobilis 91. < antiqua 

76. ‘ minuta 92. $5 Rotula. 

dvs “5 Craticula 


Of the above 27 forms, the only ones which do not entirely 
agree with Mr. Smith’s figures are those I have termed Navicula 
obtusa and Epithemia Sorex. The latter is nearer in form to 
EF. Musculus, but as that is a marine form, I have preferred 
the other name, provisionally. In my specimens this form is 
very scarce, but may be found more abundantly in others. 
As to N. obtusa, the form so named by me, of which I give 
figs., Nos. 3 and 4, is rather more like J. affinis, but is one 
half larger than either of the two as figured in the Synopsis. - 
As, however, LV. obtusa is said to occur in the Lough Mourne 
deposit, and as I find there the form here figured, precisely 
as in the Mull earth, and no other resembling it, 1 have chosen 
the name J. obtusa in the mean time. It is clearly distinct 
from all the Naviculz figured in the Synopsis, except perhaps 
the two just named. 

We have thus 88 distinct Diatomaceous forms (whether in 
all cases true species or not, is a matter for future decision) in 


v/s. 2% ate ee ee 


: 


: 


. 


GREGORY ON THE DIATOMACEOUS DEPOSIT OF MULL. 27 


this remarkable deposit. The study of it has led me to think 
it probable that several forms, at present separated, will have 
to be united; but our knowledge of Diatomaceous forms and 
of their modifications is not yet sufficient to enable us with 
certainty to classify them all. There is nothing, therefore, to 
be done, but to describe and accurately to fisnve, all such 
forms as appear distinct, and we shall thus in time me able to 
trace out the relations among them. This very deposit 
appears to me rich, not only in distinct forms, but in modi- 
fications of these, in several cases exactly intermediate between 
the figures of recorded species. To this part of the subject I 
shall return at a future time ; for the present, I confine myself 
to mentioning the forms which agree with the published 
figures. 

It will be observed, that 27 species and 2 genera, Cocco- 
nema and Cyclotella, have already been added to the former 
list. But I am quite sure that the number is not yet exhausted, 
for I have observed several well marked forms, which I cannot 
securely refer to any of those figured in the Synopsis, and 
which may probably, therefore, prove to be new to oe 
Among these are one or two Pinnularig; one or two Navicule 
one, perhaps two, Synedre ; one Nitzschia, possibly two; one 
which | take to be a Melosira, but for want of the 2nd volante 
of the Synopsis I cannot compare it with figures of the 
British species. The same remark applies to the genus 
Himantidium, of which Mr. Smith identified 6 well marked 
species, but of which, or of some allied forms, I have reason 
to think two, perhaps three more are present. I shall here- 
after describe and figure all such doubtful forms. 

For the present, 1 shall conclude with the description of a 
very distinct and well marked species of Pinnularia, on the 
specific character of which no doubts can be entertained, and 
which is therefore new to Britain, if not to science. This 
form I early noticed, but it was not till I had compared it with 
the figures in the Synopsis that I felt sure of its being different 
from all the forms in that work, as well as from all figures of 
Pinnularie known to me. In the Mull deposit, it occurs in 
all the different portions I have yet examined, but invariably 
very widely scattered, so that a good slide, rich in forms, 
seldom yields more than one or two individuals, and occa- 
sionally contains none at all. Hence, and from its small size, 
it is apt to be overlooked, except in a very minute and careful 
search. It is of course impossible for me to say whether this 
form have been already described as occurring in foreign 
countries, but as yet I have seen neither figure nor description 
to which it can be referred. I would propose, therefore, pro- 


28 GREGORY ON THE DIATOMACEOUS DEPOSIT OF MULL. 


visionally, to name it Pinnularia hebridensis ; and if any of 
your readers should recognise it as one already named, of 
course the earlier name must be adopted. 

Pinnularia hebridensis.—V. elliptical, narrow, almost rect- 
angular, with rounded ends, sometimes very slightly con- 
stricted in the middle, and sometimes very slightly acuminate 
at the apices. F. V. rectangular, with the corners slightly 
rounded. Length, from *00125 to +0025. Costa strong, 
distant, radiated at the middle, not nearly reaching central line, 
10 to 11 in -001. Habit stout, notwithstanding its narrow- 
ness, so that it seldom occurs fractured. The figures 5 and 6 
will give some idea of its aspect. 

The small size, for this is one of the smallest Pinnularia, 
combined with the strong distant costa, at once distinguish 
it from all those figured by Mr. Smith. I find in the late 
edition of Pritchard’s ‘Infusoria,’ a description of Staur- 
optera scalaris, Ehr., which has some points of agreement 
with the above, such as the small size and the distant costae. 
But the figure of the valve (Prichard, pl. xv., fig. 10) is very 
much broader, and the number of costa is said by Ehrenberg 
to be 12 in 1-1200, which is = 14 in ‘001, whereas my form 
has usually 10 only, sometimes only 9°5. Besides this it has 
not the pseudo-stauros which marks the genus Stauroptera of 
Ehrenberg, and the nature and form of the nodules and 
median line correspond exactly to those of Pinnularia alpina, 
while the arrangement of the costa is also very similar to 
what is seen in that species, only on a very small scale ; the 
form, however, is quite different. 

I have only to add that, hitherto, I have been unable to detect 
the presence of this form in any other deposit which I have 
had an opportunity of examining; and that if any of your 
readers can throw light on the subject, or has observed any 
other well marked species in the Mull deposit, I shall feel 
deeply indebted to them if they will make known their 
observations. I shall also be happy to supply observers with 
the material for their researches. 


( 29°) 


TRANSLATIONS, &c. 


On Cutaneous Diseases dependent upon Parasitic Growths. 
By Dr. B. Guppen. Abstracted from the ‘ Archiy fiir 
Physiolog. Heilkunde,’ Heft II. 1853. 


Porrigo appears under numerous external forms, to which 
special names have been assigned by many authors, and which 
have in fact been distributed in different classes, as if they had 
no mutual connexion. They all, however, have one common 
characteristic by which, as respects their origin, they are dis- 
tinguished as a group from other cutaneous diseases; this 
characteristic is the existence in them of Fungi, which were 
discovered by Schonlein (in Porrigo lupinosa), and their pre- 
sence subsequently confirmed by all observers. 

‘“*‘ We shall show, by a series of observations, that the me- 
dium, in which these Fungi find their nutriment, is the normal 
epidermis, and that those spots in it, which are more especially 
favourable for the reception of foreign particles, are, almost 
exclusively, the situations in which the vegetable formations 
germinate. From the borders of the organic life of the epi- 
dermis we shall trace the progressive growth of the parasites 
to the site of their development—the cut?s—and in thus tracing 
them shall be able to explain all the phenomena which occur 
in Porrigo, whether as the direct effect of the devouring 
parasitic growth, or as the consequence of the reaction set up 
on the part of the cutis in opposition to it. We shall, more- 
over, find reason to be convinced, that the Fung?, when trans- 
planted into a perfectly healthy man, take root ; and ultimately 
prove, that with their removal, in simple cases, the entire 
disease is cured. 

“ We will consider the two factors of our disease—Fungus 
and skin—in the first instance apart, although not without 
reference to their mutual relations :—- 

‘“‘T. Oval, transparent corpuscles, presenting sharp, dark 
outlines, and whose length and transverse diameter vary very 
much in proportion to the abundance of their nutriment, con- 
stitute the primitive form of the Fungus we are considering. 
In the air they readily dry up, but again swell out with con- 
siderable rapidity on the addition of water, although they do 
not burst. No nucleus is visible in these corpuscles. Whilst, 
not unfrequently, especially at a later stage, ‘‘ chlorophyll- 
granules” of a more or less yellow colour are developed within 
them, from a differentiation of the fluid contents ; and at the 


30 GUDDEN ON CUTANEOUS DISEASES. 


same time the outlines become paler. They vary, also, con- 
siderably in number, size, and shape. When they occur 
isolated, they present a deceptive resemblance to nuclei, and 
I fancy it is they which have been described as such by Fuchs 
and Bennett. 

“On the above described vesicles, there are developed, for 
the most part at the ends, but not unfrequently also on the 
sides, one or perhaps two bulgings, which increase in size, 
become constri¢ted at the base, sprout out again in a similar 
way, and constitute eas eo dichotomously branched rows 
of cells. In the meanwhile the older cells do not remain 
stationary. They grow, and, occasionally with a diminution 
in their width, increase in length, the outlines become pale, 
owing to the flattening the constrictions are removed, and tne 
moniliform strings are transformed into elongated, round fila- 
ments which continue to undergo greater and greater attenua- 
tion. At the same time they are capable of propagating, 
throw out spores on the sides, but ultimately becoming imper- 
ceptibly minute, and quite colourless, are lost in a molecular 
detritus. 

‘“‘ This is the mode of growth of the Fungus, when it is in no 
way interfered with, And the correctness of the exposition 
will be most readily shown by the assiduous examination of 
the root-sheaths of the hairs, but most convincingly when the 
Fungus in its earliest stages is successfully brought under the 
microscrope. Circumstances, however, will, of course, pro- 
duce many varieties. 

“In the common form, upon examination of the crumbling 
substance of the scabs of Porrigo lupinosa, it is well-known 
that the cells are seen to be scattered and separate, or only 
united by two or three together into short series In most 
cases, perhaps, this is owing merely to the preparation, for the 
less pressure and crushing is employed, and especially when 
very fine vertical sections are made, from scabs not too old, the 
more numerous and the longer are the rows of cells brought 
into view. Specimens also are not rare, in which the individual 
cells remain in contact with each other at the angles. Never- 
theless, I would not altogether deny the occurrence of a spon- 
taneous separation. ‘The supposition that such an occurrence 
does take place, is supported both by the readiness with 
which the cells may be separated, and also by the capability 
of each when isolated to propagate itself independently. This 
capability, of which I have satisfied myself by the examination 
of individual specimens, and the observation of preparations 
in which, among elongated pale cells, several rounded, yel- 
lowish, sharply defined ones appear, as it were, intercalated, 


GUDDEN ON CUTANEOUS DISEASES. Sl 


or, in the reverse case, where among some of the latter kind 
one or two of the former sort are interposed—proves that each 
cell is an individual plant, the development of which under 
favourable circumstances proceeds to the production of a my- 
celium such as has been described.” 

The author then proceeds to give a lengthened description 
of the hairs and follicles, and to point out their correspond- 
ence with the nails and their bed, but this it is needless to 
transcribe. From the nature of the fungus and from con- 
siderations drawn from the formation of the hair follicles, he 
deduces the following conclusions :— 

“‘ J. The more dry the skin, the more secure is the person 
against the invasion of the parasite. 

“2. With a similar condition of the epidermis, healthy and 
diseased persons are equally disposed to the attack; different 
morbid conditions coming under consideration only so far as 
they increase or diminish the conditions favourable to the 
growth of the fungus. 

“© 3. No part of the skin is, under all circumstances, entirely 
_ secure against these plants, but the hair follicles, and especially 
those on the head, are peculiarly adapted for their reception 
and propagation.” 

The author therefore denies that there is proof of the scro- 
fulous nature of Porrigo, and that its appearance is always 
preceded by a scrofulous exudation, and is of course still 
more opposed to the extraordinary assertion of Neukrantz of 
the identity of tubercle and Favus, as well as to its having 
any direct connexion with several other forms of strumous 
disease, with which it has often been associated. 

Simon states, that, in Favus, he never observed the Fungus 
extending to any distance within the hair follicle, in which 
Gruby also agrees with him. Whilst the latter observer in 
the hairs of the beard noticed between the root-sheath and the 
shaft, Fungi, the spores of which were minute, commonly 
round, and the myce/ium furnished with granules. He desig- 
nates this form, analogous to his Porrigophyta, under the name 
of Mentagrophyta. He also saw Fungi in Alopecia circum- 
seripta of the scalp. In his Phyto-alopecia the hair at its point 
of exit from the follicle is surrounded with a sheath composed 
of the fungi which extend to the height of 3-13/” up the 
shaft, and thence spread themselves over the neighbouring 
hairs. They consist of myce/ium threads and spores. The 
latter are tolerably minute, the round gs's¢- ss's0'" ;_ the oval 
troo-rtoo” long. In his Rhizophyto-alopecia the fungi are 
said to be developed in the root of the hair itself, to grow 
within its medulla and to occupy its interior. They consist 


32 GUDDEN ON CUTANEOUS DISEASES. 


only of spores of about the same diameter as the oval ones of 
the Phyto-alopecia and form for the most part moniliform 
strings, lying parallel with the axis of the hair, and causing 
the hairs to become grey and thick, and from the loss of their 
elasticity to be easily broken. Fungi in the interior of the 
hair are also described by Malmsten (Miller’s Arch. 1845). 

Dr. Gudden then describes a case of favus which he treated 
first by the removal of the scabs by soap and water, and 
afterwards by the application of a mixture of olive oil and 
croton oil followed by blistering with cantharides, and in 
which he at first thought he had obtained a cure, but was 
disappointed by seeing, after about 12 days from the healing 
of the vesicated surface, the disease reappear in the form of 
minute yellowish rings around each hair, which rings as 
shown by the microscope were composed of the fungus. The 
only part of the scalp which remained free from the growth 
was about the vertex where the hairs had been removed during 
the suppuration caused by the blister over the extent of about 
13 square inch. 

When once acquainted with the appearance of the hair- 
sheaths with the Fungi within them in Porrigo lupinosa (Favus), 
the author says that a look is sufficient to show the identity, 
with the latter, of the parasitic growth, found also in the hair- 
sheaths in Porrigo furfurans and other forms of Porrigo (not 
Porrigo decalvans, in which the author was unable to detect 
any parasitic growth). In these forms of Porrigo the fungus 
appears, from one reason or another, to be limited almost 
wholly to the root-sheath of the hair, and can only be detected 
when the root-sheath is extracted together with the hair. In 
ordinary cases where there is no inflammatory action present, 
the sheath does not usually come away with the hair when the 
latter is plucked out and the parasitic growth is therefore not 
to be seen, but Dr. Gudden states that by rubbing the part 
with croton oil so as to excite some degree of inflammation 
around the hairs, the root-sheath will come away and within 
it the fungoid growth will be readily perceived. The detec- 
tion of the fungus i is facilitated by immersing the scurfy scales 

together with the adherent hair follicles, removed from the 
scalp i in Porrige furfurans, in oil of turpentine, which acts more 
slowly in rendering the fungus transparent, than it does upon 
the horny tissue of the epidermis, &c. 

The various forms of Porrigo depend upon the individuality 
of the skin, and this is proved not only by the identity of the 
Fungus in the different forms, but also by their frequently 
observed coexistence, and the transitions from one form to 
another in the same individual. 


GUDDEN ON CUTANEOUS DISEASES. a 


The diagnosis, however, is, in all cases rendered certain by 
the finding of the Fungus as above described. Pityriasis, 
which is also caused by a parasitic growth, is an entirely 
different disease, and its fungus, as the author shows in a sub- 
sequent chapter, is not to be confounded in any way with that 
of Porrigo. The contagious property of Porrigo is shown to 
depend upon the Fungus alone: in proof of which the author 
describes numerous experiments made by himself and others. 

The cure proposed by the author, and which appears to have 
been successful in his hands, consists, first, in the loosening 
of the hair-sacs by the use of croton-oil frictions and the 
after application of an oil-poultice, and subsequently the 
plucking out of the hairs by means of tweezers, a prolonged 
and not very pleasant occupation, as it requires to be done 
with extreme care. Whether his plan possess any advantages 
over the old one of a pitch cap, this is not the place to 
decide ; it appears, however, that the disease cannot be cured, 
in the form of Favus at all events, without the eradication of 
the hairs together with their root-sheaths. 


On a Species of Firarta found in the Blood of the Domestic 
Doc. By MM. Grusy and O. Detaronp. Abstracted 
from the ‘ Comptes Rendus. Tom. xxxiv. p. 9. 1852. 


AFTER noticing that several observers — Schmitz, Baer, Va- 
lentin, Vogt, and Remak, from 1826 to 1842—had indicated 
the existence of Filarie, Monostomata, Distomata, and Infu- 
soria in the blood of Frogs, of certain Fishes, and of some 
Mollusca, the authors proceed to state that, in the year 1843, 
they were the first to announce the discovery of entozoa, 
of the genus Filaria, living in the blood of certain domestic 
dogs, and circulating with the globules of that fluid in all the 
vessels. Since that communication to the Academy, MM. 
Erdl and Mayer, in 1843; Hyrtl, Gros, and Ecker, in 1845 ; 
Chaussat and Wedl, in 1848; and M. Guérin Méneville, in 
1850, have established the fact of the presence of Hematozoa 
in the blood of the Field-Rat, of the Black Rat, of several Birds, 
and Fishes,—of the Crab, the River Mussel, the Earth-Worm, 
and the Silk-Worm. The present memoir contains more particu- 
larly the researches to which the authors had devoted them- 
selves for the last nine years relative to the worm living in the 
blood of certain domestic Dogs. The results at which they 
arrived may be shortly stated in their own words as follows :— 

1. The number of microscopic Filarig inhabiting the blood 
of certain dogs may be estimated approximately at from 

VOL, UL. D 


34 GRUBY AND DELAFOND ON THE DOMESTIC DOG. 


11,000 to about 224,000. The mean number, deduced from 
twenty dogs, was more than 52,000. 

2. The microscopic Filarie, having a diameter less than 
that of the blood discs, circulate in the most minute capilla- 
ries where the blood discs can find entrance. A drop of 
blood taken from these vessels, it does not signify at what 
part of the body, nor at what season of the year, contains these 
minute Hematozoa. 

3. The chyle and the lymph of dogs, whose blood contains 
microscopic Filarie, present none. 

4. Nor do any of the secretions or excretions. 

5. Nor in the dissection of twenty-eight dogs of different sorts 
and ages, and whose blood was known to hana been verminous 
for periods varying from several months to more than five 
years, and made with the utmost care, were any Filarie@ ever 
discovered in any of the tissues. Their proper habitat seems 
to i exclusively in-the blood-vessels. 

The authors calculate, from the examination of 480 dogs, 
a the blood in about oan or five per cent. is verminous. 

7. It is so more frequently in old and adult dogs than in 
young ones. 

8. The verminous condition seems to be irrespective of 
race, sex, or general habit of body. 

9. Even when most abundant, this condition of the blood 
does not seem to interfere with the instincts or muscular force 
of the animal. 

10. Nor is the constitution of the blood itself altered. 

11. Transfusion of verminous blood, deprived of fibrin, 
into sound animals, was not followed by any result. But, 

12. When unaltered verminous blood was thus injected, 
Filarie were found living in the animals experimented on, for 
more than three years, or until their natural death. 

13. Filarie, transfused with defibrinated blood into two 
Rabbits, lived in the blood of those animals for 89 days; after 
which time none could be found. 

14. Ina similar experiment with six Frogs, two of which 
already had #?/arie in their blood, the canine Filarie@ lived 
for eight days, during the whole of which time the blood discs 
of the Dog appeared unaltered among those of the Frog. On 
the ninth and tenth days the Dog’s blood discs haying become 
changed, the Filarie had disappeared, and tne Frogs died of a 
scorbutic malady, (!) 

15. Injected together with the blood into the serous cavities 
or cellular tissue of Dogs, in good health, the Filarie@ could 
not live in their new domicile. 

16. A verminous Dog, of one race, with a female not so 


0 


GRUBY AND DELAFOND ON THE DOMESTIC DOG. 35 


affected, of another, had offspring of which those belonging to 
the paternal race were verminous, and the others not. 

17. When the conditions were reversed, so was the result. 

18. But the Filarig in the blood of the descendants could 
not be detected till the dogs were five or six months old. 

The authors have also succeeded in finding in the vermin- 
ous blood of a dog which died in consequence of its being fed 
exclusively on food composed of gelatin, large worms, visible 
to the naked eye. They found six, of which four were females 
and two males, and they were lodged in a large clot occupy- 
ing the right ventricle of the heart. ‘The worms were white, 
from 0-5 to 0°75 inch long, and from 0-039 to 0-058 inch in 
diameter. They propose for this Hematozoon, the name of 
Filaria papillosa hematica canis domestici. 


Onthe Existence of SpERMAtozorps in certain Freshwater ALG. 
By Dr. H. Irztcsoun. Abstracted from the Annales d. 
Sciences Nat. Tom. xvii. p. 150. 


Hiruerto, among the Algae, the spores of which exhibit 
spontaneous movements (Alg. Zoosporées, Thur.), the genus 
Cutleria was the only one known to possess “ antheri- 
dia:” this genus, however, belongs to the group of Phzo- 
sporées ( Thur.), whilst those noticed by M. Itzigsobn, as pre- 
senting spermatozoids, all belong to the Chlorosporées ( Thur.). 
On the other hand, the active corpuscles, contained in the 
“ antheridia,” either in Cutleria, or in the Fucacex, very 
closely resemble the spores, properly so called, of those Alga, 
and, except in their cilia and their motility, have no analogy 
with the long known spermatozoids of Chara, of the Mus- 
cinez, and those of the Ferns, and Equisetacee. Should M. 
Itzigsohn’s observations prove to be correct, the Algae will 
present three distinct types of antherozoids:—1. Ciliated 
and motile zoospores (sporomorphes ciligeres et mobiles) ; 2. 
those of the Floridew, also resembling spores, but in which 
the presence of cilia and the existence of motility are still 
disputed points; 3. lastly, the vermiform antherozoids, with- 
out cilia, but very active, forming the subject of M. Itzigsohn’s 
communication, which is in the form of a letter to Mr. L. R. 
Tulasne. 

*“ The object of my communication,’ he says, ‘* is to an- 
nounce a discovery which I have recently made, of the ‘ spi- 
rozoids’ (spiralfiiden) of the freshwater Algae.” ‘“ My re- 
searches have been especially directed to Spiroyyra areta, 
Kiitz. About the time in which the well-known phenomenon 

pb 2 


36 ITZIGSOHN ON SPERMATOZOIDS. 


of conjugation is observed in this Conferva, the band-like 
endochrome of some of the filaments becomes condensed into 
quaternary globules. These minute spheres are at first of a 
bright green colour, which afterwards becomes paler, and 
finally turns into a greyish white. They frequently exhibit 
very distinct movements within the tube in which they are 
contained, and this motion becomes much more active when, 
from any cause, they have escaped from the parent cell. If 
one of these utricles be gently crushed between two glasses 
a mucous material is seen to escape, from the midst of which, 
after the lapse of a quarter or half an-hour, are disengaged an 
infinity of spiral filaments, each of which was originally con- 
tained in a parent cell. ‘These spirozoids are for the most 
part agglomerated or grouped into minute rounded masses, to 
which I propose to give the name of ‘ spermatospheres.’ At 
the end of eight to fifteen days, should they have been pre- 
served alive, the spirozoids have become much longer and 
larger, having at the same time retained the faculty of per- 
forming the most active movements. I have not, however, 
hitherto been able to discover any cilia, nor even an appreci- 
able terminal enlargement. ‘The development of these bodies 
within parent cells appears to me an indisputable fact; there 
can, therefore, be no question as to their not being Vibriones. 

*¢ Long ago I observed the formation of spermatosphéres in 
Vaucheria; in that genus they frequently occupy distinct 
compartments of the filaments of which the plant is consti- 
tuted, and are very large. M. Karsten has published a figure 
of them in the ‘ Botanische Zeitung ;? but he is wrong in 
regarding them as a morbid product of the Vaucheria. In 
form, the ‘ spermatozoids’ of Cladophora glomerata, on the 
contrary, are in all respects analogous to those of the Spz7ro- 
gyre. My observations upon this interesting subject are not 
yet concluded, although I feel fully assured of the exactitude 
of the results now transmitted. Spermatospheres are found 
also in Closterium and Gidogonium.” M. Itzigsohn concludes 
by saying, ‘‘it is manifest that the generation of spermatozoids 
in Spirogyra, Vaucheria, and other analogous Alga, casts 
considerable light upon that which takes place in the Lichens 
and Fungi.” 


Note on the Muscutar Srructure in Patupina Vivipara, and 
other GastTERopopa, by Lerynie. 


Accorpine to Leydig (S. and K. Zeitsch., Vol. ii., p. 191), 
the structure of the muscles in Helix, Bulimus, Caracolla, 
Paludina, and other gasteropoda, is the following :—The 


ee SS 


a Pink ahha it Ne) i Ai at 


LEYDIG ON MUSCULAR STRUCTURE. 37 


special elementary tissue of the muscles is a tube which is 
derived from a successive series of coalesced cells. The nuclei 
of these cells are, even in full-grown animals, to be seen in 
many of the muscles, occurring in some more numerously than 
in others; thus they are abundant in the muscular tubuli of 
the heart in Paludina, where they are 0-004” long, and 
besides this, in the red-coloured portion of the oviduct; they 
are rare again in the muscular tubuli of the foot. The form 
of the primitive muscular tubuli is always more or less cylin- 
drical and slightly compressed ; the former shape is seen in 
the muscular tubuli of the fleshy body of the excitant organ, 
the latter.in those of the foot. Moreover that they really are 
of a tubular nature, is convincingly shown when suitable 
transverse sections are treated with acetic acid, by which the 
contents are dissolved, or at least rendered more transparent, 
only the membrane of the tubes remaining. <A peculiarity of 
these muscular tubes consists in this, that they not unfre- 
quently divide, as may very frequently be seen in the heart of 
Paludina vivipara. The contents of these tubuli is, in most 
cases, a transparent, colourless, gelatinous substance, soluble 
in acetic acid, or, in other words, the contents of the tubuli 
are distinguishable into a homogeneous cortical substance and 
a finely granular colourless axial substance ; in other muscular 
tubuli again, as for instance in those of the pharynx and of 
the heart, the minutely granular axial substance becomes 
farther developed so that the granules acquire sharper outlines, 
and what should be specially noted, are so disposed that mus- 
cular tubulus of this kind, as in the heart of Paludina, is 
so much the more like an immature, transversely-striped 
primitive muscular fasciculus of a higher animal, as the 
granules in the tubulus may be more numerous. 

’ In this way might a parallel be drawn between the primi- 
tive muscular tubuli of the Mollusca and the striped primitive 
muscular fibrille of the Orthropoda and Vertebrata; their 
inferiority consisting only in this, that their contents are not 
developed into fibres as they are in the latter. A very faint 
longitudinal marking is evident in many, especially of 
the compressed muscular tubuli of Paludina vivipara, for 
instance in the foot, which disappears under acetic acid, and 
of which it is doubtful whether it is situated in the membrane 
or in the contents of the tubulus. 

No muscles corresponding to the smooth muscles of the 
higher animals exist in Paludina vivipara; that is to say, no 
muscular fibres representing a single elongated nucle: ited cell. 
All their muscles are tubuli, and are produced by the coa- 
lescence of a series of cells. 


38 MEISSNER ON A FUNGOID GROWTH IN THE NAILS. 


On a Funcow Growrn in the Naits. By C. Meissner. 
Abstracted from the ‘ Archiv f. Physiol. Heilkunde,’ Jahrg. 
i leap 3193; Pi. 1: 


Tue numerous observations which have been made respecting 
the growth of Fungi in and upon the human body, both in the 
mucous membranes and on the skin, may be divided into very 
distinct classes,. having reference respectively to the real sig- 
nificance, in a pathological point of view, of the fungoid 
growths. In the one case the production of the lowest vege- 
table organisms may be wholly and merely accidental, and be 
connected with the co-existing pathological processes only in 
so far as the latter may afford the conditions, or the appro- 
priate soil for their vegetation. In the other set of cases, 
which are very much more infrequent, these morbid changes 
of the organs are more intimately connected with the fungoid 
growth ; so that, in fact, the Fungus is, to a certain extent, the 
disease itself. The number of affections referable to this 
category—so far as they are as yet known—is very small; for, 
perhaps, the fungus of Porrigo lupinosa (favus), and that of 
Pityriasis versicolor, are the only ones which can be included 
in it. The fungoid growth which occurs in aphtha must 
probably remain doubtful and improbable. 

In the course of the summer (1852) the author had an 
opportunity, in the Clinic of Professor Baum, of observing a 
species of fungoid vegetation, of which no mention, according 
to him, had previously been made, and which would pro- 
bably belong to the second class of cases above mentioned. 
The subject of the observation was an old man of 80, who 
had been admitted into the hospital for a tumour of the ¢est¢zs. 

The finger-nails presented an extraordinary appearance, 
and abnormal form. ‘They were about 1-12th of an inch 
thick, nearly throughout, and at the same time much arched 
above, so that the anterior portion was incuryed like a claw 
over the point of the finger: the anterior edge was thick and 
broad, but presented in no respect the conformation of the 
nails which is usual in phthisis and cyanosis. Their colour 
was, for the greater part, a peculiar yellowish-white, in places 
passing into brownish, and quite opaque; but this abnormal 
and very remarkable discoloration was not uniformly spread 
over the whole nail, frequently forming merely streaks running 
from the root of the nail as far as the free border, and between 
them were spaces more or less numerous in different nails, 
which, except in the abnormal thickness, appeared sound, 
red, and transparent. The nails, moreover, were more move- 
able in their bed than is natural; they were not, however, 


Pe 


MEISSNER ON A FUNGOID GROWTH IN THE NAILS. 39 


although in a state apparently of dying off, full of cracks 
and pert, but, on the contrary, were hard aul brittle under 
the aula: like wood, All the nails were thus affected, except 
that of the right index-finger, which was quite sound. 

The author’s attention having been directed to the subject 
by Professor Baum, he examined a piece of the nail, in order 
to ascertain whether any air was contained between its cells, 
upon which the abnormal appearance might depend. Ona 
longitudinal section the surface exhibited streaks, which ran 
from behind forwards, and were frequently of a yellow or 
brown colour; and while the surface of the nail, as above 
said, was smooth internally, it appeared disintegrated, easily 
separating into thin lamelle, all of which were quite opaque. 
One of these lamella, treated with caustic soda, and examined 
microscopically, was composed of the well-known cells of 
which the nail is constituted; but, as these were rendered 
transparent, and swollen under the influence of the re-agent, 
there was apparent a rich plexus of variously convoluted fila- 
mentary fungi, which spread upon and between the cells, and 
frequently projected beyond the free edge of the object. All 
the affected nails presented the same appearances. The fungus 
is very similar to that of Porrigo lupinosa, and Pityriasis versi- 
color. ‘The author noticed a mycelium, composed of long, 
much branched, jointed filaments. They appeared greenish 
from the diffraction of the light; had a width of 1-900th— 
1-700’"th, many even only of 1-1000’’th, and consisted of 
succesSive joints, which were not of uniform size, though, on 
the average, from two to four times as long as broad, but were 
frequently also scarcely perceptible. This growth, in many 
places, formed a very thick felt, which was very beautifully 
seen when the cells of the nail were almost dissolved under 
the prolonged action of the soda, by which the fungus was in 
no way altered. Besides these, there occurred broader, shorter, 
unbranched filaments, of a clavate form, which were much 
more distinctly jointed, and consisted of short, square, or 
rounded segments ; these were the sporangia, containing the 
spores disposed circularly, and consequently having a double 
outline, the outermost delicate line being that of the sacculus 
itself, the inner that of the spores. Imbedded in the network 
formed by these filaments, and those of the mycelium, there 
were, lastly, large masses of free, detached spores in vast 
quantities. The latter were round, also of a greenish hue, and 
of very various sizes ; the smallest measuring only 1-1000’’th, 
up to 1-900’’th ; the largest as much as 1-450’’th. 

The fungus above described differs from that of Pityriasis 
versicolor in the jointed structure of its mycelium, and the 


40 MEISSNER ON A FUNGOID GROWTH IN THE NAILS. 


greater size of its filaments and spores. It has the greatest 
general resemblance to the fungus of Porrigo lupinosa ( favus) ; 
the mycelium of the latter, however, is also unjointed, and the 
author states that he did not find the spores so large as in the 
ungual fungus. 

The disposition of the growth in the substance of the nail 
could be very well observed in vertical sections. In thin 
sections made in this direction, treated with soda, it was evi- 
dent that the fungus extended through the entire thickness of 
the nail, forming strata, running in streaks from the root of 
teal for wards, and parallel with the surface. The cells of 
the nail were separated from each other by the fungoid strata, 
and the thickening of the nail was perhaps exclusively owing 
to them. The above described yellow and brownish lamellee 
and streaks were seen to be due to the fungus, consisting, in 
fact, almost entirely of masses of innumerable spores. The 
peculiar discoloration of the nail was produced by them, 
just as the brown colour of scales in Pityriasis versicolor is 
ascribable to the fungus. 

The toe-nails were thickened, fissured, and whitish, as is 
usual in old people, but presented no trace of the fungoid 
growth ; nor did any part of the skin, which was dry and scurfy. 

When asked respecting his nails, and the cause of their 
alteration, the old man stated, that about thirty years pre- 
viously, a heavy weight had fallen upon his fingers, in con- 
sequence of which, the nails were broken and had comé off ; 
that they subsequently grew again, but had gradually heibine 
thick and white ; he did not remember whether the right fore- 
finger had escaped at the time of the accident or not. 


On the Multiplication of Chara by Division. By M. C. 
Montacne. Comptes-Rendus, Tome xxxiv., No. 24, 


p. 898. 


Tue object of this Memoir is to demonstrate what had pre- 
viously been merely suspected, viz., that certain species of 
Chara, but especially Chara stelligera, Bauer, were capable 
of propagation in another way than by spores, that is to say 
by bulbillr, a mode of reproduction analogous to what takes 
place in several of the Liliacew, and many other plants, both 
vascular and cellular. 

The multiplication of this species, which is rarely and 
widely distributed, and which very seldom indeed produces 
spores, is insured by the mode above adverted to. The 
author proceeds to describe the bulbules in the following 
manner :— 


MONTAGNE ON THE MULTIPLICATION OF CHARA. 41 


“The apparatus in question is formed by the agglomeration of cells, 
developed in a circular manner around the principal tube, on a level with 
the septa, or endophragms. ‘These cells, disposed like the sides of a melon 
or gourd, spring from the wall itself of the tube, according to the laws of 
the multiplication of vegetable cells, observed by MM. Mirbel and Hugo 
Mohl, confirmed by the more recent observations of others, and among 
them of M. W. P. Schimper, who, in a Paper on ‘ Red Snow,’ gives to 
this mode of multiplication the very suitable name of ‘ exogenous cell 
formation.’ The cells which constitute the star-like nodules multiply in 
two different ways: the division takes place either in an excentric manner, 
and on the same plane, in which case the stellate concretions are produced, 
to which the plant is indebted for its specific name,—or the division is 
effected in a direction parallel to the axis of the central tube, and in this 
case sometimes as many as four rows or whorls of super-imposed cells may 
be counted, but no rays. The number and arrangement of the cells in 
these bulbules is best made out in sections of them, to which has been 
added a drop of solution of iodine, which colouring blue the grains of 
starch, and not so affecting the tissue of the dissepiments, renders the cells 
in question evident, and allows of their being counted. When mature 
they are filled with starch, whence they acquire an ivory-white colour 
and polished surface. In the younger state the cells are green, and con- 
tain no starch. The interior of the starch-bearing cells is occupied by a 
reticulated cellular tissue in the utricles of which the starch is generated.” 

Bulbules of a similar kind, but of different aspect in the 
different species, have been observed in C. hispida, C. aspera, 


C. alopecuroidea var. Montagnei. 


On Sarcina in the Lunes.—Zeitsch. f. rat. Medizin, von Dr. 
J. Henle, and Dr, C. Pfeufer. 


Dr. Zenker, of Dresden, found Sarcina in the lungs of the 
body of a female aged 38, dead of medullary cancer, This 
was the second occasion on which this production had been 
found in those organs. The first case was observed by Vir- 
chow, but it would seem that the more recent instance noticed 
by Dr. Zenker differed from the former in many material 
respects. 

The following account is extracted from the history of the 
post-mortem examination. Both lungs were free, with the ex- 
ception of a loose adhesion at the inferior border of the right ; 
everywhere highly emphysematous, not collapsing, and pale. 
In both lungs there were scattered through all the lobes a 
moderate number of whitish-grey, or greyish-red medullary 
tubera, varying in size from that of a pin’s-head to that of a 
hazel-nut, of a rounded form, placed on the surface, and some- 
what projecting above it, soft and readily enucleated, leaving 
a smooth surface. The superior lobes of both lungs every- 
where contained air, and were in various spots more or less 
cedematous. The inferior lobes were, for the most part, also 


42 ON SARCINA IN THE LUNGS. 


filled with air, very oedematous, and, towards the base, rather 
friable ; their posterior surface, to some extent, of a uniform, 
dark blue colour; the tissue bordering this surface (on the 
right to a greater depth than on the left) without air, of a dark 
grey red colour when cut, and on pressure affording an abun- 
dant, serous fluid. 

In each lower lobe, both in the parts containing and in those 
without air, were presented, on a section being made, numer- 
ous, distinctly yellow coloured, ill-defined spots. When the 
substance of the lung was squeezed, in these spots, a few 
minute yellow flocculent particles were obtained mixed with 
the Sarcina, and which, from their colour, which the author 
believed must have been derived from altered hematin, at- 
tracted his attention. Upon his subjecting them to micro- 
scopical examination, he found, to his astonishment, both in 
the flocculent particles, as well as in their neighbourhood, 
tolerably numerous specimens of the Sarcina in the most dis- 
tinct forms. 

They showed division up to the third stage (64 squares), 
were in part quite colourless, in part of a light yellowish colour 
or greenish, and with respect to their figure differed in no 
way from the well-known forms. Upon further investigation, 
the Sarcina was found not only in all the above-mentioned 
yellow spots, but also, in greater or less numbers, in the serous 
fluid, expressed from other parts of the lungs which did not 
present the yellow spots and floceull, 

The author concludes, that the Sarcina in this case was not 
primarily developed in the lungs, but rather that it had 
reached them from the stomach. (It may be observed, that 
in the stomach also, there was found a great abundance of 
Sarcina.) The author thinks, that some of the contents of the 
stomach during life had been brought up by eructation, and 
had got into the air-passages from the pharynx. 

‘With reference to the above, Heller (Archiv f. phys. u. 
path. Chemie u. Mikrosk. H. 5, 1853, p. 197) remarks, that 
he assigns no importance to the occurrence of the Sarcina in 
parts beginning to putrify and consequently in dead bodies, 
because the Sarcina, like other fungi, may not have been 
formed in them till after death—an opimion which he attempts 
to confirm by his observations on luminous dead fish, marine 
animals, sausages, &c.—(Heller’s Archiv, 1. c.). 

(This opinion of Heller’s, however, is obviously quite in- 
admissible, as there is not the most remote connexion between 
the organism in question, and any known form of fungus oc- 
curring in dead animal or vegetable tissues.) 


SHORT NOTICES. 43 


Contributions to the Knowledge of the Hairs of ‘Collomia coccinea’ 
by Dr. Ovupemans (Botanisch Zeit., Part 24, June 17, 
1853), with a plate. 


Tue author describes two kinds of hairs:—one conical 
and pedunculate, consisting of 2 or 3 cells, and with toler- 
ably thick walls ; these cover particularly the under surface 
of the leaves ; and a second, capitate (glandular hairs as they 
are termed), with which the sepals more especially are clothed, 
but which are also found upon the upper surface of the leaves. 
His observations were devoted more particularly to the latter 
form of hair, and he states that they are distinguished by the 
following characters :— 

1. Their compound structure. 

2. By the presence of a distinct cuticula, which invests the 
whole hair. 

3. By the cells containing green matter, belonging to the 
capitulum. 


History of the Development of the Flower and Fruit of ‘ Man- 
glesia cuneata’ Endl., by Dr. HERMAN Scuacut (Botan. Zeit., 
June 24, 1853), with a plate. 


Contributions to the Knowledge of the Nostachacee, and an 
attempt at their natural arrangement. Inaugural dissertation, 
by Dr. L. Fiscuer, Dr. Phil. Bern, Hulier & Co. 1853. 
pp. 24. 4to, with 1 lithographic plate. 


On the Cuticle of Ligneous Plants, by Dr. Tu. Harrie. 
(Botan. Zeit., June™3, 1853). 


Tue author says— 

1. That a simple cuticle, which is to be regarded as a distinct 
organ, exists as the most external investment of the plant, of 
which it constitutes the outermost closed boundary, whence 
to a certain extent it is the primordial cell of the individual, 
from the first appearance of the embryo until it is destroyed, 
and on older parts of the plant, is replaced by cork-tissue. 

2. That in most plants, between the cuticle and epidermis- 
cells, a substance is deposited in larger deposit-layers, which 
differs from the cuticle as well as from the epidermic cells by 
its solubility in caustic potass; and which, at least in all 
cases, cannot arise from a transformation of the outer cell- 
walls, since if is also apparent upon such epidermic cells, as 
have their walls thickened either not at all, or uniformly 
throughout, as, for example, in Ruscus and Salisburta, or as 


44 ; SHORT NOTICES. 


in the leaf of the Conifera, between the epidermic cells re- 
sembling bast- fibres and the cuticle. 

3. That the epidermis is also closed over the stomates. 

He then proceeds to describe the mode iu which his investi- 
gations were made. 


De plantarum generatione sexuali Dissertatio inauguralis phy- 
siologica, by Dr. Anton DE Bary. Berlin, 1853. pp. 30. 


8vo. 


Tus essay affords a complete review of all the discoveries 
and opinions respecting the sexuality of plants, having refer- 
ence to the actual process of impregnation in the vegetable 
kingdom, from Kélreuter to the present time. 


= 


In the ‘Bulletin Scientifique’ of the September number of 
the ‘ Bibliothek. univ. de Geneve,’ is contained, in the botan- 
ical section, a list of various observations respecting the dis- 
ease of the vines in the year 1851. And besides the papers 
by Professor Mohl enumerated in this list are the following 
Essays, for the most part in the Transactions of Societies :— 


Lettre de M.-le Dr. Desmoulins, au Congrés scient. d Orléans 
sur la Maladie des Raisins. Orleans, 1851, 


Lettre de M. le Dr. Leén Dufour a M. le Président de la 
Soc. Lin. de Bordeaux relativement a la Maladie des Raisins. 


18 April, 1852, in the Act. Soc. Linn, Bord., v. 17, liv. 1. 


Ch. Laterrade, Maladie du Raisin, et de la Pomme de Terre, en 
Suisse, en 1851. In the Actes de Acad. de Bordeaux. 


R. Blanchet, la Maladie du Vigne dans le Canton de Vaud en 
1851. In the Bull. de la Soc. Vaudoise des Sc. Nat. 


The ‘conclusion which may be deduced from these observa- 
tions is the following:—1l. The Oidiuwm Tuckheri is the true, 
principal, and extrinsic cause of the disease. 2. This disease 
is probably not new in Europe, but has not hitherto been so 
general or so active. 3. It is not proved that the same Oidium 
occurs on other plants. 4. When insects are found upon the 
diseased vines, either internally or externally, they constitute 
only a local and accidental phenomenon, and may induce either 
an aggravation or a diminution of the disease. 


"aon a 


( 45 ) 


REVIEWS. 


Tue Microscope IN ITs Spectran APPLICATION TO VEGETABLE ANATOMY 
AND Puysiotogy. By Dr. Hermann Scuacut. Translated by Frr- 
pERIcK Currey, Esq., M.A. Withnumerous Illustrations. Highley’s 
Library of Science and Art, London. 


In the first number of the ‘ Microscopical Journal’ we called 
attention to this little work of Dr. Schacht’s on the Microscope, 
and we are glad now to be able to introduce it to our readers 
in an English dress. We stated ouropinions of the work so 
much at length in our first notice, that we must now confine 
ourselves to the translation. Mr. Currey has, we find, omitted 
most of the remarks made by Dr. Schacht on foreign micro- 
scopes, which would have been of but little advantage to the 
English reader. We would here repeat what we have often 
before stated, that the best foreign microscopes are inferior to 
those of our three great firms, and that the English student 
can derive no advantage from the purchase of the former. It 
is true our best microscopes are expensive, but we are glad 
to find that efforts are being made to place in the hands of 
the English student instruments which, while they are as 
convenient in their construction and cheap as foreign ones, 
will possess the excellent glasses of English makers. 

Dr. Schacht’s remarks on the use of the microscope are 
chiefly illustrated by reference to the vegetable kingdom, but the 
general principles on which the instrument must be employed 
are the same in every department of nature. At the same 
time the botanical student will especially find in this work a 
number of admirable remarks on the structure and nature of 
vegetable tissues. As an illustration we give the following 
account of the development of the flowers in Cleome arborea :— 


“‘ The first rudiments of the flower appear, in the usual manner, in the 
form of a cellular cone in the axil of the bract; shortly afterwards appear 
the rudiments of the four sepals, and next to these come the four petals 
alternating with the sepals, Figs. 40 and 41 represent a flower in a 
young state seen from above. After this, however, follows a whorl of six 
elements. Fig, 42 shows a flower at a somewhat later stage than is 
represented at fig. 41. In fig. 42 the sepals are removed, and only two of 
the petals drawn. Fig. 43 represents a very perfect transverse section, 
showing all the parts of the flower. It might, perhaps, be supposed that 
there were two whorls of anthers, each whorl containing four elements, 
and that two of the elements of these whorls were abortive; but that 


46 SCHACHT ON THE MICROSCOPE. 


this cannot be so is shown by the regular position of the six anthers in 
one whorl, which always occurs in good specimens. The long-stalked 
ovary, which is subsequently developed, appears in the form of a solid 
column; at its apex there is formed a small depression which at first is 
very flat; the depression subsequently increases, and the ovary assumes 
the form of a cup. The edge of this cup afterwards increases in thickness, 
its walls approximate to one another, and form the stigmas and the style. 
The ovary is unilocular with two parietal placenta. The ovule has two 
integuments ; at a later period it exhibits a peculiar curvature ; the anther 
is quadrilocular, but at the time of dehiscing it is bilocular. 

“ Rio, 44 represents a longitudinal section corresponding to the stage of 
development, represented at fig. 43. Figs. 45 and 46 represent longi- 
tudinal sections of the ovary in different stages of development, the sepals 


Fig. 44. 


i | x40 
R 


and petals being removed; (x) is the hollow of the ovary. Figs. 47 and 
48 represent transverse sections of the ovary in different stages of develop- 
ment. Fig. 49 represents a transverse section of the young anther; it is 
quadrilocular ; (@) is the vascular bundle of the connective, (b) one of 


Bee. es 


spernuoph he 


SCHACHT ON THE MICROSCOPE. AZ 


the chambers of the anther, (c) the cellular tissue of the connective, 
which is absorbed shortly before the dehiscence of the anther.”—p. 111, 
112, 


The drawings, which in the original were on separate plates, 
are here introduced into the text in the form of woodcuts. 
The work is neatly got up, and sold at a low price, and forms 
one of a series of works forming a library of science and art, 


published by Mr. Highley, of Fleet-street. 


A Naturauist’s RaMBLeS ON THE DEVONSHIRE Coast. By Pup 
Henry GosskE, A.L.S., &c. London, Van Voorst. 


Every naturalist should possess a microscope: in fact it is 
becoming every day more obvious that a man cannot be a 
naturalist without one. At any rate, those naturalists who 
wish for a notice in our pages must use the microscope or we 
shall be compelled to pass them over. Mr. Gosse had a true 
eye to the all-embracing nature of the study of natural history, 
when, in reply to the question of where he should go for the 
benefit of his health, ‘‘ Now where shall it be ? Leamington— 
Tonbridge Wells—Clifton? No, none of these; since I 
must go, it shall be to the sea-shore ; I shall take my micro- 
scope with me ; and get among the shells and nudibranchs, the 
sea-anemones, and the corallines.” And we will stake our 
medical reputation upon the success of such occupation in 
such districts in hundreds of cases like Mr. Gosse’s, where 
blue pill, hydrocyanic acid, and the most approved dietetical 
regimen have utterly failed. What can be more healthful 
than the exercise of body and mind in the fresh air of the 
sea-side, whilst seeking for the animal and vegetable treasures 
on the shore or in the waters of the ocean ? 

But let us follow Mr. Gosse to the sea-shore. He went to 
Devonshire, and was not long before his microscope was un- 
packed ; and, as it is impossible for us to describe all that he 
has recorded of what he saw under the microscope, we must 
content ourselves with giving a few extracts, as indicative of 
the pleasant things to be met with in his very pleasant 
volume. He has caught a pecten, and of course kept it alive 
_ for some days ina marine aquavivarium, by which term is 
to be understood a hand-basin of sea-water; but his pecten, 
as pectens and other sea creatures will do, dies :— 

*« The death of my little pecten gave me the opportunity of submitting 
some of the gemmeous specks to the microscope. With a power of 220 
diameters, I distinctly perceived a large lens, a glassy coat investing this, 
which itself was buried for more than half its volume in an investiture 
apparently granular, of a yellowish brown colour, having an ill-defined 


48 GOSSE—RAMBLES ON THE DEVONSHIRE COAST. 


circle near its anterior side, of a blackish hue. Under pressure with the 
compressorium, the lens was manifestly circular; the coloured socket 
discharged dark granules, and from the darkest part a deep crimson pig- 
ment, which did not appear to be granular, 

“ T submitted portions of the gills also to the same magnifying power. 
Each of the four lamine consists of a vast number of straight slender 
transparent filaments, evidently tubular, and about 1-1500th of an inch in 
diameter, arranged side by side; or rather of one filament, excessively 
long, reverted upon itself again and again, at both the free and the attached 
end of the lamine, throughout its whole extent. This repeated filament 
is armed on each of tavo opposite sides with a line of vibrating cilia, the 
two lines moving in contrary directions ; by the action of which a current 
of water is made continually to flow up and down each of these delicate 
filaments : so that the blood which circulates in their interior (for they are 
doubtless blood-vessels) is continually exposed throughout this its long 
and tortuous course to the action of oxygen. 

“¢ Like all organic functions, the action of these cilia is not under the 
will of the animal. It is said that if, during life, a small portion of the 
gills be cut off, the motion of the cilia will convey the fragment swiftly 
away, with a smooth easy motion, through the surrounding fluid, in a 
definite direction. It does not cease even with the life of the animal. 
The specimen which I examined had been dead at least fifteen hours, yet 
when I placed the torn fragments of the branchie, one after another, 
beneath the microscope, the energy of the ciliary action, as the wave 
flowed with uniform regularity up one side and down the other of every 
filament, filled me with astonishment. Even the next morning, twenty-six 
hours after death, when the tissues of the filaments were partially dis- 
solved, the ciliary motion was still going on, on portions that preserved 
their integrity.” —p. 52-54, 


The capture of a madrepore affords our naturalist an oppor- 
tunity of examining its structure under the microscope. 
Nothing is more marvellous to the observer of the tissues of 
these animals for the first time than the filiferous capsules or 
thread-cells with which many of these creatures abound. In 
the madrepore certain salmon-coloured bands are observed, 
sometimes regarded as ovaries :— 


«¢« Having detached a minute portion of one of the bands, I submitted it 
to an uniformly graduated pressure on the stage of the microscope, when 
I found that in its substance were imbedded a great number of filiferous 
capsules, exactly resembling, in essential points, those of certain Medusz. 

“The capsules are transparent and colourless, in shape a long oval 
from 1-650th to 1-800th inch in length, and are seen to contain a thread 
closely coiled. When the pressure reaches a certain point, the capsule 
shoots forth from one end the elastic thread, which in a moment starts 
out like a spring to a length thirty times as great as that of the capsule: 
sometimes in a straight line, sometimes in a serpentine, or (as I rather 
believe) a spiral form. The capsules do not bwrst, yet, at the instant of 
the propulsion of their filament, there is a distinct crack heard. 

** I now cut off carefully, with fine-pointed scissors, two or three tenta- 
cles from one fully expanded, and submitted them to the same scrutiny. 
The rounded head of the tentacle appeared rather rough or hairy at first, 
but, as pressure began to flatten it, filiferous capsules were seen to be 
protruding from the outline, which increased in number as the pressure 
proceeded, until an amazing multitude appeared, and the whole substance 


GOSSE—RAMBLES ON THE DEVONSHIRE COAST. 49 


of the tentacle-head was seen to be literally composed of these capsules, 
as thick as spicule in any sponge, with only a slight quantity of gelati- 
nous matter to hold them together. To see these thousands of little 
vesicles discharging their missiles in rapid succession, like the flights of 
arrows in ancient battles, was an astonishing sight. When the propulsion 
could be distinctly followed by the eye, there was always seen a little 
zigzag line on each side of the thread, reaching to a considerable distance 
from the base, which I at first thought indicated a delicate membrane 
pushed out from the orifice of the capsule by the projected thread, until 
it at length burst, and shrank back in folds around the base. The form 
of the capsules differed from that of those described above, in that they 
were proportionally longer and more slender, being in fact almost linear. 
I could not discover any capsules in the body of the tentacle, but only iz 
the head. 

** If, indeed, these projected bristles are so many darts injected into the 
bodies of those minute animals which are the prey of the Madrepore, 
accompanied, as we must suppose each puncture to be, to insure its effect, 
with a fatal poison,—does not their presence in the convoluted bands of 
the interior militate against the supposition that these bands are ovaries, 
especially as I have seen the curious manner in which these are appressed 
to the swallowed morsel? Is it unreasonable to conjecture that their 
office may be accessory to that of the tentacles, destroying what may 
remain of life in the victim, after it has been enclosed by the lips, and is 
consequently out of the reach of the tentacles ? 

“ This inference was confirmed by the results of further investigation ; 
for, examining in the same manner other minute portions of the frilled 
bands, as I could detach them with the point of a pin, I at length found 
a piece in which the capsules were much more numerous, and vastly 
larger than any that I had yet seen, whether in the bands or the tentacle- 
heads. They were fully 1-300th inch in length, long-oval, but somewhat 
curved. Their size enabled me, with a power of 300 diameters, to see 
their structure much more distinctly. 

*« At the larger end is situated a lozenge-shaped body reaching to the 
middle ; from the inner end of this, partly coiled round it, but extending 
through the remainder of the capsule, is the thread, lying in an irregular, 
rather loose spiral, the appearance of which differs considerably in different 
capsules. When it is projected, the whole contents of the capsule disappear 
from the interior, in a manner which induces me to believe, strange as it 

seems, that the lozenge-shaped body at least, if not the whole thread, is 
turned completely inside-out; for the extended thread is attached, not to 
the smaller, but to the larger end, without the least appearance of rupture. 

“Now for the structure of the thread, or wire, for it is as elastic as 
steel. This is marvellously elaborate, especially when we consider its 
excessive tenuity, the threads of the largest capsules being less than 
1-7000th of an inch in diameter, and those of the smallest perhaps 
1-20000th of an inch. The basal part of the thread, to a length about 
half as great again as that of the capsule, is clothed with alternate series 
of triangular plates, laid one over the other, or imbricated, like the scales 
of an artichoke. About half of this portion is furnished with an armature 
of hairs rather closely set, standing out at right angles, like a bottle-brush ; 
they are twice or thrice as long as the diameter of the thread, in the 
middle of the brush, but diminish to each end; the individual hairs 
taper to a point. 

‘| have offered a conjecture that the projection of the thread is an evolu- 
tion of its interior, and I believe that it is a complete one through its 
whole length. I have, even since I wrote that conjecture, seen an ex- 

VOL, Il. E 


50 GOSSE—RAMBLES ON THE DEVONSHIRE COAST. 


ample of the process, which I can scarcely describe intelligibly by words, 
but the witnessing of which left on my own mind scarcely a doubt of the 
fact. It was effected not with the flash-like rapidity common to the pro- 
pulsion, but sufficiently slowly to be watched, and by fits or jerks, as if 
hindered by the tip of the lengthening thread being in contact with the 
glass. In consequence, probably, of this impediment, it took a serpentine, 
not a straight form, and each bend of the course was made and stereotyped 
(so to speak) in succession, while the tip went on lengthening ; and the 
appearance of this lengthening tip was exactly like that of a glove-finger 
turning itself inside out. 

“‘ The brush of hairs, I think, is originally enclosed in the lozenge at the 
large end of the capsule. Both the lozenge and the brush are wanting in 
the small filiferous capsules ; when I observed them in the large ones, the 
suggestion occurred that I might have overlooked them in the smaller, on 
which I examined some afresh with the utmost care, but in each case, the 
thread, which at first occupied the whole cavity of the capsule without any 
lozenge, was simple when evolved. 

«‘ The capsules appear confined to the thickened edge of the frilled band, 
in which they are set side by side, pointing outwards.”—122-126. 

We had marked many other passages, but the length of our 
last extract precludes further quotation at present. We may 
draw on Mr. Gosse’s pages at a future opportunity. Now all 
we have left ourselves to do, is to commend Mr. Gosse’s 
volume to the attention of our readers. It is not alone those 
who are about to visit the Devonshire coast that will find it 
of interest, but all who are fond of nature and natural scenery 
as they present themselves by the sea-shore. ‘The volume is 
illustrated by twenty-eight plates, most of which are coloured, 
affording livély illustrations of the objects*observed. Many of 
these contain representations of the microscopic structure of 
the higher animals, and not a few are devoted to microscopic 
objects alone. 


—_—---. * 


sii a 


NOTES AND CORRESPONDENCE. 


@n the best Form of Micrometer for the Microscope.— Now 
that the achromatic microscope is an instrument found in the 
hands of so many persons, and investigations are carried on 
generally with such extreme accuracy, it has become abso- 
lutely necessary that a mode of micrometrical measurement 
should be universally adopted, which, while it admits of easy 
application, shall at the same time be capable of as extreme 
minuteness and accuracy as modern art can achieve. | am 
afraid it cannot yet be said that this is the case, inasmuch as 
not one person, perhaps, in ten uses the cobweb micrometer, 
which, in my opinion, as far exceeds in point of exactness 
the common eye-piece apparatus as the modern achromatic 
microscope surpasses the old-fashioned instrument. It is a 
matter of astonishment to me to find two such acute and accu- 
rate observers as Mr. Jackson and Mr. Quekett advocating the 
use of the slip of ruled glass in the eye-piece, and disparaging 
the cobweb micrometer on such fallacious grounds as the follow- 
ing: viz. that as the value of the divisions in each apparatus 
must be calculated by the ruled lines placed on the stage and 
based on their supposed correctness, therefore the one form 
must be as correct, or nearly so, as the other. 

The object of this short paper is to point out this fallacy, 
and to prove, at the same time, if indeed it needs proof, first, . 
that the cobweb micrometer is, at the least, equally easy to 
use as its rival; secondly, that the measurements made with 
it far exceed those made with the latter in point of accuracy. 

In the first place no one will deny that the one form of 
instrument is as readily placed zn position for measurement as 
the other; if so, any advantage in point of facility in use that 
the one may have over the other must be in reading the divi- 
sions ; and I appeal with confidence to any impartial person 
whether (setting aside the superior ease with which the cob- 
web lines give the exact diameter of the object) the notches 
of the comb and the divisions of the milled head are not as 
easily read off and referred to the table of values as the lines 
on the ruled glass plate. I[ think I may at once assume that, 
as far as regards manipulation, one form of micrometer is just 
as simple as the other. 

Now, with regard to the second point in question, let us 
see whether the two forms are also equal in point of accuracy, 


E 2 


52 MEMORANDA. 


In every glass plate, which has been ruled with lines either 
1-100th, or 1-500, or 1-1000th of an inch apart, there will be 
discovered, upon close examination, some inequality in the 
spaces. I at least have never yet seen one in which I could 
not detect an error, while in many it has been very consider- 
able. Now an error to the amount of 1-1000th of an inch is 
easily made, and easily passed over by the observer; and if 
he uses such a plate in his eye-piece as a micrometer, many of 
his measurements will be affected by that error; while some 
again may not, owing to the use of a different portion of the 
ruled space; and thus an inequality or irregularity will run 
through his recorded measurements. This source of error 
cannot be avoided except by taking a number of measure- 
ments of the same object on different lines, and then striking a 
mean of the whole. Who is there, I may ask, who ever has 
or ever would take this trouble? 

With respect to the cobweb micrometer the case is differ- 
ent; here there can be no possible error arising from the 
micrometer eye-piece itself, provided it is as good in point of 
workmanship as those of Messrs. Powell and Lealand. The 
only source of error lies in the stage micrometer used to deter- 
mine the value of its divisions ; and the’ mode of obviating this 
is sure and perfectly simple. My plan has been to procure three 
ruled slips of glass, ruled to 1-500th, 1-1000th, and 1-5000th 
of an inch respectively. I first take a mean of the values of 
the divisions in the eye-piece, observed on three different por- 
tions of the ruled space in each one of the three ruled slips; 
this gives me three values, or one for each slip; then a mean 
of these three will, I conceive, approach as near to absolute 
correctness as any one could wish to attain. 

The value, then, of the divisions in the cobweb micrometer 
(which should be drawn out in a table for reference) will be a 
mean of nine observations with each object-glass. And when 
once this table has been drawn up I need scarcely say that 
every single measurement that may be made hereafter must 
be correct, without the necessity of any further trouble; or, if 
there be an error, it rests with the observer, and not in any 
part of the instrument he uses. 

It is obvious to remark that in order to arrive at equally 
accurate measurements with the common positive or negative 
eye-piece micrometer (even granting that such could be made 
at all, which I dispute) at least nine different measurements 
must be taken of every object measured, and three different 
slips of glass used for the purpose. 

In respect to minuteness of measurement of course the cob- 
web micrometer carries off the palm; here the eye-piece ap- 


MEMORANDA. 53 


paratus cannot attempt to compete with its rival. Mr. Jack- 
son has stated that a space so small in amount as 1-800,000th 
of an inch may be appreciated with the former instrument 
when used with a 1-8th object-glass. I find, however, that 
the value of each division of the milled head with that object- 
glass is 1-300,000th of an inch, and that, in practice, a turn of 
the screw less than four of these divisions is not appreciable 
by the eye; giving, therefore, 1-75,000 of an inch as the 
smallest measurable space with the 1-8th, and 1-112,000th 
with the 1-12th object-glass. Whatever may be Mr. Ross’s 
opinion, I do not hesitate to say that it is quite possible with 
a modern 1-12th object-glass and a good cobweb micrometer 
to estimate a quantity as small as the 1-100,000th of an inch 
with ease and precision. 

Mr. Jackson is of opinion (‘ Trans. Microsc. Soc.,’ vol. ii. 
p- 136) that, although so accurate a measuring instrument as 
the cobweb micrometer may be necessary in the case of the 
telescope, yet it is not so with the microscope, alleging, as a 
reason, the advantage the former instrument possesses in 
having the uniformity of time for a basis of measurement. I 
think, however, that I have shown that the value of the divi- 
sions in this micrometer, when applied to the microscope, 
may be easily ascertained to such a nicety that the amount of 
error is reduced to very small dimensions indeed, so much so, 
as to be quite inappreciable, if it be not entirely destroyed ; 
and if this be so, then I cannot see why a more accurate 
means of measurement should be applied to the telescope 
(when the magnifying power with such observations rarely 
exceeds 500 times) than to the achromatic microscope, whose 
definition is infinitely superior to that of the former instru- 
ment, and whose magnifying power, with the micrometer, 
amounts often to 900 diameter, and occasionally to as much as 
1200. 

It is said that the measurements of the cobweb micrometer are 
unnecessarily fine, and that the expense of the instrument must 
prevent its ever coming into general use. This doctrine I 
confess I cannot understand. I can conceive no measurements 
to be too accurate; nor do I think that the difference between 
47. and 1/7. would be any obstacle to the more extended use of 
the more expensive instrument, provided its superior qualities 
were thoroughly known and appreciated. 

The names of Mr. Jackson and Mr. Quekett, both of them 
noted microscopists and accurate thinkers, must of necessity 
carry great weight, and will, I fear, have induced many per- 
sons to adopt that form of micrometer which is most econo- 
mical in point of expense, though, as I think I have shown, 


54 MEMORANDA. 


least accurate in practice; and it is with the view of counter- 
acting what I believe to be a fallacy in their writings, and with 
the desire that the greatest possible accuracy should attend 
everything connected with our favourite instrument, that I 
have been led to make these few remarks.— H. C. K., Stretton 
Rectory, near Hereford, July 16, 1853. 

On Rotation in the Cells of Plants.—Last summer I as- 
certained the occurrence of this rotation in a very distinct 
form, in a plant recently added to the British flora—Anacha- 
ris Alsinastrum. This is an aquatic plant, the new “ water 
weed,” as it is called, which has recently appeared in great 
abundance in the rivers and streams of various parts of Eng- 
land, so much so as to interfere with navigation and fishing, 
and especially to put a stop to regattas and sailing matches,— 
it has completely blocked up some of the canals and locks of 
the English fens. It is supposed by some botanists (and with 
very good reason) that the Anacharis has been accidentally in- 
troduced with timber or other material from North America, 
where a species ( Udora canadensis), apparently identical, is of 
common occurrence in the rivers. As elsewhere, this plant 
has made its mysterious appearance in the pond of the Edin- 
burgh Botanic Garden, where it is not known to have been 
planted. 

The leaf of the Anacharis is composed of cells of an oblong 
form, but in some parts of the leaf becoming much elongated. 
At the margin of the leaf, which is toothed (each tooth con- 
sisting of a single somewhat triangular cell), the tissue of 
the leaf consists of a single layer of cells, the latter being 
more elongated in form than those towards the centre of the 
leaf. In these marginal cells, the green granules (chlorophyll) 
which they contain may be readily seen in rotation, thus indi- 
cating the currents of cell sap. The phenomenon is best seen, 
however, in those cells (very much elongated) which form the 
midrib of the leaf. (Granules are seen scattered about in the 
cells, a few in the centre of each cell are fixed. But there will 
be observed another set of spherules, forming a continuous 
line around the margin of each cell; these are in rapid 
motion, flowing along one side of the cell, generally with great 
regularity, till they arrive at the end, where they cross over 
and return by the other side, thus forming a continuous “ ro- 
tation” in the cell. The arrows show the direction of motion. 
Although the granules generally move on in this way, without 
interruption, closely following each other, still a casual inter- 
ruption occasionally takes place, and crowding ensues ; this is 
most frequent at the ends of the cells, at the “ crossing.” But 
the granules are gifted with even a greater share of politeness 


MEMORANDA. ay) 


than is usually to be found at a London crossing,—for when a 
crowding takes place, there is never seen an obstreperous 
granule trying to gain the precedence of his fellows, to get 
over first. When stagnation occurs, the granules behind con- 
tinue to move up in regular order, crowding in rear of those 
that preceded them, and not one will move till the one that 
first stopped begins to go on; nor is it crowded upon and 
pushed forward by those behind, as is usual in human society. 
With the greatest regularity each waits till the way is cleared 
for him, and then politely resumes his course to make way for 
his patient followers!) Slow movements of a similar nature 
are seen in the tubular cells of the stem of Anacharis. 

The movements in Anacharis very much resemble those 
seen in Vallisneria, but from the nature of the leaf they are 
much more easily observed in the former. I have been much 
interested in the subject, and have made a few observations 
from time to time, but defer their publication until I can find 
leisure to enter into a more complete examination of the phe- 
nomenon ; this especially, lest | incur the censure of those 
who regard the description of it given by Schultz as a “ pat- 
tern of imperfect observation, and unfortunate conclusions.” 

Rotation has been observed in the cells of the following, as 
well as of other, plants :— 


Chara and Nitella. Tradescantia virginica (hairs of 
Sagittaria sagittifolia. filaments). 

Stratiotes aloides. Campanula Medium (corolla hairs). 
Vallisneria spiralis. Marchantia (radical hairs). 
Zannichellia palustris. Mosses. 

Hydrocharis Morsus-Rane. Ceratophyllum. 

Potamogeton. Podostemacez. 

Equisetum. Lemna. 

Anacharis Alsinastrum. Lichens, 

Loasz (in stinging hairs). Arge. 

Urtica do. Fungi. 


As a hint to those who may wish to examine the rotation in 
cells, it may be mentioned that heat seems to increase tlie 
movements, and thus to lead to their more easy detection. It 
is therefore desirable to pursue such examinations in a warm 
room. — G. Lawson, Scottish Florist and Horticultural 
Journal. 


Rotation in the Wallisneria Spiralis. —It is stated in bota- 
nical works (Schleiden’s ‘ Principles of Scientific Botany,’ 
English translation, p. 94) that the circulation in the Vallis- 
neria continues for months after the leaf has been separated 
from the plant. I have recently had an opportunity of veri- 
fying this interesting fact. A portion of the leaf was given to 
me on the 15th of February last, and having kept it, changing 


56 MEMORANDA. 


the water occasionally, on the 2nd of August, after a lupse of 
Jive months and a half, had the pleasure of showing the circu- 
lation to several gentlemen (microscopists), though the leaf 
was then perfectly yellow. It may be as well to state, that up 
to about the conclusion of four months and a half there was no 
difficulty in seeing the circulation in any portion of the frag- 
ment; but, at the expiration of that period, it began to be 
more confined to single cells, so that, on the 2nd of August, I 
was some time in ‘finding a cell which exhibited the pheno- 
menon. I looked with great care on the 10th, and again on 
the 11th, but could not detect any circulation; the leaf appears 
now to be perfectly dead, and is much decayed. —G. Hunt, 
Liverpool. 


Holder.—Those who are engaged in mounting objects in 
the dry way for the microscope are aware that, for various 
reasons, it becomes necessary frequently to separate the slides 
which contain them, im order to examine the specimens before 
they are finally mounted ; more especially if they are under- 
going the drying process after maceration. ‘The slides are 
usually bound tightly with pieces of string or tape after each 
examination, or sometimes they are pressed with weights ; 
but, when time is of value, each of these plans is open to 
objection. I have, therefore, substituted a very simple con- 
trivance, which, while it maintains a constant pressure upon 
the glasses, can be removed or replaced without trouble or 
loss of time. It consists of two pieces of whalebone three 
inches and a half long tied or riveted together at each end ; 
and which, for convenience sake, may be called a holder. It 
fe well ty have ae eral of these holders at hand, and for this 
purpose, as well as to save the trouble of making them, I 
have requested Mr. Pritchard, of 162, Fleet-street, to prepare 
and keep some always ready for sale ; ; where they can be had 
singly, or by the dozen, at a moderate price. 


Brass Cementing Pencil.— When it is required to cement 
the thin glass cover to the slide, the usual method consists in 
melting a portion of the cement in a ladle. It is then painted 
round the edge of the cover and the contiguous surface of the 
slide with a camel’s hair brush, and smoothed off with a 


MEMORANDA. 57 


heated wire. The whole of these objects are effected by using 
the little instrument which I propose to call the cementing 
pencil. It is a brass tube, six inches long, 
with a conical bore, having a lid to screw on. 
When a small portion of the cement, crumbled 
into fragments, is shot into the tube, it is 
ready for use. 

In using this instrument the extremity is 
gently heated in the flame of a spirit-lamp, 
and when the cement begins to ooze out, 
holding the pencil like a pen, the point is 
traced along each side of the cover leaving 
a line of cement in the angle. It is thus laid 
on much easier than with a brush, and after 
a little manipulation it will be found that the 
point will suffice to polish off instead of using 
the flattened wire. 

I beg to recommend this to those who, like 
myself, pressed by professional avocations, 
are anxious to make the most of snatched 
intervals. And, I think, after resorting to 
various expedients, that, where it is desir- 
able to use cement this will be found the 
cleanest and most expeditious method. 

The cement suggested by Quekett is as follows :-— 

Electrical Coment. —‘ A very excellent cement is made by 
melting together two ounces of black resin, one ounce of bees- 
wax, and one ounce of vermilion.” 

This instrument can be procured at Mr. Pritchard’s.— 


Joun Goruam, Tunbridye, Kent. 


Binocular and Stereoscopic Microscope.—IThe attention 
given in the Microscopical Journal to the subject of binocular 
Vision induces me to submit to your readers an account of a 
prism or solid of glass, which, with the least possible loss of 
light, will enable one microscopic object-lens to furnish either 
a pair of stereoscopic pictures for the photographic camera, or 
two separate pencils of rays for the eye-pieces of a binocular 
microscope. The prism or solid to which I refer has been 
already employed as an erecting camera-lucida for the com- 
pound microscope and for the astronomical telescope, and is 
roughly represented in the accompanying diagram, fig. 1. 

The nature of solid will be readily understood. if st com- 
mon rectangular isosceles prisms be placed w a their largest 
faces in contact and with their axes perpendicular to each 
other, The prisms should have their largest faces of exactly 


58 MEMORANDA. 


the same size, but should differ in other respects, as shown in 
figs. 2 and 3. 

The effect, which a solid of this description produces upona 
pencil of rays incident centrally and perpendicularly upon 
either of its largest faces, is to divide it into two separate 
pencils which, after two internal and total reflections, emerge 
so as to form two inverted stereoscopic images of ie object 
from which the pencil first originated. This inversion is 
precisely that which is required for the binocular mic roscope, 
and enables a photographic camera to pr oduce a pair of stereo- 
scopic pictures by one operation. 

The mechanical modifications of Chevalier’s microscope 
(figured by Hanover, plate Il., fig. 2), or of Highley’s camera, 
represented in your last pueben will readily suggest ea 
selves to those who desire either a binocular erecting micro- 
scope or a stereoscopic photographic camera. —W. Hopeson, 


Old Brathay, near Ambleside, August 11, 1853. 


Method of applying Chemical Re-agents to Minute Quan- 
tities of Matter.—The usual method of testing a small quan- 
tity of a deposit or a drop of a solution with chemical re- 
agents, consists, as is well known, of allowing a drop to fall 
from the bottle containing the test, or of removing a small 
quantity of the solution upon a stirring-rod or pipette. In 
practice both these plans are often found inconvenient, parti- 
cularly in those instances in which the quantity to be tested 
is very minute, as often occurs in microscopical investigations. 

For some years past I have been in the habit of using little 
bulbs, terminating in capillary points for containing the tests, 

and from these the smallest quantity of the re-agent that can 

possibly be required, is readily expelled by the expansion 
of the enclosed bubble of air, when the bulb is inverted and 
held in the warm hand. 

The solution or deposit to be examined may be divided into 
several small portions, and placed upon one of the ordinary 
glass slides employ ed for mounting microscopical preparations. 
Each portion is then tested w ith a separate re-agent, as the 


a 


_— 


MEMORANDA. 59 


nature of the examination may require. About a dozen bulbs 
will contain all the re-agents required by the microscopist, 
and these may }e conveniently arranged in a smal Icase. 
Fig. 1. The bulbs may be made with gis, 9, 
the aid of the blow-pipe upon a r 


: piece of ordinary glass tube; they 
a should be about an inch in dia- 


meter. The tube may then be 
drawn to a capillary point, and a 
small cap, also of glass tube, 
adapted to the top. This may 
afterwards be ground to the neck 
in order to make it fit accurately. 
Or a cap is very readily made 
of a small piece of gutta percha; 
and this will be found to answer 
very well for those bulbs which 
S are not intended to contain acids. 2/7) 

ae (Fig. 4) eS 
The name or formula of each test may be written upon 
the neck of the bulb with a writing diamond, or painted 
upon it with a little black varnish. 

Mr. Highley has suggested an improvement in the form 
of these little vessels, which possesses many advantages. He 
has had little bottles made from thin glass tube, about half 
an inch in diameter, with capillary openings and ground glass 
tops. These have flat bottoms, so that they stand very well, 
and are more convenient for packing.* (Fig. 2.) 

Of filling the Bulbs with the Test Solutions——This is very 
readily effected by the application of a moderate heat to the 
bulb, the capillary orifice of which is inverted under the sur- 
face of the liquid which it is wished to introduce. The in- 
cluded air becomes expanded by the heat, and much escapes 
from the opening. Upon removing the spirit-lamp the fluid 
rushes into the bulb to occupy the place of the air which has 
been expelled. The bulb should not be more than two-thirds 
full of the solution, in order that sufficient air may be included to 
admit of considerable expansion when the warmth of the hand 
is applied to the bulb. This method of applying re-agents will 
be found very convenient in microscopical examination, in 
testing for carbonates, urinary calculi, &c., and with a very 
few drops of the test solutions a qualitative examination can 
be readily effected upon a quantity of substance far too minute 
for the ordinary methods of examination,—Lionet Bea.e. 


y ros 


* These may be obtained, arranged in cases, of Mr. Highley, 32, Fleet 
Street. 


60 MEMORANDA. 


New Microscopical Society.—On the 20th March, 1853, 
a Microscopical Society was founded at Dresden by Drs. 
Giinther, Pieschel, L. Rabenhorst, H. Richter, Stein, G. Struve, 
Zeiss, and Zenker. One of the provisions in the Rules of the 
new society declares, that there shall be no inactive members, 
so we ought to expect a good deal from its labours. 


Powell’s Condenser.—T hose who are interested in observing 
the improvements in microscopic apparatus, will be pleased 
to know, that with the new Condenser made by Powell and 
Lealand (a modification of Gillot’s), and an 3th object-glass, 
the Ceratoneis fasciolata can be demonstrated to be covered 
with dots similar to those of Navicula Hippocampus, though of 
course much smaller, I have used the No. 8 aperture, and the 
No. 4 stop. The dots are most easily demonstrated by day- 
light, and No. 2 eye-piece.--Tuomas Inman, M.D., Liverpool. 


Query.—In what work may there be found a description of 
the exceedingly beautiful structure of the proboscis of the fly, 
more especially, of what are termed, in the explanation of the 
plate, in the third number of this Journal, ‘divided absorbent 
tubes ”?—G. H., Liverpool. 


CPGE' 5 


PROCEEDINGS OF SOCIETIES. 


British AssociATION FOR THE ADVANCEMENT OF SCIENCE. 


The meeting was held this year at Hull. Several papers, in- 
volving microscopical research, were read. 

Professor Allman read three papers. 1. On the presence of 
Endochrome, developed from the interior of cells in a species of 
Conferva. 2. On the cellular structure of Hydra viridis, in which 
he maintained, in opposition to the views of Kélliker and Ecker, the 
distinctly cellular origin of the tissues of this animal. 3. On the 
structure of Bursaria and the nature of its nutrition. 

Dr. Redfern, of Aberdeen, made some remarks on the relation of 
bone and cartilage, an| drew attention to some observations which 
he had made which led him to conclude they were more intimately 
related than was generally supposed, and that cartilage was an 
incipient condition of bone. 

J. D. Sollitt, Esq., and R. Harrison, Esq., read a joint paper on 
the Diatomacez, which, from the interest of the subject at this time, 
we present entire. 


“ On the Diatomacee found in the vicinity of Hull. 


“No part of the kingdom is richer in Diatomacee than the 
vicinity of Hull; the low situation, and as it were terminations of 
the various waters as they come to the Humber, cause a deposit of 
these minute animals which have had their first being perhaps at a 
distance, and are then brought down to us by the currents, there to 
increase and multiply to a great extent; while at the same time the 
Humber, rich in the salt-water Diatomacee, deposits these in the 
various pools and holes into which the spring-tides reach, where 
they are left until the next spring-tide without being disturbed, and 
thus they are easily collected for the microscope. It may be justly 
observed that the Diatomacee are, of all others, the most beautiful 
of microscopic objects; their almost unlimited number, and the 
beautiful variety of their forms, are alone sufficient to fix the atten- 
tion and raise the admiration of the microscopist ; but in addition to 
this, they form a most useful resource in trying the excellence of 
various lenses, and as Test Objects for the microscope they are 
invaluable. The modern improvements in achromatic object-glasses 
have placed all the old test-objects in the background and ren- 
dered them almost useless; but the Diatomacee form a series 
of objects for this purpose, adequate for every improvement 
that has been or may be effected by the practical opticians 
either of this or of any other country. As Test Objects they have 
now been adopted by the scientific in all parts of the world, and for 
this adoption the optical world are wholly indebted to the Hull 
Microscopists. We in Hull first discovered the delicate markings on 


62 PROCEEDINGS OF SOCIETIES. 


their silicious coverings, and pointed them out to others as the proper 
tests for lenses. The first of the Diatomacezw on which the lines 
were seen was the Navicula Hippocampus of Ehrenberg, Pritchard, 
and Quekett: this discovery was made early in 1841, when speci- 
mens were sent to the Microscopical Society in London; but the 
London microscopists not being able to bring out anything but the 
longitudinal markings, a remark was published by Mr. Harrison in 
the Microscopical Journal for June 1841, stating that we had dis- 
covered cross striz: on the WV. Hippocampus, but that these 
were only visible on some of the specimens; on this they were 
immediately written to, and told that we meant to say there were 
both longitudinal and cross striz on the specimens sent. They, 
after labouring for nearly six months and frequently asserting 
that we were mistaken, at length saw the cross strie, and an 
account of our discovery then appeared in the Microscopical Journal 
for January 1842. The next specimen on which the markings 
were seen by us were the JV. dintata of Harrison ; this Navicula was 
unknown until 1843, at least it had not been described by any author 
before that time. In 1844 Mr. Soleitt was in London and showed the 
lines on this Navicula to Mr. Ross, with a 1-8th of Nachett’s, although 
Mr. Ross at that time could not bring them out witha very finel-12th 
which he had just finished; this little circumstance, trifling as it 
may appear, caused that eminent optician to alter the construction 
of his microscope, and to bring it into its present superior form. 
We afterwards discovered the lines on the V. angulata,the NV. Strigosa 
and, after much labour, those on the Ceratoneis Fasciola and the 
Navicula sigmoidea, and afterwards on the N. Areus ; which last is 
so extremely difficult, that, in order to even catch a glimpse of its 
delicate markings, the observer must be in possession of glasses of 
a very large angle of aperture and the finest definition, have the most 
careful management of oblique light, and in addition be possessed 
of a large share of patience. 

“The delicacy of the markings in these objects will be easily 
judged of from the number of striz on each which would be re- 
quired to make an inch : these are as follow :-— 


Strie. 

1 N. strigilis, Marine. . . 34,000intheimch 40 
N, Hippocampus, fresh water 42,000 $ 60 
; i Spencerii Quekett . ~- 50,000 = 70 
4) N. liniata and angulata, large 60,000 a 80 
N.angulata,small . . . 70,000 am \ 90 

N. strigosa, large . - + 70,000 ud 
Hi strigosa,small . . . 80,000 Es 95 
8)Ceratoneis Fasciola. . . 90,000 a 110 
N.sigmoidea. . - ~ ~ 105,000 - 120 
< N. Areus, = 2. ne « Jed,0u0 3 150 


“We have dwelt longer than we intended on these particular 
species on account of their value to the microscopist as test objects. 
We may observe that they are equally tests for defining power as they 
are for angle of aperture : take for illustration the NV. fasciola, witha 
1-12th object-glass and angle of aperture of 150° ; adjust the object- 


wo «e 


PROCEEDINGS OF SOCIETIES. 63 


glass for the proper thickness of glass covering the object, then by 
proper oblique light you will have the markings brought out beauti- 
fully sharp and distinct; alter the adjustment for the thickness 
of the glass, so as to deteriorate the defining power, and the markings 
will then scarcely be visible. 

** In addition to the riches of our neighbourhood in recent living 
specimens of these minute forms, we must not forget the very large 
bed of fossil Diatomacee which was discovered in Holderness 
whilst the workmen were employed in making a drain for carry- 
ing off the water from the low lands near Keyingham. Throughout 
the part which the drain intersects these fossil shells lay in 
some places so numerous as to form a bed of about two feet in 
thickness, many yards in breadth, and, for anything that we know to 
the contrary, it may be miles in length. In this bed of fossil 
Diatomaceze are to be found almost all the various forms of 
smaller Navieula, Eunotia, Cocconeis, Bacillaria, &c. The 
Eunotia granulata are very numerous in this bed, at least we found 
them so in several slides in our possession. 

** We may likewise state that amongst the remains of a forest buried 
in the sands on the Holderness coast, near Roos, we have found a 
very large number of fresh-water Diatomacez in a fossil state, 
particularly those common to our fresh-water ditches, and which 
are never found in salt water, although the sea now flows over this 
submarine forest at every tide. 

*¢ But to return to the subject of the immense numbers of beautiful 
Diatomacee found in our neighbourhood. It would be a vain attempt 
to try to give a description of each of them. I may observe that we 
have several species of Gallionella, almost every kind of Navicula 
Pritchard named, and a great many more which are not either 
in plates or named in his list. We have also several species of 
Eunotia, Cocconeis, Bacillaria, Tessella, Fragilaria, Meridion, 
Isthmia, Synedra, Podosphenia, Gomphonema, Echinella, Coc- 
conema, Achnanthes, and Frustulia; also the several species of 
living Xanthidia—mentioned in Pritchard. If we take Smith’s 
classification, of course the number of genera will be considerably 
increased, and even his species are not nearly sufficient to take in 
all that we have in this part of the country. We have seen in 
our waters nearly every one he has figured in the first volume of 
his work, and the few we have not seen is no proof that they are 
not to be found in this vicinity. 

‘¢ The places where we find the fresh-water Diatomacez are Spring 
Ditch, which is the old aqueduct that used to supply the town with 
water; the Cottingham Drain; and other similar runs of water, of 
which there are many in the neighbourhood. We may observe that 
on the other side of the Humber, at Burton, about five miles from 
hence, there is a stream of water very similar to our Spring Ditch, 
in which the fresh-water Diatomacez are sometimes so numerous 
that the whole surface of the mud is covered with them to the 
thickness of an inch or more. With regard to the salt-water species, 
as we have observed before, they are found in large quantities in 


64 PROCEEDINGS OF SOCIETIES. 


holes and ditches into which the spring tides reach. WV. Fascicola 
is found in large quantities in the Garrison Moat, into which the 
tide occasionally finds its way ; and in some of the stagnant waters 
by the side of the railway, along the South Humber Bank, as it 
is usually but improperly called, we find large numbers of the 
NV. liniata (attenuatus of Smith), and also the WV. angulata and 
strigilis. 

‘“We would just here observe that, when we first discovered the lines 
or markings on the various test shells which we have named in this 
paper, we sent specimens of them not only to the members of the 
London Microscopical Society, but also to.Mr. Smith, Mr. Ross, 
Messrs. Powell and Lealand, M. Nachet in Paris, and Professor 
Baily in America, the whole of which at once saw the excellency of 
those objects as tests for the microscope. Indeed they, are with- 
out doubt, to the microscope what the close double stars are to the 
telescope.” 

The paper was illustrated with diagrams, and a list of the species 
discovered in Hull was given. 


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TRANSACTIONS OF MICROSCOPICAL SOCIETY. 


DESCRIPTION OF PLATE I. VOL. II. 


Fig. 

1. Bacteriastrium furcatum. 

2, ————_-—— cu'vatum. 

3. Euphyllodium spathulatum. 

4, Triceratium sculptum. 

5. ——-———._ arcuatum. 
arbiculatura. 

7a. Triceratium contortum. 

*7b, ——_————- do. showing spine. 
8. Pleurosigma vallidum. 

9, —— —— inflatum. 

10, Amphitetras arisata. 

11, ——————_ tessellata. 

12. Eupodiscus crucifer. 

13. Campylodiscus latus. 

14, Asterolampra impar. 

15a & 15). Climacosphenia catena. 
16. Denticella simplex. 
17, ——-—— margaretifera. 


6, —— 


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Taffen West, ad nat. sculp 


JOURNAL OF MICROSCOPICAL SCIENCE. 


DESCRIPTION OF PLATE I. VOL. II. 
Figs. 

1 .—Four papille from the point of the finger ; the largest containing a 
tactile corpuscle with its nerves, while the others possess capillary 
loops. Acetic acid added—a, Nerves. 6. Neurilemma. c. ‘* Nu- 
clei.” d. Capillaries. 

2.—A papilla from the finger of a Tahitian, with a small tactile corpuscle. 
Letters as above. Acetic acid added. 

3. 4. 5.—Termination of nerve-fibres against tactile corpuscles. Caustic 
soda added. 600. ~ 

6.—Extremity of one of the papille at the base of a Frog’s tongue, the 
epithelium being stripped off. 

7.—A nerve, consisting of a single, dark contoured fibril in its neurilem- 
ma, from the human finger. 

8.—Portion of the wall of a Pacinian body from the human finger, 

9.—Section perpendicularly through one of the ridges on the beak of a 
Duck.—J. Horny layer of epidermis. m. Mucous layer. 7, Derma. 
p. Pacinian bodies. 

10. A single Pacinian body of the same. 


Diagrams. 
A.—Of a Tactile corpuscle. 
B.—Of a Pacinian body. 
C.—Of a Savian body. 
D.—Of the ‘“ Muciparous Canals” of Fishes. 
E.—Of a Vibrissa of a Rat. 


PLATE II. 


Illustrating Dr. Herapath’s Paper on Quinine in the Urine. 


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JOURNAL OF MICROSCOPICAL SCIENCE. 


DESCRIPTION OF PLATE I. VOL. II. 
Figs. 

L .—Four papilla from the point of the finger ; the largest containing a 
tactile corpuscle with its nerves, while the others possess capillary 
loops. Acetic acid added—a, Nerves. b. Neurilemma. c. ‘‘ Nu- 
clei.” d. Capillaries. 

2.—A papilla from the finger of a Tahitian, with a small tactile corpuscle. 
Letters as above. Acetic acid added. 

3. 4. 5.—Termination of nerve-fibres against tactile corpuscles. Caustic 
soda added. 600. ~ 

6.—Extremity of one of the papilla at the base of a Frog’s tongue, the 
epithelium being stripped off. 

7.—A nerve, consisting of a single, dark contoured fibril in its neurilem- 
ma, from the human finger. 

8.—Portion of the wall of a Pacinian body from the human finger. 

9.—Section perpendicularly through one of the ridges on the beak of a 
Duck.—J. Horny layer of epidermis. m. Mucous layer. m. Derma. 
p. Pacinian bodies. 

10. A single Pacinian body of the same. 


Diagrams. 
A.—Of a Tactile corpuscle. 
B.—Of a Pacinian body. 
C.—Of a Savian body. 
D.—Of the “‘ Muciparous Canals” of Fishes. 
H.—Of a Vibrissa of a Rat. 


PLATE II. 


Illustrating Dr. Herapath’s Paper on Quinine in the Urine. 


Mic Journ LAL L4 1 


‘THE aed. Toffen Weert, se Ford & West, inp 54 Hatter Garden 


eae 5 ee 


ORIGINAL COMMUNICATIONS. 


Some Observations on the Ittumination of TRANSPARENT 
Oxpsects. By Georce Rainey, M.R.C.S., Demonstrator 
of Anatomy and Microscopic Anatomy at St. Thomas's 


Hospital. 
(Continued from page 13.) 


I may observe, that 1 was rather surprised to see these 
images on globules of mercury even as large as 1-70th of an 
inch in diameter, especially as they occupied a part of the 
globule exactly opposite to that on which the light coming 
directly from the condenser fell. The illumination of this 
part of a globule cannot be attributed to radiated light, as 
none of the rays coming from below can reach it, and a mere 
image on a reflecting surface cannot be supposed capable of 
absorbing light, and therefore it cannot radiate it 

I may observe also that I found considerable difficulty in 
determining the cause of this fact, chiefly because the different 
circumstances under which it was examined gave such con- 
tradictory results. I first thought that an image was formed 
in the microscope which was reflected upon the upper surface 
of the globule, which I afterwards found to be only partially 
correct. My friend Dr. Bristow suggested the probability of 
its being a reflection from the lower surface of the object-glass, 
which was also in part correct; but as neither of these sup- 
positions satisfied al] the conditions under which these images 
were seen, I made the following experiments with a view to 
simplify, and therefore to facilitate, the examination as much 
as possible. 

I removed all the lenses from Gillett’s condenser, and em- 
ployed only the diaphragm with the flat side of a mirror, when 
I found, on examining globules of mercury with achromatic 
lenses of different magnifying powers, that images of the stops 
were formed as before, though very much more minute, and 
much less perfect. Hence I concluded that the appearances 
above described, although much exaggerated by condensing 
lenses, are not entirely produced by them. 

I next examined with a simple lens, of about one-inch focus, 
globules of mercury illuminated by Gillett’s condenser, and | 
found that when they were not covered by a piece of thin glass 
no image was formed upon them, but when they were covered, 
the thin glass being 1-200th of an inch above them, that a dis- 
tinct image of the stop was seen upon their upper surface. 

Hence in this instance, no doubt could exist as to the cause 
of the image, as it could only have been produced by the reflec- 

VOL, Ul. F 


66 ON THE ILLUMINATION OF TRANSPARENT OBJECTS. 


tion of the rays proceeding from the source of light, and im- 
pinging obliquely upon the under surface of the cover back- 

wards upon the upper surface of the globule, the figure of the 
stop being occasioned only by the quantity of light which it 
intercepted, and thus prevented from falling upon the glass, 
- and consequently from illuminating the globule. 

I next substituted for the simple lens achromatic lenses of 
one and two inch focus, and the result was precisely the same ; 
that is, when no cover was placed upon the object there was 
no image, but when it was, there was a distinct one. In all 
these cases the cover was 1-200th of an inch from the object : 
if this distance be increased beyond a certain limit, images 
will not be formed on the globules. The greatest distance for 
perfectly flat glass is about 1-30th of an inch; but if the glass 
be convex and the globule be placed beneath the centre of its 
convexity, the distance is very much increased, the amount of 
increase depending upon the degree of the convexity of the 
glass cover, 

I then examined an uncovered globule of mercury with a 
lens of 1-4th of an inch focus, on which I could perceive two 
imperfect and distorted images of the stop of the diaphragm. 
They were of different size, and did not appear to be exactly 
upon the same plane; the smaller one was the nearer and 
seemed to be much darker than the other. As in this case 
the distance of the object-glass from the object was less than 
1-30th of an inch, I concluded that the glasses composing it 
had reflected the images on the elobule, especially as there 
were two images, in the same way as the glass cover had 
done in the experiment with the simple lens and the low 
powers. 

Lastly, I substituted a half-inch for the quarter, and the 
result was the same as when the latter was used, excepting 
that one of the two images was very distinct and permanent, 
whilst the other one was fugacious, appearing and disappear- 
ing with the slightest movement of the head. The distance 
of this lens from the object exceeded the 1-30th of an inch, 
the limit at which images are formed on flat glass; but as it 
did not exceed the limit at which images are formed on convex 
glass, | concluded that these images were reflected by the 
glasses composing the objective, in the same way as when the 
quarter of an inch lens was employed, especially as two images 
were apparent. 

The inference, then, to be drawn from these experiments 
is, first, that the image of the source of light is larger with 
condensing lenses than with a plane mirror; secondly, that 
when low powers are used to examine covered objects the 


ON THE ILLUMINATION OF TRANSPARENT OBJECTS. 67 


images are produced by the reflection of the rays coming from 
the source of light, and falling obliquely upon the cover, 
backwards upon the object; but that, when high powers are 
used, those coming near to the object, the lenses themselves 
reflect the images on the object. 

But the formation of images like those above described is 
not confined to opaque metallic globules, since all transparent 
substances of a globular figure are well known to have the 
property of reflecting the images of objects thrown upon them 
by a reflector. However, the explanation just given does not 
apply to transparent but only to opaque globules. Among 
transparent bodies I have particularly observed this fact in 
some minute spherical calcareous bodies which were found on 
the capillaries of the brain; also in globules of oil, provided 
they are not too much flattened; in air bubbles, starch 
granules, spherules of glass, &c. &c. There is one circum- 
stance respecting all transparent globular objects worthy of 
notice, which is, the position of the image onthe globule. If 
a globule be of a refractive power greater! han that of the 
medium in which it is examined, the image of the source of 
light will be seen on its anterior surface, or a little in front of 
it: if these conditions are reversed it will be seen on its pos- 
terior surface, or a little behind it. Hence, if globules of oil 
be examined in water, the image of the stop of Gillett’s con- 
denser will be seen on their anterior surface, whilst, on the 
contrary, if globules of water be examined in oil, the image 
will be seen on their posterior surface. If a minute spherule 
of plate-glass be examined in water, the image of the stop will 
be seen on its anterior surface, but if the same spherule be 
examined in oil of cassia it will be seen behind it; whilst if 
the spherule be examined in Canada balsam, which has nearly 
the same refractive power as glass, no image will be visible. 

This fact furnishes the means of distinguishing one bedy 
from another by its refractive power, and is particularly ap- 
plicable to very minute particles. If, for example, there were 
suspended in water very minute spherules of calcareous matter, 
such as those I have mentioned, which look more like air than 
anything else, and globules of air, these would be readily dis- 
tinguished by the position of the image of the stop, the former 
having the image on its anterior surface, the latter on its pos- 
terior. 

As the distinctness of these images will depend upon the 
degree of transparency and homogeneousness of the bodies on 
which they are formed, and as their form will be very much 
influenced by the greater or less perfection of the spherical 
figure of the surface which reflects them, the strange appear- 

F2 


68 ON THE ILLUMINATION OF TRANSPARENT OBJECTS. 


ances which, from this cause, may mask and disfigure the 
true characters of microscopic objects, will be almost endless. 
And it must be remembered that these defects are common 
to all kinds of illumination of transparent objects in some 
degree or other. 

Notwithstanding these defects, from which I have shown 
that the most modern methods of illumination are not free, we 
have in the latest improvements the means, not only of ren- 
dering them of but little account, but of converting them into 
advantages as useful aids in microscopic analysis. 

In the experiments on the globules of mercury it was ob- 
served that when a number of globules were in one field of 
view, an image of the stop of Gillett’ s condenser was seen on 
all of them. AN it must be further observed, that as all 
these appearances are secondarily the reflection of only one 
magnified image of the stop, which can be seen by a low 
power, situated on a plane posterior to that on which objects 
are visible, and exactly in the axis of the microscope, only that 
globule whose axis coincides with that of this image can have 
upon it a perfectly symmetrical figure of the stop; upon all 
the others this image will be distorted, the degree of distortion 
being proportional to the remoteness ‘of the globule from the 
axis ob tle microscope. 

This applies equally to all objects, transparent as well as 
opaque. Hence we see, that all appearances of an object 
which are not the same when it is placed in the centre 
of the field of view as when it is placed near its margin 
are spurious. It must be remembered that the difference of 
focus, although never so slight, consequent on removing the 
object to different parts of the field, must be taken into con- 
sideration, and that when the object is removed from one part 
of the field to another each position requires a fresh focus. 

I will give one example. If one of the pale shells of the 
guano be illuminated by Gillett’s condenser, the smallest stop 
being under the lenses, and examined by a lens of one-eighth 
focus, it will present a reticulated appearance, the true nature 
of which is not very evident ; however, as thus illuminated, 
the meshes will present different appearances, according to the 
focus at which they are seen, and these appearances will vary 
as the object is being removed from one part of the field to 
another, showing them to be the reflection of something 
situated in the axis of the microscope. If, now, the object is 
so focused that the dark spots in those meshes which are 
situated in the centre of the field is made as distinct as 
possible, and the condenser is rotated, the spots occupying 
these meshes will be seen to move, mad be recognisable as 
the images of the stop of the diaphragm of the condenser. 


ON THE ILLUMINATION OF TRANSPARENT OBJECTS. 69 


The appearance, although much less distinct, will be pre- 
cisely the same as that presented by the compound cornea of a 
very minute insect, when examined under the same circum- 
stances. Hence the true structure of such shells as these is 
manifestly lenticular, that is, each space is filled up by trans- 
parent material in the form of a convex lens. 

I might give many other examples, but this will probably 
suffice to show to what use the facts which I have mentioned 
may be applied. The use of Mr. Gillett’s condenser in this 
kind of analysis might be extended, if something more charac- 
teristic than a stop were placed in one of the perforations of the 
diaphragm, as, for instance, a small cross. 

I will now conclude this paper by some observations upon 
dark-ground illumination, as shown by Mr. Gillett’s condenser, 
and Mr. Wenham’s paraboloid. 

If a globule of mercury, illuminated by Gillett’s condenser, 
with one of the stops under the condensing lens, be examined 
by a very low power—a one or two inch lens—it will have 
the appearance of a dark disk surrounded by a circle of light, 
and if it be covered with thin glass, there will be an image of 
the stop at its centre, but not otherwise. In this case the 
object is seen on a dark ground, which is the magnified image 
of the stop interposed between the object and the light, and 
thus all the central rays of the illuminating pencil are cut off; 
and, as the rays which are thrown immediately upon it are 
considered to have a degree of obliquity given to them by the 
margin of the stop, too great to allow of their entering the 
microscope, the object is thought to be rendered visible only 
by the light which it radiates as if it were self-luminous. As 
this mode of illumination is precisely the same as that with 
the paraboloid, [ will defer the further consideration of ra- 
diated light until the action of that instrument is explained. 

For this purpose it will be necessary to repeat the exa- 
mination of the globules of mercury, when illuminated by the 
paraboloid, first when uncovered, and afterwards when covered 
with a piece of thin glass, situated about 1-200th of an inch 
from the object. In the first case the globules will appear to 
be surrounded with a circle of light, in which the cross-bar 
contained in the tube of the paraboloid, or eny other object 
reflected upon the tube by the mirror, can be seen. In the 
second case there will be two circles of light—an external one, 
which is the same as that just described, and an internal one ; 
the latter is the image of the end of the paraboloid reflected 
upon the mercury by the glass cover. The cross-bar and 
other objects are also seen, as in the first case. 

I may observe that in all these experiments I have not 
thought it necessary to notice the various appearances pro- 


70 ON THE ILLUMINATION OF TRANSPARENT OBJECTS. 


duced by the reflection of different parts of the microscope, 
as the extremity of the object-glasses, &c., upon the objects, 
as these can be easily recognised. 

Now, according to the theory of the illumination of. micro- 
scopic objects by radiated light, “all objects, either trans- 
parent or opaque (excepting white), absorb some of the rays 
of light falling upon them,” and are rendered visible by the 
portion which they. radiate. Hence Mr. Wenham observes, 
‘that no rays from the source of light should enter the object- 
glass by passing through or around the object, which must 
be illuminated by very intense light, thrown on it, in all or in 
opposite directions, at an angle exceeding the aperture of the 
object-glass, so that the light which enters the microscope 
should be that which radiates only from the object as if it were 
self-luminous.” 

Asa great part of the luminous appearance presented by 
the covered globule of mercury has been shown to be due to 
the light first reflected from the glass parabola upon the glass 
cover, and then by the latter upon the upper surface of the 
globule, that much of the appearance cannot be the effect of 

radiated light. ‘The glass cover having in this instance served 

the purpose of a Lieberkiihn, has made the object appear 
in a false light; and as nearly all microscopic examinations 
are made on covered objects, the paraboloid is in this respect 
defective, and the error must always be allowed for. It is 
true that all objects are not spherical, and, therefore, do not 
possess the property of reflecting perfect images, yet they will 
derive some portion of the rays by which they are illuminated 
from the reflection of the source of light upon them, in the 
same way as if they were globular. 

With respect to the illumination of uncovered objects, ex- 
periment is SNELL at variance witha leading postulate of the 

radiated-light theory, which is, that no rays from the source 
of light passing around the object enter the object-glass ; for 
if this were true, the image of objects reflected by a plane 
mirror up the tube of the paraboloid could not be seen by a 
two-inch lens of 12° angle of aperture. 

This will be best understood by referring to the adjoining 
diagram, in which A is to represent the paraboloid, B a com- 
pound microscope, CD an object-glass of two-inch focus and 
12° of angular aperture. Now, suppose (m, 7) a ray of light 
coming from a part of the window-frame, or from close to the 
outer side of the cross-bar within the tiiba of the paraboloid, 
to be thrown upon the point (x) of the parabolic reflector, it 
will be so reflected as to pass through the focus (f), and con- 
tinuing in the direction (n, f, g), it cannot, under the conditions 
specified, enter the microscope, and consequently the part 


ON THE ILLUMINATION OF TRANSPARENT OBJECTS. 71 


from which it emanated would not be visible. But these are 
not the sole conditions : for, suppose a globule of mercury to be 
placed at f, then it is very easy. to see how this same ray 
(n, f ), by being reflected in the direction f, ¢ c, and making the 
angle of gelleation equal to the angle of incidence, would pass 
through the objec t-glass, CD, and form an image of the point 
from eich it had proceeded, according to the common laws 
of refraction ; and it is in this way the object is seen. Now, 
as what is fae with respect to this ray applies equally to 
every other ray thrown by the parabola upon the margin of 
the globule, we may conclude that 
it is the light which is reflected 
from its entire circumference which 
produces the appearance of the cir- 
cle of light before described ; and 
so also if there were any number of 
globules, each would be surrounded 
by, a ring of light reflected from 
it in the same manner. 

But if we suppose any other 
substance, possessing in a much 
inferior degree the property of re- 
flecting light, to be situated in am 
place of the globule of mercury, i 
will be SMerainntedl 3 in the same way 
by the rays concentrated upon it 
by the parabolic reflector, which 
rays it will reflect also according to 
the same law; and such an object 
would no more be seen by radiated 
light than the picture of a portion 
of the window-frame on the upper 
surface of a globule of quicksilver 
would be. This explanation of the 

manner in which objects are seen 
as illuminated by the paraboloid, 
is equally applicable to the same 
objects when illuminated by Gillett’s condenser, and ex- 
amined by a low power. I may further add that this ex- 
planation is in accordance with the simplest laws of optics, 
that it agrees in every respect with experiment, and that it 
assumes no endowment of material substances with proper- 
ties which they are not well known to possess. 


Greta) 


On a Microscope adapted for AnatomicaL DEMONSTRATIONS 5 
and on a Brnocutar Microscorr. By M. Nacuet, of Paris. 


ALL micrographers have felt the difficulty of defining the 
nature and situation of an object in the field of a microscope 
so as to make it ¢ appar ent to several persons. I need not ex- 
plain that this arises from the number of different objects 
visible at the same time, and often also from the moving of 
the objects themselves in fluids, particularly infusoria, which 
it is impossible to show in the same state in which one has 
observed them oneself. 

These difficulties are experienced still more in the demon- 
stration of microscopical dissections ; for the observer, to avoid 
losing considerable time, exhibits only the result of his opera- 
tions, and not the method by which he arrived at it, though 
that is also very important. The problem then has been, how 
to enable two or more persons to observe at one time the same 
object. 1 believe I have resolved this difficulty by the con- 
struction of the instrument represented in fig. 1, with which 


(Se ie 


two persons looking through the eye-pieces, C ©’, obtain each 
an erected image of the object : the division of the pencil of 
light formed by the objective, A, is accomplished by a prism, 
P, fig. 2, the section of which is an equilateral triangle; the 
image reflected upon the face a emerges normally upon the 
face b, that reflected upon 5 also emerges upon the face a; 
there is thus formed on the right and left of the instrument an 
image erected in a certain sense; if upon the transit of these 


MICROSCOPE FOR ANATOMICAL DEMONSTRATIONS. (EE 


rays the prisms, B B' fig. 1, are placed, similarly to the sepa- 
rating prism, but so disposed that their reflecting surfaces are 
perpendicular to the central prism, the object Swall then be 
completely erected on each side, which is a considerable ad- 
vantage for the demonstrating of dissections; moreover, the 
two observers can place themselves on the same side of a table, 


for the eye-pieces are brought nearly into the same plane as 
regards the prisms B DB’, and are placed at a very convenient 


apeitnuion for avoiding fatigue to the head. If the two 
have not the same focus, one is first adjusted by the pinions 
and screws, and the other by drawing Fig. 3. 


out and pushing in the tube carrying 
the oculars. If a vertical view be de- 
sired, the screw-heads I) D’ have only 
to ba. turned and the prisms B B’ to be 
revolved a quarter round, to obtain an 
effect exactly opposite to the preceding 
one, that is to say, that the images are 
reversed as in an ordinary microscope, 
for the faces of B BY, fig. 1, becoming 
parallel to those of the central prism, 
destroy the first erection caused by it. 

It will be seen that by leaving B in- 
clined and by bringing B’ into the per- 
pendicular, a person looking i in C will 
have an erected image, whilst another 
looking vertically in C’ will have a re- 
versed image. 

The parallelism of the oculars CC’, 
when they are ina vertical plane, brings 
to mind Professor Riddell’s valuable 
method of simplifying theconstructionof 
binocular microscopes, for if the prisms 


74 ON A BINOCULAR MICROSCOPE. 


B B’ are brought towards the central prism, as in fig. 3, the 
oculars C C’ are placed so as nearly to suit the ae 
between the eyes. 

Fig. 4 shows sufficiently well the course of the rays, and 
requires no further expla- 
nation ; I shall only remark 
that the rays, a b a’ b’, al- 
ways emergingnormally on 
the terminal faces, there is 
no chromatic dispersion ; 
and the superior angle of 
the prism being very acute, 
and the surfaces perfectly 
even (which is not difficult 
of execution), the loss of 
light is almost inappreci- 
able. There isa great ad- 
vantage attached to this 
arrangement in the im- 
possibili ity of pseudose opic 
effects arising, as in Pro- 
fessor Riddell’s last and 
definite arrangement, or in 
Mr. Wenham’s very inge- 
nious refracting prism. When the distance between the oc -ulars 
requires to be modified, the screws V V’ are used for moving 
the lateral prisms nearer or further off at pleasure. 

The phenomena of complementary colours produced by 
polarization can be examined with this instrument in the most 
simple manner; and with regard to crystals, it is certainly one 
of the most beniwtifal spectacles to behold a crystal in relief, 
appearing tinged with complementary colour to the single eye, 
while to binocular vision it becomes white, as if it were not 
seen under polarized light. 


Fig. 4. 


On the Uttimare Structure and RELATIONS of the MALPIGHIAN 
Boptgs of the SpLEEN and of the Tonsituar Fotiicies. By 
Tuomas Houxtey, F.RS. 


Tue first account of those peculiar whitish corpuscles, disco- 
vered by Malpighi and to be met with, more or less distinctly 
marked, in the spleen of every animal, which at all satisfies 
the requirements of modern satan science, was given by 


Professor Miller, in his Archiv. for 1834. Miller dexoribes 


with great accuracy the mode in which these bodies are supplied 


~ 


ON THE STRUCTURE OF THE MALPIGHIAN BODIES. i) 


by minute arteries, and explains that they are, in fact, out- 
growths of the adventitious tunic of those arteries. He states 
that, by means of fine injections, he found that “the arterial 
twigs sometimes passed by the side of the Malpighian bodies 
without giving off any branches to them—sometimes went 
straight through the whole body or a part of it, in which case, 
however, no portion of the arteries terminated inthem. These 
fine arterial twigs appear less to pass through the middle of 
the corpuscles than to run on their walls and then to leave 
them. When an arterial twig divides into many minute 
branches in the Malpighian body, which never takes place 
upon its surface, but always in the thickness of its walls, these 
arterioles pass out again to be distributed as very minute 
branches in the surrounding red pulp: in fact, the ultimate 
termination of all the finest penicellate arteries is in this red 
substance. From all this I have become convinced that the 
white bodies, as mere outgrowths of the tuniee adventitiv, have 
no relation with the finest ramifications of the arteries.” 

With regard to another important point,—whether the 
Malpighian bodies are hollow or solid—Professor Miiller’s 
statements are less definite. In the commencement of his 
article he affirms, in opposition to Malpighi and Rudolphi, 
that they are solid, but at the end he qualifies this opinion : 
“1 was long of opinion that the white bodies are not hollow, 
but merely filled with a white pulpy substance, which might 
indeed be pressed out of them, but was not distinctly defined 
from the walls of the bodies. Further observations recently 
made, however, have instructed me that the white granular 
substance which is contained in the Malpighian bodies is too 
fiuid, while on the other hand their walls are too solid, not 
to oblige us to regard them as a kind of vesicles with tolerably 
thick walls. The white clear fluid (breiige) matter which they 
contain consists for the most part of equal-sized corpuscles, 
which are about as large as the blood-corpuscles—not however 
flat, like these, but irregularly globular. These corpuscles 
present exactly the same microscopic appearance, and are of 
the same size, as the granules of which the red substance of 
the spleen is composed.” Pp. 88, 89. 

Although the Malpighian bodies have been the subject of 
frequent and repeated investigations since 1834, I think that 
more has been done to confuse than to improve the above (in 
its general outlines) very accurate account of their structure. 

Giesker, in a work which I have not seen (Splenologie, 1835, 
cited by both Henle and Kdlliker), appears to have been the 
first to diverge from Miiller’s views. He states that there is a 
delicate membrane investing the proper membranes of the 


76 ON THE STRUCTURE OF THE MALPIGHIAN BODIES, 


Malpighian bodies in which arterioles ramify—and thus the 
latter never enter the Malpighian bodies at all (Henle, Allg. 
Anat. p. 1000) ; and Kolliker, Gerlach, and Sanders (On the 
Structure of the Spleen, Annals of Anat. and Phys. 1850), 
agree with Giesker on the latter point. 

In the meanwhile, however, Giinsburg (Zur Kenntniss des 
Milz-gewebes, Miill. Arch. 1850) had confirmed and extended 
Miiller’s observations with regard to the distribution of the 
vessels in the Malpighian bodies. He says, p. 167, “ Their 
framework is a vascular plexus. The larger vessels (cylinder) 
are longitudinally triated, in consequence of the regular 
arrangement of the nuclei upon their walls, the smaller are 
simple tubes.” These observations were made on persons who 
died of cholera. 

In January, 1851, Dr. Sanders read a paper ‘ On the con- 
nexion of the minute Arterial Twigs with the Malpighian 
Sacculi in the Spleen,’ before the Edinburgh Physiological 
Society, in which he describes a peculiar method of prepa- 
ration of the pig’s spleen, whereby arterial twigs may be de- 
monstrated ‘ passing diametrically across the area of the 
sacculi.’ ‘ Stains of blood also, often in linear arrangement, 
indicating capillaries, were seen in the interior of the sacculi.” 
Kolliker (¢ Mik, Anat.’ and ‘ Handbuch,’ 1852), while denying 
the entrance of the arterial twigs into the Malpighian bodies, 
states that he had just succeeded in once observing a network 
of fine capillaries in those of a cat, and he supposes that they 
will hereafter be discovered in other animals. Finally, 
Mr. Wharton Jones speaks doubtfully of having observed a 
single capillary tube in the Malpighian bodies of the sheep. 
(On blood-corpuscle-holding cells.— Brit. and For. Med. Chir. 
Review, 1853), The existence of a special continuous mem- 
brane investing the Malpighian bodies is affirmed by Ecker, 
Gerlach, Kolliker, and Sanders. On the other hand, it is 
denied by Henle (Allg. Anat. 1001), and by Wharton Jones 
Lee,) 

With regard to the contents, Miiller’s statements, as we have 
seen, waver. Henle, Gerlach, Kolliker, and Sanders say that 
they are composed of corpuscles suspended in a fluid. ‘The 
quantity of the latter is however, according to Kolliker, small. 

I may now proceed to communicate the results of my own 
observations upon the structure of the Malpighian bodies in 
Man, the Sheep, Pig, Rat and Kitten, and I will arrange what 
I have to say under the three heads of—1. The distribution of 
the vessels of the Malpighian bodies. 2. The structure of 
their substance (so-called contents), or the Malpighian pulp. 
3. The structure of their peripheral portion, or so-called ‘ walls.’ 


ON THE STRUCTURE OF THE MALPIGHIAN BODIES. 77 


l. The Distribution of the Vessels of the Malpighian Bodies. 


In all the animals above mentioned, I find it very easy to 
demonstrate, in almost every case, that one or more minute 
arterial twigs enter and frequently subdivide in the substance 
of the Malpighian body, making their exit on its opposite side, 
to terminate, finally, by breaking up into minute branches in 
the pulp. Indeed, it is so easy to convince oneself of this 
fact, if a thin section of a fresh spleen be examined under the 
simple microscope, that it is difficult to understand how two 
opinions can exist upon the subject. The method I have 
adopted is simply this: to such a section I add some weak 
syrup, so as to retain the colouring matter in the blood-cor- 
puscles contained in the vessels, and thus to have the advantage 
of a natural injection; then, I either trace out the vessels into 
the Malpighian bodies with needles, under a 41-inch lens; or, 
placing a glass plate over the section, I apply a gentle and 
gradual pressure, just sufficient to render the bodies transparent. 
It is then easy, by sliding the plate with a needle, to cause 
the bodies to roll a little upon their axes, and thus convince 
oneself, by the relative positions which the vessels and the 
bodies assume, that the former do really pass through, and not 
merely over, the latter. In Plate III. (figs. 1,2, and 7) I have 
represented the ordinary modes in which the arterial twigs are 
disposed in the Malpighian bodies of the sheep (figs. 1, 2) 
and of Man (fig. 7). It should be observed, however, that the 
Malpighian bodies have by no means always the well-marked 
oval outline which is here represented. On the other hand 
they are very frequently diffuse and irregular, sending out 
processes along the efferent and afferent twigs, 

The application of a high power, either to the compressed 
Malpighian body, or to one which has been torn out with 
needles and its vessels isolated, fully confirms the results ob- 
tained by the previous methods. In Man, the structure of the 
minute arterial twigs within the bodies does not differ from that 
which they possess elsewhere (fig. 7). Both the transversely 
(smooth-muscular) and longitudinally fibrous coats are well 
developed, neither being in excess; and the addition of acetic 
acid produces a clear line external to the former, representing 
the innermost portion of the tunica adventitia, which passes 
into, and is continuous with, the Malpighian pulp. The 
artery, therefore, is not only surrounded by, and in immediate 
contact with, the indifferent tissue of the pulp, but the latter, 
as Miiller pointed out, is really the representative of a part of 
its tunica adventitia. In fact, the indifferent tissue so com- 
pletely forms an integral constituent of the coat of the artery, 
that I could not, in any way, obtain the latter free from it. 


78 ON THE STRUCTURE OF THE MALPIGHIAN BODIES. 


In the Sheep, the arterial twigs have precisely the same 
relation to the Malpighian pulp, but the intimate structure of 
their walls is different, the circularly fibrous layer becoming 
almost obsolete, while the longitudinally fibrous coat acquires 
proportionally increased dimensions, and takes, at the same 
time, the structure of organic muscle. In the small arterial 
twigs of 1-800th inch in diameter, represented in fig. 3, the 
cavity of the vessels did not occupy more than one-third of 
their diameter, and,. like the efferent ramuscules, unless they 
contained blood, they resembled mere trabecule, consisting of 
organic muscle. 

"The yescels within the Malpighian hates are, however, not 
arterial ramifications only: I find that there invariably exists, 
in addition, a tolerably rich network of capillaries connecting 
the arterial ramuscules. These capillaries are vessels of 
1-1000th to 1-3000th of an inch, or even less, in diameter, 
which can hardly be said to have parietes distinct from the 
surrounding indifferent tissue of the pulp (figs. 3 and 8) ; unless 
they are filled with blood, indeed, they are not distinguishable 
with certainty; and in ‘the figures 2 and 7,1 have, there- 
fore, only represented those fragments of the capillary network 
in which blood corpuscles were clearly distinguishable, their 
colouring matter being retained by the syrup. After the 
addition of water, it is often impossible to recognize the capil- 
laries at all; but using syrup, I have readily enough seen them 
in all the animals above mentioned. 

It may then perhaps be fairly concluded that, in mammals, 
the Malpighian bodies are traversed by minute arteries, and 
contain, in addition, a network of capillaries. 


2. The Structure of the ‘ Contents” or Pulp of the Malpighian 
Bodies. 


Almost all writers have agreed in stating that the interior 
of the Malpighian bodies is filled by a liquid, consisting, as 
KGlliker says, of a small quantity of fluid with a large propor- 
tion of corpuscles. However, I have been quite unable to con- 
vince myself of the existence of any fluid matter at all in the 
interior of the perfectly-fresh Malpighian bodies of any of the 
animals 1 have examined. On the other hand, the Malpighian 
pulp appears to me to be as solid as any other indifferent tissue, 
e. g., that which constitutes the lowest layer of an epidermis 
or epithelium, or as the most superficial portion of any dermal 
structure. It is, indeed, like these, soft and capable of being 
crushed into a semifluid substance, which becomes diffused in 
any surrounding liquid, like mud in water; but that it isa 
soft solid and not a fluid, results, [ think, from what I have 


ON THE STRUCTURE OF THE MALPIGHIAN BODIES. 79 


stated with regard to the difficulty of completely detaching it 
from the arterial twigs. 

The essential structure of the Malpighian pulp appears to 
me to be that of every other indifferent tissue which I have 
yet examined; it consists, in fact, of a homogeneous, trans- 
parent, structureless matrix, or periplast, containing closely-set 
rounded or polygonal vesicular endoplasts: these vary in dia- 
meter from less than 1-5000th inch up to 1-2500th, or a little 
more, and contain usually one to three, but frequently many, 
minute granules* (fig. 4). On the addition of acetic acid, the 
periplast often becomes granular and less transparent, while 
the endoplasts are rendered darker and more sharply defined, 
undergoing a certain wrinkling. There are neither cell 
cavities nor cell walls distinguishable around these endoplasts, 
and therefore the Malpighian pulp cannot be said to be 
composed of ‘nucleated cells ;? resembling, in this respect, 
all the primary, unmetamorphosed tissues with which | am 
acquainted. 

True cells are, however, to be met with here and there in 
the Malpighian pulp. There is first to be observed a clear 
area, as of a cavity, surrounding an endoplast ; the periplast 
forming the outer limit of this clear area then acquires a more 
distinct definition (fig. 5), and becomes recognizable as a cell- 
wall, from the remaining periplast. Such complete cells 
measure from 1-2500th to 1-1500th of an inch in diameter. 
A further change is undergone by the periplast within and 
around some of these cells ; granules are deposited, which are 
sometimes minute and colourless, sometimes, on the other 
hand, have a deep-red colour and a considerable size, consti- 
tuting the well-known ‘ pigment-globule-cells’ of the spleen ; 
but I may remark, that I have never been able to observe any 
blood corpuscles in such cells. 

If the Malpighian pulp be pressed out or torn with needles, 
it is very readily broken up and diffused through the surround- 
ing fluid. We then find in the latter free endoplasts—endo- 
plasts surrounded by definite cell walls and cell cavities—and 
granule and pigment cells, corresponding with the elements 
which were observed in the uninjured tissue. That the free 
cells were not primarily independent structures, but have 
simply resulted from the breaking up of the periplast along 
its lines of least cohesion, is evidenced, in a yery interesting 


* These therefore correspond with the “‘ nuclei” and “ nucleoli ” of authors. 
The reasons for not so denominating them are contained in an article ‘On 
the Cell Theory’ (‘ Brit. and For. Med. Chir. Review, October 1853’). I 
may observe that I know of no tissue better calculated to illustrate the 
view which I have there taken of Histogenesis, than the Malpighian pulp. 


80 ON THE STRUCTURE OF THE MALPIGHIAN BODIES. 


manner, by such forms as are represented in fig. 6, where two 
cells may be observed still connected by a bridge of peri- 
plastic (or as it would here be called, in the language of the 
cell theory, ‘ intercellular’) substance, while the outline of a 
single isolated cell is still irregular and granular, from the 
adhesion of particles of the periplast of which it once formed 
a portion. Such bodies as these are quite undistinguishable, 
structurally, from pus, mucus, or colourless blood corpuscles.* 


3. The Peripheral portion, so-called “Wall,” of the Malpighian 
Body. 

In the human spleen, the Malpighian bodies cannot be said 
with any propriety to possess walls. Their structure remains, 
as we have described it, up to their junction with the sur- 
rounding red pulp. At the line of junction, a somewhat more 
condensed tissue, which breaks up, like a great deal of the red 
pulp, into spindle-shaped bodies, and those fibres with one- 
sided endoplasts, described by Kolliker, may be found; but 
this tissue belongs as much to the red pulp as to the Mal- 
pighian body. 

In the Sheep, on the other hand, I find, to quote Mr. Whar- 


ton Jones’s words, that— 


‘* Examined with a low magnifying power, the Malpighian cor- 
vesicles present the appearance of thick-walled, glandular vesicles, 
with contents. . The thick walls are not defined and homogeneous, 
but are, on examination with a high power, found to be composed 
of nucleated fibres and nucleated corpuscles, similar to those of the 
red pulpy substance, between which, indeed, and the exterior surface 
of the Malpighian corpuscles there is no very distinct line of de- 
marcation other than is produced by the condensation of the wall of 
the Malpighian corpuscles and the absence in them of coloration.” 


In addition to this, however, I find upon the exterior of the 
Malpighian bodies in the Sheep the mesh-work of pale fibres, 
(fig. 2, d’,) like very young elastic tissue, or the fibres of the 
zonule of zinn, to which Kolliker and Sanders have referred ; 
and I have occasionally met with such fibres in the interior of 
the bodies themselves, traversing the Malpighian pulp. They 
appear to me to belong to the original tunica adventitia of the 
arteries. The existence of any distinct structureless limitary 


* The above account of the structure of the Malpighian bodies is 
essentially identical with that given by Mr. Wharton Jones, 1. c. pp. 34, 35, 
but was drawn up before I had the good fortune to become acquainted 
with his article. He describes the wall of the nucleated cells as being 
“not very smooth,” and the periplast as a “ diffluent intercellular sub- 
stance,” whence I presume that I may,quote him as an authority for the 
absence of fluid in the Malpighian bodies. 


ON THE STRUCTURE OF THE MALPIGHIAN BODIES. 81 


membrane may, I think, be very decidedly denied ; and with 
regard to the “granular membrane, the internal surface of 
which is lined by a layer of large nucleated cells, while free 
nuclei or corpuscles, with a homogeneous or granular plasma, 
fill its interior” (Sanders, 1. c., p. 35); all I can say is, that I 
cannot give any opinion as to what it may be, never having 
met with a Malpighian body presenting any such structures. 

It may be said, then, that the Malpighian bodies of the 
mammalian spleen are not closed follicles, and have no 
analogy whatever to the acini of ordinary glands, but that they 
are portions of the spleen, everywhere continuous with the 
rest, but distinguished from it—a, by immediately surrounding, 
and as it were replacing, the tunica adventitia of the arteries ; 
b, by containing no wide venous sinuses, but, at most, a net- 
work of delicate capillaries; and c, by being composed of ab- 
solutely indifferent tissue, 7. e. of a structureless periplast with 
imbedded endoplasts—or of a tissue in which the periplast 
has undergone no further metamorphosis than that into cell- 
wall and rudimentary fibre. 

For a demonstration that each of these propositions holds 
good of the Malpighian bodies in the other three classes of the 
Vertebrata, I must refer to. Remak’s very able essay, ‘ Ueber 
Pigment-kugel-haltige Zellen,’ in Miiller’s ‘ Archiv.’ for 1852, 
and to Leydig’s recent ‘ Untersuchungen iiber Fische und 
Reptilien,’ in which ample evidence of the fact will be found ; 
and my limits oblige me to allude, with equal brevity, to 
another important doctrine which many recent writers have 
maintained, but which is especially enunciated and illustrated 
by Leydig, namely—that there is no line of demarcation to be 
drawn between the spleen, the lymphatic glands, Payer’s patches, 
and the glandule solitarie, the supra-renal capsules, the 
thymus, and the pituitary body, but that these form one great 
class of glands characterized essentially by being masses of 
indifferent tissue contained in vascular plexuses, and which 
may therefore well retain their old name of Vascular Glands. 

The primary form of these is represented by the solitary 
gland of the alimentary canal, which is nothing but a local 
hypertrophy of the indifferent element of the connective tissue 
of the part, and possesses no other capsule than that which 
necessarily results from its being surrounded by the latter. 

A number of such bodies as these, in contiguity, constitute, 
if they be developed within a mucous membrane, a Payer’s 
patch; if within the walls of the splenic artery and its ramifi- 
cations, a spleen; if within the walls of lymphatics, a lym- 
phatic gland ; if in the neighbourhood or within the substance 
(as in Fishes) of the kidney, a supra-renal body ; if in relation 

VOL, If. G 


82 ON THE STRUCTURE OF THE MALPIGHIAN BODIES. 


with a part of the brain, a pituitary body.* All these organs 
agree in possessing nothing that can be called a duct. To 
those, however, which are in relation with mucous membranes, 
KGlliker has already justly shown (‘ Handbuch’ and ‘ Mikr. 
Anat.’) that the ‘follicular’ glands of the root of the tongue 
and the tonsils must be added; the former of which possess 
rudimentary, and the latter a tolerably perfect, system of 
ducts, formed by diverticula of the mucous membrane, 
around which the elements of the vascular gland are arranged, 
though they are not directly connected with them. I can 
fully testify to the general accuracy of K@lliker’s account of 
the structure of the tonsils; but I must add that I have been 
unable to find ‘ closed follicles’ either in Man or in the Sheep; 
and, on the other hand, that the indifferent tissue of the so- 
called ‘follicles’ is permeated by a network of capillaries, 
which have exactly the same relation to the indifferent tissue 
in which they are imbedded, as in the Malpighian bodies 
(figs. 9, 10). So far as its structure is concerned, in fact, the 
tonsil exactly represents a lymphatic gland, developed around 
a diverticulum of the pharyngeal mucous membrane; its 
‘ follicles’ precisely resembling the ‘alveoli’ of the latter, in 
being constituted by imperfect septa of rudimentary connec- 
tive tissue, containing a solid mass of indifferent tissue, 
traversed by capillaries. 

Can this series of ‘ vascular glands with false ducts,’ as they 
might be called, be extended by any further addition? I ven- 
ture to think that it may, and that no one can thoroughly 
comprehend the structure of the tonsils without perceiving, at 
once, that there is but a step from them to the liver. A mass 
of indifferent tissue contained in a vascular plexus and ar- 
ranged around a diverticulum of mucous membrane, is a 
definition which would serve as well for the liver as for the 
tonsil ; it is, further, perfectly in accordance with that theory of 
the relation of the biliary ducts to the hepatic substance, which 
is due to Dr. Handfield Jones, and which all recent researches, 
both anatomical and physiological, tend to confirm, viz., that 
the liver is essentially a double organ, consisting of two ele- 
ments, an excretory and a parenchymatous, different homolo- 
gically and functionally. It seems odd that, from being a sort 
of histological and physiological outcasts, the Vascular Glands 
should turn out, if this view be correct, to be the most import- 
ant and extensive class of organs in the whole body, claiming 
the gland par excellence, the liver—as one of their family. 


* TI purposely abstain from including in this series the thyroid and 
pineal glands, because I think it certain that the for mer, and probably, the 
latter, have a different import. 


( 83) 


On the ManuractureE of Larcx AvairaBLe Crystats of 
Surpuate of LIopo-Quintne (Herapathite), for Ovvicar 
Purroses as ArtirictaL TourmauinEs. By Witiram Birp 
Herapatu, M.D., Bristol. 


Havine been repeatedly applied to by various parties for the 
details of my process for the manufacture of these useful crys- 
tals, I have been induced to enter into numerous experiments 
to obtain greater certainty in the results, and to study the con- 
ditions necessary for the production of broad foliaceous plates. 
Permit me to make the formula known to science, together with 
the precautions necessary for adoption to secure the crystals 
when obtained, and to mount them so as to be available as 
polarisers or analysers for the microscope, or even to enable 
us to perform all the experiments in the polariscope. 

The success which I have obtained is so great, that there is 
no doubt tourmalines and Nichol’s prisms will be soon com- 
pletely superseded by these new crystals, since the scarcity of 
the one and the difficulty in manufacturing the others render 
them very costly apparatus. But a little practice in the follow- 
ing process will soon enable any one to make them large 
enough for every purpose ; and so superior are they in power 
to the best tourmaline, that two plates scarcely thicker than gold- 
leaf may (by a slight modification of my formerly published 
method) be rendered totally impervious to light when they are 
crossed at right angles. 

[Herewith are enclosed two marvellously thin plates of con- 
siderable size ; one being six-tenths of an inch long and three- 
tenths of an inch broad, the other the same length but 
one-tenth of an inch broader. Upon crossing them you will 
perceive that they are optically perfect as polarisers, and as 
useful as plates of tourmaline for which you would be charged 
four guineas each plate. I have succeeded in getting much 
larger ones by the same process and equally good.* | 

The materials employed are the same as before, the chief 
modification being in the proportions of the ingredients, and 
the care taken in the method of crystallization. 

It is necessary to procure pure disulphate of quinine, and for 
this purpose none approaches so thoroughly to the standard of 
absolute purity as that manufactnred by Messrs. Howard and 
Kent. 

I dissolve it in pyroligneous acid, having a specific gravity 
of 1:042, and dilute the solution with an equal quantity of 


* We have examined Dr. Herapath’s crystals, and have no hesitation 
in pronouncing them equal to any polarising arrangement we have ever 
employed.—Eps., Mic. Journ. 

G2 


84 ON THE MANUFACTURE OF CRYSTALS OF SULPHATE 


proof-spirit, made by adding rectified spirit of wine, spec. 
grav. 0'837, to equal bulks of distilled water. 

The spirituous solution of iodine is made by dissolving 
40 grains of iodine in 1 fluid ounce of rectified spirit of wine. 

I can, after these explanations, give the formula. 

Take of disulphate of quinine 50 grains, 
pyroligneous acid, 2 fluid ounces, 
proof-spirit, 2 fluid ounces, 
spirituous solution of iodine, 50 drops ; 
eseolee: the disulphate of quinine in the pyroligneous acid 
mixed with the spirit; warm the solution to 130° Fahr., and 
directly add the solution of iodine by drops, agitating the 
mixture from time to time. 

This formula gives to the mother-liquid, after crystallization 
at 52° Fahr., a specific gravity of 0-986, which appears highly 
favourable to the deposition of the majority of the crystalline 
production, and yet allows only the very broad and thinner 
plates to float—thus getting them perfectly free from all inter- 
fering and adhering plates. 

It is necessary to perform this operation in a wide-mouthed 
Florence flask or matrass, and to take care that the temperature 
is maintained for a little time after the addition of the iodine, 
so that the solution should become perfectly clear, dark, 
sherry-wine colour ; then set it aside to crystallize, under the 
following conditions :— 

Ist. It is essential that the apartment should be tolerably 
equable in temperature, about 45° or 50° Fahr., as a slight 
variation in the temperature produces currents in the crystal- 
lizing fluid which destroy the parallelism of the crystals, and 
of course negative all the efficiency of the manufacture ; anda 
greater rise, if only to 60° Fahr., redissolves the thinner plates. 

2nd. It is equally necessary that the liquid should be kept 
in a perfect state of repose during the whole act of crystalliza- 
tion—even the common vibration of the apartment must be 
counteracted, for the same important reason as the last. 

The best method to adopt is one which my friend Mr. 
John Thwaites employs, namely, to suspend the flask by the 
neck with strong twine, and attach this to a similar string 
stretching across from one wall of the apartment to the other. 
This certainly gives the most uniform results, and offers other 
advantages. 

The plan I had usually employed was to set aside the flask 
on the steadiest support to be found, a wall, pillar, or table; 
and imbed it on a feather, cotton, or tow pillow, to act as 
a non-conductor, and at the same time destroy vibration. 

drd. It is also necessary that the surface of the fluid should 


99 39 


OF IODO-QUININE FOR OPTICAL PURPOSES. 85 


not be exposed to too rapid evaporation, as the temperature 
would fall too quickly, and various currents and intestinal mo- 
tions would result; therefore the flask or matrass answers 
better than the evaporating dish. 

4th. It is also decidedly an advantage to have a_ broad 
surface in proportion to the depth of liquid; the reason 
being, that the thinner and most easily reached plates form on 
the surface, and float there until the time arrives to remove 
them ; and the greater the surface, the more numerous are the 
plates. 

5th. These broad plates are not always formed; but if 
after six hours none make their appearance, it is merely neces- 
sary to apply a spirit-lamp to the bottom of the flask and 
warm the liquid to dissolve all the deposited crystals, then add 
a little spirit and a few more drops of iodine solution, and 
again wait for crystallization. 

6th. Supposing that we obtain a crop of these broad floating 
plates, which generally occurs under the aforementioned con- 
ditions, we permit them to remain from twelve to twenty-four 
hours to complete their disc and fill up all crevices, &c., and 
to attain a sufficient degree of thickness; for if too thin, they 
do not stop the red or purple-violet rays, as Haidinger has 
beautifully shown and admirably explained (vide Phil. Mag., 
Oct. 1853, and Poggendorff’s Annalen, for June last). If the 
crystals are allowed to remain too long in their mother-liquid, 
we run the risk of loss and injury ; for after some time a dis- 
solving or disintegrating action appears to occur, and con- 
siderable disappointment is occasioned. I have lost several 
batches of beautiful and magnificent plates from inability 
to secure them at the nick of time. 

Having by these means obtained the object of our best 
Wishes, it now remains to secure the prize. This requires 
a little patience and a tolerable amount of care; the following 
plan is the most ready, and requires but little practice and 
a steady hand to insure success. 

The first stage of the process is to procure a table as near as 
possible to the crystallizing spot, furnished with the following 
apparatus :— 

1, A gallipot or small mortar, to hold the flask on as a support. 

2. A supply of perfectly clean circular glass discs, small 
enough to pass down the neck of the flask with ease. 

3. A glass rod of sufficient length to descend to the bottom 
of the flask, if necessary. 

4. A little marine glue or sealing-wax. 

5. A spirit-lamp and matches. 

6. A quantity of blotting-paper cut in strips about an inch 


86 ON THE MANUFACTURE OF CRYSTALS OF SULPHATE 


wide and two inches long, and also a folded sheet of the same 
to act as a pad or support. 

Now remove the flask with the greatest amount of care from 
its attachment to the horizontal string; this is best done by 
holding the perpendicular twine in the left finger and thumb, 
at the same time cutting the upper end of it with a pair 
of scissors to avoid all disturbance. It will now swing easily 
and steadily, and may be carried and gently deposited upon its 
gallipot support. Then attach the edge of one of the circular 
glass discs to the end of the glass rod by a little of the wax or 
marine glue, and let it, when cold, be carried flatly down the 
neck of the flask, which should be very gently inclined, as 
nearly horizontally as possible, to admit of this’ being easily 
accomplished. Having selected the largest crystalline plate, 
pass the glass circle gently beneath it, raise the plate by 
depressing the hand, and the little crystalline gem is at once 
caught on its surface. 

If this operation be neatly accomplished, it appears spread 
out as a thin uniformly-coloured film upon the glass; if any 
black patches appear, they are occasioned by the accidental 
crossing of some interposed crystals, or from some on the 
under surface of the glass disc. These last must be at once 
wiped off by the blotting-paper, the others will sometimes float 
out upon raising the edge of the glass disc to a perpendicular 
position; if they are near the edge, they may sometimes 
be gently drawn out from under the large crystal by a 
little dexterity on the part of the operator; frequently there 
are no such precautions necessary. 

Now rapidly dry the plate by imbibing all the fluid most 
scrupulously by blotting-paper. This must be done without 
touching the crystalline surface, for the least contact destroys 
its beauty, symmetrical arrangement, and optical usefulness. 
Having done so, let it dry by exposure to the air in a cool 
room, say at 40° to 50°; this is to prevent resolution and 
disintegration of the crystal in its own mother-water, a little of 
which must remain attached after all our care. 

It is sometimes necessary to float them on, or dip them for 
an instant only in a little cold distilled water, somewhat imbued 
with iodine. This serves two purposes; it removes all 
mother-liquid, and prevents crystals of sulphate of quinine 
subsequently forming and interfering with the perfect 
polarization of the new tourmaline, as every crystal of this 
substance interposed between the plates would, of course, 
rotate the polarized beam as far as its influence extended, and 
depolarize it. ‘The iodine acts also in preventing the solution 
of the new crystals in the water. They must again be dried 


OF IODO-QUININE FOR OPTICAL PURPOSES. 87 


by imbibition and by exposure to air, as before, and then 
placed under a cupping-glass, having a watch-glass, with a few 
drops of tincture of iodine in it. This gives adecidedly black 
tone to the field ; and, if the crystal were before too thin to 
obstruct all the light, and thus give a red or purplish violet- 
tint, its power of polarization will be very materially improved 
by following the above simple directions. 

It is essential in iodizing the plate that the exposure to the 
vapour be not too long continued ; the time necessary will, of 
course, depend on the temperature of the apartment; about 
three hours at 50° Fahr., being generally necessary. The 
reason of this precaution will be at once evident upon making 
the experiment, for the crystals assume a rich golden yellow 
colour, both by reflected and transmitted light; the field will, 
therefore, when the two plates are parallel, be intensely yellow, 
a most objectionable colour for the examination of objects. 
The crystals have lost the power of stopping the yellow rays, 
and the complementary relation of the body to the superficial 
colours appears to be lost also—a very remarkable fact. 

The rationale of the periodizing process appears to be 
the addition of as much iodine to the crystal as will be suf- 
ficient to communicate the exact complement of yellow to 
neutralize the red and blue rays of the purple “ body-colour.” 
These rays are now absorbed by the plates as they would be 
by yellow glass.* If too much iodine be added, an intense 
yellow light becomes transmissible when the crystals are 
parallel, and the plate becomes rotten and brittle, and will be 
almost certainly destroyed in mounting, even if it be exposed 
to the air for some time before attempting to do so; by which 
process the superadded iodine again volatilizes, clearly showing 
that no chemical union could have existed. 

Having so far prepared the “ artificial tourmalines,” it 
merely remains to cover them by another plate of thin micro- 
scopic glass, interposing some highly refractive cement or 
varnish between the two plates. 

Several cements offer themselves to our notice, but some 
selection is necessary. Canada balsam is one of the best: 
however, in using this it is necessary to have it very fluid, 
and not to employ much heat in the process ; in fact, I believe 
it best to use it so as to be fluid at the ordinary temperature, 
I have found, however, that it appears to attack the crystals 
and dissolve out the iodine. In order to correct this destruc- 


* T have since found that yellow glass has no effect in absorbing these 
red or violet-red rays—the only absorptive media which I have found 
possess any power in stopping them, are, copper solutions, glass charged 
with copper, or a thin crystal of sulphate of copper. 


88 ON THE MANUFACTURE OF CRYSTALS OF SULPHATE 


tive tendency, it is essential to saturate the fluid Canada 
with iodine, at the ordinary temperature. ‘This is best done 
by warming some small quantity of the balsam in a test-tube 
or thin bottle, and dropping into it some crystals of iodine, 
agitating them well together by a glass rod: giving time to 
cool, and the excess of iodine to subside, it is fit for use. It is 
merely necessary to take a small drop of this fluid on the end 
of a glass rod, place it on the larger and clean glass circular 
disc, then invert thé disc, carrying the crystal upon it, press 
the two together gently and steadily with the finger or a glass 
rod, or piece of stick, taking great care hot to use much force, 
in case the circles or crystal may sustain injury. Now remove 
all the extra Canada balsam from around the edge, and expose 
the little apparatus to the air, so that the balsam may become 
dry; it is then fit to mount in the brasswork of the micro- 
scope in the same manner as a tourmaline, 

I have found it best to employ an ethereal solution of 
Canada balsam in this process, made by dissolving the hard 
old balsam in washed pure sulphuric ether, afterwards adding 
a little iodine to it as before. This dries more rapidly, 
hardens quicker, and move perfectly than the usual fluid 
Canada, and it does not attack the crystals—a very great ad- 
vantage. 

These directions may appear very prolix, tedious, and 
excessively troublesome ; but, however, when set in practice, 
the whole opération resolves itself into the utmost simplicity ; 
habit soon reconciling oneself to the routine, and the different 
precautions appear to offer themselves unconsciously to us as 
we proceed. I have frequently prepared a dozen good tour- 
malines in an hour, as far as the catching and drying part 
of the operation ; the others, of course, require longer time, 
but for these we must wait, and occupy ourselves with some 
other stages of the same process. 

When it is absolutely necessary to obtain a perfectly black 
field with a total stoppage of all the incident rays (upon 
*“‘ crossing’ the two crystals), it is much the better plan to 
employ a thicker plate of this substance: such a crystal will 
be generally found in the flask at the bottom of the mother- 
fluid. There is more trouble requisite in obtaining perfect 
plates, free from all intervening crystals, but the experi- 
menter is generally repaid in the end by the perfection of the 
polarizing medium, 

When the selenite stage is employed, the thinner and violet- 
coloured crystals are far preferable to those which give a black 
tone to the field; as the colours are more brilliant and the 
flood of transmitted light much greater, so that we are enabled 


OF IODO-QUININE FOR OPTICAL PURPOSES. 89 


to use a less illuminating power. I am not in the habit of 
using an achromatic condenser with my polarizing apparatus, 
which probably accounts for some discrepancies in the results 
of observations made by different experimenters upon the 
same crystalline plates: those crystals which will transmit 
the violet rays when strongly illuminated will not do so when 
the instrument is used in daylight, or with a plane instead of a 
concave mirror, and without the achromatic condenser. 

If it be necessary to obtain a most decidedly black field, the 
violet rays may be readily absorbed by interposing a thin 
plate of sulphate of copper beneath the polarizing plate of 
Herapathite and the source of illuminating power. 

The author has recently employed a plate of this substance, 
1-20th of an inch thick, cut on a hone, polished and mounted 
between two plates of thin glass in Canada balsam, as a 
means of correcting the defects of the thinner plates of his 
new tourmalines*—this substance possessing the power of 
absorbing the violet rays of the spectrum in a pre-eminent 
degree. In order to succeed in this experiment it is neces- 
sary that the sulphate of copper should be inclined at a certain 
angle to the plane of primitive polarization, as it is a sub- 
stance possessing two neutral axes or planes of no-depolariz- 
ing power ; the position of which may be easily found, and 
their direction marked upon the support, so that the interven- 
ing plate may be always inserted at the angle of its greatest 
activity. 

Professor Stokes has lately, in a letter to me, suggested the 
employment of a glass Jaden with the oxide of copper as a 
means of attaining the same end : having, therefore, prepared 
a boracic glass, coloured by the black oxide of copper, I have 
used it effectually as an absorbent medium for counteracting 
the violet-red colour of the polarized beam. But although it 
offers great and manifest advantages when the new tourmalines 
are crossed at right angles, yet, upon revolving the superior 
crystal, and therefore bringing the two plates into a parallel 
position, we have a blue colour in the field, which must 
assuredly alter the colours of depolarizing media: it is, how- 
ever, a very agreeable light to work by, as the intense yellow 
of gas-light is much mellowed down and counteracted by it. 
This corrective medium would be inadmissible when the 
selenite stage is employed, as the tints would be materially 
changed by its absorptive agency. 

The mode of making this glass is simply to dry powdered 
biborate of soda in a crucible by the heat of an ordinary fire ; 
again reduce the effloresced mass to powder, and mix it with 


* A solution of the sulphate or nitrate of copper in water will equally 
succeed in producing a black field. 


90 GREGORY ON THE NEW FORMS, &c., 


a small quantity of the oxide of copper, such as is generally 
used in organic analysis, then introduce the mixture into a 
platinum crucible, and with a steady, long-continued heat, 
thoroughly vitrify it, pour it out upon a flat slate, clean 
metallic, or Wedgwood-ware surface, and press it while still 
soft into a flattened plate. Upon cooling, a portion must be 
quickly ground down on a hone, polished, and then mounted 
in Canada balsam between glass: the unmounted boracic glass 
may be kept for any length of time in turpentine without change, 
but in the air it effloresces, and becomes opaque and useless. 

There is not the least doubt that, before long, these splendid 
and useful crystals will be offered for sale by opticians at 
as many shillings as tourmalines now cost pounds, and cer- 
tainly of equal value and practical utility—in my own opinion, 
of even greater, for less light is lost by these than by any of our 
polarizing apparatus at present in use. 

I have invariably used, in this description, the original 
terms employed by me, namely, “ artificial tourmalines,’ ° and 
“¢ crystals of sulphate of iodo-quinine.” Professor Haidinger’s 
term of “ Herapathite” is certainly a highly complimentary 
one to myself; but as it does not give either an idea as to the 
optical properties or chemical characters of the substance in 
question, it does not appear to me so suitable as those I origi- 
nally attached to them. 


. 


Notice of the New Forms and Varieties of Known Forms occur- 
ring in the Diaromacrous Eartu of Muti; with Remarks 
on the Cuiassirication of the Diaromacez. By Wi ii1am 
Grecory, M.D., F.R.S.E., Professor of Chemistry in the 
University of Edinburgh. 


Tue two notices which have already appeared in the Journal 
have made known the occurrences, in this deposit, of about 
ninety distinct forms, of which two were noted as being new 
to science. But the continued and diligent examination of it, 
which I have carried on during my residence abroad last sum- 
mer, has led to results so much more remarkable, that I have 
to beg of the readers of the ‘ Journal’ to regard those papers 
as merely introductory to a more satisfactory and complete 
account of this interesting deposit. This I shall now attempt 
to give; but the limits of this paper, and of the illustrative 
plate, will not allow me to complete it at this time, and a 
large portion of my materials must therefore be reserved for a 
subsequent number of the ‘ Journal.’ 

My observations have been made on a very large number of 


OF THE DIATOMACEOUS EARTH OF MULL. 91 


excellent slides ; and the method of search which I have found 
to answer best is the following, which I briefly notice here, 
because, by a slight alteration in the usual mode of keeping 
notes of what is seen, it is easy afterwards to find any required 
object, by the help of these notes alone :— 

I always begin, then, the examination of a slide at the right- 
hand side, and carry it on by successive vertical sweeps, the 
first and all the odd numbers being downward sweeps (appa- 
rently, really upward), and the even numbers upward ones. I 
find this a great help to the memory. If in the first sweep I 
notice nothing remarkable, it is simply recorded thus | 1 |. 
If I see in it a peculiar or very fine specimen, I note this 
after the number, prefixing certain abbreviated signs to show 
whether it be above, or below, or near the middle horizontal 
line, or near the top or bottom of the sweep. Thus, | 1. Bm, 
P. latestriata 8. V. fine. N b, S. Craticula | signifies that in 
sweep 1, below the middle line (really, not apparently), I find 
a fine S.V. of the new Pinnularia, and near the bottom, a Suri- 
rella Craticula. Having made the first sweep, I now shift to 
the second, and the extent of shift is, as nearly as possible, 
half a diameter of the field. I use for searching, either Ross’s 
1-4th or Smith and Beck’s 1-5th, with the 2nd eye-piece. 
This high power is necessary on account of the numerous 
small forms; of course I note the object-glass used, or by 
means of the draw-tube make the field of the 1-4th equal to 
that of the 1-5th. I go on in this way over the whole slide, 
noting every remarkable form, and as the number of sweeps 
varies, according to the diameter of the cover, from 60 to 80 
and upwards, it is easy to see that the exploration of a full 
slide is a matter of considerable time and labour. But the 
notes, being once made as above recommended, serve not 
only as a record of the remarkable contents of the slide, but as 
a means of finding any object. If the object be in a sweep 
near the right side, say in 4, I make four shifts from the side 
onwards, and move up or down according to the record, and 
am sure to find the object instantly. If it be further on, I 
look for some very conspicuous object, such as a fine P. alpina, 
&e., not far from it (with a low power), and, replacing the 
high power, count the shifts from that; or with the high 
power I take the first striking object in that part of the slide, 
and, referring to the notes, use it as a point of departure. I 
may, however, in every case, count from the beginning or end 
of the sweeps, that is, from the right or left sides of the slide, 
and if the shifts have been well made, the object is always 
very soon found ; and if not, it must be very near, on one side 
or the other, and by trying a little, it is sure to appear. 


92 _ GREGORY ON THE NEW FORMS, &c., 


There is really no more trouble in keeping the notes in the 
above-described way than in any other. But in the case of 
any very remarkable form, which requires further examination, 
I move to the nearest edge of the circle, and note carefully 
any marks there, by which I can find the object in a moment, 
at any time. If there are no marks there, I look on the 
opposite side, or on one of the two other sides, and if 
none have marks naturally, which very rarely happens, I 
place a spot of ink, and note it. In this way my notes 
serve as finders, without the annoyance, incidental to the 
finders recently proposed, of having continually to change the 
object-glass. At the same time, the application of a scale to 
one side of the slide, as recommended in a recent number of 
the ‘ Journal,’ answers well for finding single objects, although 
its use is too troublesome to allow it to be employed in a case 
like the present, where hundreds of forms have to be marked. 

I have just said that the exploration of a single slide de- 
mands both time and labour to no small extent; and I must 
add, that a single exploration, however careful, is never suf- 
ficient. A second or a third will invariably detect interesting 
or even new forms, overlooked on the first, as 1 have very 
often experienced. 

And this leads me to remark, that the results hitherto ob- 
tained from a careful exploration of the Mull deposit have been 
such as to convince me ihat none of the known deposits have 
yet been fully investigated. Indeed, few are willing to devote 
to them the time and labour necessary for this purpose. At 
the suggestion of the Rey. Mr. Smith, therefore, I propose to 
examine all the fossil Diatomaceous deposits I can procure, 
which I the more readily undertake because, being lame, and 
unable to walk far, I cannot attempt the collection, personally, 
of living species. I beg therefore to mention that I shall feel 
extremely grateful to observers for any portions of such de- 
posits, from any part of the world, which they can spare for 
examination ; and that I shall be happy to supply them with 
the Mull deposit, which it will soon, I fear, be impossible to 
obtain in situ, as I understand a great part of it has been 
removed in the course of agricultural improvements, and em- 
ployed as manure. I have, fortunately, sufficient for micro- 
scopical purposes. 

I proceed now, in the first place, to lay before the reader a 
list, corrected to the end of November, 1853, of the known 
forms which I have detected in the Mull deposit. In the 
second place, | shall briefly describe some of the new forms 
which have occurred, leaving the remainder for the next part 
of this paper; and thirdly, I shall notice certain striking 


OF THE DIATOMACEOUS EARTH OF MULL. 93 


varieties of known and figured forms, in which the deposit is 
remarkably rich. I shall conclude with remarks on the classi- 
fication and nomenclature of the Diatomacez, on which sub- 
ject the study of this deposit promises to throw much light. 
As the first volume of the ‘Synopsis’ of the Rev. Mr. Smith 
is, or ought to be, in the hands of every student of the Dia- 
tomacez, I shall adopt the names employed in that work, in 
order to facilitate reference. The ‘Synopsis’ is the only 
work on the subject, so far as I have yet seen, in which the 
figures are really calculated to assist the observer. In 
organisms, such as the Diatomes, in which the markings con- 
stitute essential characters, and in which, also, the number of 
forms having a great general resemblance, and differing only 
in small but important particulars, is very great, nothing short 
of the utmost attainable accuracy in the figures is of the 
smallest value. The attempt to find one’s way through the 
labyrinthine mass of Diatomaceous forms, in the absence of 
actual specimens of all the described forms, by the help of 
the kind of figures often given, is an utterly hopeless one. 
Such figures actually tend to confuse the young observer. 
But the beautiful figures of Mr. T. West, in the ‘ Synopsis,’ 
as I can testify from ample experience, are precisely such as 
the student requires for his guidance. ‘They combine minute 
accuracy in form and markings with a very remarkable and 
very rare quality, that, namely, of presenting to the eye the 
true general aspect or character of the forms, a point of the 
utmost importance, because many species, and even genera, 
are easily recognized by their aspect alone. There is nothing 
at all to be compared to these figures, for practical utility, 
anywhere to be found: on the contrary, in some works, not 
only are the markings inaccurate, or altogether omitted (evi- 
dently because inferior objectives have been used), but the 
character or general aspect of the surface is often so entirely 
missed that the reader fails to recognize forms with which he 
is familiar. Although the ‘ Synopsis ” is not yet completed, 
it fortunately happens that most of the genera occurring in 
the Mull deposit are treated of in the volume already pub- 
lished ; and of course, where I can refer to figures so accurate, 
it is unnecessary to figure the species about to be enumerated. 
I shall only, therefore, give figures of such forms as are new 
or newly distinguished, or such as exhibit important varieties 
not figured in the ‘ Synopsis.’ 

The following is the list of forms observed and identified 
with species figured or to be figured in the ‘ Synopsis,’ and in 
the order of that work. Those marked with a are so abundant 
as to be characteristic of the deposit ; f is attached to such as, 


94 


GREGORY ON THE NEW FORMS, &c., 


although less abundant, are frequent, and occur in every slide ; 
r indicates such as are less frequent, or perhaps rather scarce, 
but may usually be found ; while rr denotes that the form is 
hitherto of extreme rarity in the deposit. 


ike 


eee turgida, f 
f Zebra, r 
Argus, 7 
ocellata, Tr 
rupesttis, 7 
a gibba, f 
ventricosa, Tr 


: Eunotia gracilis, f 


»  triodon, r 

3 tetraodon, a 
>  Diadema, a 
»  bigibbas a 


. Cymbella Ehrenbergii, rr 


e cuspidata, f 


55 affinis, f _ 
5 maculata, a 
- Helvetica, a 


Scotica, a 


: Amphora ovalis, 7 


20. Cocconeis Placentula, Ri 

21 nA flexella (Thwaitesii),f 
22. Coscinodiscus excentricus, rr 
23. Cyclotella Kiitzingiana, f 
24, 8 Rotula, 77 

25. antiqua, 7 

26. Surirella iseriata, f 

27. PD linearis f 

28. a splendida, rr 

29. nobilis, 77 

30. a Craticula, rr 

31. p minuta, 77 

32. ovata, 77 

33, 55 constricta, 77 

34 Brightwellii, 7 


» UB ry: Dlionella mar ginata, 77° 


36. 6 angusta, f 
37. Cymatopleura apiculata, / 
38. e Solea, 77 
39. $5 elliptica, 7 
40. Nitzschia Amphioxys, 7 
41. 3 sigmoidea, 7 
42, = Sigma, 77 

43. 2 linearis, f 

44, 5 minutissima. 
45. Navicula rhomboides, a 
46. 5 serians, @ 

47. ss dicephala, f 
48. > affinis, f 

49. yD ovalis, f 

50 = firma. 7 

bili Fi gibberula, 7 


52. 


ot 


95. 


101. 
102. Himantidium Arcus, @ 


Navicula angustata, 7 
qn obtusa, 77° 
a Semen, rr 
5 Crassinervia, 7 
ss tumida, 77 
= pusilla, 77 
inflata, Tr 
’ Pinnularia major, a 
s viridis, @ 
> acuminata, a 
= oblonga, a 
4 divergens, @ 
as acuta, @ 
of interrupta, @ 


3 Tabellaria, f 
a mesolepta, f 


5 nobilis, f 
»  _gibba, f 

”? lata, f 

» alpina, / 
a radiosa, 7 
= viridula, 7 
a gracilis, 7 


cardinalis, 77r 
stauroneiformis at 
" Stauroneis Phenicenteron, a 


+ gracilis, a 
” anceps, f 
5S dilatata, 77 
x) acuta, 77 
linearis, r 
. Pleurosigma attenuatum, 7 
. Synedra | biceps, a 
E » var, B, recta, f 
5) radians, f 
> Wiper 
capitata, 7 
»  Wancherie, ? r 
delicatissima, Tr 
Cocconema lanceolatum, 7 


“- cymbiforme, f 


7 Cistula, f 
ns parvum, / 
Gomphonema coronatum, a 
#s acuminatum, f 
- tenellum, 7 
PP dichotomum, f 
z capitatum, Si 
4 constrictum, f 
Vibrio, f 


OF THE DIATOMACEOUS EARTH OF MULL. 95 


103. Himantidium majus, a 112. Tabellaria fenestrata, a 
104. 5 pectinale, a 113. > ventricosa, f 
105. e bidens, a 114. a5 flocculosa, f 
106. =A undulatum,a@ | 115. Diatoma vulgare, r 
107. 4 gracile, a | 116. Melosira varians, r 
108. Fragilaria capucina, f aig 3, arenaria, 77 
109. Odontidium Tabellaria, rr | 118. Orthosira nivalis, a 
110. Denticula tenuis (?), 7 | 119. 5 aurichalcea, @ 


111. Tetracyclus lacustris, rv 


The predominance of the forms marked a, and the frequency 
of most of those marked f, give its peculiar character to this 
deposit. Perhaps the group of the Himantidia, all of which 
are most abundant, constitutes the most striking feature. But 
several Pinnularia, the two first-named Navicule, several 
Eunotie, the Tabellarie, the Orthosire, Synedra biceps, and 
Gomphonema coronatum, are all very prominent. Of the 
Pinnularig, P. major is found in very fine specimens and of 
great frequency, but P. divergens (?) is the most abundant, and 
exhibits numerous and interesting varieties. In some portions 
of the earth very fine specimens of P. lata and P. alpina occur 
frequently. Jam not aware that the latter beautiful species, 
which is rare in the living state, has yet been observed in any 
other deposit. Some specimens of it, as well as of P. lata, 
attain to twice the length of those figured in the ‘Synopsis.’ 

Having now noticed those forms which agree with the 
species in the ‘ Synopsis,’ 1 have next to mention those which, 
although known abroad, are not given as British species in 
that work, and such as appear to be altogether new. As most 
of them, so far as they are now to be mentioned, are figured on 
the accompanying plate (Pl. 1V.), perhaps the best way will be 
to notice them briefly in the order in which they occur in the 
plate, being that of the ‘Synopsis.’ I should add, that several 
of the figures are also varieties of forms already mentioned, 

Fig. 1. This is apparently a modification of Epithemia 
Argus, and calls for no special remark. 

Fig. 2. This represents a valve of an Epithemia, not very 
rare in the deposit. It differs both in form, aspect, and 
markings from £. rupestris, when we compare the same 
parts, and I am disposed to refer it to E. gibberula, Ehr., so 
far as I can judge from the separate valves, which have 
not yet occurred united. 120, r. 

Fig. 3. These figures show a few of the forms of Eunotia 
bigibba? which I have introduced into the foregoing list 
because | believe Mr. Smith now admits it as a distinct form. 
It varies most remarkably in length and in the form and pro- 
portions of the dorsal prominences, which in some cases seem 
to be blended into one ; but, in all its variations, the square 


96 GREGORY ON THE NEW FORMS, &c., 


apices are constant, and at once distinguish it from Himanti- 
dium bidens. (P1. IV., fig. 20.) In some individuals, there are 
two ventral as well as two dorsal prominences. (I use the 
terms dorsal and ventral merely to designate the convex and 
concave sides.) 

Fig. 4. These figures represent the new form, which Mr. 
Smith, to whom I pointed it out, has named Hunotia incisa. 
One shows the more frequent, probably the typical form, with 
acute apices ; ; another, the variety £, with rounded apices, 
which is also broader; and a third exhibits an intermediate 
form, with one acute taudl one obtuse apex. All have the 
notches, close to the terminal puncta, from which the spe- 
cific name is taken. The striae are fine, 44 in 001”, and 
require good object-glasses, with careful adjustment, to render 
them visible, especially if in balsam. Those on £, however, 
are more readily seen from its breadth. I find this form, in 
balsam, an excellent test-object for ascertaining the adjustment 
and the general performance of an object-glass. Ross’s 1-4th 
and Smith and Beck’s 1-5th, if duly adjusted, bring out the 
strie perfectly, even without ‘the condenser. I see aiat this 
species resembles in form Himantidium Veneris, Kiitz; but 
the latter, as figured, has no trace of the notches, nor of stria, 
and Professor Kiitzing, to whom I sent a portion of the de- 
posit, regards mine as a new form. This species must be 
added to ‘those above named as being most abundant, and cha- 
racteristic of the deposit. I have detected it in a deposit 
labelled from the banks of the Spey, in that of Lillhaggasén 
in Lapland, and in that of the Liineburg heath; but it has 
not yet been observed in the living state. (I may state here 
that the two last-named deposits, although widely distant in 
locality, exhibit a perfect agreement in the nature and relative 
proportions of the species. I shall take an early opportunity 
of describing a form which I find in both, but of which I can 
see no mention in any work on the subject.) 121, a. 

Fig. 5. The next form is either a Cymbella or a Cocconema, 
these genera, when fossil, being undistinguishable, if indeed 
they are really distinct. It is abundant in the deposit, and the 
reader, on comparing it with the figures of Cymbelle and 
Cocconemata in the ‘Synopsis,’ all of which occur along 
with it, will see that it differs from all. It approaches nearest 
to Cymbella Helvetica, but is much shorter, and also broader, 
in proportion, and is very permanent and uniform in these 
characters. It is possibly a variety of that species, but one 
which certainly ought to be figured. Regarding it, for the 
present, in this light, I shall not give it a separate name. 


122, f. 


OF THE DIATOMACEOUS EARTH OF MULL. 97 


Fig. 6. This is a very remarkable and puzzling form. It 
has the form of a large and broad Navicula serians, with the 
strong median line and large central punctum of that species ; 
but it has also bars resembling those of Surirella craticula (qu. 
canaliculi?), and beneath these fine, but very distinct, cross 
strie. There are also indications of longitudinal lines. This 
strange medley of characters makes it very difficult to class it 
properly. For the present, I shall consider it as Suriredla 
eraticula, with abnormal or sportive development of the 
median line and central punctum, and some variation in form. 

Fig. 7. These three figures represent a Tryblionella, frequent 
in the deposit, which would appear to be a form of T. angusta. 
It is in some cases narrower than the figure given in the 
‘Synopsis,’ and in all these the apices are more acute and 
more produced. It also occurs shorter and broader. There 
are individual specimens still shorter and broader than the left- 
hand figure here given. The striz are very fine, and, I rather 
think, are more numerous than Mr. Smith states them to be in 
T. angusta. 

Fig. 8. This is Navicula affinis, as it occurs in the deposit, 
perhaps nearer the typical form than that figured in the 
‘Synopsis.’ It will be seen that in size, as well as form and 
aspect, it approaches to WV. firma, and should, perhaps, form 
but one species with it. 

Fig. 9. This is a remarkably long and narrow Pinnularia, 
which appears to me distinct from all others, It is of delicate 
aspect and very fragile, has a strongly-developed median line, 
and sides parallel, except just at the apices. The strie are 
radiate in the middle, and distinct. Its form and aspect, as 
well as the much finer striation, and the very delicate margins, 
seem to me to distinguish it from P. acuta; but even if it bea 
variety of that species, it is so marked a one, that it requires 
to be named, I therefore propose for it the provisional name 
of P. tenuis. 123, 

Fig. 10. This is a remarkable small capitate Pinnularia, 
which is perhaps allied to P. mesolepta, but differs from all the 
figures of that species which I have seen. The sides are slightly 
undulated, the striz very delicate, and the rounded heads are 
of almost the same width as the very narrow body, giving it a 
peculiar aspect. It never exceeds, and frequently falls short 
of, the size here shown. (In all the figures the power used is 
400 linear.) I propose to name this form P. undulata. P. 
mesolepta also occurs in the deposit. The present form is 
at once distinguished by its much smaller size, and very 
much finer striation, from the latter, as figured in the 

VOL, II. H 


98 GREGORY, ON THE NEW FORMS, &c., 


‘Synopsis,’ as well as from another somewhat analogous form, 
Navicula nodosa, Kitz. 124, f. 

Fig. 11. This is a small Pinnularia, with very distinct striz. 
There are several forms nearly approaching it, which want of 
space prevents me from figuring at present. This one may be 
supposed to have some relation to P. gibba, but is, certainly, 
not gibbous. The others, which I hope to figure hereafter, 
are still more distinct from P. gibba; and, on the whole, I 
am satisfied that they, or some of them, ought to constitute a 
new species, to which I would give the name of P. parva. 
125, f- 

Fig. 12 represents a very elegant Pinnularia, which is, 
perhaps, allied to P. radiosa; but yet, as may be seen by 
referring to the ‘ Synopsis,’ has a different character, almost 
intermediate between those of P. radiosa and of P. peregrina. 
I figure it, that it may be compared with those in other forms, 
but do not venture to.name it as certainly distinct, 7. 

Fig. 13. This is the new species described by me in the last 
number of the ‘Journal’ as Pinnularia Hebridensis. But 
as Mr. Smith, before seeing my form, found it living at Gras- 
mere in August last, and has named it P. latestriata, I adopt 
his name as the better of the two. It exhibits two varieties: 
one, the type, as I believe, elliptico-lanceolate ; the other more 
linear, and frequently very slightly constricted in the middle, 
as in fig. 13, 6. The coste, 10 to 11 in ‘001", are divergent, 
not reaching the middle line. It is very remarkable that this 
beautiful species should have been detected living so imme- 
diately after I had found it in this deposit, and that, in fact, 
it must have been thus observed by Mr. Smith, even if I had 
not noticed it in the Mull earth, where it is rather scarce. In 
the gathering made by Mr. Smith, at Grasmere (which has 
yielded two other new and beautiful forms), this Pznnularia, so 
long overlooked, is the most frequent of all the Pinnularie 
present. I am informed that it has since been found living 
near. Ipswich, a neighbourhood so well searched that one 
would have thought so marked a form could not have escaped 
notice. These facts strongly confirm what I have above said 
in regard to the necessity of strict exploration, and prove that 
it is not only the fossil deposits, but also the gatherings of 
living forms, which have been imperfectly studied. 126, r. 

Fig. 14. This is a very pretty small form, either a Navicula 
or a Pinnularia, which does not agree with any figures known 
to me. Its form is broadly elliptical, with acute but not pro- 
duced apices. The striz are distinct and radiate. It is, pos- 
sibly, a form of P. gracilis, but differs very much from that 


OF THE DIATOMACEOUS EARTH OF MULL. 99 


species, as figured in the ‘Synopsis,’ or as it occurs in the de- 
posit. It may be called, if new, NV. or P. exigua. 127, r. 

Fig. 15. These figures represent some of the varieties of Pin- 
nularia divergens. Y-ven the typical form, in this deposit, varies 
considerably from that figured in the ‘ Synopsis,’ being sinaller, 
and having about 21 coste in ‘001 instead of 11, as in that 
figure. It farther occurs broad and elliptical, without terminal 
constriction ; with parallel sides, and very narrow, and in many 
cases with a very slight but perceptible constriction in the 
middle. These varieties are seen in the figures, but there are 
many more. I may here mention that the normal form, which 
is not here figured, although in shape and arrangement of 
markings wonderfully close to the figure in the ‘ Synopsis,’ 
yet differs from it so materially in the number of stria, that I 
am led to doubt if it be truly P. divergens. Ifa distinct species, 
then this species will include not only that normal form, and 
the four varieties here figured, but also P. stawroneiformis 
(fig. 16), and, as I have reason to believe from the occurrence 
of forms to be hereafter figured, P. interrupta, W. Sm. also. 

Fig. 16. This figure represents P. stauroneiformis as it often 
appears in our deposit. There are other modifications, which, 
as mentioned in the last paragraph, may have to be united to 
fig. 15. 

Fig. 17. This figure represents a new species of Stauroneis, 
which is not figured in any work I have seen. Its form is 
nearly rectangular, the stauros distinct, not reaching the mar- 
gin, the striz so delicate that it is very difficult to see them. 
I name it S. rectangularis. 128, r. 

Fig. 18. This is a large Gomphonema, which was included 
under G. acuminatum, but appears to have been recently dis- 
tinguished. J cannot ascertain whether this be the form called 
G. Brebissonii ; but as it has not yet been figured, I give it. 
It is supposed by some to be merely the sporangial frustule of 
G. acuminatum. This is a point I am unable to decide. 
129, f. 

Fig. 19. This I consider to be a Gomphonema not yet de- 
scribed. It is so abundant in the deposit as to be one of the 
characteristic forms. It seems to stand between G. tenel/um 
and G. Vibrio; its strie are finer than in most species of Gom- 
phonema. It is possible that it may be a Pinnularia, and with- 
out the F, V., which, as I do not yet know, it is not easy to 
pronounce. But it has so much the aspect of a Gomphonema, 
that I shall consider it as such, and propose for it, in the 
meantime, the name of G. Hebridense, from its abundance in 
the deposit. 130, a. 

Fig. 20. This is one of the forms of Himantidium Arcus, at 

H 2 


100 DIATOMACEOUS EARTH OF MULL. 


least I conjecture it to beso. It is possible, from the character 
of the stria, that it may belong to H. majus. 

Fig. 21. These figures represent several varieties of Himanti- 
dium bidens, in which the two dorsal prominences are seen, as 
the valve lengthens, to sink, and finally to disappear, leaving 
a nearly straight line. But the apices never vary. The 
modifications of this, as of all the Himantidia in the deposit, 
as well as of Kunotia bigibba and Pinnularia divergens, above 
figured, are quite endless. 

Fig. 22. These are remarkable, I believe, sporangial frustules 
of Odontidium tabellaria, B. 

I have now noticed all the figures in this plate ; and, adding 
to the former list such of those now mentioned as are dif- 
ferent, we have in all 130 distinct forms in these two lists. 
But this is not all, for I have not been able to figure or de- 
scribe at this time a considerable number of forms still unde- 
termined, several of which I believe to be new. These must 
be reserved for another occasion. Moreover, I have now to 
mention a few species which I have not introduced hitherto, 
because they are not here figured, and do not occur in the 
‘ Synopsis,’ unless as included under other names. Thus I have 
observed— 

131. Navicula trochus, new to Britain, rr. 

132. Navicula levissima, new to Britain, rr. 

133. Navicula apiculata, one of the new forms lately found 
at Grasmere by Mr. Smith, rr. 

134. Cocconema gibbum, f, new to Britain, at least not in 
the ‘Synopsis.’ 

135. Eunotia Camelus, Kiitz: this, although not in the 
‘ Synopsis,’ [cannot but regard as a distinct form, f. 

136. Eunotia depressa, Kitz: the same remark applies to 
this form as to the last, f. 

137. Himantidium exiquum, Bréb: this is certainly distinct. 

138. Orthosira punctata: this is another new form, observed, 
I believe, living, by Mr. Smith, who showed it to me. I had 
seen it in the deposit, but had neglected it, not having seen 
any good figures of Orthosire, rr. 

I should now proceed to make some remarks on the classifi- 
cation and nomenclature of the Diatomacez, but must post- 
pone these to the next number of the ‘ Journal,’ when I shall also 
describe the remaining forms. Some, I believe, will have to 
be added to each of the divisions of this paper, but chiefly to 
those new as British species, or new to science. I cannot, 
however, conclude without expressing my obligations to Mr. 
West, for the trouble he has taken in producing the very beauti- 
ful figures in the Plate. 


(012) 


TRANSLATIONS, &e. 


On a Substance presenting the Chemical reaction of CELLULOsE, 
found in the Bratn and Sprnat Corp of Man. By Rupoter 
Vircuow. (Sept. 4, 1853.) Virchow’s Archiv. B. VL, 
Hl, p: 139. 


Ir is well known that Carl Schmidt * was the first to discover 
in the Ascidians the presence of a principle previously known 
to exist only in plants, viz. cellulose, and to show that it was a 
constituent of the animal tissue. The researches of Kolliker 
and Léwig,t of Schacht,t and of Huxley,§ have established 
this important fact. The occurrence of this substance, how- 
ever, was limited to a comparatively very low class of the 
Invertebrata, and the further discovery made by Gottlieb, in 
Euglena viridis, viz. that this infusortum contains paramylon, 
a body isomerous with starch, also had reference only to a 
creature in the lowest class of the animal kingdom.|| 
Nothing of the kind, on the other hand, has been known 
as existing in the vertebrata, and it is only since the 
discovery by C. Bernard—that the liver produces sugar—that 
we have had reason to suppose that substances belonging 
to the amylum series may also have a representative. 

From histological considerations, it had struck me that the 
umbilical cord of man presented a great resemblance in 
structure to the cellulose tissue of the Ascidians (Wurzb. 
Verh. 1851. Bd. II., p. 161. note), and I was only the more 
confirmed in this notion by Schacht’s observations, so that 
I have since directed my researches with care to the subject. 
But in many instances this was in vain, as, for instance, in the 
ova of Amphibia and fishes, the remarkable vitelline plates 
of which I described (Zeitsch. f. wiss. Zoologie. 1852. Bd. 
IV., p. 240). 


* ‘Zur Vergleichenden Anat. d. Wirbellos.’ Thiere, 1845, p. 61. 

+ ‘ Ann. d. Sci. Nat.,’ 1846, p. 193. 

~ ‘Mull. Archiv.,’ 1851, p. 176. 

§ ‘Quart. Journ. Micr. 8.,’ vol. i. p. 22, 1853. 

|| The pertinacity with which German naturalists cling to the animal 
nature of Euglena, we must confess, is very surprising to us, who are 
equally satisfied that it is as much a subject of the vegetable kingdom as 
the motile zoospores of any Alga, such as Volvow, Hydrodictyon, Proto- 
coccus, &¢. 


102 VIRCHOW, ON CELLULOSE, FOUND IN THE 


I was more fortunate, when a short time since, I directed my 
attention to the so-termed corpora amylacea of the brain, upon 
the precise nature of which, contrasted with the other kinds of 
amyloid bodies in man, I had not previously arrived at any 
accurate notion. (Wurzb. Verh. 1851. Bd. II., p. 51.) It 
was now apparent that these bodies assumed a_ pale-blue 
tinge upon the application of iodine, and upon the subsequent 
addition of sulphuric acid, presented the beautiful violet 
colour which is known as belonging to cellulose ; and which in 
the present instance appears the more intense from the con- 
trast with the surrounding yellow or brown nitrogenous sub- 
stance. 

I have repeated this experiment so often, and-with so many 
precautions, that I regard the result as quite certain. Not 
only have I instituted comparative researches in different 
human bodies, and in the most various localities, but I have 
also noticed the action of the reagents under all possible 
conditions. The experiment is best made in the mode 
adopted by Mulder and Harting, with regard to vegetable 
cellulose (vide Moleschott ‘ Physiologie isl Stoffwechsels,’ p. 
103), viz., by causing the action of diluted sulphuric acid to 
follow that of a watery solution of iodine. The iodine solu- 
tion should not be too strong, for the observation may then be 
impeded by its precipitation; and, on the other hand, care 
must be taken that the iodine exerts due action upon the sub- 
stance. Owing to the volatility of the iodine, and its great 
affinity for animal substances, its action is usually very un- 
equal, so that the border of the object and not the centre may 
be penetrated by it; or perhaps, of spots in close contiguity, 
one will contain iodine and the other not. It is, consequently, 
always advisable to repeat the application of the iodine 
several times, but to avoid the addition of too much. Upon 
the subsequent addition of sulphuric acid, if the action have 
been too powerful, the result is a perfectly opaque, red-brown 
colour. The most certain results are obtained if the sulphuric 
acid be allowed to act very slowly. In fact, I have procured 
the most beautiful objects in allowing a preparation covered 
with the glass to remain undisturbed with a drop of sulphuric 
acid in contact with the edge of the covering-glass for 12 
to 24 hours. Under these circumstances, the most beautiful 
light violet-blue was occasionally presented. Lastly, I would 
just intimate that accidental mixtures of starch or cellulose may 
readily happen, seeing that very light fibres or minute particles 
from the cloths with which the object and covering-glasses 
have been cleaned, may very easily be left upon them, which 
would afterwards exhibit the same reaction as the above. 


BRAIN AND SPINAL CORD OF MAN, 103 


Every precaution having been taken, the following results 
will be obtained :-— 

1. The corpora amylacea (Purkinje) are chemically different 
from the concentric-spherical corpuscles, of which the brain-sand 
ts composed, and with which they have hitherto usually been 
confounded. The organic matrix of the brain-sand granules 
is obyiously nitrogenous ; it is coloured of a deep yellow, by 
iodine and sulphuric acid. This is true not only of the sabu- 
lous matter in the pineal gland and chorioid plexuses, but also 
of that of the Pacchionian granulations and of the dura mater, 
as well as of the dentate plates in the spinal arachnoid. Inall 
these parts I have, in general, nowhere obtained the blue re- 
action, except in a few spots in the pineal gland. It would, 
therefore, for the future, be convenient to restrict the name of 
* corpora amylacea’ to the bodies containing cellulose. 

2. These bodies exist, so far as I have at present found, 
only in the substance of the ependyma ventriculorum and its 
prolongations. In this I include especially the lining of the 
cerebral ventricles and the transparent substance in the spinal 
cord described by Kolliker, as the substantia grisia centralis 
(Mikrosk. Anat. Bd. II. 1, p. 413). With respect to the 
cerebral ventricles, I have already repeatedly stated, that 
I find them to be lined throughout with a membrane belong- 
ing to the connective tissue class, upon which rests an epithe- 
lium. This membrane contains very fine cellular elements, 
and a matrix sometimes of more dense, sometimes of softer 
consistence, and is continued on the internal aspect without any 
special boundary between the nervous elements. In the deeper 
layers of this membrane, and in immediate contiguity with the 
nerve fibres, the cellulose corpuscles are found most abund- 
antly, and they are also especially numerous where the epen- 
dyma is very thick. They are consequently very abundant on 
the fornix, septum lucidum, and in the stria cornea in the fourth 
ventricle. In the spinal cord, the substance corresponding to 
the ependyma lies in the middle, in the grey substance, in 
the situation where the spinal canal exists in the fetus. It 
there forms evidently a rudiment of the obliterated canal, 
such as it presented in the obliteration of the posterior cornu 
of the lateral ventricle, which is so frequently met with. In 
a transverse section of the cord, it is easily recognised as a 
gelatinous, somewhat resistant substance, which may be 
readily isolated. Its cells are much larger and more perfect 
than those of the cerebral ependyma. This ependyma spinale 
forms a continuous gelatinous filament, which extends to the 
Jilum terminale, and might therefore, perhaps, be most suitably 
described as the central ependymal filament. In it the cellulose 


104 VIRCHOW, ON CELLULOSE, FOUND IN THE 


granules are also found, though, as it would seem, more 
abundantly in the upper than in the lower portion. In other 
situations | have sought for these bodies in vain, and in par- 
ticular | have been unable to find them in the external cortical 
layer of the cerebrum, or anywhere in the interior of the cere- 
bral substance. 

3. Since, from the experiment of Cl. Bernard, who pro- 
duced saccharine urine by wounding the floor of the fourth 
ventricle in the Rabbit, there appeared to be reason to 
conclude that the existence of cellulose was connected with 
that phenomenon, I sought for it also in Rabbits, but in vain: 
I found in that situation both in the fourth, and the third, and 
in the lateral ventricles, a very beautiful tessellated epithelium 
with very long vibratile cilia, but no cellulose. 

4. The cellulose granules, therefore, appear to be every- 
where connected with the existence of the ependyma-substance 
of a certain thickness, and might perhaps be regarded asa 
constituent of it. They occur of excessively minute size, 
so that the nuclei of the ependyma scarcely correspond with 
them. Can they be formed out of the latter? The larger 
they are the more distinctly laminated do they appear. But 
there is never any indication in them of a nitrogenous admix- 
ture, recognizable by a yellow colour. The centre only is 
usually of a darker blue, and consequently perhaps more dense 
than the cortical lamine. 

5. As to an introduction of these bodies from without, such 
a supposition is the less probable because a similar substance 
is nowhere else known. We are acquainted with a series of 
varieties of vegetable cellulose, but the substance now in ques- 
tion appears to be distinguished above all by its slight power 
of resistance to reagents, seeing that concentrated acids and 
alkalies attack it more powerfully than is usually the case 
with the cellulose of plants, 

6. In the child I have as yet sought for it in vain, so that 
like the “ brain-sand,” it appears to arise in a later stage of 
development, and probably may have a certain pathological 
import. 

Since writing the above, Professor Virchow has repeated 
and confirmed his observations, and ascertained in addition 
that similar bodies also occur in the higher nerves of sense. 
He found them most abundantly in the soft grey interstitial 
substance of the olfactory nerve, less frequently in the acoustic, 
although the observations of Meissner (Zeitsch. f. rat. Med., 
N. F., Bd. IIL, pp. 858, 363), would indicate a proportion- 
ately great disposition to their formation in that situation. 
Rokitansky appears to have seen them in the optic nerve, and 


BRAIN AND SPINAL CORD OF MAN. 105 


from an oral communication the author has learned that 
K6lliker has found them in the retina. 

Having already stated that the ependyma is continued with- 
out special limitation among the nervous elements, the author 
goes on to observe that it is now apparent that there is a con- 
tinuous extension of the same substance in the interior of the 
higher nerves of sense. From a series of pathological 
observations, he concludes that a soft matrix referrible mainly 
to connective-tissue substance, everywhere pervades and con- 
nects the nervous elements in the centres, and that the 
ependyma is only a free superficial expansion of it over the 
nervous elements. ‘The opinion, that the epithelium of the 
cerebral ventricles rests immediately upon the nervous 
elements, appears to have arisen from a confusion of this 
interstitial substance with the true nerve-substance. 

The isolation of the corpora amylacea in larger quantity, in 
order that they should be subjected to chemical analysis, the 
author has not yet succeeded in effecting. Nevertheless it 
seems impossible to entertain any doubt as to their cellulose 
nature. No other substance is known which affords the 
same reaction; and although the author has examined the 
most various animal tissues, and has accurately investigated, 
particularly, the concentric corpuscles occurring elsewhere, as 
in the thymus in tumours, &c., nothing of the same kind has 
presented itself.—( Sept. 25, 1853). 

An abstract of the above observations also appears in the 
‘Comptes Rendus,’ for the 26th Sept., 1853, p. 492, but con- 


taining nothing additional. 


Being desirous of verifying the above observations, I 
have examined the brains of one or two individuals ; and, as 
my results differ in some respects from those of Professor 
Virchow, I will here briefly state them, leaving a more 
detailed account of the matter to a future opportunity, 
my observations at present having been too scanty to justify 
the expression of any settled opinion. The first case I exa- 
mined was that of a young man who died of the consecutive 
fever of cholera, after an illness of five or six days, during the 
whole of which period, the renal secretion was completely 
suppressed. What I noticed in this case, was :— 

1. The enormous abundance of the corpora amylacea in cer- 
tain situations, as the ependyma ventriculorum, particularly on 
the septum lucidum, and more especially also on the choroid 
plexuses, upon gently scraping the surface of which a fluid 
was obtained containing these bodies in the most surprising 
quantity. 


106 VIRCHOW, ON CELLULOSE, FOUND IN THE 


2. That they existed in immense abundance in the olfac- 
tory bulbs and in the superficial parts of the brain, both 
cortical and medullary, contiguous to the tract of the olfactory 
nerves. But scarcely any part of the cerebrum and cerebellum 
could be examined, at all events towards the surface, without 
meeting with some or more ; and they occurred abundantly in 
the very middle of the cerebellum. Their distribution, how- 
ever, was very irregular, inasmuch as they abounded in some 
spots and were nearly, if not altogether wanting, in others. I 
could find none in the corpora striata, where they seemed to 
be replaced by “ brain-sand,” of which more will be said 
afterwards. 

3. The cerebral substance, in immediate contiguity with 
the corpora amylacea, appeared quite natural. 

4. The corpuscles were starch and not cellulose, and pos- 
sessed all the structural, chemical, and optical properties of 
starch, as it occurs in plants, as the following few details will 
show :— 

They were of all sizes, from less than a blood-disc up to 
1-500th inch or more—generally more or less ovate, but many 
irregular in outline, and apparently flattened, as all the larger 
kinds of starch I believe are. Many of the larger ones showed 
the appearance which, in starch, has been erroneously described 
as indicative of a laminated structure; whilst in others this 
appearance under any mode of illumination certainly did not 
exist. ‘The point that would correspond with the so-called 
nucleus of a starch-grain was, unlike that of most kinds 
of starch, central, and consequently the laminated marking was 
concentric to the grain, which is rarely the case in the starch 
of plants. This apparent lamination depends, as I believe, 
upon the same circumstances as in other starch (videTrans. Micr. 
Soc., Quart. Journ., vol. i., p. 58), that is to say, upon the corru- 
sation of a thin sacculus. That this was the case I satisfied 
myself by the use of sulphuric acid and of Schultz’ solution 
(chloride of zinc and iodine), in the mode described in my 
paper above quoted. By these means, but more readily and 
conveniently by far by the latter, the corpora amylacea could 
be seen to unfold into empty, flaccid, thin-walled, blue 
sacculi, six to eight times larger than the original grain. 
Their structure thus appearing to be identical with that of 
starch, the identity of their chemical composition was ren- 
dered evident with equal facility. Simple watery solution of 
iodine coloured them deep blue, which ultimately became per- 
fectly black and opaque. They were soluble after swelling 
and expanding in strong sulphuric acid, and by heat; and, 
moreover, they acted upon polarized light in the same way as 


BRAIN AND SPINAL CORD OF MAN. 107 


starch does. Some of the smaller grains exhibited a dis- 
tinct and sharply-defined black cross, of which the lines 
crossed at angles of 45° in the middle of the grain, but in the 
majority, there was only a single dark line in the long 
diameter of the grain, and which seemed always to correspond 
with an irregular fissure or hilus, as it might be termed, in 
the same direction, which was presented in a great many of 
the grains, and seemed to be the indication of a partial inrol- 
ling of them, as in the starch of the horse-chestnut. This 
longitudinal fissure was not unfrequently crossed by a shorter 
one at right angles. When the covering-glass was closely 
pressed, the grains were easily crushed, breaking-up in ra- 
diating cracks around the margin ; and sometimes, when thus 
compressed, a concentric annulation would become evident, 
which was before inapparent. 

In the corpora striata, as I have mentioned above, I could 
find few or no starch-grains, but here an appearance presented 
itself which seems to be connected with their formation. 
Many particles of sabulous matter or crystalline corpuscles of 
the ordinary “ brain-sand,” were met with, all of which, instead 
of lying like the starch-grains, in the midst of unaltered nerve- 
substance, were lodged in irregular masses of what appeared a 
fibrinous or immature connective tissue-substance; and, in 
this instance, upon the addition of iodine, each mass of crystals 
was found to be immediately surrounded by an irregular thick- 
ness of a transparent matter, which was turned not blue, but a 
light purplish pink by that reagent —a substance, in fact, 
closely resembling in that respect the very early condition of 
the cellulose wall; for instance, in Hydrodictyon,—an imma- 
ture form, as it may be termed, of cellulose. 

In a second case, that of an old man—dead of chronic dysen- 
tery, and who died comatose —I found the ventricles distended 
with about three ounces of clear fluid. The surface of the 
ependyma throughout all the continuous cavities was studded 
like shagreen with minute transparent granulations, which on 
microscopic examination, appeared finely granular and homo- 
geneous, or sometimes faintly fibrillated. In this case there 
were, I think, no corpora amylacea in the ependyma (at least I 
found none), nor in the central substance of the brain: a few 
were met with in the peripheral portions, especially on the 
summits of the hemispheres, and still more in the much-deve- 
loped Pacchionian granulations, and there commingled with 
other concentrically-laminated bodies, which formed botryoidal 
masses imbedded in a stroma of immature connective tissue : 
thee bodies, which might, to distinguish them, be termed the 

‘ chaleedonic corpuscles,’ were rendered yellow by iodine. In 


108 ON THE IRRITABILITY OF CILIATED CELLS. 


this case also, I did not notice the quasi cellulose-deposit 
around the particles of ‘ brain-sand,’ but in several instances 
I saw minute amylaceous particles (coloured blue by iodine), 
contained in cells which they only partially occupied.—GeEo. 
Busx. 


Notr.—In the ‘ Comptes Rendus,’ No. 23, (Dec. 5, 1853,) are some further 
observations on the “‘ Animal Substance analogous to Vegetable Cellulose,” 
by R. Virchow, in which he announces the discovery of corpuscles present- 
ing the same reaction’ as the corpora amylacea of the brain, in the Mal- 
pighian corpuscles of diseased human spleens—in the condition termed 
“waxy spleen ” (Wachsmilz). : 


On the Irritability of Ciutarep Crtis. By Rup. Vircuow. 
(Virch. Archiv.) Vol. VI. Part I., p. 183. 1853. 


Amone the many extraordinary circumstances with which the 
phenomenon of ciliary motion is surrounded, it has not been 
the least, that we have scarcely been acquainted with a proper 
excitant of it. Whilst we were able to call the contractile 
substances into activity by mechanical, physical, and chemical 
agencies, the founders of the doctrine of ciliary motion, 
Purkinje and Valentin, could, as regards the cilia, find nothing 
but means to impede or destroy it. And the influence of 
mechanical agitation, the only means by which they had seen 
the failing vibration again become more vigorous, was doubted 
by Sharpey. Can it be said, therefore, that the ciliary sub- 
stance is wholly and entirely ‘different from the other contrac- 
tile substances ? 

A short time since, in examining a human trachea, I chanced 
to hit upon the discovery of a chemical excitant for the cilia. 
Upon the addition of a solution of potass to an object in which 
the ciliary movements, which were at first very lively, had begun 
to slacken, I noticed a renewal of the motion in every part, and 
that it lasted until the parts were destroyed by their solution 
in the caustic menstruum. I have since repeated this experi- 
ment under various conditions, and always with the same re- 
sult. In a trachea from a human body, in which the ciliary 
movements had quite ceased in places, and was universally very 
faint, and in which the ciliated epithelium itself was readily 
destroyed upon the mere addition of water, I was still able 
to recal the phenomenon in great intensity, by the appli- 
cation of the potass-solution, although but for a short time. 
In better preserved and more recent mucous membrane, on 
the other hand, the revival of the motion could be maintained 
for a pretty considerable duration. 

I have usually allowed a microscopic preparation, in which 


ON THE IRRITABILITY OF CILIATED CELLS. 109 


I had ascertained the existence of ciliary motion, to remain in 
contact with water until the motion ceased. Not unfrequently 
I was obliged to wait until large clear drops appeared on the 
surface of the cells between the cilia, which indicated the 
commencement of the splitting up of the contents. Under the 
prolonged action of the potass-solution, isolated cilia would 
first begin, here and there, to exhibit irregular, jerking move- 
ments. By degrees, more and more would begin to move, but 
in such a way that their movements were in opposite direc- 
tions, and showed no correspondence either in direction or 
amount, But gradually the phenomenon acquired more and 
more regularity, force, and uniformity, until at last the rapid, 
rhythmical, sweeping movement of whole series of cells would 
be seen to be restored. 

That we have, in this case, to do with a chemical influence, 
is clear; but that the entire phenomena of the motion cannot 
be the result merely of the corrosive action of the alkali, is 
evident from the perfect correspondence in the course of the 
phenomena with what is seen when the movements are spon- 
taneous. It is only when the action of the potass is too 
powerful and rapid that the excitation is seen to be limited to 
a short, active agitation of the cilia, which is immediately fol- 
lowed by the solution of the substance ; and, in this case, it has 
very much the appearance as if it were the sudden swelling up 
of the substance in conjunction with the consequent undula- 
tion of the fluid which produced the motion. But even in 
such instances as this, it may be satisfactorily shown, by 
comparison with other similar minute corpuscles, that a 
moment of activity exists, in which the contractile substance 
produces a movement independent of the swelling up, and 
of the currents. 

Soda acts in the same way as potass; whilst the effect 
of ammonia, which at once causes chemical decomposition, 
is quite different. Nor havel been able to find any other sub- 
stance having the same effect, although I would by no means 
preclude farther researches, my own inquiries having been too 
restricted to decide the matter. When the long list of 
chemical substances with which Purkinje and Valentin (De phe- 
nomeno gen. et fundam. motis vibratorii continu, Vratisl. 1835, 
pp. 74—76) have unsuccessfully experimented, is surveyed, 
no great hopes certainly can be entertained; and I consider 
myself particularly fortunate in having chanced at once to hit 
upon two substances overlooked by those careful observers. 
Nor indeed can they be justly blamed for this oversight, when 
it is considered that they had tried fifty different reagents, and 
each in six different degrees of concentration. 


110 ON GERMINATION OF THE SPORES OF UREDINEZ. 


No further proof, perhaps, is requisite, to show, that the sub- 
stance of the vibratile cilia, from their irritability, as proved in 
the above-described experiments, approximates the contractile 
substance of the muscles (syntonin, of Lehmann). 


On the Germination of the Spores of the Urepinrx. By M. 
L. B. Turasne. Extracted from the Comptes Rendus. 
Tome xxxv. June 1853. 


Tue author had previously shown that the spores of the 
Uredineew, like the pollen-grains of phanerogamous plants, 
had a variable number of pores, from which afterwards tubular 
filaments arose, apparently analogous to those which are the 
first result of the germination of the spore of a fungus. 

In addition, he has proved that the so-called Mcidiolum 
exanthematum (Unger), may, very probably, be correctly re- 
garded as equivalent to the spermogonia of the other fungi, so 
that in all probability it is not a sexual. According to new 
researches the germinal filaments of the spores do not all 
retain the simple, continuous condition, which was formerly 
assigned to them, and probably do not represent the commence- 
ment of the true mycelium. 

When sown, the spores of cidium Euphorbia sylvestris, 
D. C., did not retain their continuity, but were subdivided into 
four or six unequal-sized cells, by means of transverse septa ; 
there then appeared upon each of these cells, and particularly 
of the upper ones, a lateral short process (spicula), which soon 
supported an obovate and rather oblique tubular process. 
These tubes were the last vegetative effort of the spores; they 
became free (?), and produced only very slender filaments. 
Upon the separation of these bodies, the jointed tube from 
which they arose is emptied, and, like the spores, is destroyed ; 
so that this sacculus or filament represents a sort of promy- 
celium, a vegetation which intervenes between the primary 
spore or fruit, and those lesser follicles which are either 
secondary spores, or rather, perhaps, the only true and actual 
producers of the mycelium. 

The same thing takes place in Puccinia, the spores of which 
are capable of germination while yet upon the parent plant. 
The spores of Puccinia graminis throw out tubes by which 
they lengthened two or three times, divide into cells, and 
again produce reniform spores, which soon germinate. It is 
exactly the same in Phragmidium incrassatum. Link. 


ON GERMINATION OF THE SPORES OF UREDINE®. 111 


The Podisomata, also belonging to the Uredinew, throw out 
from their two-sided fruits (sporidia) as many as eight tubular 
processes, crossing each other in pairs and superimposed one 
upon the other, which invest the fungus with a sort of pile; 
each of these produces several obovate spores, which may be 
collected in vast quantity. 

In several Uredinee (U. Rose suaveolens, Tussilaginis 
crassum), the tubular processes are capable of branching, and 
bear a still closer resemblance to a normal, fungoid mycelium. 

The spermogonia of the Uredinez are highly aromatic. It 
is to them that is due the odour of Uredo suaveolens, &c. 

M. Tulasne has not yet accurately investigated the germi- 
nation of the spores of the Ustilaginew. The elongated cell, 
which proceeds from the spores of Ustilago antherarum, Tal., 
is probably analogous to the secondary spores of Acidium and 
Puccinia. 

In Ustilago receptaculorum, Fr. organs, without doubt analo- 
gous to these secondary spores, are produced from a slightly- 
developed promycelium, consisting only of a few cells, but 
resembling that of Meidium Euphorbia sylvestris, D.C. 


On the Structure and Vital Properties of the ConrrRAcTILE 
SusstancE of the Lowest Anmmats. By Professor Arex. 
Ecker. Abstracted from Siebold and Kolliker’s Zeitsch., 
vol. 1., p. 218, pl. 18. 


TuesE observations relate principally to the nature of the 
substance of which the body of the Hydra viridis is composed, 
but the conclusions are applied also to many other of the 
lower animal forms. It is stated that the entire body of the 
Polype consists of a homogeneous, sometimes clear, sometimes 
granular, soft, extensible, elastic, and contractile substance, 
which is reticulated with clear spaces, containing a more or 
less clear fluid. Ecker denies that cellular structure is found 
in any part of the animal, of which structure Corda and Baum- 
girtner would make it entirely to consist. The three layers 
which are presented in the body and arms of the Hydra, are in 
immediate connexion, and are distinguished: 1. The external— 
by the presence in it of the thread-cells and the greater rare- 
faction of the tissue. 2. The middle—by the green granules 
and a less broken-up tissue: and 3. The innermost layer 
by the brown excretion-granules, and during digestion by 


112 ECKER, ON STRUCTURE OF THE LOWEST ANIMALS. 


various absorbed matters, oil-drops, kc. From this similarity 
in the structure of the three layers, it is probable they are all 
equally contractile; though it is perhaps the middle layer in 
which this property resides in greatest activity. 

This contractile substance above-described, from its want 
of definite form, cannot, according to Ecker, be termed mus- 
cular. It is distributed throughout the whole body, and not 
formed into filaments or fasciculi; nor any more is the sensi- 
tive substance yet ‘collected into nerves, but must be assumed 
to be dispersed through the whole body. ‘The one is always 
most intimately connected with the other, as the investiga- 
tion of all the lower animal forms teaches us. It is not until 
nerves are developed, that even scattered muscles are assigned 
for any given purpose in the economy. Muscles are not 
possible without a connecting nervous system. 

The author then proceeds to show the exact similarity 
between the contractile substance of the Hydra and that of 
other lower animal forms—such as the Infusoria and Rhizo- 
poda. The properties of this substance in its simplest form 
are seen in the Ameeba, the body of which, as is known, 
consists of a perfectly transparent, albumen-like, homogeneous 
substance, in which nothing but a few granules are imbedded, 
and which presents no trace of further organization. ‘This 
substance is in the highest degree extensible and contractile ; 
and from the main mass, are given out, now in one part and 
now in another, perfectly transparent rounded processes, 
which glide over the glass like oil, and are then again merged 
in the central mass. There is no external membrane. In 
the body of the Amoeba there occur, besides the granules, 
clear spaces with fluid contents, which are sometimes un- 
changeable in form, and sometimes exhibit rhythmical con- 
tractions. Exactly the same particulars are exhibited in the 
other Infusoria. 

Thus it is evident that the body of the Infusoria is always 
formed of a sometimes perfectly homogeneous and trans- 
parent, sometimes minutely granular, soft, elastic, and con- 
tractile substance, which is more or less extensively pene- 
trated by spaces containing fluid. This substance was 
termed ‘ sarcode” by Dujardin. Ecker proposes to call it 
*‘ amorphous contractile substance.” The clear spaces are 
termed by Dujardin “ vacuoles.” 

The contractile substance is, according to Dujardin, in- 
soluble in water, though gradually destroyed by it (in dead 
Infusoria); soluble in alkali, though not so readily as albu- 
men; coagulable by alcohol and nitric acid. 


perl AS ste! mo 


ECKER, ON STRUCTURE OF THE LOWEST ANIMALS. 113 


Having satisfied himself of the identity of the contractile 
substance of the Infusoria with that of the Hydra, the author 
goes on to inquire whether the same substance occurs in other 
of the lower animal forms? He believes that Quatrefages 
is in error when he describes muscles in Synhydra and Eleu- 
theria, explaining the appearances noticed by that author, in 
accordance with his own views. Reaching the Anthozoa, 
however, and the Bryozoa (Polyzoa), we find abundantly 
undoubted muscular fibres. In the Rotifera and Tardigrada 
the contractile substance is perfectly homogeneous, soft, 
without the least trace of further organization, and exactly 
like the “ sarcode,” with which it furthermore corresponds in 
the circumstance that in the dying animals it forms “ vacuoles.” 
This substance forms sometimes (as in the Rotifera) at the 
anterior extremity, wart-like, ciliated masses, sometimes in 
the interior (especially evident in the Tardigrada) muscle- 
like strings, of definite and permanent form and arrangement, 
which have been actually described by Ehrenberg and 
Doyere as muscles. But in the definition of a tissue it is 
necessary to consider, not the external form, but its histologi- 
cal relations. A perfectly homogeneous, soft, structureless 
substance cannot be called “ muscle,” without a complete 
change in the idea of the latter, and connecting the term merely 
with contractility. This substance (in the Tardigrada) ap- 
pears to form a well-marked transition from the amorphous 
contractile substance, such as we find in the Hydra, to the 
true muscular substance. 

As in this instance the transition from the ‘‘ amorphous 
to “ formed” contractile substance is shown in different 
animals in an ascending scale, it remains to inquire whether a 
similar transition also takes place in one and the same animal. 
That this is the case would appear to be proved by Dujardin’s 
(‘Observ. au Microscope,’ p. 78, Pl. V., fig. 3, 10, 11) observ- 
ation of the very early appearance of amorphous contractile 
substance or sarcode in the ovum of higher animals. He saw 
in the yolk of the egg of the Zimaz, which has no vitelline 
membrane, that the diaphanous substance, surrounding and 
holding together the vitelline granules, exhibited movements 
exactly like those of Ameceba. 

In the larve of Insects again, even after they have escaped 
from the egg (as, for instance, in Chironomus), the muscles 
consist of a perfectly homogeneous, non-fibrillated, very 
contractile substance, precisely resembling the so-called 
muscles of the Tardigrada, whilst at a later period these 
same muscles exhibit distinct transverse striation. It would 

VOL. II. I 


39 


114 ECKER, ON STRUCTURE OF THE LOWEST ANIMALS. 


appear, therefore, from this and the former observation, that 
the amorphous contractile substance, both in the animal 
kingdom and in separate individuals, gradually passes into the 
** formed,” that is, into muscle. 

Accurate chemical examination of the two forms of con- 
tractile substance is highly desirable ; it may, in passing, be 
observed, that both are hardened by carbonated alkalis. In 
the next place, a comparative history of the development of 
the muscular and of the amorphous contractile substance is 
a necessary requisite; and, lastly, an experimental inquiry 
into their vital properties, particularly into their behaviour 
under galvanic excitement, which would show whether very 
different substances possess the contractile. property, or 
whether this property, with a varying histological condition, 
is not connected with a determinate chemical constitution. 

The following are the forms in which the contractile sub- 
stance is met with :— 

1. A transparent, homogeneous, structureless substance, 
reticulated with clear spaces, contractile in all directions, and 
continuous throughout the whole body, or even constituting 
the greater mass of it; no nervous system. ‘ Amorphous 
Contractile Substance.” (Infusoria; Hydra; Hydroida.) 

2. A transparent, homogeneous, structureless substance, 
non-fibrillated, but divided into isolated, muscle-like portions. 
An appearance of nerves. (Systolida; young Insect larve.) 

3. A substance composed of fibres, and contractile in the 
direction of these fibres. ‘* Formed contractile substance, or 
muscular substance.” 

4. Contractile cells, leaving out of the question the Gre- 
garina and the ciliated cells, the appendages of which are 
contractile, appear to occur only in the embryonic condition. 
(Planaria; Heart-cells of the embryo in Alytes and Sepia; 
Caudal vesicle of the Limax embryo.) 

With respect to the last observation, if the author, by con- 
tractile cell, means a cell with a wall distinct from, and of a 
different material to, its contents, his assertion may be 
correct, except in as far as it applies to certain unicellular 
animals—and which will constitute a large exception. But if 
under the same name the so-termed “ protean cells,” of which, 
in fact, the substance of most, if not all, sponges is mainly . 
composed, he is manifestly greatly in error in limiting their 
occurrence so closely as he does. Similar cells, as has been 
pointed out by Mr. Huxley, abound in the tissues of the 
Meduse (in which are also found distinct striated muscular 
fibres) ; in Hydra itself ; and in many other instances, not only 


ECKER, ON STRUCTURE OF THE LOWEST ANIMALS. 115 


in the lower, but even in the higher animals, for the protean 
changes of form have been observed even in the white cor- 
puscles of the human blood. The zoospores, again, of many 
of the lower Alga may be said to be composed of the same 
protean substance, and many, if not all, of these may be 
regarded as unicellular—applying that term in a general 
sense, and not restricting it merely to those organisms which 
present a distinct wall. These monadiform spores, or gonidia, 
are, in fact, well named by Cohn primordial cells, by which 
he means cells composed wholly of vegetable protoplasm, 
which in its essential nature seems to differ little, if at all, 
from the “ sarcode ” or “* amorphous contractile substance ” of 
the animal kingdom.—G. B.] 


( 116 ) 


REVIEWS. 


ON THE STRUCTURE OF THE MuscuLar Fieri AND THE MUscULARITY 
oF Ciuia. By Dr. Barry. 


Dr. M. Barry’s “dominant idea” is a twin spiral; and, in- 
spired by this perverse and pertinacious spirit, he has again 
presented us with a repetition of his views with respect to the 
structure of the muscular fibre and vibratile cilium, in an 
attempt to assign the ‘ Main cause of discordant views on 
the Structure of the Muscular Fibril,” together with some 
“Further Remarks on the Muscularity of Cilia,” in the 
November number of the ‘ Philosophical Magazine.’ 

The latter paper, it is needless to say, states that every 
cilium is a twin spiral ; and, to confirm this discovery, there is 
a wonderful figure of a cilium from the gill of the common 
Oyster. This monstrous object appears to be partly of the 
nature of plant and partly animal, having roots whereby it 
grows, and the faculty of ‘ spinning-up after threads” ‘ by 
its twisting and untwisting.” It is not, however, very clear 
how this primitive “ jenny” performs this task, nor are the 
threads, as their name would imply, to be regarded as the tail 
of the creature, but rather, if it had one, are they to be consi- 
dered as its lead. 

The paper then proceeds to give a notice of a model in 
lead-wire of the muscular fibril, which Dr. Barry has pre- 
sented to various colleges in this country, and to the Univer- 
sity of Prague, we presume, for the edification of his sole 
disciple, Professor Purkinje. This model, which is intended 
to afford a complete elucidation of the mode of action of 
striped muscular fibre, will doubtless be found extremely 
useful to the venerable Professor, and to any others who may 
hereafter be misled into a belief in the inventor’s doctrine. 
But Dr. Barry has omitted to give a model to explain the 
mode of action in the contraction of unstriped and smooth mus- 
cular fibres, and in that of amorphous contractile substance. 
Professor Purkinje has also been gratified with the presenta- 
tion of the model of a young cilium, and at the same time 
with this information :—“ From analogy, it appears extremely 
probable that the heart arises, in like manner, out of the 
nucleus of a cell, being originally such a double spiral as 
in the cilium aforesaid. If so, the spiral form of the heart 
may be explained by the continued division of what was ori- 
ginally a double spiral fibre.” 


DR. BARRY, ON MUSCULAR FIBRIL. 117 


It is satisfactory to find that Professor Purkinje has not 
kept this information to himself, but had the consideration to 
put it into German for the benefit of his compatriots. How 
they will have received it, it is not very difficult to surmise. 

The former paper of those here cited assigns as the ‘‘ main 
cause of the discordant views” respecting the structure of 
things in general, and especially of muscle, entertained by Dr. 
Barry on the one side and the rest of the world on the other, 
the fact, “‘ that observers, in their endeavours to reach the ulti- 
mate structure of the muscular fibril, have actually gone too 
far. Not content with the examination of the mature fibril, 
they have arrived at what almost defies the microscope—its 
embryo [whose ?], mistaking and delineating for the fibril a 
row of quadrilateral particles, the mere elements thereof; mis- 
taking for the chain, as it were, a row of half-formed links 
destined to compose it.” ‘I cannot,” he very properly goes 
on to say, ‘‘ wonder that in a row of quadrilateral particles no 
one could discern my twin spirals,—” nor, we conceive, can 
any one. He maintains, therefore, in the first place, “‘ that it 
was impossible for them to agree with one another; and 
secondly, as our attention was directed to two different things, 
that it was still less possible for any of them to agree with 
me. Hence, a main cause of discordant views on the “ struc- 
ture of the muscular fibril.” 

This extraordinary declaration requires no comment ; but we 
would remark tlat not only in 1842 did Dr. Barry particu- 
larly recommend muscle from the tail of the very minute Tad- 
pole (4 to 5” long.), and has all along maintained the existence 
and asserted the demonstrability of what he calls a coiled fibre 
in the blood discs (concerning which, see Microscopical 
Journal, Vol. Il., p. 257, 1842), beyond which one need 
scarcely go in search of the phantom ; but actually on the page 
immediately preceding that from which the above assertion is 
taken, he expressly and far more truly says, ‘in order 
thoroughly to understand the structure of this tissue, it is 
essential to see it in its most incipient state, and patiently to 
follow it through every stage, for,’ as he properly observes, 
at that early period its elements are very large.” 

We have no purpose of discussing a question, which ought 
long ago to have been consigned to the limbo of oblivion, and 
notice this paper merely to admonish our readers that they 
must not expect to find in it any additional evidence or reason- 
ing in support of Dr. Barry’s singular views. The reasoning 
being of a character of which the congruity between the two 
quotations above given may serve as a sample; and the facts 
consisting merely of some diagrammatic figures of muscular 


118 DR. BARRY, ON MUSCULAR FIBRIL. 


fibre taken from preparations which had been preserved in 
weak spirit or glycerine for three or four years. The author 
also cites a very curious conclusion at which Dr. Allen Thomp- 
son had arrived, from the inspection of some of the well-known 
thread-cells of an Actinia, viz., ‘‘ that if these double spiral, 
prehensile filaments of the Actinia are contractile, they may 
fairly be used as an argument in favour of Dr. Barry’s views.” 
That is, Dr. A. Thompson is of opinion that the structure (in 
this case altogether mistaken) of one tissue can be employed 
in demonstration of that of another with which it*has no rela- 
tion whatever. 

But, that these unfortunate thread-cells should be brought 
into the argument at all is not a little surprising to us, who 
remember with what triumph they were received in Edin- 
burgh, as an undoubted proof of the correctness of Dr. Barry’s 
views, on the supposition, mirabile dictu ! in that city of natu- 
ralists, that they weré portions of muscular fibre! We were 
promised, at the same time, some specimens to the same effect 
from the Lobster or some other Crustacean, which, however, 
does not as yet appear to have been caught. 


BEITRAGE z0R Myxko.oaie (Contrisutions To Myconocy). By Dr. 
GrorGE Fresenius. First and Second Parts, with 9 Plates. Frank- 
fort, A. M., 1852. (With Plates.) 


Dr. Fresenius commences his work with an expression of 
regret that Mycology has up to the present time been so little 
studied; and he attributes the neglect partly to the unsight- 
liness (unscheinbarkeit) of the objects of the study. We 
think, however, that the charge of unsightliness is one which 
cannot be maintained against fungi in general. The Agaricus 
muscartus, with its brilliant crimson pileus and snowy gills, 
the Agaricus rutilans with a cap of more sober crimson and 
gills of the richest yellow, the Agaricus psittacinus, or Par- 
roquet Agaric, varied as the plumage of the bird after which 
it is named ;—these, and many others which might be men- 
tioned, fairly rival flowers in beauty. In fact, a well-arranged 
group of Agarics, Clavarias, &c., gathered from the first wood 
into which the botanist may wander, would form as pretty a 
decoration for a lady’s boudoir as any bouquet from the green- 
house. Those persons therefore who, without troubling them- 
selves with scientific details and distinctions, look only to the 
external charms of the productions of nature, would find ample 
employment in searching out the beauties of the Fungi. We 
find them assuming the forms of clubs, mitres, bowls, cups, 


FRESENIUS, ON MYCOLOGY. 119 


stars, and even of birds’-nests, and lanterns ;* and their colour 
is as varied as their shapes, and growing as they principally 
do, upon the mouldering remains of other organisms, they seem 
intended, as Mr. Lee has happily expressed it, to deck even 
decay and ruin with beauty. 

To the microscopist the study of the Fungi affords oppor- 
tunities for the use of the highest powers of his instrument, 
and for the exercise of the utmost of his manipulative skill. 
The organs of fructification, even in the largest plants, are so 
minute as to render careful preparation and the aid of a good 
microscope indispensable for their examination, and the struc- 
ture of many of the more minute genera is so imperfectly un- 
derstood, and the opinions of mycologists with regard to them 
so much at variance, that a vast field is open for elucidation 
and discovery. 

With this introductory recommendation of the Fungi, we 
will proceed to notice the contents of the work before us, 
which will be found full of interest. It contains particular 
descriptions, accompanied in most instances by plates of about 
eighty different kinds of Fungi. 

The first genera which the author discusses are Mucor and 
Ascophora. He differs from Link, Wallroth, and others, in 
regarding Ascophora and Mucor distinct, stating that his late 
observations have convinced him of the propriety of their 
being united in one genus, and he thinks there is no real 
ground for considering the genus Rhizopus as distinct either 
from Ascophora or Mucor. He alleges that the construction 
of the sporangium is precisely the same in all three genera, 
and that the mode of its disruption does not, as has been sup- 
posed, distinguish Ascophora from others of the Mucoroidee. 
He has not, however, made any remarks as to the difference 
in the arrangement of the spores. In Rhizopus they are con- 
catenated, which may afford sufficient ground for generic dis- 
tinction. 

Five different species of Botrytis are described and figured 
in this volume, and of these five, three afforda striking instance 
of the diversities of opinion amongst mycologists, to which we 
have referred. Dr. Bonorden, in his “ Handbuch der All- 
gemeinen Mycologie,’? states that he considers the Botrytis 
plebeja of Fresenius to be Botrytis elegans ; Botrytis interrupta, 
Fres. to be Botrytis bicolor, and with regard to the third, 
Botrytis furcata, he is unable to come to any decision. 

The following remarks on the flocci of the Hyphomycetes 


* The Diamphora bicolor, a minute Brazilian fungus, has the appearance 
of two small lanterns attached to a forked branch. 


120 FRESENIUS, ON MYCOLOGY. 


may be usefully extracted. The appearances referred to will 
be familiar to those who have paid any attention to the micro- 
scopic examination of moulds :— 


“‘ In diagnoses and descriptions we often meet with the expression flocei 
cequales, in opposition to flocci strangulati, or with the expression articulé 
alternt constricti, alterni compressit. This characteristic, however, is of 
such frequent occurrence amongst those hyphomycetes which have passed 
their earliest stage of growth, that it is hardly worth mentioning in any 
particular case. The ftocci are almost universally compressed, and they 
are twisted in a manner which gives them a jointed appearance ; they may 
have septa or they may not. In the former case the compressed cells 
stand in regular alternation, one over another, cutting each other at right 
angles,* so that we see the surface of one cell and the edge of the adjoining 
one. In order to observe this appearance, the object must be examined 
dry.” 

We may add here, that all moulds should be examined dry 
in the first instance, as the spores are immediately dispersed by 
contact with water. They should then be moistened in order 
to enable the observer to ascertain the mode of attachment of 
the spores. 

The author ridicules, and as it appears to us with some 
reason, the frequent use by mycologists of the expression, 
“ spore insperse.” He says— 

** What would be thought of a botanist who, in giving the generic 
character of a phenogamous plant, were to say that its seeds, after being 
shed, remain hanging, partly about the stem and partly about the leaves ? 
and yet can it be said that the expression ‘ sporce dein floccis inspersce” im- 
plies anything else ?” 

The Asterosporium (Hoffmanni?), of whicha figure is given 
in this work, is peculiar, from the form of its spores, which 
have four conical rays proceeding from them ; the rays do not 
lie in one plane, but diverge in different directions from the 
middle point of the spore. The author says that the spores 
have been compared to a man-trap. The man-trap, however, 
must have been of foreign construction, as there is no resem- 
blance to the English form of this (now illegal) instrument. 
[It is somewhat singular that Chevallier, in his “ Flore des 
environs de Paris,” took upon himself to deny the existence of 
this plant, and to state that its supposed existence originated 
in an optical delusion ; and yet Dr. Fresenius remarks that it 
does not require the assistance of a modern achromatic micro- 
scope to discern the peculiar formation of the spores. 

We extract the following remarks upon the genus Dis- 
C0SIA I— ; 


* “Tn planes at right angles to one another ” would have been a more 
nearly correct expression, although ‘not mathematically accurate, a com- 
pressed cell not being strictly a plane. 


FRESENIUS, ON MYCOLOGY. 121 


‘* Much confusion has arisen from the circumstance that in the observa- 
tions hitherto made, oil-drops have been mistaken for spores, and spores 
for asct ; thus Libert, in speaking of the genus Diéscosia, talks of ascidia 
fusiformia and sporidia globosa. Corda, who had not examined the plant, 
adopted this diagnosis, and Bonorden has lately attributed to the genus 
the possession of round spores and ase7, and moreover has inaccurately 
united it with Dothidea. It is evident that the whole subject must be re- 
examined, and that it is unsafe to rely upon the early observations.” 


One of the most striking plants described by Dr. Fresenius 
is the Peziza macrocalyx. 'Vhe family of the Pezize is a very 
interesting one. It is so numerous, also, that specimens of one 
kind or another are to be met with in every locality. The 
Peziza virginea, a minute plant, the cup of which is of the 
purest white, and fringed with hairs which are frequently 
tipped with dew-drops, is a most beautiful object under a 
2-inch glass. It is so common, also, that there is no difficulty 
in procuring specimens. The Peziza calycina (pulchella ot 
Greville), which we have frequently met with in the neigh- 
bourhood of London, is also fringed with white hairs, but the 
interior of its cup is of a bright yolk-of-egg yellow. The 
Peziza xanthostigma, forms little golden dots upon fallen 
branches in moist woods, and there are many others too 
numerous to mention of equal beauty. The Peziza macro- 
calyx here described is peculiar from its large size and from 
its mode of growth. It is found in pine-woods, sometimes 
solitary, sometimes in groups of as many as four or five 
together. The cup is buried nearly to its middle in the 
earth. The sporidia, it is said, spring out actively upon the 
plant being shaken. This latter circumstance, however, is 
not peculiar to Peziza macrocalyx, but is common to other 
Pezize. We have seen the sporidia of Peziza macropus 
rising like a white cloud from the surface of the hymenium, 
looking as if some fairy were burning incense in the hollow 
of its beautiful cup. 

At the close of the volume we find some interesting observa- 
tions upon the peculiar red spots which are occasionally seen 
upon articles of food, and which Dr. Fresenius, in common 
with most other observers, considers to be of vegetable origin. 
These spots (called by the Germans Blut im Brode) have been 
the subject of much difference of opinion amongst scientific 
men. Ehrenberg attributes the appearance to an animalcule 
which he calls Monas prodigiosa; Montagne considered the 
spots to be Alga, of the genus Palmella; Dr. Sette, of Padua, 
expressed his opinion that the substance was a fungus, and 
called it by the somewhat unpronounceable name of Zooga- 
lactusa imetropha. 

A late writer in the ‘ Gardener’s Chronicle’ is of opinion 


122 FRESENIUS, ON MYCOLOGY. 


that the matter in dispute is a fungus allied to the yeast 
fungus or Torula cerevisie, as it was formerly called, which 
latter fungal is now supposed to be only a myceloid state of 
the common mould Penicillium glaucum. 

We have lately had an opportunity of examining a fragment 
of bread affected in this manner, which has been kept for several 
years. It has the appearance of having been soaked in plum- 
juice ; and our observations of it under the microscope, so far 
as we have yet been able to carry them, accord in the main 
with those of the author. The latter procured some potatoes 
which were affected with these red spots, and he gives an 
account of his experiments and observations, from which the 
following is an extract :-— 

“T took four boiled potatoes and placed them in a drawer, having pre- 
viously rubbed two of them slightly here and there with the red substance. 
After about twenty-four hours, the two potatoes which had not been 
rubbed, and which had not been in immediate contact with the other two, 
were affected with fresh spots of the red substance, whilst the spots upon 
the two which had been rubbed had increased in extent. ‘The spots 
showed themselves in the form of irregular groups of blocd-red drops of 


different size, which in some places were distinct, and in others had run 
into one another. The individual bodies of which the spots consist are 


mere molecules, their diameter varying from 1-2000th to 1-4000th of a 


line. They are mostly round, occasionally oval, and sometimes slightly 
constricted in the middle by way of preparation for increase by division 
into two small round cells. By far the greater number of them, when 
brought under the microscope in a drop of water, remain at rest; they 
lie close together in large numbers; when they are more dispersed in 
the fluid they have a motion which is not distinguishable from ordinary 
molecular motion. When the drop of water moves they are carried me-: 
chanically over the stage like other molecules, and when this motion 
ceases, they remain at one spot in a sort of quivering state until a fresh 
current carries them in another direction. * * * * 
If the eye is kept carefully upon a part of the stage where the small bodies 
are thinly dispersed, it will be observed that they passively follow the 
current of the water, nor, when the current has become sluggish, or has 
even altogether ceased, are individual bodies ever seen to detach them- 
selves from the group and take a contrary direction, which real monads 
would do with great activity.” 


With this extract we must conclude our notice of this 
interesting book. We strongly recommend such of our 
readers as have good instruments and time at their command 
to turn their attention to the subjects treated of init. We 
can assure them from experience, that they will find the study 
a most engrossing one, and the objects of it not unsightly ; and 
their assistance may render good service to Mycology, by 
helping to dispel some of the mists and clouds which still 
envelope many parts of this most interesting science. 


(°9923° 2) 


BorantcaL LETTERS TO A Frienp. By Dr. F. Uncer. Translated by 

Dr. B. Paun. London, Highley. 
Noruine distinguishes our age more than the tendency that 
exists on the part of those who cultivate Science to diffuse its 
truths as widely and extensively as possible. The age of con- 
servation in science is over, and the dream of those who would 
confine it to our universities, colleges, or royal societies, is for 
ever dispelled. Much as we are indebted for this condition 
of things to the practical sagacity of Englishmen, and can 
boast of a large popular scientific literature in our own lan- 
guage, we have yet to offer a large meed of praise to the pro- 
fessors of science in the German universities, for their attempts 
to teach beyond the limits of their college walls, and to gain 
an audience amongst the hitherto despised Philistines. To 
Humboldt, Liebig, Schleiden, Buff, Moleschott, Schacht, we 
are indebted for treatises tending to diffuse a knowledge of the 
highest truths of science, and to these we may now add the 
name of Unger. These Botanical Letters are an indication of 
the progress of botanical science. Let any one compare the 
manuals and introductions formerly put into the hands of 
students with this volume, and they will see how great has 
been the advancement in correct observation and generaliza- 
tion within the last few years. Instead of the mere dry de- 
tails of the forms of the organs of plants, we are introduced to 
a knowledge of their intimate structure and the laws of their 
developement ; instead of an absurd comparison of plants and 
animals, and rude guesses at the functions of the former from 
a study of those of the latter, we have the physiology of the 
plant, established upon observations made upon its own struc- 
ture alone. ‘To all who have attended to the study of the 
physiology of plants it is known, that the use of the micro- 
scope, and that alone, has produced this change and tended 
to this advancement. ‘The structure of organised bodies and 
their functions can no longer be studied without this instru- 
ment ; and it is only as it is skilfully used that we can expect 
to attain a true knowledge of the laws which govern the ex- 
istence of organised beings. 

In noticing Dr. Unger’s work, we can only refer to the 
more especially microscopical department of his work ; and 
here, as in all others, he has displayed the knowledge of one 
who has faithfully kept up with the progress of science, and 
has a claim to be heard as a teacher. We give two extracts 
as examples of the style and matter of the work. Our first is 
from the history of the developement of the plant. 

** Let us now examine, somewhat more minutely, this production of 


building-stones by the plant. As we have already seen, these building- 
stones of the plant are, properly speaking, not solid homogeneous masses, 


124 UNGER’S BOTANICAL LETTERS TO A FRIEND. 


but variously-shaped membranous utricles, vesicles, etc., filled with soft 
substances and liquids of all kinds. Each vesicle which is employed in the 
building up of the plant is, without exception, formed in the interior of an 
already-existing cell : when its formation is complete, it is al once pushed 
out, and laid in the place which it is destined to occupy. Neither windlass 
nor pulley is requisite ; the whole operation takes place so readily, and, as 
it were, spontaneously, that we may well be astonished that such a thing 
is possible. We will now examine how this is accomplished. 

“« First, the old cell swells up considerably, increases in circumference, 
erows ; but it must be remembered that it is not a mere growth that takes 
place here. As in a pregnant animal, new cells are formed in its body ; 
when these have advanced so far in developement 
as to possess all the organs requisite for their 
independent existence, they are set at liberty ; 
and the mother-cell, which, during. the continuance 
of these processes, not only devotes the whole of its 
contents to the formation of the brood of daughter- 
cells, but likewise suffers a diminution of its mem- 
branous envelope in consequence of the progressive 
enlargement, continues in a kind of dream existence, 
and ‘is at last entirely consumed. Fig. 12 repre- 
sents a remarkably large bag-shaped cell from the 
seed-bud of the biennial (crepis biennis). It is 
situated between parenchymatous cells which do not 
any longer enlarge. This mother-cell contains five 
secondary cells, of which the uppermost is further 
developed than the others. The daughter-cells ori- 
ginate, therefore, altogether at the cost of the 
mother-cells: their existence involves the death of 
the latter. Something very analogous is presented 
in the propagation of certain insects ; the pregnant 
animals gradually increase in size to such an extent 
that they appear more like bladders. All the organs, 
all the functions of the mother, are directed to the 
production of her young, and after their birth there remains scarcely any- 
thing more than a dry, rent membrane. May not, therefore, the forma- 
tion of cells by the plant likewise be termed a generation ? And what else 
is the entire plant formation, with its myriads of cells, than the result of a 
continued generation of its elementary parts ? 

“* After this insight into the progressive developement of the stones, how 
different becomes the aspect of the masonry of the plant perpetually being 
renewed, and, as it were, growing out of itself! Here all kind of analogy 
with architectural operations ceases ; we are unacquainted with any work 
of human hands or human invention which is even in the remotest degree 
similar to the building up of the plant temple. It is an invisible hand 
which inscribes upon its walls words as mysterious as those once written 
in the palace of Belshazzar. Nevertheless, we will follow up the formation 
of the cell still further.” 


The author then proceeds to describe the further develope- 
ment of the cell, and subsequently the tissues which it forms. 
In the concluding chapter he again recurs to the functions of 
the cell, and some of those recondite properties it possesses, 
of the nature of which we have yet but an indistinct notion. 


_ “When the uninjured cell is observed in full operation, as it appears in 
its youth, no difference can yet be detected between its contents and 


——OOOoee 


UNGER’S BOTANICAL LETTERS TO A FRIEND. 125 


boundary ; but in the content itself, there very soon appears a vital centre, 
produced in the form of a tiny vesicle. This leaflet, named nucleus, 
causes, very soon after its first appearance, a remarkable separation of the 
half-liquid contents. A tough, liquid, granular substance, detaches itself 
from the residue, which displays a more watery nature. This, called proto- 
plasm, unites itself as well to the vital centre as to the periphery, and thereby 
binds both together with many radiating, simple, and branching threads. 

“Tt is a charming spectacle to observe in the so-far perfected cell, the 
active flow of this vital sap from the centre to the periphery and back. 

“The most manifold motions, even in the most 
opposite directions, are seen in close proximity in Fig. 37. 
the same thread-currents. All is activity and 
motion in this protoplasm ; uevertheless, the 
remaining part remains motionless, and is only 
here and there drawn into the current of the 
stream. ‘These streams are moved by no pulsat- 
ing veins ; there is no pumping apparatus which 
forces them from the centre of the cell and back 
again. This marvellous substance, this self- 
moving wheel, is a protein substance, consisting 
of the same nitrogenous compound that is present 
in every animal. 

‘* In some instances (but, as far as our experience 
yet extends, only in the lower 
plants,) the developement of 
this protoplasm advances be- 
yond the exterior boundaries. 

“It is not a mere motion of 
the liquid mass which goes on, 
but a developement of half-solid 
thread-like processes, capable of 
performing other motions than 
those of circulation. When 
such cells are set at liberty by 
the opening of the mother-cells 
in which they have been formed, they com- 
mence motions entirely independent of the latter, 
and when they are in water, swim about freely 
in it. 

“ Fig. 37 isa young plant of Vaucheria clavata, 
Agdh, at the period of the ripening of the fruit ; 
that is, when the first 


germ-cell is pushed os D 
out. B is the germ- 5 Si ae 
cell after being de- Pom Se 
tached from the i pi ao 

3 re % 
mother-cell, and float- ue Gl : 
ing freely. The ex- 0 --N) \ ; 
tremely delicateciliate ‘~~ | ie Sard 
processes of the mem- ice 
brane by whose vibra- ra al So 
tions the motion is kine ey. 
effected are shown at Leta 


C, magnified a thou- 
sandfold. They will be seen to be of equal size, and to cover the whole 
surface of the egg-shaped cell. D is a group of young germinating plants 
of the same kind, less highly magnified. 

“The thread-like cilia upon their surface serve at this time the purpose 


126 UNGER’S BOTANICAL LETTERS TO A FRIEND. 


of rudders, in the same way as the cilia and hairs of infusoria. Neither 
the form, the chemical nature, nor the power of contraction, without which 
the ciliate or quivering motion would be inconceivable, distinguish these 
vegetable cells from analogous animal forms, and, to connect them even 
still more closely with the latter, dots of colour present themselves as 
indications of organs sensitive to light. 

“ But this burst of life in the plant-cell is of short duration, and ceases 
in the ciliate swarming cells sooner than in others. After a short time 
these feelers, with which they strive to penetrate further into the exterior 
world than by the roots, are drawn in, the cell again becomes smooth, and 
cellulose is soon depositéd upon its surface, which renders the incarceration 
complete. The vigorous play of motions does indeed continue for a longer 
or shorter period, even under the rigid envelope of the cell-membrane, and 
it is at this time especially that the reproduction of the cell goes on by the 
formation of new vital centres; but this last spark of life is soon extin- 
guished, and the victorious forces of molecular attraction, aflinity, &c. 
reduce the cell gradually within the domain of inorganic nature. 

“¢ Nevertheless, it appears that the manifestation of this vigorous vital 
action is reserved to only a few cells in the body of the plant, although not 
for its entire duration, at least for some time. These are the reproduction 
cells. While all permanent cells are capable of manifesting their higher 
nature only in the motion of their juices, the reproduction cells break 
all the bonds which govern the former, and, even although only for a few 
moments, enter into the most unrestrained activity. 

Fic. 38. “In some series of the vegetable king- 
in a G dom, in which, as we have seen, the duality 
of sex does not appear to be fully deve- 
loped, such reproductive cells become 
swarming cells in other series; the one 
reproduction cell does not acquire such a 
degree of freedom, but the second one 
moves the more unrestrictedly, extended 
lengthways, as spermatozoids, whose mo- 
tions are far from being understood in respect 
to their relation to fructification (fig. 39). 

“A, fig. 38, represents a spermatozoid 
of Asplenium septentrionale, detached from 
the mother-cell in which it was formed, 
and moving rapidly in water by means of 
the ciliw. It is magnified x 1200-fold. B, spermatozoids of Hqwisetum 
arvense, magnified x 500-fold. C, a spermatozoid just escaping from the 
mother-cell.—( W. Hofmeister.y”’ 

From these extracts it will be seen how well Dr. Paul has 
performed his task of translation. The work is illustrated with 
numerous carefully executed woodcuts, and, like the series to 
which it belongs, is cheap and very creditably got up; and 
we know of no better general introduction to the biology of 


plants than these Botanical Letters of Dr. Unger. 


ANATOMISCH-HiIsTOLOGIScHE UNTERSUCHUNGEN UEBER FIscHE UND 
Reprinien. Von Dr. Franz Leypia. (ANaTomican axpd Histono- 
GICAL OBSERVATIONS UPON FisHES AND Reprites. By Dr. Franz 
Leypic), BeRuin, 1858. } 

We have more than once had occasion (‘ Quar. Jour. of 

Micros. Science,’ Nos. [V., V.) to refer to the labours of Dr. 


LEYDIG, ON FISHES AND REPTILES. 127 


Leydig, who has done more than any one, of late years, 
towards extending our knowledge of histology to the lower 
Vertebrata and to the Invertebrata. 

His essays are characterized not only by the accuracy and 
elaborateness of their details, but by their breadth of view and 
the extensive knowledge of Anatomy and Physiology which 
they indicate. We are acquainted with no more important 
contributions to the departments of Zoology with which they 
are concerned than his Memoirs on JLacinularia; on the 
larva of Corethra ; on Argulus ; on the anatomy and develop- 
ment of Paludina ; and on the so-called muciparous organs of 
Fishes, which have appeared in Miiller’s Archiv, and in 
Siebold and KoOlliker’s Zeitschrift, in the course of the last 
five or six years. Of equal value are his ‘ Contributions to 
the Microscopical Anatomy and Development of the Sharks 
and Rays,’* published as a small independent work, in 1852 ; 
followed up in the present year, by that now under notice. 
Dr. Leydig must be a hard, as well as an able worker ; for 
his present effort is more considerable than any which have 
preceded it, and assuredly does not fall below them in scien- 
tific value or interest. 

It is divided into two sections; the first of which treats of 
the histology of the Sturgeon, the second, of that of reptiles 
in general. 

Dr. Leydig’s book requires and deserves careful study, and 
we must be satisfied with drawing attention to a few of the 
chief matters of novelty and interest which it contains. 

Verifying Ecker’s discovery, that the pituitary body of 
fishes is a vascular gland, he finds that in the Sturgeon, the 
pineal gland is of a similar nature, resembling the thyroid, 
however, rather than the other vascular glands. 

As might have been expected, from the zoological position 
of the Accipenserida, the ‘ muciferous’ tubes and ampulle of 
the Sturgeon, are intermediate in structure between the corre- 
sponding organs of cartilaginous and osseous fishes. 

A new light is thrown upon the nature of the supra-renal 
capsules by Leydig’s discovery, that in Sturgeons, and other car- 
tilaginous fishes, Batrachia, and Reptilia, they belong to one 
series of organs with the so-called ‘ axillary hearts ;’ with 
certain peculiar appendages, discovered by Leydig, upon the 
ganglion of the sympathetic ; and with the fatty-looking yellow 
bodies on the blood-vessels and in the kidneys themselves. 

In Plagiostomes, in Chimera, and in the Sturgeon, the net- 


* “ Beitrage zur Mikroskopischen Anatomie und Entwickelungsge- 
schichte der Rochen und Haie.’ Leipzig, 1852. 


128 LEYDIG, ON FISHES AND REPTILES. 


works of the hepatic cells lie within canalicular cavities in a 
kind of connective tissue, by which they are supported. 
Leydig considers this to be evidence that the liver essentially 
resembles other glands; a conclusion to which, however, the 
evidence he adduces would not lead us. 

The author’s investigations into the structure of the spleen 
of fishes and reptiles are of the highest importance: they 
fully confirm Remak’s views, and tend to the conclusion that 
the difference between a spleen, a Peyer’s patch, and a lym- 
phatic gland, is but one of degree; while they greatly extend 
our knowledge of the relations between the blood, vascular, and 
lymphatic systems. 

The position and anatomical characters of the Thymus and 
Thyroid glands are determined for fishes and many reptiles. 
Histologically they invariably present the same differences as 
in man. 

Leydig doubts the existence of cecal terminations in the 
tubuli urinifer? of fishes. His inquiries into the development 
of the genito-urinary system of Amphibia and reptiles are of 
the utmost value, and tend to clear up many difficulties in the 
morphology of these organs, not only in these but in the 
higher Vertebrata. 

Our space prevents us from further analyzing Dr. Leydig’s 
work ; but we trus twe have said sufficient to justify the high 
opinion of its merits which we have expressed. 


Der Baum. StTupIEN uBER BAu unD LEBEN DER HOHEREN GEWACHSE. 

Von Dr. H. Scnacut. Berlin, 1853. 
We have already noticed Dr. Schacht’s previous works on the 
microscope as applied to botanical subjects, and his more im- 
portant one upon the Plant-cell—and have again the pleasing 
task of directing our readers’ attention to another from his 
indefatigable pen—which, like the former, contains a vast 
amount of matter interesting especially to the microscopic 
observer. 

Like the previous works by the same writer, the present is 
the result in great measure of independent research, and is 
therefore the more interesting and useful, and contains the 
results of valuable investigations which were made during a 
prolonged residence in the forests of Thuringia. 

It gives a considerable series of detailed, recent inquiries 
respecting the germination and growth of Forest trees, the 
anatomical conditions of the wood, the formation of cork and 
bark, on the structure and growth of the leaves and roots, on 
the formation of branches and of the buds, and lastly, on that 
of the blossom and fruit of most of our common useful trees. 


~~ a 


( 129 ) 


NOTES AND CORRESPONDENCE. 


, ye LE SSI R Se oe eh 


On the best Form of Micrometer for the Microscope. — In 
the ‘Journal’ for October last, page 51, is a paper signed 
H.C. K., on the best form of Micrometer for the Microscope, 
in which Mr. Quekett and myself are said to have disparaged 
the use of the cobweb micrometer in advocating that of ruled 
glass. As Mr. Quekett’s time is fully occupied, perhaps you 
will allow me to make a few remarks. The author is correct 
in saying that, ‘‘ as faras regards manipulation, one form of mi- 
crometer is just as simple as the other,” but the statement 
that 1-1000th of an inch is a common amount of error in the 
ruled glass can only be explained by supposing that the 
printer has omitted a cipher in the denominator of the frac- 
tion ; for the mean of nine observations on such glasses could 
at best only reduce the error to 1-9000th of an inch—a quan- 
tity wholly inconsistent with the accuracy which he advo- 
cates. ‘The error in a carefully-ruled glass rarely amounts to 
1-10,000th of an inch, and therefore the plan of finding the 
value of the cobweb micrometer by a mean of several observa- 
tions will give a sufficiently near approach to absolute ac- 
curacy ; but it does not seem to strike H. C. K. that the same 
means are equally applicable to the glass micrometer when 
placed in the eye-piece. 

In stating that 1-800,000th of an inch can be read by 
a cobweb micrometer and a 1-8th object glass, I assumed that 
the eye-piece was of Ramsden’s form, that the screw had 100 
threads in an inch, the divided head 100 divisions, and that 
the body of the microscope was 10 inches long. Messrs. 
Powell and Lealand I believe use a negative eye-piece and a 
shorter body, and they may probably have adopted a coarser 
screw, but the reading still appears to exceed the power of 
observation four times, and justifies the assertion that the 
readings (not the measurements) of such an instrument are 
** unnecessarily fine.” 

The finest eye-piece micrometer that I use is ruled to the 
1-250, and with the 1-12th object-glass reads 30-1000ths 
of an inch. Now, as one-third of a division is easily esti- 
mated, the power of reading approaches very near to the limit 
of observation ascertained “by H. C.K. Let us suppose that 
an error of 1-1000th of an inch, or one-fourth of a division (an 
amount that should never be tolerated), exists in such a micro- 

VOL, II. Kk 


130 MEMORANDA. 


meter, it will only affect the measurements made with the 
1-12th object-glass to the 1-120,000th of an inch—a quantity 
scarcely appreciable, and much less than the errors which are 
unavoidable in determining the value of the readings, even 
when a mean of more than nine observations is taken.—H. C. K. 
seems to have forgotten that, when a micrometer is applied to 
the magnified image in the eye-piece, its errors are diminished 
in proportion to the amplification effected by the object- 
glass. 

The inquiries for a cheap form of microscope, which I con- 
stantly hear, make me think that the ‘difference between 4/. 
and 17. for an adjunct to the instrument, would in many 
instances be a serious obstacle to the use of any means of 
minute measurement; and it is with the view of placing these 
means within the reach of all observers that I have advocated 
ruled glass. I cannot admit that I have disparaged the more 
expensive instrument, having merely asserted that the meh 
ings obtained by it are far beyond the power of observing 
and that, therefore, it is not so very superior to the trad 
form as a appears to be. Its superiority consists principally 
in this—that there is nothing between the object-glass and 
eye-piece to injure the definition; whereas the ruled glass 
produces a perceptible (though very slight) deterioration in 
the sharpness of the image, and therefore to that extent dimi- 
nishes the accuracy of observation. 

To induce observers to make accurate measurements, 
which is the aim both of H.C. K. and myself, it is not 
sufficient to place an instrument in their hands, they must be 
taught to use it with little trouble. The following directions, 
which are applicable to every form of eye-piece micrometer, 
will tend to promote that object. 

Having screwed on an object-glass, lay a micrometer on the 
stage, and get a distinct view of it. Apply the eye-piece 
micrometer; and taking the divisions on the stage, which 
occupy the middle third of the field, draw out the draw-tube 
until the corresponding reading in the eye-piece amounts to 
some convenient decimal number, or at least can be readily 
translated into one by a simple mental process, such as multi- 
plying or dividing by a single figure. Then examine the 
divisions on different parts of the stage micrometer, and if you 
please, on different micrometers. Should they be found to 
differ, which they probably will in a trifling degree, adjust the 
draw-tube on that part of the scale which gives the mean 
value. The draw-tube being graduated, the point at which it 
now stands, with the reading indicated, should be entered on 
a card in a line with the object-glass used. 


MEMORANDA. 131 


If the fine focal adjustment moves only the object-glass, as 
is usually the case, it should be placed about midway during 
this operation, that its subsequent movements may have as 
little effect as possible in altering the reading. 

The adjustment for the thickness of covering glass, which 
all objectives of large aperture must have, changes the value 
of the eye-piece micrometer so much that it requires a special 
provision. The method which I adopt is to adjust the draw- 
tube in two positions—one when the object-glass is arranged 
for an uncovered object, and the other when screwed to 
the full extent of its motion. ‘These two positions of the 
draw-tube being entered on the card, it is easy to set it so as 
to correspond with any intermediate point that the lens may 
be adjusted to. 

When this has been done for each object-glass, the opera- 
tion of measuring is an exceedingly simple one. Draw out 
the tube to the point corresponding to the object-glass in use, 
and the measurements are at once obtained in decimals of an 
inch, without the trouble of referring to a table of values. By 
this means the micrometer above mentioned (250 in the inch), 
when inserted into a negative eye-piece, is made to read 
5000 with the 4-10, 10,000 with the 1-4, 20,000 with the 
1-8, and 30,000 with the 1-12th object-glasses. By merely 
multiplying the first of these numbers by two, and dividing 
the third and fourth by two and three respectively, the mea- 
surements are at once set down in decimal fractions. —Grorce 
JACKSON. 


Strnctmre of Anacharis alsinastrum.— [n the last Number of 
the ‘ Microscopical Journal,’ appeared an interesting account 
of the rotation in the cells of the new water-weed—Anacharis 
alsinastrum. Mr. Lawson there pointed out the particular 
cells in which the current may readily be seen, viz., the 
elongated cells around the margin of the leaf and those of the 
midrib. On examining the leaf with polarized light, these 
cells, and these alone, are found to contain a large proportion 
' of silica, and present a very interesting appearance. A bright 
band of ‘light encircles the leaf and traverses its centre. The 
teeth-cells at the edge of the leaf do not contain silica, but are 
firmly planted upon the silica band : this evidently gives great 
support to their clinging property. In fact the leaf is set as it 
were in a framework of silica. 

As the silica is only found in the cells in which rotation is 
visible, may not its deposition be in some way connected with 
the circulatory movement? The large amount of silica will 
account also for the brittleness and weight of the plant, which 


x. 2 


132 MEMORANDA. 


sinks to the bottom of the water on being cut, and does not 
float like other water-weeds. The large proportion of silica 
may also render ‘ the pest,” a useful manure for some kinds 
of land. 

The specimen sent with this communication has been 
boiled for a few minutes in equal parts of nitric acid and 
water: by this means a portion of the vegetable tissue has 
been got rid of, and the silica rendered more distinct, without 
at the same time destroying the form of the leaf.—FERa@usoN 


Branson, MD., Sheffield. 


Rotation in Anacharis.—In an extract given in the ‘ Micro- 
scopical Journal’ (vol. il. pp. 54, 55), from my paper in the 
‘Scottish Florist,’ on the ‘* Rotation of the Cell-sap in 
Plants,” a remark occurs which may be inexplicable to your 
readers. In describing the movements seen in the cells of 
Anacharis alsinastrum, it is stated, ‘‘ The arrows show the di- 
rection of motion.” -1 do not suppose that any reader of the 
Journal will be so inexperienced as to look for arrows in the 
plant’s cells; but it may be as well to mention that the remark 
applied to a wood-cut which appeared in the ‘ Florist,’ but 
was not repeated in the ‘ Microscopical Journal.’ I may also 
take this opportunity to add to the observations quoted, that 
while nuclei are generally found in the cells of Vallisneria 
and Chara, which exhibit rotation (and in Chara the nucleus 
is also in motion), there are no nuclei to be seen in the cells 
of Anacharis, at least 1 have not met with any.—G. Lawson, 


7, Hill Square, Edinburgh. 


Binocular Microscope. — Since the publication of the last 
‘ Journal’ which contains the papers of Professor Riddell and 
myself on the ‘ Binocular Microscope,’ I have received so 
many inquiries relating to this instrument that I feel myself 
called upon to make some further remarks on the subject, as I 
find that many are under an erroneous impression of its utility 
and effectiveness. 

At the request of some members of the Council of the 
Microscopical Society, I was induced to bring forward the sub- 
stance of my experiments, and at the time my paper was read 
these were still in progress; for this reason, such information 
as related to the effects of the instrument was somewhat inde- 
finitely expressed, and allowed different observers to form 
their own judgment of its merits. This has tended to some 
extent to place the matter in a false position, which has 
no doubt been confirmed by the rather glowing account which 
the American Professor gives of the performance of his micro- 
scope in page 23 of the last Journal, and the description of 


MEMORANDA, 133 


the formidable aspect that our innocent wheel animalcule 
bears when viewed by his own instrument. 

The binocular microscopes up to the present time have 
done but little else than afford a glimpse of the splendid and 
substantial appearance that nearly all microscopic objects may 
be expected to bear when the instrument is brought near to a 
state of perfection; but this remains to be effected, for all the 
attempts that have been made have failed in giving that 
degree of definition and distinctness which can alone satisfy 
the eye of a microscopist. This arises from reasons that I 
shall now briefly enter into :— 

First, as regards a system of prisms for bisecting the 
emergent pencil close behind the objective: in every way 
that this has hitherto been carried out, the object is seen with 
only half the object-glass, and therefore the undue prepon- 
derance of oblique pencils thus obtained in the formation of 
each image is the cause of very unsatisfactory vision even of 
the easiest tests. If the minutie of structure cannot be seen 
with each eye separately, they will not be rendered visible by 
using them both together. 

When the principle of the dividing prisms is directly 
followed, some improvement may be expected by using 
object-glasses which will give an equally-distinct image, with 
every portion of their acting surface. I believe the construc- 
tion of such objectives to be within the pale of possibilities, 
as I have tried some (by traversing a small stop over the back 
lens) which approach near to the desired standard. Such a 
glass would also be of a superior quality for all the general 
purposes of observation. Where two prisms are employed for 
dividing the pencil behind the object-glass, some of the most 
valuable portion of the surface of the latter, straight across the 
diameter, is lost at the junction of the prisms. M. Nachet 
has most ingeniously remedied this defect, by using only one 
isosceles prism for splitting the pencil in both his binocular 
and duplex microscope. 

If, instead of equally dividing the diameter of the object- 
glass, we can obtain a further portion past the centre both 
ways, or say two-thirds of the diameter in each eye, we should 
still have stereoscopic vision combined with greatly improved 
definition, for the objective would bear to lose the one-third 
portion without materially injuring its defining power. I have 
not yet discovered any optical contrivance that will effectually 
accomplish this: it appears to be almost a mathematical im- 
possibility, 

If a modification of the double-image prism were to be 
placed close behind the object-glass, having a sufficient sepa- 


134 MEMORANDA. 


rating power to bring the object into each eye, both images 
would be alike and would consequently produce binocular but 
not stereoscopic vision; but the latter might be obtained by 
cutting off some portion of the opposed sities of the separated 
pencils : I think that this experiment is worthy of a trial. I 
also believe that the loss of light arising from double re- 
fraction might be supplied by increased intensity of illu- 
mination. 

I am convinced that a perfect result can never be obtained 
by bisecting the pencil behind the object-glass, unless it is 
improved in the way that I have above referred to. On the 
other hand half of the top lens of the eye- piece may be cut off 
without losing sight of the markings on test objects, or other- 
wise materially j injuring the definition; but the greatest objec- 
tion to separating the images there, is the contraction of the 
field, which is caused by reasons I have explained in my 
paper.* I am now seeking a remedy for this evil with some 
prospect of success. | have abandoned all attempts at 
making a binocular microscope with two objectives, as I 
found that I could not get even a pair of 14s to bear upon 
the object together. 

Having now stated distinctly ‘that the binocular microscope 
is at present far from being a perfect thing, and in what diree- 
tion greater perfection is to be sought for, I trust that others 
will fal their ingenuity in effecting improvements; for even as 
it now is, all must agree, on seeing the magnificent perspec- 
tive of some objects (par ticularly living and infusorial) that is 
obtained through its means, that no efforts should be spared in 
attempting to improve it. In this country I have worked at it 
almost single-handed, and have found the subject teeming with 
practical difficulties to an unusual extent; for which reason I 
think it is of importance that the instrument should be 
benefited by the ideas of others, in particulars of construc- 
tion wherein I may have been found deficient.—F. H. 
WENHAM. 


Gn Measuring the Aperture of Object-glasses; and Remarks on 
their Adjustment.— [he usual method of measuring the angle of 
aperture of object-glasses, suggested by Mr. Lister, and 
figured and described in Quekett’s ‘ Treatise on the Micro- 
scope,’ is sufficiently accurate for all apertures up to 100° or 
thereabouts, and I think for general usefulness cannot be 
superseded ; but within the last few years the aperture of our 
highest powers has been increased to such an extent as to 


* See ‘ Quart. Journal of Micros, Science,’ for Oct. 1858, p. 9. 


* 


MEMORANDA. 135 


render their measurement by means of this instrument in some 
respects unsatisfactory. I have therefore to propose an addi- 
tion which will enable us to obtain a more definite result. 

On measuring an object-glass of very large aperture (say 
170°) by the usual method, the extreme light becomes very 
faint, and disappears so gradually as to render it difficult 
to define the boundary between light and darkness, and 
any interior reflection from the rim of the stop, &c., may 
readily be mistaken for aperture. I have now before mea 
1-12th in which light appears visible up to near 180° when 
measured by the ordinary means. In this glass every precau- 
tion has been taken to prevent internal glare: it is provided 
with two stops, and the whole of the inside of the tube black- 
ened with smut lacquer; yet with this object-glass I can see 
through moderately thin glass. As it would be impossible to 
accomplish this with such an aperture, I consider it is a suffi- 
cient proof that there is something radically wrong in the 
method of measurement. 

It occurred to me that it would be preferable to obtain 
a distinct image of a distant object through the microscope, 
and then to rotate it horizontally (taking the focus of the ob- 
Ject-glass as the centre of motion), and stopping at the point 
when the object appears bisected, or half of it, is observed at 
both extremes, the range passed through will represent the 
angle of aperture. This will also have the advantage of show- 
ing the state of correction of the oblique pencils, by the degree 
of distortion appearing in the object, when seen at the exterior 
of the pencil of rays. 

By the mode of measurement hitherto practised, the extreme 
light may appear sufficiently strong; but there is no means of 
judging at the same time whether this is consistent with 
a definite image or is really indicative of effective or well-cor- 
rected aperture. 

There are several optical contrivances which would give an 
image of distant objects through the object-glass, but I have 
preferred the one here to be described because it does not in- 
terfere with the instrument commonly used. It consists 
simply of a biconvex lens of about one-quarter of an inch 
focus, set in a tube made to fit over the top of the lowest 
power Huygenian eye-piece, in a similar manner to that 
which Mr. Ross supplies with his microscopes, under the 
name of an examining-glass. The single lens should be in 
such a position that its focus is coincident with that of 
the emergent pencil from the eye-piece. As the focal distance 
of the latter will vary with every different power of object- 


136 MEMORANDA, 


glass employed, and also with the distance of the object, the 
single lens must have a sliding adjustment. 

Having fixed the single lens over the eye-piece of the ordi- 
nary instrument for measuring apertures, with the object-glass 
to be tried, attached, place a candle in front in the direction of 
the axis of the tube at the same level, and at a distance vary- 
ing from three inches to as many feet, according to the power 
of the object-glass employed, the highest requiring the candle 
to be very close, in order that the image may be of a sufficient 
size to be readily seen; next adjust the single lens by means 
of the sliding tube till the flame of the candle is most 
distinctly visible, then set the instrument at zero, and move it 
bodily round till the wick or centre of the flame is exactly bi- 
sected, and when this occurs again, on moving the index alone 
in the opposite direction the number of degrees passed through 
will indicate the aperture. If the object-glass is a good one, 
the image of the flame when seen at the extremes of the aper- 
ture suffers a remarkably small degree of distortion; but 
when this appears considerable, I have ascertained by direct 
experiment that the performance of the glass is improved by 
reducing the diameter of the stop, and so cutting off the 
exterior or unsuitable rays. I think that it will be easy 
to judge what portion of these are serviceable in assisting the 
definition, merely by the appearance of the flame at the 
extremes. 

With this*method of testing aperture, it is not absolutely 
necessary to be possessed of a special instrument for the pur- 
pose ; for if the single lens is fitted over the lowest eye-piece 
of the ordinary microscope, and two candles be placed in 
front of the object-glass, and moved asunder till the half of 
each flame is cut off, a line drawn from the focal point to the 
centre of each flame will represent the angle of aperture. 
The axis of the microscope and the two flames should be in 
the same plane. 

It is perhaps not generally known, that the position of the 
glasses for adjustment makes a considerable difference in the 
aperture (sometimes to the extent of 15° or more), this being 
always at a minimum when at the mark “ uncovered.” This 
fact should of course be remembered in measuring apertures. 
The 1-2nd and 1-4th may be placed midway between the two 
ranges, but the 1-8th and 1-12th should be taken when at the 
mark ‘ covered,” as we most generally use them when near to 
this point. 

I have only lately used this method of testing the aperture 
of object-glasses, and therefore do not pretend to say that a 


MEMORANDA. 137 


better may not be found; but I have for a long time been of 
opinion that the ordinary mode is insufficient, and trust that 
some attention will be given to the subject.* 


There is one very important point which I have seen almost 
totally neglected by some of the most experienced observers— 
I refer to the adjustment of the object-glass for the aberrations 
caused by the various thicknesses of glass used for covering 
different objects ; for in order to obtain correct definition it is 
quite as necessary that this should be attended to as the focus- 
sing of the objective itself, and, unless performed with 
particular nicety, the late improvements that have been made 
in the way of increasing the aperture will be rendered worse 
than useless, not only in the highest powers but in the lower 
also. For instance, I have a very fine 4-10th, made by Smith 
and Beck, with a working aperture of 90°, which will not 
well show the markings on a severe test object such as the 
P. angulatum, until it is brought to the exact point of adjust- 
ment: they then become very distinct, almost instantaneously. 
I mention this because many suppose that in a power as low 
as this, an adjustment is not at all requisite. 

The majority of observers with the microscope, generally 
content themselves, before screwing on the object-glass, with 
placing the vernier at the mark “ covered,” or in such a place 
between the two extremes as they think may chance to be the 
right one. But this practice is not to be depended upon, for 
even admitting it to be possible that a correct judgment may 
be acquired as to the thickness of the glass cover and the cor- 
responding position of the adjustment, the latter oftentimes 
requires to be altered for different parts of the same object, 
for, frequently, the covers are not of uniform thickness, and 
various portions of the structure under view may be more 
or less deeply immersed in Canada balsam or fluid. The 
chief use of the marks “ covered” and “uncovered” are, to enable 
us, by turning to the right or left, to see in which direction the 
lenses are either separated or brought closer together. 

Although very easy in practice, there is some difficulty 
in giving any definite rules for effecting the adjustment of 
object-glasses with certainty and despatch ; but when the indi- 
cation of being out of adjustment can be clearly seen, one 
hour’s practice will be more instructive than pages of descrip- 
tion. For an uncovered object no directions are required ; 


* Since writing the above, I have been informed by Mr. De La Rue, 
and subsequently by Mr. Ross, that a similar method of measuring aper- 
tures to that here described has been used by Professor Amici for some 
years past, but I am not aware whether it has ever been published. 


138 MEMORANDA. 


all that is necessary is to set the glass to this mark, which our 
first opticians are always very particular in placing correctly. 

The following may serve as a guide for adjusting the 
object-glass for a general object that is covered. Select any 
dark speck or opaque portion of the object, and bring the out- 
line into perfect focus, then lay the finger on the milled head 
of the fine motion, and move it briskly backwards and for- 
wards in both directions from the first position. Observe the 
expansion of the dark outline of the object both when within 
and when without the focus. If the greater expansion or coma 
is when the object is without the focus, or furthest from the 
objective, the lenses must be placed further asunder, or 
towards the mark “uncovered.” If the greater coma is when 
the object is within the focus, or nearest to the objective, the 
lenses must be brought closer together or towards the mark 
“covered.” When the object-glass is in proper adjustment, the 
expansion of the outline is exactly the same both within and 
without the focus. 

On the Podura and other marked tests, we may learn to ad- 
just from a different indication. If the dots have a tendency 
to run into lines when the scale is placed without the focus, 
the glasses must be brought closer together. On the con- 
trary, if the lines appear when the object is within the focal 
point, the lenses must be further separated. 

I may state generally, that if there is a difference in the 
expansion of ‘the coma surrounding an object when quickly 
brought equally within and without the focus, the glass is not 
in adjustment. This is more remarkable under opaque illu- 
mination, but most particularly with my parabolic condenser, 
which requires the object-glass to be very accurately adjusted ; 
for if not so, the whole field of view sometimes seems filled 
with a kind of haze, and the outline of the object surrounded 
with a thick chromatic border, both of which immediately 
disappear when the adjustment is perfect, and leave the field 
intensely black. 

The foregoing remarks apply only to our first-rate object- 
glasses, for if unskilfully constructed, or badly corrected, but 
little improvement can be derived from the adjustment. 

I have for a long time objected to the mechanical method, 
by which all our opticians apply their adjustment, as there is 
oftentimes excessive friction, and that to such an extent as to 
endanger the centering of the object-glass, or to risk the dis- 
placing of the object in the endeavour to make use of it; and 
the range between ‘‘ covered” and “ uncovered” is performed 
in from one to two revolutions of the external collar. For this 
reason the motion is too slow, and the contrast between good 


MEMORANDA. 139 


and bad not sufficiently immediate to insure an accurate and 
quick adjustment. I think that the practical inconveniences 
of working this adjustment prevent its being more generally 
used by observers. As a remedy for these evils, I have al- 
ways constructed my own object-glasses with an adjustment 
of the following description: instead of moving the outer lens 
to or from the others, as hitherto, | make the former a fixture, 
and move the two inner combinations, which slide easily in the 
interior of an accurately-bored external tube, similar to a pencil 
within a pencil-case. The motion of the inner tube and its 
lenses is effected by means of a pin fixed thereto, and first 
passing through a longitudinal slit in the outer fixed tube, 
and then in an inclined slit cut in an are of 120° in the 
circumference of an exterior revolving milled collar ; the whole 
range of adjustment being thus performed in one-third part of 
a revolution. I consider that this plan has these advantages : 
the front lens (which magnifies more than the others together), 
being fixed to the outer tube, retains the same distance from the 
object, which is, consequently, not entirely lost sight of during 
the adjustment, as in the other cases where this lens is move- 
able. The motion is performed with scarcely any friction, 
and the step from good to bad or better definition, is so imme- 
diately palpable that the right point of adjustment can be hit 
upon very readily. I can generally adjust my own glasses in 
a few seconds, whereas 1 sometimes most uncomfortably 
spend several minutes in wrenching round the adjusting 
collars of our professional makers, to obtain the same result. 


—F,. H. Wenuao. 


Note to Mr. Huxley’s paper on ‘the Corpuscula Tactus ”’ 
in the preceding Number. My communication was in type 
before the publication of the last part of Siebold and Kol- 
liker’s ‘ Zeitschrift fiir Wissenschaftliche Zoologie’ (Band. V. 
H. 1), which contains two important memoirs on the Pacinian 
bodies, the one by Dr. Franz Leydig (who deserves to be 
better known in this country as one of the ablest histologists 
of Germany), ‘ Ueber die Vater-Pacinischen K6rperchen der 
Taube; the other, by Professor Kolliker, ‘ Einige Bemer- 
kungen iiber die Pacinischen Kérperchen,” Leydig points 
out several new localities in which he has met with Pacinian 
bodies in birds, particularly the interosseous spaces of the 
fore-arm and leg. His description of the structure of these 
bodies agrees very closely with that which I have given, but 
he lays a greater stress upon the transverse striation of the 
middle substance, and describes a narrow cayity in the middle 
of the so-called “central capsule,’ which he shows to be, as I 


140 MEMORANDA. 


have stated, otherwise solid, and which he regards as the ex- 
panded termination of the nerve itself. He further points out 
that his observations on the termination of the nerves in the 
invertebrata are in accordance with Wagner's doctrines, and 
takes occasion to explain at greater length his views respecting 
the analogy of the Pacinian bodies with the follicular organs 
and mucous canals of fishes. 

Professor Kolliker admits that what he and Henle had pre- 
viously named the “central cavity” of the Pacinian body in 
mammalia is solid, but still maintains the existence of a fluid 
between the outer layers, at least in the cat. He further 
points out that, in the mammalia at any rate, the central mass 
is not the expanded nerve fibril. He considers that the Paci- 
nian body of birds is essentially different from that of mam- 
mals; a conclusion which is, I think, strongly opposed by the 
comparison of young mammalian Pacinian bodies with those 
of birds. 

I must also express my regret that, having overlooked a 
paper by Dr. Waller, in the ‘ Philosophical Transactions’ for 
1848, I neglected to mention him as the original describer of 
the oe Se of the nerves in the papille of the frog’s 


tongue.—T. H. H., December, 1853. 


Stirrup’s Microscope.—I am particularly interested in the 
inquiry after a microscope, by a Thomas Stirrup, of the date, 
if | remember rightly, of the early part of the 17th century. 

May I beg your kind assistance, to make an editorial in- 
quiry in your next Number, whether any of your subscribers 
or readers possess the apparatus in question, and to solicit the 
name and address of the possessor ? 

About January, 1851, one was sold by auction in Stoke 
Newington, to a broker, as I have been credibly informed ; he, 
again, states, that he disposed of it to a medical gentleman, in 
Bayswater, but here all trace of it has been lost—F. G. 8. 


Is Coal a Mineralogical Species*—The question of the 
nature of coal having recently excited so much scientific in- 
terest, we give insertion to the following note.* 


It has long been a vexed question w ith mineralogists as to what should 
be regarded as a mineralogical species, there being many difficulties in draw- 
ing an exact definition ; ‘they are unanimous, however, in regarding a 
cry ystal as the true natural-history individual ; but as minerals more fre- 
quently occur in a massive state, they have extended the idea to those 
homogeneous bodies which exhibit the same chemical constitution through- 
out their mass. From the time of Wemer to the latest works on 


* See also, for further information, article “ Coal,” in English Cyclo- 
pedia. 


MEMORANDA. 141 


mineralogy, Coal, though never found otherwise than in a massive state, 
has been classed in all systems as a mineralogical species. Glocker, in his 
Synopsis, the latest attempt at a precise systematic arrangement of the 
Mineral Kingdom, divides Coal into three species—the non-bituminous or 
Anthracites, and the bituminous, including two species, the Black Coals 
and Brown Coals, or Lignites. In his arrangement of the varieties there 
is a gradual passage from turf and semi-fossilized wood to the most perfect 
forms of coal. 

Professor Quekett has examined, by the aid of the microscope, a vast 
number of sections of coal from various localities, as well as the Torbane- 
hill mineral; and in concluding his paper at the last meeting of the Micro- 
scopical Society, December 21st, he proves, that whilst the Torbanehill 
mineral is a resinous-looking body, nearly homogeneous, and devoid of 
vegetable structure, Coal, on the other hand, is almost entirely made up 
of woody fibre, and not homogeneous in aspect, the interstices between 
the fibres being filled with a resinous body similar in appearance to the 
Torbane mineral. Having examined many varieties of coal taken at ran- 
dom from Professor Quekett’s- extensive series of horizontal and vertical 
sections, I come to the conclusion, that Coal is nothing more than fossil 
wood mineralized by bituminous or resinous matter; and that it holds the 
same relation to such bodies as wood opal does to Opal, and is, in fact, 
similar in character to any organic remains mineralized by silex, carbonate 
of lime, or other substances. Viewed in this light, Coal has no claim to a 
place in any Mineral System as a species; if this be admitted, it will 
prove the necessity of submitting massive minerals to microscopical ex- 
amination, before their true character can be acknowledged, and before they 
can be admitted into any natural-history classification. 

The Torbane mineral seems, from the homogeneous nature of its struc- 
ture, to have greater claims to a position in a Mineral System ; and, so far 
as our present knowledge as to its other characters extends, is probably a 
mineral species sui generis. 

As it is well known that some minerals contain a vast amount of 
extraneous matter in mechanical combination, for example, the so-called 
Fontainebleau Sandstone, which consists of rhombohedral crystals of 
Caicite greatly impregnated with sand, may not the Torbane mineral be a 
true mineral species, whilst ordinary coal is the same, mechanically mixed 
with woody matter? Under the microscope, the eye cannot detect any 
difference between the matter of which the Torbane mineral is composed, 
and that which occurs between the interstices and pores of the woody 
fibres of coal. I incline, however, to the former opinion, that coal is 
nothing but a fossil wood ; therefore, not a mineral species.—S. HIGHLEY. 


Rainey’s Light Moderater.—Several persons haying ap- 
plied to me desiring to know where they can obtain the 
apparatus described in the last Number of the ‘ Quarterly 
Journal of Microscopical Science,’ for moderating the inten- 
sity of artificial light, I shall be obliged if you will have the 
goodness to say in your next Number, that the apparatus in 
question, can be obtained of Mr. Ross, optician, at a mode- 
rate cost.—GerorcE Rainey. 


( 42.) 


PROCEEDINGS OF SOCIETIES. 


Microscoricat Society. October 26th, 1858. 


George Jackson, Fisq., President, in the Chair. A paper by Dr. 
Hobson, of Leeds, “* On the Development of Tubular Structure 
in Plants,’’ was read. 

Tue author stated, that the object of this paper was to afford a 

practical illustration from Nature herself, in proof of the reality of 

that which has hitherto been but a theory in histology. For this 
purpose the structure of the hairs growing on the spurred petal of 

Viola tricolor, or Heartsease, is described as seen under the 

microscope, each hair affording in itself examples of the three pro- 

cesses considered by the author as requisite for the formation of tube. 

A linear arrangement of united cells was described as forming 
the first stage. In the second, or transition stage, the passage from 
cell into tube was shown, which was considered as produced by the 
progressive change by absorption of the axis, or primary point of 
union of the cells with each other, constituting the hitherto imper- 
vious state of hair. The third stage was described as consisting of 
the tubular condition of the tube itself, gradually and continually 
increasing during the life of the plant by the absorption of cells. 
Thus in one and the same tube, and at the same moment, a beautiful 
example of Nature’s simple mode of formation of tubular structure 
may be exhibited in this instance, consisting of a perfect cone. 

A paper by R. S. Boswell, Esq., on Actinophrys Sol, was read 
(Transactions, vol. ii., p. 25). 

A paper by Tuffin West, Esq., on the disease affecting the vine 
and other plants, was read. 

The following gentlemen were elected Fellows of the Society :-— 
Dr. Alphonse Normandy ; E. E. Lloyd, Esq.; F. George, Esq. 

November 23.--George Busk, Esq., in the Chair. A paper was 
read by the Chairman, On the Avicularian and Vibracular Organs 
of the Polyzoa (see Transactions, vol. ii., p. 26). 

A paper was read by Professor Quekett, On the Microscopical 
Structure of the Torbanehill Mineral, illustrated with numerous 
specimens and diagrams, 

T. D. Dyster, Esq.; Dr. E. Smith; J. B. Bevington, Esq. ; 
Conrad Loddiges, Esq.; J.A. Beaumont, Esq., were elected Fellows. 

December 21.-—George Jackson, Esq., in the Chair. The con- 
clusion of Professor Quekett’s paper was read (Transactions, vol. 
ii., p. 84). Dr. Bristowe and W. Travis, Esq., were elected 
Fellows. 


PHYSIOLOGICAL SECTION OF THE LONDoN Mepicau Socrery. 


In the absence of any Society in the metropolis, for the discussion 
of purely physiological subjects, the London Medical Society have 
determined to set aside one evening in the month, for the discussion 
of physiological subjects. Three meetings have been held this 


a 


PROCEEDINGS OF SOCIETIES. 143 


Session, and papers by Mr. Edwin Lee, Dr. E. Crisp, and Dr. 
Snow, have been read. These papers have been on subjects not 
necessarily involving the use of the microscope, and, therefore, not 
demanding further notice from us. We make no doubt, however, 
that this section of the London Medical Society will be made sub- 
servient to the increase of our knowledge of the functions and struc- 
ture of organic beings, by the aid of microscopical research, and we 
hope to be often called upon to report its proceedings. 


Royau Society oF EDINBURGH. 


Tuesday, December.—Sir Thomas Brisbane in the Chair. Pro- 
fessor Traill read a paper on the Torbanehill ‘ Mineral.’ He 
gave a detailed account of the local situation and geological position 
ofthe mineral in question; but these did not seem to supply any 
evidence as to the true nature of the substance. There could be 
no doubt but that it occurred in a coal formation, although he con- 
sidered this as no argument in favour of its being coal, as many 
other minerals are found under exactly similar conditions. He then 
gave a description of the substance, dwelling particularly upon 
those points which seemed to distinguish it from household coal and 
cannel coals: in its colour it was stated to differ, as well as in its 
scratch, changing colour and not being lustrous. Its thin edge, 
when held betwixt the eye and a candle-flame, was shown to trans- 
mit light. It also possessed very considerable elasticity, causing 
the hammer to rebound, and differed in its fracture from ordinary 
coals. Specimens were handed round the room to illustrate the 
various statements made by the learned Professor, who also threw 
a block of the substance into the fire, to show that it did not burn 
like ordinary coal, but produced a bright flame, never going into a 
red heat, such as would render it suitable for the cooking of meat 
and other culinary operations. He also lighted a piece of it at a 
candle, showing that it burned freely in this way, with a bright 
flame, and produced a large quantity of smoke, the carbonaceous 
matter being deposited in part upon the piece itself. Organic 
structure had been traced in the substance, but he did not deem this 
of much importance. His various researches led him to the con- 
clusion that it was not a coal, nor a parrot-coal, nor asphaltum, nor 
a bituminous shale, to which it nearly approached, but a distinct 
mineral, for which he proposed what he considered to be the most 
appropriate name— Bitumenite. 

Professor Gregory stated, that he did not consider the substance 
in question similar to a bituminous shale, as the bitumen could not 
be extracted from it by any solvent with which he was acquainted. 
He did not see any chemical evidence for regarding it as differing 
from coal. 

Professor Fleming contended that the substance, which he pre- 
ferred to call the “ Boghead gas coal,” was a coal, and a candle 
coal. What is a candle coal? asked he, and why does it get that 
name? Because it burns like a candle, which this substance does. 
And what is a parrot-coal, and why does it get that name? Because 


144 PROCEEDINGS OF SOCIETIES. 


in burning it makes a noise, “ chatters like a parrot ;” and the block 
burned in the Royal Society’s grate demonstrated that the so-called 
mineral did the same. He did not consider it a mineral at all. It 
was not formed of certain elements in certain proportions, but 
varied much in different specimens; and from these and other 
considerations, it was not a mineral but a rock; and it did not 
differ more from coal than the Craigleith sandstone did from the 
Hailes sandstone, or the Redhall did from the Granton, or the 
sandstone of Salisbury Crags did from all four. With respect to 
structure, he had seen specimens of fossil wood wherein the slightest 
trace of organic structure could not be detected under the micro- 
scope. 

Professor Bennet exhibited drawings, from the microscope, of true 
coal, and the substance in question. The latter exhibited markings, 
which he believed were regarded by the botanists engaged in the 
inquiry as cells. Now, they wanted the character of cells. The 
vegetable cell consisted of—1, a central nucleus; 2, a primordial 
utricle ; 3, a proper cell-wall ; with also included granules. Now, 
these appearances he could not find in any specimens of the 
substance submitted by him to the microscope. It was of great 
importance, he considered, to determine whether the markings 
shown in his drawing were cells or not, because the whole question 
hinged upon it, and if they were cells, then this substance showed a 
structure so profuse in cells as to be unparalleled in any other 
instance of coal. 

Dr. Greville stated, that although the markings in the drawing 
looked very like cells, still he was not prepared to say that they 
were cells in their normal condition. They might have been once 
cells, and become altered. 

Professor Balfour entered at length upon the question in its 
botanical bearings. There could be no doubt but that organic 
structure, both vascular and cellular, occurred in the disputed sub- 
stance. He alluded to the opinions of Quekett and others who had 
examined it with this view, and thought that it was wrong to draw 
any argument against the substance being coal, from the fact that 
the structure seen was not of a certain kind; coal might be formed 
of coniferous wood, in other cases it might not. We know well 
that various plants differing from the Conifere—the Stigmarias and 
others—occurred in the coal formations, and it was but reasonable 
to suppose that these contributed to the coal deposits, as well as the 
Conifere. It was impossible, therefore, to set limits to the kind of 
structure to be found. As for finding the nuclei and primordial 
utricles of cells, we could not expect that. So far from the Tor- 
banehill mineral being distinguished in general appearance from 
some kinds of coal, he had placed specimens of it and of certain 
kinds of coal, side by side, before a very competent authority, who 
could not decide which was the one and which the other. On the 
whole, therefore, he was satisfied that it was vain to attempt to draw 
any distinction between the Torbanehill substance and coal.--Con- 
densed from the “ Commonwealth.” 


TRANSACTIONS OF MICROSCOPICAL SOCIETY. 


DESCRIPTION OF PLATE II. 


ta Figs. 1, 2, 3, 4, 5.—Avicularium of Notamia bursaria. 

1.—Avicularium in the closed state. 

2.—Avicularium open, exhibiting the tactile (?) brush. 

3.—Avicularium viewed in front, to show an opening below the beak. 

4,—Avicularium in the early stage of developement. 

5.—Closed avicularium, more magnified, showing the muscular structure 
and the internal organ. 


Figs. 6, 7, 8.—Avicularium of Bugula plumosa. 


6.—In the closed state. 
7.—Open, showing the tactile (?) brush. 
8.— Open, to show the diaphragm. 


Figs. 9, 10, 11.—Avicularium of Bugula avicularia. 


9.—Open, to show the tactile (?) brush (more magnified). 
10.—Two avicularia grasping each other. 
11.—One partially open (less magnified). 
12.—Avicularium of Scrupocellaria scrwposa. 
13.—A small vermicule captured by two avicularia in Scrupocellaria 
scrupost. 
14.—Avicularium of Bugula plumosa, in the early stage of developement. 


DESCRIPTION OF PLATES III, IV., & V. 


Illustrating Professor Quekett’s Papers on the Torbane-hill 
Mineral. 


PLATE III. 
Fig. 


1.—A section of the yellow variety of the Torbane-hill Mineral, as seen 
under a magnifying power of 130 diameters. 

2.—A section of the dark variety of the Torbane-hill Mineral, as seen 
under a power of 130 diameters. The yellow circular masses exhibit 
a radiated structure; they form the combustible portion of the 
mineral, whilst the dark matter is the earthy ingredient. 

3.—A section of the Torbane-hill Mineral, in which a specimen of Stig- 
maria ficoides is imbedded : every part of this plant can be readily 
distinguished from the mineral by its rich brown colour. Mag- 
nified 6 diameters. 

4.—A portion of the same specimen magnified 50 diameters, showing how 
easily the smallest portion of vegetable tissue can be distinguished 
from the substance of the mineral. 

5,—A section of the Torbane-hill Mineral, through which a thin layer of 
coal ran, which may be readily recognised by its brown colour. 
The yellow particles of the mineral in contact with the coal are of 
more or less oval figure. 

6.—The powder of Torbane-hill Mineral, showing the yellow bituminous 
particles, and fragments of vessels. 

7.—Ash of the Torbane-hill Mineral. 


PLATE IV. 


1.—Transverse section of the Brown Methil Coal. 
2.—Longitudinal section of the same. 

3.—Transverse section of the Black Methil Coal. 
4,.—Longitudinal section of the same. 

5.—Transverse section of the Lesmahagow Cannel Coal. 
6.—Longitudinal section of the same. 


PLATE. WV. 


1.—A section showing the Mineral and Coal in juxtaposition ; magni- 
fied 3 diameters. 

2.—Representations of the comparative sizes of the transverse sections of 
the brown elongated cells from various Coals, drawn by means of 
‘the camera lucida, by Dr. Adams, 70 diameters. 

3.—Chippings of Newcastle Coal, showing dotted woody tissue. 

4,—Ash of common domestic Coal, exhibiting the remains of a transverse 
section of wood. 

5.—A longitudinal section of Coal from Lochgelly, showing its identity 
with a similar section of wood, from a drawing in the possession of 
Dr. Adams. 

6.—Ash of Coal, exhibiting portions of siliceous cuticle and other frag- 
ments of vegetable tissue foreign to the coal. 

7.—Powder of Breadisholme Coal, from a drawing by Dr. Adams. 


trina Moor pe SEEIBE Of. 


as 


7H 


_ 


rit Vi 


DESCRIPTION OF PLATE IV., 


Illustrative of Dr. Gregory’s Paper on the Diatomaceous Earth of 
Mull. 


Fig. 
‘wea variety of Epithemia Argus. 
2.—A valve of Epithemia gibberula ? 
3.—Seven varieties of Hunotia bigibba, Kiitz. 
4,.— Eunotia incisa, n. sp. 
4 8.—Variety 8, with rounded apices. 
b. Front view. 
5.—A Cymbella, qu. ? a variety of C. Helvetica? or an. sp. ? 
6.—Remarkable variety of Surirella Craticula. 
7.—Tryblianella augusta. Three modifications. 
8.—Naviceula affinis 
9.—Pinnularia tennis, n. sp. 
10.—Pinnularia undulata, n. sp. 
11.—Pinnularia parva, n. sp. ? 
12.—Pinnularia, uncertain, allied to P. radiosa or P. peregrina. 
13.—Pinnularia latistriata, n. sp. 
13 8.—Var. 8, with front view. 
14,—Pinnularia exigua, n. sp. ? 
15.—Pinnularia divergens? four varieties. 
16.—Pinnularia stauroneiformis. 
17.—Stauroneis rectangularis, n. sp. 
18.—Gomphonema Brebissonii? un. sp. ? 
19.—Gomphonema (?) Hebridense, n. sp. 
20.—A variety of Hemantidium Arcus, or possibly of 7. majus. 
21.—Remarkable sporangial pustules of Odontidium Tabellaria, 


JOURNAL OF, MIGROSCOPICAL SCIENCE. 


DESCRIPTION OF PLATE III. 
Fig. 
1, 2,3, 4, 5, 6.—From the Malpighian body of the Sheep. 
7, 8.—From that of Man. 
9, 10.—From the Tonsil of Man. 


The letters have throughout the same signification. 


a. Afferent vessel. 

b. Efferent vessel. 

c. Traversing vessel. 

¢. Capillaries. 

d. Line of junction between Red Pulp and Malpighian body. 

d’. Fibrous meshwork. 

e. Red pulp. 

J. Malpighian pulp. 

g. Endoplasts. 

h. Periplast. 

HW’. Cell-wall, 

7. Epithelium of the tonsil cavity in the section fig. 9; a vascular 
papilla is seen extending nearly to its surface. 


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ORIGINAL COMMUNICATIONS 


On the Turory of the Ittumtnation of OBsects under the 
Microscope, with relation to the ApErtuRE of the Oxpsect- 
GLass, and Properties of Licur; with Practical Methods 
for special differences of Texture and Colour. By F. H. 
WENHAM. 


Havine on a former occasion written a paper published in 
the ‘Transactions of the Microscopic Society for March, 1850,’ 
entitled, ‘On the [llumination of Transparent Microscopic 
Objects on a new Principle,” I should deem it an intrusion 
for again appearing on the same ground were it not for the 
reason that I have since that time effected some improve- 
ments, and it has become evident that the theory of the sub- 
ject was too briefly explained in my first communication to 
give a general idea of my meaning in the way that I had 
wished to be understood. As I have no predilection for a 
theory that does not bear upon a practical result, in that which 
I bring forward | shall endeavour as much as possible to sup- 
port it by experimental facts. 

I have had the major part of this memoir by me for 
some time past, and intended to have sent it to the last 
Journal, but by chance Mr. Rainey made a communication 
on the same subject, and [ have waited to learn the results of 
his investigations. As I do not agree with this gentleman in 
the inferences that he has drawn from observed facts, and the 
hypothesis that he has assumed is contradictory to the theory 
that experiment ‘has led me to adopt, I find it necessary to 
make some comment on the contents of his paper. In so 
doing, I wish it to be understood that I do not question 
the accuracy of his observation in noting phenomena; but as 
it is oftentimes the fate of deductions of this character to be 
overturned by a few practical facts, I trust that he will take 
my remarks in good part, as they are made without the 
slightest feeling of personality, and for the mere sake of 
arriving at the truth. 

Mr. Rainey first states, that when the P. angulatum is 
seen with a 1-8th of 150°, and illuminated with either the 
plain or concave mir:or, or an achromatic condenser of small 
aperture (no matter how intense the light may be), “ but 
little more than the mere outline of the object will be visi- 
ble.” This is true, and arises from the circumstance, that the 
angle of the illuminating-pencil is not sufficient to develop 

VOL. I. M 


146 WENHAM, ON THE THEORY OF THE 


the full aperture of the object-glass, for I shall show that the 
latter is dependent on the angular pencil of the illuminator. 

The author next proceeds to give a reason why the mark- 
ings which cannot otherwise be seen on test objects are ren- 
dered visible by very oblique light: he attributes this to the 
structure being composed of parts of different density and 
refractive power, which cannot be distinguished from each 
other by central or direct light; but when this is thrown on 
obliquely at a certain angle, “total reflection” will take place 
from the denser portions of the objects (meaning the mark- 
ings), while the lighter or least refractive parts will transmit 
the rays, consequently the one will appear dark and the other 
light. I may state with reference to this supposition, that 
light when incident at any degree of obliquity on diaphanous 
refracting bodies with parallel sides, cannot be made to suffer 
total reflection, either externally or internally, and admitting 
that an accidental or prismatic formation of the object did 
allow of total internal reflection, and even supposing that the 
difference of angle for producing this effect could be as great 
as between water and glass, or as 48° 36" to 41° 49", on 
increasing the obliquity of the rays only seven or less degrees, 
the markings would again become invisible, for all the light 
would then be reflected. I have never found this to occur, 
nor can I conceive how the generality of difficult tests can 
possess such a mirror-like consistency as to bring this law 
into uniform action; and therefore, from these and other 
causes, I cannot admit that this theory is at all tenable: my 
own demonstration will rest on more simple grounds, 

Attempts have sometimes been made to draw the undulatory 
theory of light into the subject of microscopic illumination, 
but without any substantial reason, as it has in reality very 
little or nothing to do with it. One of the few instances in 
which its effects are palpably seen is in the case of two lines 
being blended into one, when the object-glass has not suffi- 
cient separating power; but to avoid this it is only necessary 
to proportion the aperture of the objective to the difficulty of 
the test. I expect soon to be in a position to exemplify this 
practically. I conclude these short remarks on this head 
by stating, that I make a distinction between this and the 
interference or inflection of light, for the latter sometimes 
affects the definition of objects, under direct illumination, very 
materially, and one of the methods that I have to describe 
affords an effectual remedy. 

Mr. Rainey has given a lengthened series of observations 
on the appearance of a globule of mercury, when illuminated 
either with my paraboloid or Gillett’s condenser. I do not con- 


ILLUMINATION OF OBJECTS UNDER THE MICROSCOPE. 147 


sider that a globule, as being strictly opaque, is at all suited 
for testing an illumination intended for transparent objects, 
for however well it may show whether there is any light 
reflected, either from the brasswork, front of the object-lens, or 
thin glass cover, I cannot call to mind any ordinary object in 
which this takes place to such an extent as to create a false 
appearance. In reference to this Mr. Rainey says, “ The 
glass cover having in this instance served the purpose of a 
Lieberkiithn, has made the object appear in a false light ; and 
as nearly all microscopic examinations are made on covered 
objects, the paraboloid is in this respect defective, and the 
error must always be allowed for.” My own experiments 
have led me to a conclusion in direct opposition to this; and 
what is here pointed out as a defect is the very thing that is 
required for improving the definition ; for, as I shall presently 
explain, many transparent objects require their upper surface 
to be illuminated at the same time that the light is trans- 
mitted through them. I have for a long time used a special 
appliance to the parabolic condenser for effecting this desi- 
deratum. 

Mr. Rainey also brings forward the appearance of a globule 
of mercury when illuminated with the parabola as an example 
to show the fallacy of the ‘radiated light theory ;” but I do 
not see that it at all affects the question, simply because it is 
one of those few substances that is incapable of radiating 
light, and therefore, under such circumstances, can only be seen 
by the direct reflection of incident rays from the luminous 
source ; or, to make myself better understood, I will observe 
that the surfaces of mercury, highly-polished speculum metal, 
silver, or steel, are colourless and invisible, and from the fact 
of nearly all the light being reflected and none absorbed, are 
capable of receiving what is technically known as “a black 
polish,” which term is very descriptive. We may also give 
an exquisite degree of polish to a speculum of gold or brass, 
but in these part of the incident light will be absorbed and 
radiated in every direction, for on viewing the reflecting sur- 
face from any position we may see the metal by its colour; 
and, as a rule, any speculum that shows a symptom of this is 
not at all suited to its intended purpose, for the surface 
should be so invisible as to give the appearance of looking 
into space. I should mention here, that refracting transparent 
bodies, such as oil-globules, air-bubbles, &c., if colourless, are 
incapable of radiating light, and therefore must be seen by the 
refraction or internal reflection of the rays from the source of 
illumination, and therefore cannot be brought forward as evi- 
dence against this theory. 


mM 2 


148 WENHAM, ON THE THEORY OF THE 


I have thought it necessary to comment at some length 
upon Mr. Rainey’ S paper, as it is by far the most elaborate 
that has appeared on microscopic illumination, and I am de- 
sirous of divesting the subject of all unnecessary complexity ; 
for I will suppose the microscope itself, when in perfect ad- 
justment for spherical and chromatic aes as an instru- 
ment that in its action upon objects differs so little in principle, 
from the effect of viewing with the naked eye, that all the 
combination of lenses may be considered for the time as 
forming part and parcel of that organ. 

If in adopting this simple view of the case we do not in- 
fringe upon Nature’s laws, why should not the illumination 
of the object itself be directed by the same rule ; and reviewing 
the endless variety of forms and differences of structure, that 
we require to investigate by the naked eye, and by considering 
the position in which habit directs us to hold or place these 
for the purpose of causing the light to impinge upon them in 
the most proper direction for ascertaining their configuration 
and colour, to endeavour, as far as practicable, to apply a 
similar natural mode of throwing the light upon the micro- 
scopic object, in all instances where it is of a like contexture. 

There are chiefly two circumstances to be considered which 
prevent this principle from being directly applied in all cases 
to the illumination of objects under the microscope. The 

Fig. 1. first is that the effec- 
tive aperture of the 
object-glass in a 
great measure de- 
pends upon the angle, 
size, and form of the 
illuminating-pencil ; 
and, secondly, cer- 
tain appearances per- 
taining to the pro- 
perties of light are 
developed or ren- 
dered visible by the 
magnifying power of 
the instrument itself. 
The annexeddiagram 
will serve to explain 
the first of these con- 
ditions: a, fig. 1, is 
the object-glass ; bb, 
the extreme rays of 
he aperture ; c, the mirror; dd, rays reflected therefrom. 


ILLUMINATION OF OBJECTS UNDER THE MICROSCOPE. 149 


Suppose a test object, such as the P. angulatum, to be placed 
in the focus of the object-glass, and illuminated as thus de- 
scribed, but little else than a mere outline will be seen, and the 
vision will be rendered rather worse than better by increasing 
the intensity of the light. The non-appearance of markings 
in this instance arises from the fact that the cone of light from 
the mirror has an angle only sufficient to cause a portion of 
the aperture of the object-glass to operate effectively, or the 
object is seen with the central portion only; for on viewing an 
object by intercepted light, with the intention of obtaining the 
maximum effect of aperture, all rays converging from every 
angle of the objective, and bearing upon the object, should be 
directly opposed by rays emanating from the luminous 
source ; or, in other words, that the angular aperture of both 
the object-glass and achromatic condenser should be the same. 

The next consideration is, when the object is illuminated 
under the conditions exemplified by fig. 1, what becomes of 
the excess of aperture, or such rays from the objective as are 
not opposed by the luminous source, or, so to term it, 
‘looking into darkness,” as those from lb to d'd’? There 
can be no doubt that this portion of the aperture gives a com- 
paratively feeble image, arising from the radiations from the 
object ; but this does not assist the definition under these cir- 
cumstances, and cannot blend with the visible image because 
the central direct light is so intense in comparison as com- 
pletely to drown the faint image formed by the exterior por- 
tion of the aperture of the object-glass. 

It now remains to be shown how this radiated image may 
by itself be rendered visible. Unscrew the object-glass 
without disturbing the other arrangements, and paint an 
opaque patch of Indian ink in the centre of the front lens, 
with a camel’s-hair brush, of a diameter corresponding to the 
space d'd’. Replace the objective, and it will be found that 
the patch has obscured nearly all the rays emanating directly 
from the mirror, and the object will then be seen entirely by 
the exterior portion of the aperture, and rendered visible by its 
own radiated light.* The markings now become developed 
by the apparently paradoxical fact of destroying an operative 
portion of the object-glass; but on considering fig. 1 it will 
show that instead of seeing the object with a less area of the 
objective, we are seeing it with a greater; for in the first 
example the central portion only came into operation, and in 


* I have adopted the term “ radiated light” in microscopic illumination, 
merely because it is descriptive and convenient, and as a distinction from 
light that is simply reflected from polished surfaces, though in other 
respects not perhaps philosophically correct. 


150 WENHAM, ON THE THEORY OF THE 


the second the circumferential. I have found Smith and 
Beck’s 4-10th of 90’ a very convenient glass for trying this 
experiment; and by carefully centering the patch, I have ob- 
tained good definition of the object with a perfectly-black field ; 
so completely can the stop be made to cut off the direct rays 
from the source of light 

It is decidedly preferable to place the patch on the pos- 
terior lens of the combination, as its larger size renders the 
manipulation more’ easy. In my experiment it was about 
1-20th of an inch in diameter. ‘Those who are apprehensive 
of causing damage to an object-glass by trying this, may some- 
times obtain an approximate effect by holding the point of a 
needle just over the object when in the centre of the field of 
view. It is due to Mr. Lister to mention, that in his paper 
on the “ Achromatic Object-glass,” published in the 120th 
volume of the ‘ Transactions of the Royal Society,’ he observes 
that “some objects are even better seen when the central rays 
are obscured.” I have not brought forward this fact because 
1 think it is at all probable that any improvement can ever 
be obtained, either in the definition or illumination of objects, 
by stopping out the central pencil of the object-glass, but 
because the experiment affords a happy illustration of the 
relation that the angle of the illuminating-pencil bears to the 
aperture of the object-glass. In fig. 1, I have shown the con- 
cave mirror in use, and therefore the light is, to some extent, 
convergent ; “but with the plain mirror, all the foregoing effects 
are quite as, or even more, palpable. 

In the illumination of objects by polarized light, when 
under view with high powers, for the purpose of obtaining 
the maximum effect, it is also requisite that the angle of aper- 
ture of the polarizer should be the same as the object-glass, 
each ray of which should be directly opposed by a ray of 
polarized light. As this circumstance has received but little 
attention, [ will offer a few remarks on the polarizing con- 
denser. This instrument is merely an ordinary achromatic 
condenser of large aperture, close under the bottom lens of 
which is placed a plate of tourmaline, used in combination 
with a superposed selenite or not, as required. The effect of 
this arrangement is in some cases very remarkable, bringing 
out strongly colours which are almost invisible by the usual 
mode: it is most useful for small bodies, such as the bitumen 
granules of the Torbane-hill mineral, &c. 

To obtain a greater quantity of light, I would recommend 
that the iuminating lenses should be of the same diameter as 
a half-inch object-glass of large aperture, for it is oftentimes 
a fault with the achromatic coficeneer that these are too small ; 


ILLUMINATION OF OBJECTS UNDER THE MICROSCOPE. 15] 


for it should be remembered that in all condensing arrange- 
ments the intensity of the light as much depends upon the 
diameter of the lenses as their angle of aperture. The reason 
why this instrument has not received more universal adoption 
has been the scarcity and expense of good and large tourma- 
lines; but now that Dr. Herapath has made the valuable 
discovery of producing them artificially, and the liberal manner 
in which he has published all the details of their manufacture 
to the world, will no doubt be the means of causing the 
polarizing condenser to come more into use, 

Before quitting the subject of direct light, I will make one 
or two remarks on the known methods of obtaining it. The 
plain and concave mirror, or right-angle prism, are the most 
generally useful for glasses of low power and small aperture: 
in principle these are so well known as to need no comment ; 
but for objectives of large aperture there is no instrument 
better adapted to its intended purpose than Gillett’s con- 
denser, for its series of stops allows us to enlarge or diminish 
the angle of the illuminating pencil, and therefore possesses 
the valuable property of causing the effective aperture of the 
object-glass to be reduced or increased, on the principle just 
explained, to suit the description of object under view, thus 
in a great measure correcting the false appearance caused by 
large apertures in objects of bulk.* 

I will now proceed to show the effect of oblique illumina- 
tion, and the dependence of the aperture of the object-glass 
on its direction. 

If the concave mirror be moved slowly sideways from the 
axial line of the microscope as shown in fig. 1, the intensity 
of the light will gradually diminish, and after a certain time, 
the striz or markings of the object (which is supposed to be 
the P. angulatum as before) will become more and more 
visible, and increase in distinctness, till the least obliquity 
of the illuminating pencil is in a direction a few degrees 
within the extreme angle of the aperture of the object-glass ; 
ee, fig. 1 represents the mirror in this position. The external 
rays, f, are shown to enter the objective, but the remaining 
portion of the reflected cone of light to f’ passes the exterior 
of the aperture without entering. 

Every microscopist is familiar with the effect of this expe- 
riment, but not with the cause, which may be explained on 
precisely the same principle that I have exemplified by the 
objective with the central patch. The axial position of the 
mirror shown in fig. 1, as I before mentioned, does not permit 

* For explanation of which see my Paper on “ Binocular Vision,” ‘ Quart, 
Journal of Microscopical Science,’ Oct. 1853. No. 5. 


152 WENHAM, ON THE THEORY OF THE 


the markings to be seen, because the intense light, and small 
angle of illumination, allows only the centre or a small 
portion of the aperture of the object-glass to act effectively. 
But on moving the mirror aside from the axis of the micro- 
scope, a part of the light illuminating the object at length 
begins to pass the extreme of the angle of aperture of the 
objective, and as the field becomes more obscure, the mark- 
ings on the object itself increase in distinctness, simply 
because a corresponding portion of the aperture of the object- 
glass is called into action in collecting the radiations. 

In the position of the mirror, e e, fig. 1, nearly the whole 
of the object-glass will be effective, as it will collect the 
radiations from the object from every angle within its aperture, 
and no portion of the latter will be annulled by the predomi- 
nance of the intense rays from the luminous source. Practically 
it is found that there is a precise but different angle of illu- 
mination required for every aperture of the object-glass, in 
order to give the maximum of distinctness; or that will even 
at all develop the markings on difficult tests. For if we 
continue to increase the angle of the mirror, e, e, the object 
first acquires a pearly appearance, and is afterwards seen in a 
dark field known as “ Reade’s back-ground illumination,” 
and is then rendered visible with a full aperture, entirely by 
its own radiations; but the markings have again become in- 
distinct or disappear altogether, showing that it is needful 
to allow a small portion of the light from the source of illu- 
mination to pass into the object-glass, and through the object, 
that the striae may either be rendered more visible by the 
rays that they intercept, or that the field shall be partly 
luminous. 

There is one peculiar phenomenon attendant upon oblique 
illumination at certain angles in one direction, and may be 
described as a double image, or kind of overlying shadow, 
having in some instances markings equally distinct with those 
on the object itself. This appearance has been termed the 
“ diffracting spectrum” among men of science. ‘Taking the 
name to be descriptive, | sought for an explanation in the 
known laws of the diffraction of light, but these did not 
account for it, for on this theory I attempted to find the clue 
in vain. I have since traced the cause entirely to the mutual 
dependence of the angles of illumination and aperture, de- 
tailed in this paper. One image is caused by the radiations 
from the object entering one portion of the object-glass, and 
a different one by the object being directly seen by intercepted 
light with the other extreme of the aperture, thus giving the 
appearance of a double image. ° In proof of this, hold a card 


ILLUMINATION OF OBJECTS UNDER THE MICROSCOPE. 153 


over that side of the front lens of the objective which receives 
the light from the luminous source, and one image will dis- 
appear: on reversing the card, so as to cut off the other 
extreme, the first image will appear again, and the second 
vanish. 

The “ diffracting spectrum” may also be produced at 
pleasure, in an object illuminated by direct light, and seen 
with a large aperture, by holding a needle or horse-hair 
before the front lens, so as to split the pencil into two parts. 
The above misnomer led me somewhat astray, as is oftentimes 
the case in matters of science, where terms are applied to 
phenomena that are not understood, but I have no doubt 
that the explanation that I have here given is the true one; 
if necessary, I could adduce further proof, but any one 
desirous of testing it will find other corroborative facts, 

It is well known that besides the detriment to the definition 
of the object, caused by the double image just described, 
there are other errors created by oblique light from one side 
only, such as blending a series of dots into lines, &c. I sug- 
gested about four years ago, that these defects should be 
neutralized or “ counteracted by a pencil of light of similar 
form and intensity thrown on the object at the same angle 
from an opposite direction.” To effect this, I proposed that 
two of Nachet’s prisms should be placed oppositely, under- 
neath the stage of the microscope, with a dark well between 
them: this led me to the discovery of the principle of throw- 
ing the light on the object circularly, and preventing “ the 
central direct rays” from the illuminator from entering the 
object-glass, by means of a dark well or stop, as illustrated by 
my parabolic condenser. My paper on this subject was pub- 
lished in vol. iii. of the ‘Transactions of the Microscopical 
Society, March 1850,’ but I regret that an insufficient detail 
of the principles involved, and a want of care in the expres- 
sion, should have given rise to some insidious misconstruction ; 
but as a proof of the utility and correctness of my theory, I 
have only to mention the many applications of it that have 
since that time come into general use, in the way of adapting 
central stops to the achromatic condenser, single and com- 
pound lenses, &ce. 

There are some appearances connected with oblique illu- 
mination, on closely-lined glass micrometers and tests, which 
would occupy too much space to enter upon here; but on a 
future occasion, I will make this the subject of a separate 
communication, as [ shall soon have in hand an apparatus that 
will illustrate the changes of prismatic colours, with different 
angles of illumination and vision. 


154 WENHAM, ON THE THEORY OF THE 


I have now to treat of such methods of illumination as do 
not interfere with the aperture of the object-glass, or affect the 
properties of light, and are, therefore, so simple in their 
action as to allow us to consider the microscope when in 
use as forming part of the eye, and to judge of the quality 
and direction of the light required by a consideration of the 
simple laws of nature, comprised in the illumination of all 
surrounding bodies of comparative form and texture. 

The first relates to ordinary opaque illumination, by merely 
condensing the light on the object, either by means of a 
Lieberkiihn’s lens, or side reflector: this is too simple to need 
any comment, and is mostly used for objects that are nearly 
destitute of transparency, and therefore cannot be seen in any 
other way. 

The next is “ Reade’s background illumination,” in which 
the light is thrown under the object in such a direction as to 
avoid or pass by the aperture of the object-glass, and give a 
black field. The structure under view, if large, must possess 
a sufficient degree of transparency to allow the light to enter 
into its substance, and be diffused or radiated therefrom in all 
directions. This method is but little used, on account of the 
light being feeble and partial, and because shadows are thrown 
in one direction. 

When the stop of my parabolic condenser is raised, so as 
to obtain a black field, it is nothing more in principle than 
the ‘ background illumination” carried round the circle, and 
the object, though transparent, is rendered visible by the 
operation of the same laws which enable us to see an opaque 
substance. I will therefore make use of the same illustration 
as on a former occasion. Lay a black wafer upon a sheet of 
white paper, and hold the wing of a fly a small distance above 
it; this evidently appears to be transparent, though no light 
passes directly through it into the eye. ‘The object also shows 
an iridescent play of colours, from the decomposition of the 
light thrown upon its surface by the surrounding hemisphere. 
The Jast is a condition that I have found wanting in my 
paraboloid, for if we illuminate with it such objects as 
feathers, foot of a diamond beetle, of scales, &c. by artificial 
light, instead of brilliant colours, the surface will have a dull 
leaden aspect. 

I have endeavoured to imitate the effect of the vault of the 
universe, by the method shown by fig. 2: @ a, is the parabolic 
condenser, b b, the glass slide upon which the object is 
mounted ; this also serves to support the hemispherical re- 
jlector, cc: the top of this is cut away so as to leave an 
opening of sufficient size to admit the nozzles of any one of 


ILLUMINATION OF OBJECTS UNDER THE MICROSCOPE. 155 


the object-glasses. It will be seen that when the centre of the 
hemisphere and focus of the Fig, 2. 

parabola are coincident, the 
light passing the object being 
incident at right angles on the 
spherical surface, will be re- 
flected directly back again, 
and so illuminate the upper 
surface of the latter. The 
reflector that I have used is 
made of silver; but I propose 
to construct them of a zone 
cut from a blown-glass bulb, 
of about one inch in diameter, 
silvered by Drayton’s process, . 
and cemented into a brass cup with electrical cement. I be- 
lieve that Lieberkiihn’s might be made in the same way, as they 
would then have the advantage of not being liable to tarnish, 
and would bear to be wiped. I have found the upper 
reflector just described to answer its peculiar purpose ; and 
before quitting this head, | must express my desire of divesting 
the principle of all complexity, by again stating, that the 
parabolic condenser is merely a modification of opaque illu- 
mination applied to transparent objects, and that it gives a 
degree of intensity to the light not obtainable by any other 
method. 

When strictly opaque bodies of minute size, such as shells, 
grains of sand, calcareous particles, &c. are illuminated, even 
without the upper reflector, they are seen after the usual 
manner of all opaque objects. On the other hand, when such 
substances as show colour only when exhibited as transpa- 
rencies, such as bits of clear and well-polished stained glass, 
are placed over the paraboloid, they will be quite invisible ; 
but if the surface be greasy, or covered with dust, the colour 
of the glass may be known by similar coloured radiations 
from these particles. 

When we take a small object into the hand for examination, 
without any direct appeal to the reasoning faculties, a sort of 
instinct usually guides us to hold it in one of two positions, 
either against a dark body, or over a sheet of white paper, as 
may be most suitable for the development of the structure or 
colour of the substance. The first of these conditions is 
already imitated, in its application to the microscope, by the 
parabolic condenser, by means of which the light is thrown 
on the object “from every azimuth,” as Mr, Shadbolt has 
aptly termed it. 


156 WENHAM, ON THE THEORY OF THE 


The second position, which gives such delicate vision of 
some substances, does not appear to have been truly consi- 
dered in its relative application to the illumination of micro- 
scopic objects. It is true that in the place of the mirror, a 
plaster-of- Paris, or enamel plate, has been applied, for obtain- 
ing the effect of a white cloud, and used either with or without 
interposed condensing lenses; but this does not quite answer 
to the conditions above referred to, for the rays diffused from 
a sheet of paper will pass, from every angle and direction, 
through the under surface of the object, and if this is held 
close, not only is the light more intense, but some portion of 
it must enter at very oblique incidences. The first step 
towards obtaining a corresponding effect in the microscope is 
to lay the slide on a sheet of clean white paper, and to throw 
a strong light upon it through and around the object, by 
means of the bull’s-eye lens. In some instances, this gives a 
very good result, but if the object is large, it casts a shadow 
upon the paper, which mars its whiteness; it is therefore 
better to employ a small enamel or plaster-of-Paris disc in 
the place of the common dark well: this can be lowered suffi- 
ciently to cause the shadow to recede from the field of view. 
A thick black line should be drawn across the white disc, 
which may in certain cases be brought directly under some 
objects, by turning the supporting arm sideways; this will 
sometimes be found materially to assist the development of 
their structure: some tests acquire a pearly appearance from 
the oblique radiations from the enamel surface. 

The method just explained gives some promise, but can 
only be used well with the lowest powers, and even with 
these, it is scarcely possible to condense the light on the disc 
sufficiently strongly. The close proximity of the highest powers 
to the object prevents the disc from being illuminated in this 
way ; it is therefore necessary to use a diffusing film of partial 
transparency, in order that it may be lighted from underneath. 
I have had much difficulty in finding a material that will 
diffuse light well, and yet be microscopically structureless ; 
for example, finely-ground glass diffuses transmitted light, but 
the grey appearance is caused by the contrary prismatic effects 
of an aggregation of bright fractures, which however minute 
they may be, are singly still larger than many of the objects 
to be viewed, so that instead of the illumination being a 
diffused, it may chance to be an oblique chromatic one. 
I have tried various kinds of enamel, but the best material that 
I have yet found is unbleached or yellow bees’-wax ; this con- 
sists of numberless minute spherules which disperse the light 
very effectually. 


ILLUMINATION OF OBJECTS UNDER THE MICROSCOPE. 157 


The method of applying this is as follows: select two 
circles of thin glass about one-quarter of an inch in diameter, 
and place a shaving of the wax between them, then warm the 
whole slightly, and compress the wax, till on looking through 
it the flame of a candle just begins to appear visible. The 
disc is then to be mounted in a piece of tube, of a size suffi- 
cient to cause it to slide easily over the top of the ordinary 
achromatic condenser, so that the film may be adjusted exactly 
in its focus. When the apparatus is fitted in place, throw the 
light through the full aperture of the condenser, by means of 
the concave mirror, and bring the intensely-bright spot of 
diffused light thus formed, close under the object, by the rack 
and pinion: thus, for a trifling expense, a most useful and 
simple illuminator may be procured; but there is still much 
improvement to be expected, from the discovery of a better 
diffusing material than bees’-wax, but this I have not up to 
this time succeeded in finding. 

The methods of illumination last described serve to show 
some objects which cannot be seen with the paraboloid, 
though others are equally well displayed with both. The 
effect of diffused light is to give a greater depth or perspective 
to the object, or a more just appreciation of distance between 
particles, or superimposed tissues, together with an agreeable 
softness, and an entire absence of the interference caused by the 
decomposition of direct light, which is known to act so preju- 
dicially to the definition of some objects illuminated in the 
ordinary way. ‘There is also another fact worthy of notice: it 
is observed how difficult it is to examine glass tubes, without 
our being deceived by direct reflection or refractions, but if we 
illuminate sponge-spicules (which are literally minute glass 
tubes) with diffused light when under the microscope, we get 
rid of these refractions, and they appear perfectly smooth, and 
their tubular structure is quite evident, for the diffusing film 
answers a similar purpose to the ground-glass shade or cap of 
the kaleidoscope which prevents the direct refraction of light 
from taking place, through the enclosed broken pieces of 
coloured glass. 

I will suggest, that perhaps in some cases another diffusing 
dise, perforated and placed over the object, might be of adyan- 
tage, so as to enclose it in a kind of luminous tent. 

In conclusion, I must state, that I have carried the foregoing 
subject to a greater length than I had previously intended, and 
yet omitted some curious facts relating to illumination througn 
coloured media, as possessing no great amount of practical 
utility, for monochromatic light was originally suggested for 
the purpose of remedying a defect in the objective; but as 


158 HEPWORTH, ON THE FOOT OF THE FLY. 


these are now made so as to be incapable of decomposing 
compound light, all such methods must consequently be con- 
sidered obsolete. 

In advocating the principle of copying from natural effects, 
in the application of illumination to microscopic objects, I 
believe that I have advanced nothing that is preposterous, but 
flatter myself that I have already made some successful ad- 
vances in this direction, and I am of opinion that by keeping 
this point in view ‘in effecting improvements, good will result 
from it in that department, where the microscope is most use- 
fully employed in the examination of all ordinary objects, and 
if the binocular microscope should eventually approach to 
perfection, and thus enable us to combine natural vision with 
natural illumination, it will give to objects an appearance of 
reality of which we can at present form but little conception. 

And, finally, as all the observations here detailed are the 
result of direct experiment, I advance them with confidence ; 
and if I have brought forward but little that is novel, I 
venture to hope by the explanation that I have given of the 
relation that angles of aperture and illumination bear to each 
other, that I have cleared away some part of the fog that has 
prevented this portion of the subject from being in many 
instances more clearly understood, 


On the Structure of the Foor of the Fry. By Joun Hrp- 
worTH, Esq., Surgeon. 


Havine paid some attention to the structure of insects, I have 
carefully examined the fly’s foot (Musca domestica, &c.), and 
finding much misapprehension on the subject still existing (in 
arecent popular publication), I thought a few remarks might 
not be uninteresting to some of the readers of this Journal, 
and lead to a further investigation by some one more expe- 
rienced in these matters than myself. Some months after | 
had arrived at my conclusions I met with the following remarks, 
some of which come nearer my own ideas than anything I 
have yet met with: — 

‘“¢ Another interesting peculiarity observable in the domestic 
fly arises from the structure of its feet, enabling it to walk 
with the greatest facility, not only upon upright surfaces, but 
also upon the ceilings of rooms, back downwards, without its 
position being disturbed in consequence of being contrary to 
gravity. Much diversity of opinion has taken place amongst 
naturalists upon this curious subject ; and even in the latest 
works we find the matter still fornting a “ questio vexata.” 


HEPWORTH, ON THE FOOT OF THE FLY. 159 


Dr. Derham, in his ‘ Physico-Theology,’ speaking of the 
means whereby insects maintain their position upon smooth 
surfaces, states that “divers flies and other insects, besides 
their sharp-hooked nails, have also skinny palms to their feet, 
to enable them to stick to glass and other smooth bodies by 
means of the pressure of the atmosphere, after the manner as 
I have seen boys carry heavy stones, with only a wet piece of 
leather clapped on the top of a stone.” Gilbert White, of 
Selborne, adopted Derham’s opinion, adding that, although 
the flies are easily enabled, from their lightness and alertness, 
to overcome the weight of air in warm weather, yet that in the 
decline of the year this resistance becomes too mighty for 
their diminished strength, and we see flies labouring along, 
and lugging their feet in windows as if they stuck fast to the 
glass, and it is with the utmost difficulty that they can draw 
one foot from another, and disengage their hollow caps from 
the slippery surface. 

This opinion, which has been entertained by the majority 
of entomologists of the present day, has acquired additional 
weight by the elaborate investigations of Sir Everard Home, 
undertaken at the suggestion of Sir Joseph Banks, with the 
assistance of that (then) unrivalled microscopic artist, M. Bauer, 
and published in the ‘ Philosophical Transactions’ for 1816. 
The suckers, of which several kinds of flies possess three to 
each foot, are attached beneath the base of the claws, and are 
of an oval shape and membranous texture, being convex above, 
having the sides minutely serrated, and the under concave 
surface covered with down or hairs. In order to cause the 
alleged vacuum, these suckers are extended ; but when the fly 
wished to raise its legs, they are brought together, and folded 
up as it were between the hooks. Messrs. Kirby and Spence 
have likewise adopted this opinicn, considering it as ‘* proved 
most satisfactorily.” Other authors of no mean repute have, 
however, entertained a different opinion, and have entirely re- 
jected the idea of a vacuum being produced. Thus Dr. Hooke 
describes the suckers as palms or soles, beset underneath with 
small bristles or tenters, like the cone teeth of a card for work- 
ing wool, which he conceives gives them a strong hold upon 
objects, having irregular or yielding surfaces ; and he imagined 
that there is upon glass a kind of smoky substance, penetrable 
by the points of these bristles. The same opinion is also 
given by Shaw in his ‘ Nature Displayed ;’ and more recently 
Mr. Blackwall has considered that the motions of the fly are 
to be accounted for upon mechanical principles alone ; thus, 
upon inspecting the structure of the parts of the suckers, “it 
was immediately perceived that the function ascribed to them 


160 HEPWORTH, ON THE FOOT OF THE FLY. 


by Dr. Derham and Sir E. Home is quite incompatible with 
their organisation. Minute hairs, very closely set and directed 
downwards, so completely cover the inferior surface of the 
expanded membranes, improperly denominated suckers, with 
which the terminal joint of the foot of flies is provided, that it 
cannot possibly be brought into contact with the object on 
which those insects move by any muscular force they are 
capable of exerting; the production ef a vacuum between 
each membrane aid the plane of position is, therefore, clearly 
impracticable, unless the numerous hairs on the under side of 
these organs individually perform tlie office of suckers; and 
there does not appear to be anything in their mechanism which 
in the slightest degree countenances such: an hypothesis. 
When highly magnified, their extremities, it is true, are seen 
to be somewhat enlarged ; but when they are viewed in action 
or in repose, they never assume a figure at all adapted to the 
formation of a vacuum.” Moreover, on enclosing a house-fly 
in the receiver of an air-pump, ‘it was demignkiaatad to the 
entire satisfaction of several intelligent gentlemen present that 
the fly, while it retais its vital powers unimpaired, cannot 
only traverse the upright sides, but even the interior of the 
dome of an exhausted receiver; and that the cause of its re- 
laxing its hold, and ultimately falling from the station it 
occupied, was a diminution of muscular force, attributable to 
impeded respiration.” Hence Mr. B. is induced to believe 
that insects are enabled to take hold of any roughness, or 
irregularity of surface, by means of the fine hairs composing 
the brushes, the most carefully-polished glass not being found 
free from flaws and imperfections when viewed in a favour- 
able light with a powerful lens. A still different opinion has 
been maintained by other authors upon this subject, who, 
setting aside all idea of a vacuum, have conjectured that the 
suckers, as they have been termed, contain a glutinous secre- 
tion, capable of adhering to well-cleaned glass; thus, Abbé 
de la Pluche states, that when the fly marches over any 
polished body, on which neither her claws nor her points can 
fasten, she sometimes compresses her sponge, and causes it to 
evacuate a fluid, which fixes her in such a manner as prevents 
her falling, without diminishing the facility of her progress ; 
“« but it is much more probable,” he adds, ‘that the sponges 
correspond with the fleshy balls which accompany the claws 
of dogs and cats, and that they enable the fly to proceed with 
a softer pace, and contribute to the preservation of its claws, 
whose pointed extremities would soon be impaired without 
this prevention. Notwithstanding the ridicule which has been 
thrown upon this opinion in a “eGo entomological work, it 


HEPWORTH, ON THE FOOT OF THE FLY. 161 


appears, from still more recent investigations, to be the best 
founded of any hitherto advanced. Thus, an anonymous 
writer has published an account of various experiments and 
examinations upon this subject, which appear satisfactorily to 
prove that it is not by the application of extremely small 
points to invisible irregularities on the surface of glass that 
the pulvilli or suckers are attached, but by simple adhesion 
of the enlarged ends of the hairs, assisted by a fluid that is 
probably secreted there ; and the author is, therefore, reduced 
to refer the effect to molecular attraction only. It is also 
stated that when the foot is detached, a distinct fluid trace will 
often be left by each individual hair, the spotty pattern thus 
left on the glass appearing to be of an oily character, for if 
breathed on it remains after the moisture is evaporated. The 
contrary opinion, although contained in a review of Mr. Black- 
wall’s Memoir, above noticed, was evidently written in igno- 
rance of the subsequent observations of that author contained 
in the appendix of the volume in which it appeared, and in 
which several facts are stated, which appear “quite inex- 
plicable, except on the supposition that an adhesive secretion 
is emitted by the instruments employed in climbing ;” and it 
is subsequently affirmed that careful and repeated examina- 
tions made with lenses of moderately high magnifying powers, 
in a strong light, and at a favourable angle, speedily convinced 
Mr, Blackwell that his conjecture was well founded, as he 
never failed to discover “ unequivocal evidence of its truth.” 
— fistory of Insects, London, 18385. 

In general the foot of the fly is described as being com- 
posed of two hooks and two flaps, or hollow cups, which act 
as suckers. Rymer Jones, in his ‘ General Outlines of the 
Animal Kingdom,’ 1841, says, “The house-fly is furnished 
with a pair of membranous flaps, which, under a good micro- 
scope, are seen to be covered with innumerable hairs of the 
utmost delicacy ; these flaps, or suckers as they might be 
termed, adhere,” &c. In the publication alluded to in the 
commencement, September Number, 1853, the writer says, 
** In addition to the two hooks upon the last joint of the foot, 
we of tenmeet with flaps or suckers, Kc., which,” he goes on 
to say, ‘are beset with long stiff hairs, to keep them from 
dust and injury.” The flap varies in form in different species 
from an irregular circle to that of an irregular triangle, and, 
viewing it from one side, it is somewhat thicker at its base 
(near its attachment), the under surface being, when isolated, 
convex, but perfectly flat, as a whole, when applied to a 
surface of that form. It appeared to be composed of an 
upper and under layer of areolar tissue, or something similar 

VOL. It. N 


162 HEPWORTH, ON THE FOOT OF THE FLY, 


to it, between which a bundle of tubes, along with the fasci- 
culi of a large muscle, pass; these are placed at its base, 
and (sometimes protected by a coat of mail, formed by long 
scales overwrapping each other, as a Wienevnal blind, or in 
alternate ones, as the scales on a fish, &c., but more frequently 
wanting) expand in a radiated form ; each tube, as it passes 
along with its fellows on each side, gives off a number of 
tubules alternately with them; these dip downwards from 
the under surface, and become expanded into trumpet-shaped 
extremities, the flap becoming thinner and thinner as it 
approaches its margin, which sometimes terminates in an 
irregularly serrated edge, and at others by finely-pointed 
hairs. ‘The fly has the power of attaching itself to smooth 
surfaces by these trumpet-shaped extremities, and also of 
secreting a fluid from them when vigorous, and has occa- 
sion to make extra exertions ; but in a partially dormant state 
(the best for making observations), it does not appear to be 
able to give out this secretion, although it can still attach 
itself; indeed this fluid is ae essential for that purpose: 
when it is secreted, it is deposited on the glass with great 
regularity. I have often attempted to preserve these mark- 
ings, by applying colouring matter whilst they were moist ; 
but have not yet succeeded, The tubules are often seen pro- 
truding from under the margin of the flap in a semiarch-like 
form, giving it a fringed appearance. ‘The foot of the male 
Dytiscus is a type, not only of many of the beetle tribe (not 
aquatic), but of the whole of that of flies possessed of flaps. The 
first joints of the tarsus of the anterior legs of this insect are ex- 
cessively dilated, so as to form a broad circular palette (fig. 1, 
Plate V.). On examining the inferior surface of this expanded 
portion, it is seen to be covered with a great number of suck- 
ing cups, two or three (three in the specimen, fig. 1, a, b, b) 
being larger than the rest, but they form collectively a won- 
derful instrument of adhesion. Fig. 1, ce, represents the small 
suckers ; fig. 2 and 3, the same enlarged, as they appear when 
mounted, and viewed with a power giving about 225 diame- 
ters. Fig. 4 (50 diameters) is the foot of a rather large fly, 
which shows the parts so well, that I have chosen it; it isone 
which appears to subsist on pollen, and is found on umbel- 
liferous plants. The parts are too obvious to require a de- 
scription. I would remark that the edges of the flaps have 
got turned in mounting, which shows the suckers more dis- 
tinctly. Fig. 5 (550 diameters), an enlarged view of the 
portion of Fig. 4, a. Fig. 5, 6, appearance of the under 
(through the upper) layer of the flap, showing the points 
from which the tubules are given off. Fig. 6 back, Fig. 7 


DR. ALLMAN, ON THE STARCH GRANULE. 163 


front, and Fig. 8, 9, side views, when isolated and at rest. 
Fig. 10 foot of horse or gad fly, seen from above. Fig. 11, 
the under surface of a fly’s foot, as presented to the eye when 
in action. The outlines of the sketches have been taken with 
the camera lucida. 


Linear Inch. 

The length of tubules from the under alae es 8 
of the flap, vary from - - T2059 TE0 
Distance of rows - - - - sta 10 qahss 


Expanded ends at rest (being much raed Nas 
when inaction - - x a 3000 © To000 
Thickness of shaft of tubules = Ags 80 Shas 


REMARKS on the INVOLUTION THEORY of the STARCH GRA- 
NULE, and on the probable Structure of this Bedy. By GEo. 
James ALLMAN, M.D., M.R.I.A., Professor of Botany in 
the University of Dublin.* 


Iv is now about twenty years since Fritzsche published the 
results of a series of careful and elaborate observations on the 
structure of the starch granule.j Fritzsche examined starch 
obtained from the potato and from several other plants, and 
concluded that the granule was composed of a series of layers 
of entirely similar composition, surrounding a minute central 
body or “nucleus,” whose behaviour under certain circum- 
stances rendered it probable that it differed chemically from 
the surrounding layers : he maintained that in the formation 
of the starch granule these layers are deposited one over the 
other from within outwards, and that the peculiar concentric 
striz visible in the granule indicate the surfaces of contact of 
the layers. 

In this view Fritzsche places himself in direct opposition to 
Raspail, who had just asserted that the starch granule was a 
vesicle consisting of an external thin wall, insoluble in water, 
and enclosing soluble contents, and that the striae were merely 
superficial markings. 

Since the publication of Fritzsche’s memoir, which must be 
considered as the basis of all the knowledge we at present 
possess on the structure of the starch granule, numerous 
observers have applied themselves to the investigation of this 
body, and have advanced very different and often contradictory 
views as the result of their inquiries. So great, however, are 
the difficulties by which the subject is surrounded, that, so far 


* Read at a meeting of the Royal Irish Academy, Jan. 9, 1854, and 
communicated by the Author. 
+ Poggendorff’s Annalen, 1834. 


164 DR. ALLMAN, ON THE STARCH GRANULE. 


as the structure and genesis of the granule are concerned, our 
positive knowledge can scarcely be said to have advanced a 
single step beyond the condition in which it had been left by 
the memoir of Fritzsche. 

Amid the different conflicting statements* respecting the 
structure of the starch granule, there has recently been ad- 
vanced a view which at first sight appeared to lead to most 
important results, as giving us an entirely new and unexpected 
conception of this difficult question. 

M. Martin,} of Vienna, desirous of observing the changes 
which take place in potato starch during the action of hot 
water, contrived a simple expedient by which these changes 
could be watched under the microscope through the whole 
course of their progress. From observations thus conducted 
he arrived at the conclusion that the phenomena which occur 
during the action of hot water on the starch granule consist 
essentially in an evalution or unrolling of a compressed vesi- 
cle ; that the starch granule, therefore, in its natural condition, 
is really a vesicle compressed into a disc-shaped body, and 
having its edges rolled inwards upon themselves, while the 
concentric striz indicate the coils of the sort of volute thus 
formed. 

This theory, presenting as it does an exceedingly elegant 
and attractive view of the subject, and appearing to be the 
result of careful observation, naturally excited much interest. 
In the third Number of the present ‘ Journal’ is a valuable 
paper on the starch granule by Mr. Busk: in this paper, 
accompanied by beautiful figures, the author details a series 
of interesting and accurate observations, which he believes 
tend to confirm in all essential particulars the theory of 
Martin. Instead of observing the granules under the action 
of hot water, in the way done by Martin, Mr. Busk adopts the 
more easy process of acting on the granule by strong sul- 
phuric acid, and watching the successive stages through which 
it passes during the continued action of the acid. The effect 
of the sulphuric acid is very similar to that of hot water, and 
whatever conclusions are derivable from the one method of 
experimenting seem equally to follow from the other. 

Notwithstanding, however, the accuracy which it is impos- 
sible to deny to the observations of the German and English 
naturalists, I have been led, after carefully repeating their 
experiments, to arrive at an entirely different conclusion, and 


* For an analysis of the more important views concerning the structure 
of the starch granule, I may refer the reader to Mr. Busk’s paper in the 
third number of this Journal. 

+ Philosophical Magazine, April 1852. 


DR. ALLMAN, ON THE STARCH GRANULE. 165 


it is chiefly with the hope of eliminating from the already 
too-complicated history of the starch granule, a new element 
of confusion which the theory of Martin appears to me to have 
introduced into it, that I publish my own researches on the 
subject. 

If potato starch,* exposed for three or four weeks to the 
action of a solution of iodine, formed by mixing about equal 
parts of water and the common tincture of iodine, and a few 
of the deep indigo-blue granules, be then placed on a slip 
of glass under the microscope, and wetted with a drop of 
dilute sulphuric acid (about three parts strong acid and one 
water), the granules will immediately begin to swell, but 
much more slowly and to a less extent than in the case of un- 
iodinized granules. When the swelling consequent upon the 
action of the acid has ceased, many of the granules may be 
seen with several of their lamellz beautifully dissected from one 
another, exhibiting frequently considerable intervals between 
the layers, and demonstrating, in the most complete manner, 
the composition of the granule out of a series of concentric 
shells (Pl. VI., figs. 1, 2). The condition thus produced seems 
to be due to the iodinized granule not admitting of a suffi- 
ciently-uniform expansion of all its parts at the same time, so 
that some of the layers tear themselves away from the others. 
It frequently happens that some of the external layers will 
become ruptured, and by then peeling off like the coats of 
a bulb, will render the structure still more evident (fig. 2). 

The mode of operating just described is perhaps the most 
certain in causing the detachment of the layers from one 
another, but the same phenomenon may be produced by other 
means. Payenj has figured the exfoliation of starch granules, 
which, after being exposed to a high heat without moisture, 
were then wetted with water; and Schacht§ describes a 
similar effect from the action of a solution of iodine in chlo- 
ride of zinc. If the starch be exposed to heat upon a metallic 
plate till it has acquired a light-brown colour, the strie will 
be observed in many of the granules, when examined under 
the microscope, to have become even more distinct than 
before the operation of the heat, while the spot corresponding 


* The observations contained in the present paper are to be understood, 
except when otherwise stated, as having been made upon the starch of the 
potato. I have examined, however, very many varieties of starch, and in 
no case has anything been seen to invalidate the views here taken. 

+ It seldom occurs that more than four or five distinctly separated shells 
become visible in this experiment ; each of them, however, must be sup- 
posed to be composed of a greater or smaller number of primitive lamellz. 

f Mémoires sur les Développements des Végéteaux. 

§ Die Pflanzenzelle. 


166 DR. ALLMAN, ON THE STARCH GRANULE. 


to the nucleus of Fritzsche will have become much enlarged, 
and is now plainly a cavity filled with an aeriform fluid. If 
to these granules, first moistened with a weak solution of 
iodine, in iodide of potassium, so as to tinge them of a dight- 
bine colour without destroying their transparency, the dilute 
sulphuric acid be applied, a very beautiful detachment of the 
lamelle will generally take place (figs. 3, 4). 

Some other effects produced by heat upon the starch granule 
may here be mentioned, as they would seem to throw addi- 
tional light upon its structure. Let potato starch be placed in a 
small quantity of water, and exposed to heat until the moment 
that the whole assumes the condition of a thick paste. Ifa 
minute portion of this paste be now removed on the point of a 
needle from the sur pface of the mass, and placed ina drop of water 
on the stage of the microscope, it will be found to consist chiefly 
of granules, on which the action of the hot water has apparently 
but just commenced. In these (figs. 5, 6) a slight enlargement 
of the entire granule has taken place, the concentric striz are 
still very visible, the central cavity has hecome much enlarged, 
and now presents several radiating offsets, which are directed 
towards the thick end of the granule, while numerous delicate 
strie may be seen passing off from the cavity in the same 
direction, and intersecting the various lamella. It is plainly 
in the course of these striz that the offsets from the cavity 
take place: these offsets are simple fissures passing through 
the lamella; and the whole structure, now described, indicates 
the existence of definite lines of cleavage at right angles with 
the lamelle. 

There is another mode of examining the starch granule 
which also tends to throw light upon its structure. By mixing 
the starch with gum-water, as originally practised by Raspail, 
and more recently by Schleiden, and allowing the mass to dry, 
we may, by means of a sharp razor, cut off very thin slices: 
these slices will contain sections of the granules passing 
through many different planes. When placed in water under 
the microscope, the cut surfaces may generally be seen to pre- 
sent, with various degrees of distinctness, a greater or smaller 
number of concentrically curved lines, each returning into 
itself. If the divided granules be weakly iodinized, and 
treated with the dilute sulphuric acid, they will swell up in 
the same way as the perfect granules, and some of the sections 
will then be seen to have opened into a large central cavity, 
rendering the vesicular nature of the swollen granule a matter 
of absolute certainty (fig. 7). 

The observations now recorded leave in my mind no doubt 
whatever of the formation of the starch granule out of a series 


DR. ALLMAN, ON THE STARCH GRANULE. 167 


of independent lamellz in the form of hollow shells included 
one within the other. Another question of importance re- 
mains to be determined, namely, whether all these lamelle are 
in every respect similar to one another, chemically and physi- 
cally, from the most external to the most internal. 

In no case can there be detected any difference between 
them in their behaviour towards iodine. All parts of the 
granule, from the circumference to the centre, appear to be 
similarly acted on by this reagent. While, however, the 
starch granule is thus most probably chemically identical, 
from its surface to its centre, there is, on the other hand, 
reason to believe that a decided physical difference exists be- 
tween the outer and the inner lamelle. 

The united action of sulphuric and acetic acid on the gra- 
nule is very remarkable, and the following experiment seems 
capable of throwing much light on this question. Let the 
granules, after being tinged of a pale blue, by a weak solution 
of iodine in iodide of potassium, be placed upon the glass 
stage, and treated, in the way described above, with the dilute 
sulphuric acid. They will immediately present the pheno- 
mena characteristic of the action of sulphuric acid, and will 
swell to many times their original size. After the action of 
the acid has continued for about a minute, let a drop of strong 
acetic acid be applied, and the whole covered with a bit of 
thin glass. On now examining the preparation under the mi- 
croscope, a remarkable change will be seen to have taken 
place. The swollen granules will continue to present a_per- 
fectly even outline, but in their interior may be seen a wrin- 
kled membrane, which has detached itself, more or less, from 
the more external parts of the granule. The granule is now, 
in fact, most distinctly seen to be a vesicle, from whose walls 
the internal structures have detached themselves. These 
structures, by the continued action of the acetic acid, become 
more and more contracted, and will at last be frequently seen 
as a small irregular mass, lying like a nucleus upon the wall 
of the vesicle, and giving to the latter almost exactly the ap- 
pearance of a nucleated cell. Figures 8, 9, 10, 11, exhibit 
different appearances of the granule under the action of the 
acetic acid, as seen in the starch of the colchicum autumnale. 

It is here plain that the corrugated membrane consists of a 
certain number of the internal lamella which have been acted 
on by the acids in a different way from what takes place in the 
external ones, and we have thus a proof of a decided difference 
between the outer and inner lamella. This difference is doubt- 
less merely physical, and probably depends on the different 
ages of the lamella. It sometimes happens that a second ap- 


168 DR. ALLMAN, ON THE STARCH GRANULE. 


plication of the acetic acid is necessary for the success of the 
experiment, and if the granules have been too long exposed to 
the action of the sulphuric acid before the application of the 
acetic, the characteristic effect cannot be produced. The ex- 
periment is most striking in its result on the small and middle- 
sized granules. Though the acetic acid is the more certain 
and decided in its action, yet a very marked distinction be- 
tween the internal and external portions of the granule will 
be frequently manifested, by the addition of cold water just 
after the action of the sulphuric acid. 

It has been already stated, that when the starch granule 
is exposed to a high heat, as in the process of roasting, 
the spot corresponding to the ‘nucleus’ of Fritzsche, becomes 
distended into a cavity of considerable size. Now, if the 
granules with the central cavity thus distended, be placed in 
water, the water will be rapidly absorbed until it fills the 
cavity; and if a drop of acetic acid be then added, the con- 
tents of the cavity will immediately assume a granular condi- 
tion, while the rest of the granule remains unaltered. The 
granules taken from the surface of the paste, already described, 
frequently exhibit a similar granular condition of the contents 
of the cavity, even without the application of any reagent. 
This granular matter is coloured blue by iodine, and its 
occurrence would seem to indicate that starch in an amorphous, 
or, at least, non-lamellar state, constitutes the proper contents 
of the nucleus of Fritzsche, which must itself be viewed as a 
minute cavity. 

It now remains to examine the phenomena presented by 
potato starch during the action of hot water, and of certain 
mineral acids, with the view of determiming whether these 
phenomena may not admit of some other explanation than 
those offered by Martin and Busk ; for if the account just given 
of the structure of the granule be the true one, these observers 
must have misinterpreted the appearances.* 

When I first repeated the experiments of Martin and Busk, 
I must confess that | became an entire believer in the theory 
of involution, so distinctly did the granules appear to develop 
themselves under the microscope by a process of unfolding. 
My adhesion was especially given to the modification of 
Martin’s views advocated by Busk, who maintains that the 
evolution of the granule consists athe in an unfolding of 
plates, or ruge, than i in the unwinding of rolls. During some 
further observations, however, on fie starch granule, certain 
facts presented jhemedives which did not admit of explanation 
in accordance with the involution theory, and I am now fully 
convinced that the phenomena presented, admit of quite a dif- 


DR. ALLMAN, ON THE STARCH GRANULE. 169 


ferent explanation from that given by the advocates of inyo- 
lution. 

I believe that the appearances, referred to a process of 
unrolling or unfolding, depend upon the different degrees of 
rapidity with which the various parts of the granule expand 
under the action of the reagents. Confining ourselves to the 
action of sulphuric acid, as being the most easily observed, 
and being in all essential points exactly the same as that of 
hot water, we shall find that the immediate action of the acid 
is to cause a swelling up of the external parts of the granule. 
Now this expansion does not take place uniformly ; and during 
the first moments of the action, a great number of delicate 
rugee may be witnessed, which generally surround the granule 
in regular and very pretty wavy rings. These ruge now 
rapidly become deeper, then fewer, larger, and more irregular, 
and then all at once disappearing, the granule has become 
greatly increased in size, and lies as a smooth, or slightly cor- 
rugated vesicle, on the object-holder of the microscope. All 
these stages go on so rapidly, that it is exceedingly difficult to 
follow them. Most of them are represented in Mr. Busk’s 
paper, and they so exactly resemble a process of unfolding of 
plice as very naturally to lead the observer to refer them ta 
such a process. It appears to me, however, quite certain, 
from repeated and careful observations, that there is no un- 
folding as a primary phenomenon, but that certain parts of 
the granule being more speedily acted on by the acid than the 
neighbouring parts, swell out into prominent ridges, leaving, 
of course, furrows and depressions between them, which, in 
their turn, respond to the action of the acid, and now unfold 
themselves from between the ridges. While the process of 
unfolding, therefore, may, to a certain extent, be viewed as 
real, it depends on a condition which is only a secondary phe- 
nomenon, belonging exclusively to the granule after it has 
undergone certain alterations induced by the action of the 
acid. 

The appearances just described are best seen in the larger 
granules : in the smaller ones, the well-developed and regular 
rugz, which, in the larger, show themselves during the first 
moments of the action of the acid, are not generally produced ; 
but immediately after the application of the acid, the smaller 
granules will for the most part be seen to present, in one spot, 
a deep depression, caused by the more rapid distension of the 
surrounding parts ; and this depression itself, receiving imme- 
diately afterwards the full action of the acid, will roll out- 
wards, and become more and more shallow as the granule 
continues to expand, while the latter, after passing through a 


170 DR. ALLMAN, ON THE STARCH GRANULE. 


series of figures, which may be compared to watch-glasses of 
various depths, will ultimately lie as a smooth spherical 
vesicle on the stage of the microscope. This is the simplest 
case of the phenomenon under consideration ; and as it is well 
adapted to illustrate its real nature, | have given a series of 
figures, semi-diagramatic, of the successive stages of the pro- 
cess (figs. 12—17). 

The view now taken is entirely borne out by the fact that 
when the sulphuric acid is applied so dilute that its action on 
the granule is very slow, or when the granule, by the prolonged 
action of iodine, has become less sensitive to the operation of 
the acid, a gradual swelling of the whole granule, without any 
appearance of plice, may be witnessed. But a fact, which 
appears to me at once fatal to the involution theory, is the 
following :—the larger granules may easily be crushed by 
slight pressure between two slips of glass, and if the pressure 
has not been too great, it will then be seen that many of the gra- 
nules present deep fissures, opening upon the surface, and 
thence radiating towards the centre. Now, when these granules 
are treated with sulphuric acid, the fissures will be found in the 
swollen granule to retain exactly their original position and 
continuity, whereas it is evident that if they had been formed 
in a membrane rolled up in accordance with the theory of 
Martin, or even deeply plicated, as maintained by Busk, each 
would now present itself in the unfolded granule as a series of 
interrupted slits ; unless, indeed, it had passed through the 
whole thickness of the involutions, a circumstance which, 
though it may possibly be allowed of some of the fissures, 
cannot be admitted of all. 

A subject of much importance in the physiology of the 
starch granule, and of especial interest in its bearing upon the 
very difficult question of the genesis of this body, is the order 
of deposition of the lamella. Whether are the new lamellee 
deposited on the inner or on the outer surface of those pre- 
viously existing ? 

The data we possess, for coming to a satisfactory conclusion 
on this point, are at present very imperfect. It appears to 
me, however, that the structure of the granules, as attempted 
to be demonstrated in the present paper, is more in accordance 
with the centripetal than with the centrifugal order of deposi- 
tion. It will be recollected that while the external lamelle 
resist the action of certain reagents, the internal easily yield to 
them ; now, since there appears to be no difference in chemical 
constitution between any of the layers, we can only attribute 
this difference in the behaviour of the layers to a less degree 
of solidity in the internal ones, a condition which is most 


DR. ALLMAN, ON THE STARCH GRANULE. 171 


easily explained by supposing these to be of more recent depo- 
sition. When we consider, moreover, the probability that the 
central cavity contains starch in a fluid or amorphous condition, 
the weight of evidence appears so far in favour of the gradually- 
increasing growth of the granule from the circumference to- 
wards the centre. But there is another strong argument in 
favour of this view—the behaviour of the small granules under 
the united action of sulphuric and acetic acid is in all 
essential particulars precisely the same as that of the larger 
ones. Now no one will deny that the small granules are, for 
the most part, at least, only a young state of the larger ones ; 
and it would therefore follow, if the centrifugal theory were 
the true one, that the external layers of these young granules, 
after becoming internal by the deposition of new layers on the 
outside of them, had lost their original physical characters, 
and were no longer able to offer the same kind of resistance as 
formerly to the action of the reagents, a circumstance which 
seems so improbable, that it cannot be admitted without fur- 
ther proof. 

It will be stated in opposition to the theory of centri- 
petal growth, that this would require the constant distension 
of all the layers which lie external to the new ones. This 
objection, however, appears to have but little weight; we 
have already seen the great distensibility of the lamella under 
the action of hot water, mineral acids, and other reagents ; 
and there is no reason to suppose that the very slow disten- 
sion which the centrifugal deposition would require, may not 
take place while the granule is contained in the cells of the. 
living plant, and surrounded and permeated by the fluids of 
the cell. That the lamellae admit of rapid imbibition of fluid 
is evident from the phenomena already described as occurring 
when the granule is plunged into water, after being exposed 
to an elevated temperature until its central cavity becomes 
distended, without the exposure being sufficient to effect a 
chemical change; and even in granules which have been 
simply dried at a low temperature, a marked increase of size 
may be observed when they are moistened with water. 

An observation originally made by Fritzsche of the occa- 
sional occurrence of a compound granule, consisting of two or 
more simple granules, each with its own lamella and so-called 
nucleus, but the whole surrounded by common lamella, would 
seem at first to decide the point in favour of the external 
deposition of the new layers. It is obvious, however, that 
the appearance presented by these abnormal granules may be 
just as well explained by supposing the granule, originally 
single, to have gone on up to a certain time forming layers in 


172 DR. ALLMAN, ON THE STARCH GRANULE. 


the ordinary way, and that subsequently in the interior of the 
granule, by some abnormal influence, two centres of deposi- 
tion took the place of the original single one. 

The growth of the granule may be probably thus ex- 
plained: the materials for its growth are absorbed from the 
surrounding cell contents through the previously existing 
lamella, and thus conveyed into the central cavity. ‘The con- 
tents of this cavity are fluid or amorphous; and the perfect 
amylum is subsequently deposited from them in layers on 
the walls, each layer pushing outwards those which had pre- 
ceded it. It is true that this only attempts to explain the 
growth of the granule, its origin is still unaccounted for, and 
must remain so till increased light is thrown by new observa- 
tions on this difficult question. 

From the facts mentioned in the present paper the following 
conclusions would seem to follow :— 

1. That the starch granule consists of a series of lamella in 
the form of closed hollow shells, included one within the 
other, the most internal enclosing a minute cavity filled with 
amorphous (?) amylum; that the concentric striz visible in 
the granule indicate the surfaces of contact of these lamelle ; 
and that the so-called nucleus of Fritzsche corresponds to the 
central cavity. 

2. That while the lamellze appear to be all identical in 
chemical constitution, yet the internal differ from the external 
in consistency or other conditions of integration. 

3. That the order of deposition of the lamellz is centri- 
petal. 

4. That while the starch granule is thus a lamellated 
vesicle, it cannot be included in the category of the true vege- 
table cell, from which it differs not only in the absence of a 
proper nucleus,* but in presenting no chemical differentiation 
between membrane and contents. 


* Unless the obscure indications of such a body as recorded by Busk, 
in the memoir quoted, p. 68, may be conceived to afford evidence of its 
presence. 


CPE? 


TRANSLATIONS, &c. 


On the DeveLorMENT of Srarcu. By H. Crier. (Abstracted 
from the ‘ Botanisch. Zeitung.’) January 20th, 1854. 


Tue following observations, the result of lengthened investiga- 
tions, relate principally to the history of the development of 
the starch granule, a subject which appears to have been, 
hitherto, but little studied. ' 

Among the different kinds of starch which occur in larger 
quantity, spherical granules with a central nucleus are the 
most rare, whilst this form is the most abundant in the vege- 
tating parenchyma, in the bark, and in the medulla. In these 
situations the starch grains are seldom met with of any con- 
siderable size; it appears and disappears with equal rapidity, 
but when it occurs in these parts of a more remarkable form 
and greater size, it affords very instructive information, as will 
be seen below. 

Although, speaking generally, no systematic characters are 
afforded by starch, certain peculiarities, nevertheless, pervade 
most plants in one and the same family. Thus, all the Ferns 
examined by the author, present a clouded, indistinctly-lami- 
nated, irregular form of starch-granule; all the Cyperacea, a 
compressed granule, with large hollow nucleus, &c. Excep- 
tions, in this respect, however, exist ; the Aroidez, for instance, 
exhibiting every variety of form, except the compressed. 
Moreover, the various forms occasionally pass one into the 
other, so that cases occur in which it is impossible to say to 
which category the plant belongs. 

The cross of polarization always passes through the nucleus 
of the granule, and is apparent in all positions of the latter; as, 
for instance, even when a flattened granule is placed on the 
edge, as in fig. 1, d (Plate VII.) The phenomena exhibited 
under polarized light depend upon the amine ; and the cross 
remains the same, whether the granule be hollow or appa- 
rently solid, except that in the former case the centre is 
wanting, The author adopts the view that the amine must 
be regarded as surrounding the whole granule. Practically it 
is difficult to prove this, although it is found that, in starch 
having an excentric nucleus, the lamine immediately around 
the nucleus are of uniform thickness throughout, whilst the 
more exterior amine become thicker and thicker in one direc- 
tion. Besides which, it may be remarked that, strictly speak- 


174 CRUGER, ON THE DEVELOPMENT OF STARCH. 


ing, the transverse stri@, presented in some kinds of starch, 
never actually reach the border of the granule, but are thence 
curved towards the nucleus. The tenuity of one side of the 
lamine, in this case, appears to exceed the powers of our pre- 
sent instruments. 

Where the /amine are very irregularly deposited, one or 
more additional branches are superadded to the four rays con- 
stituting the cross of polarization. 

With respect to the development of starch, the author states 
that, according to Mohl’s Essay on ‘The Vegetable Cell,’ which 
contains the most recent résumé he is acquainted with upon 
the subject, the development of starch is unknown. 

It may be regarded as a fact, which, by the concurrent ob- 
servations of our best writers, has gradually assumed the form 
of an empirical law, “that all new formation in the plant 
proceeds under mediation of the protein substances.” The 
author’s investigations on the subject of starch have served to 
confirm this law. 

One of the difficulties in the study of the development of 
starch, resides in the circumstance that it is such a loose 
secretion of the plant-cell. In the majority of cells contain- 
ing starch, large and small, separate and aggregated, granules 
occur, apparently representing all stages of growth, but with- 
out its being possible to demonstrate this; as well as others 
in progress of solution, In order to facilitate his labour, and 
thus to attatm a more certain guarantee for his results, the 
author felt it necessary to look out for plants im which the 
granules were not too numerous in the cells, and in which 
also, in the green cellular tissue, the formation of distinct and 
thick Jamine in the starch might be observed. Plants of this 
kind are afforded in various species of Costus, in Canna, 
Dieffenbachia seguina, and Philodendrum grandifolium (?). 
For the study of the compound starch, he found Batatas 
edulis the most convenient, although other plants, for instance, 
Carolinea princeps, would, perhaps, have been more so. 

It was first requisite to determine whether Schleiden’s 
opinion, according to which the outer lamine of the starch 
granule are the young er orthe last formed, was correct ; 
which turned out to be the case. But this answered only 
half the question which the author had proposed to himself ; 
the other was: Where and how are the outer damine formed ? 
In Mohl’s paper, ‘On the Anatomical Relations of Chlo- 
rophyll’ (Verm. Schrift. p. 349), he found indications upon 
this point which were followed up. Mohl shows that chloro- 
phyll and amylum almost always occur associated together, 
and, moreover, that the chlorophyll appears before the amylum. 


CRUGER, ON THE DEVELOPMENT OF STARCH. 175 


Schleiden assumes the existence of colourless chlorophyll, on 
what grounds the author is ignorant, to whom the fact appears 
to be this:—the protoplasma, that menstruum universale, that 
tinctura vitalis of the plant, acquires a green colour, under the 
influence of light, owing to the formation of a resinous 
material, which may be extracted by ether, &c., but without 
losing its other properties, which relate to the life of the 
plant, and the solution and formation of other substances. 

The author regards this mucus, the protoplasma, as identical 
with Mohl’s primordial sac. He has looked for the latter for 
several years without being able to find it. Neither by alcohol 
nor by acids has he ever been able, satisfactorily, to demon- 
strate the existence of any membrane in the interior of the 
cell. “ When a cell from the parenchyma of a ripe or nearly 
ripe fruit, e.9., of Mangifera, Carica papaya, after it has been 
treated with alcohol or acids, is placed under the microscope, 
the matter at first appears quite clear, and a membrane sur- 
rounding the coagulum, in the interior of the cell, seems to be 
distinctly visible. But when an attempt is made, with the 
needle, to render the supposed sac tangible, the thing assumes 
quite a different aspect. The whole is resolved into mucous 
filaments, or the like, and the sac disappears like a phantom. 
[ have made similar experiments in the cells of the paren- 
chyma, in the vegetating parts of Cactus, and other plants, re- 
commended by Mobl, for the exhibition of the “ primordial 
sac.” 

The species or variety of Canna, which is cultivated in 
Trinidad for the seeds, is distinguished from the other variety 
yielding the “toloman,” or “ canna-starch,” by the circum- 
stance that, in the cells of the rhizome, only a few, but very 
large, starch granules, with distinct andnumerous lamina, are 
developed. 

Two species of Costus, C. spiralis and C. comosus (?), contain 
long cylindrical, strongly-laminated granules of starch in the 
cells surrounding the vascular bundles, and in that situation 
in small number; whilst in the rhizome all the cells are 
crammed full of starch. 

Philodendrum grandifolium and Dieffenbachia  seguina 
present, in all parts of the stem, starch granules with well- 
marked lamine and of very unusual forms, some being 
branched. 

In all these plants the younger cells contain only spherical 
starch granules; and it cannot be doubted that the other 
forms, met with in the older cells, derive their shapes merely 
from the mode in which the later amine are deposited around 
the originally spherical granule. Consequently, also, the 


176 CRUGER, ON THE DEVELOPMENT OF STARCH. 


minute spherical granules which occur in the older cells, to- 
gether with the larger irregularly-shaped ones, represent 
nothing more than lower stages of development. 

Ail starch occurs seated upon the layer of protoplasma, 
lining the inner wall of the cell, so long as the latter is 
capable of further development, and so long as protoplasma 
continues to exist in the cell. In every kind of starch in 
which the damine are distinctly formed, and in which an ex- 
centric and distinct nucleus exists, it may be remarked that 
the nucleus is always situated at the point most remote from 
that by which the granule is attached. This is readily ob- 
servable in all cases in which there are not too many granules 
in a cell, and where the cells of the tissue are sufficiently 
large and transparent to allow of one or a few layers being 
observed at once. The elongated cells, surrounding the vas- 
cular bundles in the species of Costus above adverted to, are 
eminently fitted for this object ; but when once the observer is 
satisfied of the truth of the statement, he will find it suffi- 
ciently confirmed in other plants where the observation is not 
so readily made. Consequently, in uninjured cells, the starch 
granules are found free only when they are old and the proto- 
plasma has (entirely ?) disappeared from the cell, whether the 
latter be more or less filled with the starch. In this case, one 
granule by its development appears to detach the other from 
the wall of the cell. 

Now, if cells containing starch advanced just beyond the 
lowest stage of development in one of the above-mentioned 
plants are examined, it will be found that the granule, at the 
end by which it is attached to the protoplasm or chlorophyll, 
usually presents a layer of substance optically distinct from 
the latter, and from the bulk of the starch granule itself. If 
the preparation be treated with iodine, it will be observed 
that this outermost layer of the starch granule is not coloured 
blue, but, at the same time, that it does not so rapidly assume 
a brown or yellow colour, or so deep a tint as the protoplasm 
and chlorophyll. All granules of young starch do not present 
this layer of the same thickness-—in some it being more, and 
in others less developed ; and in many it is so thin as to be 
visible only with difficulty, and not distinguishable without 
trouble from the lines produced by the diffraction of light at 
the border of the starch granule. This circumstance has 
chiefly been the cause, perhaps, why it has not been previously 
remarked in those kinds of starch in which the lamin@ are 
deposited with tolerable uniformity on all sides. It should 
be studied in plants in which thick and excentric lamine@ exist 
in the starch grain. 


CRUGER, ON THE DEVELOPMENT OF STARCH. 177 


The author regards this layer as a substance on the point 
of conyersion into starch, but which, as yet, does not possess 
the property of becoming blue on the addition of iodine, and 
still contains, moreover, nitrogen or a protein substance. He 
adduces the following reasons for this conclusion :—When 
young starch is treated with iodine it does not acquire so pure 
a blue colour, nor nearly so rapidly as it does when older ; 
and minute granules, which, without the reagent are optically 
indistinguishable from starch grains, are either only coloured 
yellow or remain uncoloured. It is known that starch is 
coloured reddish by Millon’s reagent. 

The above particulars being satisfactorily made out, the 
varying thickness of the layers in different granules is readily 
explicable. The layer of substance, which is destined imme- 
diately to become starch, is at first gradually formed from the 
protoplasm, and is not transformed into starch until it has 
acquired a certain thickness. In this process, also, accidental 
and individual diversities may occur, inasmuch as the completed 
starch granules present nothing like perfect uniformity. 

Now, what is this transitionary substance? Is it znulin ? 
The little correspondence in the results of analyses appears to 
indicate that inulin itself is a complex substance; does it 
really contain no nitrogen? ‘The transitionary material does 
not appear to be gum, as it is not seen to dissolve in water, 
even after prolonged maceration. Does it contain nitrogen in 
chemical combination, or only a protein substance, as an 
element? These are interesting questions which offer them- 
selves, and which will probably not be very soon answered. 

In Batatas edulis, the author has investigated the develop- 
ment of the so-termed “ compound starch-granule.” The 
origin of this form of starch has been sought in the breaking-up 
of the grain into smaller granules ; and this opinion has been 
supported by the observation of granules presenting a fissure 
in the middle and a nucleus at each end, and having external 
lamine surrounding the whole, an instance of which kind is 
shown in fig. 3, 0. 

From the examination of the starch in the cells of the very 
young stem of Batatas edulis, the author concludes that the 
constituent portions of the compound starch granules are all 
originally distinct, coalescing into the larger compound grain 
after the disappearance of the transitionary substance above 
described. 

The development of the incised discs or nodular rods which 
are found in the Euphorbia, in the proper vessels, as they are 
termed, so far corresponds with what has been stated above, 
that the granules in the young condition are also spherical. 

VOL, I. 0 


178 KOLLIKER, ON THE NUCLEAR FIBRES, &c. 


The author has been unable to perceive /amine, or transition- 
ary substance in these corpuscles, nor any cross of polariza- 
tion. Moreover, from its reaction with iodine, he regards this 
starch as a substance distinct from all other kinds. 

It appears to him that starch in general is very far from 
being a homogeneous substance. Besides the various density 
of the lamine, the nucleus frequently encloses a substance 
which, undoubtedly, differs in more than in optical properties 
from the rest of the granule. That the lamine, even the 
innermost, in passing from the fluid to the solid condition,— 
a sort of crystallization,—may include foreign materials, is by 
no means inconceivable, and it is even probable that the in- 
cluded substance may again be removed from the perfect 
grain. 

The author then proceeds to show that what he has observed 
corresponds, in the main, with Schleiden’s statements, and to 
remark in strong terms upon the views of Kiitzing, who con- 
siders the starch grain in the light of a cell. 


The figures here given are selected from the more numerous 
ones accompanying H. Criiger’s paper, but will be found 
sufficient to illustrate all essential points in this disquisition, 
which, so far as it extends, is undoubtedly a valuable contri- 
bution to our knowledge of starch, and especially of its genesis 
—a point which, since the discovery of the existence of that 
principle, or one closely allied to it in various tissues of ani- 
mals, is more than ever deserving of investigation. 


On the DeveLtorMeEnt of the so-called ‘“‘ NucLeaR Fipres,” of 
the “ Exvastic Freres,” and of the “ Connective Tissue.” 
By A. Kéttrker. From the ‘ Verhand. d. Physik, Medicin. 
Gesselsch. in Wiirzburg.’ Vol. iii., P. 1, p. 1. 1852. 


1. Elastic Tissue-—The view quite recently propounded by 
Virchow and Donders, that the so-termed nuclear fibres are 
developed not from nuclez but from cells, is perfectly correct ; 
but at the same time I cannot agree with these authors in regard- 
ing all the fusiform cells which occur in embryonic connective 
tissue, and which have been previously variously described, as 
formative cells of the nuclear fibres, and in their denial of the 
development of connective tissue from cells. Only the 
smaller proportion of these fusiform cells have any relation to 
the nuclear fibres, and they are readily distinguished from the 
formative cells of connective tissue by their shortness, their 
dark borders, their fine prolonged extremities, which never 


KOLLIKER, ON THE NUCLEAR FIBRES, &c. 179 


form a bundle of fibres, and their elongated, rodlike nucleus. 
Many of these cells also present, not merely 2, but 3, 6, or 
more delicate processes, when, without losing their elongated 
general form, they exhibit the aspect of nucleiform cells. 
In every situation where nuclear fibres subsequently occur, 
these cells are met with, in embryos, at four months or even 
earlier, and, in the tendons, ligaments, and fascia, still readily 
admitting of being isolated, in the second half of feetal life; 
and it is extremely easy to show that they form the so-termed 
“nuclear fibres” and “nuclear fibre reticulated tissue,” by 
the coalescence of their two or more numerous processes. 
In very many places, as in the perimysium, the external 
integument, the mucous membranes, fasciz, fibrous mem- 
branes, all traces of the original composition from cells is 
lost, and the so-called nuclear fibres, which I term fine elastic 
Jibres, darstella, the well-known, everywhere uniformly wide, 
solid fascie or fibrous reticulations ; whilst in other situations 
the original enlargements of the cells remain more or less 
manifest, as occasionally in the fascie and ligaments, and 
especially in the cornea. In these cases a certain relation to 
the nutrition of the organs composed of connective tissue, con- 
cerned, may be ascribed to the remains of the cell cavities, 
though, at the same time, it appears to me that it is going too 
far when Virchow at once represents the nuclear fibres as a 
system of cavities in the connective tissue subservient to 
nutrition. Moreover the nuclei of their formative cells also 
take part in the formation of the nuclear fibres, and indeed 
frequently not altogether an unessential one, becoming trans- 
formed when the cells coalesce into elongated rod-like cor- 
puscles, in the neighbourhood of which the other parts of the 
cell are occasionally more retracted. What is true of the 
nuclear fibres applies also to the common elustic tissue. 1 
showed, several years since, that in every situation where 
elastic tissue exists in the adult, only nuclear fibres are present 
in the infant at birth ; that consequently these two elementary 
forms are connected, and the elastic fibres are developed from 
a widening out of the nuclear fibres, which holds good also 
for the elastic and fenestrated membranes, which are nothing 
but metamorphosed elastic networks. This correspondence 
in itself is necessarily almost sufficient to show, beyond doubt, 
that the elastic fibres also proceed from cells; but that this is 
the case is also shown by direct observation, in the lig-nuche, 
in the arteries, and the superficial fascia of the abdomen, in 
which situations the origin of primarily fine elastic fibres, 
from fusiform cells, is everywhere pretty easy to be seen. 

2. The connective tissue, in its two principal forms—the 


o 2 


L80 KOLLIKER, ON THE NUCLEAR FIBRES, &c. 


close and the /ar—is developed in a somewhat different manner. 
The lax connective tissue, as it occurs for instance in the sub- 
cutaneous and submucous tissue, and in the large cavities 
around the viscera, appears first in the embryo, in the form 
of a transparent, soft, gelatinous substance. ‘This consists 
essentially of fusiform, or stellate anastomosing cells, and of 
a semi-fluid, clear pulp, lodged in the interstices of the cel- 
lular network, but contains besides, in the latter, a certain 
number of rounded cells of no definite character. I first 
observed this gelatinous connective tissue in the substance 
which is found between the amnios and the chorion, and at 
first paid attention only to the anastomosing stellate cells, 
which I denominated as “ reticular connective tissue.” 

Subsequently I met with the same gelatinous tissue in the 
enamel organ, and in this situation ascertained the presence 
of a considerable quantity of albwmen and mucus, in the gela- 
tinous substance, whilst at the same time Professor Virchow 
described the Whartonian pulp as of the same nature, and 
also discovered mucus in it. Upon farther pursuit of the 
subject, it was soon obvious that gelatinous tissue of this kind, 
which, moreover, Schwann had already briefly described, from 
the orbit of a foetus, are very extensively distributed; in a 
word, as has been already remarked, as a precursor to all large 
masses of lax connective tissue without exception, and that its 
further development everywhere proceeds in essentially the 
same way, which is as follows:—The network of stellate cells 
becomes gradually more and more close, whilst new cells which 
arise in the gelatinous substance are continually joined to it, 
and at the same time the reticulations are gradually converted 
into bundles of fibres, which ultimately differ in no respect 
from the common lax fasciculi of connective tissue. Whilst 
this is proceeding, the pulpy substance is constantly consumed, 
serving as it does as a cytoblastema for the formation of the 
cells, which go through a varied course of development, accord- 
ing to the various situations in which they are placed. Some 
of them, in the way already indicated, pass into connective 
tissue, others unite together, and are transformed into fine 
elastic fibres, blood-vessels, and nerves, the majority lastly 
produce within themselves and become fat-cells. 

Thus, from the gelatiniform embryonic connective tissue 
ultimately arises either common adipose tissue, or rather lax- 
connective tissue, not containing fat. It is not, however, in 
saying this, intended to be implied that the gelatiniform con- 
nective tissue must necessarily go through these series of de- 
velopment; on the contrary, it is much more disposed to 
remain in a condition more or less allied to its original one. 


KOLLIKER, ON THE NUCLEAR FIBRES, &e. 181 


Thus, in the Whartonian pulp, even in the mature embryo, 
we may always notice, still partially remaining, more unde- 
veloped bands of connective tissue with an abundance of pulp 
between them. Virchow has described this as a special 
tissue, under the term of ‘‘mucous-tissue.’ I am not, how- 
ever, able to perceive in it anything more than immature lax, 
or gelatinous connective tissue, and believe that, notwith- 
standing the presence of much mucus, the impossibility, by 
boiling, of obtaining gelatine from it (Scherer), and the ab- 
sence of distinct fibrils, there is no reason to distinguish it 
from connective tissue; for, in the first place, as we have 
seen, all embryonic, lax-connective tissue contains abundance 
of mucus; and, secondly, as has been ascertained by Scherer, 
always at first affords no gelatine; and, thirdly, also at first 
presents no distinct fibrils, which, moreover, are very manifest 
in the Whartonian pulp in many situations. Although, there- 
fore, I cannot regard this pulp as anything but an embryonic 
gelatinous connective tissue, [ am not disposed to assert, that 
every reticulated tissue is at once to be considered as such, 
much rather is it very conceivable that, besides the cellular 
networks, which are conyerted into connective and elastic 
tissue, other kinds exist. As such, I would just indicate the 
reticulations formed of pigment cells in the choroid coat and 
in the batrachia, the former of which also occur without pig- 
ment, constituting a pale, fibrous network, which differs in its 
chemical relations from connective tissue. As these networks 
occur in the adult, neither they nor the networks which re- 
semble them in general can longer be referred to the lax form 
of connective tissue, however much they may resemble the 
embryonic forms of that tissue. 

The solid connective tissue of the tendons, ligaments, &c., is 
formed, as was stated by Schwann, solely and exclusively out 
of cells, without any perceptible connecting substance. If 
the tendons of very young embryos are examined, nothing is 
found in them but fusiform cells, some of which have refer- 
ence to the formation of the elastic fibres of these organs, 
whilst others constitute connective tissue. The latter are 
considerably larger and paler than the formative cells of the 
elastic fibres, contain larger oval nuclei, and present, when 
they have attained only a slight increase in length, an undu- 
lated prolongation of their enlarged extremities, a fibrillar 
formation, which is constantly more and more distinct. When 
these cells, which in various animals may be isolated, not 
without some difficulty, have reached a certain completion, 
they coalesce by their extremities, and form long cylindrical 
fibres, which continue for some time to exhibit the original 


182 KOLLIKER, ON THE NUCLEAR FIBRES, &c. 


cell-bodies and nuclei, but subsequently are transformed into 
uniform non-nucleated fibres, which soon exhibit their fibrils 
with equal distinctness, as the perfect fasciculi of connective 
tissue. The bundles of connective tissue, which are at first 
very slender (0:002’”), attain their final completion by a con- 
tinual growth in thickness and length, until at last the tendons, 
after their elastic elements are also completed, no longer pre- 
sent any traces of the embryonic conditions. The other 
forms of solid connéctive tissue are constituted in precisely 
the same way as the tendons, and in no portion of them does 
the intercellular substance play any important part. 

From the facts above stated, it is obvious that it is impos- 
sible to comprise the connective tissue with that> of cartilage, 
as was proposed first by Reichert. Although in many cases 
the cartilages have a fibrous, collagenous matrix, it does not 
follow that they should have any nearer relationship, because 
the matrix of the cartilages differs entirely, genestically, from 
the fibrous substance of connective tissue, and is not developed 
From cells. Besides this, such a matrix is even necessary to 
the constitution of the cartilaginous tissue, seeing that in the 
reticular cartilages it is not collagenous, and in many cartilages 
(Chorda dorsalis, gill rays of many fishes, aural cartilage of 
certain mammalia) may even be wholly wanting. It is true, 
nevertheless, that a certain parallel may be drawn (as Virchow 
has done) between the cartilage-cells and the so-called forma- 
tive cells, because (as I have already stated, before the 
development of nuclear fibres from cells was known) in many 
situations (particularly distinct in fibro-cartilages and where 
fibrous parts adjoin cartilage) cells, which can scarcely be dis- 
tinguished from cartilage cells, pass into nuclear fibres. This 
resemblance, however, is imperfect, since the common forma- 
tive cells of the elastic fibres do not resemble cartilage-cells 
more than do any other cells of embryos, and in the situations 
noticed depends more upon an analogous arrangement and 
grouping of the cells, and on the absence of definite characters 
in the boundary lines between the tissues in question. If 
connective tissue be compared with bone, it is quite necessary 
to distinguish between bones ossified out of cartilage and those 
which are formed from a soft blastema. The former can be 
regarded just as little as the cartilages, as analogous to the 
connective tissue, whilst with respect to the latter the whole 
question depends upon the histological position which is 
assigned to the ossific blastema. If the fibrous part of it, as I 
think I have observed, be really developed out of fusiform, 
coalesced cells, it may be regarded as a kind of immature 
connective tissue, in which case the compact bone-substance 


KOLLIKER, ON THE NUCLEAR FIBRES, &c. 183 


which arises from a tissue of this last ranks, as far as its 
matrix is concerned, in the connective tissue, although it does 
not approximate so closely to it as the spongy bone-substance 
does to the true cartilage, since its cellular elements, or the 
bone-cells, proceed from common indifferent formative cells 
by a thickening of their walls, together with a formation of 
bone canals, and can in no respect be compared with the 
so termed nuclear fibres of the connective tissue. 

This consideration, when further regarded, leads to the con- 
viction, that in the comparison of the tissues, isolated par- 
ticulars alone are insufficient for the entire history of their 
development. However much many of them in their com- 
pleted condition may resemble each other, so that, with the 
means we have at our disposal, they cannot be distinguished ; 
still it may not be possible to identify them, if their develop- 
ment has taken place in a different mode. Thus, the common 
fibrous connective tissue, which is formed from fusiform cells, 
is not identical with fibrine which has become fibrillated, or 
a minutely fibrous matrix in cartilage, and although all three 
appear nevertheless to be chemically so much alike. Just 
as little is an elastic network arising in a physiological way 
from fusiform cells, or an elastic membrane, the same as an 
elastic coat arising from a fibrinous exudation, or an elastic 
membrana propria formed by a secretion from cells, or the 
elastic basis of a reticular cartilage; and the same applies to 
osseous tissue, which has proceeded from true cartilage, fibro- 
cartilage (connective tissue with cartilage cells), a soft blastema 
(immature connective tissue with ossifying cells), or from 
organized fibrine with stellate cells—although in all these cases 
it presents no considerable differences. 

For a proper comprehension of the tissues, it is above all 
things requisite to place together those which agree, in all 
respects, in their genesis, form, chemical composition and 
function, such as the transversely striated muscular fibres, 
medullated nerve-tubes, the formed connective tissue, and the true 
cartilages. To these succeed those which, alike at the com- 
mencement of their development, afterwards separate, some 
proceeding further in their metamorphoses than the others. 
Examples of this kind may be seen in the non-meduillated and 
medullated nerve-tubes, the transversely striated and non-striated 
muscular fibres, and the muscular fascicul: of the lower ani- 
mals, which correspond genetically with the former, the true 
and the reticular cartilage, the true cartilage and sponyy tissue 
of bone, the elastic networks and elastic membranes. Where 
the genesis differs, but the after form or function, or the che- 
mical condition, is each or all of them alike, the tissues may, 


184 KOLLIKER, ON THE NUCLEAR FIBRES, &c. 


perhaps, be placed together, and in certain respects be regarded 
as coequal, though never as identical, Thus all collagenous 
tissues may be placed together; and also the contractile fibres 
containing protein, the elastic reticulated membranes, the eal- 
cified tissues with canalicular systems, all fibrous connective 
tissues; but notwithstanding, by this a perfect histological 
correspondence is by no means expressed any more than is a 
morphological identity, when organs, such as lungs and gills, 
the jaw of a mammal with that of a ray, the wing of a bird 
with that of an insect, are compared from a physiological point 
of view or from that of the anatomy of the parts when com- 
pleted. That such associations of the tissues are to a certain 
extent justifiable, and even demanded by the requirements of 
physiology, pathological anatomy, and organic chemistry, is, 
moreover, at once intelligible ; and I here only expressly add, 
in order to make myself plainly understood, that I have 
regarded the genetic point of view as sufficient for a pure 
anatomical conception, but not as alone holding good under all 
relations and respects. 

Besides this it also may be remarked, that it is quite pos- 
sible that, in many situations in which our views and notions 
at present render distinctions in the genesis necessary, perhaps 
at a future time connecting links may appear and upset all 
our systems. Thus I believe I am not wrong even now in 
describing the connective and elastic tissues as belonging to 
those between which transitions exist, and also the smooth and 
transversely striped muscular tissue, the latter in as far as it 
also affords isolated transversely striped muscle-cells. Perhaps 
even, hereafter, a contractile connective tissue in an improved 
form will be discovered as a connecting link between muscle 
and connective tissue. Such and other possibilities cannot 
seem strange to any one who knows that formative cells of the 
same kind are the initial points of the most important physio- 
logical organizations ; that consequently all tissues are, in the 
beginning, alike. We shall even ultimately be inclined, when 
we consider the substance which is present before the other 
cells, and the frequently less distinct manifestation of the cells 
in embryonic and pathological tissues, not to set up between 
the parts developed from cells and mucoid substances such an 
insurmountable limit as may appear to exist in the eyes of 
many. 


(0VEB5S?) 


Contributions to the Knowledge of Curanrous Diseases, caused 
by Parasitic Growths. By Dr. B. Guppen, From _ the 
‘ Archiv fiir Physiolog. Heilkunde v. Vierordt.’ 1853. 
Part III., p. 496. Pl. 2, fig. 1. 


(Continued from p. 33.) 
Il. Pityriasis versicolor. 


Bateman, following Willan, describes four species under the 
genus Pityriasis, two of which, P. capitis and P. rubra, vary- 
ing according to their seat, consist merely in a morbidly 
increased formation of the epidermis ; P. nigra is unknown to 
the author, but P. versicolor, as was first noticed by Eichstadt 
in Froriep’s Notizen, 1846, depends upon a parasitic vegetable 
growth. 

Pityriasis versicolor is an affection pretty widely distributed, 
and is especially common among the poorer classes ; but is also 
met with among those whose means allow them to enjoy the 
most luxurious cleanliness. ‘The author has met with it fre- 
quently in men, and, relatively speaking, more rarely in women, 
but never in children. Its more common seat is on the trunk, 
and especially on the chest. In a young man, whose chest was 
habitually exposed, the middle of it was tolerably exempt 
from the affection. 

The spots of this eruption are of a dirty-yellow colour, 
roundish, and usually of small size, or, from the coalescence of 
several together, more or less irregular, and varying very much 
in dimension. They are scarcely raised above the level of the 
skin, the elevation being perceptible only to the touch. Their 
surface is smooth ; but as the affection progresses, it becomes 
rough, and scales off in no slight extent in a whitish scurf. 
When the surface of the spot is peeled off, which is readily 
done, that which is exposed is more or less moist. 

Generally the minute round spots do not scale off: they are 
smooth, and with very few exceptions, are perforated in the 
centre by a hair. 

To examine the nature of the disease, the cuticle, from 
a part of the skin presenting a good many of these spots, 
should be raised by means of a vesicant, and the bladder 
removed as soon as possible. The portion of cuticle must be 
spread out in the most suitable manner, upon a glass plate, 
lying upon a dark ground, and the soft layer on its under sur- 
face infiltrated with serum, removed by means of a hair-pencil. 
With care this is readily effected, and nothing is left but the 
superficial, thin, transparent, firm layer, together with the hair- 
sheaths. In it, viewed from below, are seen, quite uninjured, 


186 GUDDEN, ON CUTANEOUS DISEASES. 


the foreign, whitish-yellow structures with the utmost distinct- 
ness, and in the centre of almost each rises the whitish conical 
radical hair-sheath. 

At the same time, upon closer examination, a multitude of 
extremely minute points are visible, which appear whitish by 
direct, and opaque by transmitted light. These are the open- 
ings of the sweat-ducts. Under the microscope they are seen 
to be composed of thick, flat, closely-approximated, more or 
less vertical, much-developed epidermis cells, containing yellow 
pigmentary matter; and in order not to have to refer to them 
again in the description of the fungous growth, the author here 
remarks, that they are very resistant, and remain almost wholly 
unchanged in the midst of the parasitic growth. Consequently, 
in the microscopic investigation of the fungous expansion, 
these orifices are seen enclosed in it, as opaque, usually 
brownish-yellow, infundibuliform depressions. The spores 
of the fungus are not unfrequently produced in great number 
around their border, whilst the cavity itself seems to be less 
favourable to their development, and is usually found to be 
unoccupied by them. 

In the above-described mode of preparing the epidermis, the 
layers removed may be readily submitted to investigation. 
Their cells—and this is a point upon which, as in Porrigo, the 
author lays stress—present no abnormal conditions whatever. 
The same may be said, and it is convenient here to notice the 
fact, of the undermost layers of the hard, horny epzdermis which 
are at all times free from the fungus. 

The author now proceeds to the microscopic examination of 
the spots themselves. 

If a spot together with the portion of cuticle immediately 
surrounding it be cut out of the prepared epidermis, and 
placed under the microscope, and viewed, first from below 
and then from above, it is evident, in the first place, that 
it lies in the uppermost portion of the horny layer, and, 
secondly, that it is composed of fungi. As regards the 
fungus-layer itself, itis seen, pretty distinctly, to be constituted 
of two layers, of which, the inferior and larger in circum- 
ference, is composed of filaments, and the upper smaller one 
mostly of spores; moreover, that its vertical thickness is 
greatest in the neighbourhood of the hair follicle, where the 
spores grow most vigorously, and least at the periphery, 
where only isolated looped filaments are seen penetrating the 
superimposed epidermis. 

This disposition of the two kinds of fungus-formation may 
be demonstrated with greater certainty in another way. 

The epidermis is macerated from 24 to 48 hours in water, at 


GUDDEN, ON CUTANEOUS DISEASES. 187 


the common temperature. By this means the fungi are 
softened, and the felt-like stratum formed by it is loosened 
from the subjacent epidermis. It is to be carefully raised with 
a curved cataract-needle, so that its connexion is not broken, 
and placed under the microscope. It is true, spores alone 
are never seen, although it is now more evident than before 
that they lie principally on the surface ; and if the epidermis 
upon which, after the removal of the little fungus-stratum, 
a slight cloudiness remains, be then brought under the micro- 
scope, it will be found that this cloudiness depends solely and 
entirely upon the presence of fungoid filaments. 

The filaments are about 1-600” in diameter, roundish, ser- 
pentine, occasionally knotted, much branched, and interlaced. 
They are transparent under a power of 300, either not at all 
or but faintly yellowish, and having tolerably defined outlines. 
The older they are, the smaller is their diameter, and the 
fainter their contours. 

The spores are produced at the end of a filament, occasion- 
ally also at the side, and form racemes about 1-50’” in their 
longer diameter, which are usually so dense that it is only at 
the border that the individual cells can be distinguished. In 
a few cases where these racemes consist of only a small num- 
ber of spores, the author noticed that each spore was placed 
upon a slender peduncle of the much-divided filament. 

The spores are round, with tolerably defined outlines, and 
have a diameter of about 1-500’. In most of them, a more 
highly refractive corpuscle is perceptible, the size of which 
varies still more than in the spores of the Porrigo-fungus, 
sometimes being scarcely visible, at others nearly filling the 
whole cell; occasionally it does not exist at all, and, in many 
cases, is double. 

The fungus-stratum is covered on its surface by a thin layer 
of connected epidermis-cells; and among the fungoid fila- 
ments and cells themselves are found fragments of cuticle, 
together with a molecular detritus. 

It was observed above, that almost every patch was _per- 
forated in the centre by a hair, and that the spores were accu- 
mulated, especially in the hair-sheath. If the hair follicles in 
question, which may be easily removed from the epidermis 
underneath by means of a needle, be examined, the spores 
will be found extending deeply into them. Their number 
is occasionally so considerable that the follicles present a 
yellow colour, and if the fungus-stratum be detached by mace- 
ration in the mode above described, it will exhibit on its 
surface a conical mass of fungus enclosed in the contiguous 
epidermic layer. The author was unable to observe any 


188 GUDDEN, ON CUTANEOUS DISEASES. 


alteration in the hairs themselves, unless occasionally that they 
were a little thinned. 

In the further progress of the growth, the spots enlarge and 
begin to form a scurf on the surface, owing to the breaking 
through of the epidermic layer of fungus. The whitish scales 
under the microscope are seen to consist of epidermis-cells 
and dried filaments of the fungus. The spots approach each 
other, coalesce, form large or small islands, and, as has been 
said before, may extend over the whole trunk. When the 
fungi die, the yellow colour of the spots is removed by their 
scaling off, and there remains for a longer time a smooth spot 
containing rather less pigment than the surrounding epidermis. 

Pityriasis versicolor is contagious ; but for the success of ex- 
periments in inoculation with it, the cuticle should not be 
removed. 

The fungus enters from without, and invades localities 
where the necessary conditions for its development are 
present. It occurs in otherwise perfectly healthy persons, 
and diseases can only so far have any influence, as they may 
augment or diminish the condition favourable to its develop- 
ment, whether directly or indirectly. But the fungus has its 
seat in the uppermost horny layer of the cuticle, and avoids 
the deeper, soft layer. Whence is explained, on the one hand, 
the trifling reaction of the cutis, which is limited to a moderate 
thickening of the epidermis, and the little variety in the 
external aspect of the disease ; and, on the other, the immu- 
nity of childhood. 

Pityriasis versicolor, contrary to Porrigo, in which the 
fungus finds its nutriment in the soft layers of the epidermis, 
and is consequently especially incident to childhood, is a disease 
of adults. 

Dr. Gudden’s experiments in the cure of this affection, 
based upon the above view of its nature, do not seem to have 
been wholly satisfactory. The best results appear to have 
ensued upon the use of vesicants; but relapses seem to have 
almost invariably taken place after a time, in consequence, as 
the author believes, of the impossibility of removing the hair 
follicles to the bottom. 

From the figures added by Dr. Gudden, the fungus would 
appear to be referrible to the genus Mucor. 


On the Propagation of the Oscitrarte. By Dr. Hermann 
Irzigsoun. From the ‘ Botanisch. Zeitung,’ Dec. 16, 1853. 


Tue definite form of the Oscillarie, and the processes attend- 
ing their growth, as regards outward appearances, are well 


ON THE PROPAGATION OF THE OSCILLLARIA. 189 


known: their tenia-like, jointed structure; their contents 
composed of phycochrom ; their motility; the frequently fringed 
points of the filaments ; the continual subdivision into two of 
their joints; their rapid growth; their spreading, &c. Pre- 
mising that all this is known, I shall consider this definite 
form as the starting-point of their developmental processes, and 
proceed to indicate the relations of the other forms to it. 

I shall select as an example the Oscillaria tenuis, Ktz., as 
being that most abundantly met with, and affording subjects 
of observation under all sorts of pseudo-forms (Leptothriz, 
Phormidum, Symploca, &c.). 

As they become older, the filaments of O. tenuis, at first 
bluish-green, assume a more yellow-green colour, their contents 
acquiring pretty nearly the hue of those of the UWlotriche. 
The filaments break up into perfectly-distinct joints, which, at 
first urceolate, soon become spherical. The minute yellowish- 
green gonidia thus arising, gradually increase in size, become 
motile, and present in all respects the aspect of Chlamydomonas. 
They move by means of delicate cilia, and present in the in- 
terior, usually in the centre, a clearer green spot, a sort of 
vacuole, as I believe, which, if I do not err, has been taken by 
others for an amylaceous granule, The contents of the gonidia 
are still finely granular, and of a yellowish-green colour. 

These minute Chlamydomonades (as I shall term them, 
since no one has pointed out any morphological distinction) 
gradually enlarge; a red eye-point becomes visible in them, 
and, presenting a thousand intermediate forms, they grow into 
perfect Euglene. ‘The minute vacuole visible in them from 
the first, is, in all cases, still recognisable as a larger, clearer 
space in the mature Huglena, when the latter is extended. 
The finely-granular contents have become coarsely granular, 
the eye-point {perhaps the first indication of a reflecting 
spherule, having no further organization, for the purpose of 
conducting the luminous rays, without the intervention of any 
other medium than the fluid of the body of the Euglena to the 
perception of the individual; thence, also, the red colour, 
complementary to green; the eye-point in Euglena sanguinea, 
on the other hand, is green!| has become larger, and of a 
deeper colour, the filaments much elongated, and the move- 
ments more suitable to the now extended shape of the body. 

The uniform life of the Euglena, prolonged only by endos- 
mosis, terminates, as regards the individual, after repeated 
division, in the quiescent or “ protococcus-condition,” as it is 
termed, with which we are already acquainted from the ob- 
servations of numerous zoologists and botanists (wide, among 
others, Cohn, on Stephanosphera). In this condition the 


190 ON THE PROPAGATION OF THE OSCILLARIA. 


Euglena constitutes a large motionless spore, or protococcus- 
like globule, in which the eye-point gradually disappears ; the 
gelatinous envelope surrounding, at a short distance, a large 
number of green gonidia, which had constituted the granular 
substance of the mobile Euglena. 

After this prolonged quiescent condition, the common Euglena- 
envelope ultimately dissolves, and the gonidia escape, either 
singly, or still connected into aggregate masses, in the form of 
motile corpuscles (the microgonidia of authors). Ifa number 
of these remain conjoined, and move about with a rowing 
kind of movement, their locomotion being governed by a com- 
mon spontaneity, they represent a volvox-like colony, which, 
perhaps, may even have been described as Volvox by authors. 

The microgonidia of the Euglena, like those of all the alge 
hitherto examined by me, are the motile parent-cells of extra- 
ordinarily-minute spiral filaments. They are, at first, green, 
gradually becoming pellucid, exactly like the spermatospheres 
of Spirogyra, presenting a monadiform aspect. A peculiar 
appearance arises when, in one of these aggregations of miero- 
gonidia, many remain green, whilst the others have already 
become clear as water, the mass then presenting, in fact, 
the aspect of being composed of two kinds of animalcules. 
Such or similar conditions would represent several species of 
the supposed genus Uvella (atomus, glaucoma, bodo, &c.) 

Each ultimately colourless microgonidium, then, by the 
dissolution ef its minute gelatinous. envelope, discharges a 
small motile-spiral filament. In these, we have not the large 
spiral filaments of the Chare, Equisetacee, and Ferns. A\I- 
though, in Selaginella, these filaments are excessively minute, 
and visible only to the closest scrutiny (wide Hofmeister’s fig. 
in his ‘Comparative Researches,’ Tab. xxvi., fig. 3), still in 
Oscillaria tenuis they are, perhaps, yet more delicate. This 
investigation is, of course, one of the most difficult nature, and 
demands the most acute vision. 

These spiral filaments in the Oscillari@ do not appear to be 
destined for the purposes of impregnation, for they gradually 
increase in length and thickness, soon exhibiting innumerable 
spiral turns, and between them in the latter condition, and the 
finest spermatic filaments, a thousand different transitionary 
forms are met with. From the spiri//a-like condition, they 
pass, by an increase in length and a continual spiral move- 
ment, into a spirulina-like form. Finally, when their motile 
faculty has become weakened, they affix themselves by one 
extremity to any near, larger object (for instance, Conferva- 
filaments, &c.), whilst the other extremity continues to move 
about with a creeping motion,—the peculiar Oscillarian move- 


ON THE PROPAGATION OF THE OSCILLARLZ. 191 


ment,—in performing which a young filament frequently re- 
turns to the spiral. The last-described condition constitutes 
the Leptothrix of authors. The filaments now gradually be- 
come thicker, and though, at first, of the lightest emerald green, 
they gradually assume a deeper and deeper tint. The first 
indications of articulation are perceptible in them, until at last 
a young Oscillatoria is again perfected. 

The extremities of the young Oscillaria, as is well known, are 
fringed with hairs: this may be an indication of the existence 
of cilia, previously invisible, on the head-end of the filament, 
which end has now become the point of the Oscillaria. But 
in young plants it is not merely one or a few apical cells that 
are so fringed, for I have, in filaments thus furnished, not un- 
frequently noticed them fringed for the length of, perhaps, 30- 
50 joints. This circumstance recals to mind the long-ciliated 
spermatozoa of the Ferns and L£quisete. This investigation 
will also afford ground for many important conclusions with 
respect to the motion of the Oscillarie. 

I shall return to many peculiarities of the Euglena in an- 
other place, in speaking of other Nostochinez, and will here 
merely state that I first remarked their plant-like connexion 
in the Rivularie, in the gelatinous substance of which, when 
the Rivularia was mature, | always met with these bodies. 

Much time and continued study, together with a fortunate 
conjunction of circumstances and ingenious combinations, will 
be requisite to follow the filaments here described by me 
through the labyrinth of forms of alge, with their heterogeneous 
generations, if it be wished to apply this idea throughout that 
class of plants. 


( 192 ) 


RE VIE Ws. 


A Frora AND Fauna wituin Livine Antmats. By JosepH Leipy, M.D. 
Smithsonian Contributions to Knowledge. 


Tuart there are animals which inhabit the bodies of other 
animals as their natural locality has long been known. Many 
of these are so obvious as to be popularly recognized ‘under 
the name of “ Worms.” It is, however, only since the ex- 
tensive employment of the microscope in aiding vision, that 
any large addition has been made to those generally known. 
Not only is it found that each species of animal has its pecu- 
liar parasitic animal and plant, but every species of animal 
appears to have a Flora and a Fauna of its own. Formerly a 
country was necessary to supply the materials of a Fauna or 
Flora, but with the microscope in hand the stomach of an 
insect affords abundance of peculiar species of animals and 
plants for such a purpose, Dr. Leidy’s work is not an account 
of all the species of plants found in living animals, but an 
account of certain new genera and species of plants discovered 
by himself in the stomach and intestines of a few species of 
insects. In an introduction, Dr. Leidy refers to the plants 
and animals of the human body. ‘These are treated of at 
length in the works of Dujardin,* Diesing,+ and Robin.t 

The plants described by Dr, Leidy are as follows :— 

Genus, Enterobryus, Leidy. Thallus attached, consisting of a 
single very long tubular cell, filled with granules and globules, 
producing at its free extremity one, usually two, rarely three 
shorter tubular cells, and growing at the other end from a 
relatively short, cylindroid, amorphous, coriaceous pedicle, 
commencing with a discoidal surface of attachment. 

E. elegans is found growing from the basement-membrane 
of the mucous membrane of the small and large intestine of 
Julus marginatus, Say; and primary part of the exterior of 
Ascaris infecta, Streptostomum agile, and Thelastomum at- 
tenuatum, entozoa infesting the cavities of the viscera of the 
same animal. 

E. spiralis is found attached to the mucous membrane of 
the small intestine of Julus pusillus. 


* Histoire Naturelle des Helminthes. Paris, 1845. 

+ Systema Helminthian Vindoboniw. 1850. 

{ Histoire Naturelle des Végétaux Parasites qui croissent sur l’Homme 
et sur les Animaux Vivants. Paris, 1853. 


FLORA AND FAUNA OF LIVING ANIMALS. 193 


E. attenuatus grows from the mucous membrane of the 
ventriculus of the Passalus cornutus. 

Dr. Leidy observes that these entophyta are found in the 
herbivorous Myriapoda and Coleoptera, and in no instance has 
he been able to detect them in species which are carnivorous. 

Genus Eccrina, Leidy. Thallus attached, consisting of a 
very long tubular cell, filled with granules and globules, pro- 
ducing at its free extremity a succession of numerous globular 
or oblong cells, and growing at the other end from a relatively 
short, cylindroid, amorphous, coriaceous pedicle, commencing 
with a discoidal surface of attachment. 

£. longa was found growing in profusion from the mucous 
membrane of the posterior part of the intestinal canal of 
Polydesmus virginiensis. 

E. moniliformis was found growing upon the mucous mem- 
brane of the intestinal canal of Polydesmus granulatus. 

Genus Arthromitus, Leidy. Thallus attached, by means of 
one or more granules, simple, cylindrical, very long, fila- 
mentous, articulate without ramuli. Articuli indistinct, with 
amorphous contents finally converted into solitary oval 
sporules. 

A. cristatus grows from the mucous membrane of the ven- 
triculus and large intestine of Julus marginatus, and also upon 
Enterobryus elegans, Ascaris infecta, Streptostomum agile, and 
Thelastomum attenuatum ; from the mucous membrane and its 
appendages of the ventriculus of Passalus cornutus, and Poly- 
desmus virginiensis, and upon Eccrina longa. 

Genus Cladophytum, Leidy. Thallus attached by means of 
one or more granules ; filamentous simple, with minute lateral 
ramuli, or branched inarticulate amorphous in structure. 

C. cornutum was found in the same positions as Arthromitus. 
It is very minute. The filaments measured from the 1-700th 
to the 1-100th of an inch in length, by the 1-80000th to 
1-25000th of an inch in diameter. 

Genus Corynocladus, Leidy. Thallus attached by means of 
one or more granules; filamentous very compound ; branches 
thicker than the trunk, without ramuli; inarticulate amor- 
phous in structure. 

C. radiatus was observed growing from the mucous mem- 
brane and its appendages of .the ventriculus of Passulas 
cornutus. 

In addition to the above genera and species, Dr. Leidy 
describes some parasitic phytoid bodies, whose structure he 
could not well make out. 

Associated with this Flora, Dr. Leidy found the following 
Fauna :— 

VOL, II. P 


194 FLORA AND! FAUNA OF LIVING ANIMALS. 


In Julus marginatus were found— 

Gregarina Juli marginati, Ascaris infecta, Streptostomum 
agile, Thelastomum attenuatum, Nyctotherus velox, Bodo Julidis, 
a species of Vibrio. 

In Passalus cornutus were found— 

Gregarina Passali cornuti, Hystrignathus. rigidus. 

In Blatta orientalis, the common cock-roach, were found— 

A species of Vibrio, a species of Bodo, Nyctotherus ovalis, 
a species of Gregarina, Streptostoreum gracile, Thelastomum 
appendiculatum. Of these, Ascaris infecta, and the genera 
Hystrignathus, Streptostomum, and Thelastomum, are new. 

Dr. Leidy has also a chapter on pseudo- entoph yta. He is 
inclined to regard many of the free-floating vibrio-like, not 
spontaneously Viloviae filaments, as plants. The following 
caution may be useful :-— 

“Jn the study of the vegetable parasites of animals, particularly those 
of the intestinal canals, it is necessary to be careful not to confound tie 
tissues of certain well-knéwn cryptogamic plants, which may serve as food, 
or adhere to the ordinary food of such animals, with true entophyta. 
Thus fragments of fungi, confervee, lichens, and the spores of these, used as 
food, or adhering as foreign matter to food of an ordinary kind, are liable 
within the intestines to be mistaken for parasites. 

‘‘In mid-winter I found beneath an old fence-rail an individual of 
Acheta nigra, or large black cricket, within the proventriculus of which 
were large quantities of what I supposed at the time to be a free, floating 
entophyte, resembling in general appearance the ordinary yeast fungus 
Torula, but which I now suspect to be an ergot upon which the animal 
had fed. 'The*plant consisted of oblong or oval vesicular bodies, appa- 
rently thickened at the poles, and filled with a colourless liquid ; but this 
appearance, more probably, arose from the cells being distended with a 
single large, transparent, colourless, amorphous globule, which pressed a 
small existing amount of protoplasma to each end of the cavity. ‘The cells 
were single, or in rows to eighteen in number. Frequently a single cell of 
comparatively large size had an attached pair of cells, or rows of cells, at 
one or both ends. Occasionally they are met with containing one or two 
small round hyaline amorphous nuclei. The isolated cellules measured 
from the 1-2500th to the 1-1666th of an inch in length, by the 1-8000th 
to the 1-6000th of an inch in breadth. The rows measured up to the 
1-300th of an inch in length.” 

He adds that it is not improbable that an occasional new 
species of cryptogamic plant might be discovered in the ex- 
amination of the contents of the intestine of such animals as 
the earth-worm, herbivorous Myriapoda herbivorous insects, 
Chelonians and Batrachians. Some such bodies he describes, 
and regards it as probable that they may produce some of the 
cryptogamia which appear externally on animals, as Botrytis, 
&e. There can be little doubt of the importance of this field 
of observation, and in some of these, at present obscure 
organisms, may yet be discovered the sources or indications of 
states of disease to which the animal body is subject. 


TRANSACTIONS OF PATHOLOGICAL SOCIETY. 195 


The work is illustrated with ten beautiful plates illustrating 
the details of the structure of the new plants and animals 


described by Dr. Leidy. 


TRANSACTIONS OF THE PaTHotosicaL Society or Lonpoy. Vol. IV. (for 

the Session 1852-53). 
Tus volume contains the results of the Society’s proceedings 
during the Session of 1852-53, and presents a great amount 
of matter interesting to the pathological histologist. Among 
other papers of considerable value in that point of view, 
we would indicate more especially an account by Dr. Bris- 
towe, of the appearances exhibited in a case of “ Encepha- 
loid cancer of the dura mater, and of the periosteum of the 
ribs,” &c.; as also a paper by the same observeron the sup- 
posed coexistence in the lungs of cancer and miliary tubercle (?). 
But which latter productions are pronounced by Drs. Jenner 
and Bristowe to be likewise of a cancerous nature, and not 
tuberculous. 

Dr. Bristowe also records the occurrence of “ hematoid 
crystals in a hydatid cyst,” p. 166—a fact of considerable 
interest. They are thus described: “In every part of the 
cyst were numerous free vermilion spots, the largest of which 
were about a line in diameter, and which clearly consisted, 
to the naked eye, of rhomboidal crystalline plates. Micro- 
scopic examination showed that all the vermilion points were 
really colourless plates of cholesterin, the surfaces of which 
were thickly studded with ruby-coloured, more or less regu- 
larly rhomboidal crystals, having all the characters of the 
bodies usually described as hematoid crystals. The largest 
of them were about the thousandth of an inch in the long 
diameter. The remains of Echinococci were everywhere 
visible.” 

We notice also a valuable paper, by Mr. Jabez Hogg, on 
‘* Enchondroma of the Testis,” and in other situations, illus- 
trated with excellent figures. We do not, however, perceive 
how the occurrence of true bone in an enchondromatous mass 
from the mamma of a bitch, or its characters, favours the view 
entertained by Professors Todd and Bowman, viz.: “that the 
lacune are developed from the nuclei of the cartilage cell.” 
The latter statement, moreover, being one of whose truth there 
is, at any rate, very considerable reason to doubt. 

Dr. Handfield Jones describes the intimate nature of the 
condition of the gastric mucous membrane, termed ‘ mam- 
mellation.” The small whitish eminences which give the 

-membrane the peculiar aspect thus denominated, were best 


p 2 


196 TRANSACTIONS OF PATHOLOGICAL SOCIETY. 


seen in vertical sections as whitish grains or masses in the 
submucous tissue. These masses consisted of tortuous tubes 
crowded and _ packed together, and filled with an epithelium 
composed of smaller-sized cell-particles and free nuclei, toge- 
ther with abundant amorphous granular matter and much oil. 
In the intervals of the masses there were no tubes, and the or- 
dinary parallel arrangement was entirely lost. Dr. H. Jones 
thinks that the tubes, thus filled, bear some real resemblance 
to the granulations of a diseased kidney ; and like them, result 
from the decay of the surrounding tissue and the distension of 
the canals by epithelium. He concludes, therefore, that there 
is some reason to believe that the glandular secreting structure 
of the stomach is liable to degenerative disease of the same 
kind as those which affect the kidney or liver. One of these 
is a fatty degeneration, the other a change more analogous to 
granular renal disease. 

That there is some truth in these views is highly probable ; 
but at the same time we do not conceive that the condition of 
the mucous membrane above described is necessarily, in all 
cases, one of degeneration, or even of disease, consisting pro- 
bably, in many instances, simply in an infraction of the tubes 
of the gastric mucous membrane, with epithelium, either 
temporary, or more or less permanent. 

Mr. John Marshall describes the appearances observed on 
the examination of a case of lobular hepatitis.. And Dr, Lionel 
Beale gives an account, which we regret is so short, of the 
contents of a cyst in the kidney, which would seem to throw 
additional light upon the vexed question of these cysts, to 
which we adverted more at length in our notice of the previous 
volume of the Pathological Society’s Transactions. The large 
cyst in Dr. Beale’s case appears to have been lined with 
epithelium, and besides this, he states “ that the tubes formed 
dilatations in the meshes of the matrix.” Dr. Hare records a 
similar case, but unfortunately seems to have omitted any 
microscopic examination of the lining of the cyst. Dr. 
Handfield Jones notices the occurrence of a ‘“ peculiar form of 
uric acid crystals,” presenting the aspect of “spherical or 
polygonal grains, $53 inch in diameter, and showing a con- 
centric and radiated structure. On solution in liquor potasse 
they left behind some granulous film, and some transparent 
capsules of homogeneous membrane.” What could be the 
chemical relations of this membrane ? 

There is also an interesting communication from Dr. Bris- 
towe on “muscular or fibrous tumours of the uterus,” in which 
he shows that these tumours, at all events in some cases, are 
composed wholly of muscular fibre-cells, similar to those of 


PAGET, ON SURGICAL PATHOLOGY. 197 


the uterus itself, and are not simply fibrous tumours, contain- 
ing a greater or less quantity of muscular fibre mixed up with 
them. 

Associated with so many valuable contributions to micro- 
scopic pathology, we regret to find a paper, which, as regards 
that branch of science, at any rate, is by no means calculated 
to advance knowledge, or to add credit to the transactions of 
the Pathological Society. We refer to a paper by Dr. Black 
of Chesterfield, descriptive of a case of hydatids expectorated 
from the left lung, subsequently to the occurrence of typhoid 
fever, Kc. It is a subject for regret to find an observer, so 
zealous and acute as Dr. Black appears to be, so grievously 
misled by the procrustean force of preconceived notions, as to 
describe such objects as those represented in PI. II. fig. A., 
as portions of nerve tube and lymphatic vessels contained in 
the sputa. In no possible condition could either of those 
tissues present appearances like those figured by Dr. Black. 
The objects most probably represent portions of vegetable or 
animal hairs, But a more serious matter in Dr. Black’s paper 
is in what he says respecting the hydatids expectorated from the 
lungs (p. 52). That these were true hydatids, or echinococcus- 
cysts, is sufficiently obvious from their appearance under the 
naked eye; but when Dr. Black proceeds to describe their 
intimate structure as viewed under the microscope, it is 
difficult to decide, whether we should most admire his in- 
genuity in building up a theory on the most baseless suppo- 
sitions, or his apparently complete ignorance as to the true 
nature of hydatid cysts. All that need be remarked concern- 
ing this portion of the paper is, that it is absolute nonsense ; 
and we cannot but wonder and regret that some friend in the 
Pathological Society, should not have suggested as much to 
the author before the publication of the paper. If we were 
called upon to select a typical instance of theorizing run mad, 
it would be the description here given of the mode in which 
the walls of hydatid cysts come to be laminated (p. 57). It 
is to be hoped that Dr. Black will be more careful in drawing 
conclusions on future occasions. 


LEcTURES ON SuRGIcAL PatruoLtocy. By James Pacer, F.R.S. London. 
Longman. 


We cannot discuss in our pages the general principles of 
Surgical Pathology, but we are anxious to call attention to 
Mr. Paget's book, because it recognises the aid which micro- 
scopic research is calculated to confer on the principles of 
Pathology, whether involving the art of the physician or the 


198 PAGET, ON SURGICAL PATHOLOGY. 


surgeon, We are sorry to know that there are still some 
persons practising the medical profession who doubt the 
benefit to be derived from the use of the microscope in the 
practice of Medicine and Surgery. Such persons suppose 
that because the diseases they treat get well without the use of 
the microscope, that therefore the microscope is of no use in 
practice. They forget that this argument can be employed 
by every pretender to medical skill, and that the results: of 
treatment are to be looked for in the improved: state of the 
public health, in the ability to cure disease, and increased 
intelligence of the members of the medical profession. ‘The 
discoveries made by the microscope, and their influence on 
the practice of Medicine, have perhaps been more evident in 
exposing the absurdity of an empirical practice than in sug- 
gesting new methods of rational treatment. But such works as 
the present are the best answer that can be given to the igno- 
rant assertion that the microscope is of no value in the prac- 
tice of the healing art. It is all very well for the blind to 
say that eyes are of no use, but those who see are best able 
to appreciate their value. 

Although at first sight it might be thought that Surgery is 
more independent of the use of the microscope than other 
departments of medical practice, a little reflection will show 
that its application to the study of the nature of inflammation, 
the healing of wounds, the repair of fractures, the results of 
inflammation; and the nature and growth of simple and 
malignant tumours, is of the utmost importance. The mission 
of the surgeon is not to operate, but to avoid operations ; and 
he who knows most minutely the nature of disease will be 
most likely to attain this object of his art. That Mr. Paget 
has been sensible of this we have abundant proof throughout 
these very able lectures ; and we can conscientiously recom- 
mend them as examples of the manner in which researches in 
Pathology should be conducted. There are many subjects 
ireated of in this work that we should liked to have discussed 
in our pages, but our limits will not permit us on the present 
occasion ; and we are anxious not to allow another Number of 
our Journal to be published without calling the attention of 
our surgical readers to its pages. 

The work consists of two volumes, illustrated with a large 
number of woodcuts, which refer more especially to the 
subjects demanding microscopical research. In the first 
volume the subjects of hypertrophy, atrophy, repair, inflam- 
mation, mortification, and specific diseases, are taken up. 
The second volume is entirely devoted to the various kinds of 
tumours. In this volume, of the subjects discussed, the one 


GAZZETTA MEDICA ITALIANA. 199 


to which most practical interest is attached is evidently 
that of the distinctions between malignant and non-malignant 
tumours. . Mr. Paget thinks the distinction can be made out 
by microscopic characters. With regard to cancer structures, 
he says they may be generally described as formed of “nu- 
cleated cells, or of such corpuscles as are rudimental of or 
degenerate from the nucleated cell. Herein, and in the fact 
that the corpuscles are neither imbedded in formed inter- 
cellular substance, nor orderly arranged, lies one of the cha- 
racters by which caneers are distinguished from other tumours 
and from all natural parts.” A connected view, however, of 
the origin and development of malignant tumours is still a 
Orn ey and much more remains to be done before a 
satisfactory histological account can be given of these truly 
terrible conditions of cell-formation in the animal body. 


Gazzetra Meprica Irarrana, Ser. II., No. 43, for October 25, 
1853. 


Tuis Journal contains a paper by Professor Pacini, on the 
‘Structure of the Retina; communicated chiefly for the pur- 
pose of indicating certain points, in which the statements on 
that subject made by him (Sudla tessitura della retina), and 
published in 1845 in the ‘ Nuoyi Annali di Scienze Naturali 
di Bologna,’ have anticipated the more recent observations of 
Miller and Kélliker. The points in which the observations 
of the later authors correspond with those of the Florentine 
Professor, include the subdivision of the retina into five dis- 
tinct layers, which Professor Pacini enumerates from within 
to without, commencing with the limitary membrane (mem- 
brana limitante) the discovery of which appears to be due to 
him, as is also the credit of haying been the first to indicate 
the resemblance between the nucleated corpuscles of the retina 
and the nerve-cells. In fact, the main additional fact of much 
importance made known by Miller and Kolliker, is the ex- 
istence of fibres prolonged from the ‘rods and cones’ of the 
bacillar layer, and probably communicating with the fibres of 
the optic nerve. But this discovery is one of so much im- 
portance, as alone to mark an era in the histological history 
of the retina, in which, as regards other particulars, Professor 
Pacini has played a much more important part than appears 
hitherto to have been conceded to him, 


( 200 ) 


NOTES AND CORRESPONDENCE. 


Composition of the Boghead Coal.—In compliance with the 
request of the President of the Microscopical Society, 1 beg to 
send you a copy of the results of my examination of the Bog- 
head mineral, called Boghead coal (brown variety). 

It is of a dingy drab colour, very compact and difficult to 
pulverize; it has a slaty somewhat conchoidal fracture, and 
is easily scratched by the nail, a light-brown streak being left. 
Burnt in a crucrble it evolves an abundance of exceedingly 
luminous gas, and the (coke?) left retains exactly the form of 
the mass Salmnitied to distillation, and is of whitish colour. 
This so-called coke will not burn, but when ignited in con- 
tact with the air it leaves a white ash. Reduced to very fine 
powder, and treated with coal-naphtha (the same as is used in 
the manufacture of marine glue), the mineral yields a brown 
solution, which evaporated leaves a resinoid mass, and the 
residue left after treatment with the above-mentioned men- 
struum may be partially dissolved by treatment with boiling 
concentrated sulphuric acid, 

The specific gravity of the samples examined varies from 
LL tot lle. 


Its constituents are as follows :— 


Volatile matter - - - 67°28 
Carbon - - - - 9°43 
Ashes - - - - Zeno 
Sulphur in coal - - 0:88 0°88 

Ditto in coke - = 0°86 

Ditto in volatile matter - 0°02 
100°88 

Composition of the ashes :— 

Silica - - = - - 53°6 
Peroxide of iron - - - 40 
Alumina - - - - 39°2 
Carbonate of lime -—- - - 32 
100°0 


A. Normanpy, 67, Judd Street, Brunswick Square. 


the Boghead Coal.—l| have just received the Journal, and I 
find in it a statement, copied from the ‘Commonwealth,’ 


MEMORANDa. 201 


which I must correct. It is there stated, that I said at the 
Royal Society of Edinburgh that I regarded the Torbane 
mineral as differing from bituminous shale, because 1 could 
not extract bitumen from it by any solvent. 

Now what I really stated was this, “ that bituminous coal 
and bituminous shale were wrong names, inasmuch as no true 
bitumen existed in either, or could be extracted by those 
solvents in which true bitumen is soluble. I added that the 
combustible matter in the mineral was, like that of coal, not 
true bitumen, and that I could find no chemical difference 
between it and the combustible part of ordinary coal. Some 
persons regarded the mineral as earthy matter which had 
become impregnaied with bitumen ; but this was not the case, 
if by bitumen be meant the substance, allied to asphalt, com- 
monly so called. My argument was that since I could find no 
chemical distinction between the combustible matter in this 
mineral and that in coal, the mineral was, chemically con- 
sidered, a coal. As to structure, that is often wanting in 
portions of coal, and besides, Dr. Traill had just said that no 
true distinction could be founded on the absence of structure.” 

By the report in the Journal I am made not only to say 
nearly the reverse of what I did, say, since I maintained the 
identity of the combustible or bituminous matter in coals, 
shales, and the mineral, but Iam made to talk downright 
nonsense, as if I maintained that solvents could extract bitu- 
men from shale, which I said they could not. 

Allow me also to point out that the Reviewer of Fresenius 
on Mycology has made a mistake in translating Unscheinbarkeit 
‘‘unsightliness.” It means not precisely invisibility, but the 
want of obvious perceptibility ; and F’. means to say that it is so 
difficult to see the structure and organs of fungi that people 
are thereby deterred from the study. The phenomena are too 
obscure, too little apparent, to attract the many. This is his 
true meaning, for which no single English word will suffice.— 
WILLIAM Grecory, Edinburgh. 


A defence of the proposed new genus “ Actinophenia”—Shadbolt. 
—In a paper by Mr. Roper on the “ Diatomacee of the 
Thames,” read before the Microscopical Society in January 
of the present year, that gentleman alludes to a species pre- 
viously described by me (under the name of Actinophenia 
splendens, occurring in the Port Natal gathering of Diatomacea, 
and also found abundantly in the Guano from Callao), as 
being probably somewhat similar to one found by him amongst 
the Thames deposit, but he refers bis species to the genus Acti- 
nocyclus of Ehrenberg, under the specific name sedenarius. As 


202 MEMORANDA. 


it is evident from the remarks which accompany his deserip- 
tion that he has mistaken my reasons for not classing the 
species in question as he has done, it is probable that others 
may have not comprehended them ; and I think it right, con- 
sequently, to endeavour to show, that my object was not a 
needless multiplication of genera, more especially as I per- 
ceive from Mr. Roper’s drawing that our attention is directed 
to one identical plant. 

I am aware that it may look like presumption in me to 
enter the lists against so great an authority as the learned Pro- 
fessor quoted ; but, in the first place, 1 am by no means satis- 
fied that I really do differ from Ehrenberg, and even if | 
do, it is by no means surprising that a minute flaw should be 
perceptible to the Lilliputian that was overlooked by the 
giant. 

In all the Actinocycli proper, the number of segments 
formed by the septa is always even, and every alternate segment 
occupies a position ina different plane from that in immediate 
contiguity to itself. This is so marked a character, that it 
cannot fail to be observed when once pointed out. The front 
view presents an undulating outline, and the two valves are so 
placed that the alternate segments in each fit into one another, 
the septa also coinciding; but in the genus which I have 
called “* Actinophenia,” the case is in every way different even 
according to Mr. Roper’s own description (the correctness of 
which I quiteadmit), for here, as in the genus “ Arachnoidiscus,” 
the segments are ail in one plane, and the septa all in another, 
being placed internally. Moreover, the front view of the two 
valves presents a sort of double scallop in outline; and to 
crown the whole, the septa of the inferior valye are not placed 
opposite to those in the superior one, but intermediately. 
Surely all these points are sufficient to establish a generic 
difference ; but if not, there is another to which I would direct 
the attention of microscopists, viz., the structure of the frustule. 
In the genera Actinocyclus, Coscinodiscus, Triceratium, Acti- 
nophenia, and Arachnoidiscus, | have most distinctly and un- 
mistakably detected the presence externally of a sort of mem- 
brane not unlike cellulose, having very minute reticulations, 
puncta, or cells (according to the fancy of the observer); for 
they are so minute that it is impossible to pronounce with any 
degree of certainty even when viewed under the very highest 
powers of our finest instruments ; and this external membrane 
is not brittle like the siliceous part, but tough and capable of 
being folded and unfolded without its necessarily breaking ; and 
this in the genus “ Arachnoidiscus”’ 1 have actually accom- 
plished, and recorded the fact'in a paper published in the 


MEMORANDA. 203 


‘Microscopical Society’s Transactions.’ This external mem- 
brane is in all the genera I have quoted, supported by a siliceous 
framework ; but if we examine those of Actinocycli and Actino- 
phenia, how different they appear, the one having a strong 
siliceous network between the septa, and the other being 
quite destitute of such an appendage. It seems that Mr. 
Roper has noticed the membrane to which I have alluded, but 
has not probably been aware of its character ; and has evidently 
fallen into the error of supposing that I had relied upon that 
as a characteristic difference, because the markings are exceed- 
ingly patent in Actinophwnia from the absence of the net-like 
reticulations in the siliceous part, and somewhat obscured by 
their presence in the Actinocycli, and the other genera pre- 
viously mentioned. 

One other objection I have to make is to the specific desig- 
nation sedenarius, founded upon one of the most inconstant 
characters that can be employed, viz., number—and it un- 
fortunately happens in the present case, that the variation in 
the number of septa is so frequent, that seventeen to twenty 
might quite as well have been selected as the number employed. 
I am aware that Mr. Roper merely took up what he conceived 
to be Ehrenberg’s view, and that the specific designation was 
not of his selecting ; but if he will examine a slide of Callao 
Guano, he will, I am sure, be satisfied as to the inconstancy 
in the number of septa. 

Under all these circumstances, I submit that I have adduced 
sufficient evidence to establish the claim of the “ Actinophenia” 
to a separate generic distinction, whether | have chosen a 
proper designation or not, | must leave to others to decide — 
GEORGE SHADBOLT. 


@n a Beveloping Solution for Microphotographs made by 
artificial Wight.—The developing solution, of which the tfor- 
mula is here given, appears to possess a considerable advan- 
tage over pyrogallic acid, used in the common way, in the 
production of microphotographic collodion negatives. The 
black is much more intense than that which I have been able 
to procure by the use of pyrogallic acid, and the lights fully as 
clear, if not more so, That it will keep, is also an advantage, 
though a trifling one, as it can be made extemporaneously in 
a few moments at any time. Whether it will answer as well 
for microphotographs made by daylight, and for the usual 
camera-pictures, my experience will not allow me to state ; for 
the latter I have fancied it not well adapted—but why, | do 
not know. The solution is made by dissolving 

30 grains protosulphate iron, 
10 grains tartaric acid, 


204 MEMORANDA. 


in 1 fluid ounce of water, acidulated with two drops of nitric 
acid, It is, perhaps, needless to remark that the iron-solution 
without the tartaric acid, answers very well for positives on 
the glass. The light I have used for microphotography has 
latterly been common gas, with a good Argand burner, which 
I find quite sufficient for the 4-10ths and under, The time 
required is from 5 minutes to 15 minutes. Under longer ex- 
posure the collodion begins to dry.—G. B. 


Mode of Growth of Parasitic FungiimAs all the scientific 
men of this country agree in opinion as to the mode of attack 
and growth of fungoid diseases on plants, it may seem pre- 
sumptuous, if not superfluous, to add anything to what has 
already been said upon the subject. May it not, however, be 
possible that many of these men whose names stand so high as 
to cause their opinion to be received as authority, without 
further investigation—may it not be possible that in the great 
variety and multiplicity of their pur- 
suits they may have passed over so 
rae a comparatively unimportant a subject ? 

RE } For, if they had brought the full 
SS powers of their investigations to bear 
upon it, they could not fail to have 
been convinced of what I am now 
about to advance: that fungi do not 
enter and ramify in the tissues and 
send up stems through the stomata 
of living healthy plants,* but that 
they only grow upon the surface, as 
may easily be seen, if proper care be 
observed in preparing sections for the 
microscope. I have bestowed a great 
deal of time and attention on the subject, and feel fully con- 
vinced that the mode of growth of this class of fungi is as 
represented in the annexed illustration, which, should you 
think it, with the accompanying remarks, worthy your notice, 
you will oblige by inserting in your excellent Journal for 
April.—Epwarp Tucker, Margate. 


* I wish to be understood to refer especially to the class of fungi, 
Hyphomycetes, or Mucedines, which includes Botrytis and Oidiwm. 


( 205 ) 


PROCEEDINGS OF SOCIETIES. 


Microscoricat Society. January 25th, 1854. 
George Jackson, Esq., President, in the Chair. 

Geo. Coles, Esq.; Montague Leverson, Esq.; J. H. Roberts, 
Esq.; T. W. Burr, Esq. ; Wm. Stuart, Esq.,—were balloted for, 
and duly elected Members of the Society. 

A paper was read by F. C. S. Roper, Esq., on the Diatomacez 
of the Thames (Transactions, vol. ii., p. 67). 

‘A paper was read by R. S. Boswell, Esq., entitled Remarks upon 
the Bird’s-head process found upon Cellularia plumosa, and other 
zoophytes. 

February 15.—Anniversary Meeting (Transactions, voi. ii. p. 83). 


Royau Institution. March 17th, 1854. 


On the Construction of the Compound Achromatic Microscope. 
By Cuarztes Brooke, M.A., F.R.S., Surgeon to the Westminster 
Hospital. 


Arter briefly adverting to the ordinary phenomena of reflection, 
the lecturer illustrated those of refraction by a moveable diagram, 
which readily explained the total reflection of a ray of light incident 
on the common surface of two media, at an angle greater than the 
critical angle, corresponding to which the angle of refraction is 90’. 

The aberration of reflected or refracted light at a spherical surface 
was then alluded to; and although the reflectors employed in micro- 
scopes may be rendered free from spherical aberration by giving 
them an elliptic, and those of telescopes a parabolic form, there is no 
practicable method at present known of constructing lenses otherwise 
than with spherical or plane surfaces ; and from the difficulty of ob- 
taining sufficiently perfect reflecting surfaces, and of preserving 
them when obtained, refracting microscopes are now universally 
employed. 

Chromatic dispersion was then mentioned, and the usual mode of 
producing achromatism by the combination of various kinds of glass, 
which differ in their dispersive power, which was illustrated by a 
combination of three prisms. The construction of achromatic object- 
glasses was next explained, as well as the nature of the aberration 
produced by the presence or absence of a plate of thin glass, covering 
the object, and the mode of correcting it in object-glasses of high 
power, by varying the distance of the anterior from the posterior 
combinations, as first applied in practice by Mr. A. Ross, and fully 
detailed in his article on the Microscope in the ‘ Penny Cyclopedia.’ 

The angle of aperture of object-glasses was then explained, and 
the power of those of large angular aperture in developing the struc- 
ture of certain test objects, such as the siliceous shells of Diatomacee, 
was explained to be totally distinct from the mere increase of light 
transmitted. 


206 PROCEEDINGS OF SOCIETIES. 


Mr. Brooke offered an hypothesis as to the structure of these 
objects, from which it would necessarily follow that the structure 
would be rendered visible by oblique rays alone, and the necessary 
degree of obliquity would depend upon the smallness of the elevation 
on the undulating surface of the shell. This view was then shown 
to be highly probable. A specimen of the Plewrostgma formosum 
(first found by Mr. Brooke, at Walton-on-the-Naze) was viewed 
under a 43-inch object-glass by Ross, and an achromatic eye-piece of 
high power (which was stated to be unquestionably superior to a 
deep Huyghenian eye-piece) ; when an opaque dise was interposed 
between the object and the centre of the object-glass, which cut off a 
large portion of the central rays, the diagonal rows of dots were still 
distinctly visible; but when the marginal rays were stopped out by 
a diaphragm, although a much larger quantity of light was admitted 
than in the former case, the markings were entirely lost. 

In order to render visible the more difficult objects of this class, 
glasses of large angle of aperture have been constructed ; but their 
employment is much limited, owing to the greatly-increased diffi- 
culty of correcting the aberrations of the transmitted pencil of light, 
and consequently the small amount of correction, that is, of adapta- 
tion to altered circumstances, that they admit of. From investiga- 
tions which he knew to be in progress, the lecturer expressed a hope 
that by due adjustments of the illuminating pencil, the most difficult 
objects would be rendered equally visible under object-glasses of 
moderate aperture, which are much more generally useful. 

Mr. Brooke then alluded to the preposterous angle of aperture of 
certain foreign object-glasses, viz., 172°, and explained the fallacy of 
the ordinary method of determining that angle, which consists in 
viewing through a microscope the ‘ight of a lamp placed at a few 
feet distance, and moving either the light or the microscope, so as to 
traverse the centre angular distance through which the light is visible. 
In this method, the course of the rays is contrary to what is usual, 
and oblique pencils may be brought to an imperfect focus at the 
back of the object-glass, and produce a glare of light, but which 
meet at a greater angle than the extreme rays that can enter the 
object-glass from the field of view, and which, consequently, are the 
extreme available rays. 

A very perfect instrument for measuring the angle of aperture, 
designed by Mr. Gillett, was then explained. This consists of two 
microscopes, the optical axes of which may be adjusted to coinci- 
dence. One of these is attached horizontally to the traversing arm 
of a horizontal graduated circle, and is adjusted so that the point of 
a needle, made to coincide with the axis of motion of the moveable 
arm, may be in focus and in the centre of the field of view. The other 
microscope, to which the object-glass to be examined is attached, is 
fixed and so adjusted, that the point of the same needle may be in 
focus in the centre of its field. The eye-piece of the latter is then 
removed, and a cap with a very small aperture is then substituted, 
close to which a lamp is placed. It is evident that the rays trans- 
mitted by the aperture will pursue the same course in reaching the 


PROCEEDINGS OF SOCIETIES. 207 


point of the needle, as the visual rays from that point to the eye; but 
in a contrary direction, and being transmitted through the moveable 
microscope, the eye will perceive an image of the bright spot of 
light, throughout that angular space, that represents the true aperture 
of the object-glass examined, The applications of this instrument 
in the construction of object-glasses are too numerous to be here de- 
tailed. 

The important subject of illumination was then so far considered 
as the short space of time allotted to the discourse would permit. 
It may be taken as an axiom. ‘that in the illumination of transparent 
objects, the amount of definition will depend upon the accuracy with 
which the illuminating rays converge upon the several points of an 
object ; consequently, the source of light and the field of view must 
be the conjugate foci of the illuminator ; of which an achromatic 
combination, similar to an object-glass, is the best form, and the con- 
cave mirror commonly employed is probably the worst, inasmuch as 
in a pencil of rays obliquely reflected at a spherical surface, no focal 
point exists. 

The first compound microscopes on record, as those of P. Bonnoni, 
about 1697, which were placed horizontally, and that of J. Marshall, 
in the beginning of the eighteenth century, which was vertical, were 
furnished with central condensers; but in later years the perfection 
of the illuminating apparatus has by no means kept pace with that 
of the ocular portion of the microscope, though scarcely of less im- 
portance, in attaining the utmost practicable perfection in the vision 
of microscopic objects. 

The advantages of employing an achromatic condenser were first 
pointed out by Dujardin; since which time an object-glass has been 
frequently but inconveniently employed, and more recently achro- 
matic illuminators have been constructed by most of our instrument- 
makers. Some years since Mr. Gillett was led by observation to 
appreciate the importance of controlling, not merely the quantity of 
light, which may be effected by a diaphragm placed anywhere be- 
tween the source of light and the object, but the angle of aperture 
of the illuminating pencil, which can be effected only by a diaphragm 
placed immediately behind the achromatic illuminating combination. 
An elastic diaphragm, or artificial pupil, as it might be called, was 
first proposed by Mr. Brooke, which was shown to answer very well 
in a large model, and produced a remarkable semblance of vital con- 
tractility ; but mechanical difficulties interfered with its application, 
and the revolving diaphragm in the instrument now well known as 
Gillett’s condenser was substituted.* 

When the rays of light converging on the field of view meet at a 
greater angle than that of the extreme rays that can enter the object- 
glass, the dark-ground illumination is produced, in which the objects 
are seen in strong lines of light on a dark ground: this is best suited 
to objects having a well-marked outline, such as spicula of sponges, 

* A description of this very useful apparatus has been recently pub- 


lished in the ‘ Elements of Natural Philosophy,’ by Golding Bird and 
Charles Brooke. 


208 PROCEEDINGS OF SOCIETIES. 


or the shells of the Polygastrica. This may be effected either by 
Wenham’s truncated parabolic reflector, or by a central opaque stop 
in Gillett’s condenser. 

The value of this kind of illumination in certain cases was shown 
by its effect in rendering visible the persistent cell-walls in a speci- 
men of hard vegetable tissue, a section of a plum-stone ; which could 
hardly be distinguished by the ordinary or bright-ground illumina- 
tion. A white cloud brightly illuminated by the sun has long been 
recognized as the best source of illumination ; butas this is not often 
obtainable, the light of a Jamp thrown upon a flat surface of plaster 
of Paris, or powdered carbonate of soda, has been used as a substi- 
tute. <A flat surface of white enamel, finely ground, but not polished, 
has been used with advantage by Mr. Gillett, as the surface can 
always be rendered perfectly clean by a little soap and water. By 
either of these means the glare resulting from throwing the unmodi- 
fied light of a lamp on the object is completely obviated. 

The effect of glare, or diffused light, in interfering with the vision 
of an object, was illustrated by reference to an experiment of Pro- 
fessor Faraday’s, in which a screen of gauze, partially blackened, is 
held in front of a printed placard or diagram: the diffused light 
reflected from the white gauze considerably obscures the object, which 
is scarcely interfered with by the blackened portion. 

The influence of illumination upon definition was rendered very 
evident by placing the two halves of a fly’s tongue, similarly mounted, 
under two microscopes, having precisely similar object-glasses and 
eye-pieces: the one was carefully illuminated by an achromatic 
condenser and artificial white cloud; the other by the light of a 
similar lamp reflected from a concave mirror. The difference was 
so conspicuous, that some were inclined to doubt the identity of the 
objects. 

The whole subject of the illumination of opaque objects, as well 
as that of oblique illumination, by Kingsley’s condenser, and by the 
prisms of Nachet and Amici, of which diagrams were exhibited, and 
by other means, was unavoidably omitted. Microscopes by the 
three leading makers were placed on the table, between the optical 
parts of which Mr. Brooke declined the task of drawing any invidi- 
ous distinctions ; he, however, expressed a preference for the stand 
of Mr. Ross, on account of its having a secondary stage, with rec- 
tangular adjustments, and a rotary movement, by which any illumi- 
nating apparatus may be made to revolve after its axis has been 
brought to coincide with that of the microscope. A stand of Mr. 
Ladd was also exhibited, in which the various movements are effected 
with great smoothness, and without ‘loss of time,” by means of 
wrapping chains; also, the ingenious apparatus of Mr. Highley for 
obtaining photographs of microscopic objects, of which time did not 
admit of any explanation being offered. In a curious and compli- 
cated microscope, the property of Professor Quekett, constructed 
about the middle of the last century by Benjamin Martin, might be 
noticed several points of fombreuas that have been introduced as 
recent improvements. 


DESCRIPTION OF PLATE VI. 


1.—Cocconeis placentula. 
2.—Actinocyclus sedenarius ? 
3.—Triceratium striolatum. 
4.—Campylodiscus bi-costatus. 
5.—Zygoceros Rhombus. 

6 a.—Odontidium Harrisonii ? 


6 b— 8 a front view. 

7.—Rhaphoneis gemmifera. 

8.— 5 fasciolata. 

9.— 35 pretiosa. 
10.— mt rhombus. 
11.—Zygoceros Surirella ; front view. 
12.— 7" be side view. 


13.—Front view of Actinocyclus sedenarius, showing the undulations. 
14.—Side view of the same, showing the cellular markings. 


Alb T Hoey iy 


JOURNAL OF MICROSCOPICAL SCIENCE. 


DESCRIPTION OF PLATE V. 
To Hlustrate Mr. Hepworth’s Paper. 


Fig. 
1. —The three last joints of the tarsus of the foot of the Dytisews, which 
has attached to it— 
a. One large sucker. 
b, b. Two of smaller dimensions. 
c. Hairs, to the end of each of which a small sucker is attached. 
2.—One of the above-mentioned hairs, the dise of which is flattened singly 
into the same plane as the shaft; in their natural position they 
stand at right angles. 
3.—As No. 2, with the sucking-disc doubled upon itself. 
4.—Foot of large fly looking from above, showing hooks and flaps, the 
last being turned up a little at the edge, on which the tubules are 
seen with their trumpet-shaped extremities. 
5.—Enlarged view of a portion of No. 4 (a<), showing the points. 
6.—Back view of fly’s foot, isolated. 
7.—Front ditto. 
8, and 9.—Side ditto. 
10.—Foot of Horse or Gad-fly, having three flaps, furnished with tubules, 
very distinctly seen. 
11.—Foot of large fly, as presented to the eye from the under surface, in 
action, where the tubules are seen extending considerably beyond 
the margin of the flap, and the hooks are seen through the trans- 
parent flaps. 


DESCRIPTION OF PLATE VI. 


Illustrating Dr, Allman’s Paper. 

Fig. 

1, 2.—Starch from the Potato, treated with dilute sulphuric acid, after 
the prolonged action of weak tincture of iodine. 

3, 4.—Potato starch roasted slightly, iodinized, and treated with dilute 
sulphuric acid. 

5, 6.—Granules after the incipient action of hot water, showing the radiat- 
ing lines and fissures. 

7.—A granule of potato starch, which, after the removal of a slice, had 
been slightly iodinized, and then treatad with sulphuric acid. 
The granule is swollen, and the section is seen to have opened 
into an internal cavity. 

8—11.—Granules of starch. from Colchicum autumnale, exhibiting dlfferent 
appearances under the united action of sulphuric and acetic acid. 

12—17.—Semi-diagramatic views of the successive stages of expansion 
presented by a small starch granule under-the action of sulphuric 
acid. 


DESCRIPTION OF PLATE VII. 


1.—Starch of Musa paradisiaca (fruit) :—a, from the interior of the 
fruit ; b, the same viewed on the side; e, from the bark of the 
fruit ; c, d, f, seen in polarized light. 
2.—Euphorbia neriifolia, from the “‘ proper vessels :’—a and 6, viewed 
on the flat surface ; c and d, on the edge. 
3.—Carolinea princeps:—b, granule in which two distinct nuclei are 
enclosed in a common laminated envelop. 
4,—Philodendrum grandifolium (?). 
5, 6, 7-—/d. Beneath each granule in Fig. 6, may be remarked a layer 
of transitionary substance, which is not coloured blue by iodine. 
8, 9.—Dieffenbachia seguina. : 
10,—Batatas edulis:—a, two still separate granules, with the transi- 
tionary substance between them. 
11.—Costus spiralis. ; : 
12, 13, 14.—Costus comosus (?}—12, very young cells; in 14, may again 
be remarked the layer of transitionary substance. (Object viewed 
in polarized light). 


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ORIGINAL COMMUNICATIONS. 


On the AverturE of Oxssect-Giasses. By F. H. Wenanam. 


In the ‘ Quarterly Journal of Microscopical Science,’ for Jan. 
1854, I described a method of measuring the angular aperture 
of object-glasses (which had previously been made use of by 
Professor Amici). Since that time there has been some dis- 
cussion in relation to this subject, and as the plan that I pro- 
posed has been somewhat misunderstood, I will offer some 
further explanation. 

The principle consisted in placing a lens of short focal 
length over the top of the lowest eye-piece of the ordinary 
microscope, so that the focus of the emergent pencil, and that 
of the examining-lens should be coincident ; as thus adjusted, 
the microscope = converted into a kind ae telescope, and a 
view of objects, at an infinite distance, may be obtained. On 
rotating the microscope in a horizontal plane, taking the focus 
of the object-glass as the centre of motion, a distant object 
will be seen throughout the arc, that includes the aperture of 
the objective. When the object is bisected, or becomes very 
indistinct, this point will be the limits of useful aperture. 

The foregoing method has been objected to, on the ground 
that it is as much a measurement of field of view as aperture, 
but this is by no means the case, as the three eye-lenses form 
an optical combination that takes up the rays from the objec- 
tive at its posterior, or conjugate focal point; and but a very 
minute portion of the field lens of the eye-piece comes into 
action, for by substituting a stop of oniy 1-20th of an inch in 
diameter in place of the ordinary one, there is no difference in 
the resulting measurement,—in fact, the definition and dis- 
tinctness is rather improy = by it than otherwise. It is, 
perhaps, advisable to have a small stop at a short distance 
above the upper lens, as it will serve to keep the eye central. 

On first considering the modus operandi of this instrument, 
it would appear that as it causes the focus of the object-glass 
to be an infinite one, that there is no similarity between focal 
distance and the relation of aperture, and its effect on objects 
seen with a microscope under ordinary circumstances ; or, in 
short, that the aperture of the object-glass, in the form that it 
is usually understood, is apparently quite destroyed ; but it is 
a property existing in the object-glass, thus circumstanced, 

VOL, II, Q 


210 WENHAM, ON THE 


that it is still capable of receiving rays from distant objects, 
at every incidence within its aperture, and forming them into 
an image in the axis of the microscope, and it is a somewhat 
important feature in the principle, that we can ascertain the 
relative distinctness of the image at the same time that the 
aperture is being measured. if did not recommend this for 
the purpose of superseding existing methods of measurement, 
as Mr, Lister’s is perfectly accurate up to a certain number of 
degrees ; but it is more especially useful as a means of cor- 
roborition’ and for detecting errors that Mr. Lister’s plan will 
not always show ; for example, if an object-glass be selected 
with a large aperture that is surrounded by coloured zones, or 
a false ent: and measured with the examining-lens attached, 
on reaching the extreme, if this lens be removed, it is ‘hen 
simply Mr. Lister’s arrangement, and the clear light from the 
candle will be seen exactly to bisect the field of view ; but 
the coloured rings, and all other light that does not tend to 
form an image, will be outside, and not included within the 
aperture. 

I have found the method very serviceable, and am the more 
inclined to advocate it from the circumstance of its having 
been employed by Professor Amici, whose practical experience 
in the construction of object-glasses gives his opinion much 
weight. 

There is another plan of measuring apertures, contrived by 
Mr. Gillett, lately described hoes the Royal Society, and 
which has been announced, in the last Journal, as being, “a 
very perfect instrument for measuring the angle of aperture.” 
Supposing this assumes all preceding methods to be imper- 
fect, | will venture to give some reason for believing that it 
does not advance to such a standard. In describing the 
instrument, I infer that proper arrangements have been made 
for ensuring accuracy of motion and centering, and which fully 
answer the required end. 

The principle of action is as follows:—The object- 
glass, whose aperture is to be measured, is attached to an 
ordinary microscope body, fixed in an horizontal position ; a 
candle or lamp is placed close in front of the eye-piece, 
which is removed, and a cap, with a very small aperture, 
inserted in its stead, Under these circumstances the rays 
will pass through the lenses of the objective, and on finally 
emerging therefrom, will form a cone of light corresponding 
to its aperture, It is merely the simple micehvedient of the 
angle of this cone that Mr. Gillett has endeavoured to arrive 
at. To effect this, he has thought it necessary to employ 
another microscope, with eye-piece and object-glass complete ; 


APERTURE OF OBJECT-GLASSES. 211 


the focal point of which is made to rotate horizontally from a 
centre coincident with the axis and focus of the first micro- 
scope. The traverse of what may be termed the examining- 
microscope is indicated by an arc divided into degrees. This 
arrangement is not new to me, as [ have used the same for 
some years, for examining the oblique correction of object- 
glasses; but I always considered it to be too incorrect for a 
measurer of angular aperture, for the indication will be nearly 
as the sum of the two object-glasses ; ; or a large portion of the 
aperture of the examining-glass is added to the angle of the 
objective to be measured, and for tiiis there is no direct ratio. 
I have two object-glasses, one having a clear and definite 
aperture of 95°, and the other 90°, which, when applied 
together in this way, the indicated angle is very near 180°. 

Mr. Gillett appears to have discovered this source of error, 
as he has since attempted to remedy it by making an alteration 
in his instrument, which now somewhat differs from that 
originally described. To explain the improvement, I will 
consider the two microscopes and objectives placed with their 
axes in the same right line with foci coincident. A patch 
or stop is then placed over the front of the examining object- 
glass, which cuts off exactly one half of its area in a vertical 
position. Supposing this stop to occupy the left-hand side, 
the body of the examining-microscope is then moved to the 
right ; and when the light disappears, the number of degrees 
are noted. ‘The microscope is next moved back to its linear 
position, and the stop shifted round, so as to cut off the right 
hand half, and the degrees taken from this direction, added to 
the first indication, will give the angular aperture. This has 
thus to be obtained by means of a double traverse and shifting 
of the stop, which must be, to some extent, detrimental to 
accuracy. The last modification certainly reduces the aperture 
of the examining object-glass, but the same may also be done 
by using a stop with a very narrow vertical slit; the whole 
angle can then be taken at one operation, without sti teins the 
stop. I have tried both these arrangements with different 
assortments of object-glasses, but still find that there are some 
curious discrepancies. 

If every precaution be taken for obtaining an accurate 
result according to Mr. Gillett’s method, and then the instru- 
ment be reversed, so as to rotate or traverse the object-glass 
with the aperture to be measured, the same indication will be 
obtained, This, then, merely resolves itself into Mr. Lister’s 
method of measurement, and which will certainly perform 
better, and be more accurate, if the optical arrangement which 
intervenes, and only serves as an impediment to the free 

oe = 


212 WENHAM, ON THE 


passage of the light, is removed; in short, | am of opinion 
that Mr. Gillett’s complex contrivance will not prove seryice- 
able to the practical optician, If it is only the measurement 
of the angle of the cone of light emergent from the object- 
glass that he desires to accomplish, it may be accurately 
effected by means of a very simple and portable instrument, 
without any optical appliances whatever, as these only terid 
to falsify the result; but, for many reasons, | do not approve 
of measuring apertures in this manner. 

There is a paper in the Proceedings of the Royal Irish 
Academy for January 23rd, 1854, ‘ On a New Method of 
Measuring the Angular Aperture af the Objectives of Micro- 
scopes,’ by the Rev. T. R. Robinson. This is perfectly 
accurate in principle, and, as the paper contains some original 
information that leads the way to matters of much practical 
utility, I shall refer to it at some length. 

The mode of measurement cannot be better described than 
by using the author’s own words. ‘ As a lucid point in the 
focus of the objective sends out from the eye-piece rays nearly 
parallel, so light sent in the opposite direction through the 
microscope will converge at that focus, and then diverge in a 
cone, whose angle equals the aperture of the objective. If this 
cone be intercepted at right angles to its axis, by a screen, and 
the diameter of its section, together with the distance of the 
screen from the surface (focus) of the objective, be carefully 
measured, they give the aperture.” 

The luminous source may be either a camphine lamp or 
sunlight; the latter gives “a beautiful map of the objective's 
light territory,” and shows with remarkable distinctness the 
most minute errors of workmanship in any of the lenses, such 
as scratches, defective centering, dirt, &c. Another important 
application of Professor Robinson’s principle, is the measure- 
ment of the diminution of effective aperture that the object- 
glass sustains, when used upon an object immersed in balsam, 
or other medium; I do not think that this measurement can 
be so well effected by any other method than that here spoken 
of. The author mentions the fact that objects in balsam will 
be less illuminated than in the other way ; this alludes to the 
diminished angle of the illuminating pencil, and the same 
reasoning also applies to the aperture of the object-glass. 
The annexed diagram will show to what extent various angles 
of aperture are reduced, when viewing a structure immersed 
in Canada balsam. The exterior aperture is 170°, which is 
assumed to be the largest effective pencil that con be got 
through an object-glass ; this is,at once reduced to 82° or less, 
and the inner angle of 90° is brought down to about 55°. 


APERTURE OF OBJECT-GLASSES, 213 


I may here observe that a parallel plate of glass over an 
object, mounted dry, has no effect in reducing the aperture, for 


a 


the rays, after being deflected by the first surface, emerge 
again rae the second one parallel to their original direction, 
and all cony erge to a point at the same angle as at first, con- 
sequently the object is seen through the ae with an ‘angle 
of aperture the same as if it was not interposed. This is not 
the case when the object is immersed in a refracting medium 
with a plane surface, for the first, or single deflection, is not 
compensated for a second time, and hence the angle of aper- 
ture will be considerably reduced, according to the refractive 
power of the medium. Without resorting to theory to 
demonstrate what the reduction of aperture ought to be, I will 
show, practically, what it really is. In order to ascertain this, 
I employ ed a piece of polished plate-glass with parallel idles. 
0508 of an inch thick, which possessed very nearly the 
same refractive power as Canada balsam; I ascertained this 
by filling a plano-concave lens that I had by me, made of the 
same glass, with that material; when the concave side was 
placed on die plate of glass, on looking through them both, 
no optical effect could be dieiiry ered, 

The method of using the glass plate was as follows :—] 
first covered one side of it with a thin film of bees’-wax, to 
serve as a screen, and laid this downwards on the stage of the 
microscope. I then focussed the object-glass to be measured, 
exactly upon the upper transparent surface of the plate. 
Without shifting the microscope from its horizontal position, 
I next placed a cane before the eye-piece ; a bright circle of 
light appeared on the bees’-wax screen, the diameter of which 
I carefully measured ; an angle was taken from the circumfer- 
ence of the circle to the focal point of the objective (the 


214 WENHAM, ON THE 


distance being equal to the thickness of the glass plate). The 
angle thus obtained will represent the effective aperture of 
the object-glass for an object mounted in Canada balsam. 
The glass plate was now removed without disturbing the 
other adjustments, and a paper, or card screen placed in 
exactly the same plane as the bees’-wax film formerly occu- 
pied. The diameter of the circle of light was agaim measured : 
an angle taken from the circumference to the same point as 
before represents the aperture for an object mounted dry. 

This last is in strict accordance with Professor Robinson’s 
method. The following were the results :—A 1-12th, having 
an aperture of 146° on a object mounted dry, was reduced to 
75° on an object in balsam; an 1-8th of 125° to 71°; a 1-5th 
of 105° to 68°; anda 4-10ths of 90° to 56°. 

I have not had an opportunity of trying to what extent the 
aperture is reduced by the various other known media used in 
mounting objects. This may be very easily done by filling a 
parallel glass cell with the fluid, and it will exactly represent 
the conditions under which such objects are mounted, 

These experiments will readily account for the difficulty of 
discovering the markings or structure of a severe test when 
mounted in balsam ; for, as thus seen, it may be inferred that 
no aperture exceeding 85° can be made to bear upon it, and 
this is even supposing that the largest aperture object-glass 
that has ever been constructed is used. Such being the case, 
{ am somewhat puzzled at an announcement that appears to 
contradict this fact, coming from one that must be considered 
an authority in these matters. I refer to Professor Bailey, 
who, in a letter addressed to Matthew Marshall, Esq., dated 
January 20th, 1852, first speaks of an American object-glass 
of very large aperture (1723°), and its performance on the 
most difficult tests known, and then proceeds to say: “In 
all these cases (and, in fact, whenever I allude to a test 
object), | mean the balsam-mounted specimens. The dry 
shells I never use as tests.” This assertion seems to me to be 
extraordinary, and very like saying that an aperture of 85° or 
90° will do everything tbat is required. I have invariably 
found that when very difficult tests are mounted in balsam, I 
cannot discover the markings, and certainly, the reasons 
herein given will account for it. It is to be hoped that the 
American opticians have discovered some new and peculiar 
principle in object-glasses, that will render a smaller amount 
of aperture serviceable ; but however this may be, I think 
that Professor Bailey’s statement requires some further expla- 
nation. 

As the nature of the markings on test objects is now 


APERTURE OF OBJECT-GLASSES. 215 


exciting some degree of attention I will offer some remarks 
on the subject. The prevailing opinion with some theorists 
is, that the stria are rendered visible by the contrast induced 
by an inherent refraction of the siliceous prominences, throwing 
a portion of the rays from the source of illumination without 
the limits of the aperture of the object-glass, and thus causing 
the markings to appear opaque. This is, in effect, comparing 
the object to a piece of fluted glass. Now, if this were 
correct, if even the most easy of this class of objects were to be 
mounted in Canada baisam, the refractive index of this and 
silex being so nearly the same, every appearance of structure 
would be entirely obliterated ; but it is found not to be so, for 
the markings have the same appearance when in balsam as 
out of it; what want of distinctness there may be is partly 
accounted for by the effect of diminished aperture, which is, 
of necessity, reduced under this condition, and therefore, less 
of the radiations from the object are collected. 

I cannot persuade myself that any vital organism can be so 
devoid of structure, and so perfectly homogeneous as this 
theory would imply. I believe that all test objects are seen 
in the same way as any other transparent ones, by means of 
the different degrees of opacity of the parts. This opacity 
may arise from varying thicknesses, or from an imperviousness 
to light arisimg from colour, or the aggregated structure of the 
markings. In any of these cases refraction is not called into 
operation; and, further, I can show the markings on the most 
difficult tests when illuminated as opaque objects under such 
circumstances, that no light can be refracted from the striz 
into the object-glass. 

Those who adyance such speculations as these appear to 
forget that the definition of tests depends entirely upon 
aperture, and that this must be increased in proportion to the 
closeness of the lines or dots upon the object, and if the aper- 
ture of the objective is insufficient, no method of illumination 
will call them into view ; there is no occasion even to employ 
a microscope to ascertain this fact. In my paper on illumi- 
nation, contained in the last Journal, I have made comparison 
between the optical properties of the eye and a microscope ; 
this has been rather doubtfully received, for some cannot see 
the analogy ; but I must again refer to the same organ for a 
demonstration of the properties of aperture, 

If we place some small print against a wall, and retire to 
such a distance that the words are barely legible, and then 
apply to the eye an optical combination similar to an opera- 
glass, which will give it greater aperture, without increase. of 
magnifying power; it is most remarkable how this assists 


216 WENHAM, ON THE 


vision, and appears to illuminate the object, enabling the 
print to be easily read. 

The eye by itself is also a natural lens, possessing some 
amount of linear aperture, and if further comparison were 
wanting, the marginal rays show evident symptoms of imper- 
fect achromatism ;—but to return to the point in question. 
If we hold the blade of a penknife diametrically across the 
pupil, and examine the flame of a candle, it will appear 
double ; as the images formed at the opposite extremes of the 
pupil, or aperture, do not unite on the retina, this is igiite 
analogous to the diffracting spectrum seen in the microscope.* 
By using a piece of paper in the form of a cross, in place of 
the penknife, four images may even be obtained. The appa- 
rent mobility of distant objects, when a body is brought in 
a line with them at a short distance from the eye, may be 
attributed to the same causes. 

To illustrate the effects of the aperture of the eye in sepa- 
rating lines, suspend in a good light a piece of textile fabric, 
printed either in stripes or dots. Stand at such a distance off 
that the lines and interspaces are just clearly defined. Now 
examine them through a small perforation, made with a pin 
in a black card. The lines or dots will become invisible ; 
approach nearer and they will reappear; by substituting a 
smaller stop they will vanish as before, and again become 
distinct at a shorter distance. [ cannot go further than merely 
to mention this fact, which has been thoroughly investigated 
by Mr. Lister, who from the three data, of size of stops, 
number of lines in a given space, and distance of the eye from 
the object, has obtained very practical results, and ascertained 
the degree of aperture necessary for separating lines or spaces 
a certain distance asunder. In making comparison between 
experiments with the eye and microscopic object-glass, it is 
assuming angular and linear apertures to be the same in effect, 
of which fact there can be no question. 

For a demonstration of aperture I will again quote Professor 
Robinson’s paper :—“ The effect of angular aperture is merely 
an increase of illuminating power analogous to that of linear 
aperture in a telescope. Let O be a point of an object seen 
by an objective whose anterior surface is AB; this point, in 
case of a test object, may be considered as self-luminous, and 
equally so in every direction.” 

This exactly confirms what I have endeavoured to explain, 
that aperture is just effective in proportion to the quantity of 
radiations collected from the object. 


* See ‘ Quarterly Journal of Microscopical Science,’ for April, 1854, 
page 152. 


APERTURE OF OBJECT-GLASSES. 217 


All these facts must tend to prove that the separation of 
distances and definition of tests is entirely dependant upon 
aperture, and not upon illumination, as the Jatter will be quite 
ineffectual without the former. In concluding these remarks 
I may mention, that of two object-glasses of equal perform- 
ance, the best is that which does its work with the Jeast 
amount of aperture. Microscopists are but too apt to judge 
of the value of objectives, and select them entirely by the 
latter element. 

Some years ago I announced my opinion that 150° might 
be considered as the limits of useful aperture. This was 
asserted from practical data, and theory has led Professor 
Robinson to the same conclusion. There is little to be 
gained beyond this; and now that 160° and even 170° are 
not uncommon, I consider it quite absurd to suppose any 
wonderful effects will be produced from an extra 25°. Besides 
the small assistance and little light to be obtamed by means 
of the most oblique rays, they have another bad effect in 
giving a distorted image of the object. ‘This latter circum- 
stance alone has made me desirous of trying any method that 
would give the probable result of causing an object-glass to 
perform effectively with a less degree of aperture. Apparently 
this can only be accomplished through the reduction of the 
obliquity of the exterior rays, incident upon the first surface, 
by making the front of the anterior lens concave. For many 
years foreign glasses of this form have been sold, but their 
performance has not been such as to tempt an imitation of 
any peculiarity in their construction. Some time ago I gave 
this a trial, but not with that degree of care necessary to 
ensure a certain result. 

The concave form has been investigated mathematically by 
Professor Robinson with such good promise, that I have been 
once more induced to take it in hand, though he to some 
extent over-estimates the advantages to be gained from it; 
for he assumes the first surface to be dense flint, which would 
reflect a greater quantity of light, whereas this loss is lessened, 
as all our best object-glasses have of late years been made 
with triple fronts, with the first lens of crown glass. 

With excessive difficulty I have succeeded in making 1-8th 
of 138° with two separate anterior combinations, each giving 
the same degree of aperture and magnifying power. The first 
has a plane incident suriace. The second front is worked to 
a concave radius of 0°625 of an inch. On comparing them 
together I could not discover any appreciable advantage, in 
point of quantity of light, in favour of the one with the concave 
surface. I have tried the experiment with every degree of 


218 GORHAM, ON THE 


care, and consider that it sets this point finally at rest, and 
that it is a theory that does not tell in practice; I also under- 
stand that Ross has long ago arrived at the same result. <A 
front combination of this form considerably increases the 
difficulty of correcting the oblique pencils 


On the Maeniryine Power of Snort Spaces, illustrated by the 
transmission of Light through minute Apertures. By Joun 
Goruam, M.R.C.S.L., Memb. Soc. Arts, &e. : 


In the present communication it is my intention to furnish a 
few phenomena, illustrative of visual angle, of the magnifying 
power of short spaces intervening between the eye and the object, 
and of the inversion and multiplication of images by the simple 
transmission of light, without refraction, through small apertures 
in plane surfaces. As these illustrations are somewhat novel, 
I hope they may prove interesting to the readers of the 
‘ Microscopic Journal.’ 

The apparent enlargement of minute objects held and 
examined at very short distances from the eye, has received 
less attention at the hands of the writers on optics, than has 
the minifying power of longer spaces with respect to greater 
objects. We are more conversant, for instance, with the 
appearance of a church, or a tree, at one mile, than of a pin’s 
head at one meh; and, at these respective distances, we are 
more surprised to find the image of the latter enormously 
enlarged, than that of the former proportionally diminished, 
forgetting that the very same law is in operation in both 
instances, 

This comparative indifference with respect to the examina- 
tion of minute objects has arisen, doubtless, partly from their 
very insignificance, as we are accustomed, though not always 
justly, especially when examining those minute portions of 
the handiwork of God which bear upon them, without 
and within, the impress of the “hiding of his power,”* to 
consider little things contemptible, and beneath our notice ; 
partly, again, from the fact of our being able to avail ourselves 
of the assistance which a lens made of glass affords, when- 
ever we wish to examine any small body; and especially 
from the recollection that at any distance less than six inches, 
which is usually considered the shortest limit for distinct 
vision, a feeling of distress has always accompanied the 
attempt to distinguish the object, whilst at longer distances, 
the exertion is not only easy but pleasurable. In the former 


* Habakkuk iii. 4. 


MAGNIFYING POWER OF SHORT SPACES. 219 


case, too, as we shall have occasion to show, certain artificial 
contrivances are necessary to ensure vision at all, whilst, in 
the latter, the adjustment of the eye is without effort, and 
requires no adventitious aid. 

Whilst the transmission of light through small apertures, 
in the way hereafter to be explained, serves to show, in a 
conclusive and striking manner, that apparent enlargement of 
objects which accompanies their diminished distance from the 
eye; the variation in the size of the images at different ages, 
and in different eyes at the same age, and which is found to 
be very considerable, may, possibly, at some future time, 
assist in determining the relative refractive powers of the 
transparent media of the eye; and hence may come to prove 
of utility in the diagnosis of disease, although it is not my 
intention to insist upon the application of the phenomena 
elicited by these experiments, either to the one or to the other 
of the above important uses, in this present communication. 

For the few preliminary remarks about to be offered, some 
apology might be necessary, were it not that a difficulty 
seemed inevitably to connect itself with any attempt at 
arranging the subsequent portions without them. These 
remarks will be found, indeed, to consist of a mere repetition 
of those principles in optics, which, to a certain extent, and 
in particular aspects, have received abundant illustration 
from experiments, to prove their correctness, and make them 
intelligible ; and which, nevertheless, in other aspects, are 
calculated to afford new and important results,—for the laws 
of nature, so far from becoming deteriorated by a scrutinizing 
examination, always derive additional confirmation from the 
process. The visual angle, for instance, when applied to the 
investigation of objects at distances beyond ten inches from 
the eye, defines and measures the sizes of their images as 
depicted on the retina; and, when applied to the imitation 
of such images by delineating them on a vertical plane, it 
explains the art of perspective ; and these are such familiar 
examples of the application of a general law as scarcely to 
require specifying. But, on the other hand, if the magnitude 
of the visual angle is inversely as the distance, the size of the 
object remaining the same ; if bodies really do ¢ appear larger 
when brought very near to the eye, as we know they appear 
smaller when more remote; if, in short, the law of visual 
angle holds good for all distances, for the small as well as the 
great, it may be worth inquiring as to the kinds of pictures 
which are formed on the retina, when exceedingly small 
objects are held very near to the eye, so near, indeed, as to 
exceed the limits of distinct vision. That such objects present 


220 GORHAM, ON THE 


wondrously magnified images, if discerned at all, is evident. 
This, therefore, is just that kind of inquiry which, from having 
been instituted in comparatively a few cases only, serves to 
elicit new phenomena, of which it. will be one of the objects of 
this paper to furnish a few illustrations. 

That the apparent size of objects depends on their distance 
from the eye may be shown, with respect to short distances, by 
the following simple experiments:— Having closed an eye, place 
the forefinger of one hand across the palm of the other, and 
both at arm’s length. Now gradually bring the finger towards 
the open eye, and its image will be gradually and yet sensibly 
magnified ; and when the finger is about midway between the 
hand and the eye, its apparent size will be doubled. If a 
watch be used instead of the finger, the enlargement of its 
image will be very evident, and the palm of the hand which 
remains stationary will soon be completely hid by the appa- 
rent expansion of the watch. Whilst experiments of this, and 
of a like nature are, in themselves, of easy performance, and 
require no costly apparatus, yet they are not to be supposed 
the less useful on this account, although, there is reason to 
fear, this is too often the case; as if the mind were incapable 
of receiving any idea of the science of optics, excepting 
through the medium of finely-ground lenses set in burnished 
brass and polished mahogany. We are delighted, on the 
contrary, to discover the elements and exponents of general 
laws, themselves of the greatest importance, in combinations of 
such homeliness and simplicity. 

Take a couple of cards, the one four times as large as the 
other, that is, twice as long and twice as broad ; a card from 
a pack and the cover of a book will answer the purpose. Let 
the experiment be conducted as the preceding one, the small 
card being substituted for the finger, and the book-cover for the 
hand. Then, not forgetting to keep one eye closed, when the 
former is advanced to a station midway between the latter 
and the eye, both will appear exactly of the same size; in 
other words, the images of both will, as regards magnitude, 
be identical. Hence it appears that the linear magnitude 
varies inversely as the distance, and the superficial extent, or 
area, varies inversely as the square of the distance, for the 
finger was twice the length, and the small card four times the 
area, at half the distance. 

The explanation of this law is founded on the properties of 
the visual angle. Let AC, BC, fig. 1, be rays from the 
extreme point of the arrow AB, which cross within the eye 
somewhere about its centre at C; then the angle ACB is 
termed the visual angle. A glance at the figure shows that 


MAGNIFYING POWER OF SHORT SPACES. 221 


the greater the divergence of the lines composing that angle, 


Fig 1. 


the greater will be the are on the retina occupied by the 
image ab; and, also, the greater that image, the greater will 
be thie angle dictided by the lines AC, BC, the aes of visible 
direction, ee the angle a C bd is always equal to the angle ACB. 
The visual angle varies exactly as the are of the image, and 
as that angle may be formed with sufficient accuracy by draw- 
ing lines fon the centre of the eye to the extremities or boun- 
Pee of an object, it affords a convenient expression of the 
length or size of the image. If a second arrow, A’B, twice 
as long as AB, be placed parallel to AB, and at double its 
distance from the centre of the eye, then, by the properties of 
similar triangles, their visual angle will be equal, and their 
apparent magnitude identical. Conv ersely, if the two arrows 
be parallel, have the same visual angle, or apparent magni- 
tude, and one be twice as distant as the other, the more remote 
one must be twice as long as the other. The apparent mag- 
nitude of the same object, at different distances, may be 
inferred on the same principles. Thus, if AB approach the 
eye, remaining upright all the time, the visual angle will 
enlarge, and, at half its length, will appear double ; or, if 
AB sdaade an the eye, it w ill he seen under a smaller msi 
and appear proportionally smaller,—in fact, the apparent 
length of an object increases in oe same ratio as its distance 
from the point C, within the eye, decreases. Hence, to bring 
an object near the eye is to magnify its image. 

The degrees of divergence, or convergence, of the visual 
angle for smaller and larger distances of oe, object may be 
well shown by substituting black threads for the lines com- 
posing the angle. iene threads may be attached to the 
extremities of the arrow, which should be made of wood, as 
well as the plane on w ban it is intended to slide to and fro. 
Ten vertical lines may be drawn on the plane, dividing any 
given interval between the arrow and the eye into ten equal 
parts, which we will suppose to be inches. When the threads 


a2? GORHAM, ON THE 


emanating from the arrow A'B, fig. 1, are drawn through a 
hole bored at C, the arrow can be moved to and fro, at plea- 
sure, by traction at the knot from behind, and thus the 
gathering and spreading of the rays of the visual angle are 
well imitated. When the arrow is brought near to the eye 
the threads are seen to diverge rapidly from C, and when it 
is removed to a greater distance they are brought nearer 
together. During the passage of the rays toward C, they 
may be supposed to be transmitted through a plane of glass, 
1/1, held vertically before the eye, and on which the varying 
lengths of the image of the arrow, at different distances, may 
be measured. In this way it will be seen that, at ten inches, 
the space included by the visual rays (10 to 10), when they 
cut the plane of glass is very small, and this may be regarded 
asunit. At five inches (5 to 5), the space is exactly doubled, 
indicating that the image is twice as large at half the distance. 
At one inch the image is ten times as large, for the interval 
from 1 to 1 is ten times as great as the interval from 10 to 10. 
In all these cases the relative magnitude of the image, com- 
pared with its size when the object is ten inches distant, is 
found by dividing the distance for distinct vision of any 
object, and which is assumed to be about ten inches, by the 
new and shorter interval, produced at pleasure, by holding 
the object very near to the eye. Hence :— 


“At 10 inches the image will be == 1 
10 
» 9 ” ” 7. tee 14 
10 
7 1S ” ” Arc 1} 
10 ‘ 
Ap eats ” ” re = 1; 
10 
350 10 5 i gir = 12 
10 
bts ; ay Are 2 
10 
» 4 ” 3” = ae = 23 
10 
» 3 ” ” Riya 33 
10 
» 2 ” ” == Oe 5 
10 
Preey Bs a ie ae 10 


te) 


hl 
S 
os 
. 

I} 


MAGNIFYING POWER OF SHORT SPACES. 223 


10 
At } inch the image will be =~ = 40 
4 
10 
” 4 ” ” = Se = 80, &e. 
8 


The expression “to magnify an object,” common in optics, 
is an unhappy, because incorrect, mode of stating the fact, 
that the zmages formed on the retina of the eye are always 
magnified, as the distances of the objects by which they are 
produced are diminished. This should be constantly borne 
in mind. To say that an object appears larger is merely to 
refer it, by a mental process, to some imaginary and greater 
distance at which it looked smaller; and it is said to be 
magnified when it appears greater than it is usually found at 
those distances, ordinarily considered necessary for distinct 
vision, 

In using a single lens, the magnifying power, resulting from 
proximity of the object to the eye, and which is independent 
of the peculiar function of the lens itself, is commonly much 
underrated. When, for instance, we place an object in the 
focus of a lens held close to the eye, and having a small focal 
distance, and find its image magnified by the process, we are 
apt to merge the whole of these effects in the lens, and in its 
. so-called magnifying power, forgetting the new position of the 
object, its short distance from the eye, its enlarged visual 
angle, and the resulting increased magnitude of its image, 
The magnifying power of a lens is equal to ten inches,* 
divided by the focal length of the lens. But it is worthy of 
remark that this is just that power which is possessed by 
diminished distance, independently of a lens, and is found 
precisely in the same way; that is to say, by dividing the 
distance at which we see any small objects most distinctly, 
by the interval of nearer approximation to the eye. Nowa 
lens of half-an-inch focus is seen to magnify twenty dia- 


u 
meters, for —-=20; but it has been shown, by the properties 


of the visual angle, that the apparent dimensions of any small 
object placed at the same distance are identical. Hence the 
difference between the magnifying power of a single lens, 
used as such, and the magnifying power of a short interval 
between the eye and the object, is equal to 0; in other words, 
a lens would appear to accomplish nothing more, magnitude 
alone considered, than proximity, aided by the refraction of 
the humours of the eye, can effect. 


_* This is stated differently by authors; some supposing the shortest 
limit for distinct vision equal to ten inches, others to five. 


224 GORHAM, ON THE 


In giving such prominence to the powers of unaided vision, 
it must, however, be conceded that, in using a lens, the 
divergent rays are made parallel, and are thus prepared to 
enter the eye, and produce distinct vision. The outermost 
rays, too, those especially which are spread beyond an angle 
of 48°, would be reflected from the surface of the cornea, and 
altogether lost, and with them, a large quantity of light, 
otherwise appropriated to the illumination of the object, 
would disappear, were a lens dispensed with. Hence a lens 
of glass is useful in rendering parallel the rays which emerge 
from it after refraction; and it is more especially necessary, 
in gathering the most divergent rays, and thus bringing out 
the magnified image more distinctly by the larger quantity of 
light received from the object. 

These remarks are not at all likely to have any effect in 
deteriorating the value of such an useful optical instrument 
as the double convex lens, the utility of which, in some form 
or other, everybody acknowledges. They are made the rather 
to bring out by contrast the remarkable fact of the increase, 
which may be observed in the size of those images which are 
formed, by examining objects at very short intervals without 
a lens. A subject which is inviting, comparatively unex- 
plored, and doubtless worthy the attention of those engaged 
in optical science. 

It is supposed that those rays only which fall within an 
angle of 48°, or thereabouts, measured on the surface of the 
cornea, pass through it, and are refracted in their passage. 
Those which are not included within this angle are refracted 
by the verge of the cornea and the sclerotic coat. Rays in 
rapid divergence, however, may enter the eye, provided the 
point from which they emanate be very near or close to it. 
There is, probably, no easier method of proving this than by 
tracing the course of the rays of light which are transmitted 
through small apertures of known dimensions, through the 
humours of the eye to their final destination on the retina. 
For when the size of any object and its distance from the eye 
are known, the visual angle is also known, and hence the 
magnitude of the image formed on the retina is easily dis- 
covered. But these small apertures may be held im any 
position, either near to, or remote from, the eye; and thus the 
magnifying power of short spaces is seen to be capable of 
easy demonstration. 

This is shown in the following curious, and, as far as I am 
aware, previously unnoticed phenomena, which are based 
upon the transmission of light through small apertures, 

In order to exemplify this subject, let a number of common 


MAGNIFYING POWER OF SHORT SPACES, 225 


pill-boxes be procured, about half an inch in depth and one 
inch in diameter ;* and let small holes about the 1-40th of an 
inch in diameter, and at regular intervals of the 1-10th of 
an inch, be punctured through the bottom with a needle ;7 
as in Plate VIIL, fig. 1. 

These apertures are best made by carrying the needle from 
without to within, to prevent their size and shape being after- 
wards altered by friction. Then let small pieces of tracing 
paper be stuck over them with gum water, to prevent too 
much light entering the eye. For this, by contracting the 
pupil, would diminish the size of the image. Their trans- 
lucency may be still further slightly diminished by communi- 
cating a tint) with water colours, and for this purpose the three 
primary colours, red, yellow, and blue, may be used, for reasons 
hereafter to be specified. 

Combinations of these perforations related to the square, 
the pentagon, or the hexagon, may be left to the ingenuity of 
the reader. A few, partaking of the latter form, are sub- 
joined ; wherein the letters 7, y, 6, and w, refer respectively to 
the colours red, yellow, blue, and white. It may be premised 
that the tints should be laid on, as in ordinary tinting, coat 
after coat, until they become brilliant, without being at the 
same time opaque. 


(1.) (2.) (3.) 
- 

y b r Gab 
bor y y y y 
(ited? Phat: ate & 36 

“ 

(4.) (5.) (6.) 

bow 4 b ek. i: 
wea OD Baie ty b wb wy 
‘fo TY y r ce et es 
woboy iw A ints B wbw ob 

TG wis’ b ete > 93 


To these combinations we shall have occasion hereafter to 
refer, 


* The size marked two drachms used by chemists and apothecaries. 

T Sewing needles are generally sold in papers, which are numbered from 
one to twelve, according to their thickness. With a micrometer under a 
microscope, J examined the diameter of apertures made with needles from 
the papers marked Nos. 6, 7, 8, 9, and 10, and found them respectively 
equal to the 1-36th, the 1-38th, the 1-44th, the 1-50th, and the 1-70th 
of an inch. 


VOL. II. R 


226. : GORHAM, ON THE 


Now, if distance produced no change in the apparent mag- 
nitude of objects, the apertures should remain as needle holes ; 
and the colours should appear red, yellow, and blue, at all 
distances. But this is not found to be the case. On the 
contrary, when examined by looking through the bottom of 
the box from the inside, they are found to present the follow- 
ing phenomena :— 


1. Bringing the box within an inch or two from the eye 
these small inlets appear to expand into circular discs, which 
touch one another at their margins (see Plate VIII. fig. 2). 
And when held still nearer to the eye they become so much 
enlarged as to overlap at their edges (PI. VIII. fig. 3), But if 
the discs overlap, the colours must blend; and it is worthy of 
especial notice that this is actually found to take place. For 
when the three primary colours, red, yellow, and blue, are 
thus united in pairs, the secondary tints, orange, green, and 
violet are produced; and when the three primary tints all 
combine there is formed white light (Pl. VIII. fig. 3). 

These effects are demonstrable, and the colours are suffi- 
ciently distinct by the light of a taper held a few inches from 
the eye; but they are more brilliant and beautiful when seen 
in a room screened from the direct rays of the noonday sun 
by an ordinary white blind. 

2. Assuming each of these apertures to be an object, the 
circular disc is its enlarged image painted on the retina of the 
eye. It is difficult to obtain a correct idea of the size of these 
images without actually measuring them ; inasmuch as this is 
estimated very differently by different individuals. ‘To some, 
for instance, they appear to exceed an inch in diameter; to 
others they are as small as a fourpenny piece or a split-pea. 
My own imagination presents them as exactly resembling 
small coloured wafers. But it is probable that a cognizance 
of the actual size of the apertures themselves being associated 
with the perception of the image leads to an erroneous con- 
clusion as to their real dimensions. In every instance, how- 


MAGNIFYING POWER OF SHORT SPACES. 227 


ever, the magnitude assigned to them has been less, and never 
greater, than their true size. 

In order to measure them it is merely necessary to compare 
them, that is, the images, when the apertures are held at half 
an inch from the eye, with circles, or diameters of circles, of 
known dimensions, placed at ten inches. This is effected in 
a rough way by holding a measure horizontally ten inches 
from the eye, and noticing, when this is examined by looking 
through the aperture, how many inches or parts of an inch 
are included within the area of the circular image. When 
used for this purpose the apertures should not be covered with 
tracing paper, and the kind of light used should be specified. 

Now, by the properties of the visual angle it may be shown 
that when a small round opening, the 1-40th of an inch in 
diameter, or thereabouts, is held at ten inches from the eye, 
it presents an image equal to about the 400th of an inch 
across, and which appears as a mere speck. But when this 
same opening, or aperture, is examined at half an inch only, 
its image will be found so much enlarged as to cover a circular 
area two inches and a half in diameter, placed, in order to 
institute the comparison, at ten inches from the eye; and this 
may be easily proved by direct experiment. The apparent 
size of the disc has therefore undergone an immense increase 
by this simple process of bringing the aperture nearer to the 
eye. It is, in fact, magnified a thousand diameters. For— 


ta inch ; 23 inches :: 1 : 1000. 


But this gives the rate of increase in one dimension only. 
Hence, if our calculations are carried a little further, we shall 
find the entire area of the disc magnified one million times. 
For :— 


Area of circular disc (a) 24 inches in diameter = 4°90873 
” ” (B) a0 », » = 000004908 
Then area of (a) : area of (8) : : (diameter)? : (diameter)* 
ee ee 25 | 40000 _ 
. ir i a 4 or al = 1000000. 

Thus it appears that the image which is produced by 
examining a small hole made with a needle is magnified one 
million times by simply diminishing its distance from ten 
inches to half an inch from the eye. 

3. These discs are invariably diminished in size when, 
from any cause, the intensity of the light is increased, While, 
therefore, on viewing them by the direct rays of the sun, their 
margins scarcely touch, by diffused daylight, or the light of a 
taper, they directly overlap. This result is clearly owing to 

R 2 


228 GORHAM, ON THE 


the alternations of size of the pupillary aperture: for this 
circular opening expands when the light which enters the eye 
is diminished, and contracts when the light is increased.* 
For the same reason the discs always become smaller when 
the other eye is opened, and again resume their size when it 
is closed. This effect is instantaneous, and may be repeated 
again and again, as often as we choose to make the experi- 
ment. ‘These rapid alternations of size in the circles, result- 
ing from the alternate contraction and dilatation of the pupil, 
show, in a striking manner, how the quantity of light which: 
enters the one eye regulates and controls the pupillary aperture 
of the other, and thus points to the necessity for shading both 
eyes in those diseases where it is important to exclude the 
light from either. 

4, That the pencils of light emanating from these apertures 
cross within the eye, come to a focus, and form an inverted 
image at the bottom, may be inferred from the fact of their 
visual angle being less than 48° when they are examined at 
half an inch. And that the image itself is really inverted 
may be proved by making a second very small aperture close 
to the edge of the larger one (fig. 4). The image of this 
double aperture is an ovate disc seen in its true or erect 
position (fig. 5), in which position it would not be seen were 
it not inverted on the retina, 


Fig. 4. 


The visual cones emanating from these apertures, there- 
fore are thus disposed (fig. 6) and transmitted through the 
humours of the eye, by which they are rendered convergent, 
and so come to a focus at the bottom. 

5. It is worthy of notice that the imnermost rays of these 
cones of light, which we have just examined, cross each other 
almost directly after proceeding from their radiant points 
towards the eye: and, as they do not again intersect during 


* The ordinary dimensions of the opening of the pupil, seen through 
the cornea, are from the 0°27th to the O°13th of an inch; and its mean 
size is the 0°20th of an inch. 


MAGNIFYING POWER OF SHORT SPACES. 229 


their passage through its humours, the image of any small 
object held within the ; 

angle acb should be s 

formed erect on the 
retina, and should be 
seen, consequently, in 
an inverted position. 

That this is the case 
may be proved by direct 
experiment. For this 
purpose I mounted a 
small cross about the 
tenth of an inch in 
length, and the twentieth of an inch broad, cut from a sheet 
of coloured gelatine, on the centre of a glass slide, with gum 
water, so that it might be used at pleasure. On holding this 
small cross between the eye and the aperture a small inverted 
image of it is seen, as if drawn in the centre of the disc. 
Moreover I noticed generally, that the images of all objects 
which were so placed as to subtend the angle ach were seen 
in an inverted position. 

To illustrate this, let 7 (fig. 7) be the radiant points pro- 
ceeding from the 
aperture p, in the 
bottom of the box, 
6b, and let rab 
rab be the cones 
of light passing 
through the slide 
of glass s and the 
eye ¢, to form a 
circular image on 
the retina 7. Let 
the cross which 
occupies the centre 
of the slide be suf- 
ficiently small to 
subtend the angle 
ach; then the rays 
of light caande “b, 
which Mldmikate 
its extremities, are 
transmitted to the 
retina without in- 
tersection, form- 
ing there an erect 
image 7, which is seen in an inverted position at p. 


Fig. 7. 


230 GORHAM, ON THE 


A rude modification of this experiment may be made with 
a pin, a cork, and a small pillbox. This latter should have 
a small hole, about the fortieth of an inch in diameter, made 
in one of its sides with a needle ; and a circular piece, about 
the eighth of an inch 
in diameter, should be 
excised at a point ex- 
actly opposite the first 
from the other side. 
The pin is now stuck 
into the cork and the 
box inverted over it, 
the centre of each open- 
ing and the head of the 
pin being all in one 
straight line (fig. 8, 
aa). On __ looking 
through the small hole 
the pin is seen much magnified ai in an erect position; but 
when examined through the larger opening it appears inverted, 

6. In pursuing these investigations it occurred to me that, 
whilst in the polyscope, or ordinary multiplying glass, the 
multiplication of the images is effected by causing the rays 
which proceed from the object to travel towards the eye in 
as many different directions as there are images, by refraction : 
the same result might be obtained without a glass, by trans- 
mission, For it was clear, that if it be possible to view the 
same object by rays of light, all emanating from different 
points, and concentrating themselves in the centre of the eye, 
such an object must appear multiplied. Hence, on examining 
a small cross, similar to that which was used in the last 
experiment, under the light admitted through six apertures, by 
holding it between them and the eye, I was gratified to find 
my anticipations realized ; for six inverted images of the cross 
immediately appeared: one being painted on the centre of 
each disc, as if by magic, 

This phenomenon was scarcely less interesting than either of 
the former, for it seemed to present a new and anomalous position 
of the object, with respect to transparent media, in the forma- 
tion of multiplying images ; in short, a new kind of polyscope 
was discovered, having properties distinct from those belonging 
to an ordinary multiplying-glass, In order to point out the 
difference between these two optical instruments, it must be 
borne in mind that, in a common multiplying-glass, the object 
to be multiplied is placed on one side of the glass, and the 
eye on the other, while the images are conveyed to the eye by 
the aid of the refracting power of the glass. Thus, in the 


Fig, 8, 


MAGNIFYING POWER OF SHORT SPACES. 231 


multiplying-glass with three faces, a bc, fig. 9, let the object 
be placed at 0, and the eye at ¢; then the new images, ¢7, are 
seen in the direction of the emergent rays, ae, be, after refrac- 


Fig. 9. 


tion; that is to say, the rays ao,bo, emanating from the 
object at 0, converge on the opposite side of the glass, and 
enter the eye at e¢, which thus perceives three images instead 
of one: the first being that of the object in its real position, 9, 


and the other two in the directions ez and e7. But the same 
result may be obtained, as we have said, without refraction, 
by holding a small Fie. 10. 


object nearly close 
in front of the eye, 
and inspecting it 
by the light trans- 
mitted through 
small apertures, 
when the number 
of the images will 
be found to coin- 
cide with that of 
the apertures, and 
will be seen in the 
direction of the 
pencils of light 
which travel 
through them. In 
order to illustrate 
’ this, let abc, fig. 
10, be three small 
apertures, about 
the 1-40th of an 


232 GORHAM, ON THE 


inch in diameter, and the 1-8th of an inch apart, made in one 
straight line in the bottom of a pillbox, and let 0 be a small 
cross of gelatine, as before described, or any other small, 
transparent, well-defined object mounted on a slip of glass. 
Let e be a section of the eye, and ac, the images painted 
on the retina: these images will be circular discs, having, 
in the centre of each, an inverted image of the object 0, as 
shown in the opposite figure (11). | 

Hence the bottom:of the box, which contains these openings 
a, b, and ¢, is similar to a multiplying-glass in producing as 
many images of the object as there are transparent facets in 
the glass, but unlike in these important particulars, that those 
facets are all in the same plane; that the light is not refracted 
by them, but merely transmitted ; and that the eye and the 
object are both on the same side, that is, in front, of the mul- 
tiplying medium. 

In this experiment it may be instructive to notice: 1. The 
rectilineal direction of the visual cones in their passage from 
the apertures to the eye, each of which, although intersecting 
the others, and being crossed by them again and again, travels, 
in one undeviating course, until it falls upon the cornea, and 
is finally brought to a focus on the retina, thus defining the 
shape of the images. 2. The last direction of the pencils of 
light which fall upon the cornea, determining the position of 
the images in space, for an object always appears in the 
direction in which the Jast ray of light comes to the eye. If 
the light which comes from a star were bent into fifty direc- 
tions before it reached the eye, the star would, nevertheless, 
appear in the line described by the ray nearest the eye. 
3. The influence of proximity of the object to the eye in 
increasing the magnitude of the image. 4. The perception 
of many images, of only one object, that object being ren- 
dered visible not by one pencil of light only, but by many 
pencils in different directions, explaining the cause of the 
multiplication of images; and 5. The peculiar arrangement 
and disposal of the rays, during their passage from the aper- 
tures to the eye, in producing an erect retinal imaye, and an 
inverted mental one :—for these are so many phenomena, each 
and all of which serve to show how the laws of light may be 
illustrated by means the most simple. 

7. The multiplication of images, referred to in the last par- 
agraph, has been shown to result from the simple transmission 
of light through small apertures.. But there is a second case to 
be noticed, wherein double images are produced by refraction, 
that is, refraction during the passage of the rays through the 
eye, and without the intervention of a lens of any kind. 


MAGNIFYING POWER OF SHORT SPACES. 233 


These double images are seen on holding a small object behind, 
instead of in front of, the apertures ; and when seen, it is to 


Fig. 11. Fig. 12, 


be noticed that they always occupy that oval space formed by 
the mutual intersection of the circular discs, fig. 12, s. 
In order to explain this, let two small holes (a a, fig. 13) the 


1-70th of an inch in diameter,* and the 
1-20th of an inch apart, be made in the 
bottom of a box, and let a pin, p, be held 
behind the box, at the distance of an inch 
or two. On looking at this through the 
apertures, a double image of it will be 
seen atziz. When the pin is withdrawn 
to a considerable yet certain distance, say 
p, 2 Single image only will be noticed, the 
rays coming to a focus at f; but on bring- 
ing it nearer, the two again become visible. 
It is evident that these phenomena are to 
be referred to the refraction of light, during 
its transmission through the humours of 
the eye. 

The refracting power of the eye varies 
at different ages, and in different indivi- 
duals of the same age ; and it would appear 
that its intensity may be measured by ascer- 
taining the distance at which any small 
object, such as a pin, produces a single 
image, when viewed through two apertures, 
in the manner just described ; for when the 
distance is known, the direction of the rays 
being determined by the interval of the 
apertures, the visual angle is also known ; 


Fig. 13. 


and when one image only is seen, the rays by which it is 
formed are brought to a focus exactly at the bottom of the 
eye, thus measuring the refractive power of its humours. 


* Such apertures can be made with a needle marked No. 10. 


234 OSBORNE, ON CLOSTERIUM LUNULA. 


But if the same object, at precisely the same distance, were 
examined by another eye, and if two images were seen instead 
of a single image, there is good reason to infer that, in the 
latter case, the transparent media of the eye would be endowed 
with powers of refraction greater than in the former; hence 
the relative refracting power of two eyes may be found by 
measuring the intermediate space between two points, say p 
and p’, at which the same object appears as one, that is, forms 
a single image in two different individuals. 

I have, in this paper, laid before my readers an account of 
several new phenomena which have occurred to me whilst 
investigating some of the laws of optics; in doing which it 
accorded with my design and professional avocations to be brief 
and perspicuous, rather than to write an elaborate essay. On 
a careful perusal, especially of the sixth paragraph, it will, 
doubtless, not have escaped notice, that certain of the results 
involve principles bearing a direct application to the con- 
struction of one or two amusing and instructive optical instru- 
ments, not heretofore invented. But I shall beg to reserve a 
more particular description of these for a second paper. 


(To be continued.) 


On Ctostertum Lunuta. By the Hon. and Rey. S. G. 
Ossorne. Communicated by JaBez Hoae, Esq. 


“¢T HAVE now examined with great care more than one hundred 
specimens of C. Lunula. I will give you the result as 
impressed upon my own mind. 

‘“‘T believe this plant (if plant it be) consists of an outer case, 
of a hard and almost insoluble material, having at each end 
a minute aperture, opening to receive the water in which it 
lives. This case is divisible in the centre ; about the middle 
of the concave side there is some difference in texture or con- 
struction, for the slightest pressure will rupture it, allowing 
the endochrome to escape. 

“The endochrome itself is contained in a very thin mem- 
branous sac, free of the outer case, except, perhaps, at one or 
two spots about the centre, where ‘the streak of light is per- 
ceptible. This sac is highly elastic, and often by its con- 
traction or expansion alters the appearance of the plant. At 
its extremities it has apertures to receive the fluid brought 
through those in the outer case. 

“The endochrome, consisting of green matter, changes its 
appearance with the growth of the plant ; sometimes it nearly 


OSBORNE, ON CLOSTERIUM LUNULA. 235 


fills its investing membranous sac, at other times it leaves a 
good deal of it, as well at the ends as at the margin, empty. 
At the extremities of the green matter there are certain bodies 
acting with a ciliary movement within what has been called 
a chamber, being towards the point of the membranous sac: 
certain bodies, apparently of the same kind, occasionally 
separate from the endochrome in a small mass, appearing at 
the extreme end of this so-called chamber, or at the side close 
to the end ; these also impart a ciliary movement to the water 
within the sac, around them. 

“ Over the whole surface of the endochrome I can not only 
trace a distinct circulator, but the action of cilia. In one 
specimen, which I had the pleasure of showing for some 
hours to Mr. Mansel, of Spetisbury, a neighbour of mine, 
devoted to the microscopic observation of the Desmidiew and 
Algz, the bunch of ciliary matter had got to the extreme end 
of the internal sac;;which was so expanded as to fill up the 
whole point of the outer case ; they thus abutted on the outer 
aperture opening upon the water; the result was an evident 
action on the water, in which we could see the points of cilia 
working externally to the point of the plant; the water was 
thrown in jets quite as far as in the annexed sketch. I use 


the word jets, for it was not like any other action on water 
I have ever seen produced by cilia. The water was spirted 
in globules, similar to what one would expect to see in a 
microscopic fountain. We had the pleasure, with the mem- 
bers of my own family, of watching it for many hours. I 
used a 1-inch of Ross’s, a }-inch of the same maker as illu- 
minator, with a prism, and the usual bull’s-eye condenser ; the 
light was taken from a strong moderator lamp; the eye-piece, 
a very powerful and clear one, made for me by Mr. Ladd. 

‘* As to the circulation (no new discovery) I never find any 
difficulty in tracing its course. My theory is this :—there are 
cilia, more or less in number, over the whole endochrome ; 
peculiar clusters of them at its extremities; these keep up an 
action, attracting and repelling fluid drawn to them, through 
the apertures in the internal and external cases. The fluid, 
when received within the membranous sac, is impelled over 
the whole surface of the endochrome by the cilia. Between 


236 OSBORNE, ON CLOSTERIUM LUNULA. 


the outer case and the inner one currents are kept flowing, 
receiving, as I believe, their impulse from the same action. 

** When we saw the ciliary action external to the plant, as 
described above, we saw that the marginal currents had ceased: 
to flow. I infer from this, that by the accidental pressure of 
the glass, the active mass of ciliary bodies had got so close 
to the end of the sac as to press out to the edge of both aper- 
tures, that of the sac, and that of the external case. The 
machinery thus displaced gave us that hydraulic action outside 
which was proper to the interior of the plant; 1 assume that 
the normal action of these cilia would jet what water they 
did not send over the endochrome back with some force 
against the interior of the outer case, and thus force it into 
the currents we see. 

“If I put a specimen on the stage, cover the stage so as to 
exclude the light, use the parabolic illuminator, with the 
direct light of the sun; in certain focal positions I see what 
appears to be cilia working evenly and continuously along the 
whole external margin of the plant. I am inclined to believe 
it is not so, that this is some ocular deception, and that these 
cilia, so seen, are within the outer case; it may be that there 
are cilia on the external surface of the membranous sac, as 
well as over the endochrome. More practised observers, with 
higher powers, may yet determine that; of the existence of the 
cilia throughout the plant there can be no doubt, and no 
object I have ever seen will bear comparison with this, when 
beheld under a sun light; it is, indeed, a Godlike work, as 
wonderful as beautiful. 

“It is very seldom that I can trace a current up one margin 
and round the point down the other; these currents seem to 
me as the rule, to pass from the point, when they reach it, 
down to the centre of the spot, where the cilia are seen 
terminating the endochrome. 

‘‘] have just seena specimen,* but not of C. Lunula, of this 
shape ; the shell of the 
plant had formed itself 
into two halves, one over- 
lapped the other, its out- 
line quite clearly defined ; 
in these two divisions we could see the circulation going on, 
as I have dotted it, round each segment separately, at the 
circular extremities. ‘The loose bodies seen in the chamber 
of C. Lunula have very generally cilia, and are, I believe, 
zoo-spores ; loose pieces of endochrome are sometimes brought 
round in the current, but these are easily distinguished ; 1 

* O, Leibleinii. 


OSBORNE, ON CLOSTERIUM LUNULA. 237 


have never seen anything like true cyclosis, 7. ¢., molecules, in 
circular movement within the so-called chamber. Although 
I have purposely burst many specimens when under view, I 
have never seen the green matter, in passing out, get between 
its own sac and the outer case. I leave the above at your 
disposal, hoping it may prove interesting, only claiming for 
it the attention due to the working of one who is but a tyro 
compared to many of you, though a hard-worker, and devoted 
to the studies the microscope so abundantly affords, of his 
Maker’s works. 

“ Are you aware that the Arthrodesmus Incus drawn in the 
books should be drawn as represented in the 
annexed figure? It has avery beautiful hyaline {{~ 4 
membrane stretching from point to point, cut } 
at the edges, something like the Micrasteria. 

A moment’s good manipulation under a high y 
power will prove it, especially with the aid of Uf vt NE 
colouring matter in the water. 

“ Why is Xanthidium armatum drawn without the sete, 
clearly to be seen between its processes ? 

“*T can discover cilia in the Pentium, Docidium, and Xan- 
thidium ; but not to the same degree of clearness as in the 
Closteria ; circulation can also be seen in some other Desmidiee. 
Make any use you please of this, I fear, lame account of what 
has been more interesting to work than it is easy to describe, 
or, I fear, likely to interest those who read it.” 

Having received a liberal supply of specimens from the 
Rey. Mr. Osborne, I have great pleasure in confirming bis 
observations with respect to the ciliary motion. I made use 
of Shadbolt’s glass parabolic reflector, with an 4-inch object- 
glass and a deepeye-piece. The sun was shining at the time, 
and I threw a ray upon the Closteriwm, when, to my delight, I 
saw the whole frond brilliantly glittering with the moving 
and active cilia, as represented in the drawing, fig. 1; whilst 
in the cyclosis numerous zoo-spores were most actively moving 
about by the same agency. It is impossible to imagine a 
more beautiful object and spectacle than was here presented. 
When the sunlight, falling on these little bodies, warmed 
them into life and motion, the rapid undulations produced by 
the action of the cilia, illuminated the whole frond with a 
series of most charming and delicately-coloured prismatic 
fringes or Newton’s rings. 

The motion and distribution of the cilia must be seen by 
the aid of the direct sun-rays and parabola; for, although | 
tried every other mode of illumination, and, with Mr, 
Brooke, used Gillett’s condenser, yet neither of us noted satis- 


238: OSBORNE, ON CLOSTERIUM LUNULA. 


factorily their situation and distribution until we resorted to 
the parabola. 

At the same time the circulation may be most accurately 
observed to take place over the entire surface of the pond. 
The stream is best seen to be running up the external margin, 
just internal to a row of cilia with another taking a contrary 
direction next to the serrated ciliary edge of the endochrome, 
the whole being restricted to the space between the mass of 
endochrome and hyaline integument, passing above and 
around the cyclosis, but not entering into it. Mr. Bower- 
bank appears to have observed this a few years since, and 
Mr. Ralfs in describing it, says:—‘I at first supposed that 
the circulation was confined to the margins, nor did I per- 
ceive it elsewhere until Mr. Bowerbank adjusted the micro- 
scope, and showed me the motion extended over the whole 
surface of the endochrome.” The Rev. Mr. Osborne has just 
sent me a drawing, with description and other observations, 
which may prove interesting to microscopists. 


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ain THTTTTT AULT MULT TATA LUATLAL AAMT LTT ATH HLA) TNS 
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Intended to show the cilia surrounding the frond ; by mistake of the engraver 
the outer hyaline case has been cut away. 


OSBORNE, ON CLOSTERIUM LUNULA. 239 


The Rev. Mr. Osborne, in a letter to me dated May 31, 
says :— 

‘I have scarcely failed in one attempt to see the circula- 
tion and ciliary motion in the Closterium Lunula; | tried to- 
day heating a little water, by putting a small bottle in a cup 
of warm water; the effect seemed to retard the circulation, 
but to make the globules larger. I have traced it over 
the whole extent of the endochrome, but it is best seen at 
the convex side, a short way from the edge. I am more 
than ever convinced the cyclosis is the waving of attached 
tongues of cilia. ‘The specimens are capricious in the results 
they afford; they show best when the sun has been on the 
jar for a time. I have watched the movements of the globules 
in Vailisneria, Nitella, &c., and they are to me altogether of 
a different nature to that in the Closterium, &c. To my eye 
there is no real analogy between this circulation and that in 
the aboye plants ; but there is much more with the branchial 
action in the mussel. 

‘* When the endochrome is of a rich dark green, I find the 
chamber at the extremity very plain and defined, with its cilia 
very active, margin of hyaline case very clear and broad, and 
the circulation most evident, As the endochrome gets of a 
lighter colour, it pours a greenish matter towards the edges, 
excluding a sight of the former circulation, but yet itself 
showing a more sluggish movement. The chamber gets 
smaller; the cilia are barely seen. The next stage is without 
the sporangia, or as represented in the drawing fig. 8. The 
sporangium at a@ was of a brownish colour, with the endo- 
chrome broken on each side of it. The circulation was very 
plainly seen in two or three currents all round the edge. 
At b I could easily trace it in several rapid streams coming 
from each side and then turning down, as if it was attracted 
to, or had some channel under the detached piece of endo- 
chrome, c. ‘There were several clear round globules, whose 
course was easily traced; they seemed carried about by the 
regular streams to the end, from whence they returned and 
joined one or other of the streams passing back along the 
edges. The cell in which the cyclosis, or cilia, are usually 
seen, was not to be made out, nor could we see anything like 
the moving bodies I believe to be cilia. At d the same 
streams were visible, and had the same appearance as at 4, 
coming up to the sides where the arrow is placed, then return- 
ing towards the centre of the endochrome, seeming to pass 
under it, the back stream beginning ate. The hyaline edge 
was yery narrow, the endochrome having disappeared from 
the ends, there remained large spaces without chamber or 


240: CURREY, ON TWO NEW FUNGI. 


cilia, but with a distinct circulation going to the centre of the 
apex from each side in many streams. I used a }-inch Ross 5 
having no good eye-piece to my travelling instrument, I 
applied the upper half of an excellent telescope of the same 
maker’s, which answered very well.” 

I may also state that I found the ciliary motion going on in: 
all the specimens I examined ; and the water supplied was 
exceedingly rich in this class of objects, containing Closterium 
Lunula, C. acerosum, C. didymotocum, C. costatum, C rostratum, 
and C. setaceum. 

Docidium nodulosum and clavatum, Pentium. digitum, and 
closteriotdes, all well showing the circulation and ciliary 
movement. Anthrodesmus incus, some good specimens show- 
ing an active motion of cilia around the spines. This was 
better and very beautifully seen in specimens of the Xanthi- 
pium fasciculatum and armatum, Cosmarium undulatum, C. 
pyramidatum, and C. margaritiferum, a very active internal 
motion of granular masses and ciliary motion surrounding the 
external margin. 

Euastrum oblongum, Micrasterias denticulata, rather more 
flattened in its longest axis than those represented by Mr. 
Ralfs, circulation of granular particles around the internal 
cells evidently of a ciliary character. 

Didymoprium Borreri and Desmidium quadrangulatum, with 
many other specimens, all showing ciliary movements of a 
more or less ‘active character imperfectly represented in the 


drawing, figures No. 1 to 7, 


On two new Funer. By Freperick Currey, M.A. 


I nave lately met with two minute Fungi, which do not 
appear to have been hitherto described, and as their micro- 
scropic structure is curious and interesting, the following. 
account of them may be acceptable to some of the readers of 
the ‘ Microscopical Journal.’ 

The plants are figured in Plate IX. Figs. 1 and 2 repre- 
sent specimens of one of these Fungi drawn to the natural 
size; figs. 3 and 4 represent the same specimens drawn with. 
the camera lucida, under a two-inch object-glass ; and fig. 5 
represents the capillitium and spores, drawn in the same way, 
with a z-inch object-glass, This Fungus grew very sparingly: 
on the inner bark of a dead tree. The peridium is aregular 
in shape, varying much in different specimens, but in almost. 
all it is more or less serpentine, following the sinuous cavities: 
between the wood and the bark. In colour the peridium 


CURREY, ON TWO NEW FUNGI. 241 


resembles that of many of the T’richiz, and one of the most 
perfect of the specimens in my possession bears considerable 
resemblance externally to Trichia reticulata, or, as it is now 
called, Trichia serpula, figured by Dr. Greville in the Scottish 
‘ Cryptogamic Flora.’ An examination of the capillitium, 
however, proves that the plant does not belong to that genus, 
but would rather lead to the supposition of its being allied 
to Arcyria, the capillitium being somewhat reticulated and 
minutely denticulate. But it will be observed, that the 
dehiscence of the peridia is longitudinal, and not circum- 
scissile, as is the case with Arcyria ; nor does the capillitium 
appear to be persistent. 

Another characteristic of the present Fungus is, that the 
capillitium (fig. 5) is of two kinds, the spores being attached 
to the more delicate one, which may be seen in fig. 5 as a 
narrow yellow line connecting the spores, but of which it is 
almost impossible to give a correct idea in a drawing, on 
account of its excessive fineness and transparency. The 
coarser capillitium is densely interwoven and somewhat reti- 
culated, but much of the apparent reticulation arises from the 
passage of the threads over and under one another, and does 
not result from actual conjunction. The existence of a double 
capillitium has hitherto, so far as 1 am aware, been observed 
only in Leocarpus vernicosus (Diderma vernicosum of Fries), 
from which the present Fungus is distinguished by the absence 
of the double peridium. The coarser capillitium is swollen 
here and there, and the swellings are of a darker colour than 
the rest of the threads. These swellings occur usually in the 
course of the threads, but they seem to be sometimes terminal ; 
and one of those represented in fig. 5 has the appearance of 
being in the act of discharging small granules from a hole at 
its apex. 

From the above description it will be seen that this Fungus 
unites some of the characteristics of three different genera not 
far removed from one another, viz. Trichia, Arcyria, and Leo- 
carpus (or Diderma); whilst, at the same time, there is not 
suflicient similarity to admit of its being classified under any 
one of them. If it has not been hitherto observed I should 
propose the name Ophiotheca, in allusion to its flexuous 
peridium. ‘The colour of the spores would lead to the adop- 
tion of ‘chrysosperma, or some analogous epithet, as its 
specific appellation. 

Figs. 6 and 7 represent the other Fungus to which this 
paper relates, drawn to the natural size ; and fig. 8 shows a 
single specimen, laid open with needles and magnified 220 
diameters. From the different opinions which I have received 

VOL. II. Ss 


242 CURREY, ON TWO NEW FUNGI. 


respecting it there seems to be considerable doubt as to its 
affinities. It appears to me to be almost identical with 
Trichoderma, consisting, as it does, of a central mass of spores 
surrounded by a dense covering of hairs. It differs from 
Trichoderma in the jointed nature of the hairs, and in the 
colour of the spores, which, in fresh specimens, is a brilliant 
yellow. This plant was found upon fragments of dead leaves 
and sticks lying on the ground in a very moist, almost muddy 
spot, ina wood. The specimens grow sometimes singly, and 
sometimes in small patches. If a new genus be constituted 
for it, I think that, from the jointed nature of the hairy cover- 
ing, é Arthroderma’ would be an appropriate name. 


DESCRIPTION OF PLATE IX. 
Fig. 
1 and 2.—Natural size of one of the Fungi. 
3 and 4.—The same magnified by a 2-inch object-glass. 
5.—The capillitinm and spores under a }-inch aga 
6 and 7.—Natural size of second Fungus. 
8.—Spores and hairs in its interior under a power of 220 diameters. 


( 243 ) 


TRANSLATIONS, &c. 


On Contractite Tissues in the Hymenomycetes. By Prof. 
Hermann Horrmann. Botanisch. Zeit. (Dec. 9th, 1853.) 


Tue annulus on the stipe of Agaricus muscarius is free at the 
lower margin, hanging down in folds; above it blends more 
and more intimately with the outer surface of the stipe, and 
ultimately can no longer be definitely distinguished from it. 
The upper side of this frill-like investment of the stipe, or 
that which is directed towards the angles of the gills, is 
covered with a delicate loosely-felted tissue, which is, at first, 
white, but, as the fungus grows, assumes a yellowish tint. 
This covering is especially well developed, superiorly in the 
obtuse angle, formed between the projecting annulus and the 
stipe. If a small portion of the surface of this felted tissue 
be raised with a fine elastic needle, and placed in a drop of 
water, care being taken to avoid any strong pressure, whilst 
the point of the needle is moved about in the water until the 
particle is detached, it will be observed even under a mode- 
rate magnifying power, but very distinctly under one of 
363 diam., that the delicate filamentous cells of the structure 
are furnished with a vast number of gelatinous nodosities, or 
verrucosities, from which, occasionally, and frequently in 
numbers together, actively vibrating filaments project. They 
have the apparent length of 3 to 1 inch, and the thickness 
of a needle ; but more close investigation soon shows that 
they vary in length and thickness. The latter reaches, on the 
mean, 1-450th of a Paris line, varying from 1-800th to 
to 1-200th. The length is usually about 3-100ths, varying 
from 1-200th to 7-100ths. A gradual transition may be 
observed from this filament to immotile, discoid, minute 
elevations of the gelatinous matrix, and lastly, to simple, 
verrucose, nodular corpuscles. The movement of these 
vibratile filaments is very remarkable, and is especially well 
adapted for microscopical demonstration. It has the closest 
resemblance to that of the horns of the Snail, but is far more 
lively ; it resembles also, in some respects, the rowing motion 
of certain cilia, and the sweeping undulations of the Osez/la- 
tori@, or even an infundibuliform movement will be observed 
to predominate. Irritation of the filaments is succeeded by a 
violent convulsive movement, followed by a depression of the 


extremities ; sometimes by a spiral involution of the upper 
s 2 


244 HOFFMANN, ON CONTRACTILE TISSUES 


portion towards the lower; lastly, and most frequently, a 
rapid retraction of the filament into itself may be noticed, 
exactly as in the horns of the Snail. Spontaneous and perfect 
retraction, without any external cause, I have never observed. 
It is extremely rare that this movement alternates with a 
remission, or actual brief repose; it is independent of the 
time of day, or the age of the fungus; and it continues for a 
long time after the separation of the shred from the parent 
stem. If the preparation be placed in a little glass cell, 
closed so as to prevent evaporation, and brought under the 
microscope, distinct, though very faint, movements may be 
perceived, even at the end of 48 hours; ultimately, the 
substance is affected by the water in which it is macerated, 
the filaments shorten, and, at last, their remains, together with 
the gelatinous nodosities, appear to become distended into 
vesicles with large vacuities in the interior. 

The form of these vibratile filaments is usually perfectly 
cylindrical, and they frequently present, at the upper end, a 
minute head formed of the same substance as the filaments, 
that is to say, of a greenish, brilliant, highly-refractive mate- 
rial, without a trace of its being jointed, even under the 
highest magnifying power (680 diam.). In the more rare, 
thicker vibratile filaments, there may be perceived in the 
filamenf, a tubular cavity occupied by fluid, and presenting a 
faint rose colour ; this cavity is continued into the head, where 
it assumes the appearance of a sharply-defined vacuole, like a 
cell nucleus ; on rare occasions, this head is separated by con- 
striction, when it remains motionless, close to the filament. 
Although the head is usually formed by a manifest enlarge- 
ment of the extremity of the filament, I observed, on one. 
occasion, the following peculiar process. The end of the 
filaments became suddenly thickened in the upper fourth of its 
length, in such a way, that it presented the appearance of a 
thicker cylinder supported by a more slender inferior one ; 
the thicker portion quickly became divided in the interior, 
almost throughout the entire length; in the middle of this 
cleft, a minute quickly-growing globule suddenly appeared, 
whereupon the whole upper portion increased in width, 
becoming shorter at the same time, ultimately assumed a 
globular form, and presented a well-defined articulation with 
the slender stem, whilst the usual vacuole was developed in 
the interior. The head very often forms its vacuole quite 
independently, the stem remaining solid. 

These vibratile filaments, when the felted tissue is in the 
dry state, do not exist ready formed; they require, for their 
development, to be moistened either by rain, or purposely, and 


IN THE HYMENOMYCETES. 245 


it not unfrequently happens that they may be directly seen, 
under the microscope, to spring from a gelatinous nodule, 
scarcely a minute being requisite for the process. Inthe same 
space of time, one of these filaments will attain the length 
of 3-100 to; 6-100ths; it occasionally, also, happens that 
a lateral shoot is formed, which then continues to grow 
instead of the original principal axis of the disc or filament ; 
in this way is constituted an unequally bifurcate vibratile 
filament. 

The matrix, out of which the filaments are protruded, and 
into which they retract, invests the cells of the felted tissue, 
in the form of a gelatinous, nodular, faint-yellowish substance, 
sometimes presenting nearly isolated nodules, and closely 
adherent, but sometimes forming larger fragments, united, so 
as to constitute loosely-applied lobes, in the interior of which 
may be perceived larger and smaller vacuoles of variable 
forms, in great numbers. In making the preparation, it very 
rarely happens that a vibratile filament is wholly detached, 
but when isolated, it still exhibits movement. 

The most important circumstance characterizing the relation 
of these structures towards external influences, is the follow- 
ing; from which, also, the very necessary caution to be 
observed in the exposition of them is shown, 

Iodine colours them yellow, afterwards brownish ; sulphuric 
acid does not affect this colour, nor is any change observed 
when the reagents are employed in the reverse order; and 
particularly is no blue tinge observed, as is, by no means, 
unfrequently the case, otherwise with regard to the tissues of 
fungi: the application of syrup and sulphuric acid does not 
alter the colour. In both cases the application of the reagent 
is followed by the rapid death and collapse of the filaments, 
which are fused into a gelatinous mass, which gradually be- 
comes very transparent, and somewhat vesicularly distended ; 
some vacuoles, at the same time, appearing in the interior. 

Caustic potass produces a rapid contraction, and afterwards 
dissolves the filaments so that they become unrecognizable ; 
nothing remaining but a fluid abounding in granules. This 
is effected in a few minutes and without the aid of heat. 

Carbonate of potass induces lively extension, curvature, and 
contraction, succeeded by the formation of numerous nodules 
and yacuoles, the substance becoming perfectly clear as if 
solution had commenced ; at the same time several gelatinous 
nodules, in the form of drops or vesicles in which vacuoles 
may be distinguished, float on the fluid. 

Ammonia causes rapid contraction, without any immediate 
solution. 


246 HOFFMANN, ON CONTRACTILE TISSUES 


Common salt induces gradual contraction. When afterwards 
immersed in pure water for an hour, not a single filament 
could be seen protruded ; and even at the end of twenty-four 
hours only indistinct traces of them could be perceived. 

The electro-magnetic current, sufficiently powerful to decom- 
pose water, kept up for ten minutes, exhibited no definite and 
visible effect upon the filaments. 

Alcohol caused rapid contraction and hardening. 

Oxalic acid produced the same effect. 

Nitric acid caused rapid contraction, succeeded by a vesi- 
cular protrusion of the gelatinous nodules. When warmed 
for a short time the substance assumed a yellowish colour; it 
is consequently perhaps of an albuminous nature, 

Chloride of calcium: vapid contraction into nodules; this. 
agent consequently is not fitted for the preservation of such 
preparations ; for which purpose I do not know any general 
vehicle. 

In sulphuric ether the motion continues some time, but is 
ultimately succeeded by subsidence of the filaments and the 
subsequent formation of vacuoles. Nor does prolonged 
maceration in water again render the filaments apparent. 

Cherry-laurel water exerts little influence; whilst some of 
the filaments contract into little masses, the majority vibrate 
(undisturbedly) even after immersion for ten minutes. 

Syrup, added gradually, hinders the movement and causes. 
contraction, If the fragment be placed at once in concentrated 
syrup, not a single vibratile filament is apparent ; but if the 
preparation be afterwards placed in water, the filaments make 
their appearance in about ten or fifteen minutes; a fresh 
application of syrup induces renewed contraction. 

The filtered or unfiltered juice, expressed from the stipe of 
the fungus itself, destroys the motion and causes contraction ; 
but immersion of the preparation in water for half an hour 
restored the extension of the motile filaments. The reappli- 
cation of the juice of the fungus acted in the same way as 
before. Monades and other infusoria were not affected by it. 

The quality of the water, except as regards the accidental 
admixture of saline or pungent substances, is of no great con- 
sequence. Rain or spring-water act in the same way. The 
influence of temperature, however, is much more important. 
In a drop of water at the usual temperature (13° R.) the 
motion goes on actively, nor is it altered by the continued. 
addition of luke-warm water (20° R.); but when water 
warmed to 28° is added by drops it is immediately stopped, 
the filaments rapidly contracting on themselves. The addition 
of very cold water produces the same effect (+ 5°); but in 


IN THE HYMENOMYCETES. 247 


the latter case the contraction takes place but slowly, and an 
excellent opportunity is thus afforded for the study of the 
mode and nature of the contraction. If warm water (29°) be 
added every half minute, for about a quarter of an hour, and 
the preparation be then let alone, a few filaments make their 
appearance in about an hour, whilst the main bulk of the 
gelatinous nodules have become vesicularly distended, not 
unlike detached soap bubbles. If a preparation presenting 
this nodular condition be heated over the flame of a spirit- 
lamp till it boil, no change is apparent in it, and especially 
is there no protrusion of discs, filaments, or any other kind of 
elongations. 

Out of water and lying free in the air between plates of 
glass, no filaments are developed, nor can any indication of 
movement be perceived in the minute gelatinous nodosities. 

A moist atmosphere keeps the fungus for some time,— 
several days,—in the condition fitted for this investigation, 
on which account it is best preserved undera bell-glass; when 
exposed to the dry, warm air of a room, the felted substance is 
so closely matted that it is impossible to detach it from the 
point of the needle in the drop of water, without tearing it so 
much as to destroy it. 

Much pressure is especially prejudicial in this inquiry. 
The delicate filaments are thus reduced to a consistent mucus 
or fat, lose all form, and never regain any definite figure or 
vital activity; whilst the same degree of pressure has no 
injurious effect whatever upon any spores that may happen to 
be contiguous. 

The occurrence of these filaments is not limited to the 
situation above indicated. With patience they may also be 
found occasionally at the upper end of the stipe, as well as 
towards the border of the annulus (upper side); on one occa- 
sion I met with them on the free borders of the lamelle in the 
felt-like substance, which in the partially open fungus had 
previously separated the lamel/e contiguous to the stipe from 
its surface. I have noticed them in no other part of the 
fungus. 

I have repeatedly met with similar bodies in the corres- 
ponding situations, in Agaricus eburneus, Bull., and also in 
the widely-remote group of the Hygrophori, whilst I have in 
vain looked for them in the nearly allied A. phalloides, cam- 
pestris, fascicularis, lateritius, melleus, procerus, and Boletus 
granulatus. 

The consideration, especially of the situation of these 
structures, would naturally lead to the supposition that they 
may be connected with the process of fertilization. In fact, 


248. HOFFMANN, ON CONTRACTILE TISSUES 


at first, | thought I had at last discovered in them ‘ sterigmata’ 
and ‘ spermatia.’ The careful pondering upon the above- 
described relations, however, compelled me to abandon this 
notion. ; 

Another view had regard to the relation of these bodies to 
infusorial organisms. But the constancy of the occurrence, 
and that at all ages, even in fungi still completely closed, and 
in a perfectly recent condition, excluded the notion of their 
being parasitic, animal formations, to which their conditions 
of organization were also opposed. But, although from what 
appears, we are not justified at once in referring these struc- 
tures to the animal kingdom, this much is obvious, that we 
have to do with an organism, having much of the animal 
nature in it. 

This appears above all in the remarkable movement; but 
is also indicated in their physical and chemical properties. 
It seems to me indubitable, that we have here presented to’ 
us a contractile substance, identical with, or very closely 
allied to that, whose very extensive occurrence in the animal 
kingdom has been pointed out by Dujardin (Hist. Nat. des 
Zooph. ‘ Infusoires,’ 1841, p. 35), and termed by him ‘ sar- 
code,’ and which is also described by Ecker (Zeits. f. wiss. 
Zod. I., 218, 1849). This substance constitutes the bodies of 
the Infusoria, especially of those belonging to the polygastric 
class ; contractile drops, nodosities, filaments, and even root- 
like ramifications are frequently produced with great rapidity 
under the influence of water, especially if slight pressure be. 
employed ; this may be seen in the Rhizopoda, Hydraida, 
Polypes, &c. . 

Some time ago I left a number of. fresh specimens of Poly-' 
porus versicolor, covered, in a porcelain dish, and at the end. 
of several days found at the bottom of the vessel a few drops 
of a white fluid, which I submitted to the microscope.: 
Together with a great multitude of spores I noticed in this 
fluid a number of that remarkable, amorphous animalcule, 
termed by Muller Proteus, and by Ehrenberg Ameba (Amiba 
Gleichenii, Dujardin, Tab. 4, fig. 6), and which consists _ 
wholly of ‘ sarcode.’ I am therefore in a condition, from my 
own observations, to establish the similarity of the structures 
now in question, with respect to the physical conditions of 
their substance. 

The little masses of sarcode constituting the living tissue of 
the common Spongilla also presents scarcely any difference 
(Dujardin, |. c. Tab. 3, fig. 19). | 

This remarkable substance constitutes the entire body of 
the Huglene and of Hydra; in the Rotifera and Tardigrada, 


IN THE HYMENOMYCETES. 249 


it constitutes distinct organs corresponding to muscles; it 
forms the contractile, yolk-substance of the eggs of Limaz ; 
it occurs in the Trematoda, Cestoidea, the cystic worms, and 
in the Annelida; of it are composed the muscles of the 
young, just liberated insect-larve; and lastly, according to 
Dujardin (1. c. p. 40), it probably constitutes the substance 
between the skin and muscles of the fish, and, further modi- 
fied, the fibrous muscles of such peculiar morphological 
characters in the higher animals, In these lower structures, 
therefore, of the vegetable kingdom we may perceive the first 
distinct indication of an organ, which presenting a continually 
increasing development extends even up to man; a new link 
in the chain connecting the animal and vegetable kingdoms. 

It does not appear to me inadmissible to assume that the 
cilia of the spores of Alge present the closest analogy to our 
vibratile filaments; cilia are also known to be very widely 
distributed throughout the animal kingdom; and everywhere 
presenting lively movement without any articulation, an 
active molecular motion, as the innate property of the sub- 
stance. Moreover, I conceive there is no ground for sup- 
posing that motile phenomena of this kind, occurring so 
extensively, are to be explained by ‘ endosmosis,’ which would, 
in fact, be an attempt to elucidate one fundamental pheno- 
menon by another, and to get lost ina maze of hypotheses. 

The similarity of these filaments with certain alge is more 
apparent than real, and disappears when they are more atten- 
tively considered. -The most obvious comparison is with 
Oscillatoria, the refractive property of which is almost the 
same, and even whose colour is frequently identical. [The 
author then proceeds to describe the effect of certain chemical 
reagents upon Oscillaria limosa and Phormidium vulgare, 
from which he concludes that neither of those plants contains 
sarcode, or at all events presents a substance only distantly 
related to that principle. | 

But the sarcode appears to me to be very closely allied, if 
not identical, with the ‘ primordial sac,’ a conclusion to which 
Cohn (Hematococcus) was also led, although in a different 
way. I am led to make this assertion by the relations of the 
primordial sac in the conjugated cells of Spirogyra, as well as 
during the development of the spore-sac, as I have observed 
in Peziza vesiculosa, Bulgaria inquinans, in the process of 
growth of several Agaric spores, and in the germination of 
Uredo and Fusarium. 

I cannot here refrain from broaching a supposition, relative 
to the motile phenomena of higher plants. My observations 
(Unters. iib. den Pflanzenschlaf; Giessen, 1851) show in the 


250 DR. BRAUN, ON THE DISEASES OF PLANTS. 


most indisputable manner that in these remarkable phenomena 
there may be witnessed fatigue, torpor, and recovery by rest, 
precisely as we are accustomed to observe under similar cir- 
cumstances in animals. Fée (Mimosa pudica, in Mém. de la 
Soc. d’Hist. Nat. de Strasbourg, t. iv., 1849,) from similar 
observations has been induced at once to affirm, that with our 
present knowledge of this process, it is impossible not to 
assume the existence of a contractile substance in Mimosa 
pudica. 1 believe that this opinion is in some degree sup- 
ported by the observations communicated above, but I must 
also add that I have not succeeded in actually finding in the 
struma of the leaves in the sensitive plant, a substance similar 
to. that which occurs in the fungi above enumerated, even 
under the application of the best reagents. It is true, the 
specimen upon which I experimented, it being late in the 
year, was nearly dead, and presented even upon violent agita- 
tion only very faint movements. It is possible the result 
might be different in the warm summer season. 

[The author’s argument with respect to the identity, at any 
rate in some respects of the motile substance in the animal 
and vegetable kingdom, is strongly supported by the effects 
of the vapour of chloroform, which appear to be exactly 
similar in both cases. This effect may be readily witnessed 
if a bunch of blossoms of the common Barberry be exposed 
for a very short time to the vapour of chloroform. The iri- 
tability of the filaments is annihilated, and if the exposure 
have not been too prolonged returns after a certain interval. 
We have been informed that a similar influence is exerted 
upon the motions of the ‘sensitive plant.’ Experiments to 
the same effect upon the cyclosis in Valisneria, &c., would be 
of interest. The effects of chloroform upon the motile element 
throughout the animal kingdom, from the highest to the 
lowest members, are precisely alike. } 


On some new or little-known Diseases of Piants, caused by 
Funer. By Dr. Avex, Braun. With Appendices, by 
Dr. Caspary and Dr, Anron pe Bary. Berlin, 1854, 

pp. 33, and 2 Plates, 


In the introductory part of this brochure, Dr. A. Braun says 
that, “ As the history of the civilization of the human race 
has its dark side in the development of many obstinate social 
evils which accompany the march of advancing civilization, 
so also has horticulture and agriculture, together with the 
bright, their dark side. There are certain diseases to which 


DR. BRAUN, ON THE DISEASES OF PLANTS. 251 


plants, in the state of cultivation, show themselves to-be more 
obnoxious than when they are in their natural localities, and 
subject to the original conditions requisite for their flourishing. 
That this dark side fully deserves the attention of the gardener 
and of the farmer, is obvious, from the incalculable evils that 
ensue upon the mysterious and unexpected appearance of one 
of these vegetable plagues. The more difficult it appears to 
investigate the causes of these diseases, and to discover 
means by which they may be arrested or prevented, so much 
the more are they worthy of profound study.” 

With these observations every one must agree, and we feel 
it needless to insist upon the utility of attention to this subject 
by those whose opportunities and scientific acquirements may 
render them competent to employ the microscope in researches 
demanding no less a clear and scrutinizing vision than an 
unprejudiced and clear-seeing mind, Many diseases of plants, 
so important in their injurious effects upon some of the most 
valuable of Nature’s offerings to the use or enjoyment of 
mankind, such as the potato and the vine, appear to be, 
especially, subjects of microscopical research, “‘ since, in most 
cases, the presence of a parasitic organism, a fungoid growth 
will be found to be the cause of the disease.’ And these 
organisms are all of microscopic size. 

In cases where the diseases of plants have occurred in con- 
nexion with fungoid growths, the question whether the disease 
has produced the fungus or the fungus the disease, has been 
answered in various ways. The view which was earliest 
entertained, viz., that the fungus was developed simply asa 
product of the morbid process by spontaneous generation 
from the diseased parts of the plant, has, at present, but few 
supporters ; it is opposed to the positive observations that 
have been made respecting the germinating power of the 
spores of these parasites, as well as with respect to their per- 
sistent vitality, inasmuch as it has been proved by experiment 
(in the spores of Botrytis bassiana), that they will retain their 
vitality, in the dry state, for years together. But since the 
development of the fungus cannot be regarded as the direct 
product of the disease, the next thing is to inquire whether it 
has any dependent relation to the disease in another way. It 
has been assumed that the appearance of the fungus is always 
preceded by a morbid affection of the plant or of its parts, by 
which a fitting soil was provided for the growth of the fungus ; 
and it cannot be denied that there are a vast number of fungi 
growing either upon plants entirely dead, or upon parts of 
them in a state of disease, as well as upon animal substances, 
and which, consequently, are not to be regarded as the cause 


252 DR. BRAUN, ON THE DISEASES OF PLANTS. 


of the disease, or of the death, but as accidental concomitants 
or followers of it. Thus, for instance, in potatoes rotten in 
consequence of the potato-disease, numerous forms of fungi 
grow, of which more than a dozen are known, but to none of 
which can the potato-disease be attributed. 

It is equally certain, however, that even the sound organisms 
of plants and animals may be attacked by parasites from both 
kingdoms, whose presence is followed sometimes only by 
local morbid processes and manifold malformations, but 
sometimes, also, by general disease and death. To parasites 
from the animal kingdom it is needless here to advert ; and 
with respect to parasitic plants, it may be remarked that some 
belong to the higher orders of the vegetable kingdom, as, for 
instance, the various species of Orobanche, the misletoe, Cus- 
cuta, §c.; but the majority of the parasites belonging to this 
kingdom, exist in the multitudinous class of fungi. Of 
plants of this kind, infesting living animals, Robin (Hist. 
Nat. de Végétaux parasites qui croissent sur homme, et les 
animaux vivants) enumerates not less than 86 species. To 
the fungi which vegetate upon living plants, belong, in the 
first place, the whole host of ‘rust’ and ‘smut’ fungi 
(Uredo, Puccinia, Phragmidium, dicidium, and the allied 
genera) which, as ‘entophytes,’ are developed in the interior 
of the tissues; to these, moreover, belongs the well-known 
“ergot,” whose previously enigmatical nature has lately been 
cleared up by M. Tulasne ; who, by a lengthened series of the 
most profound observations, has shown that the body of the 
ergot, which is, externally, of a blackish colour, and internally 
white, and which has been described as Sclerotium clavus, is 
only the vegetative rudiment of a claviform fungus, which is 
not developed until it has fallen to the earth. This fungus is 
very closely allied to the Spherie growing upon caterpillars, 
and is described by M. Tulasne under the name of Claviceps 
purpurea. ‘The destructive fungus of the vine-disease, the 
so-termed Oidium tuckheri, is certainly nothing else than a kind 
of mildew ; and in the instance of this fungus, it has been 
placed beyond all doubt by numerous researches, and par- 
ticularly by those of Mohl, that it originates in perfectly sound 
parts of the vine, the disease and death of the cuticle, with 
their injurious consequences upon the ripening of the fruit, 
not commencing till after the fungus has made its appearance. 
The infection of the potato-plant by the Botrytis (Peronos- 
toma) infestans, has the greatest analogy with the vine-disease ; 
the brown spots are the invariable sequel of the appearance 
of this fungus. So soon as these spots are perceived, the 
delicate fungoid growth must be sought for around their 


DR. BRAUN, ON THE DISEASES OF PLANTS. 253 


margins, as it rapidly disappears from the centre of them. 
The circumstance that the brown spots remain, although the 
vegetation of the Botrytis subsequently disappears, or is, 
occasionally, so interrupted that its presence is not readily to 
be detected, has given rise to the erroneous views with respect 
to the primary origin of the brown spots. 

The morbid phenomena produced by fungi are either local 
or, as it may be termed, general. The former is the case with 
most of the fungi known under the name of ‘rust,’ when they 
do not exist in too great quantity, such as Trichobasis (for- 
merly Uredo), Rubigo vera, and lineeris, Puccinia, Cystopus, 
§c. These genera, however, and others, which, when existing 
in small quantities, have merely a local effect, when more 
extensively developed may exert a pernicious influence upon 
the entire organism of the plant or tree, by causing the falling 
off of the leaves, &c. This local influence, however, when it 
affects the blossom or its essential parts, will, of course, be 
followed by sterility ; and in this situation the attacks of the 
parasite are often indicated by monstrosities in the flower or 
its parts; sometimes, again, sterility is caused by the effect 
of the fungus being shown in the prevention of the formation 
of the blossom, as in the case of Euphorbia cyparissias when 
attacked by Aicidium Euphorbia, or even by Puccinia Euphorbia, 
whilst Uredo Euphorbia, on the other hand, induces neither 
sterility nor any other striking change in the plant. 

When the array of diseases produced by fungi, which, for- 
merly unnoticed, have, in later times, attracted universal 
attention by their destructive consequences, is surveyed, it 
might readily be supposed that, as in the diseases to which 
the human frame is subject, every period has its prevailing 
character, so, also, in the vegetable kingdom, certain variable 
and secular influences prevail, to which is to be ascribed the 
circumstance of the present activity of diseases produced by 
fungi. At any rate, it appears that the meteorological con- 
ditions in the last few years have not been so unusual that a 
sufficient explanation of the destructive outbreak of these 
diseases is to be sought for in them. Besides the formidable 
potato-disease, numerous other diseases belonging to the same 
category have, of late years, invaded the vegetable kingdom, 
among which is to be enumerated, as of the greatest impor- 
tance, the vine-disease, whose increasing extent may be traced 
from year to year. In 1852, the mulberry trees in Italy were 
attacked by a disease previously unobserved, the cause of 
which was discovered by Montagne in a fungus which invades 
the leaves, and is described by him under the name of Fusis- 
porium cingulatum. In 1851, a disease very destructive to 


254 VIRCHOW, ON CHROMATOPHORES IN THE FROG. 


the orange trees, was described by Rendu, as caused by the 
attack of a fungus upon the roots, a species of Rhizoctonium. 
In the summer of 1851, the different species of Azbes, in the 
neighbourhood of Bercelli,in Piedmont, were invaded by a 
fungus named Nematogonium byssinum, and whose effects 
were very fatal to the plants. Diseases in a similar way, 
produced by fungi, and invading the cultivated Parsnip, and 
also observed upon Pimpinella saxifraga, and upon Anthriscus: 
sylvestris and Angelica sylvestris, have been described. The 
author concludes by describing and figuring several new 
species of fungus, one of which attacks the species of Robinia, 
—Septosporium curvatum ; another, Acrosporium cerasi, invading 
the Cherry ; Hemphylium ericoctonum, a disease of the species 
of Erica; and Hetrochete malvarum, one affecting the mallow 
tribe. 


On CuromaTopuoreEs 2n the Froc. By R. Vircuow. Ab- 
stracted from the ‘ Archiv. f, path. Anat. u. Physiol., &e. 
Vol. vi., part 2, pp. 266. 


Axmann (‘Beitragen z. mikrosk, Anat. u. Physiol. des Gan- 
glien-Nerven Systems.’ Berlin. 1853.) has communicated 
the results of a series of transverse sections of the nerves, 
which would appear to establish the important fact, that the 
sympathetic nerves regulate the circulation, whilst nutrition. 
is under the influence of the ganglio-spinal nerves. With 
respect to the latter point especially, he has adduced the 
remarkable fact, that when the ganglio-spinal nerves in the 
Frog are cut across, the well-known stelliform pigment-cells 
are said to lose their rays, and to become atrophied. 

The importance of these representations seemed to make it 
desirable that they should be subjected to farther inquiry ; and 
tle more so, since Valentin had already adduced many con-' 
siderations opposed to some previous statements to the same 
effect, brought forward by Axmann. 

H. Meyer (of Oldenburg) undertook this inquiry, and will. 
at a future time himself report the results at which he may 
arrive. But it appears at present desirable to make a few 
observations with respect to the pigment-cells. 

It is a fact, that after division of the ganglio-spinal nerves 
going to the foot, in a frog, the pigment was rendered pale, 
a change which was manifest even to the naked eye; and, as 
we were examining the web under the microscope, the radiat- 
ing processes, as Axmann describes, actually disappeared. 
But the comparison of both extremities very soon showed 
that, in proportion as the processes became invisible, the. 


SIEBOLD, ON CYSTICERCUS PISIFORMIS. 255 


centre of the pigment-cells, their proper body, increased in 
size, so that it was evident that the pigment was collected 
from the processes or prolongations into the body of the cell. 

Consequently the same change takes place in the pigment- 
cells of the Frog, as occurs in the Chromatophores of the 
Chameleon and Cephalopoda, with which we have been made 
acquainted by the researches of Briicke. The change of 
colour depends upon the alteration in form of the pigment- 
cells, and the change in place of the pigment itself, so that, in 
fact, the colour of the Frog appears to be the darker, the more 
the pigment is poured into the processes, and the brighter, the 
more it is collected into separate aggregations in the interior 
of the cell-body. The phenomenon, therefore, presented in 
this case, is manifestly not one simply of nutrition, but of 
contraction. 

Harless (Miinch. gelerhte Anzeigen, 1853; No. 35, p. 286) 
would appear to have observed the same phenomenon in the 
nictitating membrane of the common Frog, and throughout 
the integument of the Tree-Frog. He describes a varying 
distribution, in consequence of a change in the dimensions of 
certain pigment-cells, of a stratum of apparently viscid fluid 
between the clear, slightly brown-coloured granules of stelli- 
form or irregularly-formed cells with elastic walls, the colour, 
as in the soap-bubble, depending upon the thickness of the 
fluid film. The passage is the less clear to me, because 
Harless speaks, besides this, of an unchangeable, gold-yellow 
colouring matter contained in other cells, and of the colouring 
matter of the black pigment-cells. In the natatory membrane 
of the Frog, however, it is precisely the latter upon which the 
change of colour depends. 


On the Transformation of Cysticercus Pistrormis into Txnif 
-serRATA. ByC. Tu. v. Srepotp. From the Zeitsh f. Wiss, 
Zoologie, B. 1V., pp. 400. 


In the year 1844 I first drew attention to the similarity be- 
tween the head-end of Cysticercus fasciolaris of the rat and 
mouse and Tenia crassicollis of the cat, and to the mutual re- 
lations of these two parasitic forms, on which occasion | 
broached the assertion that the Cysticercus fasciolaris is an 
aberrant and degenerated Tenia, but one still capable of 
attaining the normal form of a tapeworm, when it is transplanted 
into the intestinal canal of a suitable animal. In this case 
the short joints of the C. fasciolaris are completely formed, 


y 


and the generative organs which are wanting in this Cyst?- 


256 SIEBOLD, ON CYSTICERCUS PISIFORMIS. 


cercus as in all the cystic Entozoa arrive at their due deve- 
lopment. At the same time I pointed out the way in which 
this transformation of the asexual C. fasciolaris into a fertile 
Tenia crassicollis might be traced, showing that when mice 
and rats, whose livers are infested with this cyst-worm, are 
devoured by cats, the latter would digest in their stomachs 
the livers of the rodents swallowed by them, but not the C. 
fasciolaris contained in the livers. This entozoon, on the 
contrary, feeling itself transplanted into a proper soil, throws 
off the dropsical degenerated joints in the digestive canal of 
the cat, and acquires the form of J. crassicollis, and arrives at 
sexual maturity. Allan Thompson, of Glasgow, without, 
as it seems, his being acquainted with my researches and 
published observations on this subject, had recognized the 
correspondence of C. fasciolaris with T. crassicollis. Pursuing 
the subject farther I finally became convinced that all cystic 
Entozoa are nothing else than undeveloped or larval tape- 
worms, which, arrested in their wanderings, have become 
aberrant and dropsically degenerated. I presented it to the 
helminthologists as a problem, to determine what completely 
developed and sexual species of cestoid worms belonged to 
each degenerated and asexual cystic form, warning them, how- 
ever, against over hasty conclusions and deceptive appear- 
ances, which so readily arise in inquiries of such a difficult 
nature.* ; 

Dr. Kiichenmeister, of Zittau, has devoted himself, during 
the past year, with the most untiring zeal to these difficult re- 
searches. But owing, perhaps, to this extreme zeal Kiichen- 
meister was induced to publish his researches and experi- 
ments before they could be regarded as completed. He first 
stated that from 40 individuals of Cysticercus pisiformis of the 
rabbit he had succeeded in producing 35 specimens of Tenia 
crassiceps of the fox, and indeed Tenia, in 22, 15, 8 days, and 
30 hours.t| Some weeks afterwards he correctedt{ this preli- 
minary communication, stating that he had been wrong in 
regarding the tapeworm produced in his experiments from 
the Cysticercus pisiformis as Tenia crassiceps, having learned 
from Dr. Creplin that it was the J. serrata of the dog. Dr. Kii- 
chenmeister also sent to me for determination various Tenie, 
produced by him from Cysticercus pisiformis; but as these 
specimens were not sexually developed, and the ova, which 
afford such excellent specific characters in the Tenia, were 
wanting in them, I did not venture to give a definite judgment 

* Zeitsh. f. w. Zool. 1850, p. 201. 


+ V. Giinsburg’s Zeits. f. Klinische Vortrige, 1850, p. 240. 
t Ib. p. 295. 


SIEBOLD, ON CYSTICERCUS PISIFORMIS. 257 


as to the species of these Tenia, and was inclined, until I should 
receive from Dr. Kiichenmeister some sexually mature speci- 
mens of the species, to regard those transmitted by him as a dis- 
tinct species. Dr. Kiichenmeister consequently was induced 
to abandon Dr. Creplin’s determination of the tapeworm pro- 
duced from Cysticercus pisiformis,* and to regard it as a new 
species, under the name of T. pisiformis. This rapid suc- 
cession of contradictory statements would naturally have the 
effect of disinclining the medical public to believe in the 
possibility of the transformation of the Cysticercus into a 
Tenie. But even with helminthologists themselves Kii- 
chenmeister’s statements could not meet with any real accept- 
ance, as it was but too apparent from the whole exposition of 
his researches, that he was still, as he himself confesses, defi- 
cient in helminthological information. 

A prime error, into which Dr. Kuchenmeister fell, consisted 
in this, that when, in a Cysticercus which had been swallowed, 
and examined in the intestines of a dog, he found the usually 
retracted head and neck protruded, he at once explains this 
condition as the already commenced transformation of the 
Cysticercus into a Tenia. It is in this way that in his expe- 
riments he must have arrived at this very remarkable and, to 
helminthologists, incredible result, which he describes when 
he states that the cystic worms swallowed by one dog were 
transformed into Tenie in five, and in another after three 
hours. If Dr. Kiichenmeister imagines that a Cysticercus, 
which, after it has passed into the intestinal canal of a dog, 
has lost its caudal vesicle and protruded its neck and head, has 
already undergone a transformation into a Tenia, it may be 
stated that a similar transformation may be very simply 
effected spontaneously when a C. pisiformis is put into luke- 
warm water and time allowed for it to protrude its head and 
neck, when a snip with a pair of scissors will at once com- 
plete the metamorphosis into a Tenia. All the Tenie 
figured by Kiichenmeister, and which he states himself to 
have obtained by his “ feeding”’ experiments, are also nothing 
more than a caudal and extended Cysticercus. Statements of 
this sort appearing to me likely to throw discredit upon the 
account I had given of the metamorphosis of the cystic worms, 
I determined to undertake myself the researches and experi- 
ments demanded in the investigation of this perplexed in- 
quiry. I commenced in the March of the present year with 
Cysticercus pisiformis, with which Kiichenmeister had already 
instituted six “ feeding” experiments. Dr. Lewald, one of 


* ©Ueber Finnen und Bandwiirmer;’ in the Vierteljahrs f. prakt. 
Heilk. Prag. 1852. Bd.i., p. 150. 
VOL. II. 43 


258 SIEBOLD, ON CYSTICERCUS PISIFORMIS. 


my most zealous pupils, aided me in this, with the intention 
also of making these researches the theme of his Inaugural 
Dissertation. This has just made its appearance,* accompa- 
nied with a plate of figures, exhibiting the gradual transforma- 
tion of Cysticercus pisiformis into Tenia serrata, as presented 
in the intestinal canal of ten dogs fed with these cystic 
worms, and which were killed at the most various periods, 
viz., from 2? of an hour up to 65 days after the feeding had 
taken place. : 

In the first place, three rabbits and two guinea-pigs were 
fed with the cyst-worms. ‘These experiments afforded no re- 
sult whatever ; for several days afterwards, upon opening these 
rodents, the cyst-worms were never to be found in the diges- 
tive canal. The happiest results were -arrived at in “ feed- 
ing” experiments made with young dogs. For a full detail 
of these experiments and their special results I must refer to 
Dr. Lewald’s Dissertation, here merely noticing, in general, 
the destiny and vital condition which the cyst-worms under- 
went in the digestive canal of the dogs. Remarking at the 
same time that the cyst-worms used by us were always re- 
tained in the peritoneal cysts, in which they had been found 
in the omentum of the rabbits. 

The first effect produced upon the Lntozoa thus enclosed in 
their cysts, after they had been swallowed, was the solution of 
the cysts by the gastric juice in the dog’s stomach, whereupon 
the caudal vesicle was attacked and destroyed by the same 
digestive agent; so that, of the whole Cysticercus pisiformis 
nothing was left but the whitish and rounded body which had 
been concealed in the caudal vesicle, consisting of the head 
and neck of the creature invaginated in the body. The 
caudal vesicle, before its digestion, was frequently shrivelled 
and collapsed, probably because the thin fluid contents were 
excreted by exosmosis into the more dense pultaceous con- 
tents of the stomach. At the same time the remains of the 
cyst-worms, that is to say, the tailless bodies with the inva- 
ginated head and neck, pass through the pylorus into the 
duodenum. Arrived there, the head and neck are protruded 
from the body of the entozoon, for the purpose of seeking a 
spot of adhesion between the villi, in which situation it has 
to await its subsequent growth and the further completion of 
its body. In the first hours of their abode in the small in- 
testine, these extended tailless Hntozoa often continue to pre- 
sent a bloated, oedematous aspect; but gradually the body 

* De Cysticercorum in Tznias Metamorphosi pascendi Experimentis, in 


Instituto Physiologico Vratislaviensi administratis illustrata. Auctor G. 
Lewald. Berolini, 1852. 


SIEBOLD, ON CYSTICERCUS PISIFORMIS. 259 


becomes more slender, probably from its giving off the super- 
fluous fluid by evosmosis, and thus the Entozoa acquire pretty 
nearly the same specific gravity as the more or less dense 
chyle. At the posterior end of all these extended tailless 
cyst-worms, the point at which the caudal vesicle was pre- 
viously attached is distinctly indicated by a sort of cicatrix, 
in the form of a notch or excavation, from which, at first, 
very delicate membranous flocculi, the remains of the de- 
stroyed caudal vesicle, are seen to depend. In a few days the 
growth of the Entozoa commences, in which the body alone 
participates, the head and neck having attained their full 
development and perfection, whilst the creature was still re- 
sident in the peritoneum of the rabbit. As the body, which 
is still altogether unjointed and furnished only with closely- 
approximated transverse wrinkles, continues to increase in 
length, its transverse wrinkles are multiplied ; and the growth 
of the body being continued uninterruptedly, are, in the course 
of a few days, formed into distinct joints or segments. The 
joints, which are at first very short, elongate, and soon present, 
sometimes upon one sometimes upon the ee lateral margin, 
a papillary elevation, which is afterwards developed into the 
aperture of the generative organs. In this condition the cyst- 
worms completely resemble a Tenia, and betray their origin 
only in the cicatrix, which still exists on the last joint of the 
body. After a residence of 25 days of these worms in the 
intestine of a dog, they have attained a length of from 10 to 
12 inches. The growth of these Yenie continues uninter- 
ruptedly, in the course of which their posterior joints increase 
in breadth, and the generative organs in their interior ap- 
proach more and more nearly to their full development, whilst 
behind the neck the formation of continually new joints pro- 
ceeds out of the transversely wrinkled anterior portion of the 
body. In three months these Tenie have attained a length 
of from 20 to 30 inches or more, and in them the posterior 
joints appear to be sexually quite matured. In some of them 
the last joints are now also detached—an additional proof of 
their sexual maturity. The ova contained in the ripe joints 
are seen to be completely developed, and containing in their 
interior the mobile embryo armed, in the way well known, with 
six hooklets. 

This stage of development of the tapeworm, which is pro- 
duced from Cysticercus pisiformis, enabled me to determine its 
species with certainty, and I satisfied myself that it belonged 
to Tenia serrata. The form of the head, the number, shape, 
and arrangement of the hooklets on the head ; the conforma- 
tion of the joints, and of the sexual organs contained in them ; 


tr 2 


260 SIEBOLD, ON CYSTICERCUS PISIFORMIS. 


all proved to me that I had 


the figure of the mature ova 
before me Tenia serrata. 

It should be mentioned, that on the dissection and exami- 
nation of the intestines of the dogs thus fed with Cysticerct 
some individuals of Ascaris marginata, and several sometimes 
longer, sometimes shorter, individuals of Tenia cucumerina 
were always met with. Although, from the above-mentioned 
experiments and the results obtained from them, I am now 
myself almost convinced that the Cysticercus pisiformis 1s 
transformed in the digestive canal of the dog into Tenia 
serrata, | am not sure that even these experiments will carry 
the same conviction to other zoologists and helminthologists. 
Shall I not have opposed to me this question: how, from my 
experiments, can I be certain that there were no Tenia serrata 
in the intestine of the dogs before they were fed with the 
Cysticerci? For there would be no more difficulty in those 
entozoa finding their way, in another mode, into the dog than 
in Ascaris marginata and Tenia cucumerina doing so. With 
respect to which I must remark, that in my experiments I 
made use only of parlour or house dogs, and Tenia serrata, 
according to my experience, very rarely occurs in domestic 
dogs of that kind, whilst it is much more abundant in hounds. 
I have examined the intestines of many domestic dogs which 
had not been fed with Cysticerci, and scarcely ever met with 
a Tenia serrata in them, but, on the other hand, Tenia 
cucumerina almost always occurred. I would, moreover, 
remark, that after a “ feeding” with Cysticercus pisiformis the 
number of tapeworms found in the dog’s intestine, and more 
or less developed into Tenia serrata, always corresponded 
with the number of the Cysticerci which had been adminis- 
tered in each experiment. Another very noticeable circum- 
stance is this, that the size and stage of development of the 
individuals of 7. serrata found in the intestine of the dog fed 
with the cyst-worm always precisely accorded with the time 
which had elapsed since the “ feeding.” 

Important as this demonstration of the transformation of 
Cysticercus pisiformis into T. serrata is with respect to the 
natural history of the Cestoidea, care must be taken not to 
apply too much of what we learn from the history of this one 
tapeworm to all others of the same class. Kiichenmeister 
seems to have concluded that all the other Teni@ are also 
derived from cyst-worms, which must be altogether denied ; 
for were all Teenie obliged to pass from the condition of an 
embryo furnished with six hooklets, first into a sexual Cysti- 
cercus armed with a coronet of hooks, before it could be deve- 
loped into a perfect, jointed, and sexual individual, we should 


SIEBOLD, ON CYSTICERCUS PISIFORMIS. 261 


certainly be acquainted with a much greater number of cystic 
forms than have hitherto been made known. According to 
the most recent enumerations the number of known Teenie 
includes about 188 different specific forms, whilst of the genus 
Cysticercus scarcely 16 defined species can be adduced, and 
our knowledge of all the genera of cystic worms in general 
does not embrace 25 species altogether. As cyst-worms, as 
is well known, occur only in animals, and thus can only be 
introduced by the feeding upon flesh, it can hardly be ex- 
plained, on the supposition that all Tinie proceed from them, 
in what way the Teenie of the herbivorous mammalia can 
have been introduced as cyst-worms into the intestine of the 
animals infested by them. That all Tenie have not previ- 
ously been cyst-worms is shown in the development of a 
tapeworm observed by Stein.* His observations distinctly 
indicate that the embryo with six hooklets which escapes from 
the tapeworm egg is not immediately transformed intoa Tenia 
or cyst-worm, but that, in the first place, a young tape- 
worm is developed in the interior of this embryo in the form 
of the head-end of a Tenia (Scolex-form). Such a Tenia, 
were the posterior end of its body expanded into a vesicular 
form and filled with a serous fluid, would completely resemble 
a Cysticercus. Under what circumstances such a degeneration 
in Tenia, as yet asexual, comes to pass, is, it must be con- 
fessed, as yet unknown. 

Very recently objections have been raised to my statement, 
that cyst-worms are morbidly degenerated tapeworms. K tichen- 
meister has propounded, in opposition to me, the notion that 
the caudal vesicle of the Cysticercus is a necessary organ in 
the cystic state of the entozoa, assigning it the function of a 
nutritive reservoir. How far this assertion is correct, or the 
reverse, must be left to special researches in the subject to 
decide. At the same time I am quite ready partially to 
modify my definition of the cystic condition, and, though 
willing to abandon the term ‘“ morbid,” must, on the other 
hand, the more firmly retain the designation ‘“ degenerated ” 
(entartet), as my latest researches have more and more tended 
to convince me that the cystic worms are really degenerated 
tapeworms, and that the form and size of the caudal vesicle do 
not depend upon the specific form of the Cysticercus, but 
upon external, adventitious, accessory influences. I must 
confess that I cannot rightly perceive upon what grounds 
endeayours are made to show the possibility of varieties in 
form and figure in the worms, since, in the higher animals, the 
deviations from the normal type induced by climate, condi- 


* Zeitschrift f. w. Zool. iv. bd, 1852, p. 205. 


262 SIEBOLD, ON CYSTICERCUS PISIFORMIS. 


tions, and altered nutriment are admitted without dispute. 
That these varieties occur according to certain laws, and 
always return to a definite form, is shown in the different 
“ races” of domesticated animals. When, in many of these 
races, an excessive secretion of horn-substance takes place in 
the growth of hair, in others an unusual deposition of fat, why, 
in certain lower animals, should not an accumulation of serous 
fluid, or dropsy, take place, when they have deviated from 
their usual mode of life? 

It must now be an important task for helminthologists to 
trace the further development of the embryos which proceed 
from the ova of Tenia serrata, in order that they may deter- 
mine in what way the Cysticercus pisiformis is produced from 
them. 

To those who wish to repeat the “ feeding” experiments 
with Cysticercus pisiformis, in order to obtain from it the 
Tenia serrata, and who, for the more sure determination of 
the Tenia thus obtained, are desirous of consulting figures, I 
would remark, that numerous errors have crept into the various 
helminthological papers under the head of Tenia serrata, 
which have up to the present day remained unnoticed, and 
which have been caused by the circumstance that formerly 
Tenia serrata and Terassicollis could not be suitably distin- 
guished. Both species of tapeworm, although in the confor- 
mation of the joints closely allied, are easily recognizable by 
the head. TF. crassicollis has a very strong and broad rostrum, 
almost as wide as the head. Its short neck is continued with- 
out any contraction uniformly into the jomted body. In 
T. serrata the rostrum with its coronet of hooks is much nar- 
rower than the head, its somewhat longer neck is always con- 
tracted behind the head. ‘This distinction is very apparent 
in every figure which Goeze has given of T. crassicollis and 
serrata; but, notwithstanding this, Goeze appears to have 
Gaeaered Sorihasion gaits saatieds because various specimens 
Mich ple nas figured as TJ. serrata according to him are 
said to have been procured from the intestine of the cat. 
Whether Goeze in this statement has made a mistake, or 
whether J. serrata may not also occur in the intestinal canal 
of the cat, 1am not at this moment in a condition to decide. 
In any case the following figures in Goeze refer to T. serrata: 
Tab. XXV. A, figs. 1— “5; Tab. XXV. B, figs. A—D ; and 
Tab. XXVI., fas 1—4., The last-memaie plate is incor- 
rectly cited by Rudolphi * as referring to T. erassicollis ; and 
subsequently this extremely good figure of J. serrata has been 
altogether lost sight of, and never cited by later helmintholo- 


* Entozoor. Hist. Naturalis. Vol. ii. p. 2, 1810, p. 174. 


BLACK FUR ON THE TONGUE. 263 


gists ; whilst Goeze’s figure of Tenia serrata, in Tab. XX. A, 
figs. 1—5, is erroneously assigned by Diesing* to T. crassi- 
collis. Besides Goeze’s figures of T. serrata I would notice 
Gurlt’s T representation of this cestoid-entozoon. 


On a “ Buiack Fur on the Toneur.” By Dr. Eutensere, of 
Coblenz. Abstracted from the ‘ Arch. f. Physiol. Heilk.,’ 
August, 1853. 


Tue author relates that in the preceding year a child, two 
years old, was brought to him whose tongue was covered with 
a perfectly black coating. The organ, from the tip to the 
back, appeared as if it were smeared with ink; and at first 
sight the supposition necessarily entertained was, that the 
child had licked some black object, or had swallowed a 
coloured liquid. Except a slight diarrhcea, the boy presented 
no other morbid symptoms. For his age, he was well deve- 
loped, and had never had any important illness. The author’s 
immediate treatment was confined to washing the tongue with 
vinegar and water. 

Fourteen days afterwards, the child was again brought to 
him, when the mother stated that the washing of the tongue 
had removed the black colour only for a short time, at most 
for not more than a day, when it returned with the same inten- 
sity as at first. Dr. Eulenberg prescribed some indifferent 
medicines, in order to keep the child under observation ; 
directing the continued use of vinegar and water as an 
external application. But, notwithstanding the diarrheea had 
long ceased, the tongue remained the same for three months. 
When the organ was cleansed, the black colour reappeared, 
first in the middle and anterior half, afterwards gradually 
covering the entire dorsum of the tongue, and extending as far 
as could be seen. The lingual papille were, at the same time, 
much developed. The papille filiformes were very distinct, 
and were especially dark-coloured. The papille vallate, pro- 
jecting in a conical form, presented, particularly at their 
apices, a deep-black covering. Even after the tongue was 
washed these papille retained the colour, and were merely 
surrounded by a pale border, owing to which the black hue of 
the apex was rendered the more striking. If the coloured 
tongue was scraped, a viscid brownish mucus was obtained, 
which, under the microscope, exhibited a large quantity of 
thickened epithelial cells and granular pigment. 

* Diesing. Systema Helminthun. Vol. i. 1850, p. 519. 


+ Gurlt. Lehrb. d. Patholog. Anatomie der Haussaugethiere. Th. i. 
1851. Tab. ix. fig. 9-10. 


264 DR. EULENBERG, ON 


If the mucus thus scraped off were dried upon paper, there 
remained extremely delicate black or dark-brown filaments, 
about as thick as a fine hair, and from } to 4’” in length, or 
minute irregular plates of the same length and breadth, If 
the latter were divided, they frequently afforded minute, crisped 
particles, like fine down. Particles of the same kind, however, 
were often met with independently. Their elasticity was 
evidenced in this, that they often sprung away when an 
attempt was made further to subdivide them with needles. 

Under the microscope they represented distinct, very much 
thickened, and brownish-coloured epithelium-scales, among 
which, in the less dark but somewhat transparent places, the 
pigment granules could be remarked. The latter, however, 
presented themselves with especial distinctness at the edges of 
the epithelium-scales, and appeared as irregular, rounded, flat 
granules, the border of which was dark, and the centre always 
clearer, but no nucleus was ever remarked in them. In the 
centre of the epithelium-scales they occasionally constituted 
a beautiful mosaic area of rounded, closely approximated, 
elongated, or sub-angular granules. Punctiform granules 
were more rarely met with. The moniliform arrangement of 
the granules was remarked more especially at the border of 
the epithelium-scales. The more transparent the epithelium, 
the more transparent, also, were the separate granules which 
then occurred isolated. The author seldom noticed a single 
isolated granule, for however few might be connected toge- 
ther, they were usually supported on a small particle of an 
epithelium-cell. When free, they were rounded or punctiform, 
and appeared connected in the form of a small rod or coronal. 
This description of the granular pigment does not agree, in all 
respects, with those given by other authors, as J. Vogel and 
Hofle. According to Vogel (¢ Path. Anat.’ p. 159), it con- 
sists of fine granular molecules of a brown or black colour, 
which are most usually contained in cells of various form and 
size. Occasionally, it would appear, these pigment-mole- 
cules occur free, particularly in the parenchyma of melanotic 
lungs. According to Hofle (Chemie v. Mikroskopie, p. 274), 
the pigment corpuscles are characterized by the intense black 
colour and almost immeasurable smallness of the constituent 
granules. According to him, they would seem never to be 
surrounded by a membrane, but frequently encompassed by 
a homogenous cortex, not differing from the substance con- 
necting the granules together. Henle (Allg. Anat., p. 282) 
is more inclined to the assumption of the cellular nature 
of the pigment-corpuscles, as Schwann states that he has 
noticed a molecular motion of the pigment-corpuscles within 


BLACK FUR ON THE TONGUE. 265 


the cell, which H6fle, on the other hand, declares to be im- 
possible, since molecular corpuscles can never perform any 
movements within a gelatinous substance. 

In the case now in question, the author never observed 
a cell or membrane, since the pigment-corpuscles rarely oc- 
curred in the free state, but were almost always deposited on 
or among the epithelium. They most resembled the pigment- 
corpuscles figured by Henle (1. c., Tab. I. fig. 12 D), in which 
also the border is dark and the centre somewhat clearer. 
According to him they are 0:0005-0-:0007” in the longest 
diameter, and about 1-4th as thick as long. Undera stronger 
power, Henle also noticed some as transparent as water. On 
some occasions, the author observed, on the borders of the epi- 
thelial-scales and connected with them, elastic fibres, distinctly 
characterized by their dichotomous mode of division. A few 
times he noticed filaments lying quite isolated, which very 
closely resembled the thallus-filaments figured by Henle (1. c., 
note, p. 29). They were never connected with the epithelial- 
cells, and exhibited perfectly cylindrical canals, without trans- 
verse septa, and beset externally with black points. The 
latter were in no case pigment-corpuscles, as they were globu- 
lar, which was particularly evident in the granules situated on 
the external borders, whilst the pigment-granules were always 
flattened, however small they might be. Even in the almost 
punctiform pigment-granules, the darker border could be dis- 
tinguished under favourable conditions of illumination. It is 
well-known that the granular pigment, besides its normal 
deposition in the corpus ciliare, in the pulmonary tissue, in 
the integuments, &c., is, for the most part, presented only in 
the most various pathological structures. In the tongue it has 
not yet been met with, especially to the extent in which it 
occurred in the present case. H6fle (1. c. p. 59) observed in 
five cases, in the fur of the tongue occurring in the healthy 
condition, dark-brownish bodies, partly of a cylindrical, partly 
of an irregular form, and with three or four times the circum- 
ference of the largest epithelial-scales, thickly beset with 
granules, and internally containing a sort of medullary body. 
He regarded this as an epithelial investment of the lingual 
papilla. These cases would seem to present no similarity 
with the instance observed by the author. H6fle could never 
effect a division of these bodies into separate epithelial-scales, 
which Dr, Eulenberg could always succeed in doing; nor 
could the latter ever observe the so-called medullary body ; 
and, as regards the granules, Héfle describes them as black, 
scattered points, whilst in the author’s case, they were aggre- 
gated in many ways, and represented roundish or angular and 


266 BLACK FUR ON THE TONGUE. 


flattened granules or plates, with dark borders, and, much 
more rarely, simple points. The dark epithelial-scales upon 
which the pigment-corpuscles were chiefly deposited, the 
author also regards as an epithelial covering of the papille. 

After he had observed the progress of the case for a sufficient 
length of time, and found that the phenomena remained un- 
changed, the author directed the internal use of an aqueous 
solution of chlorine, to be administered every three hours. 
After about two ounces of this medicament had been thus 
taken, not a vestige of the black coloration remained. The 
tongue had resumed its normal appearance, and the papille 
more of their natural size. The colour had not recurred 
even at the end of a year, so that the cure seemed to be 
complete. 


( 267 ) 


RE yi E Ws. 


Tue MicRoscoPpr, AND ITS APPLICATION TO CLINicaL Mepicine. By 
Lionet Beatz, M.B. London, Highley. 


WE suppose at the present day that there are few properly- 
educated medical men who would deny the value of the 
stethoscope as a means of ascertaining the presence of disease. 
The man who would be hardy enough to forego its use would 
run the hazard of even popular neglect for his temerity. 
This is not, perhaps, the case at present with the microscope, 
but we feel sure that whatever argument could be advanced 
in favour of the stethoscope, as a means of diagnosis, might 
be urged with tenfold force in favour of the microscope. 
The stethoscope, in fact, only facilitates the use of the organ 
of hearing; whilst the microscope widens and extends the 
power of vision, and creates a new world of observation. By 
it that which the unaided mind could only imagine, or vaguely 
indicate, as a probable existence, is demonstrated, and the 
structure, which was a puzzle and a mystery, becomes per- 
fectly understood. This instrument has now become a 
necessity for the anatomist and physiologist; no structure 
can be truly investigated, no function perfectly understood, 
without its aid. If, therefore, a knowledge of disease can 
only be obtained by a knowledge of the structure and func- 
tions of the body in health, it is necessary that those who 
undertake to treat disease should be conversant with the 
results of microscopic research. The microscope, in fact, 
should be put into the hands of every medical student, and 
he should be expected to be as well acquainted with the 
results of its use as he is of the scalpel, the test-tube, the 
stethoscope, or any other means of investigation. We fear 
this is not the case, and that many a young man passes his 
medical curriculum without even the inquiry being made as 
to whether he is acquainted with the powers of this mighty 
instrument of research. We are glad, however, to find that 
the means of microscopic instruction are multiplying. In 
many of our medical schools demonstrations with the micro- 
scope are given, our medical journals devote some portion 
of their space to micrological discussions, and here we have a 
professor in one of our metropolitan medical colleges, writing 
a book on the microscope especially adapted for medical 


268 DR. BEALE ON THE MICROSCOPE. 


students. We give Dr. Beale’s remarks on the value of the 
microscope as a means of diagnosis, entire. 


“<Tt may be well here briefly to refer to a few of those instances in 
which the microscope is known to have afforded valuable aid to the 
practitioner in the diagnosis of disease. 

“ Diseases of the Kidney.—There is no class of diseases in which its 
powers have been more advantageously brought to bear by the practical 
physician, than in those of the kidney. By a microscopical examination 
of the urine, we are frequently enabled to ascertain the nature of certain 
morbid changes which are going on in the kidney, and even to distinguish, 
during life, the existence of certain well-defined pathological conditions of 
that organ. The laborious researches of Dr. Johnson have shown us how, 
by the peculiar character of the casts (fig. 1) of the uriniferous tubes, 
which are found in the urine, 
we can ascertain whether the 
epithelium be desquamating, 
or, on the other hand, whether 
it presents no such tendency, 
but remains firmly attached to 
the basement membrane of the 
tube. If the epithelium be un- 
dergoing that peculiar change 
termed fatty degeneration, we 
shall often be able to ascertain 
the fact by examining a spe- 
cimen of the deposit from the 
urine by the microscope. So 
again, by the presence of cer- 
tain other deposits, and a 
knowledge of the symptoms usually associated with them, the physician 
is enabled to direct his attention, as the case may be, to the existence of 
local changes, affecting some part of the genito-urinary mucous membrane, 
or to more general disturbance, in the changes which take place in primary 
and secondary assimilation. 

“ Fatty Degeneration.—Of late years, the remarkable changes which 
Fie. 2 take place, and which have been described 

ah under the name of fatty degeneration, in some 
of the highly complex textures of the body, 
in consequence of which their properties be- 
come changed, and their functions impaired, 
or altogether destroyed, have been undergoing 
careful investigation by a vast number of 
highly-talented investigators. 

“The recent discovery of a state of fatty 
degeneration affecting the arteries of the 
brain (fig. 2), in the majority of cases of 
apoplexy, by which the strength of their 
‘ coats becomes deteriorated, and their elasticity 
a) entirely destroyed, would tend to lead us to 
‘ infer, that this disease is dependent rather 
Ss, upon complicated changes affecting nutrition, 
than upon the presence of a condition of ple- 
thora or hyperemia, as was formerly sup- 
posed, and acted upon. 

“The connexion between fatty degeneration 


DR. BEALE ON THE MICROSCOPE. 269 


of the margin of the cornea (arcus senilis), and similar changes taking 
place in the muscular tissue (fig. 3), of the heart (a subject which has 
been carefully investigated by Mr. Canton), or in Fie. 3 
the cerebral vessels, must be regarded with great 1B He 
interest by every practitioner. 

*« The microscopical examination of the matters 
vomited in certain cases, has proved to us that the 
presence of minute fungi, originally discovered by 
Professor Goodsir, and named by him Sarcine 
Ventriculi (fig. 4), occurs in connexion with 
certain morbid conditions of the stomach. These 
remarkable cases are much more frequently met 
with than was formerly supposed, and form an 
exceedingly interesting class of diseases. 

“ Tumours and Morbid Growths—The micro- 
scope has many times afforded important aid in 
the diagnosis of tumours, although it has certainly failed in many instances ; 
which circumstance has been brought forward by : 
some as an argument against its employment Fig. 4. 
altogether. After careful microscopical examina- ~ 
tion, the best observers have failed in deciding as 
to the nature of a particular tumour submitted to 
examination ; and they have been unable to pro- 
nounce as to its malignant or non-malignant cha- 
racter. On the other hand, not unfrequently this 
question has been positively and correctly an- 
swered in the affirmative or negative, and therefore it would surely not be 
right altogether to discard the use of an instrument which, although 
eminently useful in many instances, is not infallible ; for it would appear 
to be the opinion of some, that the use of the microscope ought to be 
altogether abandoned, in the diagnosis of tumours, We shall have to 
return to this important question at a future time. 

“* For the discovery of Imposition, the microscope is invaluable, as it 
almost necessarily follows that, in consequence of the frequency with 
which urine is subjected to minute investigation, patients often resort to 
various expedients to deceive the practitioner. Perhaps flour, starch 
(fig. 5), sand, and milk, are more frequently employed for this purpose 
than any other substances. The microscope will obviously enable any 
one to detect the first three. If milk be added to urine, the mixture may 
very readily be mistaken for a specimen of the so-called chylous urine. 
Although a considerable quantity of fatty matter is present, in either case, 


Fig. 5. Fig. 6. 


this fatty matter exists in a very different state. In milk, we find the 
oil-globules (fig. 6), so characteristic of this fluid, while, in true chylous 


270 DR. BEALE ON THE MICROSCOPE. 


urine, not a single oil-globule can be found, although the specimen may 
contain a large quantity of fatty matter in a molecular state (fig. 7). 

“ Larve of the Blow-fly in Urine.—A_specimen of urine containing 
several bodies of about half an inch in length, and of a rounded form, was 
once sent to Dr. Todd for examination. The bodies in question looked 
not unlike the larve of some large fly, but, as it was confidently affirmed 
that they were passed by the urethra of a gentleman, the accuracy of this 
view of their nature was doubtful. 

“Upon placing a portion of one of them under the microscope, trachez 
(fig. 8)—(the air-vessels charac- 
teristic of the class of insects) were 
observed in considerable numbers ; 
and this circumstance alone enabled 
me to say positively that they were 
not entozoa, and that they could not 
have been passed in the manner 
stated. They were afterwards proved 
to be the larvz of a fly. 

““The claws of echinococci and 
portions of hydatid cysts have on 
“ several occasions been discovered in 
the urine, sputa, &c., upon submitting portions of these fluids to micro- 
scopical examination, proving beyond a doubt the existence of hydatids. 

““ Substances passed by the Bowels.—If the practitioner have a good 
knowledge of the use of the microscope, he can often ascertain the nature 
of substances passed from the alimentary canal; and, by the aid of this 
instrument, he can often at once decide as to the nature and origin of 
substances, which, to the unaided eye, only present most doubtful cha- 
racters. Considerable perplexity has arisen from the presence of bodies in 
the stools of patients, which afterwards proved to be portions of almonds, 
gooseberry skins, portions of potato, the testa of the tamarind, husks of 
wheat, &c.: not many years ago the uredo of wheat was mistaken for, and 
described as, a peculiar fungus, to which it was supposed the phenomena 
observed in cases of cholera were due. 

“« Portions of vessels which, unlike the other constituents of the food, 
have resisted the process of digestion, have been met with in the feces, 
and mistaken for small intestinal worms, which they much resemble when 
examined by the unaided eye. Upon being subjected to microscopical 
examination their true nature was readily discovered. 

“In Medico-legal Inquiries the microscope has often afforded valuable 
aid. The distinction between blood spots and red stains produced by 
fluids resembling blocd in colour,—between human hair and that of 
animals,—and the detection of spermatozoa in cases of rape, need only be 
adduced as examples of the importance of the microscope in such 
investigations. 

“‘ For detecting Impurities in Food and Drugs the microscope has 
afforded important aid, and there are several other purposes to which it 
may be applied, some of which will come under consideration in a 
subsequent chapter.” 


These are some of the positive uses of the microscope in the 
investigation of disease, uses which ought at once to arrest 
the attention of the mere “ practical man,” but its importance 
is even greater in those instances where it corrects our theories 
of life and disease, and thus becomes the means of modifying 


DR. BEALE ON THE MICROSCOPE. 271 


a whole system of practice. It is thus that it lays the axe at 
the root of spurious systems of medicine, and is certain to 
bring about the destruction of all absurd generalizations, 
whether they go by the name of homeopathy, hydropathy, or 
more legitimate terms. 

We give one other extract as a specimen of Dr. Beale’s 
book. It relates to a class of substances, of which there is, 
at present, much to learn both in health and disease :— 


“‘ Creatine—Creatinine.—Creatine exists only in very small quantity 
in muscular fibre. According to Dr. Gregory, it is most readily pre- 


Fig. 216. 


pared from the flesh of the cod-fish ; from 25 lbs. of which, in one experi- 
ment, he obtained 164 grains of creatine. The flesh is to be chopped in 


Fig. 217. 


small pieces, and well kneaded with water. After all the fluid has been 
expressed by powerful pressure, it is very carefully raised to the boiling- 


272 DR. BEALE ON THE MICROSCOPE. 


point, and the coagulated matter removed by filtration. The phosphatic 
salts are precipitated by caustic baryta. The solution must be again 
filtered, and evaporated at a gentle heat (130°-140°) to about one-twentieth 
of its volume, or to the consistence of syrup; any scum which forms 
being, from time to time, removed from the surface. This concentrated 
solution may then be set aside. On cooling, it forms a thin jelly, and, 
after standing for some time, crystals of creatine are deposited. 

“Crystals of creatine are represented in fig. 216, and those of creatinine 
in fig. 217, which have been copied from M. Robin’s Atlas (see 272). 

“Liebig obtains creatine and creatinine from urine, by evaporating the 
fluid, after the precipitate produced by the addition 
of lime-water and chloride of calcium has been 
separated by filtration.. During evaporation, the 
oreater part of the salts are deposited, and the 
mother-liquor is treated with 1-24th of its weight 
of chloride of zinc: after some days round granules 
separate; these are composed of a compound of 
chloride of zinc and creatinine, with which the 
creatine is mixed (fig. 218). The granules are 
dissolved in boiling water, and treated with hy- 
drated oxide of lead, until the reaction becomes 
alkaline. The fluid is next filtered, decolorized with animal charcoal, and 
evaporated to dryness. The residue consists of creatine and creatinine, 
the latter of which may be removed by boiling alcohol, in which creatine 
is almost insoluble.” 


Fig. 218. 


We cannot speak more highly of Dr. Beale’s book than to 
say that we should be glad to see a copy in the hands of 
every medical student and every medical practitioner in the 
kingdom. Those who have employed the microscope will 
find it of great assistance, whilst those who have not yet com- 
menced the use of this instrument cannot fail, we should 
think, by the perusal of a volume like the present, to be con- 
vinced of its importance in the investigation of disease. The 
work abounds with beautifully executed wood-cuts, and is 
got up in the best possible style. 


Diz INFUSIONSTHIERE, AUF IHRE ENTWICKELUNGS-GESCHICHTE UNTER- 
sucuT. (The Infusoria investigated with respect to their development.) 
By Dr. F. Srery. Leipsic. 1854; pp. 265. 4to. Plates. 


To no one have we been more indebted of late years for our 
advanced knowledge with respect to the Infusoria than to 
Dr. Stein. His previous writings in Wiegmann’s Archiv 
for 1849, on the development of the Infusoria, and on the 
same subject, together with observations on their more inti- 
mate structure in Siebold’s and KGlliker’s Zeits. f. Wiss. 
Zoologie in 1851, as well as his first Essay on the nature of 
the Gregarine in Miiller’s Archiv for 1848, have stamped 
him as an original observer and thinker, and have not only 


DR. STEIN ON THE INFUSORIA. 273 


added very materially to our previous knowledge of ‘those 
subjects, but have also in so doing aided very efficiently in 
the dissipation of numerous erroneous views, propounded by 
Ehrenberg and other early microscopists. It may be as well 
therefore, briefly to state what points connected with the 
Infusoria have been made out mainly by the author of the 
present work, and in what state he leaves the question to 
which chiefly he has addressed himself, viz., the development 
and metamorphoses of certain classes of Infusory animalcules. 

Led by his observations on the structure and habits of the 
Gregarine to conclude that they certainly belonged to the 
animal kingdom, and represented, in fact, the ‘animal’ in its 
simplest form, he was obliged to consider what place they 
should hold in the zoological system. In order to decide this 
it was requisite to ascertain distinctly the organization and 
structure of the Infusoria, and to decide whether Ehrenberg’s 
view, according to which all the Infusoria were furnished with 
a complex digestive apparatus, with male and female sexual 
organs, and with muscles and nerves, were correct, or whether 
the more rational views propounded by Focke, and especially 
by Dujardin, as to their much more simple constitution should 
be adopted. According to which the structure and organiza- 
tion of the Infusoria is not more complex than that of the 
Gregarine ; and most of their vital functions are performed 
without any special organs, 

One result of Siebold’s observations, which upset Ehren- 
berg’s erroneous notions of the nature of certain organs which 
he supposed to be connected with the generative function, was 
to prove that a certain body described by Ehrenberg as the 
testis, though it had not the significance of such an organ, was 
nevertheless essentially related to the function of reproduc- 
tion. This body was termed by Siebold the ‘ nucleus,’ and 
it appears to form a pretty constant element of the body of 
most Infusoria, at any rate in one phase of their existence, 
** This nucleus,” says Siebold, “‘ whose presence gives the 
Infusoria a resemblance to a cell, demands very special atten- 
tion, inasmuch as it does not at once perish after the death 
of the animalcule in which it was contained. Probably,” he 
goes on to say, “this nucleus is subsequently developed into 
a peculiar animal, and, in fact, many Infusoria are only the 
larve of other animals, whose complete cycle of metamor- 
phoses has not yet been made known.” In adducing the 
Euglena viridis, as an instance in which he had observed the 
development of the so-termed ‘nucleus,’ Siebold notices the 
fact of its surrounding itself with a sort of capsule or cyst, a 
circumstance already remarked by Ehrenberg ; and it was this 

VOL. Il. U 


274 DR. STEIN ON THE INFUSORIA. 


notice of the occurrence of an encysting process that first 
attracted Dr, Stein’s attention, who had been struck by the 
remarkable correspondence in many respects between the 
motions and structure of the Huglene with those of the Gre- 
garine. The addition in the former creature of an ‘ eye-spot’ 
did not appear to him justly to entitle the Euglene to a higher 
rank in the zoological scale than the Gregarine, rR as 
that spot has none of the attributes of an organ of vision, 
appearing to be nothing more than a particle of pigment. 
The Huglene moreover, and this was the point which princi- 
pally struck Stein, became encysted like the Gregarine. He 
felt it necessary to inquire whether the encysting process was 
of the same import in the one case as in the other. Nothing 
appeared to support the notion, propounded by Ehrenberg, 
that the Huglene became encysted only at the moment of 
death ; according to all analogy he was compelled to suppose 
that the formation of _the cyst of the Euglene was the com- 
mencement of a process of propagation. 

Here was a new starting point in the inquiry respecting the 
mode of development of the Infusoria, and from this point 
Stein started, and where he has arrived travelling in this path 
is shown in the works above cited, but chiefly in that which 
forms the subject of the present notice, 

His attention was naturally led in the first place to the 
Euglene. . 

In a glass, in which were contained a great variety of 
ciliated Infusoria, and among them also numerous individuals 
of Euglena viridis, Eacus, and Edeses, he remarked after the 
lapse of some days the formation of a thin film on the surface 
of the water, composed of an interlacement of confervoid 
filaments and Oscillatorie. ‘This film swarmed with Euglene, 
many of which had lost their beaks and crawled about with a 
worm-like movement among the Conferve and Oseillatori 1@- 
filaments. Besides these he discovered to his great joy a great 
many transparent, gelatinous, or quite soft cysts, which some- 
times contained only a single Euglena contracted into a 
globular form, sometimes two of a hemispherical form ap- 
pressed together. The encysted Euglene proved to be still 
living, inasmuch as they moved about in the cysts, and if the 
cysts were ruptured the previously globular individuals re- 
assumed their pristine elongated figure, and crawled about 
in the same manner as the other beakless individuals among 
the conferve. 

For what purpose was this encysting? The cyst was 
evidently intended for something more than a coffin. Further 
observations soon showed that the encysting process of the 


DR. STEIN ON THE INFUSORIA. 275 


Euglene had really reference to their multiplication. The 
process, however, appeared to be different in Euglene from 
that in the Gregaring, inasmuch as in the latter case two 
individuals are conjoined before the cyst is developed, whilst 
in the Huglene the case is formed usually around but one. 
For where two individuals were found enclosed in a cyst, it 
was at once apparent that they had proceeded from the divi- 
sion of an originally single individual, 

Whilst thus investigating the Huglene, his notice was also 
directed to other forms of Infusoria contained in the same 
water, such as Paramecium aurelia, Prorodon niveus, and 
Holophrya discolor, the latter two of which species he fre- 
quently observed enclosed in well-defined gelatinous cysts ; 
and as these Infusoria belonged to quite another principal 
division of the class, he began to hope that the process of 
becoming encysted would probably turn out to be of general 
occurrence in the Infusory world. 

This proved to be the case, and the work then proceeds to 
describe the way in which Dr. Stein was led to detect the 
connexion between Epistylis plicatilis with a species of Ehren- 
berg’s genus Acineta; an observation which pointed the way 
in his future researches. One of his earliest additional obser- 
vations was that of the heterogeneous generation of Epistylis 
digitalis. (n this species he traced first the metamorphosis 
of the Epistylis into an Acineta, and secondly, observed in the 
latter the extraordinary fact of the development and evolution 
of a Trichodina, a discovery which Ehrenberg has attempted to 
explain by the supposition that the Tr ichodina had been pre- 
viously swallowed by the Acineta. Dr. Stein’s important 
researches are continued through the family of the Vorticelline, 
and his observations given upon Actinophrys, Podophrya, the 
genus Trichodina, and on the nature of the Opaline, the 
propagation of Chlorogonium euchlorum and Vorticella micro- 
stoma, and particularly upon the quiescent condition of the 
latter Infusoria ; upon Spzrochona gemmipara and S. Schentenii, 
and upon the Acineta state of Dendrocometes paradoxus, Zoo- 
thamnium affine, &c. Ke. 

The concluding chapter is concerning Paramecium bur- 
saria, Ophridium versatile, Nassula ambigua, and Glaucoma 
scintillans. 

The bulk of this mass of original and valuable observations 
precludes our giving more than the above meagre outline of 
their purport, nor will our space allow of our making any 
copious extracts. 

We are a little surprised to find that Dr. Stein is still 
inclined to retain some suspicion as to the correctness of the 

u 2 


276 DR. STEIN ON THE INFUSORIA. 


more modern views, according to which the family of the 
Volvocine should be referred to the vegetable kingdom ; but, 
as he justly observes, however this may be, his observations 
will still be valuable as showing how extraordinarily near 
the development of the lowest plants is related to that of the 
lowest animals. 

With respect to the development of Volvox globator, Dr. 
Stein’s observations agree very closely with those of Mr. 
Williamson and Mr: Busk, recorded in the ‘ Transactions of 
the Microscopical Society,’ and contained in our last volume, 
but they add nothing to the results arrived at by those writers. 
And with respect to the existence of more than one mode of 
propagation with Volvox globator, Dr. Stein’s observations 
have led him to precisely the same conclusions as those at 
which Mr. Busk had arrived, and with which Dr. Stein ap- 
pears to be unacquainted. After describing, for instance, the 
usual mode of multiplication by segmentation of certain of 
the zoospores, Dr. Stein proceeds to observe that this mode 
of propagation does not explain the appearance of Volvox 
globator in localities which had been completely dried up and 
afterwards refilled with water, or which had for a long time 
been dry land. There must, as he says, be another mode of 
propagation, in which germs are produced which do not suffer 
injury from the drying up of the water, and are capable of 
being dispersed through the air. 

These ‘ winter spores,’ as they may be termed, constitute 
the forms termed Volvoz stellatus, which, together with V.aureus, 
Mr. Busk had already stated should be regarded as forms of 
V. globator, and as representing the ‘ winter, or quiescent 
spores of other Alge. Dr. Stein’s view of V. aureus differs 
somewhat from that of Mr. Busk; he regards it as the qui- 
escent form of a distinct species of Volvox, to which he assigns 
the name of V. minor, But the distinction he draws between 
the two does not appear sufficient to justify their separation, 
The chief difference, according to him, between V. globator 
and V. minor consists in the circumstance that in V. globator 
eight young colonies are produced, whilst in V. minor the 
number is very inconstant, varying between one and nine, most 
usually four. The formation of a second coat around the 
quiescent or gold-coloured spore is described by him, as it is 
figured and described in Mr. Busk’s paper. 

We must now conclude our notice of this highly-valuable 
work, which is indispensable to those who may make the 
nature and development of the Infusoria the subject of study. 


CATALOGUE OF MARINE POLYZOA. 277 


CaTaLoGuE oF MARINE PoLyzoA IN THE COLLECTION OF THE BRITISH 
Museum. Part II. (Cheilostomata, Port.) 

Tuis second part of Mr. Busk’s illustrated catalogue of 

Marine Polyzoa concludes their first subdivision, including 

the Cheilostomatous subclass, or the Celleporina of authors. 

The families contained in it are as follows :— 


Species. | Species, 
Fam. 10. Membraniporide. | Fam. 13. Vinculariade. 
Membranipora . 16 Vineularia . . 1 
Lepraia. . . 46}  ,,. 14. Selenariadz. 
» Ll. Celleporide. | Capularia 5 
Cellepora. .. 8 | Lunulites . 4 
» 12. Escharide. Selenaria. 1 
Eschra . . ~ 11} 
Retepora. . . 3) 


As in the former part, magnified figures are given of every 
species, and a short appendix is added, containing the sub- 
stance of Mr. Busk’s observations upon the nature, structure, 
and uses of the avicularian and vibracular organs of the 
Polyzoa, which were communicated in a paper read before 
the Microscopical Society, and published in their ‘ Transac- 
tions. The importance of these organs in a systematic point 
of view, in the classification of the Polyzoa, is exemplified 
in the Catalogue, and may be judged of from the fact, that 
of thirty-six genera therein described, twenty include species 
armed with either vibracula or avicularia, or with both; and 
that of 191 species, no less than 126 are furnished with 
avicularia or vibracula. 


Tue Microscope, 1rs History, Construction, AND APPLICATIONS. By 
JaBezZ Hoee, M.R.C.S, London, Orr and Co, 
Ir is a pleasing task to us to have. to notice so many works 
as guides to the use of the microscope. Although these are not 
all of equal merit, they clearly indicate that there is a demand 
for instruction, and that the value of this instrument, as a 
means of observation, is making sure and certain progress. 
We are glad also to find, in the literature of microscopy, 
a tendency to seek a wide field of demand, by placing a low 
price on the works issued. We do not see why our intelligent 
artizans should not have the field of their vision increased 
and the pleasures of their life multiplied by the use of this 
instrument, as well as those who possess more of this world’s 
goods than themselves. On this account we can strongly 
recommend Mr, Hogg’s volume. It is not only well got up 
with a large number of plates, and woodcuts, but it is very 
cheap. This volume might be called “the microscope for the 


278 MICROGRAPHIC DICTIONARY. 


people.” We hope our better microscope-makers will take 
the hint, and see if they cannot manufacture a microscope 
that a working man can afford to buy, and yet so good that he 
may be able to recognize with it the more interesting forms of 
microscopic structure and life. Such a microscope is wanted 
for schools, and the maker who will construct one of this kind 
for twenty or thirty shillings, will not only probably make his 
fortune, but be a benefactor to his race. 

It is impossible for us to give, in detail, an account of 
Mr. Hogg’s book. It is what its name implies—a cyclo- 
pedia of information on all subjects relating to microscopy. 
The author seems to have collected information from every 
source, and we are glad to find he has recognized in our pages 
so large a quantity of the interesting and useful contents of his 
volume. We do not like to find fault, but there are some 
things in the printing the book—mere matters of taste— 
which we hope to see altered in a second edition. In the 
meantime, they do not detract from the value of the inform- 
ation, 


THE Micrograruic Dictionary, Parts I, and Il. By J. A. GRIFFITus, 
M.D., and A. Henrrey, F.R.S. London, Van Voorst. 


Aut possible microscopical subjects are to be treated of in 
this volume in an alphabetical way. Both the authors are 
known as good microscopic observers, and the two parts of 
the work before us promise well. The plates are accurately 
executed, and the Micrographic Dictionary, when complete, 
will, we make no doubt, be a standard work on the subjects 
of which it treats. We shall notice it more at length as it 
proceeds. 


THE AQUARIUM AN UNVEILING OF THE WONDERS OF THE DEEP SEA. By 
Pattie Henry Gosse. London, Van Voorst, 
WE are beginning to connect Mr. Gosse’s name with the 
sea-side. For the future, when he announces a book, we 
shall conclude that it is to detail more of his pleasant expe- 
riences on the sea-shore, and to shed further light on our 
knowledge of the habits and manners of the tenants of the 
deep. Who that has seen the aquavivarium (we prefer this 
word to aquarium) i in Regent’s Park, has not longed to have 
a tank in their study or drawing-room ? Who has not felt 
that beautiful and wonderful as plants are, animals are more 
wonderful still. One of the objects of Mr. ‘Gosse’s book is to 
give directions for keeping and:domesticating marine animals. 
Our wood anemonies in Ward’s cases are to be supplanted 


GOSSE’S AQUARIUM. 279 


by sea~anemonies in Mr. Gosse’s vases. Instead of dogs and 
cats we are to have dog-fish and cat-fish. Our gold carp is 
to be supplanted by the ancient Wrasse, and the corals on the 
fire-place are to give way to living corals working in a little 
ocean of their own. But what has this to do with the micro- 
scope? Very much. All the animals that can be kept in 
the aquarium, afford interesting employment for the micro- 
scope. Much yet remains to be known of the structure of 
many of the creatures which are most. easily kept in this 
artificial manner. To those who would wish to examine 
these creatures we recommend Mr. Gosse’s volume. It 
has several illustrations done in chromolithography, and 
also wood engravings of scenery and natural objects, and 
is, throughout, written in Mr. Gosse’s usually felicitous 
style. 


BoTanIcAL AND PHysroLogicAL Memoirs. Ray Socrery. 


Tuts volume consists of Professor A. Braun’s Treatise on 
Rejuvenescence in Nature, Menighini on the Animal Nature 
of Diatomez, and Kohn on the structure of Protococcus plu- 
vialis. Three more valuable or important works to the 
microscopist, at the present time, we could hardly mention. 
In Braun’s Essay will be found one of the most complete 
accounts of cell-development extant. His general views will 
be looked upon by English readers as speculative, but they 
are full of sound thought based upon extensive and accurate 
original observation. ‘The remarks of Menighini will be read 
with greater interest in this country, just now, than at any 
other time, as at no past period have the structure and func- 
tions of the Diatomacez attracted so much attention as at the 
present. The paper of Kohn, on the Protococcus, has also, 
especial interest, when the question of the nature of animal 
and vegetable functions is being so keenly discussed. We 
must give the Council of the Ray Society credit for descrying 
the signs of the times, in publishing a volume so entirely 
devoted to microscopic research as this. We are glad also to 
find that this Society has undertaken to publish other works 
interesting to the microscopical observer, such as Professor 
Allman on the British Fresh-water Zoophytes, Bowerbank 
on the British Sponges, and Williamson and Carpenter on the 
Foramnifera. 


( 280 ) 


NOTES AND CORRESPONDENCE. 


Description of a Wiagmetic Stage to the Microscope.-—Some time 
ago, at one of the meetings of the Microscopical Society, 
the model or perhaps the incomplete stage itself of a micro- 
scope was exhibited, in which Mr. King, of Bristol, if I 
remember rightly, had applied a magnet for the purpose of 
retaining a soft iron object-bearer, and at the same time of 
allowing it to be moved about in all directions with great 
smoothness and facility. I am not aware whether the inventor 
ever carried the design further into effect, but as the idea 
struck me as highly ingenious, and capable of very useful ap- 
plication, [ have endeavoured to carry it out in the following 
simple manner, The contrivance, it should be remarked, can 
only be applied to a simple stage, that is to say, to a stage 
consisting of a single plate. The 
magnetic force is contained in two 
semicircular magnets of hard steel 
8 9 (fig. 1), which are fixed on the 
under side of the stage, one on 
N s either side of the opening, with 
E ua whose size the curve of the mag- 
nets should of course be made to 
correspond. The force is con- 
veyed to the upper side of the 
stage by means of four soft iron 
pegs passing through four holes 
drilled in the stage, at points as 
near as may be corresponding with the four poles of the 
magnets, as at 0,0, 0,0 (fig. 1). The iron pegs should slightly 
exceed the thickness of the stage in length, and should have 
a thin flattened head (fig. 2). 

When inserted in the holes, into which they should 

Fig. 2. fit closely, the magnets are screwed down upon the 
gE heads so as to be in close contact with them. All 
that is now requisite to be done is to see that the ends 

of the pegs, which project through the stage, are pre- 

cisely in the same plane, and raised about a hair’s breadth 
above the surface of the stage, so as not to interfere with its 
level when used in other ways, and yet, at the same time, 
to prevent the object-bearer from coming in contact with 
the stage itself, by which its free movement would be inter- 
fered with. The object-bearer, which is made of thin soft 


Fig. 1. 


ig 


MEMORANDA. 281 


iron, may be of any form or dimensions; that which I have 
found useful, is of the shape shown in fig. 3. 


Fig. 3. 


The ends of the bearer being made to project beyond the 
sides of the stage, and being tapered off, serve as handles by 
which it may be most conveniently moved in any direction, 
with one or both hands, and as readily, if not more so, as by 
the usual screw-heads or lever of a compound stage. 

In the case of a live-box all that is necessary is to have the 
plate, upon which the upright part is fixed, made of soft iron 
instead of brass, to do away with the need of any other bearer. 
It is very important that the under surface of the iron object- 
bearers should be ground true and made very smooth, which 
may be done easily enough with a water of Ayr stone and fine 
emery-paper. 

The advantages of this stage are the following :— 

1. That the stage may be made very thin. 

2. The universality of the movements, and the ease and 
simplicity of their execution by one or both hands. 

3. Its trifling cost. 

In conclusion, I would merely remark, that whatever credit 
is due for the original idea of a magnetic stage to the micro- 
scope belongs, as I believe, to Mr. King, of Bristol, and that 
it is only in following out the suggestion thus derived from 
him that I was led to the simple contrivance above described, 
in the execution of which I was assisted by Mr. Hudson, 
optician in Greenwich.—G., Busk. 

Nore.—Since writing the above I have been kindly favoured 
by Mr. King, No. 1, Denmark-street, Bristol, with an account 
and sketch of his contrivance. It is more complicated, rather, 
than the one above described; but is very ingenious, and, 
perhaps, if carried out practically by him, which has not yet 
been done, might, in some cases, be superior. It has the 
disadvantage, however, of not allowing the stage to be so thin 
as my contrivance does.—G. B. 


Meaning of the word “ Unscheinbarkeit.” --[t cannot be denied 
that one meaning of the word “ Unscheinbarkeit” is ‘* un- 
sightliness.” This is beyond all doubt; and it may be 


282 MEMORANDA. 


admitted that in certain cases, the word might have the mean- 
ing attributed to it by Dr. Gregory (Q. J. Mic. Se. vol. Il. 
p- 201), although, perhaps, such meaning would be better * 
expressed by ‘“ Unsichtbarkeit,”’ or ‘ Unbemerkbarkeit.” 
But in the place where Fresenius uses the word, he is speak- 
ing not of the organs of Fungi, but of the tribe generally, to 
which the attribute of “want of obvious perceptibility”’ cer- 
tainly does not belong. Moreover, the difficulty of studying 
Fungi, owing to theit minuteness and the delicacy of their 
organs of fructification, is specially referred to by Fresenius, 
in the very next line, and it is not, therefore, probable, that 
he intended to use the word ‘“ Unscheinbarkeit” in a sense 
which would make the next sentence but one of mere tau- 
tology. Again, a little further on, the author says, that the 
causes he has mentioned may account for the neglect of the 
study of Fungi by those persons whose main object is, that 
their collections of plants should have a striking, neat, or 
elegant appearance. I think I have said sufficient to show 
that Fresenius did not use the word to express “ want of 
obvious perceptibility.” ‘ Unsightliness’” may be rather a 
strong expression, but we have no other single English word 
which would at all convey the author’s meaning. It might be 
paraphrased by “ insignificance of appearance,” “‘ meanness of 
appearance,” or “ want of power to captivate the eye.” —THE 
Reviewer OF Fresenius’ Mycotoey. 

On colouring Animalcales.—[n feeding infusorial animalcules 
with carmine, one very great disadvantage presents itself, viz., 
the field of view becomes crowded with the dark particles of 
carmine, by which the object is hidden from correct observa- 
tion, and the eye embarrassed ; another is, the length of time 
often required to render the gastric organs visible, owing to 
the slow imbibition of the carmine. 

These difficulties, I think, may be obviated by the use of 
the red pigment which lines the cornea of the common house- 
fly. Ihave tried it for two years, and, without an exception, 
in every case, found it devoured with avidity by the carni- 
vorous animalcules, and from its being capable of such minute 
division, the field was left almost as clear as before the addi- 
tion of it. The ciliary vibrations were perfectly distinct, and 
a beautiful bright red speedily made its appearance in the 
internal organs of the smallest animalcule present, while, in 
some cases, the larger crustacean Daphnia, &c., appeared as 
if their blood had become coloured with it. 

If you consider these simple suggestions of any service to 
your readers, they are perfectly at your disposal_—Tuos. C. 


WuirteE, 65 Warwick Street, Pimlico. 


MEMORANDA, 283 


Three new British Species of Diatomacez.—In the course of 2 
recent examination of the deposits of some of our tidal har- 
bours, the following species of Diatomacee have come under 
my notice; and as they have not been ‘figured, as far as I am 
aware, in any former publication, I annex camera drawings, 
with a short description of each, the insertion of which may 
prove interesting to some of the readers of your valuable 
Journal.. 

Triceratium armatum, n. s. (Fig. 1.)—Frustules large, with 
straight or slightly con- 
vex “sides ; ; angles pro- 
duced into long horn-like 
processes, with rounded 
extremities; cellular struc- 
ture minute, partially ra- 
diating towards the sides 
and angles; six or more 
spinous processes project- 
ing from the surface of 
the valve. 

I have seen three speci- 4 
mens of this fine Trice- SD RE ere AN 
ratium, sent me by my pa ’ ™s 
friend, F. Okeden, Esq., 
from Neyland and other localities, near Haverfordwest. It ap- 
proaches nearly to the 7) tridactylum, Ehr., of Mr. Brightwell, 
from Petersburg, Virginia,* but differs in the size and form 
of the angles, and in wanting the siliceous plate that extends 
beyond the sides of that species. Professor Bailey has 
described a form from the same locality, with four lateral 
spines, which he named 7. spinosum ; but, from his descrip- 
tion and figure in Silliman’s Journal,t I cannot satisfactorily 


Fig. 1. 


identify it with the Neyland spe- Ke 3 

cimens, I therefore venture to apply my 

the specific name of armatum. The a 

spinous processes are very similar FX 

to those which occur on some spe- yr 

cies of Eupodiscus. LY YA 
Triceratium comtum? Ebr. (Fig. a 

2.)—Sides straight or slightly con- e aeges: egenee 

vex, with a row of cells projecting . gee My 

above the margin of the valve; the Cc Fx Ra 304 i Mae s 


horn-like processes at the angles 
short and obtuse ; cellular structure large. 


* Journal of Microscopical Science, vol. i. t. 4, f. 3. 
+ Vol. xlvi. t. 3, fig. 12. 


284 MEMORANDA. 


Specimens of this species were sent me, along with the 
preceding, from the same deposit, and appear to agree very 
closely with the figure given by Mr. Brightwell in the first 
volume of the Microscopical Journal.* The cellular mark- 
ings are as large as in Z. favus, and I am rather doubtful 
whether it may not be a young form of that species; but the 
length of the angular processes and fringe-like row of cells at 
the margin appear to give it a distinctive character. It has 
not hitherto, I believe, been figured as British. 

Doryphora? elegans, n.s. (Fig. 3.)—Valves obovate, divided 
by a median line, with transverse striae, disposed 
in curves, concentric with the extremities ; the i in- 
terspaces occupied by minute cells. 

This pretty little species I met with in some 
mud from Pembroke harbour; in form and struc- 
ture it approaches the Natal specimens described 
as Euphyllodium spathulatum by Mr. Shadbolt ;+} 
but I have lately heard from Mr. Brightwell that similar forms 
were previously referred by Mr. Smith to the genus Doryphora, 
and as his absence from England precludes me from submit- 
ting the specimens for his determination, I adopt his generic 
appellation. Until living specimens are obtained it must be 
considered a doubtful form; but if stipitate, it would be in- 
cluded in the second sub-tribe of Mr. Smith’s Synopsis; and 
in structure would be nearer Doryphora, or Rhaphoneis of 
Kutzing, than‘any other genus. The structure of the valve is 
exactly similar to that of the Natal specimens, but differs in 
being smaller and less ovate. All the figures are drawn to 


a scale of 400 diameters.—F. C. S. Roper. 


Fig. 3. 


Since writing the preceding note I have received the 
following description of the habitat of the two species of 
Triceratium, and I have reason to believe that the same de- 
posits will yield several other curious forms. ‘The first 
specimen of this species (J. armatum), I found in a sample 
of the alluvial mud deposit at Neyland, which is a Creek of 
Milford Haven. The mud was obtained from a depth of 
twenty feet, with a boring tool constructed for the purpose ; 
I have since found it in a surface gathering from the same 
locality, and it also occurs in the upper deposits of the 
River Cleddon, within a mile of Haverfordwest. The other 
species of Triceratium occurs rather abundantly in the gather- 
ing from Neyland at twenty feet depth.”—Firzmaurice 
OxkeDEN, C.E. 


* Journal of Microscopical Science, t. 4, f. 4. 
+ Ibid., vol. ii. p. 41. 


MEMORANDA. 285 


On the Illumination of Transparent Objects.— | shall feel greatly 
obliged if you will insert in the next number of the ‘ Quarterly 
Journal of Microscopic Science’ a few observations on Mr. 
Wenham’s last paper on Microscopic Illumination, in reply 
to some strictures made by him on a communication of mine 
upon the same subject. 

I have no wish to impute to Mr. Wenham any other than 
the best motives, and I trust in the remarks which I am 
about to make he will give me credit for the same. 

My principal object in the communication which you were 
so kind as to publish on the subject of microscopic illumina- 
tion was to detail certain facts, the accuracy of which Mr. W. 
admits, designed to show the advantages and disadvantages 
of the present methods of illuminating transparent objects. 
The explanations which accompanied them I considered only 
to be of secondary importance, and though they appeared to 
me the most probable, yet I was ready to renounce them if 
they should be shown to be incorrect, or if reasons more pro- 
bable should be advanced. Now in both these points Mr. W. 
has in my opinion failed, for on a most careful perusal of his 
paper I am unable to discover that he has either proved my 
explanations to be in any respect untrue, or advanced more 
feasible ones in their place. 

As the explanation I have given of the cause of certain 
appearances presented by the Plewrosigma angulatum, under 
a particular kind of illumination, is merely the application of 
an optical fact, I see no reason for changing this opinion until 
it is shown either that I have misapplied this fact, or that 
what I have taken to be a universal law is not so. If I 
understand Mr. Wenham aright, he seems to me to deny the 
universal application of this law, “ stating that light when 
incident at any degree of obliquity on diaphanous refracting 
bodies, with parallel sides, cannot be made to suffer total 
reflection either externally or internally.” Now, as in this 
assertion there is so much ambiguity and complexity, and as 
it differs so much from the simple manner in which I have 
always seen the law enunciated, I cannot give up that which 
is universally admitted as a fact for what I cannot clearly com- 
prehend, and therefore I must beg to retam my opinion until 
Mr. Wenham has made good this assertion. In the applica- 
tion I have made of the law in question parallelism or non- 
parallelism has nothing to do with the subject, as the reflec- 
tion referred to in my paper is supposed to be from one 
surface only, namely, from that on which the rays are incident, 
I am well aware that all refracting bodies are too thick to 
have only one surface, but this forms no reason for compli- 


286 MEMORANDA. 


cating the enunciation of the law, the refraction or reflection 
taking place at each surface, requiring only a separate and 
independent observation. | However, if Mr. Wenham can 
prove by experiment that this fact is not universal I will give 
up my point, and in the mean time I am curious to know what 
the relation of the angle of incidence will be found to be to 
the angle of refraction, in the case of light passing from a , 
denser into a rarer medium, after the complement of the angle 
of refraction has vanished. : 

Mr. Wenham next observes that “ attempts have sometimes 
been made to draw the undulatory theory of light imto the 
subject of microscopic illumination, but without any substan- 
tial reason, as it has in reality very little or nothing to do with 
it.” By this assertion, which is sufficiently dogmatical, I 
understand that the author means that the undulatory theory 
may have a little to do with microscopic illumination, but 
that, in fact, that little is so very inconsiderable as to deserve 
to be looked upon as nothing. Now this assertion cannot be 
correct, for as at present there are only two ways known of 
accounting for the phenomena of light, and these so dissimilar 
that if one be right the other is wrong. Hence, if the undu- 
latory hypothesis be the correct one, it must apply as well to 
the facts connected with illumination as to the general facts 
of optics, and therefore if it apply in one instance to micro- 
scopic illumination, though in the least possible degree which 
Mr. Wenham ‘seems to alent it must be equally applicable 
to all. 

With respect to Mr. Wenham’s comments upon the globules 
of mercury, where he states that “he does not consider that a 
globule of this substance, as being strictly opaque is at all 
suited for testing an illumination intended» fdr transparent 
objects,” I may observe that this remark is unnecessary, as 
Mr. Wenham must have seen that these globules were never 
intended by me as a test of an illumination suited for trans- 
parent objects, but were merely employed to show some of 
the disadvantages of condensers, which purpose they answer 
extremely well by enabling us to illustrate a fact, which to 
my knowlege was not before demonstrated, namely, that in 
lenses of a short focus a great portion of the rays emanating 
from the source of light is reflected upon the object by the 
lenses composing the object-glass. Now these bodies being 
in all respects well adapted for illustrating and establishing 
this fact, and that in the most simple way, were I think very 
properly employed. But I did not stop here, the same effect 
was shown in my paper to be produced by transparent objects, 
though less in degree, that depending upon their form and 


MEMORANDA. 287 


density, and thus in the latter objects the light transmitted 
through them was shown to blend with that which they reflect, 
and so to produce a degree of confusion which, I maintained, 
ought to be taken intolaccount, and allowed for, as far as possible, 
in the examination of all transparent objects. 

This blending of transmitted and reflected rays, proceeding 
from the source of light, is greater when condensers are used 
than when only a plane mirror is employed, and therefore 
will be considered, I have no doubt, by all excepting Mr. 
Wenham, as an objection to these instruments, though, this 
being known and duly allowed for, the objection will be but 
trifling, Mr. Wenham says, “‘ he cannot call to mind any 
ordinary object in which the reflection alluded to above takes 
place to such an extent as to create false appearances.” If 
Mr. W. will take the trouble to look at globules of air in 
glycerine, illuminated by means of his own instrument, he 
will see it for the first time. These globules thus circum- 
stanced have certainly a most unnatural appearance, and 
would never be taken to be globules of atmospheric air. All 
other bodies partaking of the spherical form when examined 
ina fluid of a different refractive power, will exhibit the 
same fact. Oil globules in glycerine do not show it, but in 
water they do. See my paper. Lastly, Mr. Wenham objects 
to the employment of globules of mercury as a means of dis- 
proving the radiated light theory, stating “ that he does not 
see that it all affects the question, simply because it is one of 
those few substances that is incapable of radiating light.” 
In reference to this part, I may observe that these objects 
were not employed with the positive intention suggested in 
this remark, but were simply referred to as a satisfactory 
means of showing that all the appearances attributed by Mr. 
Wenham to radiated light are explicable on the common 
principles of reflection, and thus I consider that they have an 
important bearing upon the question ; for it must be admitted 
that if these facts allow of an easy and obvious explanation 
upon long-established principles, there can be no necessity 
to invent new theories to explain them, 

When I first became acquainted with Mr. Wenham’s con- 
denser, which I acknowledge to be a very beautiful instru- 
ment, whose utility will sathan be enhanced than abridged by 
any observations which I have-made upon its mode of action, 
and when I first read his paper upon its use and construction, 
I was in favour of his hypothesis, and of the term ‘ radiated 
light,” chiefly because the facts are so represented in his 
paper as to leave no other way of accounting for them, but on 
finding that all these facts admitted of an easy explanation 


288 MEMORANDA. 


upon well-known principles, | renounced his theory of radiated 
light, and if I can judge anything from a note in Mr. Wen- 
ham’s last paper, in which he evinces great dissatisfaction 
with the term “ radiated light,” as “not being perhaps philo- 
sophically correct,” I am strongly of opinion that he either 
has or soon will follow my example.—Gerorcre Rarney, Sf. 
Thomas's Hospital. 


Whe Spiral Wessel of Rhubarb, as seen under the influence 
of Polarized Light.—I have, in my possession, a specimen 
of the spiral vessel of the rhubarb, given to me by a friend, 
but although I have viewed it with a low power of great ex- 
cellence (Smith and Beck’s 2-d3rd), yet I have never been able 
to see it satisfactorily with clearness and precision. This 
induced me to look at it with the polarizing apparatus, and 
when the Nichol’s prisms are turned so as entirely to darken 
the field, I was much pleased to see the spiral vessel beauti- 
fully iluminated and the spiral perfectly distinct. I was 
induced to try a “ selenite stage,” in which the tints are violet 
and yellow in the alternate quarter revolutions of the polarizer, 
and the effect was not only exceedingly beautiful, but also very 
instructive, as the spiral exhibits, when the field is deep blue 
or violet-coloured, a most beautiful crimson, and is very 
clearly distinguishable from the investing membrane, thus 
affording an example of the utility of polarized light in cer- 
tain circumstances. —G., Hunt, Birmingham. 


List of Diatomacee-—The following Diatomacez were dis- 
covered in the recent United States Exploring Expedition, 
under Capt. Wilkes. The list here given is in the order of 
their geographical distribution. 


Puget’s Sound, Oregon. 


DIATOMACEA. 


Isthmia obliquata. 

Rhabdonema arcuatum, Kiitz. 
Surirella fastuosa, Ehr. 
*Triceratium Wilkesii, H. et B. 


Actinoptychus senarius, Ehr. 
* Aulacodiscus Oreganus, H. et B. 
* Amphitetras Wilkesii, H. et B. 
Arachnodiscus Ehrenbergii, Bailey. 
*Cocconeis rhombifera, H. et B, 

aA sulcata, H. et B. 
Coscinodiscus oculus-iridis, Ehr. 
radiatus, ¥ 
excentricus, mn 


Spongiolites, &c. 


Spongiolites Agaricus, Ehr. 
Dictyocha splendens, Ehr. This is 


> 


Epithemia g gibberula, Kiitz. 

Grammatophora angulosa, Ehr. 
Be stricta, 1 
Y. undulosa, ,, 


now known to be a calcareous 
plate from a species of Synapta. 
It dissolves in acids, and polarizes 
light. 


MEMORANDA. 289 


San Francisco, California. 


Arachnoidiscus Ehrenbergii, Bail. Gomphonema minutissimum, Ehr. 
Cocconeis scutellum, Ehr. 


Terra del Fuego. 


Entopyla australis, Ehr. Grammatophora stricta, Ehr. 
Grammatophora serpentina, Ehr. 


Rio Janeiro. 


Climacosphenia australis, Kutz. Spongiolites anchora, Ehr. 
Grammatophora oceanica, Ehr. The last two come from the cal- 
*Isthmia minima, H. et B, careous particles of an Echino- 
Dictyocha splendens, Ehr. derm (Synapta). 

Valparaiso, 
Stauroptera aspera, Ehr. Gallionella sulcata, Ehr. 
Cocconeis scutellum, ,, Grammatophora hamata, Ehr. 
Actinoptychus senarius, Ehr. Dictyocha speculum, Fi 


Philippine Islands. 


*Amphitetras favosa, H. et B. | Navicula Lyra, Ehr. 

Amphora libyca, Ehr. Pinnularia didyma, Ehr. 
*Campylodiscus Kiitzingii, H.et B. | Surirella fastuosa, Ehr. 
Coscinodiscus linearis, Ehr. Tetragramma asiatica, Ehr. 
Denticella Biddulphia, ,, *Triceratium orientale, H. et B. 
Gallionella sulcata, - Dictyocha splendens. 
Grammatophora oceanica, Ehr. Spongiolites Agaricus. 

Navicula elongata, - 


Sooloo Sea. 


Coscinodiscus excentricus, Ehr. Triceratium Favus, 8. acuminatus, 
Ps marginatus, ,, Bail. 

Gallionella sulcata, ‘a Spongiolites Agaricus, Ehr, In situ, 

Grammatophora oceanica, ,, forming bunches in the tissue of 

*Isthmia minima, H. et B. | a sponge. 


Surirella fastuosa, Ehr. 
Wilson’s Island. 


PoumouTa GROUP. 


Climacosphenia australis, Kiitz. Stauroptera aspera, Ehr. 
Podocystis adriatica, es Pinnularia didyma, ,, 
Tahiti. 

Climacospheenia australis, Kiitz. Navicula Sigma, Ehr. 
*Cocconeis Parmula, H. et B. Podocystis adriatica, Kiitz. 
Denticella Biddulphia ? Ehr. Stauroptera aspera, Ehr. 
Grammatophora oceanica, Ehr. Triceratium concavum, H. et. B. 
Gallionella sulcata, a Epithemia musculus, Kiitz. 
*Hyalosira punctata, H. et B. 

Tongataboo. 
Denticella Biddulphia? Ehr. Grammatophora oceanica, Ehr. 
Epithemia musculus, Kiitz. Synedra superba, Kiitz. 


VOL, II, x 


290 MEMORANDA. 


New Zealand. 


A large collection of marine Alga from New Zealand was examined, but 
n0 Diatomacex could be detected adhering to them. 


Those marked thus (*) are believed to be new, and have been described. 
—Professor J. W. Batney, in Proceedings of the Academy of Natural 
Sciences of Philadelphia, Oct., 1853. 


Mateh Photographs, or Camera Eucida drawings of Mi- 
eroscopic Objects for the Stereoscope, made by means of 
the ordinary Monocular Microscope.—Professor Wheatstone, 
the eminent physicist, in connexion with his remarks upon 
the value of the binocular microscope, in the July number of 
the ‘ London Microscopical Journal,’ suggests that the mono- 
cular microscope may be made to give match stereoscopic 
pictures, by successively changing the inclination of the axis 
of the objective and ocular to the stage holding the object. 
This plan, though not easily made applicable to microscopes 
of the present construction, must, | think, give excellent 
results with the low powers, say with the two inch and inch 
objectives, and possibly with the half inch. But with the 
higher powers of large angle of aperture, the close proximity 
of the front surface of the objective to the thin glass cover of 
the objects totally precludes its being put in practice. 

The method described below may be readily adapted to any 
microscope, at an expense comparatively trifling ; it is appli- 
cable to every grade of objective ; and upon fair trial I find it 
to give satisfactory results. 

Behind, and close to the objective, insert an isosceles glass 
prism, say a half or a quarter inch equilateral or rectangular 
prism, adjustable for position, and capable of being inclined 
at pleasure any required number of degrees, on a central axis 
transverse to the axis of the ocular and objective, said axis 
being parallel to the polished faces of the prism. When the 
hypothenuse or reflecting surface of the prism is made coin- 
cident in direction with the axis of the microscope, the posi- 
tion of the prism being appropriate, the light travelling from 
the objective to the ocular will suffer reflection in its transit 
through the prism; but the appearance and position of the 
field, except its reversal in one direction, will be essentially 
the same as if no prism were there. By inclining the prism a 
little, other objects are brought into view, as though the slide 
containing them were moved. If now, the slide be re-adjusted, 
so as to restore the field as at first, the objects will be seen 
from a different point of view, and will therefore wear a modi- 
fied appearance. : 

The mode of proceeding is as follows: two good successive 


MEMORANDA. 291 


views of the same object are to be obtained, between which 
there must be a difference of inclination of the prism, say 
from four to eight or nine degrees, according to the depth of 
stereoscopy desired, In each instance, the principal object is 
brought to the centre of the field, by adjusting the position of 
the slide. In each instance, a careful camera lucida drawing 
is to be made, or a photographic impression taken; which, 
when properly viewed, each by an eye, will be found to 
coalesce into a single image, manifesting the fine stereoscopic 
effect, which characterizes the image seen through the bino- 
cular microscope.—Proféssor Rippett, New Orleans Medical 
and Surgical Journal. 


On the use of the Camera lucida as a Micrometer.—Several 
communications on micrometers have appeared in the ‘ Micro- 
scopical Journal,’ and | am induced to address you on the sub- 
ject from having particularly noticed the two following extracts 
of a letter from. Mr. Jackson in your last Number :— 

“ The inquiries for a cheap form of microscope which I 
constantly hear, make me think that the difference between Al. 
and 1/. for an adjunct to the instruments, would, in many in- 
stances, be a serious obstacle to the use of any means of minute 
measurement; and it is with the view of placing these means 
within the reach of all observers that I have advocated ruled 
glass. 

“To induce observers to make accurate measurements, 
which is the aim both of H.C. K. and myself, it is not suffi- 
cient to place an instrument in their hands; they must be 
taught to use it with little trouble.” 

1 think that the following method of using the camera 
lucida with a stage micrometer answers the requisites of 
cheapness, facility, and accuracy :— 

Place a stage micrometer in the focus of a microscope ; 
adapt a camera lucida, and then accurately trace on a piece of 
card-board, one, two, three, or more of the divisions. Subdi- 
vide each division by tens or (if need be) by hundreds ; then 
place the object to be measured in the focus of the microscope, 
and observe, through the camera lucida, the number of divi- 
sions it extends over on the card-board. For instance: I have 
an object-glass and eye-piece which, with the length of tube 
in my microscope, magnify 500 diameters ; and on looking 
with these at a stage micrometer, with 200 divisions to the 
inch, I find that each division occupies 24 inches on a card- 
board placed underneath the camera lucida on the table, I 
mark one of these spaces on the card-board, and divide it into 
25 parts; that is, into tenths of an inch, and, consequently, 


292 MEMORANDA. 


each tenth of an inch on the card-board corresponds to the 
5000th part of an inch of an object in the focus of the 
microscope. Obviously, also, if instead of card-board, I use 
a slip of ruled glass, with a hundred divisions to the inch, 
each division will then correspond to the 50,000th part of an 
inch. 

For convenience of calculation, it is desirable that each 
division of the micrometer should coincide with the lines of 
inches, or large fractional parts of an inch, on the card-board ; 
and this is easily effected when the microscope is furnished with 
a draw-tube ; but when the latter is wanting, the same point 
may be gained by elevating the card-board on a book or some 
kind of stage; of course, always taking care that the distance 
of the camera lucida from the card-board should be precisely 
the same, when an object is to be measured, as it was when 
the divisions were marked on the card-board. The ease of 
this method, also, in, accurately determining the magnifying 
power of any combination of lenses and eye-pieces he may 
happen to possess, will be evident to any one attempting to 
practise it. The cost of a camera lucida is very trifling, and 
there would be no need to purchase a stage micrometer, if one 
could be borrowed for a short time, since a piece of card-board, 
once accurately marked* in the above manner, would supersede 
its further use-—HENRY CoLEs, Hammersmith. 


. * For each power.—[Eb. ] 


( 293) 
PROCEEDINGS OF SOCIETIES. 


Microscoricayt Society. May 17th, 1854. 
Dr. Carpenter, President, in the Chair. 

J. F. Streatfield, Esq.; J. Lubbock, Esq.; — Shelly, Esq. ; 
Dr. T. J. Sturt; A. Mongredieu, Esq. ; and J. G. Noble, Esq.,— 
were elected Members of the Society. 

A paper on the Circulation in Closterium Lunula, by the Rev. 
S. G. Osborne (see Journal, p. 234) was read. 


March 29th, 1854. 
Dr. Carpenter, in the Chair. 

James M‘Mahon, Esq.; Andrew Yeates, Esq.; Antonio Brady 
Esq.; C. O. Dayman, Esq; and George Hanby, Esq.,—were, 
balloted for, and duly elected. 

A paper by Mr. Jabez Hogg, on the development and growth of 
the Water-snail, was read (Transactions, p. 9!). 


April 19th, 1854. 
Geo. Shadbolt, Esq., in the Chair. 
R. W. 8S. Lutwidge, Esq., and James Townley, Esq.,—were 
balloted for, and duly elected. 
A paper by Dr. W. Gregory, of Edinburgh, on some deposits of 
Fossil Diatomacez, was read (‘Transactions, p. 104). 


Roya Society. March 9th, 1854. 
On a new and more correct Method of determining the Angle of 
Aperture of Microscopie Object-Glasses. By W.S. Gruuert, 
M.A. 


Tue author began:—‘ With the consideration that the central 
pencil was alone to be regarded, and that the marginal rays of this 
were the true limits of the angle of aperture, and that consequently 
the rays of all oblique pencils were to be excluded, as these might 
cross at a point not coincident with the principal focus, and being 
measured separately, might form an angle (apparently of aperture) 
not coinciding of course with the true one, although perhaps not 
differing from it in amount.” Mr. Gillett’s mode of measuring the 
aperture is as follows :—‘* The microscope is placed horizontally, 
and centred by an object placed in the focus. A hollow cone is 
substituted in place of the eye-piece, having an aperture at its 
summit. Light passing through this aperture is made to form an 
image of it in the principal focus of the object-glass, in the place 
of the original object. On this image a horizontally-placed ex- 
amining microscope is then directed, which traverses as the radius 
of a graduated circle, having its centre corresponding with the 
plan of the original object, and therefore with the image to be 
received ; and the angle of aperture is measured by the are passed 
through between two extreme positions in the usual manner.” 


294 PROCEEDINGS OF SOCIETIES. 


May \\th, 1854. 


On the relation of the Angular Aperture of the Olject- Glasses 
of Compound Microscopes to their penetrating power and to 
oblique light. By J. W. Grirrita, M.D. 


Dr. Griffith’s remarks had reference only to transparent objects. 

The ordinary cause of the outlines of objects becoming visible 
consists in the refraction of the light out of the field of the micro- 
scope, or beyond the angle of aperture of the object-glass; and 
another condition affecting distinctness consists in the relation which 
the luminousness or darkness of an object bears to that of the field 
or background upon which it is apparently situated. An increase 
of the angular aperture of the object-glass in certain cases will there- 
fore impair the distinctness of their images, because this increased 
aperture will allow of the admission of those rays which would 
otherwise have been refracted from the field, and the margins will 
become more luminous and less contrasted with the luminous field. 

If the parts of an object which refract light are large in propor- 
tion to the power of the-object-glass and of irregular form, they will 
refract a certain number of rays, so that these cinnot enter the 
object-glass ; hence certain parts will become dark, and will map 
out in the image the structural peculiarities of the object. But. if 
the parts are minute, of a curved form and nearly symmetrical, they 
will act upon the light transtitted through them in the manner of 
lenses, and their luminous or dark appearance will vary according 
to the relation of the foci of these guasi lenses to that of the object- 
glass. 

In certain objects, however, of extreme minuteness, such as the 
valve of a Gyrosigma (Pleurosigma), the irregularities of struc- 
ture are so very inconsiderable, or the difference of the refractive 
power of the various portions of the structure is so slight, that the 
course of the rays is but little altered by refraction on passing 
through them, and under ordinary iliumination all the rays will 
enter the object-glass ; neither are the rays collected into little cones 
or parcels of sufficient intensity to map out the light or dark spots 
in the field of the microscope, according to the relation of their 
foci with that of the object-glass. 

This is the case with light transmitted directly through the object 
as in the ordinary mode of illumination ; but when oblique light is 
transmitted, one of the two sets of rays passing through the de- 
pressed and the undepressed portions of the object will be so refracted 
as not to enter the object-glass, whilst the other set will gain admis- 
sion, and thus the two parts will be rendered distinct. If the 
markings are more delicate, or if the difference between the refrac- 
tive power of the two portions of the object is less, both sets will 
enter the object-glass. But when the light is rendered still more 
oblique, oue set would be again excluded being refracted out of the 
field. Henceit is evident that the angular aperture must be larger 
as the markings are finer, or the difference between the refractive 
power of the portions of the tissue is less; because the obliquity of 


PROCEEDINGS OF SOCIETIES. 295 


the light will be required to be very great to cause the exclusion of 
one set of the rays, and the other set would necessarily be too 
oblique to enter the object-glass unless it be of correspondingly large 
aperture. 

The author then proceeds to explain the reason why a central 
stop will in certain cases render delicate markings more distinct, by 
stopping off the more direct rays, and allowing only the oblique 
ones admissible into an object-glass of large aperture to enter it. 
The direct rays, in fact, not conducing in any way to the more 
distinct perception of the object, the image of which is formed, as 
above explained, by what may be termed the difference between the 
more and the less refracted rays. And the difficulty in explaining 
how an object-glass of large angular aperture will*render markings 
evident which were not visible under an object-glass of smaller aper- 
ture, vanishes when it is considered that the additional rays admitted 
by the object-glass of larger aperture are more oblique ; hence one 
set of rays, as in the above case of oblique light, will be refracted 
from the field of the microscope, whilst the other set will enter it. 
Now as it is these additional rays alone which render the delicate 
markings evident, it is obvious that the more direct central rays 
(being at any rate useless) can only serve to impair the distinctness 
of the image, and that advantage will arise from cutting them off 
by a central stop. 

The paper then proceeds to discuss the relation of the penetrating 
power of an objective to its defining power. The author’s defini- 
tion of what he terms penetrating power ; would appear to make it 
depend upon the amount of angular aperture, but it is not very 
clear what is meant by defining power as contradistinguished from 
the above, or from the power of giving a clear definition of objects— 
a quality obviosuly dependent simply upon the accuracy with which 
the chromatic and spherical aberration of the objective are cor- 
rected, and wholly independent of magnifying or separating power. 


Royau Intsh AcApemy. January 23rd, 1854. 


On a New Method of measuring the Angular Aperture of the 
Objectives of Microscopes. By the Rev. T. R. Roxsrnson, D.D., 
President of the Royal Irish Academy. 


Tue effect of angular aperture is stated to be merely an increase of 
illuminating power analagous to that of linear aperture in a tele- 
scope, and from mathematical considerations given in the paper, 
it appears clear that, especially for covered objects, nothing is gained 
above 150° at all commensurate to the difficulty of constructing 
such objectives. ‘‘ But in addition to this,” the author goes on to 
say, “‘ that the whole of these great apertures is not in every case 
thoroughly effective.” 

This made him seek some mode of measurement which would 
not only give the angle of aperture, but also show how the light 
was distributed; and the following seemed to fulfil both these 
requirements :— 


296 PROCEEDINGS OF SOCIETIES. 


“ As a lucid point in the focus of the objective sends out from 
[to] the eye-piece rays nearly parallel, so light, sent in the opposite 
direction through the microscope, will converge at that focus and 
diverge in a cone whose angle equals the aperture of the objective. 
If this cone be intercepted at right angles to its axis by a screen, 
and the diameter of its section, together with the distance of the 
sereen from the surface of the objective be carefully measured, they 
give the aperture. If S be the diameter of the section, D the 
distance, O the diameter of the objective, and I that of the image of 
the luminary used which is formed in its focus :— 

2 tan. A ore x aie 
2 D O+! 
the upper sign being used if the section is measured within the 
penumbra and vice versd. In most cases, I will be so small that the 
second factor is — unity; for the author directed the light of 
the sun into the instrument by means of the reflecting part of a 
solar microscope, and not only got measures with extreme facility, 
but had at once a beautiful map of the objectives light-territory. 

The results of measurements of available aperture taken in this 
way as compared with those by the usual method were briefly as 
follows, and from which the importance of this mode of examining 
stated apertures of object-glasses, will be at once apparent :— 


Aperture. 
Focal length By By 
of Objective. New Method. Old Method. 
No. 1 + 80°.8 80°.75 

ee vb 110°.8 160°.0 
ae a5 109°.3 129°.0 
sn fat Gb 102°.0 126°.4 
5 ae 15 114°.6 156°.0 
as) ~ 122°.8 170°.0 


The facts adduced are sufficient, as the author believes, to show 
the necessity of attending not merely to the amount of aperture but 
also to its quality. What is the cause in the deficiencies in the 
latter respect can be determined only by one familiar with the con- 
struction of the objectives, but it probably arises from some of the 
lenses being so small that their edges meet the luminous pencil and 
reflect false light. The disturbance, however, may also be owing 
to the brass of the cells, but if so the remedy is the same, viz., the 
increasing a little the diameter of the posterior lenses. The author 
would also suggest another alteration, in case it be thought desirable 
still to make objectives of these extreme apertures—that the anterior 
surface be concave instead of plane. 


. 
i 


TRANSACTIONS OF MICROSCOPICAL SOCIETY. 


DESCRIPTION OF PLATE VII. 


To illustrate Mr. Hogg’s Paper on the Development and Growth 
of the Water-snail. 


Fig. 
1.—A magnified representation of the increase and change of situation 
occurring to the yolk of egg of Limneus on the fourth day. 


2.—The change observed on the sixth day, showing the transverse fissure 
or divisional line in the mass. 


3.—The formation of the shell proceeding more rapidly, it appears on the 
sixteenth day as the larger portion of the embryonic mass. 


4,.—The embryo performing its heliacal windings around the shell. 


5.—The embryo, or young animal, seen soon after it has issued from the 
shell. 


6,—The tentacles, with cilia, seen under a 34-inch object-glass ; the arrows 
indicating the course of the current produced by the cilia. 


7.—The natural size and form of the shell of a full-grown Limneus. 


8.—Parasitic animal found on the body of Limneus, magnified 100 
diameters. 


MW 


Py 
£ Ge 


DE/ TTC 
OC. atl 


4 
ALG 


5 


SS ee Mon 


JOURNAL OF MICROSCOPICAL SCIENCE. 


DESCRIPTION OF PLATE IX. 


In illustration of Mr. Currey’s Paper on two new Fungi. 
Fig. 
1 and 2.—Natural size of one of the Fungi. 
3 and 4,—The same magnified by a 2-inch object-glass. 
5.—The capillitium and spores under a 4-inch object-glass. 
6 and 7.—Natural size of second Fungus. 


8.—Spores and hairs in its interior under a power of 220 diameters. 


Valen West. chromy ith 


TRANSACTIONS 


OF THE 


MICROSCOPICAL SOCIETY 


LONDON. 


NEW SERIES. 


VOLUME II. 


LONDON: 
SAMUEL HIGHLEY, 32, FLEET STRERT. 
1854. 


aay Loe ay. Oy | 


INDEX TO TRANSACTIONS. 


VOLUME IL 


A. 


Actinophrys Sol, remarks on, 


by 
R. S. Boswell, 25. 


3p 


Binocular vision, on the application | 
of to the microscope, by F. H. Wen- | 


ham, 1. 

Boswell, R. 8., remarks on Actino- 
phrys Sol, 25. 

Busk, G., F.R.S., on the structure 
and function of the avicularian 
and vibracular organs of the Poly- 
Zoa, 26. a 


Diatomaceex, new forms of, from Port 
Natal, description of, by G. Shad- 
bolt, 13. 

. of the Thames, some 
observations on, by F. C. 8. Roper, 
F.G.S., 67. 

He 


Hogg, Jabez, observations on the 
development and growth of the 
Water Snail (Limneus stagnalis), 
91. 


I. 


Illumination of transparent objects, 
on a method of employing artificial 
light for, by G. Rainey, M.R.CS., 
23. 


L. 


Legg, M. S., A.I.A., observations on 
the examination of Sponge-sand, 
1S: 

Limneus stagnalis observations on 
the development and growth of 
the, by Jabez Hogg, M.R.C.S., 91. 


M. 


Microscopical Society, Report of the 


Fourteenth Annual Meeting of the, | 


81. _ 


PB 


Polyzoa, remarks on avicularian and 
vibracular organs of, by G. Busk, 
F.R.S., 26. 


Q. 


Quekett, John, on the minute struc- 
ture of the Torbane Hill mineral, 
34, 


R. 


Rainey, G., M.R.C.S., on a method 
of employing artificial light for the 
illumination of transparent objects, 
23. 

Report of the Fourteenth Annual 
Meeting of the Microscopical So- 
ciety, 81. 

Roper, F. C. S., some observations on 
the Diatomaceze of the Thames, 67. 


S. 


Shadbolt, G., description of some new 
forms of Diatomaceze from Port 
Natal, 13. 

Sponge-sand, observations on the ex- 
amination of, &c., by M.S. Legg, 
AXTCAS, 19: 


dhe 


Torbane Hill mineral, or Boghead 
coal, on the minute structure of, by 
John Qnekeit, 34. 


We 


Water Snail (Limneus Stagnalis), J. 
Hogg, on the development and 
growth of the, 91. 

Wenham, F. H., on the application of 
binocular vision to the microscope, 
1. 


TRANSACTIONS 


OF THE 


MICROSCOPICAL SOCIETY 


OF 


LONDON. 


On the Application of Binocutar Vision to the Microscope. By 
F. H. Wennam. (Read May 25, 1853.) 


On viewing objects by the unassisted eyesight there are two 
conditions which enable us to appreciate or judge their various 
distances. Firstly, the object is observed by each eye from 
a separate point of view, and the consequent difference of 
outline, light, and shade between the images formed on each 
retina allows us to form an accurate idea of their various 
sizes and positions. ‘The angle of stereoscopic vision has been 
stated somewhat definitely to be about 18 degrees, but this 
must be subject to considerable variations, as whether the ob- 
server is long or short-sighted, the difference of distance 
between the eyes, and also the bulk, form, and position of the 
object. I may state that I have obtained a very good perspec- 
tive of minute objects when the angle of vision has exceeded 
50 degrees, 

If we perforate a card with a pin, and examine the articles 
in a room illuminated by candle-light, with one eye looking 
through this aperture, we shall be able to judge of distance 
only from the relative intensity with which the objects are 
illuminated, the nearest receiving and giving off the greatest 
quantity of light, and the farthest being in comparative darkness, 

I make these preliminary observations because, in viewing 
the greatest portion of objects under the microscope, the con- 
ditions here referred to, which give us the faculty of judging 
of bulk and distance, do not exist in the same degree, if at 
all. In the first place, in viewing an object, as a transparency, 
with a single lens of short focus, we see it under such circum- 
stances as seldom happen to such surrounding objects as come 
under our daily observation, and in the illumination of trans- 
parent objects by direct transmitted light, the effect is the 
reverse of that which is necessary for us to judge of distance 

VOL. 11, 


B WenuaM on Binocular Vision. 


by the relative intensity of the light, for that portion of the 
object farthest from the lens will receive the greatest share. 
This objection may probably be removed by a different sys- 
tem of illumination, but of this I shall treat hereafter. If the 
single lens is provided with a proper stop, what is known as 
the angle of aperture will be so exceedingly small that a series 
of uniform opaque particles lying behind each other in an 
object will be only seen by the direct light that they intercept, 
and the underlying: ones will be invisible. These are the 
reasons why most microscopic objects, which we know must 
have a visible thickness, appear so perfectly thin, that we 
might almost imagine that they were painted on the glass 
slide upon which they are mounted. This illusion. may be 
attributed to the natural effects of monocular vision, and in 
this case the only remedy is to view the object from different 
points at the same time with each eye, under equal magnify- 
ing power. I shall now enter into various methods of effect- 
ing this. One of the most simple and obvious is to employ 
two lenses, one to each eye, only differing from an ordinary 
pair of spectacles in the foci being shorter and the optic axes 
converging till the points where the foci intersect become 
coincident. 

Binocular vision may also be obtained through a single 
lens, if the diameter is sufficiently large to allow both eyes to 
see through it at the same time as in the common reading- 
glass. In these instances we cannot well use glasses of shorter 
focus than four or five inches; and in cases where higher 
magnifying powers are required it becomes necessary to adopt 
some method which shall produce the effect of bringing the 
two eyes proportionately closer together, to suit the diminished 
diameter and shorter focus of the lens. This may be accom- 
plished by means of a system of four plane reflectors, inclined 
at an angle of 45 degrees, and fixed behind the lens in a 
line at right angles to its axis, or else by four rectangular 
prisms in the same position; both these can be made 
to adjust to suit the 
diameters of various 
lenses and difference of 
distance between the 
eyes. 

The arrangement that 
I have tried for lenses 
of short focus is repre- 
sented by fig. 1: a@a@ is 
a plano-convex lens, be- 
hind which is placed the usual stop db. _¢ ¢ are two rhomboidal 


Fig. 1. 


Wenuam on Binocular Vision. 3 


prisms of glass, with the reflecting ends inclined at an angle 
of 45 degrees. All the four surfaces of both prisms should 
be well polished, and their combined length when placed 
together should be such that the distance between the centres 
of the external diagonal reflecting planes should be the same 
as that between the eyes. I prefer the two solid prisms to a 
combination of four rectangular ones, as there is less loss of 
light, and error arising from external reflection. This com- 
bination makes a remarkably fine hand magnifier, giving such 
a depth and substance to objects as cannot be obtained with a 
single eye; the field of view is also large, as we are able to 
see the object obliquely through the lens. For lenses of low 
power, as from one to two inches focus, the prisms would 
require to be separated to some extent, or we should not ob- 
tain a sufficient angle for stereoscopic vision; in fact, we 
must consider this merely as a method of bringing the eyes 
closer together, that we may be enabled to see through a lens 
of small diameter with both of them at the same time, ina 
similar way as with the ordinary reading-glass before re- 
ferred to. 

On looking through the prisms, fig. 1, without the magni- 
fier, a singular illusion is produced, for the vision with the 
two eyes is brought so nearly to a state of parallelism that 
they are in effect blended into one, and we so far lose the 
power of appreciating distance, that we appear able to grasp 
objects several feet away from us, as the deceptions arising 
from monocular vision are increased by seeing with the two 
eyes from the same position as with one. 

In obtaining binocular vision with the compound achromatic 
microscope, in its complete acting state, there are far greater 
practical difficulties to contend against, and which it is highly 
important to overcome, in order to correct some of the false 
appearances, arising from what is considered the very perfec- 
tion of the instrument. All the object-glasses from the one 
inch upwards are possessed of considerable angular aperture, 
consequently images of the object are obtained from a differ- 
ent point of view, with the two opposite extremes of the 
margin of the cone of rays; and the resulting effect is, that 
there are a number of dissimilar perspectives of the object, all 
blended together upon the single retina at once. For this 
reason, if the object has any considerable bulk, we shall have 
a more accurate notion of its form by reducing the aperture of 
the object-glass, 

Select any object lying in an inclined position, and place it 
in the centre of the field of view of the microscope, then, 
with a card held close to the object-glass, stop off alternately 

b2 


4 WENHAM on Binocular Vision. 


the right or left hand portion of the front lens, it will be seen 
that, during each alternate change, certain parts of the object 
will alter in their rela- 
tive position. To il- 
lustrate this, figs. 2 
and 3 are enlarged 
drawings of a portion 
of the egg of the com- 
mon bed-bug (Cimex 
lecticularis), the oper- 
culum which covers the 
orifice having been 
forced off at the time 
the young was hatched. The figures exactly represent the 
two positions that the inclined orifice will occupy when the 
right and left hand portions of the object-glass are stopped 
off. It was illuminated as an opaque object, and drawn 
under a two-thirds object-glass of about 28° of aperture. 

If this experiment is repeated, by holding the card over 
the eye-piece, and stopping off alternately the right and left 
half of the ultimate emergent pencil, exactly the same changes 
and appearances will be observed in the object under view. 
The two different images thus produced are just such as are 
required for obtaining stereoscopic vision. It is therefore 
evident, that if, instead of bringing them confusedly together 
into one eye, we can separate them, so as to bring figs. 2 and 
3 into the left and right eye, in the combined effect of the two 
projections we shall obtain all that is necessary to enable us 
to form a correct judgment of the solidity and distances of the 
various parts of the object. 

I shall now explain some plans for effecting this. The 
most obvious method is to have two microscopes placed side 
by side, and converging towards the object, each tube to be 
furnished with a similar objective and eye-piece. For very 
low powers this would, no doubt, be the most perfect form of 
binocular microscope, but it is liable to objection, firstly, on 
account of its expense, and, secondly, from the difficulty, if 
not impossibility, of using the higher powers. I do not think 
that it would be practicable to use anything beyond the half- 
inch object-glass; but I believe where vision is assisted by 
the use of both eyes together, it would be of advantage to 
employ objectives of smaller angular aperture, in this case, the 
focus would then fall at a greater distance from the front lens, 
I should also mention that a microscope of this description 
would require the two tubes to be placed at a different angle 
of convergence for every pair of object-glasses employed, of 
either longer or shorter focus. 


~ 


WenuaM on Binocular Vision. 5 


It has also been proposed to bisect the whole combination, 
of which our best objectives are composed, and separate the 
semi-lenses a sufficient distance asunder to obtain the effect 
of stereoscopic vision, each half being made to serve the 
purpose of a distinct combination; but this, I believe, would 
not answer at all, for if we escaped the total destruction of 
the object-glass Rene the operation of sawing it through, we 
should render it aoe for all the ordinary purposes of inves- 
tigation, and also because any separation of the semi-lenses 
is quite unnecessary; for the angle of aperture of al! the 
object-glasses by our best makers now exceeds that which is 
requisite for obtaining stereoscopic vision; and the methods 
that I have now to explain refer to the principle of obtaining 
two images of the object through the same object-glass, which 
is in all cases of the usual construction. 

In the last ‘Quarterly Journal of Microscopical Science’ 
there appeared a notice of a binocular microscope by J. L. Rid- 
dell, from Silliman’s Journal. Fig. 4. 

According to his description, 
fig. 4 will represent the ar- 
rangement ; a is the objective 
provided at the back with the 
usual stops. The pencil of 
rays emergent from the ob- 
ject- glass is bisected and re- 
flected in opposite directions, 
by means of the internal 
surfaces of the rectangular 
prisms } b, which surfaces 
are inclined at an angle of 
45°, / The rays are again re- 
flected ina vertical direc tion, 
by means of two anti 
prisms, cc, the distance be- 
tween which must be regu- 
lated by the position of the 


eyes. The last prisms must KG 
be placed upon a lower level, ERR 


as from the direction in which 
the rays are incident upon 
the first reflecting surfaces of the prisms b b, they have a down- 
ward tendency. The rays, after crossing each other, are received 
by two Huygenian eye-pieces, dd. In the diagram I have 
shown the prisms no larger than necessary for collecting all 
the rays from any of the object-glasses to be used; but it 
must be evident that Mr. Riddell makes use of prisms of 


6 WenuAM on Binocular Vision. 


a larger size, as he states that “The outer prisms can be 
cemented to the inner by Canada balsam.” This amounts 
to the same thing as using a pair of prisms of solid glass, 
such as is represented by cc, fig. 1. I have carefully tried 
both of these methods, and find that the prisms alter the 
chromatic correction of the object-glass, and also materially 
injure the definition; for in making arrangements of prisms 
of this description we must always bear in mind that they 
produce a similar kind of aberration as a piece of glass of the 
same thickness as the distance which the ray passes through, 

Fic. 5. both before and after its reflection. ‘There 
is also great difficulty in getting a per- 
| fectly flat surface to the small reflecting 
planes. All these defects will be greatly 
magnified by the eye-piece. 

I have also tried what effect could be 
produced by means of plane reflectors, as 
Mr. Riddell says, “I use, for lightness 
and economy, four pieces of common 
looking-glass instead of prisms.” My 
experiment was not tried with common 
looking-glass, but with thin microscopic 
covering-glass, silvered at the back. The 
definition with the lower powers was to- 
lerably good, but the loss cf light very 
great. 

In order to remove the illusion of ele- 
vations appearing as depressions, Mr. 
Riddell proposes the “additional use of 
erecting eye-pieces ;” but I am afraid that 
when the microscope is taxed with this 
addition, the loss of light and defining 
power will become very great, and that 
even easy test-objects will appear so ob- 
scure as to preclude all hope of our 
making any additional discovery relative 
to their structure. 

I must remark, that I have made these 
last observations and experiments merely 
for the sake of arriving at the truth, and 
not with the view of detracting in the 
slightest degree from the merits of Mr. 
Riddell’s invention ; for very great credit 
is no doubt due to him for leading the 
way to the practical application of a principle, in the absence 
of which the microscope still remains an imperfect instru- 
ment; and, for my own part, I may, in all probability, shortly 


~l 


WenuAM on Binocular Vision. 


see the day when my own designs for effecting the same end 
may be rendered obsolete by the march of i improvement. 

In the plan just referred to, the error arising from the 
length or thickness of the prisms may 
be Seetoshed by making the two mi- 
pares bodies converge towards b J, 

3, and adopting two reétangular 
= with the reflecting surfaces at 
the proper inclination for directing the 
rays of light from the objec t-glass, up 
the centre of each tube: by this means 
we can much reduce the substance of 
glass that the rays will have to pass 
through. 

Figs. 5 and 6 represent another 
dicthud that I have contrived for using 
only two prisms, which can be made of 
the smallest possible size, and also at 
the same time do away with one re- 
flecting surface, which is one of the 
principal sources of error. Fig. 5 is 
“i plan, and fig. 6 the elevation. a, 

g. 6, is the object-glass, over which 
a8 two right-angled prisms bb, placed 
side by ide with the reflecting sur- 
faces, at an angle of 45°. ce, fig. 5, 
are two Huygenian eye-pieces, placed 
a sufficient distance asunder to suit 
the eyes, and converging towards the 
vertical axis of the object-glass. The 
contact sides of the prisms must be 
equally ground away, till their two 
emergent surfaces are in a plane at 
right angles to the axes of their respec- 
tive eye-pieces. This method in- 
volves the necessity of having the 
object-glass at right angles to the 
two bodies of the microscope, and is therefore just suited to 
some of the foreign form of stands, but is of course inap- 
plicable to the English ones, unless, indeed, we mount the 
bodies after our usual fashion, and allow the object-glass to 
point upwards in an inclined direction, and pass through the 
bottom of a stage, on the upper surface of which the objec ts 

can be placed, and which surface should be parallel to the 
axes of the bodies. This would give great facility for direct 
illumination; for whether we used a superposed ‘achromatic 
condenser or not, we should not require a mirror either by 


Fig. 6. 


8 WENHAM on Binocular Vision. 


day or candle-light. I have not yet tried this arrangement of 
prisms, but intend to do so, as I have a favourable opinion of 
the method, although the one next to be described is pro- 
bably better.. 

If we consider the relative position of the two reflecting 
surfaces of the prisms bb, figs. 5 and 6, they will form the 
same angle represented by the 
top line of fig. 7. It is there- 

ig.7 fore evident, that if a rectan- 
\ gular plate of speculum metal is 

AAG Sache and oliateell so as to 
form two reflecting facets in- 
clined to each other at the re- 
quired angle, as represented by fig. 7; and this being placed 
at an angle of 45°, with the division of the facets intersecting 
the axis of the object-glass, we shall divide the rays, and 
reflect them horizontally, just in the same way as represented 
in figs. 5 and 6, merely by means of one single reflection. 
Any other direction than a right angle, with respect to the 
axis of the object-glass, may of course be given to the rays, 
by inclining the reflector more or less. From the simplicity 
of this contrivance, and the facility with which it may be 
constructed, I shall take an early opportunity of giving it a 
trial. The only question I have is, whether a material may 
not be found that will reflect more light than even speculum 
metal: I have heard an alloy of cast-steel and platmum well 
spoken of, but have never seen any of it. 

In considering the aberrations which the thickness of glass 
contained in the reflecting prisms must inevitably produce 
when placed immediately behind the object-glass, it occurred 
to me, that if the same prisms were placed close to the top lens 
of the eye-piece, these errors, not being magnified, would be 
less sensibly felt. 

I have before mentioned, that the final image of an object, 
when it leaves the eye-piece, is compounded of several different 
images or perspectives of the object, all blended together, 
and which are as equally capable of separation there as be- 
hind the object-glass itself, as exemplified by figs. 2 and 3, 
which bear exactly the same appearance when under view, 
with the alternate sides of either the object-glass or eye-piece 
stopped off. 

Fig. 8 represents the methods that I have contrived for ob- 
taining the effect of bringing the two eyes sufficiently close to 
each other to enable them both to see through the same eye- 
piece together. aaa are rays converging from the field lens 
of the eye-piece. After passing the eye lens b, if not inter- 
cepted, they would come to a focus at c, but they are arrested 


Wenuam on Binocular Vision. 9 


by the inclined surfaces d d, of two solid glass prisms. From 
the refraction of the under incident surface of the prisms the 
focus of the eye- 
piece becomes 
elongated, and 
falls within the 
substance of the 
glass at e. The 
rays then diverge, 
and, after being 
refiected by the 
second inclined 
surface f, emerge from the upper side of the prism, when 
their course is rendered still more divergent, as shown by the 
figure. The reflecting angle that I hake given to the prisms 
was 471°. I also find it is requisite to erind away the contact 
edges of the prisms as represented, as it prevents the extreme 
margins of the reflecting surfaces from coming into operation, 
which can seldom be daaeies very perfect. 

The definition with these prisms is good, but they are 
liable to objection, on account of the extremely smal] portion 
of the field of view that they take in, and w hich arises from 
the distance that the eyes are of necessity placed beyond tlie 
focus of the eye- piece, where the rays being divergent, the 
pupil of the eye is incapable of taking them all in: : also ici 
is great nicety required in the length of the prisms, which 
must differ for nearly every different alee er. 

I have constructed an adjusting binocular eye-piece, not 
differing in principle from the last. The first reflection is 
performed by means of a triangular steel prism, with the two 
inclined facets very highly polished; this is represented by 
the dotted outline g g, fig. 8. The rays, after having been 
reflected at right angles, are taken up by two rectangular 
glass prisms, shown by the dotted lines at ff. 

The loss of light in this is much greater than in the former 
instance, and the ficld of view more contracted; for the rays 
from the eye-piece, after being reflected from the surface of 
the steel prism, fal] to their natural focal distance, instead of 
being elongated, as in the solid prism, consequently the eye is 
still fiether removed from the focus. I had chosen hard steel 
for the reflector, on account of the property this material pos- 
sesses, of allowing the figure of a small flat surface to be 
retained, or even perfected, during the operation of polishing. 
I have also tried a combination of prisms over the field-glass, 
using two eye lenses, but with no good result. 

The best effect that I have yet produced in the way of 


Fig. 8. 


10 WenuamM on Binocular Vision. 


binocular vision applied to the microscope, is that next to be 
described, in which I have altogether dispenséd with reflecting 
surfaces, merely using three refracting prisms, which, when 
; placed together, are _ per- 
Fig. 9. fectly achromatic. aa, fig. 9, 
is a single prism of dense 
flint glass, with the three 
surfaces well polished. 606 
are two prisms of crown 
glass, of half the length of 
the under flint prism, to the 
upper inclines of which they 
are cemented with Canada balsam. The angle of inclina- 
tion to be given to the prisms must depend upon the dispersive 
power of the flint and crown glass employed. In the combina- 
tion that I have worked out, I have used, for the sake of sim- 
plicity, some flint and crown that Mr. Smith kindly furnished 
me with, in which the dispersive powers are exactly as two to 
one, consequently I have had to make the angle of the crown 
just double that of the flint, in order to obtain perfect achro- 
matism, The refractive power of each must also be known, 
that we may determine the angles of the prisms suitable for 
refracting the rays from the object-glass into the two eyes, at 
a distance of nine inches. cc, fig. 9, represents a ray of light 
incident at right angles upon the under surface of the flint 
prism. On* leaving the second surface and entering the 
crown prism it is slightly bent inwards, and on finally emerg- 
ing it is refracted outwards, in the direction required. 

On looking through this prism I could not discover the 
slightest colour or distortion ; it is almost like looking through 
a piece of plain glass, and the loss of light is so inappreciable, 
that it is difficult to distinguish any ‘difference between an 
object and its refracted image. 

The base of the compound prism should not be larger than 
is sufficient to cover the stop of the lowest object-glass, in 
order that they may be made very thin. 

The method of applying the prism to the binocular micro- 
scope is shown by fig. 10. aa is the object-glass, b the prism, 
placed as close behind it as the fittings will admit. The 
prism is set in an aperture ina flat disc of brass, which has 
an horizontal play in every direction, in order that it may be 
adjusted and fixed in such a position that the junction of the 
prisms may bisect the rays from the object-glass, and at the 
same time be at right angles to the transverse centres of the 
eye-pleces, 

ce are the two bodies of the microscope, provided with 


WenuaM on Binocular Vision. 14 


draw tubes and the usual eye-pieces, dd. The distance between 
them should be rather less than the average distance asunder 
of the eyes, and in cases where 
these are very wide apart we can 
pull out the draw tubes, which will 
increase the distance between the 
eye-pleces. 

With this apparatus I obtain the 
whole of the field of view in each eye, 
which circumstance I was not pre- 
pared to expect, as this must in 
some measure depend upon the cor- 
rection of the oblique pencils of the 
object-glass, for we cannot expect 
to look obliquely through the ob- 
jective of a compound achromatic 
microscope in the same way as in 
the single lens arrangement, fig. 1, 
but can only avail ourselves e aac 
oblique pencils of rays as are cor- 
rected for passing through the axis 
of the microscope. The arrange- 
ment represented by fig. 10 certainly 
gives a larger and better field than 
any other that I have yet tried ; and 
on examining a globule of mercury 
I could not ene er any aberration or inward or outward 
coma when viewed by the eyes, either separately or together. 
I should here mention that the same illusion is occasionally 
produced in the appearance of some objects with the instru- 
ment last described, as mentioned by Mr. Riddell, the vision 
being to some eyes pseudoscopic, or projections appearing as 
depressions, et vice versa. Probably habit would enable us to 
judge of their true form without our being under the necessity 
of resorting to a special expedient for the removal of the de- 
ception. 

I have not yet tried a binucular polariscope applied to this 
instrument, but I have reason to expect some curious effects 
from it. 

I have thus far announced the progress of my expe riments 
towards the attainment of complete binocular vision with the 
microscope, and I cannot too strongly insist on the importance 
of striving to arrive ata perfect result, particularly with the 
highest powers, for I feel convinced that it will be the means 
of ‘settling many disputed points of structure. Whether it will 
require objec tives of a peculiar construction | am not at present 
able to determine, but I may observe that the high power 


Fig. 10. 


12 WenuaM on Binocular Vision. 


object-glasses, as now constructed, are best suited for viewing 
very thin objects. We obtain far more pleasant vision of 
bulk and depth with a smaller aperture. I have no doubt 
that the defects of the larger aperture arise from the confused 
medley of stereoscopic images blended together in one eye, 
and which confusion must increase with increase of aperture ; 
but if, on the other hand, we can divide these images between 
both eyes, then I admit that the aperture cannot be too great, 
as the largest portion of microscopic objects, from the way in 
which they are mounted, would be all the better shown under 
an exaggerated perspective, if I may so express it. 

The binocular microscope has already explained to me 
some of the false appearances arising from oblique illumina- 
tion. I refer particularly to what is known as the diffracting 
spectrum ; for example, if we illuminate the Podura by very 
oblique light, we see a kind of overlying shadow, upon 
which the ae of the scale are also visible. As I can- 
not reconcile this appearance to the known laws of the dif- 
fraction of light, I think that it is miscalled, and appre- 
hend that the ‘phenomenon merely arises from the oblique light 
illuminating one of the perspective images partly as an 
opaque, and the other as a transparent object, and that they are, 
consequently, so far separated as to give the appearance of a 
double image. 

In illuminating objects under the binocular microscope with 
the ordinary*concave mirror some management is required in 
order to get both images equally intense, for we can readily 
get one brilliantly illuminated, while the other is in compara- 
tive darkness, appearing on a black ground almost as an 
opaque object, exactly resembling in their combined effect on 
the eyes what is known as the diffracting spectrum. It also 
occasionally happens that the angle of light from the mirror 
is not sufficient to illuminate both images at the same time. 
These appearances lead me to conjecture that the instrument 
will require a particular kind of illumination, but I am hardly 
yet in a position to express a decided opinion on the subject, 
but will investigate the matter shortly. 

This is the sum and substance of my present experience 
with respect to binocular vision applied to the microscope, 
and I do not think that mere enthusiasm has led me to over- 
rate the importance of the subject, but hope that what has 
already been done is only the commencement of a new era in 
the advancement of this useful and important instrument. I 
believe that there is yet much to be looked for in the way of 


improvement by the investigation of unexplored optical com- 
binations and principles. 


WenuamM on Binocular Vision. 13 


In conclusion I must express my thanks to Messrs. Smith 
and Beck for the prompt assistance that they have afforded 
me in the construction of the instrument, and also for the 
free use of such apparatus, selected from their stock, as might 
be useful to me in conducting my experiments. 


A Short Description of some New Forms of Diatomacex from 
Port Natal. By Geo. Suapspottr. (Read May 25, 1853.) 
Tue constantly increasing interest evinced in the examination 
of the elegant forms of the Diatomacez has recently received 
an additional impetus from Messrs. Smith and Beck’s publi- 
cation of the first volume of the long expected ‘Synopsis of 

the British Species,’ by the Rev. W. Smith, F.L.S. 

A work of the kind alluded to will supply a want that has 
been much felt by microscopists, both as a record of what 
has already been accomplished in this branch of study, and 
also as a foundation for a general system of classification and 
nomenclature, for not only is the latter in the most deplorable 
state of confusion, but by far the greater number of the foreign 
species are only capable of being referred to by their “local 
habitation,” being destitute of the other appendage generally 
considered so necessary. 

Under these circumstances I propose conferring a provi- 
sional name on such new species as Iam about to describe, 
trusting to the indulgence of any prior claimant to this right, 
whom I may unintentionally supplant, and promising to with- 
draw such name on cause being shown. 

About twelve or fifteen months back I was supplied, by the 
kindness of Mr. Geo. Busk, with a gathering of Diatomacee 
from ‘ Port Natal” so rich that I shall not attempt to give a 
detailed account of the forms already known, but, merely 
noticing a few of the most prominent of these, describe more 
particularly those species that are, so far as I am aware, 
entirely new, endeavouring by the respective designations to 
recall them to the mind, by fixing upon some prominent 
peculiarity of appearance in each as the foundation for such 
distinction. 

From the prevalence of certain forms (although I am not at 
all acquainted with the facts of the case) I should be inclined 
to pronounce the locality whence they are derived as subject 
to marine influence, and at the same time probably not far 
from the mouth of some river, and it is also evident that the 
specimens are undoubtedly recent. 

Mixed with the Diatomee are some other bodies, which 
are scarcely capable of being classed with them, although, like 


14 SuapBott on New Forms of Diatomacee. 


the spicula of many of the sponges (of which there is a 
goodly proportion), they are of a siliceous character, such 
as the Dictyocha, and also a form to which my attention was 
directed by Mr. Busk, and which I purpose identifying by the 
name of Bacteriastrum, from Baxrtngia, a stick, and Aorgov, a 
star. 

By the kind assistance of another of our members, Mr. 
Capron, I am enabled to lay before you drawings of these 
most interesting bodies (of which may be distinguished three 
species), as also of most of the other novelties. 

From the tenuity of their structure the various Bacteriastra 
are better observed without being mounted in balsam ; they 
consist of a central irregular annular portion (not unlike the 
connecting membrane which may be observed in the Diatomee 
during self-division), surrounded by from eight to twelve rays, 
each many times longer than the diameter of the central por- 
tion, and the construction of these rays affords a good specific 
distinction, viz. 1st, B. furcatum (fig. 1), the marginal rays 
forked ; 2nd, B. curvatum (fig. 2), marginal rays entire and 
curved in one direction; 3rd, B. nodulosum, marginal rays 
entire, straight, and covered with small protuberances like a 
knotted stick. This last species is by far the most rare.* 

A form tolerably abundant and quite distinct from anything 
I have ever met with from any other locality I propose to call 
Euphyllodium, from «v, and QvAdov, having somewhat the 
outline of a spathulate leaf (fig. 3). It is characterised as 
follows: viz. valve symmetrical, convex, divided by a median 
rectilinear rib, reticulations of an irregular oblong form, dis- 
posed in regular and elegant curves around centres formed by 
the terminations of the median rib. I have noticed but one 
species, which I have called C. spathulatum. There was at 
first some doubt in my mind whether this might not belong 
to the genus Cocconeis, but the very distinct appearance of the 
median line, and the absence of anything that could possibly 
represent the inferior valve, which in the latter genus is 
generally (I believe always) somewhat different from the 
superior one, and likewise the marked character of the outline, 
satisfied me that this supposition was incorrect. It is not 
unlike the aspect of the genus Podosphenia, but here again 
there are differences so distinct as to satisfy me that it cannot 
be referred to it with propriety ; for instance, there is no re- 
flexure of the valve, and the markings are not moniliform 
strie, but rather tessellate in character. 


* Since writing the above, I have made out most unquestionably that 
this pseudo-annular portion is a distinct cell, and not a mere annulus. 


SuapBo tt on New Forms of Diatomacec. 15 


Of the genus Triceratium there are no less than five new 
species, one old, and one doubtful, making seven in all. 

The first I shall notice is of moderate size, and is distin- 
guished by peculiarly delicate markings somewhat obscurely 
disposed about three equidistant pseudo-nuclei— Tr. sculptum 
(fig. 4). 

Next we have one in which the markings appear like 
minute dots, closely crowded together, but disposed in a very 
regular manner from the axis of the valve; this is about the 
same size as the preceding, but the outline differs materially, 
each margin being arcuate with the concave surface outwards 
—Tr. arcuatum (fig. 5). 

Another species of medium size is in form nearly the con- 
verse of the preceding, the margin being so inflated as to cause 
the triangular outline to approach that of the circle; hence 
Tr. orbiculatum as its specific designation (fig. 6). This 
species exhibits a structure similar to that of Coscinodiscus 
radiatus: the reticulations, however, are not so regularly 
hexagonal, but they are largest at the centre, and diminish 
in size gradually towards the margin of the valves. 

I have noticed also a single specimen of what appears to 
be Tr. alternans, but, as it presents only its front view, it is 
difficult to determine. 

The next I shall allude to is, however, the most important, 
being very remarkable and especially interesting from the 
front view exhibiting the disposition of the horn-like append- 
ages (figs. 7a and 7) and the mode of dividing. On the 
lateral view of the valves the most striking peculiarity isa 
sort of twistedness in the angles (fig. 7a), which is very 
marked: the specific name proposed is to note this fact, viz. 
Tr. contortum. 

The surface of each valve is adorned with short spines 
arranged in a tri-radiate double row, and at the termination 
of each double row is one very long one, being about one- 
third of the length of aside of the valve. These long spines 
are independent of and placed nearer to the axis than the 
horn-like processes from which the genus derives its name. 
Fig. 7b shows a specimen undergoing self-division. 

Another new species, much smaller than the last, is charac- 
terized by the reticulations being coarse and irregular in form, 
and the horns very large as compared with the size of the 
valve— Tr. orassum. 

Another species is, I believe, a variety only of the T. favus, 
which has been called gibbosus. 

The genus Pleurosigma has no less than five species, two 
being quite new, and both having the markings arranged dia- 


16 SuapBoit on New Forms of Diatomacee. 


gonally, that is, with (what the Rev. W. Smith considers) 
cells placed alternately in contiguous rows. The outline of 
the largest (fig. 8) is very clumsy and the ends obtuse, and 
the median line but slightly flexed—this | call ‘ validum ;” 
the other, P. inflatum, on the contrary, is of a graceful out- 
line, the apices acute, the flexure of the median line con- 
siderable, and is broad in proportion to its length (fig. 9). A 
third species is, I believe, also new; it was observed by 
Mr. Capron when making the drawings; but as I have not 
had an opportunity of examining it, I have not further no- 
ticed it. Specimens of P. formosum and P. Hippocampus are 
also found, 

There are two new species of Amphitetras, viz. A. ornata 
and A. tessellata ; the former (fig. 10) is of small size, the mar- 
gins of the valves being considerably hollowed or emarginate 
and folded over so that each valve is not unlike in form to a 
collegian’s cap. The surface is elegantly but somewhat irre- 
gularly ornamented with delicate markings. A. ¢essellata (fig. 
11) is of larger size, and the markings coarse and resembling 
a tessellated pavement. 

There is a very striking and beautiful discoid valve, toler- 
ably abundant, of the same genus as one commonly found in 
the guano from Callao, but which, I conceive, has never yet 
had a generic name. It differs in essential characters both 
from the Coscinodiscus and Actinocyclus, and its position 
would probably be midway between them. 

It is possessed of a pseudo nucleus, is minutely embellished 
with delicate markings similar to those seen in Pleurosigma 
anyulatum, &c., but in segments radiating from the centre, so 
that, in all probability, the front view would exhibit slight 
undulations. The absence of any distinct division between 
the segments, however, separates it from Actinocyclus. I 
propose for this form the generic name Actinophenia, from 
axtiv, a ray, and Qzeivos, glittering, with the specific designa- 
tion splendens. 

Fig. 12 is a new species of Eupodiscus, having four pro- 
cesses arranged regularly, and with the markings of a some- 
what similar character to those in the last described species, 
forming an elegant cross; I have, therefore, named it £. 
crucifer. 

Fig. 13 represents a Campylodiscus latus, also new, the cana- 
liculi being wide apart and few in number. 

Moderately abundant in this gathering are specimens of a 
highly interesting nature, on which the generic name of As- 
terolampra has been conferred by Professor Baily, of New 
York: one species, A. marilandica, has been figured in ‘ the 


SHapBott on New Forms of Diatomacee. 17 


American Journal of Science and Art,’ vol. xlviil.; a copy of 
the paper is in the library of this Society, it having been pre- 
sented by the late Mr. Edwin Quekett. The Port Natal 
species differs in many respects from A. marilandica, as the 
following description will show :— 

Frustules disciform, slightly convex, cellular (?), elegantly 
marked around the margin with 7 or 11 segments of an 
elliptical or parabolic outline, radii proceeding from the 
centre to the apex of each segmental curve, and strength- 
ened with bracket-like projections. The aspect is not unlike 
an ornamental wheel, the radii forming the spokes, The seg- 
ments aye regularly and minutely divided into dots or cells (?), 
but it is necessary to use a high power and careful manipula- 
tion to display them: when properly shown, however, nothing 
can well be more exquisitely beautiful. There is a very no- 
ticeable peculiarity in the number of the segments; in every 
specimen I have seen, being either 7 or 11 (a few only of the 
latter number), and in the normal state the two valves, as far 
as my observation extends, are, without exception, disposed 
alternately, that is, that a segment of the superior valve always 
corresponds to an interspace of the inferior one, and vice versa. 
I have named this species A. impar, from the odd number of 
segments. Fig. 14 isa representation of this beautiful frustule. 

A species of another genus, established by Professor 
Baily, Climacosphenia, is shown at figs. 15a and 15), b 
being the lateral view, and a the front view, in which the 
ladder-like divisions more resemble the links of a chain than 
in the only other species I have seen: I have consequently 
ealled it Cl. eatena. 

Two very interesting forms, by no means rare in this very 
rich gathering, belong to a genus that has been described 
under the names of Zygoceros and Denticella, the latter by 
Professor Baily, and as they clearly differ from the former, as 
may be seen by the most casual observer on inspecting fig. 
16, which is a single frustule of a true Zygoceros, moderately 
common in this collection, I shall adopt the latter designation. 
I have only seen them either single or in pairs, having just 
completed the process of self-division, having a somewhat 
persistent connecting membrane. Front views are shown of 
the two new species in figs. 16 and 17. The side view is more 
or less elliptical in outline at the junction of the two valves, 
but sections in almost every other plane parallel to this would 
present a different figure, owing to the protuberances shown 
in the front view. In both species there arise from the cen- 
tral inflations two slightly curved spines from each valve, 
which, as in Triceratium, &c., in the process of self-division, 

VOL, II. c 


18 SHavBo.t on New Forms of Diatomacee. 


are arranged across each other. The smaller of the two spe- 
cies (fig. 16), D. simplex, has but one central inflation, and the 
lateral expansions are symmetrically placed so as to give each 
valve the appearance of a sort of mitre or head-dress. It is 
marked with numerous well-defined dots or cells (?). The 
second species, D. margaritifera (fig. 17), has, besides the 
two lateral expansions, three intermediate inflations, the cen- 
tral one being considerably the largest, and the whole is 
covered by numerous pearl-like eminences similar in aspect to 
those so common in Cosmartum and .other Desmidiee. In 
both species the union of the two valves is marked by a sort 
of projecting band, which completely encircles the frustule. 
In addition to those I have described there are very many 
other forms already familiar to observers of the Diatomea, 
and doubtless some new forms which I have overlooked. I 
am well aware that the present is a most imperfect sketch of 


a highly interesting gathering, containing, as will be shown 


by the following summary, no less than 55 species, of which 

20 are certainly new, and in addition 4 forms of Sponge 

spicula. 

Species. Species. 

Bacteriastrium é . 38 of whichare certainly new 3 
Calophyllum 
‘Triceratium 
Pleurosigma . 
Amphitetras . 
Actinopheenia 
Eupodiscus 
Asterolampra . 
Denticella 
Campylodiscus 
Climacospheenia 
Navicula 
Stauroneis 
Pinnularia 
Nitzschia 
Grammatophora 
Tabellaria 
Striatella 
Zygoceros 
Acnanthes 
Cocconeis 
Doryphora 
Podosphenia . 
Synedra 
Coscinodiscus . 
Tryblionella 
Meloseira 
Biddulphia 
Epithemium . 
Dictyochas 


”? > 


bo 
S| Be DR Re pppoe 


And 4 forms of Sponge Spicules. 


Ou 


on | cere armel ceed cect ee OA cee eel ee SS ell cel ll SO eel SO ell Oo OO SO ell ROMS] Be 


Lree on Sponge Sand. 19 


Observations on the Examination of SponcE Sanp, with Remarks 
on Collecting, Mounting, and Viewing FoRAMINIFERA as 
Microscopic Oxsects, By M.S. Leae, A.I.A. (Read 
June 22, 1853.) 


Various papers on the structure of the Foraminifera have 
been brought before the Society by Mr. Williamson and others, 
but the impression conveyed by those communications has 
been that the shells in question are not very easily obtained, 
and consequently they are likely to be passed over by micro- 
scopists from the want of specimens by which to study 
them. 

Although the matter of this paper has no pretension to 
originality, | am induced to offer these remarks in compliance 
with a suggestion thrown out by a Member of our Council, 
that if Members would occasionally communicate facts, appa- 
rently unimportant in themselves, or new modes of manipu- 
lation under the general title of ‘ Microscopic Memoranda,’ 
such remarks would contribute to diffuse a taste for the pursuit 
by facilitating the labours of those whose time and inclination 
admit of such researches. 

Under this impression I now lay before the Society the 
result of my experiments on sponge sand, and the methods 
employed to bring the specimens more immediately within 
my reach without ‘the labour of picking them out from an in- 
discriminate sample of the sand itself. 

Having observed that there was some degree of uniformity 
in the magnitude of certain species of the Foraminifera, it 
occurred to me that by sifting the mass of sand through wires 
of different gauges important results would follow, and I 
therefore obtained some specimens of wire-gauze of 10, 20, 
40, 70, and 100 wires to the inch, and, having also procured 
from a sponge merchant about a peck of the rubbish arising 
in sorting the sponges, I proceeded to separate the sand into 
parcels of different degrees of fineness, 

In the first process (employing a gauze with 10 wires to the 
inch) I cleared the mass of clippings of sponge, small pebbles, 
&c., without obtaining any specimens of shells worth retaining. 

In the second (20 wires to the inch) I obtained some very 
nice specimens of the Orbiculina adunca and complanata, but 
scarcely anything else; these specimens, of which the Mem- 
bers may recollect that Dr. Carpenter exhibited a series of 
very beautiful drawings at one of our soirées, were thus brought 
together, instead of being, as before, scattered through the 
mass, at intervals few and far between. 

c2 


20 Leae on Sponge Sand. 


By means of the third gauge of wire-gauze, specimens of 
Peneroplis, and smaller specimens of Orbiculina, were brought 
together, with other species of Yoraminifera of considerable 
variety of beauty and form, the result here obtained being 
very decided and characteristic of particular species; for, 
although the quantity retained after this process was compara- 
tively small in relation to the original mass, yet the specimens 
were such as to afford an ample reward for the time and 
trouble incurred in obtaining them. 

But the most surprising result was obtained by using the 
next quality of wire-gauze (that of 70 wires to the inch), the 
amount retained being much larger in quantity, and the pro- 
portion of shells to sand and other débris being such that 
sliders mounted indiscriminately from it yielded several very 
good objects in every instance. 

From the above samples I was enabled to select, without 
difficulty, shells for microscopic observation; in the first two 
by the naked eye, and in the latter by using a hand magnifier, 
and removing them with the moistened point of a camel’s-hair 
pencil. 

‘The remaining portion of sand, forming probably 19-20ths 
of the original mass, will contain, as may easily be imagined, 
a very small comparative quantity of shells; but, nevertheless, 
it must not be thrown away. I again passed some of it 
through a gauze of 100 wires to the inch: the sample then 
retained yielded a fair quantity of shells by washing it in 
water, and thus other species characterized by their size were 
brought out by adopting the following process: having selected 
a dish of sufficient size and depth, and spread at the bottom 
of it a quantity of the sand, as much water was poured on it 
as would cover the whole to the depth of half an inch; after 
allowing the floating particles to settle, the dish was slightly 
raised at one end and gently agitated, so as to produce little 
eddies in the water. Inashort time it was observed that small 
channels were formed in the sand of a whiter aspect than the 
other portions ; allowing the water to settle gradually, the dish 
was slowly tilted at one end until the surface of the sand was 
exposed : the whiter particles being then carefully removed by 
means of a camel’s-hair pencil, they were found to consist 
almost entirely of very minute shells; and the process being 
repeated a few times a large amount (microscopically speak- 
ing) was obtained for future examination. 

In connexion with this subject I may venture a few remarks 
upon collecting, mounting, and viewing specimens of the Fo- 
raminifera as far as my experience has enabled me to speak. 

When about four years ago I was staying at Weymouth 


ie on 


Lrae on Sponge Sand. 21 


with my friend Mr. Woodward, in walking over the Small- 
mouth Sand, which is situate on the north side of Portland 
Bay, we observed the surface of the sand to be distinctly 
marked with white ridges, extending many yards in length, 
and parallel with the edge of the water. Upon examining 
portions of these we found that they consisted of Foraminifera 
in considerable abundance, and, upon scraping up a quantity 
of it carefully with a card, we obtained in a short time a 
bottleful of material which contained thousands and probably 
millions of these minute shells. 

My friend Mr. Cocken, during a recent residence at 
Brighton, was very successful in obtaining a considerable 
quantity of the Foraminifera from the surface of the mud 
exposed by the receding tide in Shoreham Harbour ; and here 
also the surface only should be taken, in order to have a large 
proportion of shells. 

It is very well known to many of our Members that the 
ouze from the oyster beds yields a very fair proportion of 
Foraminifera and other materials for microscopic examination, 
and I am inclined to think from these evidences that the sur- 
face, and the surface alone, of sand or mud banks will yield 
satisfactory results. And I should recommend to all those 
who contemplate collecting for themselves, or employing others 
to do so for them, to take only the surface, being convinced 
that a few spoonfuls obtained in this way will yield more 
than a spadeful taken indiscriminately. My view of this is 
also confirmed by the large amount of shells in the sponge 
sand, for being taken from the sea-shores, that which is 
gathered up with them is such as occurs only on the surface. 
I think it also very probable that a locality shelteredyfrom the 
direct action of the sea would be more favourable for finding 
these organisms than a bold shore exposed to all the violence 
of the wind and waves, 

If these conjectures should be borne out by experience, it 
is to be hoped that the increased facilities of finding their 
habitats will lead to extended observations on their living 
economy, a subject rendered extremely interesting by the 
papers of Mr, Williamson and the writings of Dr. Carpenter 
and others, where the subjects of their structure and zoological 
position are very ably discussed. 

The species of Foraminifera are so numerous that the mere 
mention of 575 species described by D’Orbigny as peculiar 
to the torrid zone, 350 species to the temperate zone, and 75 
species to the frigid zone, sufficiently attests their abundance, 
and the samples of sand which have come under my own 
observation from the Caramatta Strait in the China Sea, from 


22 Luce on Sponge Sand. 


Australia, and other localities, afford ample proof of numerous 
and beautiful forms. 

After collecting these minute shells, two very important 
points are, mounting them for future examination, and viewing 
them so as to obtain their true structure. Much depends on 
the different genera, as to the most eligible mode; the simplest 
and most natural is that adopted by Mr. Marshall of placing 
them in cells made of perforated card, putting a piece of thin 
glass over and sealing it down, so that the objects roll about 
loosely, and are viewed as opaque objects by a side light; 
another mode, also adopted by the same gentleman, is placing 
the shells on a glass slip with a little very dilute gum water, 
which causes the shells to adhere sufficiently to the glass as 
to admit of the air being exhausted from them when mounted 
in Canada balsam. They may then be viewed either as opaque 
or transparent objects, but it will be observed that the texture 
of the shell which invests the segments of the animal is (as 
observed by M. d’Orbigny) very variable, but it almost always 
follows the different mode of growth upon which the orders of 
that author are founded. When the segments are closely packed 
together, the shell is opaque, of a close texture like porcelain, 
and without any indications of external porosity; when the 
segments are alternate without a spire, and when the spire is 
oblique, the shell is porous, and pierced over the last cells 
with a great number of little mouths, through which proceed 
the filaments, but which become obliterated when the animal 
no longer needs them; when the segments are im a straight 
line, when they are coiled upon the same spiral plane, or 
when they are alternate, and the shell inequilateral, their 
texture ig almost as transparent as glass. 

From the above description it will be evident that one 
single mode of illumination will not suffice for duly developing 
the structure of these shells, and I should therefore recommend 
that some be mounted loosely in a cell, so that all parts may 
be viewed as they roll over; and others be mounted in Canada 
balsam, and viewed by means either of the annular condenser 
of Mr. Shadbolt or the parabolic reflector of Mr. Wenham. 
By these means the difference in structure between the upper 
and under surfaces of the same species of shell is brought out, 
and that confusion avoided which occurs when direct light is 
transmitted. 


Rainey on Artificial Light. 23 


A Method of employing Armriciat Lieut for the Ittumina- 
TION of TRANSPARENT OBsects, by which it is so deprived of 
Glare and Colour as to be equal in its Illuminating Power to 
the best Daylight. By Gero. Rainey, M.R.C.S., Demon- 
strator of Anatomy atSt.Thomas’s Hospital. (Read June 
22, 1853.) 


Tue principal disadvantages attending the use of gas and 
lamp light, as they are ordinarily employed for microscopic 
illumination, are the disagreeable and somewhat painful glare 
and the unnatural colour which is given to all objects thus 
illuminated. 

These inconveniences are not felt so much where only a 
plane or concave mirror is used, as when the light is concen- 
trated upon the object by an achromatic condenser ; and, in 
the former case, they are partially remedied by transmitting 
the light through a piece of ground glass, either common or 
coloured ; or by dulling the surface of the mirror; but in the 
latter one, these means, by cutting off too much light, are 
productive of more harm than benefit, especially where the 
markings upon an object are very delicate and require a parti- 
cular kind of illumination to render them distinctly visible, 
as, for instance, the dots on the Pleurosigma angulatum. 
Hence, unless some other plan be adopted for moderating the 
intensity of all artificial light and correcting its colour, the 
employment of the achromatic condenser must either be 
limited to the hours of a good daylight, or the observer be in 
danger of materially injuring his eyesight. 

Mr. Gillett’s apparatus for producing the effect of a white 
cloud does, I am informed, remedy all the defects of lamp- 
light, but, from some difficulty or other in constructing or in 
applying it, its employment has not become general. 

The plan to which I have to call your attention is especially 
applicable to Mr. Gillett’s condenser, and may at a compa- 
ratively small expense be made a part of that most useful 
instrument. 

Before proceeding further I may observe that the principle 
upon which my apparatus is constructed is one which has 
been of general adoption for the preservation of the eyes of 
those who use glasses, and therefore so far has no claim to 
originality ; but its precise construction and application to the 
microscope, and its effect in rendering artificial light equal if 
not superior to the very best daylight, are admitted by those 
who have seen it, and, to the best of my knowledge, are also 
new. But my motive has not been novelty but utility, in 
bringing this subject under the notice of this Society. 


24 Rainey on Artificial Light. 


Now that which gives the peculiar burnish or glow to all 
objects when highly illuminated, whether by the direct rays of 
the sun, or by light proceeding from ignited matter, is due to 
the heating portion of the spectrum and certain coloured rays. 
In the former case we make use of light for microscopic illu- 
mination which has been deprived of this burnish by its 
having passed through the clouds; and in the latter this can 
be equally well effected by passing the light emanating from 
gas or a lamp through such transparent coloured media as 
will stop the calorific rays, and at the same time furnish the 
kind and amount of colour necessary to form, with the coloured 
rays of the flame, white light. 

The combination which I find to answer best is the fol- 
lowing :-— 

One piece of dark blue glass, free from any tint of red, one 
of a very pale blue with a slight shade of green, and two of 
thick white plate glass, all cemented together with Canada 
balsam. 

This combination so completely stops the calorific rays, that 
when the direct rays of the sun are concentrated by a bull’s 
eye of the ordinary size upona lucifer-match with this medium 
intervening, it does not become ignited ; and when this medium 
is used with Gillett’s condenser, objects illuminated by the 
light of a camphine lamp appear as if they were seen by a 
bright daylight. 


Boswe tt on Actinophrys Sol. 25 


Remarks on Actinopurys Sot. By R.S. Boswetx, Spring 
Hill Cottage, Charmouth, Dorset. (Read Oct. 26, 1853.) 


In an interesting paper in the ‘ Journal,’ of a description 
of Actinophrys Sol, by A. Kolliker, &c., (Vol. I., pp. 25 
and 98,) the author, after entering into a very minute descrip- 
tion of this curious animalcule, says:—‘‘ The creature also 
seems to be capable of altering its entire form to a certain 
extent, and to be able to expand and again contract itself i 
toto. More extensive and more energetic movements do not 
occur at all, and I am consequently altogether ignorant as to 
how locomotion of the animal is effected.” My object in 
sending this short notice is to give him that information which 
he seems to want, though perhaps by this time he may have 
made the same discovery as myself, if not, it cannot but be 
interesting, not only to him, but also to others, who take an 
interest in these minute wonders of creation. 

The “Sun animalcule” is very common in this part of 
Dorsetshire ; it abounds in pools where Desmidiee are found : 
they are ravenous feeders, not only upon the Desmidiee, but 
also upon all kinds of minute spores and animalcules. It was 
on examining some beautiful Desmidiee, a few evenings 
back, that my attention was arrested by the curious appearance 
of two or three very small Actinophrys floating very lightly 
upon the surface of the water in the form of a ball, with their 
delicate tentacular filaments perfectly erect all over their 
bodies ; in fact, they seemed to be floating upon these delicate 
filaments. This beautiful and curious appearance, so different 
from what I had generally observed, induced me to request 
Mrs. Boswell to look at it, but, while she was rising from her 
seat, I exclaimed, ‘‘ You are too late, the little creature has 
given a leap, and I have lost it!’ but upon moving the slide 
in the direction of the leap, I found the creature composedly 
resting in the usual manner upon the surface of the water— 
that is, in a flat position. This was not a solitary instance, for 
about five minutes after another gave a similar leap: the dis- 
tance must have been very great considering the size of the 
animal, as it was in the centre of the disc under Messrs. 
Smith and Beck’s 2-3rd object-glass with the second eye-piece, 
and I had to travel full an inch beyond the radius. These are 
the only two instances I have met with at present, not having 
made the little creature my peculiar study. 

I have frequently mounted the Actinophrys Sol with Des- 
midiee, but they generally burst at the edge of the sphere 
owing to the pressure of the glass cover, although they are to 

VOL, II. 


26 _ Busx on Avicularia. 


all appearance considerably thinner than Micrastorias denti- 
culata. 


Remarks on the Structure and Function of the AvicULaRiaNn 
and ViBracuLaR Oreans of the Potyzoa; and on their 
value as diagnostic characters in the classification of those 
creatures. (Read Nov. 23, 1853.) 

2, one class of the 


Tue Polyzoa, or, more properly speaking, 

Polyzoa characterized by the possession of a movable semi-cres- 
centic lip, furnished with a corneous rim, at the mouth of the 
cell,—the cheilostomata as I have elsewhere termed them, or 
Celleporina of Ebrenberg,—are, many of them, distinguished 
by the presence of appendicular organs affixed to one part or 
another of the cells of which the polyzoarium is composed. 
These organs are of*two kinds, the one a sort of pincers, and 
the other consisting of a long, slender, movable seta. To the 
former set of organs, of whatever form, the term aviculariwm is 
here applied, and the latter are designated as vibracula. 
With respect to the structure of these organs of either class it 
is sufficient to remark that, however diverse their appearance 
may be, they are all constructed upon the same general type, 
that is to say, the organ consists of a hollow cup or receptacle 
containing two sets of muscles for the movements of its motile 
portion, the mandible, as I term it in the one case, and the 
seta in the other. Beyond this general conformity in type, 
however, my knowledge of the more intimate structure and 
contents of the cup in the vibracular organs, does not allow me 
to approximate them to the avicularia. 

The avicularia, besides the movable mandible, it may be 
observed, always have a corresponding fixed beak, the opponent 
as it were of the mandible, and necessary to constitute the 
organ, what I presume it to be, an instrument of prehension. 
This beak is needless, and is therefore wanting in the vzbra- 
cula, and its absence in cases where the movable part is 
detached, would serve to distinguish one kind of organ from 
the other. 

I, The avicularia.— 

The first notice we have of the existence of these organs 
or rather of one form of them, is contained in Ellis’s account 
of what he terms the ‘ Bird’s-head coralline,” (Nat. Hist., 
Zooph., p. 36, pl. 20,) where he says, ‘‘ On the outside of each 
cell we phe by the microscope, the appearance of a bird’s 
head, with a crooked beak opening very wide.” 


Busk on Avicularia. 27 


Mr. Darwin, in the ‘ Voyage of the ‘Adventure’ and 
‘ Beagle,’ adverts at some length to these organs, and de- 
scribes their actions in the living state very graphically. They 
have also been described with great care by Dr. Van Beneden 
and the late Professor John Reid, and also by Nordmann 
and Krohn, the latter (as I extract from Dr. Johnston’s ‘ Hist. 
Brit. Zooph.’) classifying them under three different forms: 
1, those which have the figure of the crab’s arms; 2, those 
which resemble pincers; and 3, those which are formed like 
bristles or hairs; the last corresponding to what are here 
termed the vibracula. 

In a paper read before this Society, October 27, 1847, and 
published in the ‘ Transactions,’ I have described more particu- 
larly the structure of the curious and unique form presented 
by this organ in Notamia bursaria, pointing out, I believe for 
the first time, that the muscles were divisible into two distinct 
sets, one for the closure and the other for the opening of 
the mandible, with other minute particulars of their mecha- 
nical arrangement previously unnoticed ; I also stated that the 
muscles not only in this organ but throughout, in this and 
other Polyzoa, are of the striped kind, or resembled those of 
the Brachiopoda more than of any other class in the Mollusca. 
I also indicated that the mandible and the beak of the cup 
were differently constituted to the rest of the organ, being com- 
posed of a horny instead of calcareous substance ; and that 
besides the two sets of muscles above noticed, the cup con- 
tained a “ peculiar body of unknown nature.” 

I believe that up to the present time our knowledge of these 
organs is pretty nearly limited to the above particulars. With 
respect to their homologies and functions, nothing but con- 
jectures have been offered; in fact, as regards the homo- 
logies of these organs with any existing in animals belonging 
to the same or any other class, no conjectures beyond the most 
vague have been offered. They may, perhaps, be regarded as 
analogous in function with the Pedicellarie of the Echino- 
derms, as well as with the little accessory cups filled with 
prehensile filaments, or thread cells, which are found in the 
Plumularie and Campanulariade; but, I conceive that any 
homology with these organs is quite out of the question. 
They are as nearly related to the claws of a lobster or the feet 
of a Pygnogonum.* 


* Mr. Huxley has pointed out to me several points of resemblance be- 
tween the avicularia, especially as to their mechanical and muscular ar- 
rangements, and the shells of the Brachiopoda. An ingenious idea, and 
calculated to lead to the more serious consideration of the relationship 
between the Polyzoa and Brachiopoda, as suggested by Mr. Hancock 


d 2 


28 — Busk on Avicularia. 


Their structure so obviously indicates their aptitude for pre- 
hension, that the supposition of such being their function has 
been long entertained: and I have myself no doubt whatever 
as to its being so; for, as Dr. Johnston observes, “ although 
they are too short to hand the prey to the mouth, yet, retained 
in a certain position, and enfeebled or killed by the grasp, the 
currents set in motion by the ciliated tentacula may then 
carry it within reach.” (‘ Brit. Zooph.’ p. 334.) Some time 
in the last year, a specimen of Scrupocellaria scruposa, if 
I remember right, was exhibited at one of our meetings, with 
a minute vermicule, retained in the grasp of its avicularia ; and 
the same thing seems to have been repeatedly noticed. An 
instance of the kind occurred to me when at the sea-side this 
autumn, and I have made a figure to represent the occurrence 
(Plate IT. fig. 12). It is ofa portion of Scrupocellaria seruposa, 
two of the -avicularia on which have, apparently simulta- 
neously, caught a minute vermicule which they retained with 
a most tenacious grasp. I kept the zoophyte under observa- 
tion for several days, in the living state, and during that time, 
in fact, till the whole died, the grasp of these organs was not 
relaxed ; and, although the movements of the captive were 
very active and apparently energetic, it was unable to liberate 
itself from the grim hold of its tiny but persevering antagonist. 
Another instance of the grasping propensity of these organs 
is exhibited in fig. 10, where two of them appear to be 
engaged in deadly combat. This figure is also intended 
to show the disposition of the muscles when thus employed. 

Considering, therefore, the conformation of the avicularia, 
and the instances in which objects of prey of different kinds 
have been noticed engaged by them, I think it is impossible 
to avoid the conclusion that they are for the prelension of ob- 
jects, either for the purpose of using them for food when dead 
and powerless, as suggested by Dr. Johnston; or it may be for 
purposes of defence. 

With respect to the structure of the avicularium, I have 
already stated what is known; and have, in addition, only 
to remark that it has occurred to me to notice a circumstance 
hitherto overlooked, and which may eventually serve to throw 
some light upon the “ peculiar body” contained in the cell to 
which I adverted in my observations on Notamia. It was in 


(‘ Ann. Nat. Hist.,’ 2nd Ser., vol. v. p. 198), than has hitherto been given 
to it. And with regard to this, it should be borne in mind, though per- 
haps the character is of no great importance, that all the Brachiopoda 
have striped muscular fibres, whilst for the most part the other classes of 
Mollusca, with some exceptions—Pevten, for instance—all have muscles of 
the unstriped kind, 


Busk on Avicularia. 29 


that species, also, that I first noticed (in 1852) the fact that 
when the mandible is thrown back, or, in other words, when 
the avicularium is open, a slight prominence comes into view, 
covered with delicate setose hairs, which do not seem to be of 
the nature of cilia, because they exhibit no motion. These 
minute sete appear to he seated on the “ peculiar body ” above 
adverted to, and which again seems to be so connected with 
the muscles by which the mandible is closed, or rather, 
perhaps, to a membrane by which they are covered, or by 
which the opening of the cell is closed, when the mandible is 
thrown back, as to be protruded, simply by the throwing back 
of that process; so that the sete are then made to project 
beyond the level of the cup, and are withdrawn as the man- 
dible closes. Fig. 2 represents this apparatus in Notamia. 
Fig. 7, the same thing in Bugula plumosa, and fig. 9, in 
Bugula avicularia. These are the only three species in 
which, up to the present time, I have been able to perceive 
this arrangement ; but not having had an opportunity of ex- 
amining the avicularia of any other, except Serupocellaria 
seruposd, for the purpose, and in wien I was unable to detect 
it (fig. 15), I am not prepared to say that it obtains univer- 
sally. It is probable, however, that in a modified form it may 
do so. Iam inclined to the opinion that it is atactile organ, 
the object of which is to apprize the occlusor muscles of the 
contact of any minute floating object, upon which the muscles 
immediately contract, and either close the avicularium against 
the invasion of a foe or capture the appropriate prey. 

A second point that I have also observed in these organs, 
and which, I believe, has not been before noticed, is that the 
portion of the cup in which the muscles and the greater part 
of the peculiar organ (which might probably be regarded as a 
nervous ganglion) are placed, is closed in by a delicate mem- 
branous tympanum, which has a central perforation, through 
which the conjoined tendon of the occlusor muscles passes, and 
also a second smaller opening (at all events in B. avicularia), 
the object of which I do not know. This tympanic mem- 
brane is shown in fig. 8. 

So much for the structure and conjectural function of the 
avicularia ; and to proceed to consider the vibracula in the 
same particulars. 

1. As to the structure of these organs, I have nothing new 
to offer. They consist, as I have said, of a cup containing the 
muscular apparatus, and of a movable seta, articulated to the 
cup, and which appears to be moved in the same way as the 

mandible of the avicularia. This seta is in most cases simple 
and terete ; in others, as, for instance, generally in the genus 


30 Busk on Avicularia. 


Caberea, it is toothed on one side; and in others, as in the 
species forming the family Selenariade, of which we have no 
British representative, the seta is very variously and curiously 
formed, in some being trifid or bifid at the extremity, and in 
one, Selenaria maculata, it is spirally contorted and minutely 
annulated, so as very closely to resemble the proboscis of a 
butterfly. 

As to the function of the vibracula, it would appear, in most 
cases, to be simply defensive. The seta may be observed in 
almost constant motion, sweeping slowly and carefully over 
the surface of the polyzoary, and removing what might be 
noxious to the delicate inhabitants of the cells when their 
tentacula are protruded. 

Another circumstance often to be observed with respect to 
these organs, is this, that each presents inferiorly a rounded 
perforation, as in Scrupocellaria and Canda, sometimes chan- 
nelled as in Caberea, which indicates the point of attachment 
of a radical tube or fibre. That this connexion with a radical 
tube, however, is not an essential attribute of the vibracular 
organ is sufficiently obvious from the circumstance that those 
tubes are frequent where no such organs exist; but where 
there are vibracula, the tubes invariably enter them, and not 
the cell itself. This is especially evident in the genus Canda, 
of which the British species, Canda ( Cellularia) reptans, affords 
an instance. 

In the case of the Selenariade or Lunulites, 1 think it not 
improbable that the vibracula may be subservient to loco- 
motion. 

These organs, both avicularian and vibracular, appear to me 
to be of very considerable importance in a systematic point of 
view ; and, although from our imperfect knowledge of them, 
and in fact of the Polyzoa in general, the supposition can only 
be regarded as problematical, it seems not improbable that 
the presence or absence, especially of the avicularium, may be 
connected more directly with the intrinsic nature of the 
species upon which they are found, than has hitherto been 
supposed. It may, for instance, be the case, that those furnished 
with these offensive weapons live upona kind of food different 
from that of the others who do not require such an aid in the 
capture or weakening of their prey. The Polyzoamay, per- 
haps, thus be divided into vegetable and animal feeders, or into 
feeders upon dead, and those which feed upon living organisms. 
One thing, however, is certain, that these organs afford, in many 
cases, excellent and available systematic characters ; and this 
part of the subject I will now proceed briefly to discuss. 

I have already stated that the accessory organs we are now 


Busk on Avicularia. 31 


considering are divided into two kinds, apparently with dis- 
tinct functions—avicularia and vibracula; the one, probably 
prehensile, the other defensive. Of these, the avicularia are 
found by far the most extensively ; in fact, they are wanting 
in but few of the genera constituting the chetlostomatous 
class of Polyzoa. In employing them for the purpose of 
classification, it is necessary to subdivide them into three 
classes. 1, the pedunculate. 2, the sessile; and 3, the 
immersed. The two latter cladaest however, run insensibly 
into each other, whilst the pedunculate form is obviously 
quite distinct, inasmuch as it presents an additional member, 
in the form of a basal joint. It is this form of avicularium to 
which the term “ birds,” or “ vultures’ heads,” is more pro- 
petly applied. It is well known in this form, as it occurs in 
Bugula avicularia, B. plumosa, and B. flabellata: it is also 
found in Bugula tridentata (Krauss), a South African species ; 
and in Bicellaria ciliata; whilst it is wanting altogether in 
Bugula neritina, Bicellaria grandis, and Bicellaria gracilis. 
A second modification of pedunculate avicularium, where it 
assumes the form of a long trumpet-shaped or infundi- 
buliform tube, exists in Bistilania tuba. So far as I know 
then, at present, the pedunculate form of avicularium is 
restricted to the genera Bugula and Bicellaria, though it does 
not exist in every species of either genus, and in one, assumes 
a form quite different from the ordinary. All that can be 
said about it, therefore, in those two genera, is that where the 
avicularia exist, they are of the pedunculate variety. The 
true ‘ bird’s-head” avicularia are always placed on the an- 
terior aspect of the cell, on one side below the level of the aper- 
ture, whilst the tubiform variety arises on the back of the cell. 
The sessile form of avicularium, as I have observed, may 
be subdivided into the projecting and the immersed. = 
these, the latter is much the more extensively distributed : 
is placed either at the angles or margin of the cells, or on 
some other part, usually of their anterior aspect, but some- 
times on the posterior: instances of the latter are presented 
in Caberea nuda, where the vibracular organs, so characteristic 
of the other species in the same genus, are replaced by what 
may be termed avicularia, though, in fact, they should more 
properly be referred to the vibracular type, inasmuch as 
the radical tubes enter their bases. The genus Retepora, also 
offers an instance of the posterior position of true avicularia ; 
but, with these exceptions, I am not acquainted with any 
other in which the avicudaria are not on the sides or front of 
the body, as indeed, if our surmises with respect to their func- 
tion be well founded, might be expected. 


32 Busk on Avicularia. 


Of angular imbedded avicularia, the numerous species 
of the genus Catenicella afford examples. This organ, in 
fact, in that genus, often furnishing very satisfactory specific 
characters. In some, as C. plagiostoma, it is of gigantic size, 
in others very minute, and in one it seems to be aborted, being 
replaced by channelled processes, C. carinata. In several 
other species it is in some cells replaced by long ascending 
cornua or hollow spines, as in C. cornuta and C. taurina. 

The genera Menipea, Canda, Scrupocellaria, and Cellularia, 
are respectively distinguished by the presence or absence of 
avicularian and vibracular processes. ‘The former are always 
of the sessile kind, either immersed, and at the superior and 
outer angle of the cell, or projecting and placed on the front 
of the cell, below the level of the aperture. In the genus 
Menipea, there is an angular, superior, imbedded avicularium 
in many of the cells, and a projecting sessile organ on 
the front of the cell below the aperture, and no vibracula. 

The British species, Menipea ternata, affords an instance ; 
the other species similarly characterized, are—M. cirrata, 
M. fuegensis, M. triseriata, M. ornata, M. patagonica, and 
M. multiseriata. The genus Canda, differs from Scrupocel- 
laria, mainly in the want of any avicularian process at 
the superior and outer angle; but the cells sometimes have a 
sessile avicularium in front, below the aperture. This is 
particularly the case with Canda arachnoidea, in which the 
avicularia appear to occupy an unusual position: they do not 
seem to be seated on the fronts of the cells themselves, but to 
form a series affixed to the median septum between the two 
rows of cells ; and, what is very curious with regard to them 
in this species, they are apparently developed long after the 
completion of the cells, seeing that they are totally wanting 
in the upper and younger portions of the branches of 
the polyzoary, and gradually increase in size towards the 
inferior portion. In Scrupocellaria, we arrive at the full 
development of these accessory organs; the species in this 
genus being all distinguished by their being furnished with 
both avicularia and vibracula. Of the former, one is always 
imbedded in the superior and outer angle, as in Scrupocellaria 
serupea, S. scruposa, and S. Macandrei ; whilst in others, such 
as §. ferox, and S. cervicornis, there are superadded to these, 
sessile avicularia on the front of the cell below the aperture, 
in the former species, of colossal dimensions. The genus 
Cellularia, again, is distinguished by the entire absence 
of both avicularia and vibracula. The British form Cellularia 
Peachit, affords an instance. 

The genus Caberea, except in the single species above re- 


Busk on Avieularia. 33 


ferred to, and which might, perhaps, on that account, almost be 
regarded as the type of a separate genus, is distinguished, and 
very remarkably so, by the extraordinary size and curious 
arrangement of the vibracula on the back of the branches, 
which thence derive a very close resemblance to an ear of barley. 
It is in this genus that the vibracular organ acquires its ex- 
treme development. A British example is afforded in Caberea 
Boryi, a not uncommon denizen of the Channel coasts. In 
the genus Emma, we have afforded an instance, in which the 
position of the organ may be used in the generic character. 
In the species belonging to this genus, the sessile, lateral 
avicularium is situated on a level below the aperture. £. ¢., 
Emma erystallina and E. tricellata. 

The peculiar disposition and form of the avicularia, in 
NNotamia, have been sufficiently adverted to in this and my 
previous communication to the Society. 

It would require too much of your time and too much 
space to enter very particularly into all the instances in which 
I have found the form, position, and existence of ayicularia 
and yibracular processes useful in the classification of species. 
The above remarks, hasty as they are, will serve to give 
an idea of the extent to which they may be so employed ; 
and I would only observe, in addition, that a similar atten- 
tion to these organs will be found indispensably requisite for 
the due appreciation of specific and even generic distinctions, 
in the difficult and hitherto much confused families of the 
Flustrade, Membraniporide, and especially of the Celleporide, 
Escharade, and Selenariade. In Lepralia, particularly, in 
which genus I have placed nearly 60 species, I have found the 
use of these organs of the utmost importance, and easily avail- 
able. In fact without them it would have been a most difficult 
task to marshal into due order such an irregular and mutinous 
host. For the mode in which I have so employed this 
character, I must refer you to my ‘ Catalogue of Marine 
Polyzoa, just published by the British Museum, and will 
conclude by saying, that the names of the Polyzoa here em- 
ployed are those by which they are distinguished in that 
work, in which the appropriate synonyms will be found. 


34 Structure of a peculiar Combustible Mineral, 


On the Minute Structure of a peculiar CompustiBLe Mine- 
RAL, from the Coal Measures of TorBANE-HILL, near Batu- 
GATE, LintirHGowsHiRE, known in Commerce as BoGHEAD 
Cannet Coat. By Joun Quexerr, Professor of Histology 
to the Royal College of Surgeons of England. (Read 
Noy. 23 and Dec. 21, 1853.) 


Tue substance in question has lately excited the greatest 
interest in the scientific world; and a trial, second to few in 
importance, has recently taken place in Edinburgh, haying 
for its object the determination whether the Torbane-hill 
mineral should be called a coal or not, and whether it should 
be included in the missive of agreement for a lease, and let as 
coal. Those of my hearers who may wish for a particular 
account of the matter in dispute, and a statement of the facts 
brought forward, both by the pursuer and defender, or, with us 
in England, plaintiff and defendant, | would beg to refer to 
Mr. A. W. Lyell’s Report of the trial, published by Messrs. 
Bell and Bradfute of Edinburgh. 

Upon this trial no less than seventy-eight witnesses were 
examined—thirty-three for the plaintiff, and forty-five for the 
defendant. They might be classified as geologists, mineralo- 
gists, chemists, microscopists, and practical engineers, such as 
gas managers, miners, &c. 

With four‘of these classes of scientific witnesses I have no 
immediate concern, and will, therefore, leave them to settle 
their own differences ; but not so with the microscopists, with 
many of whom my opinions are entirely at variance. 

In order that you may all fairly understand the nature of this 
question, as far as the microscopical observers are concerned, 
I will, in the first place, give you a detailed account of the 
minute structure of the Mineral itself. Secondly, I will givea 
brief description of the minute structure of Coal. Thirdly, I 
will lay before you the whole of the evidence given by the 
microscopists on the part of the pursuer as well as the defender; 
and lastly, make a few remarks upon the conflicting testimony 
of some of the witnesses. 

I wish that the matter had fallen into abler hands than 
mine; but having been intimately acquainted with the 
mineral in dispute for some time past, and as two of the oldest 
members of this society, Mr. Bowerbank and myself, have 
had their competency called in question, and have been repre- 
sented by the Judge as no botanists, and, therefore, “are not, 
as I understand, conversant or skilful in fossil plants,” and the 
society itself not having escaped his ridicule, the jury being 


from the Coal Measures of Torbane-hill. 39 


informed that the Microscopical Society of London is “a 
learned body, who make it their object to pry into all things,” 
I cannot be silent; but I would have you keep in mind that 
my sole motive in now appearing before you, is, the cause 
of truth, and in this cause I come forward fearlessly, but 
honestly, to state that the Torbane-hill mineral is not, micro- 
scopically speaking, a Coal ; that it is not like any of the combus- 
tible substances used in this country as Coal ; and that, althouyh 
possessing some of the properties of Coal, it is, notwithstanding, 
a mineral sui generis, having a basis of clay which is strongly 
impregnated with a peculiar combustible principle, and that when 
plants are found in it, they are accidental, and have no more been 
concerned in the formation of the mineral than has a fossil bone 
in that of the rock in which it may be imbedded. 

1. External characters of the Mineral.—Of these you will 
have a good general idea from the specimens on the table before 
you. It frequently occurs in seams of some considerable 
thickness, and always in the neighbourhood of coal, some- 
times in immediate contiguity with it, but at other times, 
according to Mr. Ansted, separated from it by a layer of fire- 
clay. The colour is generally a dark brown or black, without 
lustre, but varies according to its position in the seam; 
its specific gravity is 1,2, or 1,%;, water being as 1. When 
scratched with a knife it exhibits a brown streak, in which 
particular it is said to differ from all the known coals with one 
or two exceptions. It is tough and not so brittle, but that 
very thin sections may be made of it, and when struck with a 
hammer, it emits a dull sound; the remains of plants, espe- 
cially Stigmarie, are of constant occurrence, and can be dis- 
tinguished by the naked eye without difficulty. 

2. Characters exhibited under the Microscope-—When a 
small chipping or fragment, about half an inch square, is 
examined as an opaque object under a power of 40 or 50 
diameters, it will be found to consist of masses of a yellow 
material, some being of irregular figure, others more or less 
rounded, imbedded in a granular matrix, varying in colour 
from a yellowish-brown, almost to black. The whole of the 
mineral appears to be composed of granules of various sizes, 
and although the part which has been termed the matrix is 
black, this also will become brown if the surface be scraped. 
The scraping can readily be done under the microscope whilst 
the fragment is being inspected ; and, curiously enough, both 
the surface of the mineral, and the minute particles scraped 
off, assume a light-brown colour. Portions of plants imbedded 
in the mineral can, by the process of scraping, be readily 
distinguished from the impressions of plants ; the former are 


36 Structure of a peculiar Combustible Mineral, 


always black and do not alter in colour, whereas the latter 
become brown, the same as other parts of the mineral. 

3. Characters exhibited by sections under the Microscope.— 
There appear to be two principal varieties of this mineral, 
one of a yellowish-brown colour, the other nearly black, these 
differences, however, are chiefly dependent upon the position 
the particular fragment selected for section occupied in the 
block. When the first variety is reduced sufficiently thin to 
be transparent, which can be done without much difficulty, it 
will be seen to consist of a tolerably uniform, yellow mass, 
whilst the darker variety is either of a rich brown, or of a 
pale-yellow colour, minutely spotted with black granules. 
When the first or yellow variety is examined with a power of 
50 or 100 diameters, it exhibits an appearance of being made 
up of a mass of transparent rounded particles or spherules of 
a rich yellow or amber colour, varying in size from the 15 5th 
to the }s5th of an inch (as shown in Plate IIL, fig. 1), whilst 
the darker variety (fig. 2) is composed of two essential ele- 
ments, one in the form of the transparent rounded particles, 
the other minutely granular, but black and opaque, and 
occupying the spaces between the yellow particles. In the 
first variety of this mineral, or that which is of a yellowish- 
brown colour in section, the yellow particles above alluded 
to are so very abundant, that they appear almost to make up 
the entire mass, whilst the dark granular element is small in 
quantity. In the second, or dark variety, the strictly granular 
opaque element is much more abundant; it sometimes occurs 
in large patches, having none of the yellow particles with it, 
but more frequently it is found in'the form of coating to 
the particles themselves. When the yellow particles are of 
large size, they always exhibit more or less of a radiated 
structure internally: this appearance, which is well represented 
in figs. 1 and 2, very much resembles that of a radiated frac- 
ture, or a species of crystallization. I shall now, for the sake 
of distinction, call all these yellow particles, or spherules, the 
bitumenoid or combustible portion of the substance, and the 
dark, granular part, I shall consider as the strictly mineral, or 
earthy ingredient. 

In some specimens there is a tolerable regularity in the size 
of the yellow particles, and in the disposition of the black 
mineral ingredient around them, so much so that an unprac- 
tised eye might, at first sight, consider its structure to be cel- 
lular: that such mistakes “ee actually been made you will 
very soon have an opportunity of learning. 

Having told you what is the usual stractare of the substance 
in question, I must beg you to understand that it matters little 


from the Coal Measures of Torbane-hill. 37 


in what direction the sections are taken; whether cut verti- 
cally, horizontally, or obliquely, there is no perceptible 
difference in the structure, and I say it without fear of con- 
tradiction, that no one, however skilled in microscopical 
observation could, from the inspection of a single specimen, 
state the direction in which the section had been made. Such 
is not the case with coal, as will hereafter be shown; a single 
inspection is sufficient to enable a practised microscopist to 
determine the actual direction of the section, whether trans- 
verse or longitudinal. 

Examination of portions of the Mineral having Plants 
imbedded in their substance.—1 have already stated that 
plants and the impressions of plants are not uncommon in this 
mineral ; of these | have made numerous sections and chip- 
pings, and most instructive they all are. The plants appear to 
be principally Stigmarie, and exhibit more or less of the three 
tissues known to botanists as the cellular, the woody, and the 
vascular ; and should one or more of these be present in any 
section, the minutest fragment even of a cell or vessel can be 
readily recognised by a practised observer; they, as it were, 
stand out boldly from the mineral matter in which they are 
imbedded, and (as shown in figs. 3 and 4) can be distinguished 
in all cases by their rich brown colour; but such plants [ not 
only consider as extraneous and not forming the bulk of the 
mineral, but such plants my investigations lead me to conclude 
rarely if ever form coal; at all events no coal that [ have yet 
examined has ever exhibited the least trace of being made up 
of such plants as are so commonly seen imbedded in this 
mineral. Even the coal lying upon this mineral, and running 
through it in every possible direction, is composed principally 
of woody tissue, and not of plants such as these. 

Examination of sections of the Mineral having Coal in juxta- 
position.—The first specimen of this kind which I had the 
opportunity of examining was brought by Mr. Bowerbank 
himself from one of the Torbane-hill pits. From this speci- 
men several sections were taken; one of them slightly mag- 
nified, is represented in Plate V., fig. 1. I regret I cannot 
show you the specimen itself, it being lodged in the Court of 
Session, in Edinburgh ; but [ have been favoured with a some- 
what similar one through the kindness of Mr. Gratton. As the 
block lay in the pit, the coal was situated below the mineral 
in the position I now hold it, and you will readily be able to 
distinguish the one from the other by the naked eye; but 
when viewed with a power of at least 50 diameters (as 
shown in Plate III., fig. 5), the smallest fragment of the coal 
that may happen to be mixed up with the mineral may be 


38 Structure of a peculiar Combustible Mineral, 


readily traced; even a part so minute as a single woody fibre 
can easily be recognised. 

In some specimens, the line of demarcation between the 
coal and the mineral is not very decided, owing to the coal 
and the plants found in connexion with it being so intimately 
blended ; in all such cases recourse should be had to the 
streak, as the best guide to distinguish them. In every part 
of the block containing coal and coal plants, the streak is 
black ; but in the smallest portions of the mineral it is brown. 
It is s curious fact, however, that in the specimen now before 
you, three kinds af structure are visible to the naked eye: 
Ist, true coal ; 2nd, a mixture of coal with a few coal plants, 
principally Stigmarie : 3rd, the mineral. When sections are 
made through the block in two directions at right angles to 
each other, the coal and the mixture of coal and plants will 
exhibit a structure corresponding with longitudinal and trans- 
verse sections of wood, but the mineral is the same in both 
sections. The yellow particles occupy all the interstices in the 
coal, and vary in shape, according to the spaces they have to 
fill (as shown in fig. 5); but whether they be elongated or of 
circular figure, more or less of the radiated structure is present 
in every particle. In such sections the vegetable tissues may 
be distinguished from the earthy ingredient by their rich 
brown colour. 

Examination of the Powder.—When the Torbane-hill mineral 
is reduced to powder, and examined either in water or in 
Canada balsam, the combustible and incombustible portions 
can be well seen; the one occurring in the form of the yellow 
or amber coloured particles before noticed, and constituting 
full two-thirds of the mass (as shown in Plate IIT., fig. 6), 
whilst the remainder is made up of minute opaque granules, 
having occasionally amongst them some which are quite 
transparent, and probably Shipegee 

Characters of the so-called Coke and of the Ash.—'Three por- 
tions of the coke of the Torbane-hill mineral, each about 
4 inches square, obtained from a gas-retort by Mr. Gratton, 
were of a greyish colour, and when scraped became perfectly 
black. ‘The remains of plants were very visible throughout 
the substance of each, and were even more distinctly seen in 
the specimens of coke than in the mineral itself before being 
subjected to heat, for every part, however minute, had 
assumed a silvery appearance. When a flat piece of the coke, 
about half an inch square, is examined as an opaque object 
under a power of 50 or 100 diameters, it presents a peculiar 
sponge-like structure ; and when contrasted with a portion of 
the mineral, it will be noticed that all the yellow particles 


from the Coal Measures of Torbane-hill. 39 


have disappeared, and a pitted appearance is produced, the 
pits being nothing more than the cavities in which the yellow 
particles were lodged, and the walls of the pits being the 
granular earthy ingredient which at one time surrounded the 
yellow particles. When small fragments of the coke are 
scraped off and subjected to a power of 250 diameters, none 
of the yellow combustible principle is present, the entire 
bulk being made up of dark granular masses. If the mineral 
be burnt in anopen fire, the ash will be nearly white; and 
when examined microscopically, no trace of the yellow com- 
bustible matter will be seen, and the granules (as shown in 
fig. 7). will be very minute, and of a light colour. These 
appearances will be constant, if care be taken to select a part 
of the mineral in which no traces of plants are visible to the 
naked eye; but if portions of plants be present, they will be 
readily recognised by their woody and vascular tissues. The 
principal distinction, therefore, between the coke of the gas- 
works and the ash is, that in the former the granules are 
larger and blacker than they are in the latter. 

From these and numerous other observations, I con- 
clude that the mineral in question is a clayey substance, im- 
pregnated with a combustible material occurring in the form 
of rounded particles of a rich yellow or amber colour, but 
whether these particles be bituminous or not the chemists 
must decide. 

What I have already stated refers exclusively to the 
Torbane-hill mineral, and no mention has yet been made of 
the structure of coal. Under this head I could enter into a 
detailed account of most of the well-known varieties of British 
coal, my knowledge of which has been principally derived 
from a careful investigation of sections made by myself and 
by my friend Dr. James Adams, of Glasgow; and I am 
happy in having this opportunity of bearing testimony to 
the correctness of the observations of Dr. Adams, upon which 
his opinions had been formed prior to my having the pleasure 
of his acquaintance. Were I now to describe these, I fear 
you would be kept here many hours; but it is the intention 
of Dr. Adams and myself, at no very distant period, to read a 
paper on the minute structure of the principal kinds of British 
coal, before the Geological Society, as we deem that the most 
fitting place for such a subject. For our present purpose, 
therefore, it will be merely necessary for me to give, in as con- 
cise a manner as possible, the results of the investigations of 
Dr. Adams and myself on this point; but I would have you 
understand that although I give youa general description of the 
structure of coal, | have with me the specimens from which 
you will be enabled to judge for yourselves whether my state- 


40 Structure of a peculiar Combustible Mineral, 


ments be correct. I am fully aware that the prevalent opinion 
with geologists and botanists is, that coal is made up of fossilized 
vegetable matter, and that this vegetable matter may consist of 
stigmaria, ferns, mosses, &c.; in short, of a great variety of 
vegetable substances. My investigations, however, lead me 
to believe that the basis of coal is essentially a peculiar kind 
of wood, and that when ferns, stigmariz, lepidodendra, and 
other plants occur in coal or its neighbourhood, they should 
be considered foreign to the coal, as these plants, before 
noticed, are to the Torbane-hill mineral. However contrary 
this may be to our preconceived notions, yet all the sections 
on the table before you, on a careful examination by an unpre- 
judiced observer, can lead to no other conclusion. I believe 
that there are in this room at the present time more sections 
of coal than any private individual has ever yet produced 
before a scientific assembly, and it is from these specimens, 
and from the study of these alone, that I am warranted in 
making this assertion. The botanist will remember that most 
of the plants generally considered as forming coal, are such 
as on section will exhibit more or less of the cellular, woody, 
and vascular tissue: now it is a remarkable fact, that most 
of the plants visible to the naked eye in the Torbane-hill 
mineral, as well as those lying in the strata above and below 
coal in general, are those which may contain spiral or other 
vessels; but, judging from all the sections of coal now before 
you, as well as chippings of others too numerous to mention, 
I am forced to the conclusion that such plants rarely if ever 
form coal, the basis of coal being essentially wood, of what 
kind, however, I will not at the present stage of the inquiry 
venture to mention, but I will state thus far, that it approaches 
more nearly to that of the Conifer than any other wood ; 
because in the Conifer, as we know them in this country, 
there are few if any vessels or ducts in the woody part 
of the trunk, but occasionally cellular tissue in what are called 
the turpentine vessels, the entire bulk being woody fibre. 
Such is the case in coal. In all the sections that I have 
examined of undoubted coal, I have as yet found no trace of 
a spiral vessel or a dotted duct, but in one or two instances 
where the woody structure has been very evident, as shown in 
Plate V., fig. 3, the fibres were evidently dotted. 

External Appearances of Coal.—These must be so well 
known to most of you, that I need not dwell further upon 
them than to particularise one or two kinds which approach 
nearest to the Torbane-hill mineral in general appearance. 
The most remarkable of these is from Methil, in Fifeshire, 
and known as the Brown Methil. So peculiar is it, that 
when scratched with a knife, the streak is brownish-black 


from the Coal Measures of Torbane-hill. 41 


in colour, somewhat resembling that of the mineral. There 
is also another variety of coal, termed the Black Methil, but 
in this the streak is black, as in all other coals. Yet the 
microscopic characters of both these varieties are very similar, 
and differ in no respect from coals generally. A curious fact, 
however, I learnt from the chemists in Edinburgh, that the 
composition of the Brown Methil came nearer to that of the 
Torbane-hill mineral than any of the other known coals did ; 
a fact which is borne out by the similarity in their external 
appearance. 

Examination of Coal by the Microscope-—If a small cubical 
block of any kind of coal be examined under a power of 
50 diameters, four of its six sides will exhibit more or less of 
a fibrous structure, precisely like that of wood ; the other two 
sides, if perfectly flat, will appear bright and polished, and 
show very little structure: these correspond to the transverse 
sections of wood. Treat the Torbane-hill mineral in the same 
way, and how very different are the results! Nearly the 
same structure will be found on all its sides, but in none is 
there the least trace of a fibrous arrangement. 

Examination of Sections of Coal by the Microscope-—lf a 
section of any well-known coal, cannel or otherwise, be 
reduced sufficiently thin to be transparent, a work sometimes 
of considerable labour and difficulty, it will be found to ex- 
hibit one of two structures, according to the direction in which 
the section has been made. These, for the sake of distinction, 
may be called the cellular and the fibrous; the first corre- 
sponding with a horizontal section, the second with a 
vertical section, of wood. If it so happen that a section 
taken at random from any specimen of coal should exhibit one 
of these structures above named, by cutting at right angles, 
the other will be found. Thus, for instance, if the first section 
should correspond to a horizontal section of wood, the cut at 
right angles to it will correspond with the vertical one ; and, 
of course, if the section be an oblique one, an intermediate 
structure would be observed. This remarkable fact is con- 
stant in all the coals I have examined, and a knowledge of it 
enables the observer to tell at once whether any section taken 
at random was a horizontal or a vertical one. How strangely 
different this from the Torbane-hill mineral! Cut that mineral 
in any way you please, and there will be little or no difference 
in appearance. The structure of the transverse sections of coal 
is so very peculiar and so characteristic, that | must briefly 
point out the means it affords of distinguishing coal from any 
other modification of vegetable tissue. The peculiarity con- 
sists in this,—that, in the midst of a black opaque ground, 

VOL, II. e 


42 Structure of a peculiar Combustible Mineral, 


numerous brown transparent rings, each having a black dot 
in the centre, are interspersed ; they appear like transverse 
sections of thick-walled cells or of woody fibres. In some 
coals they occur in close proximity to each other, as in woods 
generally: in other cases they are more or less separated, 
either by the black material before alluded to, or by a network 
of rather smaller rings, in which the central dot is absent. 
There are many coals, especially some of the common domes- 
tic kinds, in which it is difficult to recognise this structure in 
every part of the section ; in these coals a rich brown struc- 
tureless material—bituminous or not I cannot say—seems to 
be in excess, and so obscures the characteristic appearances of 
the rings. In longitudinal sections the woody fibres are 
generally well seen, and a tendency to split in the direction 
of their length (as shown in Plate V., fig. 5), may always be 
observed. Amongst the fibres may be noticed certain elon- 
gated cells, of a rich brown colour, having a dark line running 
down through the centre: these are constant in all coals, and 
when divided transversely, appear as the rings before noticed. 
Their size is tolerably uniform in many coals (as shown in 
Plate V., fig. 2). Mr. Witham was acquainted with the 
differences between a longitudinal and a transverse section of 
coal, as may be seen on referring to the 2nd edition of his 
work on the “ Fossil Vegetables of the Carboniferous and 
Oolitic Deposits ;” both the rings and the elongated cells are 
well figured, and his remarks on the value of investigating the 
microscopic structure of coal, are very excellent. The absence 
of vascular tissue in the numerous sections of coal, made both 
by Dr. Adams and myself, would lead to the supposition that 
the wood of which it is composed must approach very near to 
that of the Coniferz. 

Examination of the Powder of Coal.—When coal is reduced 
to a fine powder, and examined either in water or in Canada 
balsam, it will be found to consist principally of short opaque 
cylinders or fibres, occurring singly or in bundles, and of 
angular dark-brown plates of various sizes, probably composed 
of bituminous matter (as shown in Plate V., fig. 7); the 
remainder of the mass is made up of minute transparent 
particles of silica, with an occasional mixture of fragments 
of cells and fibres. Many blocks of coal have a fine dull 
black powder on two of their outer surfaces, which will make 
the fingers very black: this I call the charcoal layer, and in 
it will be found fragments of woody tissue of cells, and even 
of vessels. My investigations lead me to believe that this 
layer is derived from plants which existed at the same time 
as the coal-wood, but were not capable of being converted 


from the Coal Measures of Torbane-hill. 45 


into true coal, but having been subjected to a great heat, 
their remains are left as a species of charcoal. Some speci- 
mens of the Torbane-hill coal have a large amount of this 
charcoal upon their upper and under surfaces, and in it, vessels 
of various kinds will occasionally be found, although such 
vessels do not occur in the solid coal itself. 

Examination of the Ash of Coal—Vhe brown ash of coal, 
with the exception of particles, probably of silica, is almost 
wholly composed of vegetable remains, some of which pro- 
perly belong to the coal itself, whilst others are derived from 
extraneous plants which have been mixed up with it. Every 
kind of tissue which has been described as proper to the coal 
may be met with in the ash, when not too much burnt. The 
remains of woody fibres and cells are the most common con- 
stituents, but flat, very opaque, irregular masses, such as are 
shown in Plate V., fig. 4, and which evidently correspond to 
portions of transverse sections of wood, are frequently found. 
Portions of siliceous cuticle, probably of grasses, as shown 
in fig. 6, from a drawing by Dr. Adams, are far from being 
uncommon. In short, when the indications of the woody 
structure of coal are very faint in sections, they are well ex- 
emplified in the ash. Sections of Welsh Anthracite (which 
I believe to be a fossil coke) are most difficult to obtain, and 
when made, afford very unsatisfactory evidence of vegetable 
structure: when, however, the ash is examined, the presence 
of woody tissue is unquestionable. 

The Torbane-hill mineral has been most carefully examined 
by my friend Dr. Adams, and as his investigations were car- 
ried on independently of mine, it will be satisfactory that you 
should be made acquainted with the conclusions he has ar- 
rived at after a laborious series of examinations. ‘They are as 
follow :— 


“¢ The most interesting example which could be adduced, illustrative of 
the differences in essential characters, as demonstrated by the microscope, 
between substances supposed by commercial men to be identical, is found 
in the Torbanehill mineral, known also by the name of Boghead coal. In 
the lawsuit previously alluded to, much of the scientific evidence regard- 
ing this mineral was of a very conflicting character, so much so that the 
court virtually set aside the scientific evidence, and decided on the legal 
merits of the commercial bargain. 

‘The importance of the interests involved, and the high character of 
the witnesses examined, have made this trial very celebrated; and it is 
from an excusable desire that the grounds of the opinion I expressed at 
the trial should be understood, that I now seek to place them on record. 
I will, however, confine my remarks to a very short summary of my 
observations made upon the Torbanehill mineral, leaving a fuller detail 
with my friend, Professor Quekett, who gave joint evidence with me, and 
with whom I have discussed and investigated the whole subject of my 


e2 


44 Structure of a peculiar Combustible Mineral, 


present communication with a most pleasing and perfect accordance of 
observation and opinion. 

“ The following are the principal results :— 

“], A very thin section of the Torbanehill mineral, when viewed by 
transmitted light, has a pale-yellow colour, is semi-transparent, and, with 
the exception of very slight variations in the depth of the colour, probably 
dependent on the varying thickness of the section, it appears to be a 
uniform homogeneous mass. The same appearance is constantly presented 
notwithstanding that the sections are taken in various directions. While 
this is the usual appearance of what may be termed the average specimens, 
viz., of portions taken from the centre of the block (or seam), yet, in 
sections taken from near the outside, or lower portion of the seam, I find 
a quantity of small opaque particles (evidently earthy matter) in the form 
of a fine powder, scattered through the yellow-coloured medium forming 
the mineral. In such specimens the transparent yellow substance forms 
irregular rounded granules, and the opaque powder is either sparingly 
diffused over, or forms an outline or partition, more or less perfect, around 
the exterior of the yellow granules. These granules vary much in size, 
being as small as 1-4000th of an inch, and of every intermediate size 
from that up to 1-200th of an inch in diameter. 

‘¢ Tn sections taken from the outside, as above described, I have observed 
oceasional patches of opaque material of every irregular form, and which 
I could not liken to any other substance, unless I spoke of them simply 
as specks of dirt. In the same sections I have also found stalks of plants 
and fragments of wood. These opaque patches and vegetable fragments 
are always distinetly isolated ; that is, they do not in any way resemble 
or form part of the substance of the mineral, otherwise than by being 
involved or contained in it, and their presence, therefore, can only be 
considered accidental. 

“II. When reduced to a fine powder, and examined under water, all 
the particles of the mineral have a clear, and generally a sharp outline, 
are of an irregularly rounded form, and may be described as of a uniform 
granular appearance. About 7-10ths of the granules are very translucent, 
and of a light amber or yellow colour. About 2-10ths of the particles 
(also translucent) partake more of a flat, angular shape, and are quite 
colourless, probably consisting of siliceous matter. The remainder of the 
powder consists of dark semi-opaque particles. 

‘“< In specimens of powder taken from an outside portion of the mineral, 
there is observed a larger proportion of the semi-opaque particles, together 
with the occasional appearance of vegetable stalks, rough fibrous frag- 
ments, and delicate fibrils of microscopic plants. With these special 
exceptions, the powder gives no trace whatever of organic structure. 

“ IIT. The ash of the mineral, when examined under water, presents a 
considerable quantity of the colourless particles already described, lying at 
the bottom of the fluid, while a filmy particle of transparent particles floats 
on the surface. No trace whatever of organic structure is here observed. 

** Polarised light does not in any way affect the appearances of the 
mineral. 

I have, in consequence of these investigations, a firm conviction of the 
non-identity of the Torbanehill mineral with coal, setting aside those 
differences which may be found to exist under mineralogical, geological, or 
chemical investigation. I cannot conceive how the evidence of Amorphisin 
in the one case, and of intimate vegetable composition and of regular 
structure in the other, can be explained away, or any other view than 
that of non-identity of physical structure. In coal we find a well- 
characterized organization, or regular arrangement of its component parts 


from the Coal Measures of Torbane-hill. 45 


so distinctly peculiar, that I should question the competency, at least, of 
any party who, after comparing the microscopic appearances of the two 
substances in question, could hint at a resemblance. The Torbanehill 
mineral, on the other hand, is as thoroughly devoid of organic structure, 
or of any rezular arrangement of its compouent parts, as is a mass of 
jelly or a conglomerate of masons’ mortar.” 


I will now, in the third place, proceed to read the evidence 
given by the witnesses for the pursuer and the defender. 


Professor QuEKET?T.—Hxramined by Mr. MACFARLANE. 


You are one of the Professors in the Royal College of Surgeons in 
London ?—Yes. 

What chair do you occupy ?—The chair of Histology. 

What is the object of that study?—An examination of the minute 
tissues or structure of plants and animals. 

I believe you have devoted a great deal of study and attention to that 
subject ?—Yes, for the last twenty years. 

You have published a catalogue of the preparations in the College of 
Surgeons of London, descriptive of the various tissues ?—Yes. 

And you have yourself a very extensive collection ?—Yes, I believe the 
largest in Europe. 

You conduct your investigations with the aid of the microscope ?—Yes. 

And have you made careful investigation into the structure of the 
various coals, as well as other minerals >—Yes. 

Have you in this way had occasion to examine the most of the known 
coals in England and Wales ?—Yes, about seventy varieties. 

Have you also examined varieties of Scotch coal ?—Yes. 

What have you discovered to be the tissue of coals ?-—They show us a 
woody tissue. 

Have you found structure of that description in all the varieties to 
which you have referred ?—AlIl the varieties of coal. 

More or less distinct, I suppose ?—Yes. 

Now, have you examined the Torbanehill mineral ?—Yes, in every 
possible way microscopically. 

Were specimens of the mineral delivered to you?—Yes, some time ago. 

By whom ?—By Mr. William Forbes and a Mr. Rettie. I have the 
specimens here. 

Now, did you subject those specimens to a very careful examination ?— 
Yes, very careful. 

You tried them in every possible way, and repeatedly ?—Yes, and 
repeatedly. g 

Did you make a great many sections out of them ?—Yes, an immense 
number. 

ad as to give you every possible opportunity in tracing their structure ? 
—Yes. 

What result did you come to?—That the Torbanehill mineral is dif- 
ferent from anything that I ever saw in my life before. 

Did you discover any trace of organic structure ?—Yes, when plants are 
accidentally mixed with it. 

You were enabled to ascertain when it was so ?— Yes. 

Perfectly ?—Perfectly. 

But in the substance itself ?—No structure—that is, what the micro- 
scopists would term an organic structure. 

Is it different in that respect from all the varieties of coal you have 
examined ?—Decidedly so. 


46 Structure of a peculiar Combustible Mineral, 


Did you get illustrations P—Yes, I have illustrations. (Produces same.) 
I think you will come to a better understanding of the thing from those 
illustrations than from the specimens. 

Explain what that is (referring to illustration shown to the jury).—This 
is a section of the Torbanehill mineral, or rather a granular section, and in 
it you will observe some yellow matter that burns—whether bituminous or 
resinous you must go to the chemists for. ‘The black part is the strictly 
mineral part. 

What is the mineral matter to which you refer ?—It is the dark granular 
matter. 

Lord-President.—I understand that these illustrations show the bitumen 
and the mineral at different places ?—Yes, my Lord. 

Mr. Macfarlane.—Now, then, do the illustrations of your coal investi- 
gations exhibit a different appearance ?—Decidedly. 

Now, you say the mineral substance there is granular, is it so in the 
coal ?—Not at all, except when visible to the naked eye. In coal, you 
can see mineral structure by the naked eye, but to that I do not allude ; 
but under the microscope you can tell that is a totally distinct thing from 
the coal itself. What I mean is, that in specimens of coal you can often 
see crystallized matter with the naked eye. 

Is that extraneous ?P—I would say so. 

But when subjected to the microscope ?—It exhibits a totally different 
structure. It is not granular; it depends entirely on which way the 
specimen of coal is cut. If cut in one direction you will either see a 
cellular or fibrous appearance. 

Indicative of what ?— Woody tissue. 

You have, I suppose, made sections in all the specimens of the Torbane- 
hill mineral—in all the various ways you have made sections of the coal ? 
—Yes. 

And you have found in all the different sections a decided difference, 
showing them in your mind to be different, substances P-—Certainly. 

Then, judging from all your experience and investigation, do you con- 
sider this 'Torbanehill mineral to be a description of coal or not ?—Certainly 
not. 

Have you any illustrations of coal there >—Yes, I have a most remark- 
able illustration—perhaps the jury will understand better by this than 
anything else. I have here a section of the mineral and coal in juxta- 
position; this has been cut by Mr. Bryson, lapidary, and you will be 
enabled to see whether coal or mineral. The woody section is shown by 
the dark colour, the mineral by the other. 

Are those illustrations of longitudinal, or transverse sections, or what 
sections >—That of coal is longitudinal, and of the mineral it is supposed 
to be the same, because they are in juxtaposition. 

Suppose a transverse section—what differenceP—In the Torbanehill 
mineral a section at right angles would present precisely the same cha- 
racter, but the coal would present another character, that character being 
shown in this lower drawing (exhibiting it to the jury). You will notice 
that the coal runs through that mineral. You can trace it by its minute 
tissue. 

You examined some of the Scotch varieties of coal?—Yes, many 
varieties. 


Did you examine the Methil?—Yes, of two kinds, I believe known by - 


the names of the brown and the black. 
Did you discover vegetable structure there ?— Yes. 
Decidedly in both ?—Decidedly in both. 
And in that respect different from this Torbanehill mineral ?—Certainly. 


i et pt 


from the Coal Measures of Torbane-hill. 47 


You mentioned at one time that you had observed the presence, in some 
of those coal specimens, of fossil plants ?—Certainly. 

Could you see them with the naked eye ?—Yes, in those specimens of 
the Torbanehill. 

Have you seen them in coal in the same way ?—Yes, but I consider 
them extraneous or isolated examples. 

Cross-examined by Mr. Neaves.—Is the structure of coal uniform in 
general?—It is so tar uniform that the various transverse sections are 
uniform, and so are longitudinal. 

Equally visible in all places of the coal p—Yes, in all places, except, as 1 
have stated before, where you have mineral that is foreign to the coal. 
ee mineral matter do you allude to?—The chemists must decide 
that. 

You only speak to appearances ?—Yes. 

And the same formation in all?—Yes; the plants differ; I believe there 
are two kinds of plants or tissue that essentially form coal. 

But they present the same appearance ?—Yes, but those plants are not 
traceable in the same specimens of coal]. ‘That in the neighbourhood of 
Glasgow may be different from the coal found in the neighbourhood of 
Edinburgh. 

Can you distinguish the one plant from the other ?—Yes, in the longi- 
tudinal section. 

And you never found any portion of any coal without exhibiting the 
same permanent structure P—Certainly not. 

Where did you get that specimen you showed us of the two coals 
together ?—That was taken by Mr. Bowerbank from the mine two or 
three days ago, and the drawing was taken from a magnified representation 
of one of the sections. 

Lord President.—Let us take down what those specimens are if they 
are to go in, but I thought they were to be taken away by the witness. 

Dean of Faculty.—No. 25 represents that yellow matter of which the 
witness spoke ; No. 26 is the drawing of that highly-magnified section ; 
Nos, 28 and 29 are the specimen and the drawing; and No. 27 is the 
appearance presented by the two different sections of coal itself, the one 
longitudinal and the other transverse. 

Witness.—There is one thing I would wish to state, this—I came here 
to speak the truth, and it may be testimony for or against my evidence, 
when I say that all that which may be supposed like vegetable structure 
in the Torbanehill mineral disappears when the structure is thin. 

Dean of Faculty.— When you speak of that which appears as vegetable 
structure, you mean those isolated fossil plants?—Yes. 1 would also 
allude to the fact that a book was published in this city twenty years ago, 
by Mr. Witham, of specimens made by Mr. Nicol; and this was the first 
representation of this vegetable structure. 


Dr. James Apams.—Lxamined by Mr. MAcFARLANE. 


You practise as a medical man in Glasgow ?—I do. 

Have you devoted a good deal of time and study to observations by the 
microscope ?—I have. 

For a considerable time back ?—For many years. 

eure you subjected to examination by the microscope various minerals ? 
—lI have. 

Extensively ?—Extensively. 

Varieties of Scotch coal ?—Yes, a great many. 

Most of the known varieties ?—-Most of the known varieties, 

Have you examined the Torbanehill mineral ?—I have. 


48 Structure of a peculiar Combustible Mineral, 


Recently ?—Recently. 

And did you subject it to a very careful investigation ?—Very careful. 

In various forms p—Yes. 

Now, will you tell me what those Nos. of process are, No. 259 to 263, 
both inclusive ?—259 represents sections of various specimens of the Tor- 
banehill mineral, as seen under the microscope. 

From the centre of the same, from the outside or bottom, and also from 
the outside of block ?—Yes. 

What is the next No. P—260, representing two sections of coal, termed 
to me cannel coal—Duke of Hamilton’s cannel coal; the one represents 
what I have termed a longitudinal section, and the other a transverse 
section, drawn by myself. 

The next No.?—Is 261. This represents.a drawing of what was 
termed to me Lesmahagow, Ferguson’s cannel coal—two sections drawn 
from specimens made by myself; but the drawing made by an artist 
named Donald, of Glasgow, under my eye. 

And you have no doubt they are correctly done?—No doubt; very 
faithfully made. 

The next No. ?—262, representing sections of—Ist, what is termed 
Jordanhill cannel coal. The one is longitudinal of Jordanhill, the other is 
a transverse section of a coal called Cowdenhead, given tome. This one, 
2638, which represents three drawings—two transverse and one longi- 
tudinal; a transverse section of Jordanhill cannel coal, drawn by a 
medical gentleman of the name of Risk, under my eye, a faithful delinea- 
tion ; the other is a drawing of cannel coal procured from the Glasgow 
Gas Works, called Knightwood coal; and there is also a longitudinal 
drawing of Knightwood. ‘Those three drawings were made under my eye 
by Mr. Risk. 

Did you subject the powder of the Torbanehill mineral to the micro- 
scope ?—I did. 

Having applied a little water ?—Yes. 

What did you discover to be the particles ?—Those particles have a 
clear granular shape, they are of an irregular rounded form, and I say 
may be described as exhibiting an uniform granular appearance. 

Any further description ?—About 7 of those granules are very translu- 
cent, and of a light-amber colour. About %, also translucent, partake 
more of a flat or angular shape in their outline, and are quite colourless ; 
and there are a few particles of a dark or semi-opaque matter. 

Now have you examined coal specimens in the same way ?—I have. 

What were the results ?—They differed very materially ; the particles 
of cannel coal which I took as being the more compact coal, are found of 
various sizes, and in form generally flat, angular, or oblong, with fibrous 
character; the edges generally rough and as darkly opaque as in the 
centre. 

Have you examined the ash of the Torbanehill mineral p—I have. 

When you said that the coal particles were of different sizes, were the 
particles of Torbanehill mineral of various or the same size?—When I 
examined them under a high power I found the Torbanehill to be also of 
various sizes. 

You examined them with the aid of a microscope carefully ?—Yes. 

What results?—I found it very difficult to describe the appearance, 
because it seemed to consist of a film or congeries of structureless particles, 
I got nothing tangible almost to lay hold of. I consider most of those 
consisted of the colourless particles which I have mentioned as having been 
found in the powder, viz., the flat, angular, and perfectly transparent 
particles. 


from the Coal Measures of Torbane-hill. 49 


I understand, Doctor, when you say perfectly structureless, that there 
was no organization ?—No organization ; they have form. 

No trace of vegetable origin ?—None. 

Nor the coal ash?—In the coal ash examined under water, I found 
abundant remains of vegetable structure, examined in the same way. 

Woody tissues in the coal ?—Yes. 

Did you conduct your investigation of the ash of the Torbanehill 
mineral and of the coal both in direct and transmitted lights >—By both. 

And with the results which you have described ?—Yes. 

Were they the best, most approved instruments ?—They were. I have 
used various instruments of all kinds, but I have used the best and most 
recent construction. 

What were those ?—Those were prepared by two of the most eminent 
London opticians, Mr. Ross and the firm of Smith and Beck. 

What conclusion do you arrive at in regard to this Torbanehill mineral, 
_ keeping in view your investigation of the sections, of the powder, and of 

the ash ?— That the two substances are totally dissimilar. 

That the Torbanehill is a different substance from any coal with 
which you are acquainted >—Yes. 

Cross-ecamined by Mr. Neaves.—Are you in practice in Glasgow as a 
physician P—I am. 

Have you marked the magnifying power of the instruments used on 
those specimens ?—I have. 

When did you first see this mineral?—I think on 15th January last 
year. 

Had you never seen it before ?—Never to my knowledge. 

You had previously been in the habit of examining coals ?—I had. 

And had seen all the caunel coals ?—Not then. I have since examined 
them. 

What coal had you seen when in the practice of examining before ?— 
Chiefly domestic coal. 

For many years ?—For several years. 

With any particular view >—None. 

The body and ash of domestic coal ?—Yes. 

You always see the woody structure in the ash ?—Always; I have 
never failed. 

And in the coal ?—Do you mean the sections ? 

Yes—I have never met with a piece of coal that had not those 
appearances. 

Do you give it a name ?—I call it a fibrous section, from appearing like 
a bundle of fibres in one direction. I give it longitudinally, because it 
gives me the idea of length, and annular, that is, composed of rings, 
when seen in a cross cut with a longitudinal. 

But are equally distinct in the same coal always?P—Not equally 
distinct. 

Not equally distinct in all coals nor in the same coal ?—No, but remain 
always distinct in every coal. 

Re-examined by Mr. Macfarlane.—Have you been at Torbanehill ?—Yes, 

And made specimens ?—Yes. 

Did you examine from those specimens ?—Yes. 

Fair or average specimens of the mineral ?—I took them just as they 
were raised from the pit, and examined them from the centre, outside, 
and every way I could possibly conceive. 

Your observations have been more recently directed to cannel coal ?— 
Yes. 

Can you give me the names ?—lI believe I have examined about forty or 


50 Structure of a peculiar Combustible Mineral, 


fifty different specimens, as far as I know, but I can give the names o 
different coals that I tested. 

Just give us a few ?—These were Capeldrae, Wemyss, and Pirniehill, 
&e. 

Your investigations had been previously chiefly directed to the ordinary 
coals ?—Yes. 

Is it more difficult to trace the organic structure in the cannel coal than 
in the ordinary domestic coal ?—It is. 

Perhaps requires more skill and practice ?—Yes, in conducting the 
investigation into the cannel coal. 

What is the reason of that?—The reason I believe to be, that the 
structure is much more compact in the cannel coal, and the section requires 
to be made exceedingly thin, and it is very difficult to procure that con- 
dition, from the excessive brittleness of the material, and also intense 
opacity, and containing particles of hard matter, which frequently tear 
out the specimens. 


Mr. BowERBANK.—Faxamined by Mr. MACFARLANE. 


Mr. Bowerbank, you live in London P—I do. 

You have given a good deal of your time and attention to microscopical 
observations ?—I have for these twenty-five years past. 

You are a fellow of the Royal Society ?—I am. 

You were lately president of the Microscopical Society of London -— 
I was. 

And you have written on the subject, I believe ?—I have. 

Have you made a great many examinations, with the aid of the micro- 
scope, of mineral substances P—I have. 

Of various descriptions of coal ?—I have. For many years, the subject, 
simply as a natural-history subject, was much inquired into, 

And you have turned your attention to it ?—I have. 

And have for several years been taking observations, with the micro- 
scope, of coal substances p—Yes. 

Have you been at Torbanehill P—I have. 

Recently ?—Yes, recently. 

And you obtained specimens of the mineral that is working there ?—I 
did. 

And subjected them to examination ?—I have. 

Did you give a specimen last week to Professor Quekett ?—I showed 
him a specimen, and he desired to possess it for examination. 

And did you give some specimens to Dr. Adams ?—I did. 

What has been the result of your examination of coal substances ?— 
Every coal which I have examined, either by sections, or by external 
characters, or by the examination of the ash, has convinced me that it is 
an essential character of coal that it should be composed principally of 
organized vegetable substances and bitumen. 

Lord President.—Of what, did you say ?—Of organized vegetable 
carbon and bitumen principally. 

Mr. Macfarlane.—With a little earthy matter ?—Yes. 

I think you said these examinations were of the sections of the sub- 
stance, and of the ash as well ?—Of the sections of the coal matter, and of 
the ash as well. The practice generally adopted in examination is, first 
to observe its ordinary characters, and next its sections, so as to develop 
its structure. 

Have you pursued the same mode of investigation in regard to the 
Torbanehill mineral ?— Exactly. 

And with what result ?—I have found no organic structure in it, 


from the Coal Measures of Torbane-hill. 51 


although I have examined it by powers varying from 40 or 50, up to 
very nearly 700 linear. I have also examined the ash with great care ; 
and I may say that as to almost every specimen that has passed through 
my hands identified, and others as well, in no case have I found any 
indications of vegetable structure in the ash. 

Then the results of your examination of the coal, and of this mineral, 
are very different ?—Quite opposite. 

I suppose, Mr. Bowerbank, you have used the best instruments ?—Yes, 
Sir, I believe there are no better to be procured. Indeed, unless they 
were instruments of a high optical character, they would not develop the 
minutest portions of the tissue satisfactorily. 

Who are the great London makers ?—Ross, Powell and Smith, and 
Bett (or Beck). 

You have examined, I suppose, different varieties of shales, have you ? 
—To a very considerable extent. 

Any traces of organic structure in them ?—Not in the body of the 
shale itself, but a great intermixture of isolated plants. In fact, in coal 
shales isolated plants form a considerable portion of them. 

We have had the word ‘ amorphous’ used frequently, Mr. Bowerbank. 
Can you explain its meaning ?—lI understand an amorphous mass of 
that description to be a mass without crystallization—a mass which 
would cleave in any direction without any determinate arrangement. 
For instance, I would say a sandstone, although formed of granulated 
masses, is still an amorphous mass, as there is no determinate arrange- 
ment. 

Where there is organic structure, the word amorphous would not, of 
course, apply P—Not to the structure itself, but it may apply to the 
medium in which that structure is imbedded. 

Cross-examined by Mr. Neaves.—Where did you get your specimens ? 
—Some from Torbanehill pits, which I visited within the last week. 

And adjoining properties ?—And some from the adjoining properties as 
well. 

What property was that ?—Bathgate pit, and another pit. I also 
received verified specimens sent from the country to request an examina- 
tion of them. 

You first saw the mineral there P—I first saw the mineral at Queen- 
wood College, some time ago. 

Some months ago ?—About three months ago. 

Re-ewamined by Mr. Macfarlane.—Among other coals have you 
examined various cannel coals ?—Frequently. 

And the statements you have made have had reference to them as well 
as to others ?—The specimens which I have examined of the cannel coals, 
vary very considerably in character from this new mineral from Tor- 
banehill. 

You discovered the vegetable origin of the structure in them ?—Oh, 


yes. 
This closes the evidence of the microscopists on the 


pursuer’s side. I will now proceed to read that given on the 
side of the defender. 


Professor J. H. BALFour.—Haxamined by Mr, NEAVEs. 


You are Professor of Botany in the University of Edinburgh ?—Yes. 
And I understand that you have devoted attention not only to the sub- 
ject of botany as concerns existing plants, but also to fossil botany ?—Yes. 


52 Structure of a peculiar Combustible Mineral, 


Is that a part of the course that you teach ?—Yes. 

In the course of teaching that class, are you in the habit of examining 
mineral substances with a view to noticing their structure P—I examine 
fossil plants. I have a large collection of specimens of fossil plants. 

Have you been in this case shown some specimens of different minerals 
with a view of examining them ?—Yes. 

What were they ?—I have seen specimens of the 'l'orbanehill coal, the 
Methil coal, the Capeldrae coal, the Lesmahagow coal, and several other 
parrot and other common coals, 

Did you visit the ground at Torbanehill ?—Yes, I went to the pits and 
examined the coal, and brought specimens from the place. 

Did you visit the Methil pit >—Yes. 

And got some specimens from Methil ?—Yes, out of the pit. 

And where did you get the other specimens that you refer to?—I got 
them from various sources. Some were sent me authenticated by Mr. 
Russel, some were given me by Dr. Maclagan, also by Dr. Redfern, Dr. 
Aitken, and Professor Harkness. 

Did you make sections of these minerals with a view to a microscopical 
investigation of them P—Yes. 

Did you make such a variety of sections as to enable you to judge in all 
directions >—Yes, so as to judge fully of the structure. 

Now, from that examination, are you able to say whether you dis- 
covered in these specimens traces of organic structure P—Certainly organic 
structure. 

In all the specimens ?—In all the specimens more or less. 

Now, in the Torbanehill mineral did you find marks of organic struc- 
ture ?—Certainly. 

And in the Methil ?—And in the Methil. 

Was there any difference, or any resemblance, between the appearance of 
the Torbanehill mineral and the Methil mineral?—A remarkable similarity. 

Was there some Lesmahagow coal ?—Yes. 

And some Capeldrae also ?— Yes. 

And I think some Kinneil coal ?—Some Kinneil. 

Which is a cannel also ?—Yes. 

Did you take the assistance of Dr. Greville?—I took his assistance in 
delineating what we saw under the microscope. 

Did you see his delineations ?— Yes. 

Did they appear to you to be successful ?—Most correct, I think. 

You believe coal generally to be a vegetable formation, I suppose ?— 
Certainly. 

Of what species of plants is it generally supposed to be composed P—The 
coal plants are numerous. We have, in the first place, a mass of ferns, 
stigmarias, sigillarias, lepidodendrons, calamites, and various other genera. 

The ferns supposed to form coal-beds are very gigantic ferns compared 
with the present ferns ?—They are tree ferns. 

Is it a cryptogamic plant P—Yes. 

In such plants, what is the particular appearance or structure you 
would expect to find ?—In all these plants, as well as in other plants of a 
woody stem, we have cells and vessels ; but in the tree ferns we have a 
structure which may be said to be pretty regular, which is called scalari- 
form, or ladder-like, from the bars visible upon it. They are vessels or 
tubes. 

Did you see in the Torbanehill coal appearances that seemed to you to 
indicate cellular structure ?—Certainly. 

No doubt of that ?—No doubt of that. 

And also some appearances indicative of scalariform structure ?—Yes. 


from the Coal Measures of Torbane-hiil. 53 


The cellular appearances more generally diffused than the other ?—Yes, 
much more generally. 

Do you consider you have in that way evidence of the vegetable compo- 
sition of the Torbanehill mineral ?—Yes, certainly. 

And of the same character generally as the other cannel coals that you 
examined ?— Precisely. 

{Here several drawings were handed to the witness, and he was asked to 
explain them. 

In the first drawing, which was of the Torbanehill mineral, witness 
stated the sections showed the vegetable structure, and also the scalariform 
vessels, with the bars upon it, very distinctly. ] 

Is that the kind of structure that is seen in modern tree ferns ?—Yes, 

The next drawing exhibits three sections,—the Lesmahagow, the Capel- 
drae, and the Torbanehill coal,—showing precisely similar structure. They 
are a little different in colour, but the same in structure. There are also 
sections of the Torbanehill and Methil in the drawings, showing the same 
appearance and structure in both these. Another drawing of the separate 
individual shales shows distinctly the appearance of separate cells, both in 
the Torbanehill coal, in the Lesmahagow coal, and in the Capeldrae coal. 
And, in fact, we find these in various other coals. 

The cell is the base of the organic structure of these vegetables >—Yes. 

It is the accumulation of cell upon cell that builds up the structure p— 
Yes. 

Judging microscopically, then, and also with your knowledge of fossil 
botany, would you draw the inference that the Torbanehill was of the 
same, or of a different class of substances from the other cannel coals that 
you have mentioned ?—The same class as of the cannel coals I have seen. 

The only difference, I understand you to say, is the difference in the 
tinge of colour ?>—Yes, and that occurs in many coals. 

You don’t think that essential in deciding the question ?—I do not. 

Cross-examined by the Dean of Faculty.—These observations are made 
upon a thin section ?—Yes. 

Who made the sections ?>—They were made by Professor Harkness, Dr. 
Aitken, Dr. Redfern, and Mr. Glen. 

Would you mark upon each the name of the gentleman who did them ? 
—Yes, to the best of my recollection. 

{Here witness marked each section as requested. } 

Have you yourself been accustomed to make such sections ?—I have 
made sections for the microscope. 

Have you much practice with the microscope ?—Yes, it is part of my 
course. 

In reference to existing plants P—Yes, and also to fossil plants. I have 
a large collection of fossil sections. 

With regard to this drawing here [holding up one of those previously 
described by witness], that represents the impression of an individual fossil 
plant ?—That represents only a portion of a plant, the vascular part of the 
vascular tissue of a plant, approaching nearly to the scalariform tissue. 

Do you mean that the tissue is there, or the impression on the plant -— 
The tissue is there. 

In this other portion of the seam, then, which is coloured brown, you do 
not observe any structure ?—I did not examine particularly. 

But does this represent what you saw on that occasion ?—Yes. 

Then there is no appearance of structure there ?—I cannot say. 

There is no structure represented there >—No. 

All that you found in this particular section is the representation of part 
of a fossil plant ?—Yes. ” 


54 Structure of a peculiar Combustible Mineral, 


Part of an individual plant apparently ?—Part of an individual plant 
probably. 

Do you know from what portion of this seam of Torbanehill mineral this 
slice representing the upper drawing is taken P—I do not know the portion 
of the seam. 

Do you know the portion of the seam from which any of them were 
taken ?—I have only seen the specimens. They seem to be the ordinary 
appearance of the Torbanehill mineral, and quite the usual appearance of 
the coal, so far as I saw. 

Here the Dean of Faculty took up another drawing, and asked witness 
if he saw anything similar‘to that ?—I saw appearances similar to that. 

Have you represented them ?—Represented them so far in some of these 
sections, only the dark colour between makes a: difference in the appear- 
ances. 

Lord President.—Is that in the Torbanehill mineral >—Yes. 

Dean of Faculty.—Did you see anything like that [showing witness 
another drawing, No. 25]?—Something approaching to this. It wants, in 
some respects, the regularity of the structure I have seen in the other. 

Shown No. 26, another drawing, and asked if he had seen anything like 
that ?—This also approaches to what I observed, but wants the definiteness 
and regularity of the structure I saw. 

Did you see anything like that [showing No. 28, another drawing] ?— 
Yes, the yellow part is more like what we saw in the general structure. 

What power did you use in making these observations ?—They are 
marked in diameters ; two of them were 200, and the other 70. 

Have you ever examined shales in this way ?—I have looked at one or 
two shales. It is not so much in my way as plants. 

Do you find marks of fossil plants in them ?—Yes, they occur; but the 
structure is different in them. ‘They have not the same marked definite 
form I have seen in the others. 

I understand that\in these you represent both the transverse and the 
parallel sections ?—Yes, we have taken them in two directions. 

Which are the transverse P—The three upper are the longitudinal, and 
the lower the transverse or horizontal. 

What do you mean by horizontal ?—By horizontal we mean cutting off 
the ends of the vessels. 

That is to say, you learned that from the gentlemen who made them ?— 
I have examined sections. 

You did not see the sections made >—No. 

Then, of course, you could only get the information from those gentle- 
men who made them ?—Yes. 

Are the three upper cut along the stratum, as it were, off the top of the 
stratum as it lies?—I am talking of them as regards the appearances we 
see in the microscope. Judging from ordinary structure, in the one case 
we cut the ends of the vessels ; in the other, we cut along the line longi- 
tudinally. 

Lord President.—The three upper are cut along the line of the vessels, 
and the three others are cut across the line of the vessels. 

Dean of Faculty.—Do I understand you to say that you were told they 
were cut in this way, and that that is the ground of your saying so; or do 
you form your opinion by the appearance they present ?—I was of course 
told so; and on looking at them, I should say they are so cut. 

Then it is from both these reasons that you say so ?—Yes. 

Did you examine any part of the ashes of this mineral with the micro- 
scope ?—No. i 

Did you ever examine"the ashes of coal with the microscope ?—No. 


from the Coal Measures of Torbane-hill. 55 


Did you use direct or transmitted light in these examinations ?—I used 
generally transmitted light, but I also viewed some specimens by direct 
light. 

Re-examined by Mr. Neaves.—There are several drawings here. Did 
you examine a great many more cuttings than these drawings?—A great 
number. 

How many more, do you know ?—I cannot tell the number of the sec- 
tions of Torbanehill ; at all events, some eight or ten, besides sections of 
other coal. 

And then made a drawing of these >—Yes, as being average specimens. 

Did you see some of these sections made P—Yes, these were the sections 
made under my direction by Mr. Glen. 

The Methil section?—I cannot say I saw it made in the sense that 
I saw the whole process gone through, but it was done for me, by my di- 
rection, from a piece of Methil coal. 

Lord President.—Did you see Mr. Glen make some of the sections ?—I 
should rather say that the sections I allude to were made under my direc- 
tion, and were authenticated by me at the time. 

Mr. Neaves.—In the other sections of the Torbanehiil mineral which 
you have examined besides this, did you find the same appearances p—The 
same appearances. 

I forget what you said as to this yellow part of No, 28 ?—I considered 
that to be a cellular structure. 

The yellow part included ?—Yes. 

This cellular tissue is a magnified appearance of the separate individual 
cells >—Yes. 

With the view of showing that they were at larger power ?—These are 
cells which occur in these coals, and they are separated the one from the 
other. We took magnified drawings of them. 

Occurring at Boghead ?—Yes, and on the others. 

And besides showing those things, you formed an opinion of what they 
were ?—Yes. 

That they were the indications of vegetable cellular structure ?— 
Certainly. 

Lord President.—That is, the appearances in the mineral seams P—Yes. 

Mr, Neaves.—Including the Torbanehill p—Yes. 

And of that yellow part of the representation of the Torbanehill 
mineral ?—I believe it to represent vegetable cells. 

In these plants I suppose the structure is but imperfectly understood ? 
—I may say we do not know it so completely as we know all the plants 
of the present day. 

The cells may be longer or shorter >—Yes. 

They vary in their form ?—Yes. 

And that may affect the longitudinal appearance of the cells ?—Yes. 

I do not understand you to say that this is the mere impression of a 
foreign fossil, but the actual structure of the mineral at that place ?— 
Certainly. 

Dean of Faculty.—The individual plant is there lying in the mineral ? 
—The structure of the plant—not the entire plant. 

A part of a fossil plant is seen there ?—Yes. 

Mr. Neaves.—Forming a part of the coal ?—Yes. 

Dean of Faculty.—I understand, Dr. Balfour, that there is a part of 
the fossil plant here lying imbedded in something or other ?—It is a quite 
dissimilar part as regards the appearance. 

The plant must be there in order to give it that appearance ?P—It must 
be the structure appearing so distinctly as to be seen there. 


56 Structure of a peculiar Combustible Mineral, 


Very well; a plant is lying here upon another thing, which is here 
represented by a dull-brown colour ?—Yes, a part of the plant. 

Mr. Neaves.—What did you say ?—That that is part of the structure 
of a plant which is lying there in the mineral. When you make a 
section of the mineral you come upon this, showing you that there was a 
plant. 

: At that part the mineral consists of that plant ?—Yes. 

Dean of Faculty.—You have seen fossil plants in stone quarries ?—Yes. 

Mr. Neaves.—You do not consider that an example of such an appear- 
ance r—No. 


Dr. Reprern.—Examined by Mr. NEAVEs. 


Dr. Redfern, you lecture on subjects connected with the microscope in 
connexion with the University ?—Yes; and teach the use of the micro- 
scope. 

You are a Fellow of the College of Surgeons of London ?—Yes. 

Have you been accustomed to the examination of substances by the 
microscope ?—Yes. 

Principally of vegetable substances for some years ?—I have for many 
years been in the practice of examining vegetable structure by the micro- 
scope. : 

Both in recent vegetables and in fossil substances ?—I have. 

Did you lately receive some specimens of different minerals, including 
some of the Torbanehill mineral ?—I did. 

From whom did you get the Torbanehill mineral ?—I got some specimens 
from Dr. Fyfe, and some others from the Aberdeen Gas Works, in the 
presence of Mr. Leslie, the manager. 

Did you subject these specimens of the Torbanehill mineral to micro- 
scopical examination ?—I did so. 

How many sections of it did you take >—Eighteen. 

From the same piece, or from different pieces ?—From eight different 
pieces. 

Did you or did you not find vegetable structure in these sections P—I 
found vegetable structure in every section. 

Have you examined different cannel coals with the same view ?—I 
have. 

What cannel coals ?—I have examined Lesmahagow cannel coal, 
Capeldrae cannel coal, Wigan cannel coal, Methil cannel coal, and 
Halbeath parrot coal; and also the Kinneil coal from Bo’ness. 

Tn what way would you speak of the examination of these minerals, 
and of the examination of the Torbanehill mineral, in reference to the 
vegetable structure ?—I am quite convinced, that in the sections of these 
different coals there are parts which cannot be distinguished from each 
other. 

Vegetable structure in all ?—In all. 

And in some parts this mineral undistinguishable from the others ?— 
Certainly. 

The Boghead mineral has considerable varieties of aspect in itself ?-—It 
ha 


S. 
Different shades of colour?—There are black, brown, and spotted 
pieces—black pieces with brown spots. 

In the lightish-colour portions of the Boghead mineral, what is that 
you saw ?—I saw vegetable cells in these portions. 

The structure that you saw is cellular structure ?—Yes. 

Besides the cells that you saw, what else did you notice P—I noticed 
also woody fibre, or woody tissue. 


Jrom the Coal Measures of Torbane-hill. 57 


Are there some yellow spots in this light-coloured portion of the 
mineral ?—There are. 

What do you think these yellow spots indicate ?—'They indicate the 
existence of vegetable cells. 

Have you applied any test to endeavour to find out whether they were 
vegetable or not ?—I have, Sir; I have many reasons for concluding that 
they are vegetable cells. 

Would you mention your reasons?—I find that they can be perfectly 
isolated—they project upon the edges of all sections of the mineral—they 
are rounded—they are as uniform in size as the cells of other vegetable 
structures—the general appearance of the section is that of a piece of 
vegetable cellular tissue—the yellow spots do not act upon polarised 
light, or act upon it very feebly. 

Generally speaking, do you consider that the Torbanehill mineral 
exhibits the same appearances of structure and position microscopically 
as the other cannel minerals ?—It does. 

Did you see Dr. Greville’s drawings ?—I not only saw the drawings, 
but I saw him make them. 

You had long previously examined the minerals ?—I had; long and 
carefully. 

Do these drawings appear to you to represent the general character of 
the mineral P—They do. 

And you believe these drawings to represent cellular tissue ?—I do. 

Your sections were taken at random from the general specimens that 
you had ?—Certainly. 

As fair specimens that you thought the mineral would exhibit ?—That 
was my chief object in obtaining them from the Aberdeen Gas Works. 
I took the specimens for as fair average specimens of the Torbanehill 
mineral as | could obtain. 

And they would have supplied similar representations as those Dr. 
Greville has given, in your opinion ?—I am satisfied of that. 

Cross-ecamined by the Dean of Faculty— You say Dr. Greville’s 
drawings represent the same thing that you saw ?—They do, 

Did you examine the ash of this coal >—Yes. 

With the microscope ?—Yes. I consider the examination of the ash as 
liable to great sources of fallacy, and place no dependence upon it. 

Your reasons?—I should not look upon the ash to make out the 
structure it contains. 

That is not your reason, but a repetition of your opinion. What is 
your reason ?—Because I would expect the greater portion of vegetable 
structure, if it existed, to be destroyed by the process of combustion. 

Did you ever examine the ash of ordinary coal with the microscope P— 
I have not. 


Dr. R. Ky GrevinLe.— Examined by Mr. NEAVEs. 


Dr. Greville, I believe gon have devoted a good deal of your attention 
to the study of botany ’—Yes, it has been the principal study of my 
whole life. 

And in connexion with that to the use of the microscope ?—I may say, 
without exaggeration, that for many years I have used the microscope 
almost every day. 

Among other branches of the vegetable kingdom, you have studied and 
written upon the cryptogamic family, which includes the ferns ?—Yes. 

And which requires particular use of the microscope in order to illustrate 
its fructification ?°—Yes. I may add that 1 have made the drawings of 
everything [ have published from my own microscopical investigations. 


J 


58 Structure of a peeuhar Combustible Mineral, 


1 made drawings of the outline and structure of two or three hundred 
ferns alone. 

Were you asked to assist some gentlemen using the microscope to 
represent the appearance of some sections of minerals ?—Yes. 

These are the drawings you made ?—Yes. 

Did you yourself look at various sections of the minerals besides those 
that you have represented ?—I did, especially with regard to the Boghead 
mineral. I examined under the microscope eighteen different slices made 
from eight different specimens of the substance. 

Were these Dr. Redfern’s specimens ?—Yes. 

Did you discover vegetable structure in these ?—Unquestionably, in 
the whole of them. 

Did you examine some other minerals—some cannel coals that this 
gentleman had?—I examined all those coals of which the names are 
appended to the drawings. ‘There is the Methil, Lesmahagow, and 
Capeldrae coals. 

Now these are correct representations, to the best of your ability, of 
what they present ?—They are; they might be more minutely finished, 
but they give, I hope, a fair representation of the structure. 

Did it appear to you, from your examination of these different things, 
that they were the general structure of the mass, or any incidental 
structure ?—I have no hesitation in saying that it was the general 
structure of every specimen, not incidental. I should consider it to be 
quite impossible it could be incidental. 

Do you consider that there is a material difference or a substantial 
identity between these different bodies, as represented in these different 
minerals ?—I do net. I examined the specimens of the three upper- 
most sketches, and the structure was so similar, that I considered them 
to be identical. here is a difference, but nothing amounting to any- 
thing essential in the structure. The Lesmahagow, Capeldrae, and 
Torbanehill are.essentially the same. I may be allowed to add, that in 
each slice there is a difference in every part of that slice, so that you 
must be guided by the general view. 

From your botanical ‘knowledge, have you any doubt that these repre- 
sentations exhibit vegetable cells : ?-T have no more doubt of that than of 
my own existence at this moment. 

Will you explain what that paper is?—[handing witness one of the 
drawings spoken to by Professor Balfour|—That drawing represents 
vegetable cells in an isolated state, scattered throughout the substance, and 
observable, I believe, in most coals—certainly in most coals that I have 
examined. It is difficult to say what they may be, but I have no doubt 
that they are vegetable cells, solitary cells. They may possibly be 
transverse segments of cells, but I would not venture to say anything 
more than that. I believe them to be vegetable cells. 

Found in this mineral ?—We have found these vegetable cells in the 
Boghead as well as in others. 

Will you explain what these two drawings represent ?—! handing witness 
two of the drawings spoken to by Professor Balfour |—The uppermost one 
represents cellular tissue in the Torbanehill mineral; and, upon the 
whole, I consider that as one of the most satisfactory specimens which I 
examined ; the cellular tissue is so unequivocally marked, and so regular, 
that it may be compared to that of a recent plant. It is exceedingly well 
defined. What I have represented in the drawing is not in the least 
exaggerated. No person accustomed to botanical sections would hesitate 
in believing that to be cellular tissue. The lower drawing represents a 
beautiful specimen, but whether that is general in the mineral I could not 


Srom the Coal Measures of Torbane-hill. a9 


say. It represents a modification of the vascular structure of platrts 
called technically the scalariform structure. I can compare it best by 
comparing it with an old basket. It is an unequivocal vegetable structure. 

What occurs in its neighbourhood in the rest of the section ?—'This 
was the whole that I saw. The other portion was not ground so thin, 
and I could not see what it consisted of ; but judging from tfig traces of 
these vessels at the extreme edges, I have no reason whatgver to doubt, 
that if the remainder of the section had been ground sufficiently thin, we 
would have seen the continuation of that structure. 

But the other cells that you described here are diffused through the 
entire mass of the substance ?—In all the specimens I examined it was 
uniform throughout the whole. It was exceedingly well marked in the 
one that represents the transverse section of the cells. 

You get the width of the cells more distinctly when you cut the 
transverse section ?—You get the area more distinctly shown. 

Cross-examined by the Dean of Faculty.—Can you explain to me what 
are infusoria ?—Infusoria represent minute animals invisible to the naked 
eye—visible only to the microscope. 

Where do you find them ?—It is very difficult to say where you do not 
find them. Generally they are sought for in fluids. 

You find them in minerals also?—I am not prepared to answer that 
question. Iam not sufficiently acquainted with the subject to venture 
to answer it. 

Then you cannot tell me what appearance they present when found in 
minerals when examined under the microscope ?—No, | am not aware of 
their occurring. 


Professor HARKNEss.— Examined by Mr. Youna. 


Professor Harkness, you are Professor of Geology in Queen’s College, 
Cork ?—Yes. 

You succeeded Dr. Nicol ?—About six months ago. 

You have devoted considerable attention to the study of geology ?—I 
have. 

And also to the examination of objects by the microscope ?—Yes, so far 
as relates to fossil plants. 

You have visited Torbanehill ?—I have. 

You went down one of the pits ?—I was down two of them. 

And examined the mineral as it lay in the earth ?—Yes. 

And made yourself acquainted with its geological composition ?—I 
found it to occur in the proper coal measures. 

Exactly in the position you would expect to find coal ?—Decidedly so. 

You found nothing whatever in its geological composition to lead you 
for a moment to doubt that it was coal?—Nothing; on the contrary, 
everything to induce me to believe that it was coal. 

Did you form any opinion upon the mineral itself?—I formed the 
opinion, that from the appearauce of the mineral it was a coal. 

Did you take some specimens of the mineral away ?—Yes, I did, for the 
purpose of making a more careful examination. 
And after that examination you retained your opinion ?—I did. 
And your opinion now is that it is a coal?—Decidedly so, without any 
manner of doubt. 

Did you make some sections of the mineral which you took away with 
the view of microscopic examination ?—So far as regarded fossil plants. 

Did you find the structure familiar ?—I found the structure peculiar, 
and the fossils characteristic of the coal formation. 

How many structures are there in coal and coal plant ?—There are two 


60 Structure of a peculiar Combustible Mineral, 


or three distinguishing characteristics, first the woody fibre, the scalariform 
tissue, and the cellular tissue. 

Is this upon the examination of a great many sections?—Yes. That 
was generally, not mere accidental structure of particular pieces. 

You saw a drawing made by Dr. Greville?—I was present when that 
drawing was made. 

And that gave a sufficiently distinct idea of the course of examination ? 
—Yes. 

Of the Torbanehill and some other coals P—Yes ; and the Lesmahagow, 
Kinneil, Capeldrae, and some other cannels. 

I believe the drawing’was made from a section furnished by you ?— 
That is a most beautiful specimen of cellular tissue. 

This is the most beautiful specimen you have seen of woody fibre P—I 
distinguish woody fibre from cellular on account of the more regular 
formation of the cells. 

You have no doubt that this is a vegetable product >—Not the least. 


{ Witness was shown the drawings illustrative of cellular tissue and 
woody fibre, and distinguished each with great precision. | 


You know what shales are ?—Yes. ; 

Do shales ever exhibit vegetable structure P—As shales they do not. 

How would you describe a shale ?—There are several forms of shales. 
Supposing the coal to be so mixed with earthy matter as to be incapable 
of being used for fuel, then that would be called a coaly shale. 

And when the coaly matter is so great in proportion to the earthy mat- 
ter that it will burn ?—I should consider this a coal. 

And more or less pure according to the admixture of earthy matter ?— 
All coals contain more or less of earthy matter, and accordingly the coals 
run into shales as the earthy matter increases. 

When you come to a substance beyond which a substance will not 
burn, you would call it a coaly shale ?—Yes. 

It is very difficult to draw the line at the exact ne ’—Very difficult. 

Has this mineral anything of the character of a shale ?—Not the least, 
so far as I have been able to detect. 

You have seen specimens of Methil coal, and examined them with the 
microscope ?—Yes. 

And did you find anything to distinguish the Boghead mineral ?— 
So far as external appearance went, I could scarcely distinguish the one 
from the other, and there was also a great similarity in internal structure. 

There are a variety of cannels which approach each other very closely ? 
—In regard to the distinction between the two there is not a more com- 
mon one than this, the capability of burning and being used for the 
purposes of fuel. 

If the substance would burn, and could be used as fuel, you would say 
it was a coal ?—Yes, I would. 

If any substance is sold in the market as a coal, is it a coal?—Yes, I 
should think so. 

There is no science against this >—None that I am aware of. 

Cross-examined by the Dean of Faculty.—I suppose whatever comes out 
of the coal measures and burns by itself is coal?—No; I would not say 
that. You might get a fragment of bitumen, which would not be coal, 
and that burns. by itself, 

Is that the only exception ?—I am not prepared to say that there are 
any other exceptions. 

Fracments of bitumen would be an exception ?—Yes. 

The | way by which you distinguish a coal from a shale, or a shale from 


from the Coal Measures of Torbane-hill. 61 


a coal, I understand is, that the one will burn, and that the other will 
not ?—The one will burn without the mixture of any extraneous matter. 

It will burn by itself ?—Yes. 

There are other distinctions ; but this is the distinction upon which you 
rested ?—Yes. 

You were going to tell us that there were a number of kinds of shales. 
Tell me some of these ?—There are some which are absolutely devoid of 
coaly matter—clay shales, which have no coal in them at all. 

Any other distinction ?—Yes; there are shales which I should charac- 
terize as bituminous shales. 

How do they differ from coaly shales >—They differ inasmuch as they 
give a bituminous smell when struck by the hammer; and they yield 
bitumen to chemical solvents. 

Do they burr ?—Yes, they burn in some cases. 

Where do you find most bituminous shales ?—Yon find them in Cam- 
bridge and in Dorsetshire, in the higher beds of the oolite. 

Do you find the Methil coal to be of a laminated and slaty structure >— 
I found some fragments that were laminated; but others present the 
conchoidal structure that you have in the Boghead, and is compost. 

The Boghead is compost ?—It is. 

Is the Methil coal so ?—It is generally so. 

But portions are slaty and laminated ?—Yes. 

Will you explain what infusoria are >—I have not given any opinion as 
concerning infusoria. 

But you can give one ?—They are minute microscopic animals. 

Where are they found ?—I generally find them in water. 

Are they not to be found in minerals?—I have not found them in 
minerals. 

But are they not to be found in minerals ?—They are found in certain 
mineral beds, but I have not found them in mineral beds. 


Dr. Wituiam AITKEN.—Hxamined by Mr. PENNEY. 


You made some sections of the Torbanehill mineral, and of some other 


coals ?>—Yes. 

Were they for your own examination, or some that Dr. Greville drew ? 
—TI did some, and also for my own. 

You got the returns from Torbanehill ?—I did. 

From the pit mouth ?—Yes. 

You made the sections fairly for the purpose of testing ?—Yes. 

Mr. Neaves then stated that they would not require to examine 
Mr. Glen, as his sections were also admitted. 


Having now read to you the evidence given by the micro- 
scopists on both sides of the question, I cannot refrain from 
making a few remarks on some of the statements of the 
defender’s witnesses. The subject to me is a painful one, for 
it is always with feelings of regret that I venture to differ in 
opinion from any scientific observer ; but, however contrary 
to my inclination, I have a public duty to perform, to say 
nothing of the character I have to sustain amongst you as 
a member of this society. I sincerely hope, however, that 
those gentlemen will take it all in good part, and believe that 
it is only for the reasons above assigned, and not from any 


62 Structure of a peculiar Combustible Mineral, 


public or private feeling of opposition to their opinions that I 
appear before you this night. 

I will not dwell long upon the subject, as it must be very 
clear to you all—first, that the specimens examined by these 
gentlemen must have had more or less of plant structure im- 
bedded in them; secondly, that they have evidently mistaken 
the peculiar arrangement of the combustible and earthy por- 
tions of the mineral for vegetable cellular tissue. Thirdly, 
they can certainly never have examined sections of many 
coals microscopically, as one and all tell you that they saw 
the same structure in the mineral as they did in coals. Had 
they made sections of coal in two directions, at right angles 
to each other, they could hardly have failed in seeing, almost 
at a glance, how much the sections differed in structure the 
one from the other. That such is really the case, even in the 
coals which they state in their evidence they have examined, 
may be shown by reference to Plate IV. In fig. 1 is repre- 
sented a transverse section of the so-called brown methil ; 
and in fig. 2, a longitudinal section of the same. The two 
structures are so different in appearance, that, had such 
sections been made, I feel confident there could not have 
been a second opinion on the subject. In fig. 38 is shown a 
transverse section of the black methil, and in fig. 4 a longi- 
tudinal section. ‘The differences, if anything, are even more 
striking than in the brown methil. But what will be said 
of figs. 5 and*6, which represent a transverse and longitudinal 
section of Lesmahagow cannel coal? That anything at all 
resembling such a structure as this, can be found in sections 
of the mineral in question, except when coal is present, I 
emphatically deny. 

Now, granting for a moment that the structure of the 
mineral be cellular, what plants, I would ask, could the cells 
have belonged to? Can any botanist produce a single 
instance of a recent or fossil plant of the same thickness as a 
seam of the Torbanehill mineral, which shall be made up of a 
mass of cellular tissue, that is, without vessels or woody fibres 
being present with the cells ? 

Again, if the structure be cellular, we should expect to find 
the most durable part of the cell—the cell wall—always pre- 
sent, which is not the case. If this view be correct, the yellow 
particles being solid must be the contents of cells, they cer- 
tainly cannot be cells. ‘The cell-wall also, as far as we know 
it, in recent and fossil plants, always presents on section a 
more or less uniform thickness and a homogeneous appear- 
ance; whereas the structure around the yellow particles in all 
cases, except where plants are present, is minutely granular, 


From the Coal Measures of Torbane-hill. 63 


being in reality the clayey or earthy ingredient of the 
mineral. 

None of the defender’s witnesses, it appears, ever examined 
the ash of coal; and one witness in particular, Dr. Redfern, 
stated that the examination of “ash in general was liable to 
great sources of fallacy, and placed no dependence upon it ;” 
whereas, it subsequently appeared that he had never examined 
the ash of ordinary coal with the microscope. 

Were I disposed to be hypercritical, I could mention many 
other points in the evidence that I entirely dissent from; but 
I trust I have already said enough, and will therefore sum up 
my remarks by stating that I consider the mineral in ques- 
tion is not a coal, being structurally different from all un- 
doubted coals, including those with which it appears it has 
been compared by the microscopists engaged by the defender. 
In order, therefore, that the scientific world in general may 
have an opportunity of judging for themselves whether this 
statement be correct or not, I have put specimens of the 
mineral and of these coals into the hands of the preparers of 
microscopic objects, and in a short time sections will be on 
sale by them and by the principal opticians in this metropolis. 

I might by some persons be accused of unfairness in 
making even these few remarks upon the evidence of the wit- 
nesses for the defence, when they are all located in different 
parts of Great Britain, and therefore not able to be present 
this evening to answer for themselves. I wish, however, 
that they could have been here, and more especially if they 
could have brought with them the sections upon which their 
opinions were formed, and the drawings which were produced 
in court. They might say, perhaps, that it would not be fair 
play to send their specimens, their drawings, and their remarks 
into an enemy’s camp; on my own part, however, I can ven- 
ture to state that | am ready to appear before any tribunal of 
scientific men in this kingdom, and my drawings and speci- 
mens shall be open to all who may be interested in the subject, 
to examine for themselves. I beg it may be expressly under- 
stood, that should there be any one point in this paper which 
on subsequent investigation may turn out to be incorrect, I 
shall be as ready to come forward and acknowledge myself in 
error as I now am to express an opinion not hastily formed : 
my only object, as I said before, is truth; and by truth I will 
abide. 

There is one other point that I would briefly allude to 
before drawing my remarks to a conclusion, and this is a 
portion of the Lerd President’s address to the Jury, in which, 


64 Structure of a peculiar Combustible Mineral, 


as before stated, Mr. Bowerbank and myself are placed in no 
very enviable position ; it is as follows :— 


“« Besides those gentlemen who were examined as geologists and che- 
mists, and who differ so widely, there was examined another class of men, 
and possessed of great attainments—I refer to the microscopists. One of 
them was the late President of the Microscopic Society of London—a 
learned body, who make it their object to pry into all things. Three of 
these gentlemen were examined for the pursuer, and four for the defender. 
The pursuer’s witnesses told you that there was no trace of organic struc- 
ture, no woody fibre or tissue, in short, no trace of vegetable matter in 
this substance, although occasionally there might be the incidental pre- 
sence of vegetable remains. ‘The witnesses of this class on the other side 
told you, on the contrary, that in every part of it there was the most clear 
vestiges of vegetable structure. I do not know, when I have so many 
geologists and so many microscopists telling me that it is not coal, and 
so many on the other side telling me the opposite, I say I do not know 
that I feel myself much the wiser, or further advanced in the inquiry. 
But if you have, in addition, a great number of chemists, and speaking 
with equal authority and equal contrariety, it is difficult to know what to 
make of the controversy. -I do not know that I have anything to say 
against the skill of the microscopists, or the skill of any of those gentle- 
men ; but one general remark may be made on the microscopic testimony, 
and it is, that there are those who see a thing, and also those who do not 
see it—those who do see it, cannot see it unless it is there, and those who 
cannot see it do not see it at all. But very skilful persons looking for a 
thing and not seeing it, creates a strong presumption that it is not there. 
But when other persons do find it, it goes far to displace the notion that it 
is not there. But there is another observation on the microscopic evidence 
that occurred to me. Ido not know whether I am under any misappre- 
hension, but I think that three, certainly two, of those examined by the 
defenders, are botanists also; and I do not think that any of those exa- 
mined for the pursuer, two of them from London, represented themselves 
as botanists. Now, the defender’s witnesses are accustomed to look for 
plants, and can understand them when they see them. The gentlemen on 
the other side again, looking for woody fibre or tissue, are not, as I under- 
stand, conversant or skilful in fossil plants. But finding such a difference 
of opinion, and such opposite conclusions arrived at by those persons, | do 
not know, unless you think that some gave their reasons more satisfac- 
torily than others—I say I do not know that I feel my mind much 
relieved from the difficulties of this case by listening to all that evidence. 
It is very interesting no doubt, and if they were all standing on one side, 
and nobody standing on the other side, it might be very satisfactory to 
one’s mind to listen to such evidence.” 


To such remarks I would briefly reply that, however 
severe a counsel may be in his cross-examination, and how- 
ever strong his language in addressing the jury may be, I 
think it to a certain extent excusable, as he is endeavouring 
to do the best for his client; but 1 must confess my great 
surprise that a learned judge should see fit to single out one 
set of scientific witnesses from the pursuer’s side, and hold 
them up, I would say, almost to ridicule; that he did so on 


from the Coal Measures of Torbane-hill. 65 


the present occasion, the part of the address which I have just 
read to you will show. I think it will eventually turn out that 
the two members of the Microscopical Society of London, 
“ that learned body who make it their object to pry into all 
things,” are accustomed to look for plants, and can under- 
stand them when they see them; nay, I will assert that they 
can do more, for they can tell when a particular structure is 
not a plant. Had his Lordship been silent on the point, he 
would not have laid himself open to these truly justifiable 
remarks, 

I would now, gentlemen, in conclusion, leave the matter in 
your hands. I think that the subject in question is one of 
the most important ever brought before the notice of this 
Society, and one which no set of men in this or any other 
country are so competent to investigate. Most of the members 
of this society are, as stated in the certificate for suspension, 
*‘ attached to scientific pursuits,” and most of them are in 
possession of the best instruments, and are accustomed to use 
them; let them, therefore, study the subject for themselves, 
and give independent testimony. Where, I might ask, can 
be found a correct definition of coal? I believe, at present, 
no such definition is extant, and it is on this account that I 
look upon the trial of Gillespie versus Russel, as one of the 
greatest importance to the geologist, the chemist, the mineralo- 
gist, and the microscopist; and | am of opinion that from it 
will spring, not only a perfect definition of coal, but of other 
combustible substances found in connexion with it, and, 
therefore, itis to be hoped that such contradictory statements 
as were made by the different scientific witnesses on the trial 
in question may in future be avoided. It remains, then, for 
the microscope, ‘‘ that most valuable of all scientific instru- 
ments (to quote the words of Mr. Ross) ever yet bestowed by 
art upon the investigator of nature,” to assist in deciding the 
true structure of coal, as it has already done that of many 
other organic substances of a previously-doubtful nature. 


“eorpis Jo Ayqeqoad 
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yep jo Ajoryuo sjstsuoo yse oy} ‘suring Aq 


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"IVOO "IVUUNIW 'TIUA-ANVEYOL Ras 


‘IVOQ) pue TVUANIPL TIIH-ANVAUOT, olf} Ud9MJoq AONAUNAATIGG JO SLNIOG 'IVdIONIYT 94} JO MALIA UVINAY T 


Roper, on the Diatomacee of the Thames. 67 


Some Observations on the Diatomace® of the Thames. By 
F.C. S. Roper, F.G.S. (Read January 25th, 1854.) 


In the year 1843 M. Ehrenberg, read before the Academy of 
Sciences of Berlin a paper on the microscopical marine infv- 
soria of the deposits of the Elbe,* in which he established the 
remarkable fact that at Gliickstadt, a distance of forty miles, 
and even above Hamburg, upwards of eighty miles, from the 
mouth of the river, marine siliceous-shelled Infusoria were 
found alive, and their skeletons deposited in such abundance 
in the mud of the river, that at the former locality they form 
one quarter to one-third of the entire mass, and that the pro- 
portion is still about half that amount at Hamburg, as far as 
the flood-tide extends. All his observations gave a great pre- 
dominance of marine over fresh-water species, even when the 
salt taste of the water was no longer perceptible. 

In the lists which accompany this paper, M. Ehrenberg 
enumerates thirty-four marine species, under the style of 
siliceous-shelled Polygastrica, the whole of which would now 
be classed as Alg@, under the order Diatomacee. The local 
distribution of these organisms is a point of some interest ; and 
as well-authenticated lists of species from the different localities 
in Great Britain have still been only partially attempted, I am 
induced to lay before the Society the results of some observa- 
tions on the deposits of the river Thames, which accord in a 
great degree with those made by Ehrenberg in the Elbe, 
though the proportion of marine to fresh-water species is more 
equal at corresponding distances from the sea. 

The abundance of the Diatomacee, and the facility with 
which the different species have been collected at Hull, 
Poole Harbour, and other well-known localities, where they 
may be eathered alive, and offer such advantages for acquiring 
an intimate acquaintance with their habits and modes of 
growth, has tended, in a great measure, to divert attention 
from those which are deposited by the Thames water ; and, 
with the exception of some species of Triceratium, Eupo- 
discus, and a few other forms, the greater part of the list I 
shall hereafter mention has been hitherto, so far as I am 
aware, altogether unnoticed, or at all events no special detail 
of them has been given from that locality. 

The chief cause, I imagine, for this neglect of the Diato- 
macee of the Thames and other rivers, has arisen from the 
fact, that observers have endeavoured to pursue the same plan 


* Verhandl. der Konigl. Preuss. Akad. der Wissenschaften zu Berlin, 
43. 


VOL, IT. h 


68 Roper, on the Diatomacee of the Thames. 


which meets with such success in the localities I have before 
alluded to, that is, to examine them in a living state ; but, as 
far as I can judge from my own experience, this affords a most 
unsatisfactory result ; and after a careful examination of the 
mud deposited at different points in the Thames, any one 
might easily arrive at the conclusion that the varieties to be 
met with were comparatively few, and, except for the exami- 
nation of some of the larger species, not worth the time neces- 
sary for extended observation. 

Having, some months back, brought home a bottleful of 
the black mud from the extremity of the Isle of Dogs, taken 
about half-way between high and low water mark, and for 
several nights successively submitted it to a careful examina- 
tion, the only species of Diatomacee | met with were a Trice- 
ratium favus, and several specimens of Coscinodiscus radiatus 
and Surirella splendida. 1 had laid it aside for some time, 
when it occurred to me that the same course of proceeding 
which is necessary to bring out the siliceous frustules from 
guano might prove equally efficacious with this Thames mud. 
Acting on this idea, | boiled a portion of it for some time in 
hydrochloric and afterwards in strong nitric acid, until the 
whole was perfectly clean: and, on mounting it, the result far 
exceeded my expectations; for though impossible to form 
an accurate conclusion, I should imagine that, excluding the 
coarse sand, nearly one-fourth of the finer part of the residuum 
was entirely*composed of the siliceous valves of different 
species of Diatomacee ; and the prevalence of marine forms 
also proves that, at the distance of nearly forty miles from 
the mouth of the Thames, their distribution is very similar 
to that previously described by M. Ehrenberg in the Elbe. 

The only observations on this point of the inquiry, as 
regards British rivers, that | have met with, are notices of the 
species which occur in the Humber, and in a paper by Mr. T. 
F. Bergin,* read before the Microscopical Society of Dublin 
in 1842, who, from a careful examination of the deposits of 
the Liffey, after a perusal of Ehrenberg’s paper on the Mud 
Banks in the Harbour of Wismar, was led to a different con- 
clusion; and stated it as his opinion that a few species of 
Navicula, not comprising 1-1000th part of the mass, were the 
only organized forms that occurred in the mud deposited by 
that river. The cause of this he attributes to the fact of the 
source of the river being so short a distance from the sea, and, 
having its rise in the mountains of Wicklow, the rapidity 


* Microscopic Journal, vol ii., p. 68. 


Roper, on the Diatomacee of the Thames. 69 


of the current is so great, that the germs of these minute 
organisms have not time to increase and multiply as they do 
in more sluggish streams, flowing for a long distance through 
alluvial deposits. 

A similar occurrence of marine Diatomacee at a considerable 
distance from the sea has, however, been noticed by Professor 
Bailey, in America, who, in his ‘ Microscopical Observations 
on South Carolina and Georgia,’ published by the Smithsonian 
Institution, expresses the surprise with which he found in 
Lake Monroe, 200 miles from the mouth of the St. John’s 
river, specimens of Amphiprora constricta, Odontella poly- 
morpha, and Navicula elongata, which he considered decidedly 
marine, and which had often occurred to him on the shores of 
the Atlantic. 

I now proceed to give lists of the species from different 
localities in the Thames, placing those from the Isle of Dogs 
first, and comparing them with the forms from Hammersmith 
and near Gravesend ; and though I have been unable at pre- 
sent to examine the deposits of the two latter localities so as 
to give more than a general view of the species, yet these are 
sufficiently well marked to show the distribution of those 
peculiar to marine and fresh water. 

In all the localities many species of Melosira, Odontidium, 
and other genera occur, which, from the want of good figures, 
I have been unable to name. The well-marked frustules o! 
those figured in the first volume of the Rey. William Smith’s 
valuable synopsis have been easily recognized, from the ex- 
tremely accurate figures there given. In all cases where any 
doubt existed, I have referred to slides of the species authen- 
ticated by Mr. Smith himself. In some few instances I am 
indebted to his kind assistance, and also to his able coadjutor, 
Mr. West, for the determination of forms I was unable 
satisfactorily to identify, and in a few others I have depended 
on the figures of Kiitzing’s work on the Diatomacee. One if 
not two species of Dictyocha occur in the mud from the Isle of 
Dogs, but I have excluded them from the list, as there appears 
some doubt if they can be correctly referred to the same order. 


Marine and Brackish Water Species from the Isle of Dogs. 


1. Epithemia sorex 9. Eupediscus argus 

2. F musculus | SO; - fulvus 

3. Amphora affinis 12. u radiatus 

4. SS hyalina 12. 2 sculptus 

5. Cocconeis scutellum 13. Actinocyclus undulatus 
6 if diaphana 14, fs sedenarius ? 
7. Coscinodiscus radiatus 15. Triceratium favus 

8 7 eccentricus 16, ee striolatum 


h 2 


Roper, on the Diatomacee of the Thames. 


39. Navicula Jennerii 

40. “ pusilla 

4l. 3 elegans 

42. Pinnularia directa 

43. “4 distans 

44, ts peregrina 
45. Stauroneis pulchella 
46. Pleurosigma hippocampus 
47. 53 strigilis 
48. Synedra gracilis 

49. »  crystallina 
50. i superba 

say) ES »  tabulata 

52. Doryphora amphiceros 
53. Boéckii 

54. Odontella aurita 


. Podosira Montagnei 

. Grammatophora marina 
. Zygoceros rhombus 

. Melosira nummuloides 
. Achnanthes (a spec.) 


Fresh-water Species, 


17. Triceratium undulatum 
18. alternans 
Ne), Cyclotella Kiitzingiana 
20. Campylodiscus cribrosus 
21. bi-costatus 
22. Surirella Brightwellii 
23. A ovata 
24, F gemma 
25. ae fastuosa 
26. salina 
Zhe” Ley; blionella marginata 
28. 9 punctata 
29. 7, acuminata 
30. KA gracilis 
31. Nitzschia sigma 
32, x angularis 
33. - parvula 
34 93 dubia 
35. Amphiprora alata 
36. Navicula elliptica 
37. A didyma 
38. 5 punctulata 
1. Epithemia turgida 
2. a alpestris 
3. argus 
4, Cymbella Ehrenbergii 
5. ae maculata 
6. sy cuspidata 
{6 ve helvetica 
8. Amphora ovalis 
9. Cocconeis placentula 
10. Campyllodiscus costatus 
11. Surirella biseriata 
12. . pinnata 
13. Cymatopleura solea 
14. a elliptica 
15. Nitzschia sigmoidea 
16 Pr linearis 
17.. Navicula ovalis 
18. 5 producta 
19. ., rhyncocephala 
20. i inflata 
21. 55 eibberula 
22. amphisboena 
23. Pinnularia acuta 


24, 

25. 
26. 
27. 
28. 
29. 
30. 
31, 
32. 
33. 
34, 
35. 
36. 
37: 
38. 
39. 
40, 
41. 
42° 
43. 
44, 
| 45. 


Pinnularia viridis 


ve oblonga 

5 major 

a radiosa 
Stauroneis linearis 

4 Pheenicenteron 

S anceps 
Pleurosigma attenuatum 


Synedra radians 
Cocconema lanceolatum 


5 parvum 
a cistula 

Gomphonema acuminatum 

“5 capitatum 

a curvaium 

is constrictum 

ay cristatum 

dichotomum 

Odontidium hyemale 


Fragillaria capucina 
Tabellaria ventricosa 
Diatoma vulgare 


From this list it appears that out of one hundred and four 


species, fifty-nine are peculiar to marine and brackish water, 


of which thirty are decidedly marine. 


The following six 


species are, however, all that are identical with those included 
in M. Ehrenberg’s lists from Gliicksiadt and Hamburg, viz. : 
Coscinodiscus radiatus and eccentricus, Triceratium favus, 
Surirella gemma, Eupodiscus argus, identical with T'ripodiscus 


Rorer, on the Diatomacee of the Thames. 71 


germanicus and Actinocyclus undulatus, probably identical with 
Actinoptychus senarius. This would seem to show that though 
the general results were similar, yet from some peculiarity, 
either in the water or the distribution of these minute 
organisms, the species abounding in the rivers of the north of 
Europe are marked with a distinctive character from those 
found in the Thames. The prevailing form in the Elbe ap- 
pears to be the Actinocyclus, and its allied genus Actinoptychus 
of Ehrenberg, of which he enumerates no less than fourteen 
species out of the thirty-four marine forms that he recognised. 

On comparing with the foregoing list from the Isle of Dogs, 
the species which occur in the mud at Hammersmith and near 
Gravesend, it appears, that though a few marine forms are 
still found at the former locality, yet the preponderance of 
fresh-water species is very great ; whilst at the latter the marine 
and brackish water species, with a few exceptions, alone 
occur. 

The following lists include all I have at present met with 
from those localities :— 


Marine and Brackish Water Species from the Thames near Gravesend. 


1, Epithemia musculus 21. Nitzschia angularis 

2. Cocconeis scutellum | 22. Amphiprora alata 

3. Coscinodiscus eccentricus 23. Navicula Jennerii 

4, i radiatus 24, = didyma 

5. 5 marginatus ? 25 “ punctulata 

6. Eupodiscus argus 26, Pinnularia cyprinus 

": ~ crassus 27. Stauroneis salina 

8. Actinocyclus undulatus 28. Pleurosigma angulatum 

9: ee sedenarius ? 29, - hippocampus 
10. Triceratium favus 30. ss Balticum 
iG ae alternans 31. Doryphora amphiceros 
12. Campylodiscus cribrosus 32. Achnanthes brevipes 
13. Surirella ovata 33. Grammatophora marina 
14, = gemma 34, Podosira Montagnei 
ine a fastuosa 35. Melosira nummuloides 
16. Tryblionella acuminata 36, Bs suleata 
Nits marginata 37. = salina 
18. - punctata 38. Odontella aurita 
19. Nitzschia sigma 39. Orthosira marina 


20. ,, dubia 


Fresh-water Species from Gravesend. 


1. Cocconeis placentula 5. Navicula minutula 
2. Coscinodiscus minor 6. Synedra ulna 

8. Nitzschia sigmoidea 7. Cocconema cistula 
4, Navicula cuspidata 8. Cyclotella rotula 


Marine and Brackish Water Species from the Thames near Hammersmith, 


1. Amphora membranacea 
2. Coscinodiscus eccentricus 
3. Actinocyclus undulatus 


4, 


Surirella Brightwellii 


5. Tryblionella gracilis 


6. 


acuminata 


72 Roper, on the Diatomacee of the Thames. 


7. Nitzschia sigma 11. Pleurosigma hippocampus 
8. Nitzschia parvula 12. Doryphora amphiceros 
9. Navicula elliptica 13. Gomphonema marinum 
10. Pinnularia directa 14. Odontella aurita 
Fresh-water Species from the same Place. 
1. Epithemia turgida 16. Pinnularia viridula 
2. Cymbella Ehrenbergii iG - stauroneiformis 
3. Amphora ovalis 18. Pleurosigma attenuatum 
4. Cocconeis placentula 19. Synedra ulna 
5. Campylodiscus costatus 20. Cocconema cymbiforme 
6. Surirella biseriata 21, He cistula 
7. Cymatopleura solea 22. Gomphonema acuminatum 
8. 5 elliptica 23. 4 constrictum 
9. “3 apiculata 24, Fragillaria virescens 
10, Nitzschia sigmoidea 25. Diatoma vulgare 
11. Navicula amphisboena 26. Melosira arenaria 
12. a crassinervia 27. 3 varians 
13. a inflata 28. Fragilaria capucina 
14, 93 euspidata 29. Coscinodiseus minor 
15. + amphirhynchus 


From these lists it appears that at Gravesend, out of forty- 
seven species, eight only are decidedly peculiar to fresh water ; 
whilst at Hammersmith we find there are twenty-nine fresh- 
water species out of a total of forty-three ; showing, however, 
that the influence of the flood-tide, even at that distance from 
the sea, gives a decided character to the Diatomacee deposited 
by the water. The following ten species are all that are 
common to the three localities :— Coscinodiscus eccentricus, 
Actinocyclus undulatus, Tryblionella acuminata, Nitzschia sigma, 
Pleurosigma hippocampus, Deryphora amphiceros, Odontella 
aurita, Cocconeis placentula, Nitzschia sigmoidea, and Cocconema 
cistula, of which the three latter alone are peculiar to fresh 
water. These are all forms which more extended observation 
on the deposits of other river and estuary deposits will pro- 
bably prove to be most universal in their distribution. I have 
found most of them in the mud of the Avon from Bristol, and 
also in that deposited at Pembroke Harbour; but it will re- 
quire a careful examination of many other deposits to prove 
that any have a purely local habitat, or are entirely confined 
to sea or fresh water. 

The following species which occur in the Thames have also 
been found by Professor Bailey in America, recorded in ‘Sil- 
liman’s Journal of Sciences’ for 1845, vol. xviii. p. 837 :— 


In the Mud from Charleston Harbour. 


Actinocyclus senarius _ Rhaphoneis amphiceros 
Coscinodiscus eccentricus | rhombus 
Eupodiseus argus Triceratium favus 
Pinnularia didyma | : Zygoceros rhombus 
Pleurosigma Baltieum 


Roper, on the Diatomacee of the Thames. 73 


And in the Mud from Newhaven Harbour. 


Actinocyclus senarius Pinnularia peregrina 
Coscinodiseus eccentricus y didyma 
Gallionella sulcata Rhaphoneis rhombus 
Grammatophora marina 


A proof of the widely-extended distribution of these species. 

From the first of the foregoing lists I have selected a few 
species for more particular notice, and annex drawings of the 
most interesting, on the scale adopted by Mr. Smith, namely, 
400 diameters. 

There is a large species of Cocconeis (PI. VI. fig. 1), elliptical 
in form, and marked longitudinally with undulating striz, and 
also with faint transverse lines, concentric with the extremities 
of the valve, but only visible with a high power and oblique 
light. ‘The perfectly elliptic form and peculiarity of the cross 
striae seem to distinguish it from the C. placentula of Mr. 
Smith ; but I am doubtful whether it may not be a variety of 
that species. 

Of the four species of Hupodiscus, the most plentiful is 
E. radiatus, which, from one specimen, in which three frustules 
were conjoined, may probably sometimes occur concatenated, 
in a similar way to. Odontella aurita. E. sculptus, the most 
peculiar in its markings, is rarely met with; and £. fulvus 
and argus are sparingly distributed. The latter shows the 
delicate hexagonal reticulations alluded to by Professor Quekett 
as marking the Tripodiscus Rogersit of Professor Bailey. The 
star-shaped cells appear, when seen by direct light, to be 
placed in the centre of small bosses or protuberances, in which 
it differs from all other Diatomacee that | am acquainted with, 

The Actinocyclus undulatus of Mr. Smith’s Synopsis occurs 
abundantly. This species appears to include the Act?- 
noptychus senarius of Ehrenberg and Kiitzing ; but after a 
careful examination of many specimens, [ have been unable 
to make out any undulations similar to those of fig. 4, in 
Piate V. of the Synopsis, in the large species that occur in the 
Thames and elsewhere; and although a multiplication of 
species is a point carefully to be avoided without good 
grounds, it appears to me that the appellation undulatus 
should be confined to a small form, in which these undula- 
tions distinctly occur, and the large and well-known species 
retain the name originally applied to it by M. Ehrenberg, 
namely, A. senarius. 

Sparingly distributed, I have another large and beautiful 
dise (fig. 2), with sixteen septa, the surface of which is covered 
with faint cross striae, similar to those of Plewrosigma ; and in 


* See Histological Catalogue, p. 212. 


74 Rorer, on the Diatomacee of the Thames. 


that respect it resembles the valves from Natal, for which 
Mr. Shadbolt proposed the name of Actinophenia ; but I find 
this striation is no distinctive character, as all the specimens 
of A. undulatus (or senarius) that I have examined have the 
same peculiarity, and the septa are plainly discernible, espe- 
cially with the parabolic condenser. In the lists I have ap- 
plied to it provisionally the name of Actinocyclus sedenarius, 
as it approaches very nearly to Ehrenberg’s figure of that 
species in the ‘Berlin Transactions’ for 1839, tab. 4, p. 2. 
The septa appear to have their origin from the smooth central 
portion or pseudo-nodule, and to terminate at slight eleva- 
tions or openings at the margin of the disc, and in perfect 
specimens those on one valve are opposite to the mterspaces 
on the other. The front view exhibits slight traces of undu- 
lations, as in fig. 18, not in continuous waved lines, but rising 
to points at the extremities of the rays, giving the side view 
an appearance similar to that of a ridge-and-furrow roof. ‘The 
diameter varies from 1-288th to 1-187th of an inch. 

Of the genus Triceratium four species occur. A small one, 
by no means uncommon, is represented by fig. 38, which 
I consider the J’ striolatum of Ehrenberg; it has convex 
sides, small horn-like processes at the angles, which are rather 
obtuse, and is marked with minute dots or cells, radiating 
from the centre. In the determination of this species I am, 
after a careful examination, compelled to differ from Mr. 
Brightwell, who, in his monograph of this genus in a late 
Number of the ‘ Microscopical Journal,’ refers to a Paper by 
M. Ehrenberg in the ‘ Berlin Transactions’ for 1839, in which 
there is a figure of T. striolatum, and the following description 
of the species: —“‘ Testulz lateribus triquetris convexis, angulis 
sub-acutis, superficie subtilissime punctato-lineata, dorsi cin- 
gulo medio levi;” and yet Mr. Brightwell describes it as 
with ‘concave ends,” and figures it with concave sides; and 
in the frustules I have seen of his species, the central band on 
the front view is punctate or cellular, whereas it is described 
by Ehrenberg as smooth. 'The cellular structure of the side 
view is also so plainly apparent, that it would hardly have 
been described as “ subtilissime punctato-lineata ” by so careful 
an observer. Looking, therefore, at Ehrenberg’s figure and 
description, I should conclude that the species figured by 
Mr. Brightwell cannot be the T. striolatwm, but should re- 
ceive some other appellation. The concave sides would seem 
to refer it to T. pileus of Ehrenberg; but I have not seen a 
figure or full description of that species. 

Triceratium alternans of Bailey is rarely met with ; and I 
have only one specimen of J. undulatum, in which the peculiar 


Roper, on the Diatomacee of the Thames. 75 


projection of the posterior valve beyond the undulating sides 
of the upper, as noticed by Mr. Brightwell in his Paper before 
alluded to, is plainly shown. 

Campylodiscus costatus and cribrosus are frequently met 
with. Another small species is represented by fig. 4, which 
Mr. Smith informs me he has named bi-costatus, and that he 
will give a figure of it in the addenda to his second volume. 
In appearance it so much resembles C. clypeus, that I had 
applied that name to it, especially as that species is included 
in Ehrenberg’s lists as occurring at Gliickstadt, Hamburg, and 
some localities in Holland, and was found by Professor Bailey 
in Lake Monroe. The valve is nearly circular, saddle-shaped, 
canaliculi about forty, distinct, length at the sides about half 
the radius, at the ends much shorter. The central portion 
has two narrow bands of coste parallel with the terminations 
of the side canaliculi, Diameter is about 1-384th of an 
inch, 

The most abundant species in all the slides I have examined 
is represented by figs. 7 to 10, which I believe would all 
be included as varieties of Doryphora amphiceros by Mr. 
Smith, and as different species of Rhaphoneis by Ehrenberg 
and Kiitzing. The difference of form is so great, and the 
peculiarity of the cellular markings so apparent, that they 
appear to furnish data for specific distinction quite as gued 
as are afforded in many species of Wavicula and Plewrosigma. 
Not having Ehrenberg’s figures or descriptions to refer to, 
I am guided solely by the “species Algarum” of Professor 
Kiitzing. Fig. 7, from its lanceolate form, strong granular 
markings, and well-marked median line, might probably be 
referred to Rhaphoneis gemmifera. The length varies from 
1-319th to 1-320th of an inch; breadth, about 1-1090th of an 
inch: it occurs but sparingly. Fig. 8 is rarely met with, but 
is readily distinguished by its more robust form, the greater 
delicacy of its striz, and the slightly marked and nearly 
parallel sides of its median line. The length is 1-349th of 
an inch, and breadth 1-779th of an inch. It would be referred 
to Rhaphoneis fasciolata. Fig. 9 is exceedingly common, and 
in the size of its markings resembles fig. 7, but differs in 
being more concentric, and nearly obliterating the median 
line at the acute extremities of the valve. The breadth of 
the valve is also much greater in proportion to the length. 
The length is 1-600th of an inch, and breadth 1-1224th of 
an inch. It agrees with Rhaphoneis pretiosa. Fig. 10 is 
widely different from any of the preceding, and is by no 
means abundant. The valves are very diaphanous, the mark- 
ings faint, median line obscure, and form sub-orbicular, the 


76 Rover, on the Diatomacee of the Thames. 


apices being very short; the length is 1-588th to 1-779th of 
an inch, and breadth 1-1034th to 1-968th of an inch. I 
should refer it to Rhaphoneis rhombus. The only point of 
distinction between this genus and the Doryphora of Pro- 
fessor Kiitzing appears to be the presence of a stipes; and it 
would be a point of some interest to determine whether 
these forms are attached in a similar manner, or whether, as 
I imagine from the abundance with which they occur, and the 
absence of any direct negative observations, the frustules are 
free as in Navicula. 

A large and well-marked species is represented by fig. 5, 
which has not, I believe, been hitherto figured as British. I 
have been unable to obtain a front view of a perfect frustule, 
though the single valves are by no means uncommon, By a 
comparison with some specimens of Zygoceros rhombus from 
Petersburg, Virginia, kindly lent me by Professor Quekett, 
I have little doubt that it can safely be referred to that 
species,* as the only difference is, that in the Thames spe- 
cimens, the side view of the valves is rather broader in 
proportion to the length. The valves are nearly rhomboidal, 
slightly produced at the extremities, and terminate in a pro- 
jecting tubular horn or spine. The surface is minutely 
punctate with small hexagonal cells, radiating from the 
centre, and has from three to six small spinous processes at 
the sides, with two rather longer at the extremities of the 
valve. The length varies from 1-300th to 1-183rd of an inch, 
and breadth from 1-575th to 1-260th of an inch, : 

Figs. 11 and 12 are, I believe, front and side views of 
Zygoceros surirella of Ehrenberg. I have only met with one 
specimen of the perfect frustules, represented by fig. 14, which 
agrees in form with the figure given by him in the ‘ Berlin 
Transactions’ for 1839, tab. 4, fig. 12, and shows the smooth 
central band and striations, which distinguish the side view. 
Fig. 16, which I consider the side view of a larger specimen, 
somewhat resembles the genus Rhaphoneis, but differs, in 
the markings being nearly parallel, and though granular, so 
confluent as almost to appear as lines; the central smooth 
portion terminates in two lobes, corresponding with the pro- 
jections, which appear at the extremities when the front view 
is obtained, ‘The length is 1-714th to 1-1240th of an inch, 
and breadth 1-1500th to 1-2500th of an inch. I have met 
with the same species in the deposits of Pembroke Harbour. 

Fig. 6 a and d represents a small cross-shaped valve that 
occurs sparingly, which Mr. Smith, from a drawing, thought 


* The genus Zygoceros is included by Mr. Smith in that of Biddulphia ; 
this will, therefore, be the Biddulphia rhombus of the ‘ Synopsis.’ 


Roper, on the Diatomacee of the Thames. 77 


might be referred to his Odontidium tabellaria: it is peculiar, 
from the strongly-marked cross striz, which occur on each side 
of the valve; the length is 1-1385th and the breadth 1-1750th 
of an inch. The form of the valve is similar to Ehrenberg’s 
figure of Staurosira construens,* which he describes ‘as a 
four-angled Fragilaria, separated from the nearly allied genus 
of Amphitetras, by the absence of openings at the four angles,+ 
but without authentic specimens for comparison, it is im- 
possible, from the small outline figure he gives, to refer it 
with certainty to this genus. Mr. West informs me he has 
met with it from many other localities} From the Thames 
near Gravesend I have lately obtained a large and fine spe- 
eimen of Coscinodiseus, about the 1-107th of an inch in 
diameter. It has a smooth spot in the centre of the valve, and 
with that exception is covered with hexagonal cells, radiating 
towards the circumference. Mr. Smith informs me it is quite 
new to him, but approaches somewhat to C. marginatus, but 
differs from the descriptions given of that species. I have at 
present no other forms, either from this locality or at Hammer- 
smith, that call for special notice. 

From the foregoing observations it appears that at the 
distance of at least fifty miles from the sea, the deposits of 
the Thames are still, to a certain extent, influenced by marine 
forms of life, and that at Greenwich, which is about forty 
miles from the mouth of the river, a most distinct marine 
character is shown by the examination of the species of 
Diatomacee which occur there. I think it very probable 
that many species are only brought up by the flood-tide, and 
being unable to exist in the slightly-brackish water, the 
siliceous skeletons are merely deposited in those parts of the 
river least subject to disturbing causes, and that they would 
rarely be met with in a living state. That they have a per- 
ceptible influence on the formation of shoals and mud-banks 
in the bed of the river there can be no doubt; and the great 
abundance and general distribution of species serve to illus- 
trate the occurrence of similar deposits in a fossil state, at 
localities now far removed, by alterations in the earth’s surface, 
from the streams or harbours in which they were originally 
deposited. 

Another point, probably worthy of attention, is the in- 
fluence these organisms have in the formation of deltas at the 

* See Berlin Academy Transactions, 1847, tab. 1, fig. 44. 

+ See Berlin Academy Proceedings, 1843, p. 45. 

~ From specimens I have lately seen of Odontidium Harrisonii, W. S., 
I am inclined to believe that this may be a small form of that species 
rather than 0. tabellaria. As it is a doubtful form I have not included it 
in the lists. 


78 Roper, on the Diatomacee of the Thames. 


mouths of large and slowly-flowing rivers, such, for instance, 
as the Mississippi, in which the mean velocity of the current 
at New Orleans is only about one mile and a half per hour 
for the whole body of water. Sir Charles Lyell, from expe- 
riments on the proportion of sediment carried down by the 
river, has calculated that, taking the area of the delta at 13,600 
square miles, and the quantity of solid matter brought down 
annually at 3,702,758,400 cubic feet, it must have taken 67,000 
years for the formation of the whole.* Now, as the siliceous 
frustules ot the Diatomacee are secreted from the water alone, 
and would most probably be extremely abundant in so 
sluggish a stream (especially as Professor Bailey has found 
both marine and fresh-water species abundant in the rice- 
grounds), there can be little doubt that, without taking the 
larger proportion noticed by Ehrenberg in the Elbe, even if it 
were considerably less, it would reduce the above period by 
several thousand years, and the same cause would probably 
apply with equal force to the Ganges and Nile. M. Ehren- 
berg considered that at Pillau there are annually deposited 
from the water from 7,200 to 14,000 cubic metres of fine 
microscopic organisms, which in the course of a century 
would give a deposit of from 720,000 to 1,400,000 cubic 
metres of infusory rock or Tripoli stone. 

My principal object in the foregoing paper has been to 
direct the attention of microscopists more particularly to the 
Diatomacee* deposited by rivers and in tidal harbours, not only 
in those localities where they occur in overwhelming abun- 
dance, on the surface of quiet estuary waters, but in the mud 
itself, in which many of the rarer forms, and doubtless many 
new species, are yet to be found, That such an examination 
is still a desideratum is, I think, shown by the fact that out of 
the 279 species described by Mr. Smith in the first volume of 
his ‘Synopsis,’ only six are given as inhabitants of the 
Thames, and a very limited number to the Avon, Orwell, and 
some other rivers; whilst the Severn, the Mersey, and many 
of our tidal harbours are altogether unnoticed. 

That examinations of this nature may sometimes prove 
useful in an economical point of view is very probable, parti- 
cularly as it has been noticed that the best samples of guano 
contain the greatest number of these siliceous skeletons, which 
doubtless serve to replace the large amount of silica ab- 
stracted from the soil by the cereal crops. Hence it is pro- 
bable that the deposits of many of our rivers would have a 
beneficial effect if applied to the land, and it rests with the 
microscopist to point out the most favourable localities for 


* Lyell’s Principles of Geology, 8th edit., p. 219. 


Roper, on the Diatomacee of the Thames. 79 


obtaining it. Ehrenberg notices an instance where this has 
been done in Jeverland, where a blue sand, abounding in cal- 
careous and siliceous shells, is collected, and greatly increases 
the fertility of the arable soil to which it is applied; and 
Professor Bailey also states that the mud of Newhaven har- 
bour is used as a fertilizer, and is found to contain 58°63 
per cent. of silica. 

The distribution of the lower forms of Algae, particularly 
the Diatomacee, is probably more extended, both in point of 
time and geographical range, than any other class of or- 
ganized beings. Thus we see associated with gigantic reptiles 
and other extinct forms, several existing species of Diatomacee 
occurring in the chalk formation before the deposition of the 
tertiary strata, proving that the Eocene group is not strictly 
entitled to that designation, but that the dawn of the world in 
which we live extends much further back in the history of our 
planet.* And with respect to their local distribution, Dr. 
Hooker, in alluding to the deposits of the Victoria Bar- 
rier in the Atlantic Ocean, remarks,+ “‘ There is probably no 
latitude between Spitzbergen and Victoria Land where some 
of the species of other countries do not exist. Iceland, Britain, 
the Mediterranean Sea, North and South America, all possess 
antarctic Diatomacee. The siliceous coats of species only 
known living in the waters of the South Polar Ocean have 
during past ages contributed to the formation of rocks, and 
thus they outlive several successive generations of organized 
beings. The Phonolite stones of the Rhine, and the Tripoli 
stone, contain species identical with what are now contri- 
buting to form a sedimentary deposit (and perhaps at a future 
period, of rock), extending in one continuous stratuia for 400 
miles.” 

With the distribution of these forms in our own country 
we are only at present partially acquainted, and the prepara- 
tion, therefore, of carefully-compiled lists of species from 
different localities is still a point to be desired, and might 
probably lead to some interesting generalizations. 

In conclusion, I have only to hope that this slight attempt 
to bring before the Society the results of a careful examination 
of the Thames deposits may induce other and more expe- 
rienced observers to take up the same subject in other locali- 
ties. The facts | have brought forward are sufficient to 
afford, in the words of an excellent observer and late member 
of this Society, ‘‘a striking proof of the important part which 


* Humboldt’s Cosmos, p. 265. 
{ Dr. Hooker, Flora Antarctica, vol. ii., p. 505. 
t Mr. Edwin J. Quekett, in London Physiol. Journ. Feb, 1844, p. 145. 


80 Roper, on the Diatomacee of the Thames. 


these minute organisms were created to perform in the depo- 
sition of materials for the earth’s surface, and stamp upon 
reflecting minds that no creature, even the most minute, is 
formed without special purposes ; and that the least in size of 
all, by the organization given to them by the great Architect 
of the Universe, have been employed to carry out his un- 
fathomable intentions.” 


Ree? ORT 


OF 


THE FOURTEENTH ANNUAL MEETING 


OF THE 


MICROSCOPICAL SOCIETY. 


Tue Microscopical Society of London held their Fourteenth 
Annual Meeting, February 15th, 1854,—Grorce Jackson, 
Esq , President, in the Chair. The Assistant Secretary read 
the following Reports :— 


Report of Council.—According to annual custom, the Council 
have to make a Report on the state and progress of the Society 
during the past year. 

The number of members at the last anniversary was—ordi- 
nary members 198, associates and honorary 5, giving a total 
of 203. Since that time there have been elected 28, making 
the total number 231. This number must, however, be re- 
duced by 3, who have retired, making a final total of 228, 
and being an increase of 25 upon the number at the last 
anniversary. 

The cabinet of objects and the library have been increased 
by various donations ; and there are also in the possession of 
the Society various drawings and diagrams relating chiefly to 
papers read at the meetings of the Society, together with 
copies of the several parts of the Transactions and of the 
Journal, 

The Council have also to state that, in consequence of the 
great inconvenience of the present rooms, they have decided 
upon removing from them. The Society will return to the 
rooms of the Horticultural Society in Regent-street, if possible, 
by the meeting on the 29th March. 

VOL. Il. i 


Fourteenth Report of 


84 


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‘SUOLIGAV GHL FO LWOday 


the Microscopical Society. 85 


The President delivered the following Address :— 


GENTLEMEN,—I have much pleasure in again congratu- 
lating you on the state of our finances; for, although the 
balance in hand is only twelve pounds more than that of last 
year, yet we have been enabled to pursue our usual course of 
investing the compositions received from life-members, and 
have thus increased our funded property from 210/. 5s. 11d. 
to 2591. 4s. ld. It is the opinion of some who have had ex- 
perience in these matters, that a society which judiciously 
expends its yearly income is in a more healthy condition than 
one which hoards a large portion of it, and that therefore we 
ought carefully to avoid becoming rich. Until, however, our 
dividends form a much larger proportion of our annual assets 
than they do at present, we need entertain no fears on this 
head ; while the possession of a reserve fund to fall back upon 
in case of need cannot be regarded as an evil. 

By the arrangement which has been made with the editors 
for the supply of the ‘ Microscopical Journal’ gratuitously to 
all our members, and by the prompt publication of our trans- 
actions, which have been brought down to the end of the year, 
a steady increase both of members and papers may be reason- 
ably expected ; of which [ trust the experience of the past 
year is but the commencement. Twenty-eight new members 
have been elected, and twelve papers, many of them of con- 
siderable interest, have been read. 

That of Professor Wheatstone, on the application of bino- 
cular vision to the microscope, has pointed out the advantages 
we may expect to derive from this principle, when certain 
optical difficulties have been overcome; and Mr. Wenham, 
by his ingenious contrivances and admirable workmanship, 
has vanquished some of these difficulties, and given us a 
glimpse of the benefits in store for us. 

The modification of artificial light by the intervention of 
coloured glasses has often been attempted, but it has generally 
been found to impair definition. The combination proposed 
by Mr. Rainey, for the purpose of stopping the heating rays, 
although it sensibly diminishes the light, appears to answer 
remarkably well. 

Dr. W. Gregory, Mr. Shadbolt, and Mr. Roper have con- 
tributed papers on Diatomacez. The latter, on those of the 
Thames, is particularly interesting, as opening a field of 
research in our own vicinity, the specimens being obtained 
from localities with which we are all acquainted. 

Mr. Legg’s paper on sponge-sand contains many hints 


86 _ Fourteenth Report of 


which collectors and mounters of objects will find useful in 
their pursuits. Mr. Boswell has communicated an interesting 
fact on the mode of progression of Actinophrys Sol. His 
subsequent paper on the bird’s-head processes in Polyzoa had 
been anticipated by the accurate and more extended observa- 
tions of Mr. Busk, read two months before. The valuable 
paper of Professor Quekett, on “ a combustible mineral from 
the coal measures of Torbane Hill,’ clearly demonstrates the 
presence, not merely of the remains of plants, but of a peculiar 
woody structure in every description of coal, and the absence 
of this peculiar structure in the mineral in question. 

In microscopic botany we have been favoured with two 
interesting communications: one by Dr. Hobson, on the 
development of tubular structure ; and the other on the disease 
affecting the vine, by Mr. T. West. 

As most of these papers have been already published, a 
more extended analysis of them would only be tedious. I 
would rather occupy a few minutes in considering how far this 
Society, during the fourteen years of its existence, has accom- 
plished the objects which its founders had in view at its 
formation. 

On turning back to our “ History, Constitution, and Laws,” 
we find it recorded that one of these objects was the ‘* promo- 
tion of improvements in the optical and mechanical construc- 
tion of the microscope.” With the improvements which 
have been made in the construction of object-glasses, the 
Society for many years had but little to do; although, by 
promoting the use of the instrument, and by keeping alive a 
spirit of rivalry between the different makers, it was not 
altogether without influence. Recently, however, an amateur 
among our own members has demonstrated the possibility of 
getting good definition with an angular aperture that admits 
of no appreciable increase ; and has thrown out suggestions, 
which, if carried into effect, will be productive of still further 
advantages. 

In the mechanical construction of the instrument, and in 
the different methods of illumination, so many improvements 
have been made by our members, that I should take up too 
much of your time were I to attempt to enumerate them. 

The next object proposed for the Society, “ the communi- 
cation and discussion of observations and discoveries,” has 
constituted the principal occupation of our hours of meeting; 
and for the interest and variety of the subjects, I need only 
refer to the volumes of our ‘Transactions.’ 

These observations have been altogether the result of imdi- 
vidual and self-directed researches; but it is worthy of con- 


the Microscopical Society. 87 


sideration whether more might not have been done had we 
adopted the co-operative and systematic mode of proceeding 
recommended by our first President. That Professor Owen’s 
suggestions may not altogether be lost sight of, I will, with 
your permission, quote a paragraph or two from his Address at 
our Second Anniversary ! 

After remarking on the importance of conceiving clearly 
the aim of our researches, and giving a right direction to our 
exertions, he says: “ A slight glance even at the classes of 
natural objects, of which the intimate structure remains but 
partially, if at all, known, will suffice to show us how many 
are the subjects that might be profitably selected by an indi- 
vidual or a committee for a systematic series of microscopical . 
observations. In the animal kingdom, for example, how little 
we know of the modifications of the microscopical structure of 
shells recent and fossil, of the stony habitations of the nume- 
rous class of polypes, of the crustaceous coverings of the 
annulose animals, of the calcareous coverings of the Echino- 
dermata, or of the bones in different classes of animals, and in 
different parts of the skeleton of the same animal ! 

“In Mineralogy how much remains to be done in the 
microscopical investigation of different classes of rocks, as of 
oblites, of sands, flints, &e. 

“If committees were appointed to take different subjects 
of minute research under their respective care, in how short 
a time might a vast body of microscopical facts be accu- 
mulated !” 

Selecting a few subjects from the Professor’s list, let us see 
what the systematic researches of three individuals, quite dis- 
tinctly carried on, have effected. The structure of shells has 
been ably investigated both by Dr. Carpenter and by Mr. 
Bowerbank ; the structrue of flints and agates also by the 
latter ; and that of bones, developing general views of much 
importance, by our indefatigable Secretary. 

Had committees been appointed, as Professor Owen sug- 
gested, and had their members worked with half the zeal and 
assiduity displayed by these three gentlemen, what a vast 
body of microscopical facts might by this time have been 
accumulated ! 

The “ formation of an arranged collection of microscopical 
objects” was another of the ends proposed to be effected by 
the Society ; but, considering the number of our Members, 
and that many of them are dextrous manipulators, frequently 
engaged in mounting specimens, the progress made in 
stocking our cabinet is by no means a subject of congratula- 
tion. The last object proposed to be attained was “ the esta- 


88 _ Fourteenth Report of 


blishment of a library of standard microscopical books.” 
Here also, although something has been done, we have no 
cause for boasting. But if every Member who wishes to 
refer to such works, and cannot find what he wants in our 
library, were to address a note to the Council, giving the title 
of the book needed, we should gradually have these deficien- 
cies supplied. 

There are one or two subjects of microscopical investigation 
that do not appear to have attracted our attention so much as 
might be wished. 

Some communications from the Rev. J. B. Reade, in the 
early days of the Society, served to show that the microscope 
might be made of great utility in delicate chemical re- 
searches; and a paper by Dr. Bird Herapath, in the Fifth 
Number of the ‘ Microscopical Journal,’ strongly confirms 
this view ; but, with the exception of some incidental notices 
of the application of chemical tests to determine the nature 
of organic structure, very little of chemical microscopy has 
come before this Society. For this there may be a sufficient 
reason; the subject is a special one, and chemists may 
prefer bringing their microscopical observations before the 
Chemical Society, to the alternative of submitting chemical 
matters to the Microscopical. How far they are right I will 
not determine. 

When we look over the list of our Members, and observe 
the number of medical men included in it, we may well be 
surprised that our ‘ Transactions’ have been enriched with so 
few papers on Animal Pathology. Had this been the case 
only since the institution of the Pathological Society, a reason 
similar to that above assigned might account for it; but even 
now it may fairly be questioned whether the accuracy of dis- 
coveries in microscopical pathology would not be better 
tested by a body of men accustomed to use the instrument, 
and to examine matters of all kinds with it, than by ose 
who have not had these advantages, however well they may 
be acquainted with the general subject. 

A physician in a neighbouring country some years ago 
announced that, by the aid of the microscope, he had disco- 
vered a pathognomonic symptom of pulmonary consumption 
in a peculiar egg-shaped body occurring in the sputa. It 
was afterwards found that in the hospital to which he was 
attached the consumptive patients breakfasted on arrow-root, 
and the peculiar bodies were some of the unbroken starch 
granules that had stuck to their mouths. 

In both the addresses of Professor Bell this want of papers 
on Animal Pathology is noticed; and his ideas are so just, and 


the Microscopical Society. 89 


his language so clear and forcible, that 1 cannot better con- 
clude the subject than by quoting the last paragraph from 
his Address at our Sixth Anniversary: ‘Let us remember,” 
said he, “ that the instrument which we employ is capable of 
elucidating subjects of far more importance than the distinc- 
tion of species of animalcules, and the demonstration of the 
structure of a zoophyte. The relief of suffering, and the sal- 
vation of life itself, are amongst the legitimate objects of 
microscopic research. Let not our medical members, then, 
be satisfied with the mere amusement, or even the bare scien- 
tific information to be derived from it; but let them employ 
it as an important means of carrying out the great objects of 
their profession, in determining the nature of diseased struc- 
tures, the distinctions between the healthy and morbid states 
of the tissues, and, consequently, in enlarging our means of 
restoring health to the sick, ease to the suffering, and life to 
the dying.” 

It only remains, Gentlemen, for me to express the satisfac- 
tion which I feel in resigning this Chair to one whose inti- 
mate knowledge of physiology in both its branches, no less 
than his general scientific attainments, so eminently qualify 
him to preside at our meetings. 

It was unanimously resolyed—That the Reports of the 
Council and Auditors be received ; and that the Reports, with 
the President's Address, be printed. 

The election of officers took place ; when the following were 
declared elected :— 


Officers. 
PEPER a ws Dr. CarrENTER. 
Geaistirer ee. Oe Sar N. B. Warp, Esq. 
aE. Us) a JoHn QUEKETT, Esq. 


New Members of Council. 


Dr. Lionet Brace. 

Joso. Gratton, Esq. 

M. MarsuHatt, Esq. 

Samu. C, WuiTsreaAD, Esq. 


In the place of 


Warren De La Rug, Esq. 
W. Gittert, Esq. 

Joun Ler, Esq., LL.D. 
Rosert Wartine'ron, Esq 


ae 

Hoae, on the Water-Snail. 91 
; 4 . 4 Py 

as a 8 2 : e*- of x 


Observations on the ered and Gafwmsityy the WaTER- 
SNalL (Limneus stagnalis). By Japez Hoae, M. REC. S., &e. 
(Read March 29th, 1854.) E 


* 


In submitting the observations which I have the honour of 
bringing to the notice of the Fellows of .the Microscopical 
Society this evening—on the Development and Growth of 
the Water-snail (Limneus stagnalis)—1 do so with considerable 
diffidence. When I first gave the subject my special atten- 
tion, and began to jot down the remarks that occurred to 
me as growing out of my experiences, I was not fully aware 
of the extent to which many able investigators had traversed 
the same ground before me. So far back as 1754, precisely 
a century since, Baker, in his book entitled, ‘ Employment 
for the Microscope’ (p. 325), was the earliest to describe 
**a small water-snail and its spawn, or eggs, fastened in little 
masses, against the sides of the glass,” in which he kept 
them. It also engaged the attention of the illustrious 
Swammerdam; and, more recently, that of Reaumur and 
Dr. Grant. Mr. Bowerbank’s very interesting and careful 
observations on the ‘ Structure of the Shells of Mollusca and 
Conchifera,’ and the scientific researches of Dr. Carpenter, 
have thrown great additional light upon this subject. A brief 
record of my own personal investigations, with regard to this 
department of microscopic observation can, therefore, present 
no signal feature of interest beyond that of confirming and 
enforcing the experience of the talented and eminent micro- 
scopists who have preceded me. It is with this view that I 
venture to lay before the Microscopical Society the few 
remarks which I have now the privilege of reading, happy if 
I shall have contributed, in however slight a degree, to add in 
any way to the store of knowledge already accumulated. 

Into a glass vase, where my stock of Chara, Vallisneria, &c., 
is growing, I introduced last Autumn a single Limneus, for 
the purpose of observing its habits; I was then more espe- 
cially curious to see its mode of creeping along, under the 
surface of the water, by means of its fleshy foot. Upon one 
occasion, as [I sat watching the movements of the animal, 
attached as it then was to the side of the vase, near the surface 
of the water, it suddenly became uneasy, moving to and fro, 
and ina short time it began to deposit very slowly, through 
a fissure near its ventral aperture, a small gelatinous sac, 
filled with transparent specks, at the same time firmly gluing 
it to the glass. This sac I examined with a pocket magnify- 
ing-glass, and found it contained fifty-six ova. Each egg was 

VOL. IT. : 


92 Hoae, on the Water-Snail. 


of an ovoid form, and consisted of a pellucid membrane filled 
with a transparent fluid, having a very minute yellow spot, the 
yolk, adhering to one ade of the cell-wall. Seen with the 
sunlight falline upon it, it had all the brilliant colours of the 
soap- -bubble. Viewing it again on the second day, I observed 
that the yolk had a eral spot, or nucleolus, rather deeper 
coloured than the rest. On the fourth day the yolk had 
changed its position, and doubled in size, as shown shghtly 
magnified (Plate VII. fig. 1). Upon a closer examination, a 
central depression, or transverse fissure, could be seen, which, 
on the sixth day, plainly indicated the line of demarcation in 
the little mass, as represented at fig. 2. From this time it 
commenced to move round the whole interior of the cell, with 
a very slow rotatory motion ; the motion was increased when 
the sunlight shone upon it, from which I concluded, that, as 
it received more heat, its movements were thereby accelerated. 
The increase in size of- the two parts of the animal appeared to 
be uniform up to the sixteenth day, when the shell apparently 
occupied the larger portion, represented at fig. 3; and the 
spiral axis, foadd which the calcareous lamelles were being 
deposited, had a much darker colour than the soft, or cephalic 
extremity. On the eighteenth day the tentacle was visible, 
with a small black speck at its root, the eye; this was seen 
to be protruded with the movement ‘ot the tentacle. Upon 
closely watching it, a fringe of cilia could be seen surrounding 
the tentacle Snide al aperture ; and, from observing the direc- 
tion of the currents, I am led ie believe that the earliest 
rotatory motion is in a great degree, if not wholly, dependent 
upon the action of the pile A constant current being kept 
up in the cell-contents, we may conclude, that with this 
motion, we have the conversion of the cell-contents into the 
several tissues ; and probably the whorl-shape of the shell is 
likewise due to the same formative process. The rotation 
was, on every occasion of my observing it, from the right to 
the left, and this always combined with a motion around the 
eee 5 fhe embryo performing a circuit, as represented magnified 
at fig. 4, and forcibly reminding me of M. Wichura’s scientific 
investigations into the curious property possessed by the 
ieaeeviot plants, of winding generally in a particular direction. 
He observes :— 

“Tt is a very remarkable phenomenon, that the cirenlarly or heliacally 
acting forces of nature follow an unchanging, definite, lateral direction in 
their course. In cosmical nature the planets “describe heliacal lines, wind- 
ing to the right in space, by virtue of their circulation from west to east ; 
since this is combined with the advance, in company with the sun, towards 


a point in the northern hemisphere. In the department of physics we 
meet with allied phenomena in the circular polarization of light, and in 


Hoae, on the Water-Snail. 93 


the course of electro-magnetic spirals. Organic life exhibits the same 
laws in the circulation of the blood, in all cases starting from the left side 
of the animal body ; and in the heliacal windings of the shells of Mollusks, 
which follow a direction determinate for every species. But plants, above 
all, give evidence of a wonderful obedience to such laws, in the direction 
of the spiral vessels, the heliacally winding trunks of trees, winding stems 
and leaves, and probably also in the circulation of their saps.” * 


Professor Quekett has directed attention to this subject, 
especially with regard to plants, in his ‘ Histological Lec- 
tures.’ To proceed :— 

From the twenty-sixth to the twenty-eighth day the little 
animal was actively engaged in making its way out of the 
ege, in the advanced stage represented “at fig. 5, leaving its 
shell behind it in the ova-sac, and immediately attaching itself 
to the side of the glass. The ciliary motion is then better 
seen; each tentacle being surrounded at the extreme edge by 
a row of cilia kept in motion by bands of muscular fibre : the 
cilia are protruded from beneath the shell, and kept'incessantly 
at work, in conjunction with those surrounding the opening to 
the taouth : ; thus bringing a constant current AG water for the 
zration of the Penehce situated above the oral aperture ; 
and at the same time a due supply of nourishment for the 
growth of the little animal. And it is a remarkable fact, that, 
as soon as the gastric teeth are properly matured to enable 
it to cut the vegetable substances growing in the water, the 
cilia being no longer required, then disappear, and drop off, 
from the tentacles. The tentacles and oral fringe of cilia are 
represented magnified, in the drawing, at fig. 6. But if, on 
the other hand, the young animal be kept in fresh water 
alone, without vegetable matter of any kind, it still retains its 
cilia, and attains only to a small size ; it then acquires gastric 
teeth, but of a very imperfect character, which never attains 
to perfection in form or in size. If at the same time it is 
confined to a small narrow cell, it will only grow to such a 
size as will enable it to move about freely; thus adapting 
itself to the necessities of its existence. 

Dr. Grant, I believe, first pointed out the ciliary motion in 
the embryo of some salt-water species of Gasteropoda. In 
examining the embryos of Buccinum undatum and Purpura 
lapillus, which are also enclosed in groups within transparent 
sacs, he was struck with an incessant motion of the fluid in 
the sac towards the fore-part of the embryo; and he then 
noticed that this motion was produced by cilia placed around 
two funnel-shaped projections on the fore-part of the young 


* M. Wichura, ‘“‘On the Winding of Leaves,” translated by Arthur 
Henfrey, F.R.S., ‘ Scientific Memoirs,’ 1853. 
k 2 


94 Hoge, on the Water-Snail. 


animal, which form the borders of a cavity, in which he per- 
ceived a constant revolution of floating particles. He also 
observed these circles of cilia in the young of the species of 
Trochus, Nerita, &c., in which the embryo was seen revolving ~ 
round its axis. He met with the same appearance in the naked 
Gasteropoda, as the Doris, Eolis, &c. ‘The embryo of these 
revolve round its centre, and swims rapidly forward by means 
of its cilia, when, it escapes from the ovum, Dr. Grant 
assigns various uses to these motions, but does not connect 
them with respiration or nourishment, although there can be 
little doubt that they are so. 

In some six weeks, or two months, the flattened form of 
the shell becomes gradually changed into that of the conical 
form of the full-grown animal (fig. 7).* 

That this little creature is hermaphrodite, like the common 
snail, is proved by my having only this solitary animal in my 
vase; and yet nearly- all the eggs deposited by it arrived at 
maturity. Like the common snail it is also copulative, as I 
have seen two animals mutually pass a thin tongue-like organ 
into a fissure between the body and upper surface of the pos- 
terior portion of the foot. 

I observed in the few eggs that did not come to maturity 
that the yolk only slightly increased in size, and then remained 
in that state until all the others were hatched, when the ova- 
sac became, the prey of other animals. 

This one snail deposited two and three of these ova-sacs 
in the course of the week ; and in two months I calculated 
that upwards of 800 young would result therefrom; thus 
it will be seen, that the number of eggs deposited by each 
individual is very great; fully explaining the rapidity with 
which this class of animals increases, either on land or in 
the water. 

The shell, as we have before seen, is begun at a very early 
stage in the formative process. It is first observed to have 
the shape of minute ovoid cells, which are deposited side by 
side around the axis, or central cell ; and this may be 
described as a cytoblast, enclosing a certain quantity of colour- 
ing matter, just sufficient to give it a distinctive appearance, 
from the previously-formed basement membrane. ‘The sides 
of one cell being in close contact with those of other cells, a 
gradual compression, or elongation, takes place, and we have, 
finally, resulting divisional ribs, hardened by the deposition 
of calcareous matter into a shelly covering. Subsequently all 
trace of the earliest cells and cytoblasts are lost. 


* In warm weather the eggs arrive at maturity in a much shorter time, 
especially when exposed to the light and warmth of the sun. 


Hoae, on the Water-Snail. 95 


My own observations upon the Limneus, in many important 
particulars, coincide with those of Mr. Bowerbank, made in 
1843, and published in the Transactions of this Society, upon 
the Structure of Shells of Mollusca, &c. Mr. Bowerbank thus 
explains the development of the shells of these animals :— 


“‘ Let us suppose the rudiment of the future shell to have been the 
result of the excretion of some mucus or lymph (properly, albumen) ; it 
would then be nothing more than a very thin transparent membrane, with 
a determinate figure dependent upon the figure of its species. In this 
membrane organizing cytoblasts and cells are produced and multiplied in 
rapid succession, until, by their increase and opposition, a cellular struc- 
ture is formed init. On their first appearance the cells are transparent 
and globular, but pushed on by the law of growth, which regulates their 
development, they very soon begin to secrete, from their inner surfaces, 
carbonate of lime. ‘The cells being filled with it, a solid structure is the 
result of their close aggregation ; the pattern being modified only by the 
form and degree of condensation of the calcigerous cells, in which it has 
been secreted. ¥: : bi = * 
A layer or stratum of shell being thus formed, another is produced from 
its inner surface by the same means, and then others, until the normal 
set is completed: the whole being kept together as one by the living 
tissues.” 


Mr. Bowerbank believes that the truth of this mode of 
formation is proved, not only by the structures he has dis- 
covered, but also by the phenomena which occur in its repa- 
ration of injuries ; for he says :— 

“This reparation is not made by a coat of calcareous matter, spread 
over the wound by the collar or mantle of the animal, as has been main- 
tained, but by an effusion of coagulable lymph, in which cytoblasts are 
produced in the first instance, and quickly succeeded by a cellular struc- 
ture, in which the earthy basis of the shell is secreted, and by which the 
scar is filled up, or the fracture cemented together.”’ 


This I have repeatedly verified, and always found that after 
an injury to the shell of either an embryonic, or more perfectly- 
formed animal, in a few hours subsequently the process of 
repair has been commenced by a deposition of cells, less in 
size, and somewhat more iuregular in form than the first. 
Upon breaking off an eighth of an inch from the edge of the 
shell of a full-grown animal, I observed that it first threw out 
a series of exudations of plasma, or albuminous matter; which, 
after some days, became hardened by a calcareous deposit, 
corresponding in appearance to the lines of growth of the old 
shell, but only to the extent required to convert the edge into 
a smooth and strong margin of about one-half the breadth 
broken off; and, ultimately, new lines of growth were 
thrown out beyond the edge of the mantle; this I clearly 
ascertained by scraping it with a fine knife, In reference to 
this part of my inquiry I may be pardoned for directing 


96 ‘Hoge, on the Water-Snail. 


attention to the very interesting observations of Professor 
Paget :— 


“That the reparative power in each perfect species, whether it be 
higher or lower in the scale, is in an inverse proportion to the amount of 
change through which it has passed in its development from the embryonic 
to the perfect state. And the deduction to be drawn is, that the powers 
for development from the embryo are identical with those exercised for 
the restoration from injuries : in other words, that the powers are the same 
by which perfection is first achieved, and by which, when lost, it is 
recovered. Indeed, it would almost seem as if the species that have least 
means of escape or defence from mutilation were those on which the most 
ample power of repair has been bestowed ; an admirable instance, if it be 
only true, of the beneficence that has provided for the welfare of even the 
least of the living world, with as much care as if they were the sole 
objects of the Divine regard.” 


Dr. Carpenter differs in some particulars from Mr. Bower- 
bank, more especially with reference to the vascularity of 
the shell, which, I believe, he entirely denies, and somewhat 
inclines to the more generally received opinion of Reaumur ; 
who, after careful examinations of the shells of Gasteropoda, 
came to the following conclusions :— 


“‘ That these calcareous defences are mere excretions from the surface 
of the body, absolutely extra-vital and extra-vascular, their growth being 
carried on by the addition of calcareous particles deposited in consecutive 
layers. The dermis, or vascular portion of the integument, is the secreting 
organ, which furnishes the earthy matter, pouring it out apparently from 
any part of the surface of the body, although the thicker portion, distin- 
guished by the appellation of the mantle, is more especially adapted to its 
production. The calcareous matter is never deposited in the areole of the 
dermis itself, but exudes from the surface, suspended in the mucus which 
is copiously poured out from the muciparous pores, and gradually hardened 
by exposure ; this calciferous fluid forms a layer of shell, coating the inner 
surface of the pre-existent layers to increase the size of the original shell, 
or else in furnishing at particular points for the reparation of injuries 
which accident may have occasioned.” * 


Now, if it be a mere excretion from the surface of a mem- 
brane, and neither vital nor vascular, how does Reaumur 
account for the deposit of the calcigerous cells, and subse- 
quent formation into shell, so early seen in the embryo; and 
that long before these cells can become consolidated by 
exposure to air? Mr. Bowerbank has seen, as well as myself, 
that at a very early stage of embryonic life, calcareous matter 
is deposited, and hardened into shell ; and this can be readily 
proved, by simply breaking up the egg, and submitting a 
portion of the contents to the action of a drop of very dilute 
acetic acid, when the carbonate of lime will be very quickly 


* « Article Gasteropoda.’ By Professor Rymer Jones. ‘ Cyclopedia of 
Anatomy and Physiology.’ 


Hoee, on the Water-Snail. 97 


dissolved out, with a brisk effervescence ; the basement mem- 
brane only remaining, as in the older shell. 

If the young animal be viewed under a power of 150 
diameters, the whole mass is sufficiently transparent, to show 
that the shell is an important part of the whole structure, and 
not “ suspended in mucus ;” but has a hardened and definite 
form long before it issues from the egg, or comes in contact 
with the external air, to produce any hardening effect upon it. 

Mr. Bowerbank has observed, that in the fully-formed shell 
“the mode of effecting repairs in the periostracum, affords 
evidence of a high degree of vitality.” As to the term eztra- 
vital, | know not what it means; and, I believe, no one who 
has bestowed care and attention in the investigation of the 
works of the Great Creator, will for one moment assume the 
smallest speck to be an eztra-vital production, or addition, 
Indeed, it appears to me that it would be as reasonable to 
deny the vitality of bone, or the growth of the lower organized 
cartilage, as to deny it to the shell of the pectinibranchial and 
pulmonated Mollusks. 

Dr. Carpenter says :— 


“It may now, however, be stated as an ascertained fact, that shell 
always possesses a more or less distinct organic structure ; this being, in 
some instances, of the character of that of the epidermis of higher animals, 
but in others having more resemblance to that of the dermis, or true 


skin.” 


From repeated examinations, I believe, with Mr. Bower- 


bank :— 


«¢ That the structure of shell is analogous to bone in some respects, and 
is formed much in the same manner as in particular kinds of bony matter, 
by the deposition of carbonate of lime within the cells of the membranes, 
which enter into the composition of the shell, or by the aggregation and 
coalescence of the calcigerous cells when the membrane is very sparingly 
produced ; and that it is made up of three strata. Each stratum being 
formed of innumerable plates, composed of elongated cellular structure ; 
each plate consisting of a single series of cells parallel to each other. 
These plates of cellular structure are deposited alternately in contrary 
directions, so that each series of cells intersects the one beneath it, at 
nearly right angles,” 

If to a portion of the periostracum a small quantity of very 
dilute acetic acid be added, to dissolve out the calcareous 
matter, and it be then viewed under a magnifying power of 
250 diameters, it will be seen to be composed of oval cyto- 
blasts, exhibiting distinct nuclei, beneath which will be found 
a fine membrane studded with minute spots, apparently the 
escaped contents of the cells. This membrane has a regular 
series of corrugations or folds arranged throughout its whole 
extent, which gives to the shell in certain positions an 


98 -Hoae, on the Water-Snail. 


iridescent lustre. Immediately beneath this is placed the 
transparent basement membrane of an even texture and very 
light amber colour, this is the albummous or animal mem- 
brane ; which with the layer before referred to, and above this, 
appears to me to be traversed by tubes, that no doubt run 
from the inner to the outer portion of the shell substance, and 
probably this net-work of pores have assigned to them similar 
duties to those in the human skin, viz., that of throwing off 
effete particles of matter, &c. 

The very small proportion of animal matter contained in 
this shell is a marked characteristic ; after the removal of the 
calcareous matter by dilute acid, we have the small residuum 
of a grain or two only ; from this cause the shell is very brittle 
at all times. The shell of the fully-formed animal is ovate, 
whorls five or six, elongated and dextral; thus favouring, as 
before observed, the notion that the circular motion of the 
embryo when in the egg determines the whorl.* 

The mantle of the animal partakes of the same character 
and structure as that of mucous membrane generally, more 
especially that portion of it lining the internal surface of the 
shell; thence it is reflected over the body, and forms a direct 
communication with the external shell and internal soft parts. 
Its other important use, besides that of depositing carbonate 
of lime, is the secretion of plasma, or a glazing fluid, which 
it spreads over the internal portions of the shell, and with 
which it lubricates the whole of the external parts, thus pre- 
venting any irritation that might arise from a drying up of 
the coarser particles of calcareous matter. Another use I 
have particularly noticed, is that of converting a large part of 
it, beneath the greater whorl of the shell, into an air-bag, or 
receptacle for holding a bladder of air, which must have consi- 
derable influence in rendering the shell buoyant and light, as 
by suddenly discharging it, the animal instantly sinks to the 
bottom. The animal is often seen to rise to the surface of 
the water for the purpose of taking in a supply of fresh air, 
which it does by opening a small valvular aperture, situated 
about the eighth of an inch above the ventral outlet. If the 
animal be removed from the water it immediately squeezes 
out this supply of air, at the same time it presses out the 
water from the body, for the purpose of enabling it to recede 

* For further information and much interesting matter upon this sub- 
ject I must refer to Mr. Bowerbank’s researches upon the ‘ Structure of 
Molluscous and Conchiferous Animals,’ most accurately and carefully 
illustrated, published in the Transactious of this Society, 1843. Also Dr. 
Carpenter’s researches, published in the Reports of the British Association, 
1544 and 1947; and his ‘ Principles of General and Comparative Phy- 
siology.’ 


Hoee, on the Water- Snail. 99 


into the interior of its shelly house for protection ; in this act 
it is greatly facilitated by the action of retractor muscles, 
having a strong tendinous attachment to the columella of the 
shell. The shell of the young animal, and thin portions of the 
older shell, viewed by polarized light on the selenite stage, 
are interesting and beautiful objects. In the young animal 
the growth of the membranous part is effected by the gradual 
expansion of the vascular and cellular tissues, and we are 
soon enabled to define the expanded foot. This is a fleshy 
disc, broader anteriorly and divided into transverse segments ; 
by a particular arrangement of the longitudinal muscular 
fibres it is enabled to perform a series of undulatory move- 
ments, by which means the animal glides smoothly along; its 
under surface is likewise studded over with a number of small 
orifices, which assist in causing a vacuum to be formed, and 
thus it suspends itself in an inverted position from the surface 
of the water, moving about in any direction, The muscular 
fibres, by their interlacements, greatly assist the animal in its 
progression, and in the performance of rapid movements ; at 
the outer edge it is turned over, or returned upon itself, 
forming a smooth and strong margin of condensed tissue and 
muscular fibres, which take their course in broad fasciculi, and 
gradually taper off toa thin tendinous attachment on the pillar 
of the shell. 

The mouth is situated at the under and fore-part of the 
head ; it is a muscular cavity, enclosing a dental apparatus, 
semicircular in shape and provided with transverse rows of 
projecting spines, or teeth of a horny structure, or, more 
correctly, alternating rows of incisor and canine teeth, each 
being pointed with silica, and accurately fitted to cut against 
each other; they are thus admirably adapted for the scraping 
or stripping off the cuticle from the blades of Vallisneria, 
which the animal does without killing the plant, and leaves it 
more accurately divided, than at all possible to obtain by the 
usual mode of splitting for microscopic observation, The 
gastric teeth are immediately joined to the oesophagus or 
gullet, and to this succeeds the gizzard, a strong muscular 
apparatus, a quarter of an inch in length, and having a rugose 
appearance, with transverse and longitudinal fibres, by means 
of which every movement requisite for the conversion of the 
food is effected, and passes into a small membranous sac, the 
stomach ; this is folded into longitudinal plice, and from it 
arises the large intestine of considerable length, having much 
of the appearance of intestine in the higher order of animals, 
excepting in colour ; a narrow longitudinal band passes down on 
either side of the external coat, and internally it is apparently 


100 Hoge, on the Water-Snait. 


supplied with valves. In its course it takes a considerable 
turn around the inner whorls of the shell, terminating in a 
rectum which has its vent placed between a small portion 
of the mantle and the under edge of the last whorl of the shell. 

The liver is not nearly so large as it is in the land-snail ; it 
consists of two lobes, and is enclosed in a strong capsular 
covering ; it pours a pale-coloured bile into the stomach by 
more than one duct, and is provided with a proper hepatic 
system of vessels. 

The heart is a strong muscular apparatus, having both an 
auricular and ventricular cavity ; it is surrounded by a very 
delicate membrane (the pericardium). In shape it is pyriform, 
with muscular cords stretching from side to side, of a highly 
elastic character, looking not unlike very fine bands of India- 
rubber alternately contracting and expanding ; these cords are, 
no doubt, analogous to the corde tendinee of the mammal 
heart. The heart receives the erated blood from the respira- 
tory organs, and propels it through the vessels at the rate of 
sixty times a minute. It is placed far back in the superior 
portion of the shell, near to the axis, where it is securely fixed 
without reference to the movements of the mouth or body of 
the animal. 

Like others of this family of aquatic Gasteropoda, the 
breathing apparatus resembles the branchiz of fishes in struc- 
ture; they are pectinated, and placed in three or four rows 
near the roof of a cavity under the integuments of the head, 
or rather above the oral opening, which is peculiarly arranged 
with retractor and other muscles, for the purpose of permitting 
an uninterrupted eration of the bloed as it is brought to the 
branchiz. 

The nervous system consists of many gangliz, or nervous 
centres, in place of a distinct brain, but “each of these 
gangliz may be considered as a distinct brain of the hetero- 
gangliate form.’ They are freely distributed throughout the 
body, but connected with each other by cords of communica- 
tion ; the nervous mass appears to be granular, and is some- 
what yellow in colour, whilst the nerves themselves are white 
and smooth, and invested with a delicate membrane (neuri- 
lemma). Professor Jones observes that— 


‘¢ One remarkable circumstance may be mentioned as peculiar to this 
class ; the changes of position of the nervous centres obey the movements 
of the mouth, with which they are intimately connected ; they are, in 
fact, pulled backwards and forwards by the muscles serving for the pro- 
trusion and retraction of the oral apparatus, and are thus constantly 
changing their relations with the surrounding parts. 

“The ganglia, placed above the cesophagus, sends off branches to supply 
the muscles of the head, the tentacles, and give origin to the optic nerves ; 


Hoee, on the Water-Snail. 101 


and from the sub-cesophagial ganglion, which fully equal the former in 
size, arise those nerves which supply the muscles of the body, and of the 
viscera.” * 

The singular adaptation of the eye must not be omitted ; 
this appears in the early embryonic stage to be situated within 
or on the tentacle, it is constantly retracted with it, which is 
due to the length of the pedicle, and to the retractile sheath 
of the optic nerve, enabling the animal to shorten it; at the 
same time the tentacle folds down over it, forming a protec- 
tive cover at all times. The eyes are situated at the base of 
the inner side of the tentacle, and resemble two very small 
black spots. When examined with a power of 100 diameters, 
they are seen to be transparent spherical lenses, surrounded 
by a black zone or iris, the pigmental layer is continued some 
distance down the pedicle. It is pear-shaped, and evidently 
the little animal is very quick-sighted, as he avoids every 
obstacle placed in his way, or quickly withdraws himself into 
his house if one attempts to touch him ; although in avoiding 
obstacles he appears to make great use of his tentacles as true 
feelers. The tentacles are composed of a dense elastic tissue, 
surrounded by a band of muscular fibre ; in shape they are 
triangular, with the base attached to the body of the animal. 

The Limnei are stated by Professor Forbes to have been 
found in the fossil state as far back as the Oolitic epoch; and 
the most ancient forms bear a striking resemblance to the 
common existing types. In England, at the present time, they 
are abundant in nearly all the waters where vegetable matter 
is growing, and in the slow running rivers, especially where 
the water-cress is found. 

The Limneus, like every other living thing, is infested with 
its parasite. Reaumur observed a sort of mite infesting the 
snail (Helix aspersa), they were securely lodged in the pul- 
monary cavity. Miiller also noticed in certain Gasteropods a 
worm; and Dr. Gould, examining a specimen of the Physa 
heterostropha, “‘ found the neck of the animal beset with 
numerous little things, looking like short, minute, white lines, 
attached like leeches, and which derive their nourishment 
from the fluids of the animal without his having the power to 
dislodge them.” 

M. bier states that he discovered a Filaria in the abdomen 
of Limneus stagnalis; and in many of the same family of 
Mollusca he has met with a worm allied to the Naides, 
“living in the respiratory cavity, or hanging like little tufts 
of threads from the sides of the abdomen; whence he named 
it Chelogaster.” Besides these, he says, “ a kind of Cercaria 


* Professor Rymer Jones, op. cit. 


102 -Hoae, on the Water-Snail. 


finds an appropriate nidus for their evolutions in the body of 
the lacustrine snails; and the curious transmutations of form 
they undergo in the interior of the animals, and the circum- 
fluent water, afford one of the most striking illustrations of 
Steenstrup’s theory of alternating generations.” * 

Upon observing the Limneus in my glass rather closely, I 
noticed that tts body was covered with the “ little white line- 
looking leeches,” described by Dr. Gould and M. Baer; upon 
carefully detaching one or two, and viewing them with a half- 
inch object-glass, it had the formidable appearance represented 
in the drawing at fig.8. It has an anterior mouth, surrounded 
with minute teeth or spines, over which it possesses great 
power. Suddenly it may be seen to dart out its body, at the 
same time projecting its mouth to some distance apparently for 
the purpose of seizing its prey, when it as quickly retracts 
itself within the shell of the animal, where it securely attaches 
itself to its body by a. posterior sucker. It is possessed of a 
great number of hooklets or feet, by these it creeps from one 
part of the body to another, but is always found adhering to 
those parts affording security in times of danger. Eventually 
they become so numerous that the animal’s life falls a sacrifice 
to its troublesome tormentors, having apparently no power to 
rid itself of them. 

In conclusion, [ would offer a word or two on the cell; the 
primordial wall of which does not enter into the formative 
process of the embryo. The cell contents only are required 
for the purpose of affording nourishment to the vital blastema 
of the nucleus, in which a cycle of progressive development 
once set up, goes on until the animal is sufficiently matured to 
break through the cell-wall,and escape from the ova-sac. At the 
same time it may be inferred, that this is in some way assisted 
by the process of endosmose, and in this way certain gases 
or fluids become drawn into the cell-interior, and thus mate- 
rially aid in the supply of nourishment for the growth of the 
animal. 

The cell-wall bears the same relation to the future perfect 
animal that the egg-shell of the chick does to it; it is but an 
external covering to a certain amount of gaseous and fluid 
matter, and for the purpose of placing the germ of life in a 
more favourable state for development, assisted as it is by 
an increase of temperature usually the result of a chemical 
action set up, or once begun, in an organism and a medium. 
The ovum, destined to become a new creature, originates from 
a cell enclosing a gemmule, from which its tissues are formed, 
and nutriment is assimilated,.and which eventually enables 


* Aoassiz and Gould’s ‘ Principles of Zoology.’ 


Hoae, on the Water-Snail. 103 


the animal successively to renew its organs through a series 
of metamorphoses, which give it permanent conditions not 
only different but even directly contrary to those which it had 
primitively. 

In this one fact are we not furnished with a well marked or 
broad line of demarcation between that of animal and vege- 
table life? In the development of the animal, the cell-wall 
takes no part in the formative process ; it is but an enveloping 
membrane required for a time, and then thrown off. On the 
contrary, in vegetable life it enters largely into the formative 
process, and ultimate development of all its tissues; it is ever 
to be found growing with its growth, cell-wall upon cell-wall 
intact, with or without its earliest contents. 


Note.—June 6th, 1854. 

My attempt to arrest the development of some young 
animals is still continued with perfect success. They have 
remained in the same narrow glass-cell, at the stage of growth 
before referred to, viz., about the size the animal usually 
attains during the first two or three weeks of its existence. 
They are now siz months old, alive and well, the cilia are re- 
tained around the tentacles in constant activity ; whilst other 
animals of the same brood and age, placed in a situation 
favourable to growth, have attained their full size, and have 
now produced young, which are of the size of their elder 
relations. 


DESCRIPTION OF PLATE VII. 


Fig. 
1.—A magnified representation of the increase and change of situation 
occurring to the yolk of egg of Limneus on the fourth day. 


2.—The change observed on the sixth day, showing the transverse fissure 
or divisional line in the mass. 


3.—The formation of the shell proceeding more rapidly, it appears on the 
sixteenth day as the larger portion of the embryonic mass. 


4,—The embryo performing its heliacal windings around the shell. 


5.—The embryo, or young animal, seen soon after it has issued from the 
shell. 


6.—The tentacles, with cilia, seen under a 3-inch object-glass ; the arrows 
indicating the course of the current produced by the cilia. 


7.—The natural size and form of the shell of a full-grown Limneus. 


8.—Parasitic animal found on the body of Limmneus, magnified 100 
diameters. 


104 Greeory, on Fossil Diatomacee. 


Observations on some Deposits of Fossil Diatomacez. By 
Wittram Gregory, M.D., F.R.S.E. 


tead April LUt : 
Read April 19th, 1854 


In the series of microscopic objects issued by the Zurich 
Microscopical Association, there occurs a specimen of Berg- 
mehl, stated to be from Lillhaggsjon in Lapland, which is 
very remarkable in several particulars. 

First, there is a very great abundance of LHunotia Triodon, 
exhibiting the most astonishing variations of outline, so that 
the extreme varieties in opposite directions, those, for ex- 
ample, which are short, compressed, and have strongly-marked 
prominences, and such as are long, flattened, the apices being 
lengthened out, while the prominences actually disappear, or 
can only be traced by a hardly-perceptible waviness in the 
dorsal outline, would hardly be supposed to belong to the 
same species, and yet a perfect and gentle gradation may be 
traced from the one extreme to the other. This remarkable 
tendency to vary in form is peculiar, among the Eunotie I 
have seen, to this species, E. Triodon and to E. begebba, Kiit- 
zing. It is totally absent in the common fossil forms of £. 
Tetraodon and E, Diadema, which hardly vary at all, save in 
size, 

It appears to me that this fact, especially when we consider 
that all these species often occur together, as, for example, in 
the Mull deposit, where FE. Triodon, though not frequent, is 
just as variable as in the Bergmehl under consideration, 
demonstrates that these species are really distinct, and not, as 
some have conjectured, varieties of one, which may present 
one, two, three, four, five, six, seven, or more prominences. 
If all belonged to one species, ‘all should be alike variable or 
alike poneeinh, whereas some vary ad infinitum, others not at 
all, in form at least. Nor can it be said that such a form as 
E. Triodon is developed, as a variety, only under certain cir- 
cumstances; for in the Mull deposit it occurs with all its 
peculiarities, and therefore the supposed circumstances must 
have occurred; and yet, in that deposit, Z. Tetraodon and 
E. Diadema are much more abundant, and show no tendency 
to vary inform. But these two last-named species are absent 
from this Lapland deposit, where LE. Triodon abounds. It 
seems to me that these facts settle the question as to the 
species named, which must be held to be true and well- 
marked species; one of the characters of E. Triodon and of 
E. begebba being a tendency to vary in form, while fixity of 
form characterises E. Tetraodon and E. Diadema. 

This Laponian deposit also contains £. serra, and I think 


Grecory, on Fossil Diatomacee. 105 


I have seen E. heptodon. __E.. serra seems to be confined to 
Scandinavian deposits. 

Although differing from the Mull deposit in regard to the 
forms I have named, and also some others, this Bergmehl 
agrees with it in many points, as in the abundance of Navicula 
rhomboides and N. serians, that of many Pinnularie, of Gompho- 
nema coronatum, of several Cymbelle, Stauroneides, Tabellaria, 
Orthosire, and other forms, but especially in the presence of 
Eunotia incisa, first observed by me in the Mull earth. The 
variety 6 is here the more frequent. 

There is another form, common to these two deposits, 

which, so far as I know, has not been described. It is an 
aspect like a Synedra, long and narrow, straight in the middle, 
and having the ends curved opposite ways. which gives to it 
a sigmoid character. I am inclined, however, to suppose it 
to be a Nitzschia, for while I cannot make out the transverse 
strie of Synedra, 1 can see a row of puncta on each margin 
in some specimens. It is, however, quite distinct from 
N. sigmoidea. 1n the Mull earth it is generally broken, so that 
we see only one-half; but I have found several entire ex- 
amples. In the Lapland deposit it is more frequent, and 
often entire, although from its slender proportions it is apt to 
be broken, and fragments also occur. As we have already 
Nitzschia sigmoidea and N. sigma, this form, if it be a 
Nitzschia, may be called N. sigmatella. 
_ I have still to notice a form occurring in this Lapland Berg- 
mehl, which, so far as I have been able to ascertain, is un- 
described. It is narrow and of considerable length, but bent 
into the form of a sickle, or nearly a semicircle. It is slightly 
attenuated at the rather acute apices, and has very strong and 
distinct, though rather fine, transverse strie. It approaches 
more nearly to Eunotia arcus, as figured by Smith, but differs 
entirely from it, in being much more curved, in the absence 
of the characteristic prominence in the so-called ventral 
surface, and in its having much stronger and more distinct 
strie, all of which characters combined give it an entirely 
peculiar aspect. Taking it, for the present, to be a Eunotia, 
I propose for it the name of Eunotia falx, or E. falcata. 

I would now direct attention to a deposit, of which speci- 
mens were sent to me by Mr. Norman, under the name of 
Liineburg. It is well known that there is an extensive de- 
posit on the Liineburg heath, in Hanover, and one part of it 
is known as the earth or Bergmehl of Oberrohe, near Liine- 
burg, another as that of the Liineburg heath. These I find to 
be quite distinct from the deposit of which I now speak, as 
obtained from Mr. Norman; for this, as I have found, has a 


106 Greeory, on Fossil Diatomacee. 


composition absolutely identical with that of the Lillhagesjon 
Lapland deposit I have described. Not only the species are 
the same, but they are in the same proportions. In both 
Eunotia triodon presents in abundance its strange variations ; 
in both the long sigmoid form, and also the sickle-like form, 
occur, 

In short, I can detect no difference between these two de- 
posits ; besides the forms I have named, both contain Eunotia 
tncisa, chiefly var.;8; and both alike contain such forms as 
Eunotia serra, Tetracyclus lucustris, and others, inasmuch that 
I think it more probable that one of them has been misnamed, 
than that two deposits, in places so distant as Liineburg in 
Hanover, and Lillhaggsjon in Lapland, should be identical in 
composition. Since all the specimens of earth from Oberrohe 
near Liineburg, and the Liineburg heath, that I have examined 
(and I have seen several different specimens in the natural 
state), differ from the Lapland earth, and since the Lapland 
earth is referred to its locality by the Zurich Association, I 
conclude that the earth in Mr. Norman’s hand is really not 
from Liineburg, but from Lapland. Perhaps there may be a 
place called Liineburg in Lapland, near Lillhaggsj6n ; but this 
1 have not been able to ascertain. In the mean time, this 
so-called Liineburg deposit will supply observers with the 
two forms I have now described. I have noticed it in some 
other forms which I believe to be undescribed ; to these I 
shall returt on some future occasion. 


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