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QUARTERLY JOURNAL 



MICROSCOPICAL SCIENCE. 



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QUARTERLY JOURNAL 



MICROSCOPICAL SCIENCE. 



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

AND 

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

VOLUME I. 
tttb 33toobcuts, l^it^ograp^it anb photographic ^latts 





LONDON: 

SAMUEL HIGHLEY, 32, FLEET STREET. 

1863. 






bOHDON : PRINTED BV W. CLOWEi) AND SONS, STAMFORD STREET. 



INDEX TO JOURNAL. 

VOLUME I. 



A. 



Achromatic condenser, on a new, by 

G. L. Riddell, 237. 
Acthwphrys Sol, description of, by A. 

Kollikef, 25, 98. 
Animalcule new, on a, 295. 
Animalcules red, in food, 144. 
Aracbnida on the circulation of the 

blood in, by Emile Blanchard, 279. 
Ascidians, existence of cellulose in the 

tunic of, 22. 

,, microscopical and chemical 

examination of the mantle of, 34, 1 06. 
Ayres, Dr., P. B., on certain pecu- 
liar structures in the placenta of the 

bitch, 299. 

,, ouVibriones, 300. 

Aymot, T. E., on the " finder," 303. 

B. 

Barry, Dr. M., on muscular fibre, 240. 

Beale, Dr. L., on the construction of 
cells for preserving objects in fluids, 
54. 

,, on substances of extraneous 
origin in ui'ine, &c., 92. 

Bennett, Dr., on leucocythemia, re- 
view of, 130. 

,, an introduction to clini- 

cal medicine, review of, 223. 

Binocular microscope, notice of, 236. 

Bitch, certain peculiar structures in 
the placenta of 299. 

Bird, Dr. Golding, remarks on the 
preparation of the polypidoms of 
zoophytes for microscopical exami- 
nation, 85. 

Blanchard, Emile M., observations ou 
the circulation of the blood in 
Arachnida, 279. 

Blood human, occurrence of nucleated 
red corpuscles in, 145. 

Bothrenchyma, on the formation of. 
Dr. T. Inman on, 57. 

Branchipns slaynalis, 277. 

Bridgman, W. K., on the "finder," 
303. 

Brightwell, T., on the genus Tricera- 
tiiim, with d«'Scriptious of figures of 
tlie species, 245. 
VOL. I 



British Association, Belfast Meeting, 

Sept. 1852, 61. 
Busk, catalogue of marine polyzoa, 

notice of, 136. 

„ on the occurrence of nucleated 

red corpuscles in human blood, 145, 



C. 



Cells for preserving objects in fluid, 

new method of constructing them, 

Dr. L. S. Beale on, 54. 
Celhilaria avicularia, 87. 
Cephalopoda, retina of the, 269. 
Chemistry, physiological atlas of, by 

Dr. O. Fuiike, notice of, 137. 
Chlroceplialus diaphaiiiis, 277. 
Clubfoot, Quekett on the condition of 

the muscles in. 130. 
Cobbold, Dr. T. S., on the embry- 

ogeny of Orchis masenla, 90. 
Coi-uea of the eye in insects, remarks 

on by J. Gorham, 76. 
Cryptococcus ylutinis, 235. 
Ctenoglossa, 171. 
Cynthia microcosmiis, 107. 
Colouring matter in animals identical 

with the chlorophyll of plants, 278 



D. 



Dactj/loijlossa, 1 73. 

Daphnidffi, physiological remarks on 

by Dr. W. Zenker, 273. 
Dentine, certain appearances in, by S. 

.T. A. Salter, 252. 
Diatomaceaj, synopsis of the British 

by Rev. W. Smith, notice of, 225. 
,, ., some new forms 

of, by Mr. Shadbolt, 311. 
Didevimim candidum, 107. 
Dotted tissue, ou the formation of, 57. 
Diatoraaceous earth, found in the 

Island of Mull, Dr. W. Gregory on, 

242. 
Diatoma elonyatiim, 21. 

,, viilyare, 21. 

Drapernaldia (jlonwrata, 20. 
Drepano(il(iss(i , 172. 
Drinking waters, microscope as a test 

of the purity of, 60. 

2 A 



314 



INDEX TO JOURNAL. 



E. 



Echinococcus veterinorum, the tnie 
structure of, T. H. Huxley on, 239. 

Encephaloid tuberculous deposit, the 
microscopic characters of, l"i7. 

Eyes of insects, the cornea of, J. 
Gorham, M.R.C.S.E., on, 76. 

F. 

"Finder," description of by J. Tyr- 
rell, 234. 

„ by E. G. Wright, 302. 
„ by T. E. Aymot, 303 
„ by W. K. Bridgman, 304. 
Flustrafoliacea, 86. 
,, truncata, 88. 
Funke, Dr. O., atlas of physiological 
chemistry, 137. 

G. 

Gemellaria loricata, 86. 

Geranium, structure of the epidermis 

of the petal of, 56. 
Glass, thin, for covers, G. Jackson 

ou, 141. 
Goitre, excess of colourless corpuscles 

occurring in cases of, 176. 
Gold-dust under the microscope, 144. 
Gomphonema cristatum, 21. 
„ ciirvatiim, 21. 

Gorham. J., remarks ou the cornea of 

the eye in insects, 76. 
Gosse,P.H.,onthestructure, habits, and 

development of Mclicerta rinyeiis,~\. 
Gray, Dr. J. PI, on the teeth on the 

tongues of Mollusca, 1 70. 
GreyarincB, on the, by Dr. F. Leydig, 

206. 

„ descriptions of various spe- 
cies of, 211. 
Gregory, Dr. W., notice of a diatoma- 

ceous earth found in the Island of 

Mull, by, 242, 



H. 



Ilair, human, and of animals, M. A. 

Moriii on, 136. 
Ifdicriiim halicinnm, 88. 
I la III if/ los.'id , 172. 

Hannover, Dr. Adolphe, on the con- 
Htruction and uses of the microscope, 
review of, 284. 
Harvey, Dr. W. H., Sea-side Book, 

review of, 280. 
Heufrey, A., on vegetable cells, 233. 
,, on the vinegjir plant, 2.'!.5. 

„ translation of Molil on 

vegetable cells, review 
of, 287. 



Herapath, Dr., on optical properties 
of a salt of quinine, 57. 

Herbst, experiments on the transmis- 
sion of intestinal worms, 209. 

Highley, S., Jun., description of achro- 
matic gas-lamp, 143. 

„ on the practical appli- 

cation of Photography to the illus- 
tration of works on Microscopy, 
&c., 178. 

„ microscope camera, 306. 

Histology, lectures on, by Quekett, 
notice of, 40, 122. 

Holland, Dr. T.S., excess of the colour- 
less coi-puscles of the blood (Leu- 
cocythemia) occurring in cases of 
goitre, 176. 

Huxley, T. H., on the existence of 
cellulose In the tunic of ascidians,22. 
„ on the development of 

the teeth and on the nature and 
import of Nasmyth's "Persistent 
Capsule," 149. 

,, Lecture on the identity 

of structure of plants and auimals, 
307. 

,, on the structure of 

Echinococcus veterinorum, 239. 

Hydrodiclyon, 233. 

I, J. 

Infusoria, in morbid discharges, 146. 

Infusorial animalcules, history of, by 
Pritchard, review of, 229. 

Innum, Dr. T., on the fonnation of 
Bothrenchijina, or dotted tissue, 57. 
„ ou the structure of the 

epidermis of the petal of the gera- 
nium, 56. 

„ on desquamation of pul- 

monary air-cells, 58. 

Insects, remarks on the cornea of the 
eye in, 76. 

Intestinal worms, experiments on the 
transniii-sion of, by JNI. Herbst, 209. 

Iris, contractile tissue of, 8 

Jackson, G., on thin glass-covers, 141. 

Jenner, Dr. W ., on a curious case of 
colloid disease in the abdomidal 
viscera, 126. 

Jones Wharton, on muscular fibre- 
cells, 9. 

K. 

Kblliker, on muscular tissue, 9. 

„ Manual of Human Histo- 
logy, notice of, 133. 

,, Description of Actinnphrys 
Sol, 25, 98. 

„ Contributions towards a 
knowledge of the lower uuimuls, 
211, 



INDEX TO JOURNAL. 



315 



Lacunae in bone, Quekett on, 123. 
Lamp, description of achromatic gas, 

by S. Highley, 143. 
Landsborough, Eev. Dr., popular 

history of British zoophytes, notice 

of, 136, 
Leeuwenhoek, on the lenses of the 

silkworm's eye, 82. 
Legg, Mr., on sponge sand, 311. 
Leucocythemia, or -white-cell blood, 

by Dr. J. H. Bennett, notice of, 

130. 

„ occurring in cases of 

goitre, by Dr. T. S. Holland, 17C. 
Leydig, D. F, on the Psorospermia 

and Gregarina, 206. 
Lister, Joseph, obsei*vations on the 

contractile tissue of the iris, 8. 

„ on the muscular tissue 

of the skin, 262. 
Liver, on the capillaries of, 231. 
Loven, on the teeth of marine Mol- 

lusca, 171. 
Lynceus, 276. 

M. 

Mackerel, teeth of, 158. 
Mantell, Dr. A. G., obituary of, 148. 
Melicerta rinyens, the anatomy of, by 
Prof. Williamson, 3, 65. 

„ on the structure, 

habits, and development of, by P. 

H. Gosse, 71. 

Microscope camei'a, S. Highley, 306. 

„ the, and its application, by 

Dr. H. Schacht, review of, 46. 

„ on the construction and 

uses of, by Dr. Adolphe Hannover, 
review of, 284. 

„ curiosities of, by Rev. J. 

H. Wythes, notice of, 138. 

„ mode of determining the 

optical power of a, 292. 

,, binocular, Prof. Riddell's, 

304. 
Microscopic plants and animals, lo- 
calities of, 305. 
Microscopical Society of London 
1852-3, proceedings of, 61, 147, 242, 
311. 

,, objects, localities for 

finding, 231. 

„ re-agents, Dr. Parkes 

on, 139. 
Microscopist, the, a complete Manual 
of the use of the microscope, by T. 
H. Wytiies, notice of, 51. 
MoUilics ossiiim, Quekett on, 123. 
Momm produjioscij 144. 
Mohl, Hugo von, principles of the 



anatomy and physiology of the 
vegetable cell, review of, 287. 

Moriu, A., on the microscopic appear- 
ances in the hair of man and ani- 
mals, 136. 

Morbid discharges, infusoria in, 144. 

Miiller, H., on the structure and func- 
tions of the retina, 269. 

Muscular fibre, microscopic observa- 
tions on, by Dr. J. L. Prevost, 135. 
„ Dr. ]NL Barry on, 240. 

Muscles, fatty degeneration of. Que- 
kett on, 124. 

N. 

Nasmyth's "Persistent Capsule," on 

the nature of, 149, 153. 
NaviculcE, mode of isolating, by Dr. 

Redfern, 235. 

0. 

Obituary of Dr. A. G. Mantell. 

„ Dr. J. Pereira, 243. 
Objects for microscopical examination, 

hints on the collecting of, 17. 
OdontogJossa, 173. 
Opaque objects, a new method of 

illuminating, 23". 
Oplatoglossa, 173. 
Orchis masciila, on the embryogeny 

of, by Dr. Cobbold, 90. 



P. 



Pamphagus, 298. 

Parkes, E. A., M.D., on microscopical 
re-agents, 139. 

Pathological Society of London, re- 
view of proceedings of, 126. 

Pereira, Dr. J., obituary of, 243. 

Phallusia, 23, 35, 109. 

PJialhisiu gelatinosa, 107. 

Pflanzenzelle Die, der innere Bau und 
das Leben der Gewiichse, Dr. H. 
Schacht, review of, 214. 

Photographic delineation of micro- 
scopic objects by artificial illumina- 
tion, 165. 

Photography, practical application of, 
to the illustration of works on 
Microscopy, &c., 178. 

riiimularia jfalcata, 88. 

Polypidoms of Zoophytes, remarks on, 
by Dr. G. Bird, 85. 

Polyzoa, catalogue of marine, by G. 
Busk, notice of, 136. 

Prevost, Dr. J. L., on muscular fibre, 
135. 

Psorospermia, on the, by D. F. Ley- 
dig, 2()ii. 

Pijrosoma, 23. 



316 



INDEX TO JOUENAL. 



Q. 

Quain, Dr. R., on the distinctive cha- 
racters between encephaloid and 
tuberculous deposit, 127. 

Quekett, Lectures on Histology, re- 
view of, 40, 122. 

Quinine, optical properties in a salt 
of, 57. 

R. 

Rainey, G., on the capillaries of the 

liver, 231. 
Raschkow, researches on teeth, 154. 
Ke-agents, useful in microscopical 

inquiries. Dr. Schacht on, 47. 

,, Dr. E. A. Parkes on, 

139. 
Reports of Juries, Exhibition of 

Works of Industry of all Nations, 

1851,219. 
Retina, structure and functions of the, 

by H. Muller, 2G9. 
Shachif/losAa, 171. 
Rhipidoglossa, 171, 175. 
Riddells, Prof., binocular microscope, 

304. 
Royal Society, Proceedings of, 243. 



Salter, S.J. A., on certain appearances 
in dentine, 252. 

Sarcina ventriculi, Dr. Bence Jones 
on, 128. 

Schacht, Dr. H., on the microscope 
and its applications, review of, 46. 

,, the vegetable cell, 

the internal structure and life of 
plants, review of, 214. 

„ on the microscopical 

and chemical examination of the 
mantle of certain Ascidians, 34, lOG. 

Schultze, M. Max, on the identity of 
a colouring matter present in several 
animals with the chloropliyll of 
plants, 278. 

Sea-side Hook, by Dr. VV, H. Harvey, 
review of, 280. 

Serous cysts in the kidney, 128. 

Serlularia abie.timi, 87. 
„ operculnid, 87. 

,, Jilictda, 38. 

Shadbolt, G., hints on the collecting 
of objects for microscopical exami- 
tion, 17. 

,, on the i)hotographic de- 

lineation of microscopic objects by 
urtificiul illumination, I ('5. 



Shadbolt, G. on some new forms of 
Diatomacea; from Port Natal, 311. 

Siebold, C. T. von, on unicellular 
plants and animals, 111, 195. 

Skate, development of teeth of, 151. 

Skin on the muscular tissue of, J. 
Lister, 262. 

Sponge sand, on, by M. S. Legg, 311. 

T. 

Teeth, development of, by T. H. Hux- 
ley, 149. 

Tongues of Mollusca, on the teeth of, 
by Dr. J. E. Gray, 170. 

Tanioglossa, 173. 

Toxoglossa, 172. 

Triceratiiim, on the genus, by T. 
Brightwell, 245. 

Trichina spiralis, 209. 

Tyrrell, J., description of a "finder" 
for the microscope, 234. 

U, V. 

Unicellular plants and animals, C. 

T. von Siebold on. 111. 
Urine, substances of extraneous origin 

in, 92. 
Vegetable cell, the internal structure 
and life of plants, &c., by P. H. 
Schacht, review of, 214. 

,, on a peculiarity in the 

thickening layers of, by A. Henfrey, 
233. 

„ principles of the ana- 

tomy and physiology of, by Hugo 
von Mohl, review of, 287. 
Yibriones, 300. 
Vinegar plant, the history of, by A. 

Henfrey, 235. 
Vortex viridis, 278. 

W. 

Williamson, on the anatomy of Meli- 

ceria rinqens, 3, 65. 
Wright, E; G., on a "finder," 302. 
Wythes, Rev. J. H., curiosities of the 

microscope, review of, 138. 

X, Y, Z. 

Zenker, Dr. W., Physiological re- 
marks on the Daphnida-, 273. 

Zoological Society, proceedings of 
1852, 239. 

Zoophytes, on the polypidoms of, 8.5. 
,, popular Insf^r* of Biitisb. 

notice of, 13(). 



PREFACE. 



Recent improvements in the Microscope having rendered that 
instrument increasingly available for scientific research, and 
having created a large class of observers who devote themselves 
to whatever department of science may be investigated by its 
aid, it has been thought that the time is come when a Journal 
devoted entirely to objects connected with the use of the Micro- 
scope would contribute to the advancement of science, and secure 
the co-operation of all interested in its various applications. 

The object of this Journal will be the diffusion of informa- 
tion relating to all improvements in the construction of the 
Microscope, and to record the most recent and important re- 
searches made by its aid in different departments of science, 
whether in this country or on the continent. A department of 
the Journal will be given to reviews of works, or those parts of 
works which are devoted to subjects of inquiry in which the 
Microscope is employed. It is the wish of the Editors to con- 
duct this department in a friendly spirit, regarding all who 
labour honestly in the field of science as co-workers for the 
common good. In order to gather up fragments of information, 
which singly might appear to be useless but together are of 
great importance to science, the Editors have opened a depart- 
ment for short notes, memoranda, and correspondence, to which 
they would especially invite the attention of their scientific 
friends, as they believe there are few possessors of a Microscope 
who have not met with some stray fact or facts which, published 
in this way, may not lead to important results. They hope 
also to relieve the graver and more strictly scientific matter 
of the Journal by lighter contributions, such as will be found 
useful to the beginner, not uninteresting to the advanced ob- 
server, and of interest perhaps to the general reader. 

In a Journal of this nature illustrations are indispensable, as 
it is difficult to convey an accurate idea of objects observed by 
description alone ; but as it is impossible to give a fixed amount, 
the Publishers have determined to afford, on an average, with 

VOL. T. B 



2 PREFACE. 

each number, four lithographic plates, and such woodcuts as 
may be necessary ; and they congratulate themselves in having 
secured for this department the services of Mr. Tuffen West, as 
their artist, to whose plates in the present number they may 
confidently appeal, as examjdes of the manner in which they 
wish to illustrate the Journal in future. 

In announcing the objects they have in view, the Editors 
would especially call attention to the connexion of this Journal 
with the Microscopical Society of London, as it is mainly 
through the readiness expressed by the Council of that Society 
to co-operate with the Proprietors and Editors, in order to dif- 
fuse more widely, and to publish more regularly, their Trans- 
actions, that the Journal owes its existence in its present form. 

The papers published under the head of ' Transactions of 
the Microscopical Society of London ' are selected by the 
Council of that Society ; for its other contents and general con- 
duct the Editors are alone responsible. 

It is, perhaps, hardly necessary to apologise for the title of 
the Journal, as the term " Microscopical," however objection- 
able in its origin, has acquired a conventional meaning by its 
application to Societies having the cultivation of the use of the 
Microscope in view, and so fully expresses the objects of the 
Journal, that it immediately occurred as the best understood word 
to employ. It will undoubtedly be a Journal of Microscopy and 
Histology ; but the first is a term but recently introduced into 
our language, and the last would give but a contracted view 
of the ol)jects to which the Journal will be devoted. 

As the success of their undertaking must mainly depend on 
the cordial assistance and co-operation of those who are engaged 
in prosecuting microscopical investigations, the Editors would 
urge uj)on them the importance of their assistance in making 
known the nature and objects of ' The (Quarterly Journal of 
Microscopical Science,' and in becoming contributors to its 
pages. 



QUARTERLY JOURNAL 

OF 

MICROSCOPICAL SCIENCE. 



ORIGINAL COMMUNICATIONS. 

On the Anatomy of Melicerta rixgens. By W. C. Wil- 
liamson, Esq., Professor of Natural History, Owen's Col- 
lege, Manchester. 
The appearance of large numbers of the Melicerta ringens 
amongst the plants growing in my Vallisneria trough has 
afforded me an opportunity of subjecting this fine Rotifer to a 
careful examination ; the result has been the elucidation of 
some portions of its anatomy Avhich had not been fully worked 
out by Leeuwenhoek, Schaffer, Dutrochet, or Ehrenberg. 

The ordinary appearance of this object is too well known to 
need a description. Its general aspect, when removed from its 
tessellated case, is represented by fig, 14, PI. I. The four fla- 
belliform rotatory organs (14 a), when forced out of the body 
(into which they can be withdrawn) and fully expanded, are seen 
to be clothed with ciliae over their entire surface ; those fringing 
the margin being the longest and most conspicuous. On one 
side of the neck are the two small incurved processes (14&), 
which Schaffer calls the lips. When the animal withdraws 
the rotatory organs into the fore part of its body, which it does 
when alarmed, these hooks constitute two of the most prominent 
points of its body. On the opposite side to that occupied by 1| 
these appendages there is a fifth and smaller rotatory organ (I c), -1. 
with a thickened margin, from which radiating bands proceed * .. 
inwards to its point of attachment. This organ is also ciliated. V 
On each side of it, and opposite to the two hooks, there are 
two long tentacles (14 r/), the homologues of organs which are 
common amongst the Rotifera. To these Ehrenberg has 
assigned respiratory functions, whilst Dujardin regards them 
as more closely resembling the antennce and palpi of the 
Entomostraca. When one of these tentacles in the Melicerta 
is fully protruded it is seen to be terminated by a brush of 
fine divergent setae (15 rt), implanted on the convex side of a 
small deltoid body (15 Z»); from the flat side of this latter 

B 2 



4 ON THE ANATOMY OF MELICERTA KINGEXS. 

appendage there proceeds along the interior of the tube, 
towards the body of the animal, a delicate muscular band 
(15 c), which, by its contractions, draws the deltoid body back- 
wards, thus inverting the extremity of the tube and forming a 
double sheath protecting the setae (16). This inversion of 
the tube was, I believe, first noticed by Dutrochet. The 
whole apparatus is, as suggested by Schaffer, very similar to 
that seen in the tentacles of the snail, and appears to consti- 
tute a tactile rather than a respiratory organ. This is rendered 
the more probable by the fact, that when the animal first 
emerges from its tessellated case, the extremities of these two 
tentacles are the first parts that make their appearance, the two 
curved hooks being the next. The setae are usually half- 
drawn into the inverted tentacle, but they project sufficiently 
forward to constitute delicate organs of touch, supposing the 
deltoid body into which they are inserted to be endowed with 
sensibility. The animal cautiously protrudes these tentacles 
Ijefore it ventures to unfold its rotatory organs, but it does 
not direct them in an exploratory manner from side to side, as 
an insect does its antennae. 

The alimentary canal commences with a small oral orifice, 
situated near the centre of the sinuated disk formed by the 
rotatory organs. It opens into an oesophagus, which conducts 
the food down to the gastric teeth (14 e). These are implanted 
in a large conglobate cellular mass, which completely invests 
them. Their appearance is accurately represented by fig. 17 : 
they consist of two essential portions — a pair of strong crush- 
ing plates, which bruise tlie food, and various appendages 
affording leverage and facilitating the action of the muscles 
upon them. I he crushers are two broad elongated plates 
(17 a), each being about l-800th of an inch long, and separated 
from eacli other at the mesial line, near which they become 
much thickened. Fi'om each of these plates there proceed 
laterally numerous parallel bars (17 i), all of which are some- 
what thickened at their inner extremities where they are 
attached to tlie plates, whilst at their opposite ends they are 
united witli the otliers of the same side by a curved con- 
ncdin;,' bar (i7c), from the outer sides of which are given off 
various loops and processes. The three uppermost of these 
bars are the largest, the rest gradually diminishing in size and 
strength as we descend, the inferior ones being almost invisible. 
I'Voin the upper extremities of the two crushers there project 
uj)w.irds and l)ackwards two slender prolongations (17 r/), 
united by a kind of double hinge-joint near their apex, 
where they not only |>Iay upon each other, but also on 
a thini small central iixcd point (17 e) lodged in a little 



ON THE ANATOMY OF MELICERTA RINGENS. 5 

conglobate cellular mass. Ehrenberg only describes three 
transverse bars on each side, which he regards as teeth. It is 
obvious that he has only noticed the three upper and larger 
pairs. It is equally evident that these transverse teeth, as he 
terms them, do not move upon the strong longitudinal plates, 
as he imagines, but are firmly united with them. Muscles are 
either attached to the divergent peripheral processes, or to the 
cellular mass in which these processes are imbedded, causing 
the entire apparatus to separate into two parts along the mesial 
line, by means of the hinge joint at 17 c, the so-called teeth 
merely transmitting the motor force to the two longitudinal 
plates. These latter appendages are thus made to play upon 
each other with great power, and act as efficient crushers, 
bruising the food before it passes into the stomach, as is the 
case with the gastric teeth of the Crustacea, From the above 
remarks it will be seen that, though in its construction the 
dental apparatus is more complex than is represented by 
Ehrenberg, in its mode of working it is less so. 

The conglobate organ in which this apparatus is imbedded 
is transparent, and composed of numerous large cells, each of 
which contains a beautiful nucleus, with its nucleolus. The 
cells are only seen when the organ is ruptured between two 
plates of glass, when they readily separate from one another ; 
but the nuclei, with their contained nucleoli, are distinctly 
visible in the living animal. Delicate muscular threads most 
probably penetrate this organ to reach the dental apparatus, 
though I have not vet detected them. 

After passing the dental organs, the food enters an elongated 
stomach (14 y), with very thick pulpy parietes. In young ex- 
amples these walls are colourless and transparent, but in more 
matured specimens they exhibit a bright olive-yellow hue. 
The whole cavity, as well as the oesophagus leading into it, is 
lined with ciliae, which are constantly playing. On rupturing 
this organ we perceive that it is composed of a thin pellucid 
external membrane, which exhibits no structure, but within 
which is a thick layer of large turgid epithelial cells. These 
are easily detached from the membrane, when each one 
is seen to be spherical, containing numerous yellow granules, 
and very often a nucleus with its nucleolus. The ciliae are 
attached to one side of these cells, the great length of these 
appendages constituting the most marked feature of the struc- 
ture. It often equals the entire diameter of the cell. Some 
of the cells exhibit no ciliae ; others are only furnished with 
them on one side ; whilst a few appear to be fringed with 
them throughout their entire circumference. I presume that 
in the latter case the cells have projected considerably into 



6 ON THE ANATOMY OF MELICERTA RINGENS. 

the cavity of the stomach. The yellow granules are absent 
from those of young animals, showing clearly that it is these 
contained granules that give the colour to the parietes of the 
stomach in matured individuals. The connexion between the 
cells is very slight, since but little pressure suffices to detach 
them from their position without marring their integrity. By 
their aggregation they constitute a true epithelial structure, 
lining a thin and apparently structureless membrane ; but from 
the constant automatic movements of the viscus, it is possible 
that this latter membrane may contain minute muscular fibrillzp. 
The great thickness of the epithelial layer, as compared with 
the entire diameter of the organ, is curious. Whilst the latter 
averages about l-250th of an inch, the former is often not less 
than l-1500th, or l-6th of its entire diameter. The cells 
when detaclied varj in size, from a diameter of 1-lOOOth to 
l-1600th of an inch : one of these, which was fringed with 
cilia', 1-lGOOth of an inch long, is represented in fig. 18, its 
nucleus b^ing about l-7000th of an inch. After being de- 
tached, some of the ciliated cells floated slowly away, like so 
many animalcules. 

This stomach appears to be chiefly a receptacle for the food. 
From time to time, especially when the viscus is distended, a 
porticm of its contents pass down into a lower stomach (14 g\ 
which is separated from the upper one by a marked though 
varying constriction. This second stomach is also lined with 
cilia?, which are even longer than those of the upper viscus ; 
but th(? parietes are very much thinner and more transparent, 
the cells being less easily traced. The diameter of the organ 
is nearly the same in each direction, so that it is almost sphe- 
rical. Tlie mass of food with wliich it is usually distended is 
constantly revolving, the motion being due to ciliary action. 
This process goes on for some minutes, after which the crea- 
ture contracts its body, and forces the entire exuviae out of the 
viscus into a long narrow cloaca, which terminates externally 
hy an anal outlet at 14 //. As it does this, it everts a consider- 
able portion of the cloaca ; thus almost Imnging the doacal 
i)utl(;t of the stomach to the exterior, and causing at the same 
time a large transparent protuberance (14 i) to be developed on 
the corresponding side of its body. At other times the crea- 
ture (an draw in these; appendages, so that scarcely any trace 
of a ( loacal canal is visible. 

Nearly on a level with these stomachs is the ovary (14 k\ an 
oblong organ, extending from near tlie oral orifice, superiorly, 
fi» the (cntn; of the lower stomach in the opposite direction. 
It is a pelliuid incinhranous l)ag, distended with graimlar 
protoplasm, in whi( h are dispersed numerous nucleolated nuclei. 



ON THE ANATOMY OF MELICERTA RINGENS. 7 

The oviduct consists of a prolongation of the membrane of the 
ovary. Tt winds round the inferior border of the lower stomach 
(14 / and Id b), and enters the cloaca near the point where the 
lower stomach opens into that excretory canal, 

I have sought in vain for any organ to which the functions 
of a spermatic gland can be indisputably assigned. Immedi- 
ately beneath the lower stomach and the contiguous oviduct, 
there is an elongated pyramidal organ (14 m and 19 d), appa- 
rently hollow, the thick extremity of which is directed towards 
the ovary, and its opposite attenuated portion passes upwards 
towards the cloaca, between the oviduct and the general inte- 
gument. Into the thick inferior extremity of this organ there 
are inserted, exactly opposite to each other, two long cylin- 
drical appendages, which diverge, and, passing on each side of 
the alimentary canal, proceed towards the upper part of the 
body, where their extremities are not easily traced. In but 
one instance I observed them to terminate in a series of irre- 
gular convolutions near the base of the two tentacles. Though 
not yet capable of demonstration, it appears probable that 
this curious appendage may be a filamentous spermatic tube, 
resembling those found in many of the articulata. That they 
are tubes, and not muscular bands, appears unquestionable ; 
and as they have obviously a direct connexion with the cloaca, 
they might easily discharge a fertilising secretion into that 
common excretory canal, from which it would find its way to 
the ovary thi'ough the oviduct. 

The muscular system is developed in an interesting manner. 
Distinct muscular bands occur at intervals in the common 
tegument, concentrically encircling the entire organism. Their 
action is easily observed. Still larger and more distinct fasci- 
culi run lengthwise ; some of these proceed from the upper 
part of the visceral cavity to the base of the tail or peduncle, 
where (19) they are inserted into a thickened portion of the 
integument. Others, taking their rise from various parts of 
the body, proceed along the caudal prolongation (14 ji, 19^, and 
20 a), and are inserted into a little concavo-convex body 
(14 0, 20 b) at its extremity. This latter gi'oup of muscles is 
easily examined, owing to the exceeding transparency of the 
integument. On rupturing the muscular fasciculi trans- 
versely, we perceive that each one is invested by a delicate 
sarcolemma (21 a). This is well seen at the upper part of the 
tail, where, on the contraction of the muscle, the non-elastic 
sarcolemma becomes corrugated (21 b), and only recovers its 
smooth aspect when the muscle becomes relaxed. These rugae 
of the sarcolemma must not be confounded with the transverse 
stria? of the muscular fibre. When one of these muscular fas- 



8 ON THE ANATOMY OF MELICERTA RINGENS. 

ciculi is drawn out at full stretcb, its surface is seen to be 
marked at very regular intervals bj dark transverse bars (22). 
Each fasciculus has a diameter of about l-3500th of an inch, 
and the transverse striae recur at distances of about l-9000th. 
These intervals are, of course, rather larger than those seen in 
the fasciculi of human voluntary muscle. The bars extend 
entirely across the fasciculus. There can be no doubt that 
this structure is the homologue of what occurs in the voluntary 
muscles of the higher animals. 

The general integument consists of a thin and very trans- 
parent membrane. In this are embedded numerous concentric 
muscular bands already referred to. In the skin surrounding 
the visceral cavity there are also longitudinal fibres ; whilst, in 
the rotatory organs, corresponding threads, which I presume to 
be muscular, interlace in various directions. 

The small organs which are so common amongst the Roti- 
fera, and which Ehrenberg regards as nervous ganglia, are 
abundant in the McUcerta ; but they afford no countenance 
to the hypothesis of the great Prussian Professor. They 
apj)ear to be nothing more than small cells or vesicles formed 
of granular viscid protoplasm, very similar to that into which, 
as we shall immediately find, the yolk of the e^g becomes 
divided. Sometimes they float freely in the fluid which dis- 
tends the integument and bathes the viscera (14 ^). At others, 
thin du( tile threads pass from one vesicle to another, as seen 
in fig. 19 /?, where these objects are delineated as they appeared 
in one individual, in the clear space immediately below the 
viscera. In this case they are more abundant than is usual. 
There is no uniformity in their arrangement in different indi- 
viduals. They differ as widely as is possible in their size, 
number, and distribution. So far from being nervous vesicles, 
tliey appear rather to be cells, modified into a rudimentary 
form of areolar tissue. Tliat they are hollow vesicles or cells, 
very viscous, readily cohering, and, owing to this coherence 
readily drawn out by the movements of the various organs to 
which they are attached, are facts capable of easy demon- 
stration. 

[To be continued.] 



Observations on the Contractile Tissue of the Iris. By 
Joseph Lister, Esq., B.A. 

~'^<Sljj, ()' R knowledge of the cause of the movements of the iris was 
till within the last few years in a very unsatisfactory condi- 
()on. That this organ possessed contractile fibres was a 
matter of inference, not of direct observation. In the third 



CONTRACTILE TISSUE OF THE IRIS. 9 

part of the last edition of Quain's Anatomy, published in 
1848, we find it stated (p. 915) that the radiating and circular 
fibres of the iris are generally admitted to be muscular in their 
nature, but the gi'ounds for that admission are not mentioned. 
Mr, Bowman's Lectures on the Eye, delivered in the summer 
of 1847, and published in 1849, show us that the then state of 
histology in this country did not enable that accomplished 
microscopical anatomist to identify the fibres of the iris with 
other plain (unstriped) muscular tissue. At page 49 he says, 
" The fibres which make up the proper substance of the iris 
are of a peculiar kind, very nearly allied to the ordinary un- 
striped muscle, but not by any means identical with it," He 
afterwards goes on to argue that, as we know that the organ 
changes its form, and as its vessels are so distributed that it 
cannot be erectile, we have no other resource than to consider 
its fibres contractile, which conclusion he supports by refer- 
ence to the striped fibres in the iris of birds and reptiles. 

In 1848 Professor Kolliker announced to the world his 
grand discovery of the cellular constitution of all plain mus- 
cular tissue, in a full and elaborate paper in the ' Zeitschrift 
fiir Wissenschaftliche Zoologie.'* At p. 54 of the first part 
of the first volume of this journal, after speaking of the arrange- 
ment of the fibres of the ciliary muscle, the sphincter pupillce, 
and dilator pupillae, he makes the following statement : — 
" The elements of all these muscles are undoubtedly smooth 
muscular fibres. In man I have but seldom succeeded in iso- 
lating the individual fibre-cells, but I have had more frequent 
success in the case of the sheep, Avhere I found them in the 
ciliary muscle, on an average, I -600th of an inch in length, and 
l-4000th to l-3000th of an inch in breadth. In man, in all 
these muscles one sees, as a rule, only parallel fibres projecting 

* Professor Kolliker may almost be said to have been anticipated in 
this discovery by Mr, Wharton Jones. Through the kindness of that 
gentleman, I have now before me two original drawings, made by him 
about the year 1843, of plain muscular tissue from the small intestine. 
In one of these the musciUar fibre-cells are characteristically shown, 
except that their nuclei are not apparent ; one of them is wholly isolated. 
In the other drawing, the alternate disposition of the fibre-cells is seen 
after the addition of acetic acid. He also observed, as he informs me, that 
the unstriped muscle of the oesophagus and stomach, and also of the 
uterus and other organs, consisted of similar elements — a fact which he 
yearly communicated to his class in his public lectures at Charing Cross 
Hospital. He was led, from a]i]iearances in the embryo, to infer that 
striped muscular fibre is originally composed of similar elements, which, 
in the process of development, are enclosed in a sarcolemma common 
to many of them, and become split into fibrilU'c. He thus accounted for 
the nuclei of striped muscular filirc, which, according to this view, arc the 
persistent nuclei of the primitive muscular fibre-cells, — J, L. 



10 OBSERVATIONS ON THE 

to a greater or less extent at the edges of small fragments of 
the tissue, these fibres exhibiting in abundance the well-known 
elongated nuclei, either with or without the aid of acetic acid. 
In man, the muscle of the choroid (ciliary muscle) has broader 
and more granular fibres and shorter nuclei than the iris. In 
the former the nuclei measm-e from 1 -2400th of an inch to 
l-lo3ord of an inch ; in the latter as much as l-1090th of 
an inch." 

Here, then, we have, so far as I know, the first and only 
recorded observation of tissue in the iris identical with ordi- 
nary unstriped muscle. 

It is to be remarked that, where he alludes in the passage 
above quoted to having in rare cases separated the individual 
fibre-cells of the muscular tissue. Professor Kolliker speaks of 
the three muscles (ciliaris, sphincter, and dilator) collectively ; 
in other words, that he does not tell us in plain terms that he 
has isolated the fibre-cells of the iris at all. Now, the ciliary 
muscle is confessedly easier to deal with than the iris. Mr. 
Bowman, who speaks so doubtfully of the fibres of the iris, 
says of the ciliary muscle, " the fibres are seen to be loaded 
with roundish or oval nuclei, often precisely similar to those 
of the best marked examples of unstriped muscle " (op. cit., 
p. 53). Another very eminent microscopical anatomist has 
informed me, as the result of his experience, that it was easy 
to identify the tissue of the ciliary muscle with that of other 
organic muscle, but that this had not been the case with the 
iris. That Professor Kolliker's isolation of the fibre- cells of 
the muscles of the eye was in reality confined to the ciliary 
muscle is rendered probable by the fact that, while the whole 
article quoted from shows a manifest desire on the part of its 
author to give all available detail, yet regarding the iris he 
mentions no facts requiring isolation of the fibre-cells for their 
determination ; while, on the other hand, he tells us that the 
fibre-cells of the iris are narrower than those of the ciliary 
muscle, and gives the length of the nuclei in the human iris — 
things which are very readily observed without isolation of 
the fibre-cells. His figures refer to the human ciliary muscle 
alone; and the only measurements given bv him of muscular 
fibre-cells from the eye refer to the same muscle in the sheep. 

It would seem, then, that with regard to the iris, Kolliker's 
proof falls short of the test of isolation of the fibre-cells. 

An operation for artificial pupil, by excision, performed by 
Mr. Wharton Jones, at University College Hospitid, on the 
1 1th of August of the present year (1852), placed in my pos- 
s(!Ssion a perfectly fresh portion of a human iris, anil, without 
knowing that Kolliker's observations had extended to the 



CONTRACTILE TISSUE OF THE IRIS. 1 1 

muscles of the eye, I proceeded to avail myself of this some- 
what rare opportunity of investigating the muscular tissue of 
the human iris. On placing under the microscope, four 
hours after the operation, portions of the tissue carefully 
teased out in water with needles, I found that some of the 
muscular fibre-cells had become isolated, and presented very 
characteristic appearances. I accordingly made camera lucida 
sketches of the finest specimens, which are reproduced on a 
smaller scale in the accompanying figures (see PI. I., fig. 7-11). 
I drew the last cell (fig. 8) 9t hours after the operation. And 
here I may mention that 1 have not found the muscular fibre- 
cells by any means a very perishable tissue. After an iris 
has been soaking two or three days in water, the muscular 
tissue of the sphincter is still quite recognisable, not only by 
the nuclei, but also by the individual fibre-cells. 

Of the figures above referred to, (7) and (8) are examples 
of the most elongated cells that I saw. By reference to the 
scale it will be found that the cell (7) is about 1-1 25th of an 
inch in length, and about 1-3 750th of an inch in greatest 
breadth ; while (8) is a little shorter, but of about the same 
average breadth. Kolliker divides muscular fibre-cells into 
three artificial divisions, according to their shape, of which 
the third contains the most elongated and most characteristic 
cells. Of this third division, the cells (7) and (8) are good 
examples, and, in fact, correspond in their measurements to 
average fibre-cells of the muscular coats of the intestines. 
The cells (9) and (10), though less characteristic in respect of 
their length — (9) being about l-333rd of an inch in length, and 
l-3000th of an inch in breadth, and (10) 1-oOOth of an inch by 
l-3000th of an inch, yet present the same peculiar delicate 
appearance and soft outline, and the same elongated nucleus, 
of not very high refractive power relatively to the contents of 
the cell, but clearly defined. All these cells have the same 
flat or ribbon-like form which is exhibited by the cell (8) at 
(a), where one edge has become turned up by a folding of the 
cell ; at (b) there seemed a tendency to transverse arrangement 
of the granules of this cell, which tendency is more strikingly 
exhibited at b and c in the cell (11), which, though not isolated, 
is introduced on that account. This tendency to transverse 
arrangement of the granules was long since noticed by Mr. 
Wharton Jones, as that gentleman has since informed me, 
and is, indeed, indicated in the drawings which are alluded 
to in the note above. In the cells of this iris, however, 
it was not by any means constant. Some of them, as (7) at 
(a), and (9) at (a) and (b), exhibited something of a longi- 
tudinal arrangement of the granules, such as was noticed some 



12 OBSERVATIONS ON THE 

years since in unstriped muscle by Mr, Bowman, who consi- 
dered the rows of granules as an approach to the fibrilla* of 
striped muscle. These cells are more granular than I have 
found those of the iris of the horse to be ; but I may here 
mention that, on comparing with these drawings the outline 
^f a fine specimen of a muscular fibre-cell of the sphincter 
pupilla' of this animal, which I had sketched by the camera 
lucida, I find it to be almost an exact counterpart of the cell 
(7) as regards the shape and size of both the cell and its 
nucleus. The nuclei of these cells measure from l-1400th to 
1-lllOth of an inch in length, and about l-9500th of an inch 
in breadth. They are not, however, the most characteristic 
that are to be found in the iris. Fig. 12 is from a camera 
lucida sketch of a nucleus of the sphincter pupillae of a horse ; 
it measures l-840th by 1-15, 200th of an inch, and exhibits in 
a very m^arked manner the true rod-shaped figure which ap- 
pears peculiar to muscular fibre-cells. On the other hand, I 
found some instances in the human iris of fibre-cells with con- 
siderably broader nuclei than those in the figures. The iris 
that yielded these cells was a blue one, apparently perfectly 
healthy ; it was active and brilliant before the operation, which 
was performed on account of central opacity of the cornea, 
resulting from an attack of a severe form of ophthalmia fifteen 
months previously. I watched the case closely from the first, 
and there was no reason to suspect implication of the iris in 
the inflammation. 

Having thus satisfactorily verified the fact of the existence 
in the iris of tissue identical with ordinary unstriped muscle, 
I was naturally led to inquire into its distribution in the 
organ : and, as this is a subject of great interest, and one 
about which much difference of opinion has prevailed, I may 
mention here the facts which I have hitherto observed, al- 
though there be not very much of actual novelty in them. 

Kolliker, in the article above referred to (loc. cit. pp. 53 and 
54), describes a sphincter and dilator pupillae, the former 
" very readily seen in the white rabbit, or the blue iris of man, 
from which the uvea has been removed, about a quarter of a 
line broad in man, exactly forming the pupillary margin, and 
situated somewhat nearer the posterior surface of the iris." 
Of the dilator he says, while confessing the difficulty of the 
investigation, that he believes it to consist of many narrow 
bundles, which run inwards separately between the vessels, 
and are inserted into tlio border of the sphincter. 

Bowman, on the other hand, states (op. cit. p. 48) that, 
whiU; in some instances a delicate narrow band of circular 
fibres exists at tlu; very verge of the pupil, yet, in the majority 



CONTRACTILE TISSUE OF THE IRIS. 13 

of instances, be feels sure that no such constrictor fibres of the 
pupil exist. He ascribes the contraction of the pupil to the 
inner part of the radiating fibres, which, he says, are joined 
and knotted in a plexiform manner round the pupil. It is 
scarcely needful to observe that such a statement from such an 
authority could not but go far to impugn Professor Kolliker's 
assertion respecting the existence of a sphincter pupilla\ 

My experience, I must confess, accords with that of Kol- 
liker, viz. that the sphincter is readily seen, while the dilator 
is that whose investigation alone presents very serious diffi- 
culty. In the first iris that I examined with a view to the 
distribution of the muscular tissue, I was struck, after remov- 
ing the usual pigment, with the appearance of a band on the 
posterior surface of the iris, near the pupil and parallel to its 
margin, quite evident to the naked eye, elastic and highly 
extensible. This proved to be the thickest part of the 
sphincter pupillae. I have examined six human irides with 
reference to the distribution of the muscular tissue, but in 
none have I had any difficulty in recognising the sphincter, 
which I have also found equally distinct in some of the lower 
animals, viz. in the rabbit, the guinea-pig, and the horse. In 
man I find it about l-30th of an inch in width, thickest towards 
its outer part, where it lies nearer the posterior surface of the 
iris than the anterior, and tliinning off towards the pupil, 
where it forms a sharp margin, covered apparently on its 
anterior aspect only by some vessels and nervous threads and 
a delicate epitheliated membrane, which is thrown into beauti- 
ful folds when the pupil is contracted. The fibres of the 
sphincter are not absolutely parallel, and this deviation is 
probably produced in part by the dilating fasciculi sweeping 
in at various parts in a curved manner, and becoming blended 
with the sphincter. The reason for this supposition will 
appear hereafter. By teasing out under the microscope a 
portion of the actual pupillary margin, I found the sphincter 
to consist at this part of apparently unmixed muscular fibre- 
cells, without any connecting cellular tissue. Fig. 13 is a camera 
lucida outline of the edge of a portion of the sphincter so pre- 
pared, which edge is seen to be formed of projecting fibre cells, 
and similar appearances may be seen with great readiness under 
a high power, after stroking the pupillary margin with the point 
of a needle. Indeed, the great facility with which the tissue 
may be thus broken up appears opposed to the idea of the 
fibre-cells being united end to end into fibres, as the descrip- 
tions formerly given of unstriped muscle would lead one to 
suppose. The ends appear to separate as readily as the edges 
and surfaces, and it would rather seem as if the fibre-cells of 



14 OBSERVATIONS ON THE 

a fasciculus wore placed with their long axis in one direction, 
cohering generally to one another, but without the formation 
of longer fibres than each cell itself constitutes. I may here 
mention incidentally that in the circular coat of the aorta of 
the sheep, where the muscular tissue is disposed in thin 
layers among the elastic tissue, I have observed a distinctly 
alternate arrangement of the fibre-cells without any formation 
of fibres, Mr. Wharton Jones's drawing of alternately dis- 
posed fibre-cells in the small intestine has been alluded to 
in the note above. A portion of the outer and thicker part 
of the human sphincter pupillae proved also extremely rich 
in muscular fibre-cells. In the rabbit and guinea-pig the 
sphincter has much the same appearance as in man, whereas 
in the horse it forms a wide but very flat band. 

Tlie dilating fibres of the iris present a very difficult sub- 
ject of investigation. 

And here I must express my belief — a belief the result of 
repeated and very careful observations — that the fibres de- 
scribed by Mr. Bowman as probably the contractile fibres of 
the iris are in reality the outer cellular coats of the vessels. 
The outer coat is very abundant in the vessels of the iris, and 
indeed even in the blue eye towaixls the sphincter quite ob- 
scures the bore of many of the vessels, and prevents the recog- 
nition of their vascular character, which can only be deter- 
mined by tracing them to their more external and more 
obviously vascular trunks. The distribution of these vessels, 
radiating between the sphincter and the circumference of the 
iris, and forming in the region of the sphincter a close and 
knotted plexus, corresponds accurately with Mr. Bowman's 
description of the distribution of the fibres of the iris. His 
account of the tissue of these fibres, which he considers as 
probably contractile, harmonises with the characters of the 
cellular tissue that clothes the vessels. This is peculiar ; con- 
sisting of very soft-looking fibres, whose fasciculi often require 
the best aid of a first-rate glass to resolve them into their 
constituent elements ; destitute apparently of yellow elastic 
fibres, as in the case of the cellular tissue of the uterus, but, 
like this, containing abundance of free nuclei, of roundish or 
elongated form. The fibres are completely gelatinised by 
acetic acid. Now such a tissue can hardly, in the present 
state of our knowledge, be regarded as contractile ; at any rate, 
if we can find any ordinary muscular tissue to account for the 
dilating action. On t<!asing out portions of the outer part of 
tlie human iris, 1 iiave found long delicate fasciculi, whose 
faint outline, absence of fibrous character, and possession of 
well-marked elongated nuclei parallel to the direction of the 



CONTRACTILE TISSUE OF THE IRIS. 15 

fasciculus, left no doubt in my mind that they were plain 
muscular tissue. 

So far my observations regarding the dilator agree with 
Kolliker's, but whether or not these fasciculi are connected 
with the cellular coat of the vessels I have hitherto been 
unable to determine. 

Among the lower animals the albino rabbit and guinea-pig 
appeared but little suited for the elucidation of this point. 
I have been most successful with the eyes of a horse, where, 
from the thickness of the iris and the abundance of pigment (for 
tlie eyes were black ones), I anticipated but little result from my 
examination. Having removed the uveal pigment from behind, 
I found that I was also able to strip off from the anterior sur- 
face a tough membrane, a portion of which, put under the 
microscope, appeared to be made up of peculiar short felt-like 
fibres, which were gelatinised by acetic acid. At and near 
the pupillary margin this membrane comes off in a continu- 
ous layer, leaving a delicate reticular structure, which contains 
the muscular tissue. It also contains vessels, as I proved by 
injection, and a black network, which consists of fine fibres, 
yellow, and highly refracting, more or less encrusted with pig- 
ment. I am uncertain whether or not this be a network of 
divided nerve-tubes with adhering pigment ; in some spots 
the pigmental crust was absent from a considerable length of 
the fibres. The sphincter pupillae is beautifully seen as a 
broad flat band, of extremely well-marked, unmixed, muscular 
fibre-cells ; but crossing this at right angles are found, here 
and there, other flat bands of fibre-cells, which are in so thin 
a layer that without isolation the width of the individual cells 
cannot be seen, and they are evidently of similar dimensions 
to those of the sphincter. On addition of acetic acid their nuclei 
are also seen to be exactly like those of the sphincter. These 
bands divide in their course towards the pupil into several 
fasciculi, some of which cross over the sphincter at right angles 
till very near to its pupillary margin, and then seem to blend 
with the sphincter by making a slight curve. Most of the 
fasciculi, however, arch away earlier from their first course 
and join the sphincter in more or less oblique lines. The 
bands from which these fasciculi diverge may be traced aAvay 
from the pupil for some distance, continuing their course at 
right angles to the sphincter till they are obscured by other 
tissues. Hence I think the inference may fairly he drawn that 
these are the insertions of the dilating muscular bundles. In 
the horse, then, the dilating fasciculi appear to consist of pre- 
cisely the same tissue as the sphincter, and to blend with it 
in their insertion. The flat bands of muscular tissue above 



16 CONTRACTILE TISSUE OF THE IPJS. 

spoken of seemed to have no special relation to the vessels, 
some of which were filled with injection. In the outer part 
of the iris of the same horse I found a delicate muscular fasci- 
culus lying near but not intimately connected with one of the 
radiating- vessels of this part. In the human iris I have seen 
a muscular fasciculus, as it appeared from the nuclei it con- 
tained, crossing the sphincter at right angles for a short dis- 
tance ; this observation, so far as it goes, seems to imply that 
the same mode of insertion of the dilator occurs in man as 
in the horse. 

The fibre-cells of the dilator appear to be held together 
much more closely than those of the sphincter, at least in the 
outer part of the iris ; for I have never been able to define the 
individual fibre-cells in a perfectly satisfactory manner in the 
dilator, though I have often teased out portions of the outer part 
of the iris. The dilating muscular tissue is also probably less 
abundant than the muscular tissue of the sphincter ; and this, 
if the fact, will help to account for the comparative difficulty 
in discovering it, I may here mention that both in the cat and 
in the rabbit, soon after death, dilatation of the pupils being 
present, exposure of one iris to the air caused it to contract 
at once, while the pupil continued dilated in the other eye, 
which was untouched, I do not know if this fact has been 
observed before, but it is interesting in two ways — first, as 
showing that the muscular tissue of the iris, like other mus- 
cular tissue, is obedient to the stimulus of exposure ; and, 
second, as proving either that the sphincter is in these animals 
a decidedly more powerful muscle than the dilator, which is 
equally exposed to the stimulus ; or else that the fibres of these 
two muscles have different endowments, as has been shown by 
Mr. Wharton Jones to be the case with the muscular tissue of 
the arteries and veins of the bat's wing ; where, although the 
veins' are muscular, and even contract rhythmically, yet the 
y *» arteries alone exhibit tonic contraction when irritated by me- 
chanical stimulus. 

A- ric4i! network of extremely fine fibres, seen readily in the 
blue human iris^igwed from tlie anterior aspect, appears to 
represent the nerves of the organ. The fibres are of a yellowish 
colour, and are possessed of pretty high refractive power ; they 
present, if really nervous, a good illustration of the division 
and anastomosis of ultimate nerve-fibres ; the smallest divi- 
sions visible under a high power are seen only as fine lines, 

I have not seen any nerves in the human iris presenting the 
double (ontour ; but in the Iris of a cat, so fresh that the tissue 
<-ontracted under the needles as I teased it out, the double 
contour of the nervc-tulies was already very strongly marked, 



OBJECTS FOR MICROSCOPICAL EXAMINATION. 1 7 

showing the existence in this animal of the white substance 
of Schwann in these nerves. The double contour surrounded 
the ends of the nerve-fibres which I supposed to have been 
broken by the teasing process. This last fact seemed to con- 
firm the general belief that the double contour is a post- 
mortem effect, which, however, was in this instance a very 
rapid one. 

I believe that a further investigation of the fresh blue iris 
in man, and of the horse's iris, would supply the means of 
finally settling the question of the distribution of the dilator 
pupillae. 

My engagements do not allow me to carry the inquiry fur- 
ther at present ; and my apology for offering the results of an 
incomplete investigation is, that a contribution tending, in 
however small a degree, to extend our acquaintance with so 
important an organ as the eye, or to verify observations that 
may be thought doubtful, may probably be of interest to the 
physiologist. 



Hints on the Subject of collecting Objects for Microscopical 
Examination. By George Shadbolt, Esq. 

Having procured a good microscope, it is often a source of per- 
plexity to the novice to obtain a sufficient supply of objects on 
which to exercise its powers, although the real difficulty consists 
not in procuring enough, but in finding time to examine with 
proper care all that is readily obtainable. It must be admitted 
that the acquisitive powers, like all others, are materially im- 
proved by being exercised, and many good collectors in embryo 
remain undeveloped from the want of a little information to 
commence upon. The object 1 have in view is to offer a few 
hints to those who may happen to be deficient in this funda- 
mental knowledge, especially as regards the means of finding 
Diatomaceae, Desmidiea*, and other Algae. Masses of water 
in all situations are generally to be examined for objects of this 
class. 

Rivers, brooks, springs, fountains, ponds, marshes, bogs, 
and rocks by the sea side, are all localities that may be 
expected to be productive, some being more prolific than 
others, and the species obtained differing of coui'se in general, 
to a certain extent, according to the liabitat. 

On considering the nature of some of tlie places inditated 
it will of course be apparent that in order to spend a day in 

VOL. I. c 



18 HINTS ON COLLECTING OBJECTS FOR 

collecting with any comfort, it will be necessary to make some 
provision for keeping; the feet dry, for which purpose a pair of 
India rubber goloshes Avill answer, or better still a pair of 
waterproof fishing boots, but without one or other the work is- 
by no means pleasant. 

A dozen or two of small bottles made of glass tubing about 
half an inch in diameter and without necks, and from one to 
two inches in length, are the most convenient depositories for 
the specimens if intended ultimately for mounting ; and it is 
advisable also to take two or three wide-mouthed bottles of a 
larger size, holding from one to two fluid ounces, an old iron 
spoon, a tin box, some pieces of linen or calico two or three 
inclies square, a piece of string, a slip or two of glass with the 
edges ground, such as are used for mounting objects, and, 
lastly, a good and pretty powerful hand magnifier. Two Cod- 
dington lenses mounted in one frame of about half an inch and 
one-tenth of an inch in focal power are specially convenient. 

Perhaps it will be as well in pointing out a few localities 
to describe some that I have actually visited, with the means 
of access, and the appearance of the various species en masse 
that I have met with. 

Swanscombe Salt Marsh will be found well worth a visit, and 
it can be reached either by steamboat or railway from London 
Bridge to Northfleet. On quitting the railway station make 
towards the almshouses on the top of the hill, and arriving 
at the road turn to the left, descend the hill and cross a sort 
of bridge over a somewhat insignificant stream. Continue 
along the main road a little further until a point where it 
begins to ascend again, and diverges to the left towards the 
railway, here quit it, taking your course along an obscure 
road nearly in a direct line with the main one, passing 
a windmill on the right hand, and continuing until you arrive 
at another still more obscure road turning off to the right, 
which road appears as if made of the mud dredged from the 
bottom of the river and partially hardened. This is Swans- 
comlje Salt Marsh, and the road just described leads towards 
Broad Ness beacon. On either side is a sort of ditch, one 
containing salt or very brackish water, the otlier filled with a 
sort of black mud, about the consistence of cream, the surface 
being in parts of a slaty grey with little patches here and 
there of a most brilliant hroion colour glistening in the sun- 
shine, and presenting a striking contrast to the more sombre 
shade. By carefully insinuating the end of one of tlie slips 
of glass under this brilliant brown substance and raising it 
gently, it can bo examined with the Coddington, and it will 
probably be found to c<»nsist of myriads of specimens of 



MICROSCOPICAL EXAMINATION. K» 

Pleurosigma {Navicula of Ehrenberg) angulatum, or Balti- 
cum, or some other species of this genus. The iron spoon 
now is useful, as by its aid the brown stratum, with little or 
no mud, can be skimmed off and bottled for future examina- 
tion. On the surface of the water in the other ditch may be 
noticed a floating mass of a dark olive colour, which to the 
touch feels not unlike a lump of the curd of milk, and consists 
of Cyclotella Menigldniana and a Surirella or two embedded 
in a mass of Spirulina Hutchinsia, and another mass of floating 
weed which feels harsh to the touch, proceeding from a quantity 
of a Synedra, closely investing a filamentous alga, and else- 
where Meloseira nummuloides ( Gallionella of Ehrenberg). 

In a trench by the sea-tcall, as it is termed, is a mass of brown 
matter of a shade somewhat different to any hitherto observed, 
adhering to some of the parts of the trench, being partially sub- 
merged, and having a somewhat tremulous motion on agitating 
the water. This is a species of Schizonema, and it consists of 
a quantity of gelatinous hollow filaments filled with an im- 
mense number of bright brown shuttle-shaped bodies, like 
very minute Naviculce. It is not necessary to be particular 
about collecting the specimen free from mud, as the filaments 
are so tough that the mud can be readily washed away by 
shaking the whole violently in a bottle of water and pouring 
off the mud without at all injuring the specimen. The Am- 
phisporium alatum communicates a somewhat frothy appearance 
to the otherwise clear water, and to get any quantity of this 
requires a little management, but by skimming the surface 
with the spoon, and using one of the larger bottles, an abund- 
ance may readily be obtained. 

Between the sea-wall and the river the marsh is intersected 
in every direction with a number of meandering creeks, being 
in some places eight to ten feet deep, though in others quite 
shallow, but it is exceedingly difficult to make one's way 
amongst them, and I have never found them so prolific any- 
where, on the few occasions of my visiting the place, as in the 
parts more away from the influence of the tide. It will be olj- 
served, from what I have stated, that the brilliant brown colour — 
of a deep but bright cinnamon tint — is one of the best indica- 
tions of the presence of Diatomacece ; and, though this is by no 
means universal, the variation is most frequently dependent 
upon the presence of something which qualifies the tint. The 
peculiarity of the colour is due to the endochrome contained in 
the frustule, and this must be in general got rid of before the 
beautiful and delicate markings can be made out ; but it is 
highly advantageous and instiuctive to view them in a living 
state, and this should be done as soon as possible after reaching- 

c 2 



20 HINTS ON COLLECTING OBJECTS FOR 

home with all specimens procured from salt-water localities, 
as they rapidly putrefy in confinement, and emit a most dis- 
gusting odour, not unlike that arising from a box of inferior 
Congreve matches. 

Washino- in fresh water, and then immersing in creosote 
water, preserves many of the species in a very natural-looking 
manner ; but they are killed by the fresh water, and the en- 
dochrome becomes much condensed, in the Pleiirosigmata and 
some other species. The addition of spirit quite spoils the 
appearance of the frustules, as it dissolves the endochrome. 

There is another salt marsh a little farther down the same line 
of railway at Higliam, which it would be well to explore ; but 
as I have only paid it one visit, at the most unfavourable time 
of the year I could possibly have hit upon — the early part of 
December, I did not find many species there. I would observe 
that, as far as my limited experience extends, the most favour- 
able months for procuring Diatomaceae are April, May, Sep- 
tember, and October, but some species are found in perfection 
as early as February, and many as late as November, and a 
few at all times of the year. 

There is a piece of boggy ground near Keston, beyond 
Bromley in Kent, where the river Ravensbourne takes its rise, 
where many interesting species of Desmidieae and other fresh- 
water alga? may be procured.* From Bromley walk on 
towards Keston, passing near Hayes Common and Bromley 
Common on the right. Continue for about another half mile 
along the road, and then turn to the right hand, pass the reser- 
voirs, and approach an open space where there is a bog of 
about a quarter of a mile in extent, and, tending towards the 
right, make your way amcmgst heaths, ferns, mosses, and the 
Ijeautiful Drosera rotundifolia (sundew), to the lower part 
of the little stream rippling through a sort of narrow trench in 
the Sphagnum, iScc. By working your way up the stream 
you avoid the inconvenience, which would otherwise be expe- 
rienced, of the water being rendered turbid in consequence of 
having to tread in the boggy ground. 

In the centre of the little stream may be observed something 
of a pale pea-green colour flickering about in the current, 
which, on your attempting to grasp, most likely eludes you, and 
slips through the fingers, from being of a gelatinous nature. It 
consists of a hyaline substance, with a comparatively small quan- 
tity of a l)right green endochrome disposed in little branches, 
and this is tlie Drapariialdin (jlomerata. Anothc object is a 

* An omnibus leaves the Elephant and Castle at ha'f-past nine every 
morning for Hromley, whicli is the most convenient means of access to the 
spot. 



MICROSCOPICAL EXAMINATION. 21 

mass »>f green filaments, rather harsh to the touch, very slip- 
pery ; when viewed with a lens of moderate power each filament 
is seen to be surrounded with several bands of green dots, look- 
ing like a ribbon twisted spirally, and may be recognised as 
Zi/gnema nitidum. In various parts there are other species of 
Zyrpiema, Tyndaridea, 3Ioii(/eotia, Afesocaj^pus. a.nd many others. 
Keeping up the stream, and occasionally diverging a little 
on either side of it amongst the miniature bays and pools 
in the Sphagnum, on looking straight down into the water 
we shall probably see at the bottom a little mass oi jelly, of a 
bright green, and studded with numerous brilliant bubbles of 
oxygen gas. This is the general appearance of most of the 
Desmidieae, as Micraderias, Euastrum, Closterium, Cosma- 
rium. Sic. 6cc. The spoon is also a handy tool in this case, 
though by practice the finger will do nearly as well, the chief 
difficulty arising when the specimen is brought to the surface 
of the water, it not being easy to get it out in either case with- 
out losing a considerable portion of it. 

Little pools in the bog, made by the footsteps of cattle, are 
particularly good spots to find Desmidieae, and I have fre- 
quently found manv species in a very contracted space. 

The most prolific bog I am acquainted with is at Tunbridge 
Wells, near a house known as Fisher's Castle, not far from 
Hurst Wood. There is also a good one at Esher, at a spot 
called West End. 

It must not be imagined that nothing can be obtained in 
this department of botany without going some distance from 
town, but assuredly only commoner and fewer species can be 
met with nearer home. At the West India Docks I have 
found Synedra fasciculata, Goniphonerna curvatum, Diatoma 
elongatum, Diatoma vulgare, Surirella ovata, 6ic. <Scc. ; and, by 
the way, at this same place a few objects not of the botanical 
class, as Spongilla Jiuviatilis, Cordylophora lacustris, Alcyn- 
nella stagnorum, &c., are obtainable in abundance in the 
autumn. 

In the Serpentine may be found Cladophora ghmerata and 
Sphceroplea crispa, two of the filamentous algae ; and in the 
ornamental water in St. James's Park, Cocconema lanceotatum, 
and other species of this genus, Gompkonema cristatum, 
&c. &c. Epping Forest, about the neighbourhood of Leyton- 
stone, Snaresbrook, Wanstead, and Woodford Bridge, are also 
capital localities for the filamentous Algae, especially the last 
named, where Nitella transluceiis and Chara vvlgai is abound. 

In the fountains in the Surrey Zoological Gardens I have 
met with several species of Diatomacea* and Desmidieae at dif- 
ferent seasons, including the genera of Synedra, Gompkonema, 



21 OBJECTS FOR MICROSCOPICAL EXAMINATION. 

Cocconeis, Stauroneis. Cijmatopleura, Surirella, Pleurosigma, 
&c., among the former, and Closterium, Cosmarium, and 
Staurasfriun among- the latter. 

Hampstead Heath, although producing some of the above, 
is a place far more prolific in aquatic animalcules, even if we 
exclude the Volvox globator from this latter class, and reckon 
it as belongrinsr to the vegetable kingdom. 



Observations on the existence of Cellulose in the Tunic of 
Ascidians. Bj T. H. Huxlev, Esq., F.R.S, 

A CAREFUL examination of a number of species of the Ascidian 
genera Boltenia, Cynthia^ Molgula, Pliallusia, Stjntethys, Apli- 
dinm, Pyrosoma, and Salpa — including, therefore, every mo- 
dification of the type, has led me to the following conclusions 
with regard to the structure of the mantle. The investigation 
was made with a full knowledge of what had been done by 
Lowig and Kolliker and by Schacht (p. 34), and I have only 
ventured to differ from them upon strong evidence. 

1. In the most gelatinous forms of the test, as in Syntethys 
and Salpa, it consists of a soft homogeneous or delicately 
striated basis, through which round nucleated cells (nuclei of 
Kolliker and Lowig) are scattered. These cells present no 
ramifications, and the presence of cellulose is demonstrated 
with very considerable clifficulty. When the iodine solution is 
added the whole mass becomes coloured yellowish-brown, the 
nucleated cells taking rather a deeper tint than the rest. Tlie 
addition of sulphuric acid slightly contracts the whole sub- 
stance, and if used with care gives the edges the characteristic 
blue tinge. The cellulose is evidently diffused through the 
intercellular nitrogenous basis ; for the first evidence of the 
operation of the sulphuric acid is seen in a slight diffused, even 
green shade, which is produced by the incipient blue re-action 
of the cellulose mingling with the existing yellovv-l^rown colour. 
As the action of the test goes «)n, the edges of tlie membrane 
l)pc()me deep l)lue, while the green tinge passes insensibly into 
the blu'e on the one side and into the yellow on the other. 

As Schacht justly points out then, the substance of the test 
is not pure cellulose but cellulose deposited in a nitrogenous 
meml.)ranc. It exists in the same condition as the calcareous 
salts in l)one, or as the chondrin in cartilage. 

Substituting cellulose for calcareous salts, the structure of 
the t<'st of Sa/j/a is exactly that of the bono of plagiostomous 
fishes (Lcvdig, Beitriige zur Anat, d. liochen. I laie, l'Sr)2). 



HUXLEY ON CELLULOSE IN THE TUNIC OF ASCIDIANS. 23 

2. Ft/rosoma has a firmer test, which contains far more 
cellulose. This is more readily detected by the iodine and 
sulphuric acid, but in its relation to a general nitrogenous 
basis precisely resembles that of Scilpa. 

The nucleated cells differ from those of Salpa in being 
thrown into very long processes which meet and unite — just 
like those of Volvox as described by Mr. Busk. On the other 
hand they assume exactly the appearance of bone corpuscles — 
though the processes are generally straighter and are rarely 
branched. 

Making the same substitution as before, we have in the test 
of Pyrosoma a structure comparable to that of the lamina 
papyracea of the ethmoid bone. 

'6. In the Phalhisice there is an indistinctly fibrillated basis, 
containing a large amount of cellulose in all essential respects 
resembling the foregoing. Nucleated cells, provided with 
irregular processes, are scattei'ed through this substance. 

The large cells described by Lowig and Kolliker and by 
Schacht are not cells at all but are vacuolae — very probably 
produced, like the cancelli of ordinary bone, by interstitial 
absorption. There is no lining membrane like that described 
by Schacht. With care the walls may be coloured deep blue 
to their very edges. The appearance of fibres is produced by 
the striation which runs through the whole mass, and is 
especially distinct upon the walls of the cavities. It exists 
after the action both of sulphuric acid and of caustic soda. 

Lastly, the resemblance to perfect bone is completed by the 
canals which are hollowed out in the substance of the test for 
the vessels (or rather prolongations of the outer tunic, which 
is Avhat they really are J. In the walls of these canals I have 
frequently seen the nucleated cells projecting just as Kolliker 
describes them in the " medullary canals " of developing bone 
(Mikroskopische Anatomic, p. 369). 

The spiral fibres described by Schacht are the muscular 
fibres surrounding the wider portions of the vessel-like pro- 
longations. 

Finally, with regard to the relations of the cells to the cellu- 
lose — anatomically and physiologically — I do not see any force 
in the distinction attempted to be established by Schacht 
between animals and plants. The nucleated cell of the As- 
cidian tunic answers exactly to the primordial substance of' the 
plant. The cellulose is deposited outside both. The amount 
of nitrogenous matter mixed up with the cellulose deposit 
appears to l)e a mere question of degree — and the nature 
and existence of an inUncellular substance in the vegetable 



24 HUXLEY OX CELLULOSE IX THE TUNIC OF ASCIDIANS. 

kingdom are still matters too much disputed to be good grounds 
of distinction. 

Tlie physiological theory of Lowig and Kolliker, that the 
cellulose of the Ascidians is derived from the Diatomaceae 
upon which they feed — is incompatible with the fact (Annals 
of Xat. Hist , Aug., 1852) that the larval Ascidian contains 
cellulose before any of its organs are developed. 

To examine the test of an Ascidian for cellulose, I find the 
best way to be, to take a very thin section and moisten it with 
a strong solution of iodine in iodide of potassium. After being 
thoroughly impregnated with the iodine, the superfluous fluid 
should be drained off, and the segment carefully blotted with the 
finger [or hair pencil]. A handkerchief or blotting-paper may 
readily give rise to error bv leaving behind small fragments of 
vegetable fibre. A drop of sulphuric acid, as strong as can be 
procured, should now be added. If much cellulose is present a 
deep blue colour will appear immediately, beginning at the edges 
of the slice ; if there be but little, the colour will not appear for 
some time. The application of the test requires some care ; 
and while its success is most valuable evidence of the presence 
of cellulose, its failure is not by any means negatively con- 
clusive, unless the experiment has been frequently and care- 
fully repeated. 



( 25 ) 
TRANSLATIONS. 



Description of Actinophrys Sol. By A. Kolliker. From 
Siebold and Kolliker's Zeitsch., 1. p. 1^8. 1849. 

The simplest forms in animated nature are to the genuine 
naturalist of great value and significance. Though wanting 
in the attractions derived from multiplicity of shapes, and 
although the investigation of their life is appai'ently without 
any immediate purpose of utility, yet do they hold out to the 
true philosophic inquirer an ample reward, and, from the 
paucity of means exhibited in them for the production of great 
effects, they are well calculated to charm and interest the mind. 
The solution in fact of general questions of the utmost im- 
portance depends upon a correct knowledge of the lowest 
organisms — such questions, for instance, as — What is an 
animal ? What a plant ? What an organism ? or even, What is 
life itself ? And when it is considered that these lowest 
forms are in great measure to be regarded as simple cells, an 
unprejudiced inquiry into the vital phenomena presented in 
them, becomes of daily greater importance towards a proper 
comprehension of the higher organisms, which are also in great 
part composed of cells. 

Induced by these considerations, the author has pursued the 
investigation of certain of the lower forms of animal life. 
Some of the fruits of his labours have already appeared in a 
paper on the Gregarinae, &c., and he now presents the follow- 
ing account of the Sun Animalcule — Actinophrys Sol. 

I. Anatomy of Actinophrys Sol. — The form of the Actino- 
phrys (figs. 1, 2, 3) is that of a depressed sphere ; viewed on the 
flat sides, it is perfectly circular, and on the edge, elliptical. The 
surface of the body is universally and pretty closely beset with 
delicate tentacular filaments. The length of these filaments is 
at least equal to, or much greater than, the longer diameter of 
the animalcule ; they arise from a rather wide base, and be- 
coming gradually attenuated, though with frequent nodosities, 
terminate in an extremely fine almost invisible point. 

The colour of the animalcule, independent of all foreign 
contents, is, to the naked eye, a dull white ; when more 
closely examined, the interior usually appears whiter than, 
:md to be rather sharply defined from, the transparent external 
j)urtion ; and this is confirmed upon microscopic inspection. 

Measurements : the smallest individual tliat came under 
the author's inspection measured l-38th — l-30th"'; the largest 



•26 KOLLIKER ON ACTINOPHRYS SOL. 

l_(3tli — l-4th" ; the metlium size was l-8th — l-6th'" ; the 
filaments l-6th— l-3rd'", or even i"' lon<?, and 0-0016— 
0006 " wide at the basis ; the little nodosities upon them 
0-007'' long:, and • 004" 'wide. 

The structure of Actinophrys has not hitherto been correctly 
understood by the greater number of observers. According to 
Ehrenberg (' Infusor.,' p. 303), it possesses a mouth with a pro- 
boscis and an anus, which are opposite to each other, and in 
the interior, numerous stomachs, on which account it is referred 
to the division Enantiotreta of the Enterodela or Polygastrica 
having an intestine. Tlie older observers also, such as O. F. 
Miiller and Eichhorn, are, to some extent, of the same opinion, 
as well as most modern zoologists, who simply adopt the 
statements of Ehrenberg. But Dujardin (' Infusoires,' p. 259) 
characterises Actinophrys as ' animaux sans organisation 
appreciable ;' adding, in explanation (p. 260), that their body 
consists of a soft grumous substance, in which nothing can be 
observed but variously sized granules, and frequently very large 
vacuolae. According to the author's investigations, Dujardin, 
in this instance, as in many others in which he has combated 
the views of Ehrenberg, is altogether in the right ; for, although 
he was not acquainted with the vital phenomena of Actinophrys, 
lie comes very near the truth in what he has observed of its 
structure. 

Actinophrys, in fact, does not present a trace of moutlj, 
stomach, intestine, and anus, consisting entirely of a perfectly 
homogeneous substance, of very soft and delicate consistence. 
Examined under a higher magnifying power (Plate I. figs. 1, "2, 
3) the whole animalcule at first sight seems to be composed of 
the most regular and delicate tissue of round or polygonal cells ; 
but on closer inspection it will soon be found that, in the usual 
sense? of the term, there are not in reality any cells. On the 
contrary, it will be seen that what appears as a cell-memljrane 
is not any special envelope, but that it is in continuous con- 
nexion with a pale substance, which in greater or less quantity 
occupies, like a sort of intercellular substance, the space 
between the supposed cellular cavities ; and also that the 
numerous opaque granules are retained in this substance, and 
in no case contained in the cavities, which are filled merely 
witli a clear aqueous (luid (figs. 1, 4). 

When the animalcule is torn or crushed it becomes evident 
that it is entirely composed simply of a homogeneous substance 
with vacuoles, for it will be found that the supposed cells may, 
at j)l('asurc, under pressure^ be made either to coalesce into 
larger or be divided into smaller cavities, presenting in all 
n-spects the character of the normal ones. The; only thing 



KOLLIKER ON ACTINOPHRYS SOL. 27 

indicating the existence of cells is this, that in the innermost 
portions of the animal after it has been crushed, a few vesi- 
cular particles come into view, which, owing to the pre- 
sence of an internal corpusule, more resemble cells. Under 
pressure these vesicular bodies may be readily isolated, they 
then behave sometimes as cells with nucleus and nucleolus, 
sometimes as free nuclei. The author is in fact inclined to 
regard them as cells and nuclei, lying in some of the interior 
vacuoles, for such, and such only, are the vesicular spaces in 
which they are inclosed, and will say more about their nature 
subsequently. 

Disregarding, then, these adventitious elements of secondary 
importance, the entire Actinoplirys is throughout composed of 
a simple homogeneous substance, with granules and vacuoles. 
In it may more or less clearly be distinguished two portions, 
a cortical and a nuclear. The former (figs. 1, 2, 3, a) is, on 
the average, l-36th"' thick, surrounds the nucleus, supports 
the tentacular filaments, and is more transparent than the 
nuclear (figs. 1, 2, 3, b), which presents the appearance of a 
flattened sphere of more or less white colour. Both portions 
possess essentially the same structure, and the difference between 
them depends upon the circumstance that, in the substance of 
the nucleus, there are many more granules than in the cortical 
portion. These granules are rounded, opaque, ver}' minute 
(at most 0005 '' or 0" 001"), insoluble in acids or alkalis, and 
therefore probably of a fatty nature. The homogeneous sub- 
stance of the body (figs. 1, 2, 3, 4, c), of a yellowish tint, is 
very soft, but highly elastic, so that an Actinophrj/s placed on 
a plate of glass in too small a quantity of water, becomes flat- 
tened out into a large and extremely thin disc, which, upon 
the addition of water, reassumes its original globular form ; it 
is rendered pale by acetic acid and cold potass, in which latter 
it gradually, but when heated, rapidly, dissolves, and it is 
therefore of a nitrogenous nature. The clear spaces or vacuoles 
(figs. 1, 2, 3, 4, rf) are of pretty uniform size, 009—0 02'", 
or in the mean 012'" in diameter. In the cortical portion 
they are disposed in two or three tolerably regular layers ; but 
in the nuclear part, and especially towards the centre, they 
exhibit no definite arrangement, and are at the same time 
smaller and have more interstitial substance than in the cortical 
portion, where there is frequently only a thin lamella between 
two vacuoles. The periplieral layer of this fundamental sub- 
stance is somewhat thicker, although still extremely thin, even 
where tlie tentacular filaments are given off from thicker parts 
of it. These filaments are in fact immediate prolongati(ms 
from it; they (figs. 1, 2, 3, 4, e) consist of the same sub- 



2 8 KOLLIKER ON ACTINOPHKYS SOL. 

stance as the rest of the body, from which they differ only 
in their never having vacuoles, and if granules, but very few of 
them. 

II. Physiology. — As regards the vegetative functions, the 
mode in which the Actiaophrys is nourished is of the highest 
and most special interest. Although the creature has neitlier 
mouth nor stomach, yet it takes in solid nutriment and rejects 
what is indigestible. This miracle, for so it may almost be 
called, is thus effected : the Actinophrys feeds upon infusoria 
of all kinds — minute crustaceans (Rotifera, minute species of 
Lynceus, the young of Cyclops, &c.), and the lower algae 
(Diatomaceae, spores of Vaucheria, Closterium, Sic). When, 
in 'its progress through the water, it approaches one of these 
little plants, or when an Infusorium has come into proximity 
with it, both plant and animal, as soon as they touch one of the 
tentacular filaments, usually adheres to it. Now as the fila- 
ment with its prey slowly shortens itself, and the latter ap- 
proaches the surface of the body, all the surrounding filaments 
apply themselves upon it, bending their points together so that 
the captive becomes gradually enclosed on all sides (fig. 2, J) ; 
according to all appearance these filaments also become more 
or less shortened. In this way the morsel is gradually brought 
to the surface of the body, the filament by which it was seized 
being finally so much shortened as to disappear altogether, and 
having, as not unfrequently happens, relinquished its hold 
upon the prey, after the latter has become encompassed by the 
surrounding filaments. These gradually apply themselves 
more and more closely togetlier around it, forcing it towards 
tlie surface of the body. 

The following proceeding now takes place : — The spot of 
the surface, upon which the captured animalcule is lying, 
slowly retracts and forms at first a shallow depression gradu- 
ally becoming deeper and deeper (fig. 2 J'), in which the 
prey, apparently adlierent to the surface and following it in 
its retraction, is finally lodged. The depression, by the con- 
tinued retraction of the sul:)stance, now becomes deeper ; the 
imprisoned animalcule, which, up to this time, had projected 
from the surface of the Actinophrys, disappears entirely within 
it ; and at the same time the tentacles, which had remained 
with their extremities applied to each other, again erect them- 
selves and stretch out as before (fig. 2 g). Finally, the de- 
pression a(quires a flask-like form by the drawing in of its 
margin (fig. 2 g), the edges of whicli coalesce, and tlius a 
cavity closed on all sides is formed, in which the prey is 
lodged. In this situation it remains for a longer or shorter 
time, gradually liowever approaching tlie central or nuclear 



KOLLTKER ON ACTINOPHRYS SOL. 29 

portion, and at last passing entirely into it in order to await 
its final destination. In die meanwhile the external portion 
of the Actinophr} s regains in all respects its pristine condition. 
The engulphed morsel is gradually digested and dissolved, as 
is readily seen by its change of appearance from time to time. 
If entirely soluble, as, for instance, an infusorium, the space in 
which it is contained contracts as the dissolution of its con- 
tents goes on, and finally disappears altogether ; should there 
be, however, an indigestible residue (a membrane composed of 
cellulose, a portion of chitine, a shell of a Lynceus, or case of 
a Rotifer, tScc), a passage for its exit is formed, and it is ex- 
pelled by renewed contractions of the homogeneous substance, 
and in the same direction or nearly so as that which the morsel 
followed in its introduction. The passage and the opening 
through which the expulsion was effected disappears again 
without leaving a trace. 

The above is a representation in general terms of the very 
curious mode in which the Actinojihrys receives, digests, and 
rejects what remains of its nourishment. The following ob- 
servations may serve to make it better understood. As regards 
the formation of the tentacular filaments it is stated by Ehren- 
berg, who at the same time assigns to them the duty of seizing 
the prey, that they exert a " rapidly fatal " influence upon the 
captured animalcule. This is incorrect. The author has very 
often seen infusoria which were adhering to the tentacles still 
in motion, and even when arrived near the surface of the body 
break away and escape ; and in several cases he has observed 
very lively movements in animalcules which had been com- 
pletely swallowed and imbedded in the cortical substance or 
in the nucleus. It would appear that the only action of the 
tentacles is to retain the prey by their adhesive surface, and 
probabW to involve it also with their extremely fine extremities, 
and then that, by their mutual approximation, they continue 
to hold it fast, and at the same time by their contraction bring 
it towards the surface of the body. 

In the second place, with respect to the non-existence of a 
mouth, stomach, and anus, no doubt whatever can be enter- 
tained. Without the slightest notion of the remarkable con- 
ditions he was about to find, the author approached the investi- 
gation oi Actiiwphrys with a due belief, at least, in the existence 
of the mouth and anus, described by Ehrenberg. When he 
for the first time witnessed the process of reception of a morsel, 
he thought in fact that he had found the mouth in the depres- 
sion formed on the external surface ; and in the w^hitish nucleus 
into which the morsel was finally lodged, a large central 
stomach. But he was soon undeceived, for, by longer observa- 



30 KOLLIKER ON ACTINOPHRYS SOL. 

tion of one and the same individual contained in a watcbglass 
he soon perceived that the supposed mouth disappeared again 
after the entrance of the morsel without leaving a vestige, 
whilst other observations showed him that the supposed 
stomach was a homogeneous substance, with similar cavi- 
ties, and of the same nature as the cortical. Now as he had 
also ascertained the merely transitory existence of the anus, 
and, by steadfast consideration for hours together of different 
individuals, had also made the discovery that the Actinoplirys 
employs the same part of the surface of its body at pleasure 
and temporarily as either mouth or anus — the mystery was 
cleared away, and views opened out which further investigation 
the more firmly established. 

In the reception and rejection of the morsel, the manifestly 
contractile homogeneous substance of the body appeared to 
play the principal part. By its retraction in any part a 
hollow is formed into which the morsel enters ; then the 
borders of the hollow approach and coalesce in consequence of 
contraction, and the morsel is within the body ; new con- 
tractions, lastly, propel it from without inwards towards the 
nucleus, and at a later period serve again to expel the undi- 
gested remains. All these contractions are partial, taking 
place only in one or few spots at the same time, whilst at 
other places the substance of the body remains passive, yielding 
before the advance of the morsel. How the clear spaces are 
concerned in the penetration, advance, and expulsion of the 
food, it is difficult to see ; they seem to disappear in places 
and to be reformed, though it cannot be altogether denied that 
they may merely separate from each other in order to make 
way for the entrance of the foreign body. It is especially 
to be remarked that the advance of the morsel into the body 
has the greatest resemblance with what is observed in uni- 
cellular infusoria, having a mouth, such as Bursaria, &c., when 
the morsel enters the soft contents of the cell, or the so-called 
parenchyma. 

The number, as well as the size of the morsels, taken at one 
time by the Actinophrys, is very various. Very frequently 
there may be 2, 4, 6, at the same time — frequently also more 
than 10 or 12. Ehrenberg counted as many as 16 stomachs, 
which may be looked upon as so many separate morsels. He 
also noticed the ingestion of indigo, which could not have 
gained admission in any other way than that by which the 
infusoria and other aliment enter. The largest morsels noticed 
by the author consisted of a Lynceus or a young Cyclops. 
Eichhorn indeed mentions even a water-flea (Z>a^/mea ?), about 
the size of which, however, no remark is made. 



KOLLIKEH ON ACTINOPHRYS SOL. 31 

The mode in which the nutrient morsel is digested is not 
clear. Every morsel, without exception, lies in a large vacuole, 
formed temporarily for its reception in a small quantity of 
clear fluid, of which it does not appear whether it comes from 
without, or is secreted in the interior of the animal and col- 
lected round the morsel. The food is digested in a few hours 
(2 — 6), and the indigested residue, together with the drop of 
fluid by which it is surrounded, is expelled. In this way the 
sharply defined drop, with the enclosed fa?ces, are pushed in 
an entire mass through the parenchyma of the body. Scarcely 
arrived at the surface, however, the mass breaks up and be- 
comes dispersed, although the solid particles which had been 
included not unfrequently remain for some time as a granular 
body with irregular outline, as a greyish cloud, in the neigh- 
bourhood of the animal, until it is at last ent,irely dissipated. 

Of the other vegetative phenomena there is not much to 
remark. Regarding the mode of growth, of the conditions 
attending which there is nothing to be seen, it might merely 
be remarked that individuals which have not eaten for some 
time present only a few granules in their parenchyma, and have 
a nuclear substance almost as transparent as the cortical ; 
whilst, on the other hand, those containing numerous morsels 
of food, and consequently which are evidently better nourished, 
invariably present numerous granules. Hence it might with 
tolerable certainty be concluded that these (fat) granules are 
formed from the food, and during fasting are re-absorbed ; 
probably, in general, they are constantly formed and removed 
as must in some degree be assumed to be the case with the fat 
of the higher animals. 

In the Animal Sphere, the movements are especially de- 
serving of all consideration. As the lowest animals in general, 
so does Actinoplirys move entirely without the intervention 
of muscles or nerves ; but besides this, it presents the pe- 
culiarity that the whole parenchyma of its body in all its 
parts, including the tentacular filaments, is contractile. All 
the motions of Actinophrys are performed with the utmost 
slowness, so slowly, in fact, that it is only by prolonged atten- 
tion to one point, and still longer to the whole form, that it 
can be perceived. In the first place are to be mentioned the 
tentacular filaments, in which numerous changes of form, such 
as elongation, shortening, local swelling, bending, &;c., may 
most readily be observed, whilst at the same time with them 
the scattered granules in their substance move here and there, 
although even in this case the utmost slowness is the rule ; a 
quick movement is never seen. It is especially interesting to 
observe that the filaments, singly or together, frequently dis- 



32 KOLLIKER ON ACTINOPHRYS SOL. 

appear entirely, entering at last, as it were by continued re- 
traction, into the substance of the body, and leaving no trace 
of their former existence ; and that they reappear with the 
greatest readiness and with tolerable rapidity (figs. 3, 4). This 
disappearance and reproduction must be regarded in the same 
light as the similar phenomena in Amceba, in which the processes, 
as is well known, are of a very ephemeral nature ; the author 
has frequently observed the phenomenon, and particularly in 
the reproduction of the filaments, very clearly seen, how the 
homogeneous substance forming the periphery of the body was 
first elevated into minute warty eminences (fig. 4), which soon 
become papillary (the ' proboscis ' of Ehrenberg is probably 
nothing more than one of such papillae), then conical, and 
are finally produced into a long filament. Whether the fila- 
ments which disappear are always reproduced in the same spot 
is not determined ; in some instances this did not appear to 
be the case, although in every instance the number and posi- 
tion of the filaments is pretty constant. Aciinophrys, not 
merely in the form of its processes, and their slow movements, 
but also in this respect, differing altogether from Amaba. 

In the rest of the body itself, movements are well and 
clearly perceptible only in the reception and expulsion of the 
food and its remains. Otherwise only the most faint indica- 
tions of contraction are apparent in it, such as a slight undula- 
tion of the border and inconsiderable quivering motions liere 
and there. 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 in toto. More extensive and more 
energetic movements do not occur at all, and the author con- 
sequently is altogether ignorant as to how locomotion of the 
animal is effected. That it is active in this respect appears to 
be indubitable, for it was found, for instance, that wlien a 
vessel with several individuals of Actinophrys was emptied 
into a flat glass capsule, they were all at first scattered about at 
the bottom, but subsequently, after about twelve to twenty-four 
hours, were all floating at the surface, and indeed at the side of 
the capsule. Elirenberg and Eichhorn assert that the ascension 
in the water of Actinophrys is effected by the taking in, and 
their descent by the giving out, of air. But this is certainly 
not the case, for whence could they obtain this air ? Can it 
be said that they secrete it within themselves like fishes ? In 
that case it must be visible. It appears to the author more 
natural that the rising and sinking should be effected by alter- 
nate contractions and expansions of the whole body. Other 
motions can affect both the (ilanients and the body, but in 
any c ase only through tlie sh)west possible contractions. 



KOLLIKER ON ACTINOPHRYS SOL. 33 

Pulsating spaces, of which Siebold * describes two, imme- 
diately under the integument in Actinophrys, were never seen 
by the author, in as far as Siebold means such spaces as ap- 
pear and disappear. If, on the other hand, he means only 
expansions and contractions of the substance bounding the 
vacuoles, but not such as to cause their disappearance, I 
entirely agree with him, and have seen, as is stated above, not 
two such only, but several. 

Sensation also must certainly be assumed to exist in Actino- 
phrys, only in it, as in the lower animals generally under this 
term, nothing like the conscious sensibility of man is to be 
understood ; but rather, if a comparison must be drawn, may 
it be considered to resemble the condition present in the 
spinal chord and in ganglions, when reflex excitement in them 
is produced through nerves of sense. 

ActinophrTjs perceives mechanical influences, and reacts 
upon them by movements. This is proved by what takes 
place when animalcules, iScc, remain affixed to its tentacles, 
and moreover by the circumstance that when the water in 
which it is contained is carelessly agitated, every Actinophrys 
contracts its tentacles, and even makes them disappear alto- 
gether, and, indeed, with greater speed than is otherwise per- 
ceived in these creatures, and when all is c^uiet they are again 
protruded. These filaments consequently may just as well be 
called tactile as prehensile ; or it may more generally be said 
that the substance of the body is both contractile and sen- 
sitive. 

Under the head of the Reproduction of Actinojjlirys, the 
author's observations are extremely defective. Eichhorn and 
Ehrenberg would seem to have observed spontaneous fission, 
but it' is not said whether these observers concluded that this 
takes place only from the occurrence of individuals apparently 
partially divided, or whether they have actually witnessed the 
production of two individuals from one. This is much to be 
regretted, since, as will be apparent, partially divided indi- 
viduals of Actinophrys by no means demonstrate the existence 
of fission in this case. The author saw what follows : — Upon 
persevering inspection of a biscuit-shaped individual in which 
from analogy he expected to see nothing but that it was soon 
about to undergo division, he was not a little astonished to 
see it gradually assume an oval form, and finally to become a 
single individual. At first he placed no importance on this 
observation, and thought merely that his inquiry on the sub- 
ject of reproduction had miscarried, but as he soon afterwards 
ao-ain noticed the same thing in a second individual, the matter 
appeared too remarkable to be passed over. He adverted to 
* Vers. Anat., pp. 20, 22. 

VOL. I. O 



34 KOLLIKER ON ACTINOPIIRYS SOL. 

the conjugation of the lower algae, and devoted himself 
specially to the investigation of this point. 

After some time thus engaged, he succeeded in one case in 
observing through all the stages of the process " the complete 
fusion into a solitary larger animal, of two individuals, origin- 
ally perfectly distinct." The resultant individual was in no 
respect different from other single individuals, and it presented 
no trace whatever of its having been formed out of two. He 
was now very anxious to know what would becomie of it, and 
actually observed it for a whole day without noticing anything 
peculiar with respect to it. He then lost it by accident, and 
was otherwise, also, unable, as he was obliged to discontinue 
his observations, to follow the thing further : and he has been 
obliged to leave the question undetermined whether or no the 
fusion of two animals into one has anything to do with their 
propagation. Of other facts connected with this subject, it 
may be mentioned that the smallest individuals measured only 
0"01"' — 0'02 ', and presented very inconspicuous and few 
vacuoles, and secondly, that, perhaps, the above-described gra- 
nular and vesicular corpuscles within the nuclear portion of the 
body might be germs just beginning to be evolved. Whether 
this is the case, must be left to future observation to decide ; 
but so much must be remarked, that multiplication hy means of 
germs generated in the interior indubitably occurs in certain 
Infusoria; the author has noticed in E^iglena 4 — 6 embryos 
in one individual, and entirely filling it, which at last, furnished 
with their red point and cilia, broke through their parent, 
leaving it an empty case. 

[To be continued.] 



On the Microscopical and Chemical Examination of the Mantle 
of certain Ascidians. By Dr. H. Schacht. Miiller's 
Archiv. 1851. p. 176. 

It is known that a substance having the chemical relations of 
cellulose was first shown by C. Schmidt (Zur vergleichenden 
Anatomic der wirbellosen Thiere, 1845, p. Gl) to exist in the 
mantle of certain Ascidians ; and the fact was confirmed by 
the chemical and microscopical researches of Kolliker and 
Lowig (Ann. d, Sc. Nat., 1846, p. 193), who extended their 
valuable oljscrvations over a great number of genera and species. 
Roth Schmidt, Kijlliker and Lowig proved the existence 
of the cellulose only by chemical analysis, but not by the 
application of re-agents under the mif roscope ; they found in 
the mantle of the Ascidians a substance not affected either by 



SCHACHT ON THE MANTLE OF CERTAIN ASCIDIANS. 35 

hydrochloric ackl, or by caustic potass, and which, after this 
treatment, bein<? heated with potass, gave out no ammonia, and 
was consequently free from nitrogen. 

According to the latter observers the substance consisted — 

In rhallusia mamillaris : In Cynthia papillata : 

Of Carbon . . 43-40 . . • .43-20 

Hydrogen . 5-68 . . . . 6-10 

Oxyden . . 51-32 . . . . 50 G4 

According to Schmidt, in Pliallusiay 100 parts contained — 

Carbon . . . . 45'38 
Hydrogen . . . 6-47 

The microscopic examination was made by Kulliker and 
Lowig, both before and after treatment of the mantle with 
hydrochloric acid. The form, and, for the most part also, the 
external condition of the mantle remained almost unchanged 
under this treatment, except that in Cynthia, the exterior 
coriaceous layer became smoother and more flexible. Accord- 
ing to them, but in opposition to Schmidt's supposition, the 
Polypes and Medusae contain no cellulose. 

The methods I have followed in my investigation, though 
different from those pursued by him, yet serve in general to 
confirm Kolliker's observations ; but since my researches 
appear to afford further information on some not unimportant 
points, particularly with respect to the condition of the cells 
in the inantle of Phalliisia, and the fibres in that of Cyntlda, I 
feel justified in communicating their results. 

I examined thin, longitudinal, and transverse sections of the 
mantle, first in water and afterwards in succession under various 
chemical re agents, such as a solution of iodine, a solution of 
iodine in chloride of zinc, iodine and sulphuric acid, solution 
of caustic potass, concentrated sulphuric acid, &c., in exactly 
the same way as that in which 1 had already examined all 
vegetable tissues. The species examined were — Pliallusia 
mamillaris, Cynthia microscosmus, and a new species, probably 
allied to Cynthia, from Chili. 

I. Phallusia mamillaris. — In the mantle of this Ascidian, 
according to Kolliker and Lowig, there are three layers per- 
ceptible, — an internal, consisting of an epithelium with cell- 
nuclei ; a middle layer, which in a homogeneous substance 
contains crystals and cell-nuclei ; and a third layer, which 
forms the chief substance of the mantle : numerous, much rami- 
fied vessels proceeding from the heart penetrate the latter, and 
which, at tlie surface of the mantle, appear to pass into other 
vessels which accompany them in their course. The elements 
of this layer are large, elegant cells, imbedded in a clear homo- 
geneous substance, continuous with the principal substance of 

I) 2 



oO SCHACHT ON THE MANTLE OF CERTAIN ASCIDIANS. 

the second layer. The largest of these cells, measuring on the 
average 0-02 — 0-03"', and which were regarded by Wagner 
as cartilage-cells, according to Kolliker and Lowig, correspomi 
with no animal cells hitherto known, except those of the 
chorda dorsalis of some animals. After treatment Avith potass, 
the epithelial cells, the nuclei, and the pigment- cells, which 
occur here and there, disappear, together with the vessels ; 
whilst, on the contrai-y, the substance of the second layer and 
the corresponding substance between the cells, together with 
the latter, remain undissolved. Kolliker and Lowig therefore 
regard both the substance in which the nuclei and cells lie, as 
well as the membrane of the cells itself, as non-nitrogenous — 
as cellulose. 

The fleshy verrucose mantle of Phallusia mamillaris also, 
according to my investigations, presents the three layers above 
described. The innermost layer is separable as a thin mem- 
brane from the rest of the substance of the mantle ; upon it 
lies a layer of very regular epithelial cells, a true tesselated 
epithelium, the cells of which still exhibit traces of a nucleus. 
This membrane itself is coloured blue by iodine and sulphuric 
acid, and is of a fibrous structure, with scattered nuclei ; the 
epithelium acquires a brown colour. When boiled in caustic 
potass, the membrane contracts, without being dissolved, how- 
ever ; and when torn in this condition, its fibrous structure 
becomes still more evident. The epithelial cells disappear 
under this treatment. Upon or beneath this membrane lie, 
scattered here and there, large cells with granular contents, 
which, when warmed, does not become fluid, and therefore 
cannot be any readily congealed fat. When these cells are 
ruptured the substance breaks up into granular portions ; I 
regard them as pigment-cells. 

The second layer, demonstrated by Kolliker and Liiwig, 
constitutes about l-6th of the entire thickness of the mantle ; 
it passes insensibly into the main layer ; the principal vas- 
cular trunks lie in this layer, and in it they give off branches 
which ramify in all directions as far as the border of the 
mantle. The chief vascular trunks which enter the mantle in 
a radiating manner from one point of the animal (according to 
Kolliker, the heart), exhibit in their interior spirally ascending 
fibres, whence they resemble the tracheic of insects ; this struc- 
ture does not exist in the smaller branches. The substance 
in which these large vessels are placed is homogeneous, with 
numerous elongated and round nu( lei, but here and there there 
is a minute isolated cell, and still more rarely a group of 
crystals. Immediately under the readily detached epithelial 
membrane, the substance appears in places to be striated 
(fil)rous), and after boiling with caustic potass this appear- 



SCHACHT ON THE MANTLE OF CERTAIN ASCIDIANS. 37 

ance becomes more distinct. The entire substance of this 
layer is coloui'ed blue by iodine and sulphuric acid, the nuclei 
and vessels turning yellow ; on being boiled with caustic potass 
the two latter are dissolved, the substance itself contracts, but 
is not otherwise altered ; concentrated sulphuric acid dis- 
solves it almost entirely. The third layer, which constitutes 
four or five-sixths of the thickness of the mantle, com- 
mences very insensibly below the large vascular trunks : it 
is at first distinguishable by the appearance of cells and 
the diminution of the cell-nuclei, which latter acquire a 
more irregular, frequently stellate figure, and in this con- 
dition strikingly resemble the bone-cells. The number and 
size of the cells increase in proportion to the diminution 
of the nuclei ; the cells, which, at the commencement of the 
layer were more elongated, become more and more rounded, 
and more closely aggregated, but still not so much so as 
to interfere with their spherical form. At the outermost 
border of the mantle the cells again become somewhat smaller, 
which is best seen by boiling a portion of the mantle from 
this situation, in caustic potass. The external surface of the 
mantle is irregularly beset with short blunt columns composed 
of crystals ; these crystals are insoluble in hydro-chloric acid ; 
sulphuric acid appears to attack them but very slowly. They 
cannot therefore well be carbonate of lime, as supposed by 
Kolliker and Lowig. The outer surface of the mantle, like 
the inner, is covered with a tesselated epithelium, but the 
existence of this epithelium is here much more difficult of 
demonstration, and it does not seem to be retained in all parts. 
It is most certainly seen in thin horizontal sections on the addi- 
tion of sulphuric acid. In the middle, and on the outer border 
of this layer, the nuclei are proportionately rare ; the much 
ramified branches of the large vessels extend as far as the 
border of the mantle, where they terminate in clavate dilata- 
tions. Sometimes, it is true, it appears as if one or other 
branch of these vessels ran backwards into the substance of 
the mantle, but a double vascular system, as described by 
Kolliker and Lowig, I have nowhere been able to detect. 

In a very thin section, under water, a peculiar, excessively 
delicate marking is perceptible in the thin cell-membrane, 
surrounded by the transparent interstitial substance, which 
marking in some cases might be taken for a closely wound 
spiral, but which, as I have satisfactorily ascertained, depends 
upon a folding of the membrane, due in all probability to the 
influence of the spirit in which the specimen had been kept. 
The form and appearance of the cells is the same in whatever 
plane they are viewed ; they are not placed at any uniform 
distances apart. At the boundary between this and the second 



38 SCHACHT ON THE MANTLE OF CERTAIN ASCIDIANS. 

layer the formation of new cells appears to take place in the 
interstitial cellulose substance, without the intervention of a 
mother cell. The cells are invariably without a nucleus or 
any visible cell-contents. 

Iodine colours the thin, somewhat granular-looking mem- 
brane of the cells in question yellowish, and the above de- 
scribed marking appears then more distinctly, and minute 
opaque granules show themselves in the furrows between the 
folds. The interstitial substance in thin sections is scarcely 
coloured ; in thicker it appears yellowish. 

If a thin section be touched with a solution of iodine, which 
is afterwards removed with a fine hair pencil, and a drop of 
sulphuric acid added by means of a glass rod, the section is 
immediately coloured a dark blue. It is not the cells which 
are coloured blue but the insterstitial substance. The thicker 
parts of the section do not acquire the blue colour till after- 
wards, frequently not for several hours. 

If, on the other hand, a similarly thin section be moistened 
with the solution of iodine in chloride of zinc, the interstitial 
substance remains colourless, even when the section has been 
previously allowed to dry upon the glass. The cellulose of 
plants on the other hand, in general, if not immediately, 
yet after some time, appears to be coloured a beautiful blue 
or violet by this re-agent. The cellulose of the higher Algae 
(C/ioJ'daj'ia, Fucus serratus, Chondrus crispus) behaves in this 
respect like that in the mantle oi Phallusia, and is not coloured 
by the ioduretted solution of chloride of zinc. 

If to a thin, scarcely moist section, be added a drop of con- 
centrated sulphuric acid, and its action noted, it will be seen 
to take place from the edge of the section towards its centre ; 
the membrane of the cells contracts, and the markings, caused 
by the folds, disappear, though the minute granules contained 
in the furrows remain. The cell-membrane exhibits precisely 
the same re-actions as does the primordial sac of the vegetable 
cell. In proportion to the contraction of the cells the inter- 
stitial substance swells out, by which the distance between the 
cells is increased. The swollen interstitial substance is not 
optically recognizable. If now a drop of a solution of iodine 
]ye added, and allowed to enter from the side between the slips 
of glass, there appears at the limits of the intermingling fluids 
a brownish violet zone of a granular consistence as seen under 
the microscope. The solution of iodine is prevented by the 
swollen interstitial substance from penetrating farther, but if 
the cover is raised and again let fall after the solution of iodine 
has l)ecome mixed with the sulphuric acid, the whole assumes 
the appearance of a more or less clear, and more or less in- 
tensely blue membranous substance — the swollen interstitial 



SCHACHT ON THE MANTLE OF CERTAIN ASCIDIANS. 39 

substance — in which the ahnost imperceptible remains of the 
cells are lodged. 

If a thin section be treated with sufficiently strong hydro- 
chloric acid, there ensues, even after several hours, no colour- 
ing or other perceptible change either in the cell-membrane or 
in the interstitial substance, nor have I ever succeeded by the 
use of sugar and sulphuric acid in producing a manifest rose- 
red colour in the probably nitrogenous cell-membrane. 

If a thin section be warmed for a minute in sufficiently 
strong solution of potass, it is not disintegrated ; the membrane 
of the cells disappears entirely if the section were thin enough, 
and the re-agent has acted sufficiently ; the interstitial sub- 
stance becomes somewhat contracted ; the hollows in which 
the cells had been contained on this account appear smaller. 
Tlie addition of a solution of iodine now colours the interstitial 
substance yellowish, in an hour clear brown-violet ; a fresh 
addition of the iodine solution exalts this colour ; after twenty- 
four hours the section appears red-brown, like the colour of 
burnt terra de Sienna. loduretted chloride of zinc solution 
immediately colours a section that has been boiled in potass of 
a beautiful violet blue. 

If small pieces of the mantle be macerated for 2+ to 3 
minutes in chlorate of potass and nitric acid, the substance 
during maceration assumes a citron yellow colour, which dis- 
appears on the addition of water. The substance is not dis- 
integrated, and may be cut just as readily after the maceration 
as before it ; nor is any change perceptible under the micro- 
scope either in the cell-membrane or interstitial substance. 

If, however, thin sections of the mantle are macerated in 
the same way for only a minute, the section does not become 
corrugated, assumes a yellow colour during the maceration, 
which disappears in water. The interstitial substance has not, 
as on the application of caustic potass, become contracted, the 
cells have not disappeared, though less distinctly marked than 
before ; their membrane appears, as previously, rather granular, 
nor is it changed in the folds. The addition of solution of 
iodine scarcely produces a yellow colouring of the cell-mem- 
brane, the interstitial substance is not coloured, nor does the 
loduretted chloride of zinc solution produce any effect — no 
blue colour being elicited even after several hours. Iodine and 
sulphuric acid however produce precisely the same blue colour 
of the interstitial substance as before the maceration ; the 
pieces of the mantle which had been macerated 2ito 3 minutes 
behave in exactly the same way towards the same re-agent. 
[To be continued.] 



( 40 ) 



REVIEWS. 



Lectures on Histology, delivered at the Eoyal College of Surgeons of 
England, in the Session 1850-51. By John Quekett. London. 
Bailliere. 

Amongst the many admirable arrangements of the College 
of Surgeons in London is the delivery by the Professors of 
courses of lectures on what may be called the science of 
organization. In the lectures delivered by Professors Owen, 
Paget, and Quekett, the object of the College of Surgeons in 
relation to the profession of surgery is not lost sight of, but 
they have the higher object in view of illustrating the great 
museum which the industry of John Hunter commenced, and 
of exhibiting the spirit in which that profound genius laboured 
to unfold the laws of organization. Already science is deeply 
indebted for the contribution which the publication of many 
of these lectures has made to its literature. We may name 
more especially the pliilosophical lectures of the Hunterian 
Professor on Comparative Anatomj^, as amongst the most im- 
portant works of the day upon the subject. 

It was not to be expected that the Council of the institution 
that was entrusted with the charge of John Hunter's museum 
would neglect the opportunity which recent improvements of 
the microscope afforded, of prosecuting by its aid the re- 
searches which that great philosopher had commenced. It 
was fortunate that in Mr. Quekett they found a man whose 
tastes, habits, and education peculiarly fitted him for prose- 
cuting inquiries with this instrument. Unbiassed by the 
views of others, not given to speculation, delighting in delicate 
manipulation, and possessed of a patience unwearied as long 
as now subjects were to be examined or new facts observed, 
he was just the man to contribute to the histological parts 
of the museum, and to demonstrate the minute anatomy of the 
tissues. Under his superintendence the histological demon- 
strations became speedily popular, and as the result, his 
remarks on the preparations submitted to his class have been 
published in the form oi these ' Lectures on Histology.' This 
title might however mislead, as this work is not a complete 
treatise on liistology, nor intended to eml)race the wliole of 
this wide field of science. Tliey consist of a series of remarks 



QUEKETT'S LECTURES ON HISTOLOGY. 41 

with reference to objects and preparations wliicb were intended 
to illustrate a particular series of facts. The object of the 
present volume is the elementary tissues of plants and animals, 
and even these are not treated at all in an exhaustive manner. 
The work therefore must not be regarded as a manual or 
outline of the subject of histology, but as the remarks of an 
observer whose opinions are always of value, over a wide and 
important field of microscopic research. 

The first part of the work is devoted to the tissues of 
plants, the second to the tissues of animals. We are glad to 
find that Mr. Quekett has devoted so much space to vegetable 
tissues, as there can be no doubt that the best introduction to 
the more difficult problem of cell-growth in animals is the 
study of the phenomena presented by the cells of plants. The 
vegetable and animal kingdoms, with a wonderful distinction 
in form and functions, liave yet relations so close, and a 
dependence so absolute, that the principles which regulate the 
growth and functions of one cannot be understood without 
reference to the other ; and researches, prosecuted by the aid 
of the mici'oscope, are every day increasing our knowledge of 
the details of this great fact. 

Mr. Quekett commences with an account of the old " ele- 
mentary tissues " of the botanist, " membrane and fibre." It 
should, however, be recollected, that amongst plants there is 
no membrane, as there is in some animal structures, indepen- 
dent of the cells. The vegetable membrane referred to here 
is simply the cell- wall, which varies very much in form and 
properties in different cells. So with fibre. We well know 
there is no fibre independent of cells, and fibre is but one 
form which the deposits in the interior of cell- walls exhibit. 
There is no advantage to be gained in treating of these subjects 
independent of the cells in which they are found. 

From a chapter entitled ' On the Forms of Cells,' in which 
several of the principal forms of plain cellular tissue are 
noticed, we pass to the contents of cells. Under the head of 
' Starch ' we find the properties of the common forms of this 
substance alluded to. Mr. Quekett adopts the term " hilum," 
as applied to the circular spot seen in the majority of starch 
granules ; but this term is objectionable, as involving the idea 
of the attachment of the starch granule to the cell, which is 
not the case. Fritsche's term nucleus is better when this 
spot is obvious. This nucleus is mostly seen to be surrounded 
by curved lines, and which have been supposed to indicate 
that the starch is composed of a series of layers which have 
been consecutively deposited. Mr. (Quekett however decides 
this, and says " tliey are confined to the cell-wall, and are 



42 QUEKETT'S LECTURES ON HISTOLOGY. 

most probably mere transverse thickenings or rugae in the 
membrane, of which, together with its amylaceous contents, 
the starch- gi-anule consists." This statement is at variance 
with the observations of Payen and Persoz, and of Schleiden, 
who maintain not only that the starch-granule is composed of 
several layers of differing density, but that there is no envelop- 
ing membrane, the whole granule consisting of a homogeneous 
mass. Schleiden says most emphatically, as the result of a 
long series of experiments on the action of iodine, that " there 
never was the most remote indication of there being any part 
in the starch-granule which was not equally coloured by it." 
Speaking of the potato disease Mr. Quekett says : — 

" Before leaving the subject of starch, alhision may be made to the re- 
cently ])revalent and desti-uctive epidemic among the potatoes, which I 
believe to have been a disease of the tuber, not of the haulm or leaves. 
Examined in an early stage, such potatoes are found to be composed of 
cells of the usual size, but they contain little or no starch ; and hence it 
may be inferred, that the natural nutriment of the plant being deficient, 
the haulm dies, the cells of the tuber soon turn black and decompose, and 
fungi are developed as on most other decayed vegetable substances." 

This will undoubtedly explain the most prominent symptom 
of the potato disease — the tendency to decomposition, — and 
is a point in which the microscope confirms the result of 
chemical experiment, for it has been found that the diseased 
potatoes contain a larger proportion of water than those which 
are healthy. A want of organizing power is evidently the 
cause of this deficiency of starch, but we fear the microscope 
will never tell us in what the want of this organizing force 
consists. 

Under the head of raphides there are some interesting 
remarks, but as in the portion of the Transactions of the 
Microscopical Society, which we publish in this Number, 
Mr. Quekett enters so fully into this subject, we shall pass 
it over, only observing that we cannot agree with him that they 
are accidental bodies. In many of the plants referred to, 
these bodies are constantly found, and we question if a speci- 
men of any of them could be found in which these bodies 
are absent. Although Mr. Quekett has separated silica from 
the raphides, we cannot but think that the deposits of this 
substance in the tissues of vegetables are of the same nature 
as that of other inorganic compounds. It is true that the 
function of silica, as deposited in the stems of grasses, palms, 
and Dutch rushes (Kquisetacea^), is more obvious than that of 
oxalate of lime in the roots of rhubarb, but the one is not 
less constant than the otlier. In the family of Corallines we 
find carljonatc of lime not loss necessary to their existence 
than the silica of the Diatomaceac. VVhat the relation of 



QUEKETT'S LECTURES ON HISTOLOGY. 43 

these inorganic matters to the tissues of plants really is, may 
be seen in the perfectly analogous deposit of the same 
substances in the Polypiierac and Spongiadae in the animal 
kingdom. 

In allusion to the distinctions between the Diatomaceae and 
Desmidese, Mr. Quekett says that the latter have a horny, in 
place of a siliceous structure. The horny character, however, 
of the Desmidea^ is not dependent on gelatine but on cellulose, 
as we have frequently observed, by the application of sul- 
phuric acid and iodine, when the cellulose is converted into 
starch and coloured blue by the iodine. 

The use of the Diatomaceae as food as they occur in the 
Berg-mehl of Sweden, seems to be regarded by Mr. Quekett 
as dependent on the silica they possess. We think it is much 
more likely to be on account of the layer of organized matter 
by which their siliceous skeletons are surrounded, and if we 
mistake not, this is the explanation given by Ehrenberg, who 
first demonstrated the true nature of this interesting substance. 
The part performed by Diatomaceae in the creation is not yet 
fully understood. Of all organisms they are most abundant. 
Dr. Hooker found them discolouring the seas of the South 
Pole, and in the lava of the volcanic luountain Victoria. They 
are found in the greatest abundance in rivers, lakes, ponds, 
and ditches, and if in the purest water an organic being or 
two are found to be present, they are sure to be Diatomaceae. 
The late Mr. Edwin Quekett discovered a highly interesting 
set of forms of them in the guano of Peru, and his brother 
suggests that this manure may owe something of its value to 
the siliceous matter which it thus contains. We have much 
to learn with regard to the history of these beings, the existence 
of which the microscope alone informs us, and we are glad 
to know that we are shortly likely to have the results of 
several years' careful examination of them from the Rev. Mr. 
Smith. Messrs. Ralfs and Jenner have also been labouring at 
this department of inquiry, and have partly promised a work 
on the subject, through the means of the Ray Society. 

Under the head of ' Sclerogen,' Mr. Quekett has given a 
number of examples of those forms of cellular tissue in which 
the cell-walls are of unusual thickness and hardness. A 
knowledge of these is not only interesting, as illustrative of 
the great variety of cell-growth, but is not unfrequently of 
practical value, as the following cases prove : — 

*' A knowledge of these hard structures is often of considerable impor- 
tance, much more so, indeed, than many are apt to imagine. The fol- 
lowing is an example of the practical utility of such an acquaintance with 
miinite structural anatomy : — About two years since, I received from a 
medicari gentleman in the country, some specimens mounted as micro- 



44 QUEKETT'S LECTUKES ON HISTOLOGY. 

scopic objects, that bad beeu passed from the bowels by a female. One of 
them I found to be the cuticle of a plant, and this turned out subsequently 
to be the cuticle of a goosebeiTV ; the other puzzled me, but I made up 
my mind that it also was of vegetable origin, and that it was, in all pro- 
bability, the testa of some seed. I wrote to my correspondent to this 
eifect, but the patient denied having eaten any dried fruit for the space of 
twelve years, and the physician, believing the slatement of his patient, 
considered that the microscopist was in error. I, however, still maintained 
my point, and when preparing the series of specimens known as hard 
tissues, for the Histological Catalogue of the College of Surgeons, I 
examined, among other things, the tamarind, and in the testa of the seed 
found the disputed structure. I subsequently learned that the patient 
was the daughter of a grocer, and might have had free access to the 
tamarind jarT This is another instance of the value of the microscope to 
our profession." 

Vegetable physiologists would have been glad of Mr. 
Quekett's opinion on the structure of the embryo, and espe- 
cially on the question of the entrance of the pollen-tube into 
the sac of the embryo. He has not, however, alluded to this 
subject. He has, however, some remarks on the structure of 
Spermatozoids or Phytozoa, which are now known to exist in 
so many of the Cryptogamia. He has not examined these 
extensively. Although he has not alluded to the movements 
of these bodies as dependent on ciliary motion, there is 
no doubt that in the fems at least they are supplied with 
cilia, which produce their movements. This subject is one 
which still offers a rich field of investigation for the micro- 
scopic observer. To those who wish to pursue this subject, 
we would recommend Dr. W. Hofmeister's work on the 
Germination, Development, and Fructification of the higher 
Cryptogamia. (Vergleichende Untersuchungen der Keimung, 
Entfaltung, und Fruchtbildung hoherer Kryptogamen, 4to., 
Leipsic, 1851), and also the excellent report on this subject 
by Mr. Henfrey in the last volume of the Transactions of the 
British Association. 

From plain cells and their contents we come to fibro- 
cellular tissue, to plain vascular tissue, such as that which is 
called woody, and the various forms of fibro-vascular tissue. 
In his treatment of these subjects the Professor has not followed 
any definite plan. All vegetable tissue is a modification of the 
cell, and any classification artificial. For practical purposes 
the term vascular may be applied to cells or tissue longer than 
it is broad, whilst cellular should be confined to tissue that is 
not longer tlian it is broad, and they may each be called fibro- 
vascular and fibro-cellular, as they present fibrous deposits, or 
their modifications in the interior. In speaking of the vegetable 
tissues used in the arts, Mr. (^uekett has pointed out how the 
microscope may be successfully employed in distinguishing 
the various kinds of woody fibre used in the manufacture of 



QUEKETTS LECTURES ON HISTOLOGY. 45 

clothing. The microscope may thus be made to throw light 
on the habits and manners of nations of antiquit3^ Tlius it 
has shown that all Egyptian mummy-cloth is made from the 
fibres of the flax, whilst it has demonstrated that the mummy- 
cloth of Mexico is cotton ; thus at once throwing a light on 
the habits of the ancient inhabitants of the New and Old 
World ; the one being engaged in the culture and manufacture 
of cotton, the other in that of flax. 

Tlie analogy between the structure of spiral vessels and the 
tracheae of insects has not been lost sight of, and some in- 
teresting instances of both are given. Similar as these things 
appear we very much question if their mode of development is 
the same. They afford interesting examples of a principle 
which we often see carried out in nature of the greatest amount 
of strength with the least amount of material. The importance 
of this in insects will be at once felt when we reflect that 
many of them spend the greater part of their existence sus- 
pended in the air by means of their wings. We also find the 
spiral vessels of plants in positions where the same principle 
can be clearly seen to be of advantage. Whatever may be the 
resemblance in structure between these two parts there is no 
reason for supposing an identity of function. Reasoning from 
analogy of structure to that of function is always very unsound, 
for even amongst structures that are homologous we frequently 
find variety in the functions performed. Take the wings of 
a bird and the upper extremities of man, the swimming 
bladder of the fish, and the lungs of the mammalia. 

In the section on spiral vessels Mr. Quekett mentions a fact 
that we do not remember to have seen previously noticed, the 
existence of membrane that tears up and unrolls in a spiral 
manner. This has been observed in the hairs found on the 
outside of the fruit of Cycas revoluta. There is one other 
subject we would allude to before leaving the botanical sec- 
tion, and that is the lactiferous or milk-vessels of Schultz. 
The branched character of these vessels makes them quite ex- 
ceptional amongst vegetable tissues. It has been asserted that 
they are not true tissue at all, but are intercellular passages 
which have acquired the appearance of vascular walls from the 
deposits of the fluids which pass through them. At any rate 
we know little or nothing of their development, and this is 
a subject open for investigation at the present moment. 

This part of the work concludes with the following 
sentence : — 

"One great object which I have kept in view tliroughout, has been that 
of endeavouring to impress on you the faot, that each cell of a plant should 
be considered as having an independent or individual existence ; that in 
one situation it may secrete colouring matter, in another starch, gum 



46j * THE MICROSCOPE AND ITS APPLICATION. 

sugar, oil, &c. ; and in another the material for the reiiroduction of its 
si^ecies." 

We are convinced that too much importance can scarcely 
be attached at the present day to the study of the cell as an 
individual. Many of the theories of vegetable function which 
have been hitherto received will not bear the test of an accurate 
knowledge of the functions of the individual cell. The young 
vegetable physiologist cannot do better than commence his 
studies, microscope in hand, with observations on the develop- 
ment and functions of the individual cell. 

Want of space compels us to stop here ; we shall probably 
recur to the remaining part of Professor Quekett's work in our 
next number. 



Das MikrosJwp, und seine Anwendung, 8fc. {The Microscope 
and its application, especially to Vegetable Anatomy and Phy- 
siology.^ By Dr. Hermann Schacht. Berlin. 1851. 
Pp. 200. 
The deservedly high reputation of Dr. Schacht as an 
accurate microscopical observer and excellent phytologist, 
and which has recently been much enhanced by his recent 
work on vegetable histology,* renders a book on the micro- 
scope and its use, from his hands, well worthy of consi- 
deration and respect. The limited scope of the present work, 
which is confined almost exclusively to botanical subjects, 
is much to be regretted. Had a chapter or two, having 
reference to the modes of procedure to be adopted in the 
investigation of animal tissues and other subjects, and in 
the same precise and satisfactory style, been added, the work 
would constitute a very complete and comprehensive manual 
of microscopy. The subject, however, to which it is more 
particularly devoted — the structure and development of vege- 
table tissues — is in itself one of great general interest and 
importance, and the author's treatment of it such as to justify 
our highest commendation. 

After a few sensible introductory remarks on the use of the 
microscope in general, and the difficulties at first attendant 
upon its employment, the author proceeds to a description 
of the compound microscope. As, however, he appears to be 
familiar only with instruments of continental make, and to be 
altogether unacquainted with any of English construction, and 
consequently with many of the more recent improvements, 
introduced chiefly l)y lOngllsh makers, not only in object- 
glasses, but more especially in the various modes of illumi- 

* Die Pflanzcnzellc, Die inncre r.an iiiul das Lcbon dcr Gcwachso. 
licrliii,18.'-)2. ly 472. 



THE MICROSCOPE AND ITS APPLICATION, 47 

nation, which have latterly occupied so much and so deservedly 
the attention of opticians, it is not necessary farther to refer 
to this part of his work than to observe that he gives the pre- 
ference, above all other continental instruments, to the larger 
microscope by Oberhauser of Paris. This much-vaunted in- 
strument we have not seen, but, from the description and 
figure of it given by Dr. Schacht, its very great inferiority, in 
the mechanical arrangements of the stand at all events, to those 
of our London makers, is at once apparent. 

One result of the Great Exhibition of last year was incon- 
testably to prove the superiority of English microscopes ; and 
it is clear also from Dr. Schacht's observations, — and he boasts 
of an extended acquaintance with the microscopes of nearly 
all continental makers of any eminence, — that what he con- 
siders an instrument of the best possible kind would in most 
respects here be regarded in a very different light. So much 
in justice must be said on the part of English opticians. 
Can the same favourable comparison l)e drawn between 
English observers and their continental brethren ? In some 
respects, and especially, perhaps, with reference to animal 
physiology, anatomy, and pathology, we are inclined to think 
it might, in others certainly not; but in any case it should not 
be forgotten that the extreme convenience, elegance, and, as it 
may be termed, luxury, of a first-rate English microscope, are 
quite unessential in the prosecution of research, and many an 
ardent aspirant may be glad to know that, having really good 
object-glasses, he may with a very simple instrument confi- 
dently approach almost any branch of microscopical inquiry. 

Having described the usual appurtenances of a microscope, 
and the mode of using them, the author gives the following 
list of chemical re-agents useful in microscopical inquiries, and 
of preservative fluids, which we have thought it might be 
useful to extract: — 

" 1. AlcoJiol, principally for the removal of air from sections of wood and 
other preparations ; also as a solvent for certain colouring matters. 

" 2. jEther, chiefly as a solvent for resins, fatty and other essential oils, 
&c. ; also useful for the removal of air. 

" 3. Solution of Caustic Potass, as a solvent for fatty matters ; also of 
use occasionally, in consequence of its action upon the rest of the cell 
contents and thickening layers. This solution acts best upon being 
heated. 

" 4. Solution of Iodine (iodine 1 gi'ain, iodide of potassium 3 grains, dis- 
tilled water 1 ounce), for the coloration of the cell membrane and of tlic 
cell contents. 

" 5. Concentrated Sidplmric Acid, employed principally in the examina- 
tion of pollen and spores. 

" 6. Diluted Sulphuric Acid (three parts acid, one part water), for the 
coloration of cells previously immersed in the iodine solution. Tlic pre- 
paration is first moistened with the iodine solution, which is afterwards 



48 THE MICROSCOPE AND ITS APPLICATION. 

removed with a hair pencil, and a drop of sul[iliiiric acid added by means 
of a glass rod ; the preparation is then innnediately covered with a piece 
of glass. The action of the sulphuric acid and iodine, as well as that of 
the iodized chloride of zinc solution, is not always uniform throughout 
the whole surface of the preparation. The colour is more intense where 
the mixture is more concentrated ; it frequently happens that many spots 
remain uncoloured. The colour clianges after some time, the blue being 
frequently changed into red after twenty-four hours. 

" 7. A solution of Chloride of Zinc, Iodine, and Iodide of Potassium. — 
A drop of this compound solution, added to a prcjiaration placed in a little 
water, produces the same colour as iodine and sulphuric acid. This solu- 
tion, which was first proposed and emploj'ed by Professor Schulz of Eos- 
tock, is more convenient in its application than iodine and sulphuric acid, 
and performs nearly the same services, whilst it does not, like the sulphuric 
acid, destroy the tissues to which it is applied, 'J'he precise composition 
is as follows : — 

" Zinc is to be dissolved in hydrochloric acid, and the solution, in contact 
with metallic zinc, is to be diluted to a syrupy consistence, and the solu- 
tion must then be saturated wdth iodide of potassium. Iodine is then to 
be added, and the solution, if necessary, diluted with water. 

" 8. Nitric Acid, or, what is better, chlorate of potass and nitric acid, as 
an agent to effect the isolation of cells. The mode of employing this 
means, also discovered by Professor Schulz, is as follows : — The object — a 
thin section of wood, for instance — is introduced, with an equal bulk of 
chlorate of potass, into a long and moderately wide tube, and as much 
nitric acid added as will at least cover the whole. The tube is then 
Avarmed over a spirit-lamp ; a coj^ious evolution of gas takes i:)lace, upon 
which the tube is removed from the flame, and the action of the oxydizing 
agent allowed to continue for two or three minutes. The contents of the 
tube are then poured into a Avatch-glass with water, from which the 
slightly cohering particles are collected and placed in a tube, and again 
boiled in alcohol as long as any colour is communicated. They are again 
boiled in a little water. The cells may now be isolated under the simple 
microscope by means of needles. The boiling with nitric acid and chlorate 
of potass should never be carried on in the same room with the micro- 
scope, the glasses of which may suffer injury from the vapours. Thin 
sections of vegetable tissue are warmed for half or a whole minute in a 
watch-glass ; boiling is here iinnecessary. The section is taken out, and 
treated with water in a watch-glass. 

" 9. Oil of Lemons, or any other essential oil, for the investigation of 
pollen aird spores. 

" 10. A moderately strong solution of Muriate of Lime (one jjart dry 
muriate of lime, and three parts distilled A\ater), for the preservation of 
microscopical preparations. This is applicable to most things, even for tlie 
most delicate preparations, excepting starch. If it is desired to keep a 
prep»aration, which is not to be retained permanently, for some days, a 
small drop of this solution may be pjlaced upon it, and the whole placed 
under a glass cover to keep it from dust. 

" 11. Glycerine, a.ho fur the ])reservation of microscopical preparations. 
It is well adapted for the preparation of cells containing starch, which re- 
mains unchanged by it. In starch grains, exhil)iting a laminated structure 
— as, for instance, in potato starch — the lamination \s usually not apparent 
for the first few hours, 1)Ut after about twenty-four hours it becomes more 
evident than before. 

" 12. Copal Varnish and Canada Balsam, also used for the preservation 
of microscopic objects. Botli substances can only be employed in the case 
of a few thin sections of wood, especially of fossil woods ; both render tlie 
object more transparent than the solution of muriate of lime. 



THE MICROSCOPE AND ITS APPLICATION. 49 

" 13. Lastly maj^ also be enumerated a pretty strong solution of Car- 
bonate of Soda and also Acetic Acid, which latter, however, is more 
especiallj' useful in the investigation of animal tissues." 

To the above may be added a test for protein compounds, 
which is described by the author in his larger and more recent 
work, ' Die Pflanzenzelle.' This test is composed of sugar 
and sulphuric acid, and is thus employed : — A very thin 
section or portion of the tissue to be examined is placed in a 
drop of simple syrup. This is then removed by means of a 
hair pencil, and a drop of sulphuric acid (three parts acid, one 
part water) added ; the red colour usually does not appear till 
after the lapse of about ten minutes. 

The third chapter contains general rules for the use of the 
microscope, and for the proper disposition and preparation 
of objects ; from which, however, thougli all useful and con- 
cisely expressed, there is little of novel nature to extract. 
Dr. Schacht is of opinion, in which we cannot from expe- 
rience but agree with him, that whoever has regard for his 
eyes will never employ the microscope for prolonged investi- 
gation by artificial light. In his directions for making thin 
sections of tissues, he recommends that, in the case of objects 
whose consistence differs in different parts, the section should 
be carried from the harder into the softer portion. He also 
in some cases recommends a procedure which is doubtless 
familiar to most of our readers, viz. : in the making of a thin 
section of a very minute yielding substance, to enclose it 
between two pieces of cork, and to slice the whole together. 
It is also useful sometimes to saturate the object with mucilage, 
which is to be allowed to dry slowly ; in this way very deli- 
cate tissues may be sliced or otherwise divided without injury, 
and with great facility. 

The fourth, fifth, and sixth chapters enter more specially 
upon the histology of vegetable tissues, and the modes in 
particular cases of pursuing its investigation. They contain 
matter of great utility, but do not admit of condensation. In 
all observations. Dr. Schacht strongly recommends the making 
of drawings of everything worth note observed. He strongly 
deprecates the making of mere diagrammatic figures, which 
only convey the momentary impression made upon the ob- 
server ; in all cases an accurate drawing of the object, 
conveying " the truth, the whole truth, and nothing but the 
truth,'' should, if possible, be made : and in all cases where 
it can be employed, he strongly recommends, and himself 
always uses, the camera lucida. 

The seventh chapter is devoted to the subject of making 
drawings from the microscope, and contains many sensible, 
useful, and minute directions, especially with respect to 
colouring. 

VOL. I. B 



50 THE MICROSCOPE AND ITS APPLICATION. 

The work corulucles with a chapter upon the preservation ol 
microscopic objects, but in which we do not notice anything 
sufficiently novel to warrant extraction, except one proceed- 
ino-, which, as we have had an opportunity of seeing, is well 
worth following, and may perhaps be novel to some. It is 
the mode of preserving preparations of vegetable tissues in a 
solution of muriate of lime, and which, from its simplicity, 
efficacy, and permanence, appears to have much to recommend 
it. It is as follows : — 

" A slip of glass of couvenient size being perfectly cleaned, strips of paper 
are gummed "across it, dividing it into as many compartments as may be 
desired. The strips at each end are rather wider than those between the 
divisions. These strips of paper serve not only for the subsequent joining 
of the two glass slips together, but also to prevent the pressure upon the 
preparations. The paper, therefore, of which the divisions are formed, 
should not be thiimer than the objects, nor, on the other hand, should it be 
much thicker, as in that case the preparations would lie too loose. 

" When these strips of paper are dry, and the glass again carefully cleaned, 
a drop of the muriate of lime solution is be placed in the centre of each 
compartment by means of a thin glass rod. It is advisable first to breathe 
upon the glass, as the drop of solution then adheres more readily to the 
surface. The objects to be set up require to be most carefully prepared. 
Preparations of recent soft objects are rarely treated with alcohol, whilst, 
on the other hand, sections of wood must always first be immersed in 
alcohol to remove resinous matters and air ; but they must not be trans- 
ferred immediately from the spirit to the muriate of lime solution — they 
must first be placed in a watch-glass in water, in order to remove the alcohol. 
From the watch-glass they may be carefully taken bj- means of a hair 
pencil, and conveyed to the drop of saline solution destined for their recep- 
tion. It is often in this proceeding requisite to place the watch-glass upon 
a dark gi-oimd, in order to render the minute objects visible. When all 
the preparations are duly placed on the glass slip, it is brought under the 
simple microscope, and the objects properly laid out hj means of needles 
or otherOTse, and at the same time foreign particles of dust, &c., removed. 

" In the conveying of the preparations, with the hah" pencil, from the 
water to the muriate of lime solution, a dilution of the latter is unavoid- 
able. It is, therefore, very necessary to remove, by means of a larger, 
perfectly clean pencil, the greater part of the solution in which the pre- 
paration is lying, which with' a little care may readily be done without 
disturbance of the object. The fluid thus removed must then be replaced 
b}' an equal ciuantity of fresh solution. The size of the drop must be re- 
gulated according to the thickness of the paper employed to form the 
divisions. The drops of fluid and the contained preparations bemg thus 
arranged, each in the centre of its own division, and the latter properly 
laid out so as to exhibit clearly what thej' are intended to show, a little 
mucilage is smeared over each of the strips of paper, and the covering 
glass carefully placed upon the other, and pressed upon the divisions so 
as to cause it to adhere to them. The ends of the slips are then covered 
with paper, upon which are written remarks upon the preparations, with a 
date, &c. 

•' The chief difficulty in the setting up of preparations in this way con- 
sists in arranging the due quantity of the muriate of lime solution. If this 
lie too small, the preparation will be uncovered by it on one side ; and if too 
great, the fluid comes in contact with the pajjcr forming the strips, and, 
being absorlied b}- it, the preparation is equally left dry. In neither case, 



THE MICROSCOPIST. 51 

however, is it injured, as it is always saturated with the solution ; but as 
in this state it is useless for the puqiose of examination, it is frequently- 
necessary to repeat the entire j^rocess. This is done by immersing the 
slide in water, and, when the slips of glass are separated, the preparations 
are to be again laid out in the way above described. When the process, 
however, has been duly eflected, no further care of the preparation is 
requisite, except the alwaj-s keeping it lying flat." 

Glycerine may be employed in the same way ; but the 
author appears to think that in the employment of this fluid 
it is necessary to close the edges of the space between the 
glasses with some air-tight cement. 



The MiCROSCOPiST ; or a Complete Manual on the Use of the Microscoiie. 
By Joseph H. Wtthes, M.D. Philadelphia. Lindsay and Blakiston. 

The history of the microscope, like that of many other useful 
human inventions, has been a chequered one. When first 
brought into use at the end of the seventeenth and the beginning 
of the eighteenth century extravagant expectations were formed 
of its value — expectations which were almost justified by the 
discoveries of Swammerdam, Hooke, Leeuwenhoek, and others. 
It failed, however, to realise these brilliant hopes, and we 
find the science of observation progressing rapidly from the 
middle of the eighteenth to the beginning of the nineteenth 
century without the aid of the microscope. Linnaeus, the 
great presiding genius of natural history at this period, had 
put his ban upon this instrument, and publicly announced his 
opinion of its worthlessness in the pursuits of the naturalist. 
It, however, maintained its position in the toy-shops, and 
though disregarded by the man of science, it was a successful 
means of exciting the wonder of the ignorant in the hands of 
the mountebank. Even after the improvements of the micro- 
scope in the present century by Brewster, Lister, and others, 
which made it once more an instrument of observation, and the 
discoveries of Brown, Ehrenberg, Miiller, and their contem- 
poraries, it has not lost its hold on the public mind as a source 
of wonder, and a toy with which to pass aw ay hours that would 
otherwise be found wearisome enough. We would not on this 
account propose a classification of those who possess micro- 
scopes into those who use them as toys and those who use them 
as philosophical instruments. It is certain, however, that the 
two classes exist and they probably run one into the other at 
many points, and we only allude to the subject here by way of 
warning to those who use or write upon the microscope to avoid 
the tendency to regard it as a mere instrument of amusement. 
The simplest combination of lenses that can be bought at a 

E 2 



52 THE MICROSCOPIST. 

toy-shop may be made a means of instruction to the children for 
whom they are made. The microscope is, in fact, but an in- 
struinent or tool, and in this respect is like all others by the use 
of which certain ends can be attained and objects effected which 
could not be without its employment. As cutting with a sharp 
instrument is better than tearing with the nails, so vision with 
the microscope is better than with the naked eye. Its use is, 
therefore, as extensive as that of the organ which it assists, and 
it cannot be regarded as the property of one bi'anch of science 
more than another. It is true that in revealing the intricate 
structure of organized beings it has been more extensively 
employed by the physiologist and naturalist than by other 
scientific inquirers, but it cannot be claimed exclusively for 
histology or any other branch of science. But whatever may 
be the department of inquiry in which this important instru- 
ment is employed, the general principle of its construction 
and use are the same, hence the demand for books treating of 
its structure, and explaining the manner of its use and appli- 
cation. Of the various treatises that have been devoted to this 
subject in the European languages, we have no hesitation in 
pronouncing that by Professor Quekett as far the best, and 
we hope in our next number to have an opportunity of noticing 
the srcond edition of this excellent work. Still we have 
always regarded Mr. Quekett's work as too minute and ex- 
tended, as well as too expensiv^e, to serve the purposes of those 
who only want an explanation of the insti'ument and a few 
plain directions for its use. The little work published in 
America by Dr. Wythes in size and price is evidently more 
adapted for general use. Its plan and contents are so evidently 
founded upon the work of Mr. Quekett that we wonder the 
author did not at once acknowledge how largely he is indebted 
to that gentleman's labours. It is one of the grievances that 
literary men have to complain of in this country, that their 
works are reprinted in America without their obtaining any 
profit fiom the wide sale they meet with in that country, and 
the least they have to expect is, when their works are reprinted 
or extensively drawn upon, that the debt be acknowledged. 

As an instance of how much Dr. Wythes is indebted to the 
English professor, we would quote the chapter on Test-objects, 
which is scarcely more than an abstract of the chapter on the 
same subject in Mr. Quekett's book, and in which no pains 
have been taken by an alteration of expression to conceal the 
source of the information. The plates illustrative of this sub- 
ject are also copied from Mr. Qu^'kott's work, as well as many 
others. 

Although Dr. Wytlies' work is intended for all who use 



THE MICKOSCOPIST. 53 

the microscope, it is very evident that his own acquaintance 
with this instrument has been ahnost exclusively confined to 
animal tissues. Thus, speaking of the " circulation in plants 
termed cyclosis^^ he says, " It can be observed in all plants 
in which the circulating fluid contains particles of a different 
refractive power or intensity, and the cellules are of sufficient 
size and transparency. Hence all lactescent plants, or those 
having a milky juice, with the other conditions, exhibit this 
phenomenon." He has here confounded the general move- 
ment of the sap witnessed in lactescent plants with cyclosis. 
Again, in a chapter somewhat singularly called the " cell- 
doctrine of physiology," in speaking of the development of 
cells within other cells, he says, " each granule of the nucleus 
has the power of developing a cell ;" and without any allusion 
to this as a controverted opinion, or to any other form of cell- 
development, he leaves the subject. It would perhaps be 
better in works of this kind that all physiological views and 
general principles arising out of the investigation of particular 
structures should be omitted. All that is required is a refer- 
ence to the various classes of objecis in which the microscope 
is found of advantage, and directions as to the best methods 
of examining such objects. In the present instance we find 
no directions given as to the best way of exhibiting t!ie cyto- 
blast or the objects best fitted for showing it. Another 
omission in this book of more importance is the entire absence 
of any allusion to the use of re-agents in the examination 
of animal and vegetable tissues. The aid of chemistry has 
become so important in distinguishing certain tissues under 
the microscope, that too much stress can hardly be laid upon 
it in any directions for its use. 

The work is illustrated with a great number of wood-cuts ; 
some of those of microscopic objects are very coarsely done. 
This is a pity, as too great pains cannot be taken in making 
evident in drawing those distinctions which are evident with 
the microscope. The wood-cuts, for instance, of the caudate 
cells, in figs. 36, 40, 41, and 42, are not sufficiently different 
to lead a young microscopist to the belief that by their means 
a distinction may be made out between an innocuous and a 
malignant tumour. We are sorry to have to find so much 
fault with this book, but it contains the elements of a useful 
volume, and, if we may judge from its sale in this country, 
the present edition is likely soon to be sold off, and to afford 
Dr. Wythes an opportunity of correcting its errors, acknow- 
ledging his debts, and extending his work in those directions 
in which it is most deficient. 



( 51 ) 



NOTES AND CORRESPONDENCE. 



New Methods of Constructing the thin Glass and 
BUILT Cells for Preserving Objects in Fluid. — In conse- 
quence of the difficulty of making the thin glass cells now in 
use, they are not so frequently employed by microscopists 
as they would be if their manufacture were more simple, 
and they could be obtained at less cost. One method of 
making these thin cells consists in grinding down a thick 
section of glass tube, or thick glass bottle, until the requisite 
tenuity has been obtained. This process is obviously quite as 
laborious as that of drilling through several squares of the thin 
glass cemented together by marine glue, and afterwards sepa- 
rating them for mounting on the glass slide. By either of 
these processes it is obviously difficult to obtain cells varying 
much in size, the usual dimensions of the cell being not more 
than half an inch in diameter ; and it is almost impossible to 
make large shallow glass cells by either of the above-mentioned 
methods. 

Method of viahing the thin Glass Cell. — Some time ago a 
very simple method of perforating the thin glass occurred to 
me, which has been found to answer exceedingly well, and it 
has this great advantage, that the microscopist can make cells 
for himself of almost any dimensions required. 

The principle of the process depends upon the fact that a 
crack will not extend across any part of a piece of thin glass 
which is fixed by marine glue to any firm surface to which it 
is capable of adhering. Ttie edges of the thin glass may be 
broken in all directions, but the crack will extend only up to 
the marine glue, and no farther. If a piece of thin glass be 
fixed by marine glue to one of the thick sections of tube used 
for making cells in which injections are mounted, and allowed 
to cool, a hole may be made in the centre with a file, which 
may then be carried round the edges, and a thin glass cell 
exactly the size of the thick one is produced. It is removed 
by heating the glass, and may tlien be transferred to a slide 
and fixed at once, or the glue adhering to it can easily be re- 
moved by soaking it for a short time in potash. The surfaces 
may be roughened, or the cell may be ground thinner by rub- 
l)ing it on a Hat surface with emery-powder in the usual way. 




MEMORANDA. 55 

All that is requisite, then, to make thin glass cells of any 
required form and dimensions, is to obtain a perfectly flat, 
thick ring, to which the glass may be cemented, and in a few 
minutes several thin cells of large size may be made, and at 
very trifling cost. 

It may not be out of place here to describe a very simple 
method of cutting the circular glass covers for thin glass cells. 
For this purpose several beautiful forms of apparatus have 
been devised ; amongst others may be mentioned that of Mr. 
Darker, by aid of which circles of any diameter may easily be 
cut. A very simple form of apparatus may be made by sol- 
dering on each side of 
several common brass cur- 
tain-rings a straight piece 
of wire, as in the figure, 
by means of which the 
ring can be held firmly 
by two fingers against 
the thin glass lying on a 
perfectly flat surface. The writing diamond is then carried 
round the inside of the ring, and the circular piece of glass 
is readily obtained. The rings may be purchased of any size, 
and by a little bending they may be formed into a very good 
oval for cutting thin glass of this form. 

Method of makiiiy the built Glass Cell. — The usual plan of 
constructing the deep glass cells, by joining together several 
slips of thick plate glass, the edges of which have been ground 
perfectly flat, and cementing them at the angles with marine 
glue, is a process of considerable labour. For some time past 
I have been endeavouring to devise a method by which these 
cells could be more readily made, as their advantage over 
bottles for mounting many preparations is obviously great. 
The process about to be detailed requires some practice, but, 
when this is acquired, cells may be made much more rapidly 
than by the old method,' and have the advantage of possessing 
fewer joins. 

A slip of plate glass, of the required depth, of about the 
eighth of an inch in thickness, and of sufficient length to make 
all four sides of the cell, is taken. The length of each side is 
to be accurately marked upon it with a spot of ink, and in 
these situations the glass is to be carefully and very gradually 
raised to a red heat in the blow-pipe flame, and then bent 
so as to form a good angle ; care being taken not to twist 
the glass in the slightest degree. The other angles are 
formed in the same manner, each being cooled as gradually 
as it was heated. Tlie ends are to be afterwards cemented 



56 MEMORANDA. 

together by heating- in the blow-pipe. If the last side when 
bent round should be found to be too long, a small portion can 
be cut off by aid of the ^diamond, and, with a little care in 
heating the ends and pressing the glass together when in a 
softened state by a small piece of wire, an excellent juncture 
may be made ; or, if preferred, the join may be effected in the 
centre of one of the sides. In this way cells may be made of 
half an inch in depth, or rather more, and of any requii'ed size. 
The great difficulty in constructing cells in this way arises 
from the glass cracking in the process of heating or cooling, 
and from the tendency of the sides to twist when the glass is 
softened in the position of the angles. The latter difficulty is 
soon overcome by practice ; the former would be avoided if, 
instead of the ordinary plate glass, flattened and well-annealed 
flint glass were employed ; and I believe that, with this mo- 
dification, the construction of cells would be much simplified, 
and they might be made at a cost far less than that for which 
built glass cells can now be obtained. When the angles are 
formed and the glass joined, the surfaces are ground flat in the 
usual way ; and if care be taken to prevent twisting, this part 
of the process is soon executed. After grinding they are fixed 
to a flat plate-glass slab with marine glue. I have succeeded 
in making several cells in this manner which have now bad 
preparations in them for upwards of two years. — Lionel S. 
Beale, M.B.— 27, Carey Street, Aug. 1852. 

Structure of the Epidermis of the Petal of the Geranium. 
— The petal of the Geranium is one of the most common and 
beautiful objects in microscopic cabinets. The usual way of 
preparing it is by immersing the leaf in sulphuric ether for a 
few seconds, allowing the fluid to evaporate, and then putting 
it up dry. Another is by simply drying the petal, immers- 
ing for an hour or two in spirits of turpentine, and then put- 
ting it up in new Canada balsam. 

By neither of these plans is the true structure shown ; we 
can recognise the mamillary process of each cell, but not the 
few hairs which surround their margin. 

The only way in which I have succeeded in preserving 
these is the following: — I first peel off the epidermis from 
tlie petal, which may readily be done by making an incision 
through it at the proximal end of the leaf, and then tearing it for- 
wards by the forceps. This is then arranged on a slip of glass, 
and allowed to dry ; when dry, it adheres to the glass ; place 
on it a little Canada balsam diluted with turpentine, and boil 
it for an instant over a spirit-lamp ; this blisters it, but does 
not remove tlie colour. Cover then witli a thin slip to pre- 
serve it. On examination many cells will be found showing 



MEMORANDA. 57 

the mammilla very distinctly and the score of hairs surrounding 
its base, each being slightly curved and pointing towards the 
apex of the mammilla. It is these hairs and the mammilla 
which give the velvetty appearance to the petal. — Thomas 
Inman, M.D. Liverpool. 

On the Formation of Dotted Tissue. — Bothrenchyma 
forms a very popular microscopic object. It is interesting 
to examine the way in which it may be formed. It may 
be produced, as in rhubarb, by the filling up of inter- 
spaces between fibres until a small pit only remains : or, 
as in the Alnus serratula, by a number of lines, arranged 
at first like those of a ladder, then united by transverse 
ones forming a grating, the angles being filled up and rounded 
last : or, as in the Populus tremuloides, by an uniform deposit 
over the whole membrane. It is generally known that 
bothrenchyma does not exist in coniferous wood, but in 
some varieties a dotted tissue may be distinctly made out, 
situated in the medullary rays. The wood in which I have 
found it is that of which eau de Cologne boxes are made. Its 
rudiments are to be found in common deal. The formation is 
readily accounted for. Wherever the two sets of fibres or cells 
cross each other, their angles are filled up, and they form 
appaiently a grating of round holes instead of square. They 
could never be mistaken for genuine bothrenchyma. 

I have heard many suggestions as to the use or intention of 
these little pits ; passing by the obvious one of their promoting 
the easy transmission of fluid, the following seems the most 
striking. They are intended to unite the utmost possible 
strength with the utmost possible lightness — e. g.^ if an en- 
gineer wanted to cast a pillar which should combine these two 
qualities, he would mould it on a plan precisely similar to a 
dotted duct. — Ibid, 

Optical Properties in a Salt of Quinine. — Dr. Hera- 
path, of Bristol, has recently described a salt of quinine, 
which has remarkable polarizing properties. The salt was 
first accidentally observed by Mr, Phelps, a pupil of Dr. 
Herap.ith's, in a bottle which contained a solution of disul- 
phate of quinine. The salt is best formed by dissolving disul- 
phate of quinine in concentrated acetic acid, then warming 
the solution, and dropping into it carefully, and by small 
quantities at a time, a spirituous solution of iodine. On 
placing this mixture aside for some hours, brilliant plates of 
the new salt will be formed. The crystals of this salt, when 
examined by reflected light, have a brilliant emerald green 
colour, wlti almost a metallic lustre ; they appear like portions 
of the elytra of cantharidcs, and are also very similar to mur- 



58 MEMORANDA/ 

exide in appearance. When examined by transmitted light 
they scarcely possess any colour — there is only a slightly olive- 
green tinge ; but if two crystals, crossing at right angles, be 
examined, the spot where they intersect appears as black as 
midnight, even if the crystals are not l-500th of an inch in 
thickness. If the light be in the slightest degree polarized — 
as by reflection from a cloud, or by the blue sky, or from the 
glass surface of the mirror of the microscope placed at the 
polarising angle 56° 45' — these little prisms immediately 
assume complementary colours : one appears green, and the 
other pink, and the part at which they cross is a chocolate or 
deep chestnut brown, instead of black. As the result of a 
series of very elaborate experiments. Dr. Herapath finds that 
this salt possesses the properties of tourmaline in a very 
exalted degree, as well as of a plate of selenite, so that it 
combines the properties of polarizing a ray and also of depolar- 
izing it. Dr. Herapath states, in his last communication to 
the ' Pharmaceutical Journal ' on this subject, that he has suc- 
ceeded in making an artificial tourmaline large enough to 
surmount the eye-piece of the microscope, so that all experi- 
ments with those crystals upon polarized light may be made 
without the tourmaline or Nicholls prism. He says that the 
brilliancy of the colours is much more intense with the 
artificial crystals than when employing the natural tourmaline. 
As an analyser above the eye-piece, it offers some advantages 
over the Nicholls prism in the same position, as it gives a 
perfectly uniform tint of colour over a much more extensive 
field than can be had with the prism. 

Desquamation of Pulmonary Air-Cells. — Attention has 
recently been called to the value of the microscope in diseases 
of the kidney. It has frequently been appealed to in diseases 
of the lungs, but with less success. My intention is to show 
that in some rare cases some similarity may be found micro- 
scopically between the one and the other. 

Dr. G. Johnson has pointed out how constantly one form 
of inflammation of the kidney shows itself by epithelial de- 
squamation, and how generally the casts of the urinary tubes so 
produced may be found in the urine. 

I have on one occasion discovered the traces of a similar 
process in the lungs. A friend forwarded me some expectora- 
tion from a patient, with a request that I would examine it, 
and give an opinion, if I could, whether the case was one of 
plitliisis or bronchitis, a question her attendants were unable 
to solve. As tlie examination was somewhat instructive, I 
will give its detail. Tlie first specimen I examined con- 
tained abundance of pus and mucous granules, a number of oil 



MEMORANDA. 59 

pflobules, and some scattered particles of starch. There was 
also a fragment or two of fibrous tissue, which might or might 
not be a portion of broken-down lung. 1 soon succeeded in 
obtaining larger specimens of this, and found it was a cell- 
stiucture too regular for any in the animal world. By char- 
ring, it gave a vegetable smell, and reminded me of burnt 
bread. I then procured some bran, and found that it re- 
sembled it closely. The first diagnosis was then, that the 
patient had been eating bread and butter. I next took some 
of the sputa and agitated them with water for a considerable 
time, boiling at last to dissolve the mucus completely. After 
a time a white sediment appeared at the bottom of the vessel, 
consisting of very minute granular particles. These, when 
examined under the microscope, were found to be accumula- 
tions of epithelial cells, arranged in a hollow globular form, 
and measuring about l-500th of an inch in diameter. Most 
of them were single, and had a small entrance tunnel some- 
times opening into a fragment of a larger tube. They re- 
sembled very closely a roughly-cast bullet before it has been 
trimmed. Here and there others were found in small masses, 
like a diminutive bunch of grapes. The rest of the deposit was 
made up of amorphous granular membrane, and seemed as if 
it had come from a large cavity, I considered that the evi- 
dence was scarcely sufficient to enable any decided opinion to 
be given ; for it was not absolutely certain (however probable 
it was) that these casts of cells came from the lungs, and, if 
they did, whether they indicated simple inflammation or 
tubercular disease. The woman suffered much from relaxa- 
tion of the soft palate, and the cells might be from its mucous 
glands. 

The patient died shortly after, and no examination was 
allowed. 

The results of this case induced me to examine others of 
confirmed phthisis, but in one instance only have I been able 
to find a similar appearance. The most common phenomenon 
is that of a brownish amorphous membrane, of variable size 
and shape, studded with oil globules and small nuclei, and 
which seems to be the secretion from a diseased surface, and 
analogous in a small degree with the amorphous casts found 
in chronic desquamative nephritis. As these membraniform 
bodies evidently come from large cavities, and have not been 
found in those specimens of simple bronchitis that I have 
examined, their occurrence in the sputa may probably form a 
diagnostic sign Ijetween it and phthisis. My observations 
have not as yet been sufficiently extended to enable me to 
declare positively that they are diagnostic. I would only add, 



60 MEMORANDA. 

as a sort of apology for my first diagnosis, the following anec- 
dote : — A microscopic friend, while examining the sputa of 
a phthisical patient, detected in it a number of muscular fibres 
exhibiting the striae more beautifully than in any preparation 
he had ever seen. After a long consideration of the case and 
consultation with another, he came to the conclusion that there 
was ulceration of some parts of the larynx with loss of mus- 
cular substance. It was not for some time after that he ascer- 
tained that the sputa were taken after dinner, that the patient 
had had meat, and that the fibres were due to a slaughtered 
ox, and not to a human larynx, — T Inman, M.D, Liverpool. 

The Miscroscope as a Test of the Purity of Drinking 
Waters. — In the examination of waters supplied by nature for 
dietetical and economical purposes, a chemical examination of 
their contents has been usually deemed sufficient in order to 
ascertain their qualities. It is, however, evident that, how- 
ever accurately chemistry might be able to pronounce on the 
quantity of the organic contents of waters, the qualities of 
these matters can only be ascertained by means of the Micro- 
scope. We are indeljted to Dr. Hassall for first taking up 
this subject ; and during the last Session of Parliament Dr. 
Lankester and Dr. Redfern were examined before the Com- 
mittee of the House of Commons, on the water supply of the 
Metropolis, with reference to the Microscopic contents of the 
Tliames and other waters. A report has been drawn up by 
these gentlemen at the request of the London (Watford) Spring 
Water Company, in which they give the results of their 
examination of waters supplied from the Thames, the New 
River, the Surrey Sand Springs, the river Dee, and water from 
wells at Watford. The mode of proceeding was, to take half 
a gallon of the water to be examined, and, after allowing it to 
stand for a few hours, to decant the clear liquid from above 
till about half an ounce remained. A drop of tlds was taken 
up by a pipette and examined under the Microscope. It would 
appear from these reports that, in proportion to the absence of 
inorganic and organic matters in a state of decomposition, is the 
water free from microscopic plants and animals. Great differ- 
ences in these respects are presented by the water examined. 
Thus, i.i the river Dee and the Watford water, scarcely a 
living organism was found, whilst in the Thames and New 
River waters above seventy species have been identified by 
the reporters. 



( ♦>! ) 



PROCEEDINGS OF SOCIETIES. 



Microscopical Society of London. Session 1852. 

January 28, — Dr. Arthur Farre in the Chair. On the structure 
of the Raphides of Cactus enneagonus, by Professor Quekett. 

February 18. — Anniversary Meeting. 

March 17. — George Jackson, Esq., in the Chair. Hints on 
tlie subject of collecting Objects for Microscopical Examination, by 
George Shad bolt, Ksq. 

April 28. — George Jackson, Esq., in the Chair. On a Cyst, 
containing a large crystal of oxalate of lime, found upon the olfac- 
tory nerve of a horse, by James B. Simonds, Esq. 

May 26. — George Jackson, Esq., in the Chair. On the develop- 
ment of Tubularia indivisa, by J. B. Mummery, Esq. 

On the structure and development of Volvox globator, by George 
Bush, Esq., F.R.S 

Jfine 23. — George Jackson, Esq., in the Chair. On the Anatomy 
of Volvox globator, by Professor W. C. Williamson. 

British Association for the Advancement op Science. 

Belfast Meeting, September 1852. — In the Mathematical Sec- 
tion Sir David Brevrster gave an account of a Rock Crystal Lens, 
which had been found in the treasure-house in the ruins of Nineveh. 
The lens vi^as not entirely circular in its aperture, being 1 6-lOths 
of an inch in its longer diameter and 1 4-lOths in its shorter. 
Its general form was that of a plano-concave lens, the plane side 
having been formed of one of the original faces of the six-sided 
crystal of quartz. The convex face of the lens was unequally thick, 
but its extreme thickness was 2-lOths of an inch, its focal length 
being 4i inches. It had twelve remains of cavities, which had 
originally contained liquids or condensed gases ; but ten of these 
had been opened, probably in the rough handling which it received 
in the act of being ground. 

Professor Stokes read a paper on the Optical Properties of the 
Salt of Quinine, discovered by Dr. Herapath (p. 59). He ex- 
plained the remarkable properties possessed by this salt according 
to the undulatory theory. The reflecting properties of these crys- 
tals, he stated, might be embraced in one by regarding the medium 
as not only doubly refracting and doubly absorbing, but doubly 
metallic. The principal object of the paper was to point out the 
intimate connexion which exists between the coloured reflection, 
the double absorption, and the metallic properties of the medium. 

In the Natural History Section Professor Allman read a paper on 
the signification of the ovigerous vesicles in the Ilydroid polyps. He 
stated that the structure of these vesicles was the same as that of 



62 PROCEEDINGS OF SOCIETIES. 

the naked-eyed medusae. From repeated observations, he liad come 
to the conclusion that the ordinary polypoid structure is not sufficient 
for the production of ova, and that for these bodies a medusoid struc- 
ture is always necessary, whether it be obvious as in the free gem- 
mae, or disguised as in the fixed ovisacs. 

The Rev. T. Hincks read a paper, in which he pointed out certain 
peculiarities in the structure of some of the marine Bryozoa, which 
led him to the conclusion that there existed in these animals a dif- 
ference of sex. 

Mr. Wyville Thomson read a paper on the specific characters of 
some of the Sertularian zoophytes. He endeavoured to point out 
the fallacy of using the ovigerous vesicles as means of specific dis- 
tinction in this class of animals, and observed that forms of the 
same species had been separated by relying on tlie characters afforded 
by these organs. 

Professor Allman made a communication on the presence of a 
form of fermentation-fungus in the fluid of the warm water flax- 
steeps. After the flax has been in the water a few hours, the water, 
on being submitted to the microscope, presented numerous minute 
graimles, which moved about by the aid of a moving cilium. 
Sometimes two of these bodies were attached at each end of the 
cilium. They ultimately became converted into cells, which pro- 
duced smaller cells upon their surface, eventually assuming the 
form of a moniliform alga. 

Professor Allman likewise described a minute alga, which had 
coloured green large masses of water. It was in the form of little 
conglomerated gelatinous masses, consisting of numerous fronds. 
The fronds were nearly spherical, and consisted of a central mass of 
transparent gelatinous matter surrounded by an outer coating of 
minute cells of a green colour. The external crust bursts, and allows 
the gelatinous nucleus to escape, whicli then separates into two dis- 
tinct fronds by a process of contraction. 

A paper was read from Professor Wharton Jones on the forces 
by which the circulation of the blood is carried on. In this paper 
reference was made to a discovery announced by the author, in a 
paper read before the Royal Society on the 5th of February, 1852. 
This discovery consists in the fact of a rhythmical contraction ex- 
isting in the walls of the veins of the bat's wing. These veins are 
supplied with valves which prevent the regurgitation of the blood ; 
and the author suggests that this contractility of the veins is a pro- 
vision for securing the return of the blood to the right side of the 
heart. The author could not discover this contractility in the ear 
of the bat, nor in the mesentery of a mouse. 



( «^3 ) 



DESCRIPTION OF PLATE I. 

On Actiuophrys Sol, hy Professor Kolliker. 

Fig. 1. — Apparent transverse section oi Actinophrys Sol, drawn so that the 
parts visible in indistinct ontline are not indicated. The structure ex- 
hibited in this figure is afforded by Actinophrys in any plane passing 
through the centre, o, cortex : h, nucleus of the animalcule ; c, 
homogeneous basal substance ; in the nucleus with numerous granules ; 
d, hollow spaces, ' Vacuoles,' filled with a clear fluid ; e, tentacular 
filaments. 

Fig. 2. — The same, less highly magnified, at the moment of feeding. 
a — e as above;/, an Infusorium, which has just entered the sub- 
stance of the body, whilst the surrounding filaments enclose it on all 
sides ; g, a spore of an Alga alread}' nearly engulphed in the cortical 
substance ; the depression in which it is contained, however, is still 
open to the exterior, the filaments are again nearly erect ; h, a spore 
of Vaucheria, lying in a hollow space of the nuclear substance. 

Fig. 3. — A somewhat more highly magnified Actinophrys, with very short 
just-sprouting tentacular filaments. a — e, as in fig. 1 ; /, a Vau- 
cheria spore, wholly imbedded in the cortical substance, the opening 
through which it entered entirely closed, although its situation is 
indicated by a slight depression ; g, another spore, already entering 
the nuclear substance ; h, an Infusorium lying in a special cavity ; 
i, a spore in the nuclear substance ; h, half-digested morsels ; I, a 
swallowed I.ynceus ; m, excrementitious matter in the form of a 
spherical, clear droj"*, with granules, beginning its exit from the 
cortical substance. A portion of it is already protruded from an 
oi)ening, the margin of which is fringed. 

Fig. 4, — A smaller portion of the border of an Actinophrys, magnified 450 
diameters, a, c, d, e, as in fig. 1 ; /, sprouting, conical, tentacular 
filaments ; g, one a little longer ; h, enlargement upon a developed 
but not extended filament. 

Fig. 5. — A portion of the nuclear substance, magnified to the same extent, 
c, d, e, as before ; /, nucleus in one of the hollow spaces ; g, a cell ? 
from another hollow space, isolated. 

Fig. 6. — A true anastomosis of three striped muscular fasciculi from the 
auricle of the frog. a, sarco lemma; b, fibrillaj, with transverse 
stripes. 



On the Contractile Tissue of the Iris, by Joseph Lister, Esq. 

Figs. 7, 8, 9, 10, 11. Muscular fibre-cells of the human iris. 
Fig. 12. — Nucleus from the sphincter pupillae of a horse. 

13. — Muscular fibre-cells from the edge of the pupillary margin of the 



64 DESCRIPTION OF PLATE I. 



Anatomy of Melicerta ringens, hy Professor Williamson. 

Fig. 14. — Animal of Melicerta ringens removed from its case. 
15. — One of the tentacles (Fig. 14 d) fully expanded. 
16. — The same, with the seta^ drawn inwards. 
17. — Dental apparatus (Fig. 14 e) more fully magnified. 
18. — One of the ciliated epithelial cells from the upper stomach. 
19. — Lower part of the visceral cavity, and upper part of the caudal 
i:)rolongation, more fully magnified. 

20. — Extremity of the caudal prolongation expanded into a disc. 
21. — Muscular fasciculi, invested with their sarcolemma in a state of 
conjugation. 

22. — Ditto, with the sarcolemma stretched out. 
23. — One of the nuclei of the ovary with its nucleolus. 

24. —The nucleus, as removed from a fully-formed ovum. The nu- 
cleolus absorbed. 

25, 26, 27, 28, 29. Ova in various states of develojiment. 
30. The animal of Fig. 29 just liberated from the ovum, 
31. — The same animal in motion. 

32. The young animal affixed to a leaf, and commencing the con- 
struction of its external case, 
33, — Portion of the case at its lower extremity. 
34. — The same at its upper extremity. 



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T.ACINULARIA 



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A LACINULARTA. B 1\/IELICERTA. C BRACHIONUS. 



DESCRIPTION OF THE PLATES. 

The letters tbrougliout liave tlie same signification : — a, trochal disc ; 
h, body ; c, tail of peduncle ; d, mouth ; e, pharynx ; /, " yellow mass ;" 
g, gizzard ; /;, " pancreatic sacs ;" /, rectum ; k, anus ; I, ovary ; m, 
water- vessels ; n, ganglion ; o, ciliated sac ; p, upper circlet of cilia ; p', 
lower circlet of cilia ; r, vacuolar thickenings. 



PLATE I. — Lacinularia sociah's. 

Fig. 

1. A single individual from the side. 

2. Lateral view of the trochal disc. 

3. Trochal disc from above. 

4. Aperture of the mouth — ciliated sac and ganglion. 

5. Animal retracted. 

6. Armature of the gizzard, viewed laterally. 

7. Termination of a water-vessel in the trochal disc. 

8. Water-vessel much magnified, showing the long flickering cilium. 

9. A portion of the ovary much magnified, showing the germinal vesicles 

with their spots scattered through its substance. 
10, 11. Stages in the growth of the ovum. 
12-18. Stages in the development of the embryo. 

19. Spermatozoon.? 

PLATE 11. 

20. A portion of the ovary undergoing the change into an ephippial ovum. 

21. 22. Ephippial ova, the latter having its contents divided into two 

portions. 

23. Ejihippial ovum burst. 

24. Its contents. 

25. Muscular fibre — relaxed, a ; contracted, b. 



Melicerta ringens, 

26. Viewed laterally. 

27. From the ganglionic side. 

28. From the mouth side. 

29. Extremity of the calcar, showing its apparent closure and (lie bundle 

of cilia. 

Brachionus 2)oIyacanthv.s. 

30. Viewed laterally. 

31. From the mouth side. 

32. From the ganglionic side. 

33. From above. 



Philodina, sp. ? 



34. Trochal disc from above. 

35. laterally. 

36. From the mouth side. 

37. P'rom the ganglionic side. 



PLATE III. 

The Diagrams of Adult Rotifera, and of Larval Annelids and Echino- 
derms, illustrate Mr. Huxley's paper on Lacinularia. 

Fig. 

1, Raphides from Cactus enneagonus, showing a nucleus surrounded by 

concentric laminas. 

2. The same, vnth irregular lamina?. 

3 & 4. The same, without concentric lamination. 

5. Xuclei of raphides. 

6. Separated crystals of compoiind raphides. 



S^Jf^uyr-Sfac/J^IJT 



■Rotlfero 




.Azmelids 
A Eckm-odenas. 




JLacz.niiZaricL. MJelusrta^ 



Phjdodzna, Bra.chxon3Ls Stephuwceros 








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a.Al^st.'&ap ^t.anoB.Qu4«. 



( 65 ) 
ORIGINAL COMMUNICATIONS. 



On the Anatomy of Melicerta ringens. By Professor 
W, C. Williamson. 

[Continued from page 8.] 

The most interesting portion of the history of Melicerta is 
connected with the development of its ova, which process the 
transparency of its organs enables us to watch with facility. 
I have already described the position of the ovary and oviduct. 
The ovary is a hollow sac consisting of a very thin pellucid 
membrane. It is filled with a viscid granular protoplasm of 
a light grey colour, in which are distributed from twenty to 
thirty nuclei (23), each having a diameter of from 1-1 200th 
to 1-i 600th of an inch. Each nucleus contains a large nu- 
cleolus varying in diameter from l-1600th to 1 -3500th. In 
its normal state, the granular protoplasm is of an uniform grey 
colour, flowing freely out of the ovary when the latter is rup- 
tured. The nuclei situated near the centre of the ovary appear 
to be successively selected for development. One of these nearest 
the surface attracts round it a small portion of the granular pro- 
toplasm, detaching it from the remaining contents of the organ, 
though still in close contact with them. The portion thus 
specially isolated gradually enlarges, assuming at the same time 
a darker hue, whilst, from its central position, it partially divides 
the upper from the lower half of the remaining ovarian proto- 
plasm. At the same time the central nucleus sometimes 
undergoes some slight enlargement, and its nucleolus appears 
to become absorbed ; the position of this nucleus in the centre 
of the ovum is now indicated by an ill -defined transparent 
spot ; but on bursting the protoplasmic mass it is seen to be 
a small spherical cell (26) about 1- 1000th of an inch in 
diameter, having very thin pellucid walls, and scarcely any 
visible cell-contents. When the ovum thus segmented from 
the ovarian protoplasm has attained its full size (14 q\ it 
becomes invested by a thin shell, which is apparently a secre- 
tion from its own surface. This view of its origin is of course 
difficult to prove, but I have sought in vain for evidence that 
it could have been formed in any other way. 

The ovum being now ready for expulsion, it is slowly forced 
down to the lower part of the ovary, the stomachs being drawn 
upwards and to one side in oi'der to make way for it. Yield- 
ing to the pressure produced by the successive contractions of 
the body, the ovum sweeps round the inferior border of the 

VOL. I. F 



66. ON THE ANATOMY OF MELICERTA RINGENS. 

lower stomach, and, passing tlirough the dilated oviduct, enters 
the cloaca. The latter canal becomes entirely everted, as is 
the case when the excrements are discharged, and by a sudden 
contraction the ovum is expelled. 

At this stage of its development the egg has an average 
length of 1-1 50th of an inch, and a diameter of 1-2 50th. Its 
yolk usually consists of a single segment (14^ and 25), there 
being a small space at each extremity of the egg which the yolk 
does not occupy. Very soon, the central nucleus becomes drawn 
out and subdivides into two, this division bring followed by 
a corresponding segmentation of the yolk (26). The same 
process is repeated again and again (27), until at length the 
entire yolk is converted into a mass of minute cells (28). 
The first trace of further organization which presents itself 
appears in the form of a few freely moving ciliae. These pre- 
sent themselves at two points, one at 28 a, which corresponds 
with the future head, and the other near the centre of the 
ovum (28 b), which is destined to become the cavity of the 
stomach : shortly after this appearance of cilia^, traces of the 
central parts of the dental apparatus present themselves, this 
again being soon succeeded Ijy the unicni of the entire mass of 
yolk-cells, and the formation from them of the various organs of 
the animal (29). The ciliae now play very freely, especially 
at the head (29 a). The creature twists itself about in its 
shell ; two red spots (29 6) appear near the head, which 
Ehrenberg regards as organs of vision, and along with them a 
very dark brown and somewhat larger spot is developed in the 
integument near the lower stomach. The young animal now 
bursts its shell, and, on first emerging, presents the appear- 
ance of fig. 30 ; the two hooks are formed (30 a) as well as 
rudiments of the two tentacles (30 b), and the whole of its 
internal organization, though but obscurely seen, is neverthe- 
less that of the perfect animal, and not that of a larval state. 

Almost immediately after its escape from the egg, the 
young Melicerta stretches itself out, and everting the anterior 
part of its body unfolds several small projecting mamilla? 
covered with large cilia?, by means of which it floats freely 
away. Its present form is seen in fig. 31. The ciliated 
mamillfie (31a) at this stage of growth are not unlike those 
seen in Notammataclavulata, but they soon enlarge and become 
developed into the flabelliform wheel-organs of the matured 
animal. The dental apparatus (31 b) is now fully developed ; 
the alimentary canal and muscular fasciculi are all present, 
only the epithelial cells of the former have not as yet ob- 
tained their yellow granular contents, consequently the viscera 
exhibit the same hyaline aspect as the rest of the organism. 



ON THE ANATOMY OF MELICERTA RINGEN8. 67 

The two red specks (3i c) are imbedded in two of the 
inammillap. 

After swimming; about for some time, like other free Roti- 
fera, the animal undergoes further changes. The dark brown 
spot (31 d) is the first to disappear, and soon afterwards the 
two pink ones (31 c) cease to be visible. The animal attaches 
itself by the tail to some fixed support, and developes from 
the skin of the posterior portion of its body a thin hyaline 
cylinder, the dilated extremity of which is attached to the 
supporting object. This structure has been already noticed 
by Dr. Man tell (Thoughts on Animalcules), though I have 
never seen it so largely developed as is represented in his 
figures. The young animal, having chosen a permanent rest- 
ing-place, commences the formation of its singular investing 
case. I have verified Dr. Mantell's account of the position 
occupied by the first-formed spheres. They are arranged 
in a ring round the middle of the body, and are for some 
time unattached to the leaf or stem which supports the 
animal. They appear to have some internal connection 
with the thin membraneous cylinder (32 a). At first, new 
additions are made to both extremities of the enlarging ring. 
But the jerking contractions of the animal at length force 
the caudal end of the cylinder down upon the leaf, to which 
it becomes securely cemented by the same viscous secretion 
as causes the little spheres to cohere. All the new additions 
are now made to the free extremity, which, as Ehrenberg 
remarks, never extends beyond the level of the cloacal aper- 
ture of the outstretched animal. At its attached base, the 
cylinder consists of closely fitting hexagons (33) 1-1 600th 
of an inch in diameter; but as we approach the opposite 
extremity, they become perfect spheres (34) (1- 1100th of 
an inch in diameter), each one touching six surrounding ones, 
by six corresponding peripheral points. Small triangular 
spaces intervene, occupied only by the transparent secretion 
which glues the little spheres together. The fully-matured 
animal maintains its position within this case by means of its 
caudal prolongation, the extremity of which can be more or 
less flattened out into a suctorial disc (20 c). 

From the above description it will be seen that the Melicerta 
ringens, one of the most highly organised of the Rotifera, does 
not pass through any larval form, in which it is represented 
by some of the simpler polygastric Infusoria. Though its 
external appendages, and especially the rotatory organs, are 
imperfectly developed at its birth, the organization as a whole 
is complete and final. The parts are all present, and only 
require to be expanded by the ordinary process of growth. 

f2 



68 ON THE ANATOMY OF MELICERTA RTNGENS. 

We have no metamorphosis such as is common among-st the 
Articulata : I have not even seen any evidence tliat the creature 
casts its skin. This fact was noticed by Dutrochet, and his 
observation appears to be correct. 

When the ova are discharged from the cloaca they succes- 
sively fall into the cavity of the tessellated case, where they 
undergo their further development. I have often found as 
many as four in one case, in the various stages of progress 
represented by figs. 12 to 16. It is whilst the eggs are thus 
protected that the young animals burst their shells — swim- 
ming out at the free extremity of the case as soon as they are 
liberated. When the ovum escapes from the cloaca its yolk 
usually consists of a single segment. In one instance only it 
had divided into eight whilst within the ovary. A second 
ovum is frequently seen progressing towards development 
whilst a fully shelled one is retained in the ovarium. Re- 
specting the process of fertilization we know nothing. The 
two tubes which I have referred to as being possibly spermatic 
ducts are the homologues of similar ones in other Rotifera, to 
which Ehrenberg has assigned fertilizing functions. Meli- 
cerfa ringens countenances his opinion on this point, though it 
does not prove it. I liave seen nothing resembling spermatozoa. 

In the possession of so highly organised a form of voluntary 
muscle, intlie investment of the fasciculi by a sarcolemma, and 
in the existence of a well defined ciliated cellular epithelium 
lining the alimentary canal, we have indications of an organiza- 
tion approaching that of the lower Articulata. The dental 
apparatus appears to constitute a splanchno-skeleton like that 
of the Crustacea ; but, on the other hand, the absence of a 
visil^le nervous system removes the Melicericc far below the 
Homogangliate animals. That they should possess a nervous 
system of some kind appears almost a matter of necessity, if 
the presence of striated muscular filjre indicates volition ; but 
its actual existence has yet to lie demonstrated. 

I have found no special organs of circulation or respiration. 
On watching the movements of the small free cells which float 
in the visceral cavity, as well as in the tail (14p), it becomes 
obvious that the fluid contained within the integument moves 
freely with every contraction of the body. I detect no vessels 
or pulsating organs. These facts also tend to associate the 
animal with the lower Nematoneura, if not even with the 
Acrita, rather than with the Homogangliate Crustaceans. At 
the same time its organization is of a higher type than that of 
the Bryozoa. 

Any attempt to establish the existence of hcmiologies between 
the phenomena attending the development of the ova in the 



ON THE ANATOMY OF MELTCERTA RINGENS. 69 

Melicerta and those of tlie liigber Mammalia may be deemed 
l^remature and unwise. Nevertheless there are some points 
in which a close relationshij) appears to be displayed. These 
affinities will be best traced by proceeding backwards from a 
stand-point wliere the homology is clear and definite. Tlie 
yolk of the matured egg of Melicerta is the obvious homologue 
of the yolk of the Mammalian ovum. Tlie circumstance that 
the entire yolk of the former enters directly into the composi- 
tion of the young embryo, by a process of segmentation, instead 
of imlircctlij and through the medium of a germinal membrane, 
does not materially affect the case. Tlie granular yolk of the 
Melicerta still corresponds with some early states of the granular 
yolk of the Mammalian ovum In tlie latter case each Graafian 
vesicle is filled with granules, along with some nuclei, float- 
ing in a colourless fluid. Amidst these, the germinal vesicle, 
with its contained nucleus or germinal spot, is developed. 
After a while some of the granules and a portion of the fluid 
in which they float are attracted around the germinal vesicle, 
and thus form the yolk. All this corresponds with what takes 
place in Melicerta. The entire sac of the ovary in the latter 
resembles a large compound Graafian vesicle distended with 
fluid, in which there float numerous granules, as well as 
twenty or thirty nucleolated vesicles, or nuclei ; each of these 
nuclei successively attracts around itself a portion of the gra- 
nular fluid to form the granular yolk, and the thickened shell 
may perhaps be regarded as the vitelline membrane, though 
this latter idea is not free from some objections. BischofF has 
observed that, as the Mammalian ovum advances towards ma- 
turity, the number of the granules increases, and hence the 
yolk is more opaque in the mature, and more transparent in 
the immature ovum. This is precisely identical with the 
changes undergone by the yolk of the Melicerta^ as described 
in the preceding pages. We may conclude from this com- 
parison, that the elements which are contained in and solely 
occupy the ovisac of the Melicerta., are those which in the 
ovaries of the higher mammalia are restricted to the interiors 
of the Graafian vesicles ; that whilst in the former case the 
protoplasmic stock forms one undivided mass, from which 
portions are successively pinched off to form the ova, in the 
latter examples it is divided into small portions, each being 
contained within a special receptacle, or Graafian vesicle ; the 
interspaces being occupied by the stroma or tissue of the 
ovary. 

Since recording the preceding observations, I have had the 
advantage of perusing Mr. Huxley's instructive paper on 



70 ON THE ANATOMY OF MELICERTA RINGENS. 

Lacinularia. I have verified Mr. Huxley's observation of 
the existence of tivo circlets of cilia, fringing the double mar- 
gins of the sinuated wheel-organs ; one being larger than the 
other. The larger one passes round the fissure dividing the two 
larger lobes, and consequently above the mouth. The smaller 
one, which is most external, passes below the mouth, being con- 
tinuous with the cili2e which fringe the " chin " of Mr. Gosse, 
the " fifth wheel-organ " of the preceding memoir. The food 
that reaches the mouth is whirled round the wheel-organs 
along the groove that separates the two circlets of cilia ; and 
since these circlets diverge near the " chin," the mouth being 
located between them, the food is necessarily conveyed di- 
rectly to the latter organ. The two sets of marginal cilia, 
by bending towards each other whilst in motion, almost con- 
vert this gi-oove into a sinus, especially in the two larger 
segments. I had previously noticed the outline formed by 
the outer and smaller of these margins, but regarded it as 
merely a thickened portion of the disk, to the surface of 
which I erroneously imagined these additional cilia to be 
attached. On each side of the oral aperture there project two 
small flattened lobes with ciliated margins, continuous with 
those of the chin, and which obviously assist in directing the 
food into the oesophagus. 

Between the mouth and the oesophageal bulb, on the same 
side as the ovary, is the transparent ball of horn-like sub- 
stance referred to by Mr. Huxley ; within the oesophagus, near 
its junction with the pharyngeal bulb, the ciliated lining mem- 
brane appears to hang in several loose, vibratile, longitudinal 
folds. I do not feel satisfied respecting the functions of the 
" nervous ganglion " of Mr. Huxley. I see no sufficient rea- 
sons for assigning to the small organ in question nervous 
functions. • Of the ciliated sac of Mr. Gosse I have obtained 
some faint glimpses, not having been so fortunate as to see 
the animal when engaged in its architectural occupations ; when 
not so engaged the sac becomes so contracted as to be almost 
invisible. 

Tlie singular bodies resembling spermatozoa exist in various 
parts of the organism, where they are apparently enclosed 
within hollow canals. I have never seen them occupying the 
two main trunks of the " water vascular system," or caeca, nor 
can I succeed in tracing any connexion between them. In 
several cases I have seen one or two of these curious bodies 
opposite the centre of the upj)er stomach, very near to, but 
independent of, the main c.rcal canal, and at some distance 
below the jjoint where tlie hitter probably subdivides into 
branches. Near the neck there arc usually from two to three 



GOSSE ON THE MELICERTA RINGENS. 71 

pairs. Their vibratile motion ceases the moment the animal 
is killed by pressure. This fact does not countenance the 
idea that they are spermatozoa. 

Two or three pyriform glandular (?) looking bodies are 
often attached to the base of the upper stomach, near the con- 
striction which separates it from the lower one. Similar but 
larger bodies are seen in the neighbourhood of the oesophagus. 
Not having been able to trace any ducts or orifices passing 
from these organs to the viscera, I have hesitated to assert 
their glandular character. 

In one example of Melicerta, the membranous ovisac was 
contracted and empty, containing neither protoplasm nor nuclei. 
Is this accidental, or may it have been a male animal ? 



On the Structure^ Functions, Habits, and Development of 
Melicerta ringens. By P. H. Gosse, A.L.S. 

By the courtesy of Mr. Matthew Marshall I was favoured, on 
the 27th of May, 1851, with some fragments oi Lemna trisulca^ 
and other aquatic weeds, from a large glass jar, swarming 
with Melicerta to such an extent that sixty or seventy are 
crowded on a single leaf. They are very distinctly ap- 
preciable to the naked eye, for many of the tubes are l-24th 
of an inch long, and when the animals are expanded, they 
reach to about l-20th of an inch. They are set on both 
surfaces of the leaves. The tubes contain about thirty-two 
rows of pellets ; each pellet is suiTounded by six others ; 
the rows are straight and uninterrupted perpendicularly, but 
transversely they are zigzagged, and the regular course is dia- 
gonal. Each pellet, examined separately, is of a yellowish or 
olive colour, composed of granules, and rather oval than round: 
the whole tube is of a reddish-brown. In old ones the surface 
is studded with Conferva;, Diatomacea, Podophryce, and other 
extraneous matters, even to the summit. By picking to pieces 
the tube with the points of needles under a small microscope, 
I can readily extract the animal ; it is often hurt by the pro- 
cess, but generally it is sufficiently whole to display the organ- 
ization. Fig. 12, plate II., is one so extracted. The tubes or 
spurs on each side of the head below the chin are evidently 
consimilar with the antenna? of Rotifer, &c. There is a slender 
piston in each, capable of being retracted and protruded, and 
bearing at its extremity a tuft of very fine, divergent, motion- 
U'ss hairs. 

The jaws arc very complex, and differ so much in different 
aspects, that they arc difficult to understand. Viewed in situ 



72 GOSSE ON THE MELICEKTA RINGENS. 

their appearance is as at fig. 1 6, or that of a single one examined 
carefully, as at fig. 17 ; but, under pressure, they become turned 
half-round, and appear as at figs. 18 and 19. In figs. 20 and 
2 1 these two aspects are recont iled, the corresponding parts 
being lettered alike, according to my belief. Tlie oblique pro- 
jection {d) appears conspicuous in a side view, as shown in 
situ in fig. 20. These parts are enclosed each in a globose 
transparent muscle (?), by whose action the form is much al- 
tered ; the points of the teeth (a) are drawn forward and down- 
waid, or vice versa, and the part lb) seems to be lengthened and 
variously modified in form. A filmy line, more or less obvious, 
connects the point h (in fig. 20) wit!i its fellow in the opposite 
jaw in some unintelligible way (see fig. 16). The action is not 
exactly that of two flat-surfaced mullers working on each other 
in a grinding manner, but a complex moticm, impossible to 
be explained l^y words. Below the two globose lobes there is 
another rounded lobe (see figs. 16 and 18) equally hyaline, and 
probably muscular, which seems united to the two others, and 
alters in form as they and the jaws work, lengthening down- 
ward as they approach, and dilating and shortening as they re- 
cede. A slender a'sophagus leads down to the gizzard, through 
whose lower part water is continually percolating, as it appears ; 
but perhaps the appearance is caused by ciliary waves. Below 
the gizzard extends a long, wide cylindrical stomach ; it ap- 
parently embraces the gizzard at its base without an appre- 
ciable tube ; a large globose gland (see fig. 12) is pi'obably one 
of a pair of pancreatic glands. The walls of the stomach are 
thick, and the food is received into a central tube, whence it 
passes into a globose intestine, the interior of which is covered 
with minute cilia. From the lower part of this viscus a slender 
but dilatable rectum turns up, and proceeds forward toward 
the occiput, till it terminates on the dorsal surface, just below 
the level of the gizzard. The cloacal outlet is capable of being 
greatly protruded, and this takes place in the moment of dis- 
charge, in order to shoot the fajcal mass out of the case, for it 
is then projected from above the rim. The fa'ces are slightly 
coherent and jelly-like, not at all like the case-pellets. The 
ventral region is, as usual, occupied by the ovary, sometimes 
granular and clear, at others filled with a dark maturing ovum. 
The head-mass, when retracted as in fig. 12, appeared separate 
and removed from the outer integument, and to be drawn 
together in a puckered manner. It descends into a small 
conical tubercle behind the gizzard, and between this and the 
base of the stomach there was one little trenmlous tag, of the 
same structure as in Nutommata aurita. From the same spot 
also project, into a space of peculiar clearness, two trumpet- 



GOSSE ON THE MELICERTA RINGENS. 73 

shaped bodies of the greatest delicacy, and without motion 
(See fig. 1-2). 

From far up in the trunk long muscular cords descend and 
pass into the foot, which they entirely traverse. This long 
organ is coiTugated into close, irregular, transverse wrinkles; 
and there seem to be annular muscle- rings, exceedingly numer- 
ous throughout. The tip of the foot is not cleft, but it has a 
retractile disc, doubtless a sucker, if this be the principle of 
its adhesion ; but near the tip, on its ventral side, there ap- 
peared a little granular body connected with the tip by a point, 
and enlarging at the upper end, where it was connected with a 
small globular vesicle. (See fig. 22.) Can this be a secerning 
gland for the secretion of an adhesive glue, by which the foot 
adheres, as in Monocerca ? 

Opening one or two cases I freed one and another very 
curious egg-like bodies (fig. 23), not symmetrical in shape, 
being much more gibbous on one side than the opposite, and 
measuring 1-1 50th by l-260th of an inch. Each was encircled 
by five or six raised ribs, running parallel to each other longi- 
tudinally, somewhat like the varices of a VVentle-trap. Viewed 
perpendicularly to the ribs the form is symmetrical — a long, 
narrow oval. The whole surface between the ribs appeared 
punctured or granulate, and the colour was a dull brownish 
yellow. Under pressure it was ruptured, and discharged an 
infinity of atoms of an excessive minuteness, but every one of 
which, for a few seconds, displayed spontaneous motion. 
Their whole appearance, and the manner in which they pre- 
sently tuined to motionless disks, were exactly the same as of 
the Spermatozoa., which the male eggs of other Rotifera con- 
tain, except that these were so minute. 

From another I extracted an eg^ of the ordinary form and 
appearance (fig. 24). It was very long, measuring 1 -145th by 
l-390th of an inch. The contained embryo was well advanced ; 
two red eyes were plainly seen by reflected and by transmitted 
light : the gizzard was transverse, very large in proportion, 
and the jaws worked vigorously ; a little opaque body, white 
under sunlight, was in the posterior part. This embryo died 
without hatching. 

May 30. — A young one, about half adult size, was at- 
tached by the base of its tube to the side of the tube of an 
adult, near the summit of the latter, so as to project oblic^uely 
upward, Tliis specimen, which was perfectly formed, gave 
me an excellent <)})portunity for obser\ing the ventral aspect 
(see fig. 14), and the dorsal (fig. 15). It had two red eyes, one 
placed near the base of each larger petal. I could not discern 
eyes in adults. It was very energetic, diligently engaged in 



74 GOSSE ON THE MELICERTA RINGENS. 

manufacturing the pellets and laying them on. It seems that 
the action of the pellet-cup is voluntary, and not always co- 
existent with the passing of the ciliary current over the chin. 
The animal frequently makes abortive efforts to deposit a 
pellet, and sometimes bends forcibly forward to the edge of 
the case before the pellet is half formed. The chin forms a 
projecting lobe, apparently concave at the tip, spoon-shaped 
or tubular (see fig. 13), well covered with cilia, which carry on 
the current from the great sinus. The petals are evidently 
thick in the middle, and I think are very abruptly attenuated 
from the ring of nervous (?) matter that runs round them, to 
the margin. The wheel-cilia have their bases on this ring, 
and not on tlie margin (see fig. 15) ; a very delicate granular 
mass runs out in a point from the base to the centre of each 
petal ; this may be cerebral, and the rings muscular. The 
edges of the petals are contracted, corrugated, incurved, and 
folded together at the will of the animal. Between the two 
larger petals is the mouth, for in the lateral view (fig. 13) 
a rather wide pharynx was distinctly seen extending from 
that point to the summit of the gizzard, and minute particles 
were traceable through it, which were rapidly poured be- 
tween the jaws. The lower portion of this duct is seen also 
in fig. 14. The breast, between the diverging antennae, forms 
several irregular rounded lobes, and below the gizzard it is 
constricted laterally. 

There is a very close affinity between Melicerta and the 
Philodinadce, say, for example. Rotifer citrinus. The wheels 
are sinuous instead of round, but the great sinus and pro- 
jecting spoon-shaped chin are in both ; the antenna, single 
and medial in Rotifer, is repeated and thrown apart in 
Melicerta, but the structure is identical. The gizzard is 
essentially the same — a pair of muscular hemispheres with 
hard transverse teeth : the stomach and intestine are the 
same ; and the upward direction and production of the rec- 
tum are but trivial modifications dependent on a tubicolous 
habit. The structure of the foot is, however, nearer to that 
of Brackionus, or perhaps Pterodina, being corrugated, not 
telescopic-jointed, and terminating in a sucker, not in toes ; 
but this again is a tubicolous modification. 

May 31. — On looking into the live-box, in which were 
several tubes, T found a young one swimming rapidly out in a 
giddy, headlong manner. I believe it was just hatched. Its 
form was somewhat trumpet-shaped, or like that of a Stcntor, 
with a wreatli of cilia around the head, interrupted at two 
opposite points. The central portion of the head rose into a 
low cone. After whirling about for a few minutes, its motion 



GOSSE ON THE MELICERTA RINGENS. 75 

became retarded, and it began to adhere momentarily, and to 
move forward by successive jerks, not more than its own 
length at once. The periods of its remaining stationary in- 
creased, so that I several times supposed it had taken up its 
permanent position, when some shock or alarm would send it 
off for a little distance again. At length, about an hour after I 
first saw it, it finally settled, adhering by the foot to the lower 
glass of the box. Fig. 25 represents the ventral, fig. 26 the 
dorsal outline of this young one, but more I could not sketch, 
for after a few rapid gyrations upon the foot as a pivot, it 
became vertical, and appeared to the eye looking down on it, 
as at fig. 27. The form of the adult was now distinctly 
assumed, the four petals of the disk were well made out, 
though the sinuosities were yet shallow : the antennae at first 
were only small square nipples (fig. 27, a a), but soon shot 
out into the usual form ; the ciliated chin was distinct, as was 
also the whirling of the pellet-cup immediately beneath it. 
A pellet was quickly formed, and instantly deposited at the 
foot ; the same operation was repeated with energy and in- 
dustry, so that in a few minutes a row of pellets wgre seen, 
forming a portion of a circle around its foot-base, as shown 
at fig. 27, b. When two or three rows were formed, I took 
occasion to measure the time of their construction ; one pellet 
was deposited every minute with great regularity. I mixed a 
little carmine with the water : the result was beautiful ; for 
the dark torrent that poured off in front, and the appearance 
of a rich crimson pellet in the cup (fig. 27, c), were instanta- 
neous. Yet the imbibition seemed deleterious ; for the 
animal would withdraw itself suddenly, after a revolution or 
two, and presently retired sullenly, having laid five or six 
carmine pellets, whose deep tints made them conspicuous on 
the pellucid yellowish ones. Some three hours after, I saw 
that no more were laid. But in the course of the night the 
case was considerably increased with carmine ; the part so 
made was much less regularly formed of pellets than that 
composed of the natural material, for the red portion was all 
confused and blended as it were into a mass, without distinc- 
tion of pellets, though retaining the tubular form. 

A large one, whose case had become accidentally injured 
near the base, so as to be slit for some distance up, protruded 
itself through the opening, remaining still attached by the 
foot. It did not again enter, but continued for several days, 
carrying on all its functions in the healthiest manner, exposed. 
It frequently made pellets, but these were never deposited, 
but allowed to wash off into the water, nor was any attempt 
made to construct a new case. A half-grown one, very active. 



76 ON THE CORNEA OF THE EYE IN INSECTS. 

that was near, deposited pellets only rarely, ei^lit or ten in 
several days ; whence it appears that this process is quite 
voluntary : indeed, if it were not so, so rapid is the formation, 
that the tube would be increased beyond all bounds in a very 
brief period of the animal's life. 

The process of swallowing carmine enabled me to see very 
distinctly that (as shown at fig. 14) the oesophagus enters the 
gizzard between the larger ends of the jaw-mullers, and that 
the stomach-duct leads off from their smaller ends, through 
the semi-globular lobe beneath. This duct, though short and 
wide, is distinct, 

June 12. — The yomig one obtained May 30 was active 
till this morning, when it suddenly died, having lived iir 
confinement fourteen days. During the whole time it has 
scarcely increased in size, nor has it added any pellets to its 
case, except a few the first day or two. The eyes were dis- 
tinctly visible to the last. 



Remarks on the Cornea of the Eye in Insects^ with reference to 
certain sources of fallacy in the ordinary mode of computing 
the Microscopic hexagonal Facets of this mend>rane : tvith an 
Appendix, containing a brief notice of a new method of taking 
transparent Casts of the above, and other objects for the 
Microscope, in Collodion. By John Gorham, M.R.C.S.L., 
Fellow of the Physical Society of Guy's Hospital ; Honorary 
Fellow of the Royal Botanic Society of London, &c. 

The eye of the Insect tribe has been chosen for the present 
communication, nut only from its great beauty and wonderlul 
organization, but on account of its transparent portion (cornea) 
presenting a multitude of well-defined planes, forming a reti- 
culation which is especially calculated to excite our admira- 
tion. It is to this, therefore, and not to the interior, that our 
attention will be chiefly directed. 

On examining the head of an insect we shall find a couple 
of protuberances more or less prominent, and situated symme- 
trically, one on each side. Their outline at the base is for 
the most part circular, elliptical, oval, or tnincated ; while 
their curved surfaces are spherical, spheroidal, pyriform, &c. 

These horny, rounded, naked parts seem externally to repre- 
sent the cornea^ oi the eyes of Insects ; at least they are ap- 
propriatelv so called from the analogy they bear to those trans- 
parent tunics in the higher classes of animals. They differ 
from these latter, however, in this respect, that, when viewed 
l)V tlie microscope, they display a number of hexagonal facets 



ON THE CORNEA OF THE EYE IN INSECTS. 77 

which constitute the media for the ingress of light to as many 
simple eyes. Under an ordinary lens, and by reflected light, 
the entire surface of one of these cornea* presents a beautiful 
reticulation, like very fine wire gauze, with a minute papilla, or, 
at least, slight elevation in the centre of each mesh. These 
are resolved, however, by the aid of a compound microscope, 
and with a power of fiom 80 to 100 diameters, into an almost 
incredible number, when compared with the space they 
occupy, of minute, regular geometrical hexagons, well- 
defined and capable of being computed with comparative 
ease, their exceeding minuteness being taken intcj considera- 
tion. When viewed in this way the entire surface bears a 
resemblance to that which might easily and artificially be 
produced by straining a portion of Brussels lace with hexa- 
gonal meshes over a small hemisphere of ground glass. That 
this gives a toleraljly fair idea of the intricate carving on the 
exterior may be further shown from the fact that delicate and 
beautiful casts in collodion* may be procured from the sur- 
face by giving this three or four coats with a camel's-hair 
pencil. When dry it is peeled off in thin fla'.es, upon which 
the impressions are left so distinct, that their hexagonal form 
can be discovered with a Coddington lens. This experiment 
will be found useful in examining the configuration of the 
facets of the hard and unyielding eyes of many of the Coleo- 
ptera, in which the reticulations become either distorted by 
corrugation or broken from the pressure required to flatten 
them. It will be observed, also, that by this method perfect 
casts of portions of the cornea can be obtained without any 
dissection whatever, and that these artificial exuvice, for such 
they really are, become available for microscopic investi- 
gations ; obviating the necessity for a more lengthened or labo- 
rious preparation. 

But to return. The dissection of the cornea of an insect's 
eye is by no means easy. I have generally used a small pair 
of scissors, with well-adjusted and pointed extremities, and a 
camel's-hair pencil, having a portion of the hairs cut off at 
the end, which is thereby flattened. The extremity of the 
cedar handle, on the other hand, is shaved to a fine point, so 
that the brush may be the more easily revolved between the 
finger and thumb, and the coloured pigment on the inte- 
rior may thus be scrubbed off by this simple process. A brush 
thus prepared and slightly moistened forms, as far as my ex- 
perience goes, by far the best forceps for manipulating these 
objects preparatory to mounting ; as, if only touched with any 

* A solution of gmi-cottou in cliloroform. It cau be ])rocure(l of any 
chemist. 



78 ON THE CORNEA OF THE EYE IN INSECTS. 

hard-pointed substance, they will often spring from the table 
from mere elasticity, and thus the labour of hours may be lost 
in one single moment. It does not appear to me desirable to 
attempt to flatten an entire cornea by pressure and maceration, 
although I am aware this is generally recommended, but no 
useful purpose is really served either in developing the 
beauty or counting the number of its lenses. The rounded 
membrane, on the other hand, becomes, as might be antici- 
pated if the margin remains intact, corrugated, and so one 
hexagon overlaps the other. It will be useful, therefore, to 
make two preparations of the eyes of one insect, the one 
entire, retaining its naturally curved form, not having been 
subjected to any pressure — the other nicked at its margin, or 
cut into small fragments and pressed flat between two slides. 

Each of the hexagons above-mentioned is itself the slightly 
" convex horny case of an eye. Their margins of separation 
are often thickly set with hair, as in the Bee ; in other in- 
stances they are naked, as in the Dragon-fly, House-fly, «Scc. 
The number of these lenses has been calculated by various 
authors, and their almost incredible multitude has very justly 
excited astonishment. Hooke counted 7000 in the eye of a 
House-fly; Leeuwenhoek more than 12,000 in the eye of a 
Dragon-fly, and 40C0 in the eye of a domestic fly ; and 
Geoffroy cites a calculation, according to which there are 
34,650 of such facets in the eye of a Butterfl}." 

Having carefully examined with the microscope a small 
flattened portion of the eye of a Dragon-fly and a few analo- 
gous specimens, we are, I think, in a position to assume two 
things which will serve to form the basis in our calcula- 
tions: — 

1st. That the reticulations referred to are composed of per- 
fect, regular, geometric hexagons ; and 

2ndly. That the hexagons are all of equal size. 

Their number, in any individual specimen under investiga- 
tion, might, of course, be ascertained by actual enumeration ; 
the process however would be a very laborious one, and in- 
jurious to the sight. Leeuwenhoek computed them by assum- 
ing the prominent part of the eye to be hemispherical.* He 
then counted a single row of hexagons from the summit to 
the base, and this multiplied by four gave the great circle 
of a sphere, the area of which was then discovered by a 
simple arithmetical process. It will be observed, however, 
that those eyes only, the surface of whose common cornea is 
hemispherical (and there is a large number in which it is 
not), can be treated in this way ; and, if the facets could be 
* The eve under examination was tbat of the Moth of the Silk-worm. 



ON THE CORNEA OF THE EYE IN INSECTS. 



7i) 



tlius computed, the results would be incorrect according to the 
method ol Leeuwenhoek : inasmuch as in all his calculations 




the hexagons were reckoned as squares : thus many hundred 
were lost even in one single eye. Having pointed out this 
source of fallacy, we proceed to endeavour to correct it. 

A mere inspection of the above square area of hexagons 
will show that such an outline, enclosing as many regular 
hexagons of a given size as it will contain, has a less number 
on the one side, A B, than on its adjacent side, AC. A 
closer examination will discover that these numbers bear a 
ratio of 8 : 9. '25, or of 1 : 1.156 ; while, if the entire area 
is counted, not omitting the portions which are truncated by 
the sides of the square, it will be found about 74 (or 8 X 
9.25). Those numbers are not, indeed, mathematically cor- 
rect, but sufficiently so for our present purpose ; for, doubt- 
less, we have not failed to notice that if the side, A B, had 
been squared in the ordinary way (8 X 8), and not treated as 
if it were composed of hexagons (8 X 9.25), we should have 
lost as many as ten planes even in a space containing so few 
hexagons ; and these will vanish by hundreds instead of tens, 
as the area increases. 

And, if we take a circle with a row of hexagons passing 
through its great diameter, A B, and calculate from this the 
entire number spread over its whole superficies, we shall soon 
discover how very far wide of the truth our results would be, 
supposing the hexagons were treated as squares. For, first, 
let it be required to find the area of a circle in squares with 
any number, say twenty, composing its diameter. Now, the 



80 ON THE CORNEA OF THE EYE IN INSECTS. 

A 




square of the diameter X .7854 = the area : hence 20'^ X .7854 
= 314.160 the area in squares. 

Again, given a circle whose diameter = 20 regular hexa- 
gons, ananged with their sides in apposition (fig. 1), to find 
the area in hexagons. Now, as circles are to one another as 
the squares of their diameters, and as we have already seen 
that a square of hexagons = the product of 8 : 9.25, or 
numbers in that ratio, we have : — 8 : 9.25 : : 20 : 23.125. 
Hence 20 X 23.125 = 462.5, the diameter squared, and 462.5 
X 7854 = 363.247 the area in hexagons. 

Or a circular area of hexagons may be thus found : — 




Given : a circle with twenty small hexagons (arranged side 
by side, fig. 1) passing through its great diameter, to find the 



area. 



The circle of the circumscribing circle will pass so close to 
the side C I) (fig. 2) of the hexagon, that we may safely call 



EB = 



ON THE CORNEA OF THE EYE IN INSECTS. 8 I 

1 . . -. _- ... area of circle 



;rT: of the diameter. Now evidently —- 

•^O area ol hexagon 

number of hexagons ; we have therefore to find area of hex 
agon. 

BC2 = AC2-AB=4BC2-AB2 

3BO = A B^ 

area of triangle ABC 



BC X AB = 



AB^ 



A B^ /I 

area of hexagon =6— ^ =2ABV3 = 2. ( t^D 

g^ DV3 = .00125. D? 1.73025 

area of circle = .7854 D^ = .0021650625 D^ 



^/S = 



area of circle 
area of hexagon 



= no. of hexaffons = 



.7854 
,002165 



= 363 nearly. 



From these and analogous calculations, tables might be 
constructed for all possible dimensions of the square and the 
circle, the side being given in the former case, and the 
diameter in the latter : — 

Square. 



Side. 



10 

20 
30 
40 
50 
100, &c. 



Area 
in Squares. 



100 

400 

900 

1,600 

2,500 

10,000 



Area 
in Hexagons. 



115.625 

462.500 

1040.625 

1850.000 

2890.630 

11562.500 



Difference. 



15.625 

62.500 

140.625 

250.000 

390.630 

1562.500 



Circle. 



Diameter. 



10 
20 
30 
40 
50 
100 



Area 
in Squares. 



78.540 

314.160 

706.860 

1256.640 

1963.500 

7854.000 



Area 
in Hexagons. 



90.811 

363.247 

817.306 

1452.990 

2270.300 

9081.875 



Difference. 



12.271 

49.087 

110.446 

196.360 

306.800 

1227.875 



VOL. I. 



G 



82 ON THE CORNEA OF THE EYE IN INSECTS. 

A few only are necessary in this place ; but even in these 
the columns of dijfcreirce sufficiently indicate the loss likely 
to follow from miscalculation. I pass on to notice, however, that 
the only quadrilateral figure which will so contain a number of 
hexagons that its area may be discovered by squaring a side, 
is a rlwmh of 60° and 120°; that is to say, two equilateral 




triangles placed base to base. When such a plane is occu- 
pied by regular hexagons, any side, A B, may be supposed to 
consist of small rhombs ranged side by side, each being 
exactly one-third (G) of one of the enclosed hexagons. All 
the sides are alike ; hence it follows that, if one of them be 
multiplied into itself, and the product divided by three, the 
area of the rhomb, A B C D, in hexagons, is determined. 

(5-2 

Let A B = 6 rhombs, then x = 1 2 the number of hexagons 

o 

in ABC D. But the sides themselves are deduced from a 
single row of hexagons E F extending across the rhomb per- 
pendicularly with respect to A D and B C ; and it is to be 
remarked that the number of rhombs in a side is always 
double of that of the hexagons composing this perpendicular 
series. In the figure there are three such hexagons E F, 
and consequently six rhombs in a side. The hexagons can 
always be calculated therefore by the formula 

{a X 2f 

3 

where a represents the number of hexagons in tlie perpendi- 

cular series. Let a = 3 then ^ — I = 12 the area of 

3 

ABCD. 

Allusion has been made to Leeuwenhoek's calculations of 
the lenses of the silkworm's eye. These may now be cor- 
rected. 

The number of facets, counted from the base to the 



ON THE CORNEA OF THE EYE IN INSECTS. 83 

summit of the hemispherical cornea, in the eye of the silk- 
worm moth, is thirty-five. But a single row, extending over 
a space = one quarter of the great circle of a sphere, X 4 
= the circle itself, or 140. Now, the area of a sphere = 
four times the area of its great circle, and the area of a great 
circle = the square of the diameter X .7854. Again, the 
great diameter = the circumference -f- 3.1416. Thus, 

140 

7ri~mr = 44.563 diameter of the circle 

3.141 b 

44.563 X 51.525 (i. e., in the ratio of 8 : 9.1-25) = 2296.108 

squares of diameter in hexagons 

2296.108 X .7854 = 1803.363 area of circle 

and 1803.363 x 4 = 7213.452 - - area of sphere in hexagons 

-^ = 3606.726 hexagons in superficies of one he- 
misphere or eye. 

Spherical area according to Leeuwenhoek, with the 

hexagons counted as squares = 6236 

Spherical area computed as above, with the hexa- 
gons considered as such = 7213 

Number lost by Leeuwenhoek = Difference 977. 

We have seen how easily a surface of hexagons, whether 
it be circular or hemispherical, square or rhombic, may be 
computed from a single row ; and we have now to procure 
sections of eyes, presenting such shapes for inspection under 
the microscope. To excise small fragments from such minute 
and fragile membranes, and those of regular and determi- 
nate figures, requires nice manipulation. The quadrilateral 
figures I have been in the habit of making, by enclosing the 
membrane between two pieces of gummed white paper, upon 
one side of which the parallelograms are drawn ; they are 
then cut entirely through with a penknife, and soaked for a 
short time in cold water, which softens the gum, and thus 
separates the paper. Circular sections are made with a small 
punch, after having been enclosed between paper as above 
recommended. On the surface of a small circle of the eye 
of a Dragon-fly, excised with the smallest saddler's punch, 
marked No. 1, I have counted about 800 facets; in another, 
a size or two larger, about 5000, and so on. I have not felt 
satisfied with many of these preparations, however, although 
several have come out very well. Their edges are often 
lacerated by the punch, while the parallelograms, when 
magnified, have presented considerable deviations from the 

g2 



84 ON THE CORNE.'V OF THE EYE IN INSECTS. 

true parallel. These inconveniences are obviated by making 
small apertux'es, of the required shape and size, in black 
paper, which are placed immediately over the specimens to 
be examined. The circular openings can be punched out, 
while the others can be removed with a sharp knife. A 
simple and not inelegant mode of procuring very small rhombic 
apertures, perfectly equilateral and equiangular, consists in 
excising two small equilateral triangles from two slips of 
black paper, and sliding one over the other until the small 
rhomb in the centre, produced by their mutual intersection, 




"^ 



s 




is of the required size. The cornea is placed under this 
rhombic aperture, and the lenses are viewed and counted 
through it, by merely enumerating one row extending in a 
perpendicular dii'ection, with respect to any two opposite or 
parallel sides, and joining them as in the dotted line of the 
annexed rhomb. 



Appendix. 

This is the first time, I believe, that the collodion has been 
employed in the production of transparent membranes for 
microscopic purposes. There are reasons for supposing that 
it will enable us to construct a series of novel and highly 
interesting preparations, by its presenting the minute tracery 
observed on the surface of many opaque objects in a trans- 
parent form. In this way we can multiply impressions of 
specimens which are very beautiful or very rare. It bids 
fair, also, to put us into possession of the general configura- 
tion on the surface of certain minute fresh vegetable struc- 
tures which become shrivelled, and their beauty obliterated 
in drying. It is best applied as follows : — A few chips of 
Red Sanderswood are shaken up in a drachm or two of good 
collodion ; the surface of the object is then painted over four 
or five times, and in less than ten minutes the flake or cast 
of collodion can be peeled off, and mounted on a slide under 
a thin cover as a dry preparation. 



( 85 ) 

Remarks on the Preparation of the Polypidoms of Zoophytes 
for Microscopical Examination^ with a notice of the phe- 
nomena tJtey exhibit ivith polarized light. By Goldixg 
Bird, A.M., M.D., F.R.S., Fellow of the Royal College of 
Physicians. 

Almost every miscroscopic observer is familiar witli the 
extreme beauty of the horny polypidoms of the Anthozoa, 
and the calcareous structure of the Polyzoa, when examined 
as transparent objects in their recent state. There are few 
persons who have not regretted the extent to which these 
become disfigured by drying, so as to afford hardly an idea of 
the elegance which had previously rendered them so attractive. 
The failure of all attempts to preserve them in balsam and 
restore them to their original transparency and sharpness of 
outline in4uced me, during a recent visit to the coast of Pem- 
brokeshire, to try some experiments in the hope of over- 
coming this difficult}', whicli have yielded some interesting 
results. 

The great obstacle to preserving these structures in balsam 
arises from their retaining, when dried, air in their tubes and 
cells so obstinately that it is hardly practicable to get rid of 
it, as well as from their shrivelling up in the process of dry- 
ing. By the following plan I find the polypidoms may be 
preserved as permanent preparations, retaining the appear- 
ance of the most beautiful recent specimens, wanting only the 
expanded tentacula of the former inhabitants of their cells to 
complete the appearance they present when living in their 
native seas. 

The specimens should, if possible, be preserved in weak 
spirit until leisure is afforded for their preparation : if, how- 
ever, they have been dried, they should be soaked in cold 
water for a day or two before being submitted to the following 
processes. 

1. Select perfect specimens of the proper size for the 
microscope, which in the larger zoophytes should not exceed 
two inches in length. Immerse them in water, heated to 
120°, in a glass cylinder, and place them under an air-pumj) 
receiver. Slowly exhaust the air ; torrents of bubbles are 
given off from the surface of the tubes and cells, and very 
soon the water will appear to be in a state of active ebullition. 
In a few minutes re-admit air into the receiver, and after a 
short time again exhaust ; repeat this three or four times. 
By this process the air is removed from the cells and tubes, 
watery vapour taking its place ; at the same time, by the re- 
peated admission of water into them, and its removal during 
the process of exhaustion, the internal structure ol the poly- 



8G Du. GOLDING BIRD ON THE POLYPIDOMS OF ZOOPHYTES. 

pidoms becomes freed from the dead polypes and other 
animal matter. With the exception of a few of the cellular 
Polyzoa, especially Flustra foliacea and Gemellaria loricnta, I 
have never found any difficulty in thus removing every air- 
bubble. 

2. The polypidoms should now be removed and allowed to 
drain for a few seconds on a piece of bibulous paper, and then 
placed in an earthen vessel fitted with a cover and previously 
heated to about 200^ The best thing for this purpose is 
one of the common, thick, white pots, with its cover, used 
used by druggists to hold ointment. These are so thick 
that they retain their temperature sufficiently long for the 
purpose required. They are most conveniently heated by 
boiling them for a few minutes in water, lifting them out with 
a pair of forceps, and hastily wiping them with a thick cloth. 
The specimens, being dropped into one of these vessels, 
and covered with the loosely-fitting lid, are then to be placed 
under the receiver of an air-pump, and the air rapidly ex- 
hausted. By this process the specimens are very quickly and 
completely dried, the water being evaporated from the cells 
and tubes so rapidly that they hardly collapse or wrinkle. 

3. The specimens are to be removed in an hour or two from 
the air-pump, and dropped into a glass cylinder containing 
perfectly transparent camphine. This may iDe quite cold when 
the horny, tubular polypidoms, as those of the Sertulariae, are 
used, but should be previously heated to 100°, when the cal- 
careous, cellular Polyzoa are the objects to be preserved. The 
vessel, being covered with a large watch-glass, must be placed 
on the air-pump, and the air exhausted and re-admitted two 
or three times. After this the vessel may be set aside until it 
is convenient to place the specimens in balsam in the following 
manner : — 

4. One of the slips of glass intended for each specimen 
should have a narrow piece of card-board fastened by a little 
glue to each end so as to prevent the subsequent injury of the 
structure from pressure. The slip thus prepared should then 
be carefully cleaned from any dust, and be held over a spirit- 
lamp to warm it sufficiently to allow the balsam to flow freely 
over it. This should be applied by means of a thick glass 
rod, so as to cover the glass with a large body of balsam. All 
air-bubbles must be carefully removed by a needle point in 
the usual way. Whilst still warm, the polypidoms (previously 
removed from the camphine and drained for a minute in a 
watch-glass) should be grasped by a pair of forceps and care- 
fully immersed in the balsam. A second plate of glass, 
without the pieces of card, should be quickly warmed on the 
spirit-lamp, and a tiiin layer of balsam sj)read over its surface. 



Db. GOLDING BIRD ON THE POLYPIDOMS OF ZOOPHYTES. 87 

It must then be carefully placed ovei* the specimen, by allowing 
one end to rest on one piece of card-board fixed to the slip of 
glass, and then gradually lowered. If this be adroitly done, 
not a bubble of air will be entangled in the preparation. The 
plates should then be gently grasped in the middle by the 
wooden forceps or fingers, and fastened together by means of 
the smallest quantity of sealing wax at each end. Slips of 
paper are to be carefully pasted round the sides and ends, and 
the preparation may then be preserved without injury. 

Thus prepared, such specimens become the most beautiful 
of transparent objects for the miscroscope. Their translucency 
is as complete as in the fresh zoophyte. The structure of the 
cells and vesicles is most beautifully exhibited. Scarcely any 
more beautiful objects for the microscope can be thus obtained 
than those of the common Sertularia ahietina and 0])ercuIata. 
The vesicles in each are most interesting. The curious mouths 
of the former, and the opercular lids of the latter, are sure to 
arrest the attention. These objects are finely shown by a two- 
inch object-glass ; the bird's-head processes of Cellularia 
avicularia require, however, an inch-glass ; a deeper objective 
being veiy seldom required, except for making out very mi- 
nute structures. 

But it is when these objects are examined by polarized 
light that the most interesting results are obtained. For this 
purpose, let a piece of selenite be placed on the stage of the 
microscope, and the polarizing prisms arranged so that the 
ray transmitted is absorbed by the analyzer. Of course in 
the absence of the selenite, all light would disappear from the 
instrument, and none would reach the eye. On placing the 
selenite on the stage it will, if of proper thickness, allow an 
abundance of green light to be transmitted, Selenite which 
presents a bluish or violet tint when thus examined, is not so 
fitted for these observations. 

If, then, a specimen of Sertularia operculata be placed on the 
selenite stage and examined with a two-inch object-glass, a most 
beautiful spectacle presents itself. The central stem is shown 
to be a continuous tube, assuming a more or less pink tint 
throughout its whole extent. The cells assume a bluish or 
sometimes violet tint, their pointed orifices, and, indeed, their 
whole structure becoming much more distinct than when exa- 
mined by common light. The vesicles appear paler than the 
rest of the object, and their lids, which so remarkably resemble 
the operculum of the theca of a moss, being composed of a some- 
what denser structure, generally assume a yellowish or orange 
tint, so that they become beautifully distinct. This zoophyte 
is often covered with very minute Ijivalve shells, distinguished 
by the naked eye from tl-e vesicles only by their circular form, 



88 Dk. golding bird on the polypidoms of zoophytes. 

and these when present add much to the beauty of the speci- 
men, presenting a striated structure, and becoming illuminated 
with the most brilliant colours. 

Thus, when submitted to polarized light, the zoophyte 
becomes not only a most beautiful, but an instructive object, 
the relation of the cells to the tube which bears them, and the 
continuity of the latter being so readily seen. Sertularia Jili- 
cula is also an interesting object, the waved stem or central 
tube becoming of a deep dusky red, whilst the cells assume 
but little colour, renders their mutual relation very obvious. 
Se)-tularia ahietina is also a fine object, especially when loaded 
with vesicles as it so often is in the autumn. Halecium 
halicimnn, perhaps the least elegant of this class of beings, 
assumes a very interesting appearance, its cells assuming a 
moderate amount of colour. The very beautiful Plumularia 
falcata acquires fresh beauty under polarized light ; for 
although its cells do not become coloured, merely assuming 
a pale green, yet the tubular stem becomes more or less of a 
crimson hue, presenting the appearance of a beautiful feather. 
It is really remarkable how much more distinct every structure 
appears, and how much greater a charm is thrown over the 
elegant structure of the polypidoms when examined in the 
green light of the selenite. They seem almost, to an imagina- 
tive eye, to be once more in their native element. 

The most splendid tints are exhibited by the calcareous 
structure of the Polyzoa, and among these the Flustra trun- 
cata is perhaps the most interesting. When a preparation of 
this zoophyte is examined by polarized light with a two-inch 
glass without the selenite, the structure of the cells, and the 
shape of their mouths, are well seen ; but in several portions 
of the specimen the walls of the cells present the appear- 
ance of a tesselated pavement, several minute, spherical, 
coloured structures being scattered over it. On replacing the 
object-glass by one of one-half inch focus, these spherical 
bodies present the dark cross with beautiful tints in each 
quadrant, at first sight resembling the carbonate of lime I 
discovered some years ago in the urine of the horse. On 
examining them carefully, however, the polarizing structure 
will, in many of them, be found to be identical with that seen in 
the crystalline lens of the cod, or in a spheroid of unannealed 
glass when immersed in oil, and different from that of a slice of 
calc-spa or circular plate of unannealed glass. The centre of 
each spherule being occupied by a Ijlack cross with the tinted 
quadrants, the whole being circumscribed by a black circle. 
Beyond this extends a second set of black arms with more 
varied tints between them. A more interesting structure 
I have never had occasion to examine than that presented by 



Dr. GOLDING BIRD ON THE POLYPIDOMS OF ZOOPHYTES. 89 

these spherules of carbonate of lime. On placing the selenite 
plate under the specimens, the black cross and circle became 
green ; and a very beautiful result occurs from some tints 
being raised, and others depressed, in the scale of colours. 
On digesting a piece of Flustra triuicata in diluted hydro- 
chloric acid, and then putting it upon balsam, like the fresh 
specimen, this beautiful structure disappeared ; all appear- 
ances of tessellated tints and coloured spheres had vanished. 
Hence they depended upon the crystallized arrangement of 
the carbonate of lime. 

The more common Flustra foUacea is an interesting object 
on the selenite stage, but does not exhibit the peculiar polar- 
izing structure of the other species. 

Tlie Cellulai-ia avicularia is a brilliant object with the 
selenite stage, its cells being covered with plates of carbonate 
of lime ; it presents a fine display of tints, the bird's head 
appendages being exceedingly beautiful. 

The Gemellaria loricata is one of the most beautiful objects 
with the selenite, the cells assuming a pale pink, and the 
obovate orifices of each — provided apparently with a frame of 
carbonate of lime to keep them patent — assumes a fine and 
rich orange tint. 

I have alluded to some of the most beautiful of the struc- 
tures which have occurred to me ; but I feel sure, that those 
observers who have more time at their disposal, will add to 
our knowledge of the diversity existing between the polarizing 
structure of these polypidoms. I would especially draw atten- 
tion to the curious spherules of Flustra tj'ioicata ; they 
deserve a very careful examination. I was disappointed in not 
detecting a similar structure in the birds' heads of Cellularia. 

I cannot close this little communication without alluding to 
an excellent and very simple plan for preserving the zoophytes 
as wet preparations, so as to retain the polypes and their ten- 
tacular arms in situ. Ellis stated nearly a century ago, that if 
the zoophytes were plunged into brandy so as to kill them 
speedily, they might be preserved for a long time. I find, 
however, that it is better to select a very vivacious specimen 
and plunge it into cold pure water — the polypes are killed 
almost immediately, and their tentacula often do not retract : 
proper sized specimens should then be selected, and pre- 
served in weak alcohol For this purpose little phials* about 
two inches long should be made, from very thin, flat glass 
tube, so as to be half an inch wide and about a quarter of an 
inch, or even less, from back to front. The specimens being 

* Mr. I'astorelli, of Cross-street, Hatton (iankii, wlio has taken much 
[laiiis to manufacture these little flat phials, supjilies them at a very low 
price. 



90 COBBOLD ON THE ORCHIS MASCULA. 

fixed to a piece of thin platinum wire, should then be placed 
in one of these flat phials (previously filled with weak spirit), 
so as to reach about half-way down. When several of these are 
thus arranged, they should be placed in a glass cylinder and 
removed to the air-pump. On pumping out the air, a copious 
ebullition of bubbles will take place, and many of the tenta- 
cula, previously concealed, will emerge from the cells. After 
being left in vacuo for a few hours the bottles should be filled 
up, closely corked, and tied over, like common anatomical 
preparations. I find that, for all examinations with a one or 
two-inch object-glass, these bottles are most excellent, and afford 
cheap and easy substitutes for the more expensive and diffi- 
cultly managed cells. In this manner specimens of the genera 
Cycloum, Membranipora, Alcyonidium, and Crisia, exhibit their 
structure most beautifully. 

A few dozen of these little bottles hardly occupy any room, 
and would form a useful accompaniment of the microscopist 
by the sea-side. Any one who would visit the caverns in 
St. Catherine's Island, at Tenby, could reap a harvest which 
would afford instruction and amusement for weeks. In these 
caverns, so rich in zoophytes and sponges that they are really 
roofed with the Laomedece, Grantia, and their allies, whilst 
the elegant Tubularice afford a garden-like ornament to the 
shallow pools on the floor, the walls abounding with the pink, 
yellow, green, and purple Actinice, days may be spent with 
instruction and amusement of the most interesting kind. I 
have, indeed, been informed by my friend Mr. Dyster, of Tenby, 
who has devoted himself to the investigation of the inhabitants 
of these caverns with great zeal and success, that no locality 
affords, in the same space, such an abundant treat for the 
zoophytologist. I cannot too strongly recommend a visit to 
them, to all who have a few days leisure in the summer. 



On the Emhryofjeny of Orchis mascula. By T. Spencer 
CoBBOLD, M.D., formerly Senior President of the Royal 
Medical Society of Edinburgh. 

After the elaborate memoir of M. Tulasne on the vegetable 
embryo in the ' Annales des Sciences Naturelles ' for 1849, 
containing not only the results of his own extended investi- 
gations, but embodying a complete analysis of all that has 
been previously written on this subject, it is with diffidence 
that I offer the following details, which are chiefly con- 
firmatory of facts already elicited. The reviewer of Professor 
Quekett's Lectures on Histology in the first Number of this 
Journal, page 44, hints that " the question of the entrance of 



COBBOLD Ox>I THE ORCHIS MASCULA. 91 

the pollen tube into the sac of the embryo " is still one of 
interest to vegetable physiologists ; this remark has suggested 
the present communication. 

Of all the natural orders hitherto examined by the embryo- 
logist, few have been more closely studied or yielded more 
satisfactory results than the Orchidccece : the researches of 
Brown, Amici, Mohl, Muller, Hofmeister, and many others, 
are too well known to require recapitulation ; our own in- 
quiries have extended over a large number of genera, but the 
selection of a single species sufficiently demonstrates the 
question under consideration. 

Referring at once to the illnstrations, fig. 1. will be recog- 
nized as a floret of Orchis mascula, with the peduncle {ji) and 
bract {p) attached. Before fertilization is accomplished, the 
peduncle (which encloses the ovarium) begins to enlarge, con- 
sequent upon the growth of the contained ovula. Plate 11., 
figs. 2, 3, 4, and 5, indicate the successive stages of develop- 
ment of the ovula ; their first appearance is only recognised 
by a slight bulging outward of the cellular parietes (placentae) 
of the ovarian chamber, in the form of papillse, which are the 
representatives of the nucleus of the perfect ovulum (marked 
n in all the figures). The mode in which the priminc {pr.) 
and secundine {se.) are developed^ and subsequently enclose 
the nucleus, is also well shown. Some time after impregna- 
tion has been effected, the condition of the ovary assumes the 
appearance seen in fig. 6, a section of which, slightly magni- 
fied, is given in fig. 7. Bundles of pollen-tubes {pf.) run 
along the inner side of the placentae and terminate by short 
curves, entering the micropyles of the ovula {ov.) ; on the 
left side of the figure their distribution is well exhibited, the 
ovula being detached, and the pollen-tubes left pendant. 

Examining the ovules at this stage, we now perceive a cavity 
in the centre of each nucleus ; this is surrounded by a cell- 
wall, and constitutes the embryo sac (fig. 8, es.). In the 
interior of the sac granular matter exists in more or less 
abundance, being generally found thicker near the apex ; but, 
whether or not distinct cytoblasts or embryonic vesicles exist 
prior to the contact of the pollen-tube with the embryo sac 
(as is indubitably the case in numerous other phanerogamia), 
is a point not fully determined. In those instances where we 
have witnessed the union of the pollen-tube with the embryo 
sac, the granular matter has usually been found collected 
together opposite the point of application (.figs. 9 and 10), 
and, in one instance, three embryonic vesicles (<?u.) were 
visible at the apex of the sac, the pollen-tube remaining 
firmly adherent (fig. 11). This latter observation, agreeing 
as it does with what we have ourselves observed in Gestierea, 



92 BEALE ON SUBSTANCES OF 

and being; also in accordance with the views advocated by all 
later authorities, we think we cannot better close this short 
paper than by drawing the following conclusions, which may 
be regarded as embracing the leading facts and particulars 
hitherto promulgated on this interesting subject : — 

1st. That prior to impregnation the ovule contains an 
embryo sac. 2nd. That the embryo sac is commonly formed 
at the apex of tlie nucleus, ord. That in the interior of the 
embryo sac there exists a granular fluid or formative blastema. 
4th. That the sac frequently protrudes bejond the exostome 
(ovule tube; Griffith, Dickie). 5t!i. That in the interior of 
the sac, prior to impregnation, one or more cytoblasts, or 
embryonic vesicles, are formed. 6th. That their formation 
takes place by the aggregation of molecules. (Amici, Meyen, 
Hofmeister.) 7th. Tliat the cytoblasts, or embryonic vesicles, 
also contain a fluid more or less granular. {Glohulo-cellular 
cambium; Mirbel.) 8th. That the pollen is always necessary 
for fertilization (apparent exception given by Smith in Ccelo- 
hegyne ilicifolid). 9th. That the pollen, when applied to the 
stigma, sends out one or more tubes (prolongations of the 
intine), which contain granular matter (fovilla). lOth. That in 
most cases the union of the pollen tube with the apex of the 
embryo sac constitutes the very act of impregnation. 11th. 
That the result of this union is the formation of an embryo. 
12th. That this formation takes place either by the meta- 
morphosis of one of the pre-existing germinal or embryonic 
vesicles, under the dynamic influence of the fovilla (acting 
catalytically ?) ; or, as is more probable, by the union of the 
contents of the pollen-tube with that of a germinal vesicle, 
similar to what occurs in the conjugation of ConfervcB. 



On the Importance of recognising Substances of extraneous Origin 
xchen they occur in Urijie, and of distinguishing them from 
those Bodies which enter into the Composition of Urinary 
Sediments. By Lionel Beale, M.B, 

In the microscopical examination of urinary deposits, the 
observer often meets with substances whose nature and 
origin cannot readily be determined. This is due in many 
instances to the presence of bodies which have fallen in 
accidentally, or which have been placed in the urine for the 
express purpose of deceiving the practitioner. The im- 
portance of recognising matters of an extraneous origin can 
scarcely be sufficiently dwelt upon, for until the eye becomes 
familiar with the characters of tliese substances, it will be 
oh\ iously quite impossible to derive such information from a 



EXTKANEOUS ORIGIN IIN URINE. 93 

microscopical examination of the urine, as will enable the 
observer to disting-uish between those substances whose pre- 
sence denotes the existence of certain morbid conditions, from 
certain matters which have accidentally found access, and 
may therefore be entirely disregarded. Practitioners who 
use the microscope for investigating the nature of urinary 
deposits, will derive advantage from subjecting many of the 
substances referred to in the present communication to mi- 
croscopical examination, by which their general appearance 
will soon become familiar to the observer, and he will then 
be able to recognise them without difficulty should they be 
met with in the course of an examination of urine. 

As most of the undermentioned substances are readily 
obtained, a brief notice of their characters will be sufficient ; 
the chief object of this communication being to direct the 
notice of practitioners to the fact of the frequent occurrence 
of many of them in urine, and to draw attention to those 
characters in which they resemble, or are liable to be mistaken 
for, any insoluble constituent of the urine. I may remark 
that among many substances whose presence is accidental in 
urine, the following are some of the most important that have 
fallen under my own notice : — Human hair, cats^ hair, blanket 
hair, coloured worsted, fibres of cotton, flax, and silk, small 
portions of feathers, fibres of wood sivept from the floor, starch, 
globules of various kinds, fragments of potato, bread-crumbs, 
portions of tea-leaves, common house sand, oil globules Once, 
a specimen of urine, which had been sent to Dr. Todd for 
examination, was found to contain several white bodies about 
half an inch in length, which upon microscopical examination 
I found to contain trache^p, and they ultimately proved to be 
larvoi of the blowfly, although it had been stoutly affirmed 
that these had been passed by the patient. A few days since 
Dr. Stewart informed me that a man had brought some urine 
to him for examination with a thick bright red deposit, which 
was analyzed by Mr. Taylor, and proved to consist of sesqui- 
oxide of iron. The urine containing this deposit was of spe- 
cific gravity 1011, and, upon the addition of ammonia, a brown 
flocculent precipitate (hydrated sosquioxide of iron) was thrown 
down. Dr. Stewart tells me that a considerable quantity of 
the powder remained suspended in the urine after it had stood 
for many hours, and that the fluid was still turbid after having- 
been passed through a double filter. The man who brought 
this urine has also been endeavouring to impose upon my 
friend Dr. Weber, of tlie German Hospital. 

Hair of various kinds is very frequently found amongst 
urinary deposits, but, as its microscopical appearance is so 
well known, it is not necessary to enter into a description 



9-4 BEALE ON SUBSTANCES OF 

of the characters by which it may be distinguished. The 
varieties of hair most commonly met with are human hair, 
blanket hair, and cats' hair ; not unfrequently portions of 
coloured worsted will be found, but the colour alone will 
often remove any doubts with reference to the nature of 
the substance. Portions of human hair are sometimes liable 
to be mistaken for naiTow casts of the uriniferous tubes 
— such as are quite free from epithelium or granular mat- 
ter, and which present throughout a homogeneous appear- 
ance. The central canal in many cases will be sufficient 
to distinguish the hair from every other substance likely 
to be mistaken for it, but sometimes this cannot be clearly 
made out, and the marks on the surface may be indistinct, 
when attention must be directed to its refracting power, 
well-defined, smooth outline, and also to the sharply trun- 
cated ends, or to its dilated club-shaped extremity in the 
case of the hair bulb. In these points small portions of hair 
will be found to differ from the cast, for this latter does not 
refract so strongly, the lines on each side are delicate but 
well defined, and the ends are seldom broken so abruptly- as in 
the case of the hair. Cats' hair can scarcely be mistaken for any 
urinary deposit with which I am acquainted, and its transverse 
markings will serve at once to distinguish it with certainty. 

Cotton and flax fibres are very often found in urine. When 
broken off in very short pieces they may be mistaken for 
casts, but the flattened bands of the former, and the some- 
what striated fibres of the latter, will generally be found suf- 
ficiently characteristic. 

Portions of feathers are often detected in urinary deposits 
upon microscopical examination, and are derived, no doubt, 
from the bed or pillow. Their branched character will 
always enable the observer to recognise them with certainty. 

Pieces of sill£ are not unfrequently present, but these can 
scarcely be mistaken for any substances derived from the 
kidney. Their smooth, glistening appearance and small 
diameter at once distinguish them from small portions of 
urinary casts, and their clear outline and regular size from 
shreds of mucus, &c. 

Fibres of deal from the floor. Of all the extraneous mat- 
ters likely to be met with in urine, and calculated to deceive 
the eye of the observer, none, perhaps, is more liable to be 
mistaken for a portion of a transparent cast, than a short piece 
of a single fibre of deal. In hospitals, where the floor is un- 
covered and frequently swept, portions of the fibres of the 
wood are detached, and, being light, may be very readily 
bhjwn into any vessel which may be near. In fact, these fibres 
enter largely into the composition of the dust which is swept 



EXTRANEOUS ORIGIN IN URINE. 95 

up. I became familiar with the appearance of these bodies 
for a long' time before I ascertained their nature, for, although 
the peculiar character of coniferous wood is sufficiently well 
marked, when only very small portions are present, and in a 
situation in which they would scarcely be expected to be 
met with, their nature may not be so easily made out. Often 
only two or three pores may be seen, and not unfrequently 
these are less regular than usual, in which case they may 
be easily mistaken for a small portion of a cast with two or 
three cells of epithelium contained within it. I have very 
frequently met with these fibres amongst the deposit of 
various specimens of urine which have been obtained from 
patients in King's College hospital. 

Starch g^raiiules are very commonly found in urinary de- 
posits ; usually their presence is accidental, but large quanti- 
ties of starch have often been added for purposes of deception, 
in which case their true nature may be discovered, either 
by their becoming^ converted into a jelly-like mass on being 
boiled with a little water in a test tube, by their behaviour 
upon the addition of free iodine, or by their well defined 
microscopical characters. The three kinds of starch most 
likely to be met with in urine, are potato starch, wheat 
starch, or rice starch. They are readily distinguished by 
microscopical examination. Small portions of potato, or pieces 
of the cellular network, in which the starch globules are con- 
tained have been occasionally met with. Under the head of 
starch, may also be included bread-crumbs, which are very 
commonly present in urine, and have a very peculiar appear- 
ance, which may be so easily observed, that a description 
would appear superfluous. Many of the starch globules will 
be found cracked in places, but their general characters are 
not otherwise much altered. 

Portions of tea-leaves are occasionally found in urine. The 
beautiful structure of the cellular portions, and the presence 
of minute spiral vessels, distinguish this from every other 
deposit of extraneous origin. A small piece of a macerated tea- 
leaf will be found to form a most beautiful microscopic object. 

Milk is sometimes purposely added to urine, in which case 
there is danger of mistaking the specimen for one of the so- 
called chylous urine, from which, however, it may be easily 
distinguished by the presence of small oil-globules, with a 
well defined dark outline, while the fatty matter in chylous 
urine is in such a minute state of sub-division, that it only 
presents a granular appearance under the microscope. 

Fatty Matter. The existence of fatty matter in urine is a 
subject of so much importance to the practitioner, and its 
accidental presence so frequent, that it may be well to consider 



96 BEALE ON SUBSTANCES OF 

the different forms in whicli it occurs, instead of simply 
describing the manner in which fat of accidental origin may 
be distinguished from oily matter, which has been excreted 
by the kidney. Upon the presence or absence of this deposit 
often depends the prognosis of a case, and hence it is of the 
utmost importance to recognise that form which is charateristic 
of fatty degeneration of the kidney with certainty. 

Fatty matter occurs in urine in at least three distinct forms. 
The first form which I shall notice, is that in which it is 
met with in certain specimens of chylous urine, and the 
peculiar milky appearance of the secretion is entirely due to 
the existence of fatty matter in an exceedingly minute state of 
division. Upon microscopical examination of such a speci- 
men, all that can be detected is a multitude of minute granular 
particles, not unlike those of amorphous lithates, scattered all 
over the field. Upon carefully focussing, it Avill be observed 
that each particle is in constant motion, and the movements 
resemble those met with in chyle and certain other fluids. 
That these particles are really composed of fatty matter in a 
minute state of division is shown, by the addition of ether to 
the urine, which immediately becomes clear ; and by the 
evaporation of the etherial solution, the fatty matter may be 
obtained in its usual form. From a remarkable specimen of 
the so-called chylous urine, for whicli I am indebted to the 
kindness of my friend Mr. George Cubitt, I obtained as much 
as 13" 9 grains of fatty matter from 1000 of urine ; the whole 
of this large quantity having previously existed in the urine 
in the minute state of division to which I have just alluded. 
In such instances, it is clear that from microscopical examina- 
tion alone, it would be quite impossible to determine the 
nature of the substance to the presence of which the peculiar 
character of the urine was due. 

The second form in which fatty matter is found in urine is 
that of globules, each globule consisting of one portion of 
fatty matter, which either floats freely upon the surface of the 
urine, or is carried to the bottom in consequence of becoming 
entangled in some heavier deposit, as for instance mucus, or 
cells of epithelium. In this case, the oil particles will pro- 
bably not be very numerous, and they are too large to give to 
the urine the opalescent appearance, Avhich results from the 
suspension of fatty matter in a molecular state. The globules 
appear in the microscope as highly refractive particles, of a 
perfectly circular form, with a dark and well defined outline. 
The more minute of these globules present the appearance of 
a perfectly round black spot. It is in the form of distinct 
and separate globules that fatty matter is found in urine, 
when it finds access into that fluid accidentally, as, for instance, 



EXTRANEOUS ORIGIN IN URINE. 97 

if a small particle of butter or a little oil fall Into the urine ; 
or if urine drawn off by an oiled cattieter be subjected to 
examination, the oil globules will present this character, and 
usually they vary very much in size, some being often of 
considei-able diameter. 

The third form in which fatty matter is met with in urine, 
differs from the preceding in this essential particular, that 
many distinct and separate oil globules, often varying much 
in size, will be found collected together ia the interior of a 
cell ; at the same time, a certain number of free oil-particles 
may be observed. In a collection of oil particles invested 
with a cell-membrane, the term " fat cell " has been applied, 
and it is to these cells found in the deposits, and entangled 
in casts of the uriniferous tubes, that so much attention has 
been directed of late, in reference to the indications of the 
existence of fatty degeneration of the kidney afforded by the 
presence of these bodies in the urine. 

Hence by carefully observing the particular character 
which the oily matter assumes, there is little danger of being 
mistaken in reference to its origin. 

Infusoria and fun^i. — After urine has been kept for some 
time, various forms of fungi, and not unfrequently some in- 
fusorial animalcules may be present — vibriones, vorticellae, 
and monads are among those most commonly met with, but 
many other forms are frequently present. The period of time 
which elapses previous to the development of vibriones and 
fungi is found to vary very much in different cases ; these 
bodies being sometimes found in urine within an hour after it 
has been passed, while in other cases the urine may be kept 
for many days without the development of any animal or 
vegetable organisms whatever. 

Alany other matters of extraneous origin frequently form- 
ing part of an urinary sediment might be here described, but 
as most of these will doubtless occur to the mind of every 
observer, and as their nature is often easily determined, it is 
unnecessary to enter into further description, which would 
prolong this paper to too great a length. It is hoped, how- 
ever, that enough has been said to draw the attention of 
observers to the importance of the subject, and to point out 
the necessity of rendering the eye familiar with the characters 
of many other substances than those which really enter into 
the formation of urinary deposits, before the microscopical 
examination of urine can be successfully employed in clinical 
investigation. 



VOL. I. 



( 98 ) 
TRANSLATIONS. 



Description of Actinophrys Sol. By A. Kolliker. [''roui 
Siebokl and KoUiker's Zeitsch. : i., p. 198. 1849. 

(Continued from page 34.) 

General Considerations. 

To the above description of Actinophrys, it will not be out 
of place to add a few general reflections, and in the fii'st place 
to ask what systematic position it is entitled to take. 

When compared with the simplest known forms of animal 
life, it appears clear that Actinophrys is most closely allied to 
Amoeba and the Rhizopoda of Dujardin, who himself agrees in 
this view, and considers that it differs from them only in the 
uncommon slowness with which the tentacles are moved. In 
fact Actinophrys, like Amceba, Gromia, (Sec,, consists of a per- 
fectly homogeneous, everywhere contractile substance, without 
any trace of structure, and having in precisely the same way 
processes on the surface of an ephemeral nature and of various 
forins. The granules also of Actinoj)hrys and its clear spaces 
have their analogues in the granules of Amceba and Gromia and 
in the vacuoles of Amoeba, Arcella, Trinema, and Gromia. 
And just in the same way an Actinophrys artificially divided 
by Eichhorn, finds its exact counterpart in an Amoeba prin- 
ceps, the same observation being made also by Dujardin. It 
must be confessed that, notwithstanding this correspondence, 
Actinophrys exhibits a great peculiarity in its mode of taking 
nourishment. But is it ascertained, it may be asked, that the 
Amoebae and Rhizopoda take in their food in any other way ? 
By no means ; much rather does it seem, to the author at 
least, from all that is known as to the mode of feeding in those 
creatures, to be indicated, that it is precisely similar to that 
which obtains in Actinophrys. We have only to refer to 
what Dujardin remarks with respect to Amoeba (Infus., p. 
228 et seq.) to see that he was very near the discovery of the 
remarkable proceeding witnessed by the author in Actino- 
phrys. Referring to the circumstance that in the first place 
there is in Amoeba neither mouth nor intestine, and secondly, 
that, nevertheless, Naviculae, Closteria, fragments of algcp, 
and other nutritious particles occur abundantly in its interior, 
having been admitted at any part of the surface at will — it 
may be held as an establish(>d fact, that the admission, diges- 
tion, and rejection of the food is effected in Amaha precisely 



KOLLIKER ON ACTINOPHRYS SOL. 99 

in the same way as in Acfiitophi't/s. Dujardin, moreover, 
himself, althou2:h he assumes that the Amoeba? are nourished 
by means of absorption, and that the nutritious matters above 
mentioned, enter them only by accident, is not inclined to deny 
that they do derive nutriment from the articles thus in- 
cluded ; adding (p. 229) — ' Si toutefois on voulait pretendre, 
que ces corps etrangers sont entres par une bouche, et sont 
loges dans des estomacs, il faudrait admettre, que cette bouche 
s est produite surun point qtielconqu€,et a la volant^ de VAmibe^ 
pour se refermer et disparaitre ensuite, (this recalls Ehrenberg's 
expression (p. 128), that the true mouth of the Amoeba opens 
only in the act of swallowing and rejection,) tandis que les 
estomacs eux-memes, depourvus de membrane propre, se creu- 
seraient indifferemment qk et la au gre de I'animal, pour dis- 
paraitre de meme ; dans ce cas les mots seuls seraient diffe- 
rents et I'explication des phenomenes resterait encore celle, que 
j'ai donne.' The latter is by no means credible, and it is 
rather to be asserted that it is not by chance, but by will (sit 
venia verbo) that the food enters the body in the Amoeba. 
What holds good in Ama^ba may also be supposed to be 
the case in the closely-allied Rhizopoda, which, although they 
have no vestige of a mouth, nevertheless contain Infusoria and 
Bacillariae, as has been seen by Dujardin in Arcella vulgaris 
(p. 247) and Euglypha tuberculata (p. 251), and by Ehren- 
berg in Difflugia enckelys (p. 132) and Arcella vulgaris (p. 
133), where even it is remarked, that the latter takes in 
Indigo, and that in feeding, a spot in the interior of the soft 
body — from time to time opens and closes — of lohich spots also 
two are frequently present. 

Relying upon all this, the author is of opinion that Actino- 
phrys belongs to the same group with Amoeba and the 
Rhizopoda of Dujardin, and to which group the latter name 
seems most appropriate. Distinct families would be formed 
of the Amoeba^, the species of Actinophrys, to Avhich probably 
also the genus Acineta would belong ; and of those provided 
with shells, which again might be divided into those with a 
simple body {Arcella, Difflugia, Gromia, «Scc.) and those with 
a simple semi-divided body, the Polythalamia {Miliola, Vorti- 
cialis, &c.). The character of these Rhizopoda would in part 
be that already given by Dujardin : a structureless body of a 
homogeneous, contractile substance, without mouth, intestine, 
or other organs, with mobile processes. Reception of food at 
any part of the surface of the body, by a retraction of the sub- 
stance and the introduction of the morsel into the interior ; 
digestion of the aliment in spaces temporarily formed for the 
purpose, and expulsion of the remains at any spot at will. 
Propagation by fission ? by germs ? 

n 2 



100 KOLLIKER ON ACTINOPHRYS SOL. 

Havins: tlius shown the alliance of Actinopftrys with 
Amrrha, Gromia, «Scc., the position of the thus constituted 
Rhlzopotlous group with respect to the rest of the lower 
animals remains to be considered. The first question which 
here arises is, whether this group is to be placed with the 
Infusoria, or should constitute an independent class. The 
answer is difficult, since the structure of the Rhizopoda and 
Infusoria is, it must be regretted, not yet so clearly made out 
in all points as to admit of a certain comparison between 
them. The author starts with the proposition that the Infusoria 
(from whicli he excludes the Rotifera, and the Bacillaria, 
Volvocina, and Closterina belonging to the vegetable king- 
dom) all without exception consist of a single cell. He is 
of opinion that what he had shown to be the case in the 
Gregarince,'^ holds good of all the true Infusoria, as has been 
shown in the most convincing way by Siebold in his Compa- 
rative Anatomy. In this view all the Infusoria consist as it 
were of a cell, which in the one case is entirely closed (^Gre- 
garina, Opalina, Euglena,^ &c.) ; and in the other possesses a 
mouth or even two openings. No (me who examines with 
sufficient attention an Opalina, Bursaria, Nassula, &c., can 
longer entertain the smallest doubt as to this. He will find 
for the most part a contractile and structureless inembrane fur- 
nished with cilia, frecjuently partially contractile cell-contents 
with granules and vacuoles, and almost always an homogeneous, 
frequently curiously formed nucleus. 

Tliis point being once established, it may be asked, in the 
second place. Can the Rhizopoda be likened to a cell ? At 
first sight the answer would appear to be in the negative, 
seeing that they (^Amoeba, Actinojihrys, &c,) have no distinct 

* That the Gre.i^arinae are unicelhilar cannot for a moment be doubted 
by any one who has once seen these creatures ; but, on the other hand, it 
lias hitherto been a question whether they were complete animals or not. 
The author thinks that this point may now be considered as settled, since 
his more recent observations (Mittheilung, der Zuricher. naturf. Gesell- 
schaft, heft i., 1847, p. 41, and S. and K., Zeitsch., vol. i. p. 1, et seq.), 
and which have been confirmed by many excellent observations by Stein 
(Miill. Archiv., 1848, p. 182) have shown clearly that the so-called 
L'seu'lo navicdlce are the a;erms of Gregarinas. He would here, however, 
remark cursorily that the metamorphoses of the Gregarinaj into Pseudo 
navicellai, apparently from tlieir connexion in pairs, cannot be compared 
with a conjugation, as Stein is inclined to do, because in this connexion 
the contents of two Gregarina; are not mixed together as is the case in the 
conjugation of the alge, without exception, with the contents of the 
nnitcfl cells. 

t As there is scarcely any reason for doubting that Euglena properly 
belongs to the Monadina, and that it is a plant, it should be removed from 
the above category. Nor has it any distinct cell-wall, being comjjosed 
wholly of a mass of iirotoplasm. — T. 



KOLLIKER ON ACTINOPHRYS SOL. 101 

tunic equivalent to a cell-wall, and, at least many of them, no 
cell-nucleus. But it must be inquired. Is this sufficient to 
deprive them of the title of cells? With respect to the 
nucleus, it really appears to be present in some of them 
(vid. Ehrenberg's figures), and where it is wanting, as in 
Actinophrys, whose nuclear and vesicular internal substance 
above descriljed can here hardly be so regarded, a true nucleus 
may have existed at an earlier period, and be absent only in 
the full grown animal ; or again it may be entirely wanting, 
and still the animal regarded as a cell. The former supposi- 
tion is highly credible, the same thing taking place in many 
cells (human blood-corpuscle, iScc.) ; and with respect to the 
latter, it may be remarked that although in the higher animals 
the nucleus is a constant element in the cell, it is still not 
proved, that, speaking generally, there cannot be a cell without 
a nucleus, that is to say vesicles, which otherwise in all respects 
as to growth, reception and rejection of nutriment, movement, 
increase, &c., behave exactly as do cells. It may here be 
stated that certain Infusoria, which on account of their great 
resemblance to others, distinctly unicellular, must be taken to 
be altogether of a like nature, nevertheless have no nucleus. 
With respect to the membrane, it may be regarded as certain 
that there are cells with a membrane of such extreme tenuity 
as to be hardly distinguishable from the contents ; thus the 
author observed in blood corpuscles of the embryo chicken 
noticed in the act of division, that when pressure was made 
upon them, the two halves became separated, and without any 
escape of colouring matter, were again formed into perfect cells. 
Tiie blood corpuscles of the Frog under pressure behave very 
nearly like the soft substance of the filaments of Actiiioplirys, 
the processes of Aviceha, Gromia, 6cc. In the second place, 
it is to be remarked that there are cells, in which at a later 
period all difference between the membrane and the contents 
disappears — for instance, the elements of the smooth muscles 
in the higher animals — what are termed by the author fibre- 
cells. Which of these possible conditions, as concerns mem- 
brane and nucleus, obtains in the Rhizopoda, the author is 
unable to answer, not knowing with certainty whether they 
are to be regarded exactly in the light of cells or not, but he 
goes on to remark that their other relations are not opposed 
to the notion that they may be simple cells ; such as their 
structureless homogeneous contents, its contractility, and the 
\acuoles in it, resembling in all respects the contents of the 
body in the unicellular Infusoria ; then the simj)licity of their 
form and mode of taking food, so closely resembling the w.ay in 
which t!ie Infusoria introduce a morsel into their parenchyma 



102 KOLLIKER ON ACTINOPHRYS SOL. 

and there digest it. Certainly the presence of a cell-membrane 
is scarcely reconcilable with the circumstance that the body is 
capable of admitting a morsel of food at any part of the 
surface, but partly, it is not indispensably necessary to assume 
that such exists in the fully developed Actinophrys, and 
partly also it is by no means wonderful that a membrane, in 
consistence almost the same as the rest of the parenchyma, 
should be capable of being torn and of reuniting. To leave, 
however, this region of hypotheses and possibilities, it may at 
all events be stated that the notion that the Rhizopoda are 
of a nature similar to simple although modified cells, has 
especially this to recommend it, that there is little else to be 
made of them. It cannot be admitted that they consist of a 
whole aggregation of cells, and as little is it to be supposed 
that they are simply a mass of animal matter without further 
distinction, as it were, an independent living cell contents. And 
the less can this supposition be entertained, because, according 
to all recent investigations which have proved cells to be the 
elementary parts of the higher animals and plants, — as the 
initial point for further development (ova, spores, &c.), as the 
simplest form of vegetable organisms (Closterium, Navicula, 
unicellular Alga", &c.), we cannot in the animal kingdom also, 
but regard the unicellular animal as the simplest form. 
On this account it seems provisionally, best to consider the 
Rhizopoda as peculiarly modified siinple cells — which pro- 
bably may have a membrane, but in the mature condition at 
least, to all appearance have no nucleus, and to arrange 
them together with the other Infusoria in the class of Unicel- 
lular animals. 

In conclusion, the author adds a few Avords respecting the 
contractile substance of Actinophrys and the Rhizopoda in 
general. He is induced the more to do this by a very in- 
teresting Memoir by A. Ecker, ' On the Structure and Life 
of the C(mtractile Substance of the lowest Animals.' * The 
contractile substance presented in the Rhizopoda is evidently 
very nearly allied, physiologically and chemically, as well as 
in external appearance, to that which Ecker describes in 
Hydra, and has shown to exist also in other animals, and from 
the author's ol)servati()ns on those animals he cannot but 
confirm Ecker's statement. This contractile substance, termed 
by l']cker ' amorphous ' (an improved edititm of Dujardin's 
Sarcode), deserves in every case to be further investigated in 
the way pointe«l out by I'^cker, and to be compared with the 
contractile elenu-nts in the higher animals. Already, as it 

♦ !^. and K.. Z^itscb., 1'.. i. \k 2.1H. 



KOLLIKER ON ACTINOPHllYS SOL. 103 

seems to the author, is an interesting law apparent when all 
contractile parts are regarded, that only two such occur 
in the animal kingdom,— Cell-membrane and Cell-contents, 
which either by themselves alone or together constitute a con- 
tractile element. Other parts, such as the cell-nucleus and its 
derivatives — nucleated fibres, and elastic fibre — amorphous 
substance not deposited in cells — coagulated fibrine, &;c., are 
never contractile. 

1. Contractile cell-membranes occur : 

a. In unicellular animals. 1. As universally contractile 
membranes, such as are met with in Grefjarina, Leucophrys, 
Coleps, Trachelius^ Loxodes, Barsaria, Kolpoda, Urolej)tus^ 
and many other infusoria. 2. As motile processes of a con- 
tractile or motionless membrane (Opalina, Bu7'saria, «Scc.). 

b. In aggregated simple cells. 1. As in membranes con- 
tractile in toto, as in the heart-cells of the embryo in Alytes 
and Sepia, the cells of the emhxyo Plaiiaria, and those in the 
tail of the larva? in the Tunicata (Ann, d. Sc, Nat. 1846, 
p. 221), and the caudal vesicle of the Limax embryo (Ecker, 

2. As partially contractile membranes, cilia, or epithelium 
cells. 

c. In cells which are united so as to form a tube, capillary 
lymph, and blood-vessels.* 

Contractile cell-contents occur : 

a. In unicellular animals. In all infusoria in which there 
are contractile spaces, a part at least of the contents or paren- 
chyma is contractile. 

b. In non-independent cells. The spermatic filaments of 
animals which are here meant, originate as a deposit in the 
interior of cells, or, more correctly, in the nucleus of the sper- 
matic cells. 

* That the structureless walls of these canals are of the nature of 
coalescent cell membrane was shown by the author in the ' Ann. d. Sc. 
Nat., 184fi.' It is true tliat Bidder (' Verhaltniss d. Ganglien-Korper zu 
den Nervenfasern,' 1847,p. 53) has recently termed the Author's statements 
merely conjectures, although, as it would appear, simply upon the ground 
that they do not accord with his own real conjectures (1. c. p. 54). He 
adduces no facts contradictoiy to the Author's statements, and relies solely 
upon the law propounded by Rcichert, and adopted by no one but himself, 
and which is altogether incorrect — viz. that elementary fomis of ditfercnt 
histological importance never enter a continuous connexion with each other. 

This is not the jjlace to remark farther upon this question, and the 
author contents himself with observing, without meaning anything per- 
sonal, at least this much, that those who upon actual examination of the 
capillaries of the iSatrachian larva do not see that tliey are formed from 
outstarting processes and stellate cells, have not claim to the title of 
microseoiiist. 



101 KOLLIKEIi ON ACTINOPHRYS SOL. 

c. In tubes formed out of coalesced cells. Under this bead 
are to be reckoned the animal or striped muscular fasciculus, 
in which the contents are represented bj the primitive fibrillap, 
and the tubes formed out of coalescent cells bj the Sarct>- 
lemma.* 

2. Contractile membranes and contractile cell-contents, 
united into one body are seen : — 

{a). In unicellular animals ; premising that Actinophrys and 
the Rhizopoda come under this head. 

{b). In multicellular animals ; in which all the cells have 
coalesced to form a homogeneous substance. Under this head 
are to be reckoned : — 

1. The Hydrae. These, according to Ecker's investigations, 
exhibit no trace of cells — nothing, in fact, but a uniform sub- 
stance ; — they must, therefore, at least according to the author's 
view, be regarded as originally composed of a mass of cells, 
since we know that they are developed from ova, which have 
undergone the process of segmentation. 

2. The parasite of the venous appendages of the Cephalo- 

Bidder also allows no weight to the Aiitbor's observations on the deve- 
lopment of the muscular fasciculus (1. c.,p. 50), relying upon the untenable 
law of continuity sought to be established by Reicbert, and on the observa- 
tions of Hoist and Keichert (' De Structura Musculorum,' Dorpat, 1846). 
The Author, however, maintains his own opinion as the only true one, in 
opposition to the Dorpat observers. Eenewed investigations have shown 
bim that, in the chicken, in the mammalian embryo, and in the Batrachian 
larva, in all alike, the whole miiscular fasciculi originate in series of 
cells, and that each of the widely separated fibrilhT? originates in a scries 
of cells, and that they are simply moditied cell-contents. This has been 
recently confirmed also by Bendz, in the Vertebrata, and Leydig, in the 
Aimelida. With respect to the striped muscles, it is not uninteresting to 
notice the occurrence in them of anastomoses, or branchings of the entire 
fasciculus. Tbis maj- be observed in the fascicrdi of the auricle of the 
frog (fig. 6). In this case it will be found that here and there two fasciculi 
are united by a transverse fasciculus, and that there exists not merely a 
mutual application of separate fasciculi, but a continuous connexion, an 
actual coalescence. The Sarcolemma of the three fasciculi in fig. 6, for 
instance, forms three connected anastomosing tubes, and the primitive 
fibrilla3 also pass apparently without any line of demarcation from the one 
into the other, although it cannot be exactly said that they are actually 
continuous in the three fasciculi. In the same way Dr. Leydig has 
nriticed very beautifid anastomoses and branchings of the striped muscles 
in Ptscicola (S. and K., Zeitsch., B. i. p. lOS). The author has no doubt 
but that these anastomosing striped muscles, in part at least, originate 
in stellate cells ; in this case there exists a perfect analogy in the develop- 
ment of the most important higher elementary tissues, inasmuch as that 
they are all fonncd, in jiartby the coalescence of rounded or elongated, and 
in ]>art by the union, of stellate cells. Tlie latter condition lias hitherto 
been observed in the capillary blood- and lymph- vessels in the tt;rniina- 
tions of the nerves (S. and K., Zeitsch, B. i., p. 54) and in those of the 
tiacheaj in insects. 



KOLLIKER ON ACTINOPHRYS SOL. 105 

poda, which the author has named Dicyema paradoxum, in 
which exactly the same condition is found to exist as in Hjdra 
(vid. Kolliker's Bericht iib. d. Zootom. Anst. in WUrzburg, 
1849, p. 61). 

(c.) Certain cells elongated into fibres in the higher animals 
— for instance, the so termed muscular fibre-cells or the ele- 
ments of unstriped muscle ; Avhich are to be regarded as 
elongated cells, in which the membrane and contents are 
united into a soft substance. 

In this enumeration, all those parts of animals which have 
been distinctly proved to possess a contractile property are 
contained, and it is consequently apparent that all these parts, 
taken in a general point of view, fall into but few categories — • 
viz. into two, contractile cell-membranes and motile cell- 
contents. It is not thence, however, to be inferred that there 
are but two kinds of contractile elementary tissue, much rather 
must several such, more or less different, be admitted accord- 
ing as the cell-membrane and its contents assume one form or 
another. 

Such an arrangement as the following appears to be most 
suitable : — 

Contractile elementary tissues are — 

1. The amorphous contractile substance = a) a cell-con- 
tents ; h) one or several cells with membrane and contents 
united. 

2. The spermatic filaments = the formed nuclear contents 
of a cell. 

3. The cilium = an out-growth of a cell-membrane. 

4. The contractile vesicle — an entire cell-membrane. 

5. The contractile tube = a number of coalescent cell- 
membranes. 

6. The contractile fibre-cell = an elongated cell with mem- 
brane and contents united. 

7. The contractile fibril-fasciculus (animal muscular fasci- 
culus) = the contents of a series of coalescent cells, which are 
metamorphosed into a homogeneous contractile tube (vid. 
Leydig on ' Piscicola'). 

If instead of the anatomical characters, the physiological 
properties of the contractile parts are regarded, other 
groupings of them naturally arise ; thus, for instance, 1, 2, 3, 
and in which the movement is wholly independent of nerves, 
and 5, 6, 7, in which it is effected by nervous influence, would 
respectively be associated. Besides this, regard must be paid 
to the relations of the contractile element, to galvanism, cold, 
mechanical irritation, jScc This is a point, however, which 
cannot be further entered upon in this place, and the author 



106 SCHACHT ON THE MANTLE OF CERTAIN ASCIDIANS. 

concludes with the expression of a wish that his readers may 
deduce at least this, from his communication, that what is 
simple enough in nature affords a key to what is compound, 
and is therefore worthy of all consideration. 



On the Microscopical and Chemical Examination of the Mantle 
of certain Ascidians. By Dr. H. Schacht. Miiller's 
Archiv, p. 176. 184L. 

(Continued from page 29.) 

The above facts show, first of all, two things: — 1. That 
the cell-membrane in the mantle of Phallusia does not, as 
stated by Kolliker and Lowig, consist of cellulose, but rather 
that it behaves towards iodine and sulphuric acid, as well 
as towards caustic potass, exactly like an animal substance 
nitrogenous ; 2. That the homogeneous, or only in the second 
layer, slightly fibrous interstitial substance, is composed of 
tolerably pure cellulose. 

In Clavellina Kolliker and Lowig found cells in a lamina of 
the mantle, similar to those in Phallusia, also imbedded in an 
interstitial substance ; in the tunic of Salpa these cells are 
wanting, the cellulose substance contains nuclei and crystals ; 
in Pi/rosoma, they found in the structureless tunic, only isolated 
ramified cells ; the structureless membrane of Diazona is 
penetrated according to them by elongations of the fleshy tunic 
of the animal. In the tunic of Didemmim, the same observers 
again found cells, of which the membrane, though incrusted 
with carbonate of lime, was soluble in boiling potass ; in 
Aplidium they found similar cells in the interstitial substance, 
and liere also the membrane of the cells was soluble in the 
caustic potass — only the interstitial substance remaining. In 
Botryllus, according to them, the internal layer consists of 
delicate fibres, which, like the rest of the homogeneous sub- 
stance, in which nuclei and crystals occur, resist the action of 
hydrochloric acid and of potass ; the nuclei are soluble in 
potass ; the crystals insoluble in acid ; branched channels, 
dilated at the extremity, which exist in this instance, are 
regarded by Kolliker and Lowig as processes of the fleshy tunic, 

[Tlie author then details his experiments on the mantle of 
Cynthia microcosmus, and proves the existence of cellulose in 
it in a filjrous form, mixed with another substance soluble in 
caustic potass, of which the outer epidermis appears to be 
wholly composed. But whether the fil)res are composed of 
])urc cellulose, and the second nilroiienous clement is simply 



SCHACHT ON THE MANTLE OF CERTAIN ASCIDIANS. 107 

deposited between them, or whether the latter also pervades 
the substance of the fibres themselves, he is unable to deter- 
mine. The cellulose, however, in Cynthia microcosmus 
appears to differ in some respects from that in the tunic of 
Phallusia mamillaris, inasmuch as it is coloured blue by 
ioduretted chloride of zinc, wliich the latter is not. 

In this part of his paper the author describes a mode of 
procuring thin slices of very soft or yielding substances, by 
including the latter tightly between two pieces of cork and 
cutting thin slices of the whole with a razor. Tlie structure 
of the mantle in the undescribed Ascidian from Chili appears 
to be very similar to that of the Cynthia last described.] 
He then proceeds : — 

Although the methods pursued by us respectively, were 
very different, yet the results of my observations coincide in 
great measure with those of Kolliker and Lowig. In only 
one principal point do I differ from them : the membrane of 
the large cells in the mantle of Phallusia is not composed of 
cellulose. It behaves exactly like animal membrane, and is 
probably nitrogenous, and would therefore represent the pri- 
mordial sac of the vegetable cell, which exhibits precisely the 
same chemical re-actions. 

It seems to me that the observers just quoted had not seen 
the membrane of these cells, indicated by the delicate folds 
described above, as they adduce as a distinction between these 
cells and those of a plant, the coalescence of their walls, 
composed of cellulose, with the homogeneous interstitial sub- 
stance. In Didemnum candidum, it is true, they observed 
not only the membrane, but also that it was soluble in caustic 
potass ; and consequently in this case it could not be composed 
of cellulose. That I did not meet with isolated cells in the 
mantle of Cynthia as Kolliker and Lbwig did, does not surprise 
me, those observers not having found a trace of sjich cells in 
the mantle of Phallusia gelatinosa, whilst in another specimen 
they noticed nuclei and indications of these cells. It seems, 
therefore, as if the latter belonged to a definite period of the 
animal's life. 

Kolliker and Lowig at the end of their paper refer to the 
history of the development of the embryo of certain Ascidians, 
given by Milne Edwards ; from which they conclude : — 

1. Tliat the external structureless tunic of the embryo after- 
wards forms the mantle of the adult animal, consisting of 
cellulose ; 2. That this tunic, which subsequently contains 
nuclei, fibres, (Sec, is the product of the cells formed by the 
segmentation of the yelk. They believe also that the mantle of 
other Ascidians, which is perforated by vessels, as in Phallusia^ 



108 SCHACHT ON THE MANTLE OF CEKTAIN ASCIDIANS. 

is at first structureless, and in tliis condition is not composed 
of cellulose, but that cells are formed in its substance which 
multiply and secrete the cellulose ; at a latter period, however, 
themselves again disappearing. They also detected in the 
stomach and intestines of Phalhisia, Clavellina^ and Diazona, 
both the remains of Algae as well as Closteria [in salt Avater?J. 
The cellulose, therefore, would seem to be introduced from 
without ; in what way, however, it is separated from the blood, 
in order to be secreted in certain parts of the body, remains 
unexplained ; an accurate analysis, therefore, of the blood of 
the Ascidians would be of great importance. 

If, now, the occurrence of cellulose in the mantle of the 
Ascidians above described, be compared with the conditions 
under which the same element exists in the vegetable kingdom, 
the following very essential differences are apparent : — 

1. In the vegetable kingdom the cellulose constitutes the 
so-called primary cell-membrane, and the thickening layers of 
the cell deposited upon it. The vegetable cell-wall, consisting 
of cellulose, is always separated from the wall of the neigh- 
bouring cells, by an interstitial substance (intercellular sub- 
stance) which is soluble in chlorate of potass and nitric acid. 
On their being boiled, therefore, with caustic potass and by 
maceration [in chlorate of potass and nitric acid] these cells 
separate from each other ; but in the mantle of Phalhisia no 
such separation takes place, because there, the cellulose, 
although probably distinct from the nitrogenous membrane of 
the cells, itself constitutes the interstitial substance ; the in- 
tercellular substance of the plant being entirely absent. 

2. The vegetable cell is thickened by the laminated deposit 
of new cellulose in the previously existing layers of that 
substance ; such a laminated structure, which is demonstrable 
by proper treatment in all thickened vegetable cells, is alto- 
gether absent in the cellulose of the mantle of the Ascidians. 

3. In the vegetable kingdom the cellulose never occurs in 
the form of free fibres, as in the mantle of Cynthia, &c. ; the 
band in the spiral vessels of plants, apparently composed of 
a fibre, arises in the unequal development of the thickening 
layers. 

4. In the vegetable kingdom, the cellulose never appears as 
a homogeneous substance, cither between the cells or nudei of 
cells ; as is the case in the mantle of the Ascidians. 

These differences in the mode of occurrence of the cellulose 
are so essential, that it would seem to be impossible to con- 
found an animal tissue containing cellulose with any vegetable 
tissue whatever. [The appearances exhibited in a section of 
the stem of Laminaria saccharina, when treated with iodine 



SCHACHT ON THE MANTLE OF CERTAIN ASCIDIANS. 109 

and sulphuric acid, arc adduced and figured by the author, as 
a contrast to what takes place under the same re-agents in the 
mantle of Phallusia^ 

The chemical relation of the cellulose itself, however, in the 
Ascidians examined by me, is not essentially different from 
vegetable cellulose. Caustic potass has no effect upon either ; 
sulphuric acid dissolves both ; iodine and sulphuric acid 
colour both equally, blue; ioduretted chloride of zinc induces, 
it is true, in most vegetable tissues the same blue colour as 
that produced by iodine and sulphuric acid ; there are, on 
the other hand, vegetable tissues (such as, in Fucus sej-ratiis, 
Chordaria scorpioides, the wood-cells of Piniis sylvestris, &;c.) 
upon which the same re-agents produce no effect ; the iodu- 
retted chloride of zinc appears generally to be less energetic 
in its action than sulphuric acid. After they have been boiled 
with caustic potass both the cellulose-substance of the mantle 
of the Ascidians and the thickening substance of the so-termed 
plant-cell are coloured blue or violet by the ioduretted chloride 
of zinc solution, the potass probably in both cases removing 
a material which prevented the action of the re-agent. 

By maceration after Schultz's method, the last-mentioned 
material, in the Ascidians above noticed, is as little dissolved 
as the cell-membrane in Pliallusia, nor is it, in the vegetable 
kingdom, always removed by the same maceration ; the 
thickening layers of the epidermis cells of several plants are 
not coloured blue by ioduretted chloride of zinc after macera- 
tion, whilst after boiling with potass that re-agent produces 
the characteristic colour. The substance, therefore, in the 
mantle of the Ascidians, soluble in caustic potass, appears to 
be closely allied in its properties to the so-termed incrusting 
substance of the vegetable tissue. 

In the mantle of Pliallusia, we have, as I have certainly 
proved, both a homogeneous, interstitial substance composed 
of cellulose, and also indications of fibres composed of the 
same element ; besides which there are, in the interstitial sub- 
stance and between the fibres, nuclei and cells, thus the same 
elements as those which occur in Cynthia and the new species 
from Chili ; in the case of the Phallusia the cells are more 
abundant, in the latter the nuclei and fibres ; which seem 
generally to accompany each other. In the fibrous part of the 
mantle of Pliallusia we find only nuclei, and no cells ; in the 
portion, again, which consists of cells, no fibres, and but few 
nuclei. As in this case we are without any history of the 
development of the tissue, no further conclusions can be diawn 
respecting it. 

Although, in the present state of science, the occurrence of 



110 SCHACHT ON THE MANTLE OF CERTAIN ASCIDIANS. 

cellulose docs not suffice for a distinction between plants and 
animals, yet the previously established law that the animal 
cell-membrane always contains nitrogen retains its force. The 
animal cell is in all cases, as far as I know, entirely different 
from the vegetable cell. Tiie intercellular substance is always 
wanting in tissues composed of animal cells ; the animal cell 
itself coiTcsponds with the primordial sac of the plant-cell, 
which also does not consist of cellulose, but is probaljly nitro- 
genous, like the animal cell-membrane. Whilst the plant-cell 
is thickened by the secretion of cellulose around the primordial 
sac, and thus obtains the true cell-wall ; the animal cell also 
secretes a material — in the mantle of the Ascidians the same 
cellulose — but this material does not form a special envelope 
around the previously existing nitrogenous cell, the secretions 
of the individual cells, owing to the absence of any intercellular 
material, coalescing into one substance. In this way probably 
is formed the interstitial substance composed of cellulose in 
the mantle of Phallusia ; and in like manner the stroma of the 
cartilaginous tissue, which is not composed of cellulose, and 
the interstitial substance, impregnated with calcareous salts of 
the osseous tissue. The want, therefore, of an intercellular 
substance constitutes the principal distinction between the 
animal and vegetable cellular tissues. Owing to this, the 
animal cells, even in cases where cellulose occurs, never have 
a wall composed of that substance, which is characteristic of 
the vegetable cell. It is to be regretted that this diagnostic 
character is wanting in the lowest unicellular animals and plants. 

The existence of the intercellular substance has, it is true, 
been very recently disputed, with respect to the plant-cell, by 
Wigand (Intercellular Substance and Cuticula. Braunschw. 
1850). That author has termed the true intercellular sub- 
stance, which, so far as my most recent investigations extend, 
is always present, the primary cell-membrane, whilst the 
latter is not to be distinguished, either optically or chemically, 
from the thickening layers of the vegetable cells consisting of 
cellulose. 

The resume of my reseaches therefore may be thus given : — 

1. In the mantle of the Ascidians there is a substance 
insoluble in caustic potass, but soluble in sulphuric acid, 
which is turned a beautiful blue by iodine and sulphuric 
acid, and which consequently consists entirely of cellulose. 
This sul)stance constitutes the interstitial substance of the cells ; 
in the mantle of Phallusia it is homogeneous, but in CyntJda, 
«Scc., exists for the most part in a fibrous form. 

2. The mantle of the Ascidians contains, besides this cellu- 
lose, another material soluble in caustic potass, but insoluble 



SIEBOLD ON UNICELLULAR PLANTS AND ANIMALS. Ill 

in sulphuric acid, and not coloured blue by iodine and sul- 
phuric acid, and which consequently is not cellulose; in the 
mantle of Phallusia it is only sparingly present, but in Cynthia 
and the new Chilian Ascidian it is much more abundant, and 
alone constitutes the corneous epidermis of their mantle. 

3. The membrane of the cells in the mantle of Phallusia 
does not consist of cellulose ; it is coloured brown by iodine 
and sulpliuric acid ; is soluble in caustic potass, and behaves 
exactly like an animal membrane, as do the nuclei and vessels, 

4. In the mantle of Phallusia cells abound in a homogeneous, 
interstitial substance composed of cellulose ; it is only at the 
inner margin of the mantle that fibres composed of cellulose, 
with nuclei amongst them, make their appearance. In 
Cynthia, &c., there are scarcely any traces of cells, whilst the 
nuclei and cellulose fibres abound. 

5. A tesselated epithelinm, containing no cellulose, covers 
the inner surface of the mantle of the three Ascidians examined 
by me ; the outer surface of the mantle of Phallusia appears to 
possess a similar epithelium. 

6. There are two essential points of difference between the 
modes in which cellulose occurs in the Ascidians and in the 
vegetable kingdom — 1. In Phallusia the cellulose constitutes 
the intercellular substance, but does not, as in plants, form an 
integral part of the cell- wall itself; 2. In Cynthia and other 
species the cellulose forms free fibres, a form in which it is 
ncA'er observed in the vegetable kingdom. 

7. The substance of the mantle in the Ascidians is not dis- 
integrated by boiling with caustic potass or by maceration with 
chlorate of potass and nitric acid, like the vegetable cellular 
tissue into its elementary parts ; there is in it none of the 
intercellular substance universally present in vegetable tissues, 
and by which the cells are connected, but which intercellular 
material is never composed of cellulose, as it resists sul- 
phuric acid, but is soluble in caustic potass, as well as by 
maceration. 



On Unicellular Plants and Animals. By C. Tii. v. 
SiEBoLD. From Siebold and Kolliker's Zeitsch. f. w. 
Zool. Bd. 1, p. 270. 

In the first part of my work on the 'Comparative Anatomy 
of the Invertebrata,' published in 1845, I have arranged the 
Protozoa (^Infusoria and Rhizopoda) as unicellular animals ; 
thus separating them from a series of minute organisms, de- 
scribed by Khrenberg as Polygastric Infusoria, viz. the Clos- 



112 SIEBOLD ON UNICELLULAR PLANTS AND ANIMALS. 

terina, Bacillaria, and Volvocina, which I referred to the 
vegetable kingdom. The limits of that work did not allow 
me to adduce more than the most important reasons by which 
I had been induced to come to this conclusion. I could well 
foresee that in the publication of these views I should be 
placed in direct opposition to Ehrenberg's authority ; an 
authority so generally recognised. Ehrenberg had already 
reproachfully said that I should have been more careful in 
protecting science against new opinions respecting the or- 
ganization of microscopic organisms, which are easily intro- 
duced, but not so readily dissipated. I can assert, however, 
that having for years entertained doubts as to the correctness 
of Ehrenberg's views as to the organization of the lowest 
animals, I have not ventured to oppose so great an authority, 
unless prepared by the assiduous study of the lower organ- 
isms, and that the deeper did I enter into this inquiry the 
deeper did my doubts, with respect to Ehrenberg's views, 
become rooted. 

How very much disinclined I have been from the first to dis- 
seminate lightly and incautiously, eiToneous views in science, 
is shown by the way in which I acted with respect to an en'or 
I had fallen into, in the year 1836, and with which I was charged 
by Ehrenberg in 1848, meaning me, when he says, w ithout men- 
tioning my name, " the author of the new genus of an inch-long 
double animal {Syngmnus trachealis), which, after the publi- 
cation of his correct anatomy of it, it was necessary for some 
one else to remark is nothing but a pair of strongyli in the 
act of conjunction, as he himself acknowledges." — Wieg- 
mann's Archiv, 1837. This error, the moment I knew it, I 
recanted ; so that it was not quite a year before the scientific 
world. On the other hand, how obstinately does not Ehren- 
berg adhere to the chain of delusions and errors in which he 
has more and more closely involved himself from year to year. 
In vain, hitherto, have other naturalists in Germany, on the 
Seine, and on the other side of the Channel, endeavoured to 
draw either Ehrenberg or his followers from their erroneous 
ways, and to set them on the right path ; and I will therefore 
direct the attention of the latter to a voice, which, even from 
the other side of the Alps, has made itself loudly heard in 
opposition. Meneghini, of Pavia, seeking to prove the vege- 
table nature of the Closteria and Desmidiaceyp, thus expresses 
himself on the sul)ject of Ehrenberg's errors : — " Cosa se ne 
deve dedurre ? Che anche il piii accurato osservatore e 
r uomo de genio possono errare. Ne cib potra mai scemarne 
il merito, o rendere men importanti i benefizii ch' egli rese 
alia scienza. 11 danno ntm ridonderebbe che su coloro, i 



SIEBOLD ON UNICELLULAR PLANTS AND ANIMALS. 113 

quali, schivi alia tatlca dell' osservare, si accontentano della 
autorita del maestro et ne abbraciano indifferentemente, cosi 
le vere scoperte come gli errori. Grazie al cielo V epoca del 
autorita e tramontata, e chi ve si aggioga erri pure conpace, 
che per questo la scienza non avanzera meno, ed anzi da 
quegli errori stessi essa potra trarre vantaggio,"* 

With respect to my views on the organization of the Pro- 
tozoa, published in 1845, 1 have nothing in the main to recall ; 
on the contrary, I have since then had the satisfaction of 
knowing that recognised naturalists and distinguished micro- 
scopists have already sided with me. 

It is, moreover, highly gratifying to notice that at present 
the study of the lower vegetable forms, which as unicellular 
plants correspond to the Protozoa as unicellular animals, is 
exciting a very high interest, and that these hitherto much 
neglected organisms are now finding investigators among 
the most eminent Botanists, by whose labours their position 
in the vegetable world will eventually be decided. 

As one of the most important of the works that have 
appeared of late upon this subject, the following must be 
indicated : — Nageli's ' Genera of Unicellular Algae, physi- 
ologically and systematically considered.'! 

I believe it will not be without interest if I here notice the 
more important points in which, according to Nageli's re- 
searches, the unicellular Algae are distinguished from the 
lower animal forms. As especially worth consideration, I 
would adduce the following expression of Nageli's (p. 2) : — " It 
is to be lamented that of several genera and of many species of 
hitherto known unicellular Algae nothing has been observed 
respecting their propagation, and that consequently not only 
has their systematic position but even their independence as 
unicellular plants remained in doubt." I am satisfied that 
many of Ehrenberg's Infusoria, were their origin and de- 
velopment, as well as their modes of propagation, fully traced, 
would long since have been recognised as vegetable forms ; 
that is to say, as lower forms of Algae. 

For the better appreciation of the exposition given by 
Nageli respecting the organization and vital actions in the 
unicellular Algae, with reference to the vegetable forms con- 
sidered as Infusoria by Ehrenberg, it will be necessary to 
premise a list of those vegetable organisms which have been 
treated by Ehrenberg as Infusoria, and by Nageli as uni- 

* G. Meneghini. Sulla animalita delle Diatomee. Yenezia, 1846, 
p. 172. 

f Gattungen einzelliger Algen physiologisch unci svstematisoh bear- 
beitet von C. Nageli (Zurich, 1849, mit 8. lith Tafi.). 

VOL. 1. I 



114 SIEBOLD ON UNICELLULAR PLANTS AND ANIMALS. 

cellular Alg^ae. Among the eight orders of unicellular plants 
instituted by Nageli, that of the Chroococcace^ contains, in 
Meyer's genus Merismopcedia, Gunium (jlaucum, tranquillum. 
and punctatum, Ehr. The order of the Diatomace^ cor- 
responds to the siliceous Bacillaria, Naviculacea, Echinellea, 
and Lacernata, Ehr, In Nageli's order of the Palmel- 
LACE.E v/e find Artlirodesmus and Tassarthra, Ehr., referred to 
Scenodesmus, Mey., as well as the genus Micrastei'ias, Ehr.. to 
Pediastrum, Kiitz. Lastly, the order DESMiDiACEiE contains 
many unicellular Algae, placed by Ehrenberg under the 
genera Desmidium, Pentasterias, Eiiastrum, and Closterium. 
For part of these Ehrenberg's definition is retained ; but 
others of them are raised to the rank of distinct genera. Thus 
has Nageli from Closterium trahecula, Ehr., formed the genus 
Pleurotcenium, and from Closterium cylindrus, Ehr., the genus 
Dysphinctium ; wliilst a portion of the Desmidese with Pen- 
tasterias have been placed under the genus Phycastriim^ Kiitz. 

According to Nageli (p. 3), the unicellular Algse occur 
either solitary or united into colonies, which readily break up 
into single cells ; or the} .'nay be firmly united by a gelatinous 
envelope, though separated from each other by a gelatinous 
s ubstance, and without any organic connexion ; or they are 
placed singly at the extremities of a branched gelatiniform 
peduncle. Occasionally, also, the cells are firmly connected 
into a parenchyma, as in multicellular plants, in which case 
the connexion breaks up into smaller portions, or even into 
single cells, either not at all or but very seldom. 

With regard to the relation of the unicellular Algae to the uni- 
cellular animals, and the unicellular condition of multicellular 
animals, Nageli (p. 4) thus expresses himself. " The most im- 
portant difference : — that the vegetable cell-membrane contains 
no azote, whilst the animal cell-membrane does — cannot be ap- 
plied, especially in doubtful cases ; the tenuity of the membrane 
not allowing of the investigation. That animals possess the 
power of locomotion but plants not, is, in the first place, in- 
correct, as applied o;enerally, and also here the less admits of 
application, because many unicellular Algae exhibit motion, fre- 
quently very energetic motion (when swarming), whilst the ova 
of multicellular animals are quiescent. The unicellular Algae 
differ from the Infusoria in this, that their membrane and its 
appendages are not motile, and that consequently they have a 
rigid form, whilst the latter, in some instances, change their 
figure, and in others are furnished with motile-cilia. The 
presence of starch in the cell-contents is, further, invariably 
decisive as to the vegetable nature of a cell. The ova of 
multicellular animals, the figure of which is rigid and un- 



SIEBOLD ON UNICELLULAR PLANTS AND ANIMALS. 115 

changeable, may also be recognised as not belonging to the 
unicellular Alga? from the want of colouring matter, which is 
present in all the latter." I shall have an opportunity further 
on of recurring to several of these points, and of entering 
more particularly into them. 

As respects the chemical relation of the cell-contents of 
unicellular Algae, Nageli lays great stress upon the presence 
of colouring matter. This colouring matter is distinguished 
by him as Chlorophijll,Ph.ycochrom, Erythrophyll, and Diatomin. 
The Chlorophyll is of a grass or yellow-green colour, little or 
at all affected by diluted acids and alkalies, and frequently turns 
brownish-green upon the death of the plant.* The Phycochrom 
is verdigris-green or orange, changed into orange by the action 
of diluted acid, and into a brown-yellow by that of diluted 
alkalies. The Erythrophyll presents a red or purple colour, 
not changed by diluted acids, but becoming green on the 
addition of alkalies, and also most usually after death. The 
Diatomin is brownish-yellow, not altered by diluted alkalies, 
but changed into verdigris-green by diluted hydrochloric 
acid, and, for the most part, by death. Together with the 
colouring matter, continues Nageli (p. 9), starch grains, or 
colourless oil-drops, are frequently formed, with the increase 
of which in the persistent cells (dauerzellen) the former 
finally disappears. 

I must here remark, that we can scarcely expect chemistry 
to decide what is animal and what plant, having several times 
been deceived in our hopes in this respect. The non-nitro- 
genous cellulose, which at first sight appears to be an exclu- 
sive attribute of the vegetable, also occurs pretty generally 
disseminated in the animal kingdom, as we learn from the 
researches of C. Schmidt on Cynthia mamillaris, and those of 
Kolliker and Lowig on a great number of the most various 
of the lower animals. Just as little does Chlorophyll ap- 
pear to be exclusively characteristic of the vegetable world, 
since the green granules and vesicles, which occur imbedded 
in the parenchyma of Hydra viridis, of various Turbellariae 
(Hypostomiim viride and Typhloplana viridata, Schm.), and 
of Infusoria (Euglena viridis, Stentor polymorphus, Bursaria 
vernalis, Luxodes bursaria, Sec.), are probably closely allied to 
Chlorophyll, if not identical with it. Erythrophyll also 
might be said to occur in the lower animals, for instance, in 
Leucophrys sanyuinea and Astasia hamatodes, in which latter 
the red colour frequently passes into green, as does the Ery- 
throphyll of unicellular Algae. 

* Vide Cohn. 



116 SIEBOLD ON UNICELLULAR PLANTS AND ANIMALS. 

Another more important circumstance connected with the 
chemical composition of the cell contents, is also noticed by 
Nageli, and wliich relates to the so called red eye-spot of certain 
Infusoria. He saw, for instance (p. 9), in the midst of the 
Chlorophyll of certain unicellular Algae, one or several bright 
red or orange-coloured oil-drops, upon which he remarks upon 
the similarity of these red granules with the red point, which 
occurs in several swarm-spores, for instance in Ulothrix. 
An inspection of Nageli's PI. IV., B. fig. 1-4, will at once 
show the identity of the bright red oil-drops in the quadran- 
gular unicellular Algae Polyedriurn trigonum, tetragonum, 
tetraedricum^ and lobulatian, Nag., as well as in the interesting 
new unicellular Algae, Ophiocytium majus, Nag. (PI. IV., A. 
fig. 2), with the points, so often stated to be eyes by Ehrenberg. 
These are precisely the same red points, as those which 
are met with also in Eudorina, Cklaniidomonas, and Volvox 
Infusoria — which I must declare to be unicellular Algae. 
Very remarkable is Nageli's statement (p. 9), that the chloro- 
phyll in many unicellular Algsc occasionally disappears 
altogether, being transformed into a red or orange-coloured 
oil, a change not always connected with the death of the cells, 
as for instance in Plenrococcus miaiatus. Nag. ; Protococcus 
nivalis, KUtz. ; Palmella miniata, Leibl., &c. 

In almost all the genera in which chlorophyll occurs Nageli 
found (p. 1 1) one or more cidoropliyll-cells, for the most part 
in regular number and disposition, and exhibiting the appear- 
ance of granules or even of nuclei. Nageli satisfied himself 
that these chlorophyll-cells, even from external appearance, are 
the same forms as those which occur in the multicellular algae 
containing chlorophyll, such as Zygnema, Spirogyra, Sphero- 
plea, Conferva, &c. Further investigation perfectly assured 
him of their identity. These chloi'ophyll-cells at first con- 
tained only chlorophyll (that is, mucus coloured by chlorophyll) 
with a delicate membrane. But they seldom remain in this 
condition, starch at a subsequent period becoming developed 
in them, by which the chlorophyll is wholly or in part dis- 
placed. Then there either lie in the chlorophyll-cell one or 
several minute starch-grains, or it becomes almost entirely filled 
with starch, as happens in the Palmellaceae and Desmidiaceae. 
From this it follows that, although the presence of starch, 
as Nageli says, is decisive as to the vegetable nature of a cell, 
this important means of diagnosis does not always admit of 
application, because starch is not found in all stages of the de- 
velopment of those plants wliich might be confounded with 
unicellular animals. 

But to return to these chlorophyll-cells — is it not apparent 



SIEBOLD ON UNICELLULAR PLANTS AND ANIMALS. 117 

that they are the bodies described by Ehrenberg: as the testes? 
To perceive this it is only necessary to compare the various 
figures in Nageli's work wilh Plates X. and XI. of Ehrenberg's 
great work, in which Scenodesmiis, Mey., is figured as Arthro- 
desmus and Tassarthra, and further Pediastrum, Kiitz., as 
Micrasterias. The colourless hollow spaces filled with water, 
observed by Xageli (p. 91, 95, «S:c.) in the above named, as 
well as in many other unicellular Algae, have been regarded as 
gastric cells by Ehrenberg, as is obvious at the first glance, 
whilst the green granular Chlorophyll contents of these \e^e-r 
table organisms, according to Ehrenberg, would have to be 
regarded as ova. In various Desmidiaceae, for instance in 
Pleurofcpnmm, CahcijUndrns, and C/osterhim, Nageli noticed 
several Chlorophyll-cells, frequently arranged in a serial man- 
ner. In Closterium digitus and Moniliferxim^ as Avell as in some 
other Closteria, he olDserved in the centre of the cell a clear 
nuclear-vesicle with an opaque central nudeolus. It is these 
chlorophyll and nuclear cells which Ehrenberg and Eckhardt 
would arbitrarily explain sometimes as a polygastric apparatus, 
sometimes as the male glandular organs of the Closteria. 

The cell-wall in the unicellular Algae, according to Nageli 
(p. 12), exhibits in respect to colour, conformation, and sub- 
stance, the greatest variety. Very frequently it possesses a 
considerable thickness, and in this case may be regarded as 
laminated, the innermost very delicate layer representing the 
true cell-membrane, whilst the external thick layer, more or 
less distinctly defined on the outer side, constitutes an enve- 
lope for the cell. This enveloping membrane consists of 
vegetable gelatine in various stages of condensation. It may 
surround each individual cell, or contain 2, 4, 8, &c. together, 
or even a whole aggregation of cells, as an entire family or 
colony. As forms of Algae furnished with a gelatinous enve- 
lope I may adduce Gonium^ Schizonema, Naunema, and Syncy- 
clia, Ehr. ; to which must he added Eudorina, SphcBrosyra^ 
Chlamidomonas, Pandorina, and Volvox, Ehr. In some cases 
the lamination and thickening of the envelope takes place only 
on one side, whence it assumes the form of a peduncle, at the 
extremity of which the cell is placed, owing to which, when 
longitudinal scission of the cells takes place, a branched pe- 
duncle is produced. With reference to this compare the figures 
of Synedra, Achnanthes, Echinella, Cocconema, and Gonipho- 
?iema, Ehr, Frequently also the cell-membrane exhibits tliick- 
enings, which are sometimes placed towards the interior (in 
the Diatomaceae), sometimes towards the exterior (in Exiastrum 
and Closterium). 

The growth of the unicellular Algae, according to Nageli, 



118 SIEBOLD ON UNICELLULAR PLANTS AND ANIMALS. 

takes place, either with a general expansion of the cell-mem- 
brane or with a unilateral, or point-growth as it is termed. 
The propagation of the unicellular Algce (p. 17) is effected in 
very various ways, by division, by conjugation, by free cell- 
formation, and by abscission of segments, with various modi- 
fications. Of these various modes of propagation discussed 
by Nageli, I will only observe upon those which have refer- 
ence to the Algae described by Elirenberg as Infusoria. 

In the mode of propagation by scission the entire cell-con- 
tents, according to Nageli, become individualised into two 
(rarely four) parts. After the formation of these filial cells the 
mother-cell ceases to exist. Nageli here adduces, as an example, 
the propagation of the Palmellaceae (to which belong several spe- 
cies of Gonium., Ehr,), the Diatomaceae and Desmidiaceae. In 
Euastrum, after the scission has taken place, in each filial cell 
the one half is perfected entirely anew, whence in the younger 
condition this new half is small, almost spherical and colour- 
less. Nageli has shown this mode of propagation in Euastrum 
margaritiferum, Ehr. (p. 118, Tab. VII. A, fig. 2, e); whilst 
we had previously a description of this interesting process of 
division and growth in Staurastmm and Euastrum, by Ralfs 
(Ann. Nat. Hist., vol. 14, 1844, PL VI., VII., and vol. 15, 
1845, Pl.X., XII.) and Focke (Physiol. Stud., Bremen, 1847, 
p. 47, PI. II.). 

Propagation by conjugation occurs in the Desmidia- 
ceae, which Nageli (pp. 17, 18, Tab. VII., A. fig. 6 h) thus 
describes, in Euastrum rupestre, Nag. : — Two individuals are 
placed close together, and push out short processes, which 
meet, and by the absorption of the wall constitute a canal, into 
which the entire contents of the two cells thus connected 
enters, constitutes one mass, and is gradually formed into a 
single cell. Nageli adds, however, that in Closterium this 
act of conjugation proceeds in a different way, which I can 
confirm. In Closterium lunula, according to Morren (Ann. 
d. 8c. Nat., torn. V. 1836 — Botanique, p. 325, pi. 9) the con- 
jugated individuals appear to grow together exactly in the 
way above described ; in Closterium rostratum also, two indi- 
viduals appear to become united by the middle of their body 
(Vid. Focke, 1. c. pi. III. fig. 84-36, and Ralfs, Brit. Desmi- 
dieae, 1848, pi. XXX. fig. 3 c); whilst Closterium DiancB, 
lineatum, striolatum, setaceum, Sec, behave in a totally different 
manner in this process. In these species the middle of the 
cell-membrane dehisces with a transverse fissvire, and the 
entire contents, from two contiguous, opened cells, coalesce 
into a single rounded or angular mass. Sometimes (in Closterium 
lineatum) it is only the two upper and lower halves which thus 



SIEBOLD ON UNICELLULAR PLANTS AND ANIMALS. 119 

coalesce, forming two closely approximated compressed glo- 
bul^l. Relatively to this mode of conjugation I refer to the 
representations given in Ehrenberg, pi. V . and VI., as well as 
in Ralfs, pi. XXIV. to XXX. It remains to he inquired 
whether the green bodies produced bv this conjugation, the 
covering of which, at first very delicate, gradually becomes 
thickened, are to be regarded as spores or as sporangia. I 
have not myself been able to observe what proceeds from the 
green bodies in course of time. According to Monen (o. c. 
p. 329, pi. 10}, however, it would appear that in Closteriiim 
lunula the green spores arising from the conjugation grow 
into a new Closterium after they have emerged from their 
envelope and, like the spores of Vaucheria, move about freely 
in the water. This process, as is truly remarked b}- Focke 
and Nageli, is not in any way one of multiplication, but pro- 
perly a kind of reduction or diminution. I suppose, there- 
fore, that the green bodies produced by the conjugation are 
not in all cases developed into a single Closterium, like spores, 
but that, as in the case of other Algae, such as Yaucheria, 
(Edogonium, there are two sorts of spore formations, and that 
under certain circumstances these green bodies represent a 
germ — capsule or sporangium — in which, by a process of divi- 
sion, several young Closteria come to be perfected. With 
this mode of development, probably, is connected the vesicular 
body, containing sixteen small Closteria, figured by Ralfs 
(pi. XXVII.) as belonging to Closterium acerosum. Accord- 
ing to Jenner (ib. p. 11) the covering of the green bodies in 
Closterium, which are regarded by Ralfs as sporangia, swells 
whilst a mucus is seci'eted within it, and minute Closteria are 
formed, which at last, by their increase, rupture the attenuated 
vesicular covering. \^ hether or no that form of gelatinous 
vesicle, containing eight young Closteria, which, according to 
Focke {op. c. p. 57, pi. III. fig. 27), proceeds, in Closterium 
digitus, from a process of envelopment, belongs to this category, 
I will leave undecided. 

Ehrenberg has proposed {p. c, p. 89) to designate these green 
bodies of the Closteria, produced by conjugation, as double 
buds, and the entire act of conjugation as a double gemmation. 
This designation, however, is quite inapplicable, since in any 
form of gemmation it is impossible that the entire contents of 
a cell, as is the case here, should germinate into the new- 
formed bud. Ehrenberg, moreover, in the exposition of the 
organization and vital processes of the Closteria, perceived their 
similarity with those of the Zygnemaceae {Zggnema, Spirogi/ra, 
Zggogoniiim, 6cc.), which are also propagated by conjugation. 
He says {p. c, p. 99) that were any one readily disposed to 



120 SIEBOLD ON UMCELLULAK PLANTS AND ANIMALS. 

look for similarities, it would be easy to speak of vesiculae 
seminales, oviducts, and testes (in Spirogyj-a) : but al* is 
motionless ; and just as motionless is every thing in the Closteria. 
All those particulars, which, according to Ehrenberg, would 
serve to prove the animality of these organisms, either have no 
existence at all or are of no validity. He adduces four princi- 
pal characters especially (/. c, p. 88), which would exclude 
the Closteria from the vegetable kingdom. 

1. They have spontaneous motion. The slow, turning, and 
at the same time rare movements of the Closteria, present 
no character of spontaneity ; these motions are certainly merely 
the consequence of an active endosmosis and exosraosis, by 
which the water immediately surrounding the Closteria, and 
consequently themselves, are put into motion. 2. That they 
have an opening at each end. But these openings have not 
been seen by any other observer ; the sharp-sighted Focke 
(o. c, p. 55, 60), even, has been unable to perceive any. That 
Eckhardt {o. c, p. 211 ; p. vii., fig. \,rr) should have intro- 
duced these openings into his figure of Closterium acerosum — 
although they have not been observed in that instance, either by 
himself or by Ehrenberg — can decide nothing. 3. That they 
are furnished with conical, wart-like organs, projecting even from 
these two openings, which are in continual motion ; but these 
organs, also, have not been discovered by any other observer. 
According to Ehrenberg, the number of these proboscis-like, 
motile organs is easily computed, since their basal portions, in 
the form of minute, continually moving papillae, may be dis- 
tinctly seen and counted in almost all Closteria. These papillae, 
however, are nothing else than quivering masses of granules, 
in molecular motion, contained in two vesicular spaces. 4. 
Lastly, Ehrenberg refers to the transverse division observed in 
the Closteria, which, according to him, is to be indisputably 
regarded as irreconcilable with the vegetable character. That 
Ehrenberg is here altogether in eiTor, will be admitted by 
any one who has at all studied the lower vegetable world. 
The Closteria, therefore, are not only as rigid as the Zygne- 
mata, but have quite as much right to be regarded as belonging 
to the vegetable kingdom. No part of their body possesses 
that contractility and expansibility which is an attribute of the 
animal body alone. The progressive motion of granules and 
fluids, which has been noticed in Clsoterium by Meyen, 
Dalrymple, Lobarzewski, Focke, and Ralfs, does not proceed 
from any contractile part of the Closterium cell, but corre- 
sponds much more with the circulation exhibited in other 
plant-cells, as in CItara, Vallisneria, and the hairs of the Nettle, 
cScc. But whether this motion of the fluids depends upon an 



SIEBOLD ON UNICELLULAR PLANTS AND ANIMALS. 121 

internal ciliary investment, as asserted by Focke (o. c, p. 56), 
I may be allowed to doubt, as I have never been able to per- 
ceive such cilia in the Closteria ; and my friend A. Braun, 
whose opinion on such a matter is of the utmost value, has 
been equally unsuccessful. Since the Closteria, as well as the 
rest of the Desmidiacese, are certainly plants, it follows that 
conjugation, or zygosis, as a special kind of propagation, does 
not belong to the animal kingdom, unless Kolliker's observa- 
tion, of the coalescence of two individuals of Actinoplirys Sol, 
should be regarded as an analogous process. There is nothing 
contradictory in the notion that such a conjugation should 
exist in Actinoplirys Sol, a protozoon of so simple a kind, 
whose structureless body, according to Kolliker's late researches, 
consists of a homogeneous, contractile substance, without 
mouth, intestine, or other organs. I would, on the other hand, 
ask those who, with Ehrenberg, not only regard the Closteria 
as animals, but are, besides, under the erroneous impression 
that these creatures possess a very complex, motile apparatus, 
polygastric digestive organs, male and female sexual organs — 
I would ask them what becomes of this motile apparatus, — of 
the various stomachs, ovaries, and testes, — when all these parts, 
with the rest of the contents of the two cases which enclose 
these so-termed complete animal organisms, have coalesced in 
the act of conjugation ? 

A third mode of propagation, viz. a free cell-formation, in 
which the contents of the mother-cell are employed as a nutri- 
tive material, in the formation of the filial cells, and, conse- 
quently, in which the death of the mother-cell is involved, 
would appear, according to Nageli (p. 17), to be restricted to 
the orders of the Protococcaceae and Valoniace^. Whether such 
a production of filial cells within a mother-cell does not occur 
in certain Palmellaceae and Desmidiaceae, which have been 
confounded with Infusoria, I must leave as doubtful. 

[To be continued.] 



( 122 ) 
REVIEWS. 



Lectuees on Histology, delivered at the Royal College of Sur- 
geons OF England, in the Session 1850-1. By John Quekett. 
London, Bailliere. 

[Second Notice.] 

Want of space compelled us to defer further notice of Professor 
Quekett's work in our last number. We sliall now make a 
few remarks on that portion devoted to animal histolog}-. 

Those who are less acquainted with vegetable than animal 
tissues will wonder that a larger proportion of this work is 
devoted to plants than to animals. We have already stated 
our opinion that the best introduction to the study of animal 
cells is the study of the cells of plants, and we think in a 
limited course ]\Ir. Quekett has done wisely in thus dwelling 
on the simpler forms of organization. Having said so much 
upon the vegetable histology, our remarks must be rather illus- 
trative than critical on the remaining portion of this volume. 
The following table will serve as a guide to the subjects 
treated in this department : — 

,,,„., , 1 J 1 C Examples : — Walls of cells. Pos- 

"1. Simple membrane : employed alone ^^^ .^^. j . ^^ ^^^^ ^^^^^_ ^ 

or m the foi-mation of compound ^^^j^ ^^^ ^^^^^ Sarcolemma of 

membranes [ j^^gcle, &c. 

„_,.,,. / White and vellow fibrous tissues. 

2. Fibrous tissues \ ^^^^-^^^ ^^^^_ ^^^^^-^ ^-^^^^^ 

„ „ ,, , ^. / Cartilaoie. Adipose tissue. Pis;- 

3. Cellular tissues [ ^^^^^ Grey nervous matter.^ 

. ,, , 11^ / Rudimentary skeleton of inverte- 

4. Sclerous or hard tissues . . . . | ^^^^^_ g^^^^^ ,^^^^1^^ ^^ 

5. Compound membranes : composed j 

of simple membrane, and a layer I "Mucous membrane. Serous and 
of cells of various forms (epithe- > syno\ial membranes. True or 
lium or epidermis), or of areolar I secreting glands, 
tissue and epithelium . . . . ' 

6. Compound tissues : a, composed of 1 

tubes of homogeneous membrane \ Muscle. Xerve. 
containing a peculiar substance . ) 
b. Composed of white fibrous tis- j pibro-cartilaae." 
sues and cartilage j 

The descriptions given of the structure of membrane, of 
areolar tissue, and of yellow fibrous tissue, are all good, and 
contain many original observations. I'he structure of the 
various forms of cartilage is also described with great accuracy. 
Tliere is now no question as to the non-vascularity of these 
tissues, but in a state of disease, the blood-vessels by which 



QUEKETT'S LECTURES ON HISTOLOGY. 123 

they are surrounded increase in size, and render them what 
are called vascular. 

" In a specimen from a diseased joint, which after removal was carefully 
injected, numerous vessels may be observed jiassing through the cartilage ; 
they are derived from the vessels of the shaft, as the articiilar lamella 
being involved in the disease, permits the vessels to pass through it ; they 
proceed in straight lines through the cartilage to the free articular surface 
upon which they form a network, and anastomose with others probably 
derived from the synovial membrane. The sirbject from whom this spe- 
cimen of cartilage was obtained was fifty years of age, and the disease had 
existed for nearly twelve mouths. A prejsaration which belonged to the 
late Mr. Listou, and which he was in the habit of exhibiting in his Lec- 
tures, consists of the head of the tibia, with diseased cartilage attached. 
Not onljr can vessels be seen by the naked eye, passing from the bony 
shaft into the cartilage, in the form of loops, but a rich network may in 
some cases be observed upon a large portion of the articular surface. As far 
as I have been able to learn from examinations of diseased articular carti- 
lages, esjsecially those affected with ulceration, I conclude that the change 
first takes place in the cartilage cells, as is made evident by their becoming 
rounder and much larger in size, and by their contents assuming a different 
character, the nuclei disa]3pearing, and globtiles of oil taking their place. 
In some cases these oil-globules are of very minute size, and the cells then 
appear granular ; as the disease goes on, the cell-walls are absorbed, a 
series of cavities are formed, all the hyaline substance in the neighbour- 
hood becomes more or less fibrous, and ultimately blood-vessels are deve- 
loped in the fibrous tissue." 

There is a series of valuable observations on Enchondroma. 
In order to explain this structure he gives an account of the 
structure. Speaking of the different views entertained on the 
formation of the lacuna?, he says — 

With regard to the formation of the lacunar of bone, two views are 
now entertained by different histologists. The first is that given in the 
' Physiological Anatomy ' of Professors Todd and Bowman, in which it is 
stated that the lacunar are developed from the nuclei of the cartilage-cells : 
the other that of Mr. Tomes, published in ' Todd's Cyclopa?dia,' article 
( Osseous Tissue,' in which it is asserted that the lacuna? are not deve- 
veloped from the nuclei of the cartilage cells, but are cavities left in the 
newly formed bone, from which canaliculi are subsequently developed. 
The last described specimen of enchondroma, however, tends to prove that 
the view entertained by Todd and Bowman is the more correct. 

Of softening of the bones he says — 

In Mollities ossium, there is a deficiency of the earth}' constituent of the 
bone. The change first begins in the lacunae, which become larger and 
larger, and the bone around them more and more transparent ; finally, 
several lacimae unite to form one cavity, which, however, does not long 
remain empty, but is occupied by a soft kind of adipose tissue, so that 
such bones are always extremely thin and full of fat. For this reason, 
Mollities ossium may be considered as an example of the fatty degeneration 
of bone. 

Of all the subjects to which the attention of the inorbid 
anatomist has been directed of late years there is none per- 
haps of more practical importance than that of fatty degenera- 
tion, moi'e especially of the muscular tissue. We are chiefly 



124 QUEKETT'S LECTURES ON HISTOLOGY. 

indebted for our knowledge of this condition of the muscular 
tissue to the labours of Dr. Ormerod and Dr. Richard Quain. 
Mr. Quekett gives a good account of this morbid condition, 
and previous to doing so describes the structure of healthy 
muscular tissue. The following is his account of the 
fasciculi : — 

Tlie fascicuh exhibit transverse and longitudinal stria^, but, in most 
cases, the former are more plainly exhibited than the latter. In some 
animals the fasciculi break up transversely, in others long:itudinally, so 
that, in the one case, we have a series of discs, and in the other numerous 
filaments termed fibrillar. The fasciculi of the eel readily break up into 
discs, whilst those of man and most mammalia commonly separate into 
tibrillaj. If the flat surfaces of the discs be examined, they present a 
granular aspect, which is due to their being made up of the ends of the 
fibrillas ; and, if the fibrilla; be viewed with a power of five hundred 
diameters, each one will exhibit a beaded structure, the part forming the 
bead being a minute portion of muscular substance, termed myoline ; but 
if the power be increased, the masses of myoline will be foimd to be sur- 
rounded by a thin cell-wall. In the muscular substance of the eel, the 
structureless sarcolemma surrounding a fasciculus is readily seen. 

This we believe to be a true account of the muscular tissue, 
and we cannot imagine that an unprejudiced observer, with a 
good instrument, could contort the square masses of myoline 
into a spiral form. Such, however, is the result of some 
recently published researches. On the diseased condition Mr. 
Quekett remarks : — 

" Before fattj'^ degeneration commences in voluntary muscle, the trans- 
verse stria; disajipear ; and I have long known that the first trace of this 
disease is marked by a disturbance of the particles of myoline, which 
appear as so many very minute granules scattered irregularly within the 
sarcolemma, leading one to suppose that the delicate cell around each par- 
ticle had given way, thereby allowing the myoline to escape, and destroying 
all regularity both of the transverse and longitudinal markings. As the 
disease progresses, the myoline is replaced by minute, highly-refracting 
globules of oil, until at last the whole sheath is full of them. 

In a specimen of this diseased condition of muscle from the human 
subject, the transverse strife are visible in the upper part, and a partial 
disturbance of the myoline in the lower ; in another preparation the 
disease has so far advanced that all trace of stria? is completely lost, and 
globules of oil, in this case of nearly equal size, but in others of variable 
diameter, occupy the sarcolemma. The fibres of the heart are very sub- 
ject to fatty degeneration, and for our knowledge of this disease we are, 
in a great measure, indebted to the labours of Dr. Ormerod ; but the sub- 
ject has been lately investigated with great care by Dr. Richard Quain ; 
and in his paper, published in the fifteenth volume of the ' Medico- 
Chirurgical Transactions,' you will find all that is at present known 
respecting it. A very excellent example of fattj^ degeneration of the 
muscular fibres of the heart, is one taken from a man a hundred and three 
years of age, for which I am indebted to the kindness of Dr. Edward 
Smith ; it exliibits the transverse stria? in some parts, but in others these 
arc rephicod by highly-refracting globules of oil. I liavc lately had the 
opportiuiit}' of examining a most interesting case, in which the disease 
was present in the voluntary muscles of the extremities. In one family 



QUEKETT'S LECTURES ON HISTOLOGY. 125 

of nine children, six of whom were girls and three boys, all the girls 
were perfectly healthy, but the boys, on arriving at the age of three or 
four, beirau to lose the iise of their limbs. One of them, the eldest, has 
lately died, and, on examination of the brain and spinal chord, both were 
found to be healthy ; the muscle, however, had not only undergone fatty 
degeneration, but the fasciculi themselves were much diminished in size, 
which would, of course, account for the want of power in the limbs. This 
disease from the first was supposed to be seated in some part of the ner- 
vous system, probably arising from imperfect innervation of the muscle ; 
but the discovery of its real seat will, it is to be hoped, lead to such a 
mode of treatment as may be beneficial to the two afflicted survivors." 

We have yet to discover the causes of this terrible condi- 
tion of the tissues of the human body. That it is brought on 
by want of action in the muscles is shown by its occurrence 
in paralysed limbs and in those muscles of animals which do 
not perform their normal functions. The most fearful seat of 
its attacks is the heart : when once it seizes this organ its 
action is impaired, and frequently sudden death is the result. 
In this case it is probable that the blood is first at fault and 
leads to the abnormal nutrition of the muscular fasciculi. 

In the section on adipose tissue we find a statement of 
some interest, ^ 

" In all works on anatomy and physiology, even of so late a period as 
last year, it is distinctly stated, that adipose tissue exists in invertebrate 
animals ; this, however, I find to be incorrect, and it cost me no small 
amount of labour to prove it. Fat certainly does exist in insects, Crus- 
tacea, and moUusca, but no true adipose cell is ever present ; it could not 
be nourished without its accompanying blood-vessels, and these are not 
found in invertebrata. The tissue resembling adipose tissue usually lie- 
longs to the liver or other glandular organ, and the fat exists in its cells 
in the form of oil. 

In the liver of the larva of a goat moth, Cossus ligniperda, which con- 
sists of a series of cells or vesicles, containing a large number of globules 
of oil ; and acrain, in another specimen, taken from a cockroach, there are 
tubes, also full of oil globules, but in neither case, and not even in the 
Cephalopoda, is the oil contained in adipose cells. 

As soon, however, as we pass the barrier between the invertebrate and 
vertebrate sub-kingdoms, we find that even in the lowest members of the 
class of fishes, true adipose cells occur, and all are doubtless aware, that 
in the liver of the cod, and of many cartilaginous fishes, fat exists in the 
form of oil without any adipose tissue ; — in this particular, the liver 
resembles that of an invertebrate animal." 

The almost universal presence of oil in the tissues of animals 
is an interesting fact, and one the full import of which is not 
perhaps at present well understood. We have here a fruitful 
subject for microscopic research. 

But we must conclude. The publication of these lectures 
will make all who are interested in microscopical investiga- 
tion anxious for further remarks from Mr. Quekett. At pre- 
sent he lias only given the outlines of histological inquiry, and 
much is to be expected from one who so honestly observes and 



126 REPORT OF PATHOLOGICAL SOCIETY. 

gives his opinions. In our notice we have omitted all refer- 
ence to the wood-cuts which accompany the volume, but they 
are very numerous (159 in number), well executed, and all 
original. It is not often nowadays that one gets such a stock 
of new matter to draw upon. All those interested in histology 
will be glad to have this volume in their library. 



PiEPORT OF THE PROCEEDINGS OF THE PATHOLOGICAL SOCIETY OF LONDON. 

Sixth' Session, 1851-1852. 

The number and value of the contributions to microscopic 
pathology in this volume of Reports of the Pathological Society 
are such as fully to justify a notice of it in our Journal. These 
contributions constitute, in fact, a main feature and no little 
part of the book, and add very materially to its interest and 
utility. Their number shows the extent to which microscopi- 
cal investigations of the highest practical importance are carried 
by the rising generation of medical men ; and the manner in 
which they have been carried out, as displayed in this volume, 
is a most satisfactory proofT)f the technical skill and care of 
the observers. It is clear that the gross and coarse pathology 
of former periods, as well as the kindred physiology and 
anatomy of the same times, is rapidly and effectually giving 
way to the more refined analysis for which the microscope, in 
its improved and still improving form, affords the means. 

Amongst the more generally interesting and valuable of 
these contributions we have only space to refer, and that briefly, 
to a few. 

From Dr. W. Jenner we have "An Account of Crimson or 
Hematoid Crystals, and Calcification of the MinuteArteries of the 
Cerebrum " (p. 239) ; "A Description of a case of Cancer in the 
Posterior Mediastinum " (p. 253) ; " Of a very curious case of 
what is here termed Colloid Disease of the Abdominal Viscera " 
(p. 323). Of the microscopical appearances in this case a 
very careful and detailed account is given. Among the inter- 
esting points, Dr. Jenner refers to the close resemblance of 
certain phosphate of lime granules to olein, and to the 
resemblance borne by the fat imbedded in the colloid matter 
to cells. He directs attention especially to the close resem- 
blance — a resemblance so close tliat he could give no visible 
characters whereby the one may be distinguished from the 
other — between the phosphate of lime and fat. These globules, 
which, judging from the eye alone, experienced microscopists 
pronounced to be oil, were dissolved completely in hydro- 
chloric acid. He conceives that the phosphate of lime was 



REPORT OF PATHOLOGICAL SOCIETY. 127 

deposited chiefly in the interior and nuclei of the epithelial 
scales lining the inner surface of the cells or cysts in which 
the colloid matter was contained. A very nearly similar report 
on the same case is given by Dr. R. Quain. From Dr. Jenner 
we have also a "Report on the Microscopic Appearances in a 
Morbid Growth from the Cranial Bones" (p. 416). 

Several of Dr. R. Quain's reports have reference to cases of 
fatty and fibrinous degeneration of the muscular tissue of the 
heart. With the former of these modes of atrophy Dr. R. 
Quain' s name will always be intimately cormected ; and we 
need not say that what he may state on the subject is always 
worthy of attention. 

He also gives an account (p. 247) of a " Case of Malignant 
Tumour in the Brain," with reference to which it is remarked 
that 

" the extremely close resemblance which this tumour bore in its general 
appearance to an old apoplectic effusion was a remarkable fact well worth 
attention, and the result showed how very valuable is the aid of the micro- 
scope in deteiTuining the nature of these and similar lesions." 

In a case (p. 254) in which the rare combination of encepha- 
loid tumour (in the anterior mediastinum) and tubercle was 
met with, Dr. R. Quain gives the following Report on the 
Microscopic Characters of the diseased Tissues : — 

" Enceplialoid Mass. " Tuberculous Deposit. 

" 1. On section of a pearly-white " 1. Of a pale j-ellow or buft'colour, 

colour ; spotted freely \\ith vascu- not presenting any appearance of 

larity and with apparently eifused blood or blood-vessels. 
blood. 

" 2. Of solid (elastic) consistence, " 2. In some portions solid and 
but friable, yielding, on gentle pres- tough, in others of a cheesy con- 
sure, a quantity of viscous pearly- sistence, and in others of that of 
coloured fluid or juice. thick cream ; the solid parts not 

affording fluid or juice on pressure. 

" 3. With the microscope found " 3. XVith the microscope found 
to consist of a great nmnber of cells to consist of cells, granular par- 
enclosed in large meshes, formed by tides, and fragments of broken-up 
the interlacement of bundles of a fibres ; also to contain some fine fi- 
filamentous tissue, sid generis. The laments, disposed without arrange- 
cells are rather larger than blood ment, and evidently derived from 
corpuscles, are of all shapes, but the lung texture. The cells, which 
generally spherical, and contain are mostly spherical, are smaller 
from one to five nucleoli. These than those from the encephaloid 
are rendered more distinct by acetic mass, and contain apparently more 
acid. Few cells contain distinct numerous and much smaller gra- 
nuclei. There are also numerous nules. These, as in the latter, are 
compound granule or mulberry cells, rendered more distinct by acetic 
and in many parts oily particles. acid. Oily particles are seen, more 
Blood-vessels and blood-globules especially in the softened matter, 
abound. Neither blood-globules nor vessels 

are seen." 



128 REPORT OF PATHOLOGICAL SOCIETY. 

In a case of fatty degeneration of the heart (p. 263), and in 
which rupture of that organ took place, the affection appears 
to have been local or circumscribed, the muscular fibre in 
other parts of the heart being in a remarkably healthy condition. 
The local degeneration or atrophy was evidently connected 
with a diseased condition of a branch of the coronary artery 
distributed to this part of the heart. Dr. Baly reports another 
case of rupture of the heart consequent upon fatty degenera- 
tion, and in this case also, the alteration seemed to be more 
local than general ; but the condition of the coronary arteries 
is not adverted to. Fatty degeneration was present in some of 
the cerebral vessels in the same case. In another case of rup- 
tured heart, with local fatty degeneration, recorded by Dr. 
Quain, the anterior branch of the coronary artery, leading 
directly to the disease, was seen to be greatly ossified, and, 
about the middle of its course, completely obstructed. 

Dr. Bence Jones reports a case in which Sarcina veiitriculi 
was found in the urine of a boy. In the present case it seems 
pretty clear that this was accidental, and that the Sarcina 
really came from the stomach, but at the same time we would 
observe, that it does not appear to be possible to account for the 
presence of Sarcina in the urine in all cases in the same way. 
In the cases recorded by Heller (Archiv. d. C hemic, u. Mikro- 
skopie. Heft 4, 1847, and Heft 1, neue Folge, p. 30, 1852) 
there seems every reason for the belief that the Sarcina was 
produced in the urine itself. In the latter of the cases de- 
scribed by Heller the Sarcina occurred not merely mixed 
with other sediments, but in such quantity as to form a loose, 
white deposit an inch in height, composed wholly of the 
Sarcina, or with a slight admixture of carbonate of lime. It 
is interesting that in all these cases of Sarcina in the urine 
recorded by Dr. Heller there were symptoms indicative of 
cerebral or other nervous lesion. Dr. J. H. Bennett, in his 
Lectures on Clinical Medicine (p. 214, J 851), notices a case 
related by Dr. Mackay. 

Microscopical observations on the so-termed serous cysts in 
the kidney are afforded by Drs. Brinton and Bristowe and by 
Dr. Bence Jones, who examined their contents chemically. 
These observations, however, leave the vexata questio of the 
genesis of the cysts very much as it was. 

Dr. Bristowe assigns reasons (pp. 380-1) for the conclusion 
that they cannot be Malpighian bodies (" at least, not healthy 
ones," he oddly adds), which do not appear to us altogether so 
coo-ent as he would seem to think them ; and that they are 
not dilated tubuli he thinks is sufficiently shown by the cir- 
cumstance that he has never seen a cyst continuous with a 



REPORT OF PATHOLOGICAL SOCIETY. 129 

tube — a condition, we should iinaginc, not likely to occur, 
seeing that the complete occlusion of the tube on each side is 
indispensable to the formation of the shut cyst. He also 
dismisses the notion of their being "fresh formations arising 
from cytoblasts" as untenai)le ; and he is consequently obliged 
to confess that he is unprepared to say how these cysts arise. 

In the next case (pp. 381-2), which is reported upon by 
Drs. Brinton and Bristowe, it would appear that the nucroscopic 
cysts differed in some respects from those in the former: they 
were much less uniform in size — sometimes solitary and some- 
times clustered : they could be readily isolated and moved about 
the field of the microscope. They varied greatly in magnitude, 
the smallest being little larger than renal epithelial cells, the 
largest about the size of Malpighian bodies. The observa- 
tions of Drs. Brinton and Bristowe would seem to have been 
limited in great measure, though not entirely, to the minute 
microscopic cysts. Dr. Bence Jones refers more particularly 
to the larger ones. In the contents of these he was unable to 
discover any of the elements of urine, nor could any epithelial 
lining be detected. It is left to be inferred from this, at 
least we piesume so, tliat these large cysts could not be dilated 
tubuli. But again, this conclusion seems to have been drawn 
hastily. The strongest point in the argument is perhaps the 
absence of epithelium on the inner surface of the cyst But 
the force of this circumstance, perhaps not in itself of such 
very great importance, is, at all events, much invalidated by 
the certain fact that these cysts do occasionally exhibit an 
epithelial lining. Perhaps they must be examined in a verj'^ 
fresh state to show it ; but that such a lining does sometimes 
exist is within our own observaticm. The truth of tlie matter 
after all may be this : tliat the serous cysts are of different 
kinds ; that some, as in Dr. Bristowe's first case, are due to 
dilated Malpighian capsules ; that others, as the smaller ones 
in the second case, originate in dilated epithelial cells ; and 
lastly, that the larger ones are dilated tubuli, that is, in their 
advanced condition. They may liave originally commenced 
in one of the second class. This opinion, which has hmg 
appeared to us likely to afford a more satisfactory explanaticm 
of these cysts than one more exclusive can do, we are glad to 
find coincides with that of Kolliker (Manual of Human 
Histology, pp. 477-8), wlio also fully confirms Dr. Johnson's 
view by an observation of his own. 

Our space will merely allow us to refer to Mr. Toynbee's 
valuable contribution to the knowledge of Tubercle (p. 3S5) ; 
and to Dr. Bristowe's account of " A Malignant Disease of a 
Cystic Ovary" (p. 404, with plate) ; as well as to Mr. 

VOL. 1. K 



130 LEUCOCYTHEMTA, OR WHITE CELL-BLOOD. 

Quekett's " Comparative view of the Condition of the various 
Muscles in three cases of Non-Conjjenital Club-foot" — all 
more or less instances of atrophy. With reference to the 
figures (pi. xii.) belonging to this paper, we should much like 
to have had Mr. Quekett's explanation of the appearance pre- 
sented by fig. 2. Were not such a thing almost impossible, 
one might deem that Dr. Barry's contorted views on the struc- 
ture of muscular fibre had found confirmation to some extent 
in the hands of the Professor of Histology of the Royal Col- 
lege of Surgeons. 



Leucocythemia, or White-Cell Blood, in Eelation to the Physiology and 
Pathology of the Lymphatic Glandular System. By John Hughes 
Bennett, M.D., F.K.S.E. Edinburgh : Sutherland and Knox. 

No branch of science has been benefited by the employ- 
ment of the microscope so much as physiology. So great, in 
fact, have been the advantages accruing to the study of vege- 
table and animal histology by the aid of this instrument, that 
it is regarded by some scientific observers as exclusively the 
property of this branch of science. Although physiology had 
latterly made rapid strides by the aid of chemistry, especially 
when applied in the investigation of the first and last facts of 
a given series of phenomena, it still failed to supply the 
means of examining those intervening links in the chain which 
occurred within the organism of plants and animals. In 
revealing the great fact that animal and vegetable tissues are 
principally composed of cells, and that all the functions they 
exhibit are the result of the properties of individual cells, the 
microscope laid the foundation of a true science of life. 
Since its first application in this direction, the physiology of 
plants and animals has become a new science ; the old sys- 
tems are gradually retiring, and everywhere more accurate and 
profounder views of the nature of life and organization are 
supplanting doctrines which had become venerable only for 
the want of the means of testing their truth. At the same 
time that the microscope is furnishing the means for a more 
philosophic study of the functions of plants and animals, it 
promises to render their study more definitely available for 
the practical ends which the medical practitioner has in view. 
The success of empiiical practice, and the encouragement 
given to irregular systems of treating disease, have not arisen 
so much from the ignorance of the public, as from the com- 
paratively feeble assistance which the prevailing doctrines of 
physiology and theories of disease were capable of affording 



LEUCOCYTHEMIA, OR WHITE-CELL BLOOD. 131 

to the most loarnod physician. This time is passing by, and 
the microscope, in conjunction with a chemistry which, if it 
cannot imitate, is at least beginning to trace accurately the 
changes undergone by the elements contained in a living cell, 
is hastening the time when physiology shall pass from the 
speculative to the certain sciences, and medicine no longer 
remain a conjectural art. Already has it pointed out the 
differences between diseased and healthy tissues, and afforded 
a means of diagnosis which did not previously exist. The 
secretions, the contents of the viscera, and above all the blood, 
can be examined with an accuracy which seems to promise a 
sufficient means for working out the phenomena of health and 
disease. 

These general remarks have naturally occurred as intro- 
ductory to the notice of a book which describes a disor- 
dei-ed condition of the blood, which could only be detected 
by the microscope, and which presents us with inferences 
from the conditions thus observed, having a wide range of 
application, and embracing the discussion of most important 
generalizations. The condition of the blood described is 
called by Dr. Bennett Leiicocythemia (Xsukos- kltos aT/xa), and 
consists essentially in the presence of a larger number than 
usual of white cells amongst the red globules of the blood. 
The work contains a record of thirty-five cases in which this 
condition was observed before or after death. The mode of 
ascertaining the condition of the blood whilst the patient was 
living was to puncture slightly the end of the finger with a 
lancet. On placing a drop of the blood thus procured under 
a microscope, the coloured corpuscles were found to collect 
together in rolls, whilst the colourless corpuscles filled up the 
intervening space. Acetic acid was found to dissolve up the 
coloured bodies, and to render the colourless ones very trans- 
parent. The latter, thus treated, presented a nucleus, in some 
consisting of a single round or oval body, but in the majority 
presenting two, three, or even four granules, each having a 
depression in its centre. Sometimes the nucleus was cres- 
centic, or in the form of a horseshoe. These appearances 
were presented in most of the cases examined. It is difhcult 
to estimate the proportions of the corpuscles, l)ut Dr. Bennett 
states that, when all the meshes or interspaces between the 
coloured corpuscles are filled up with colourless ones, the 
latter may be estimated at one third. 

After detailing the cases with great accuracy, the author 
enters into a variety of general considerations, to some of 
which we would draw attention. One of the most remarkable 
facts in connection with this condition of the blood is the 

K 2 



132 LEUCOCYTHEMIA, OR WHITE CELL-HLOOD. 

almost constant presence of disease of the spleen and lymph- 
atic glands. Of nineteen cases in Avhich the body was 
examined after death, the spleen was enlarged in sixteen, and 
the lymphatic glands were more or less diseased in eleven. 
The chapter on the diseased condition of bodies presenting 
the white-cell blood is followed by a discussion on the 
relation existing between the colourless and coloured cor- 
puscles of the blood, and the origin and destination of the 
blood corpuscles. We cannot follow the author through this 
argument, but give his conclusions : — 

" 1. That the blood corpuscles of vertebrate animals are originally 
formed in the lymphatic glandular system, and that the gveat majority of 
them, on joining the circulation, become coloured in a manner that is as 
yet imexplained. Hence the blood may be considered as a secretion from 
the Ij'mphatic glands, although in the higher animals that secretion only 
becomes fully formed al'icr it has received colour by exposure to oxygen in 
the lungs. 

" 2. That, in mammalia, the lymphatic glandular system is composed 
of the spleen, thymus, thjToid, supra-renal, pituitary, pineal, and lymph- 
atic glands. 

" 3. That, in fishes, reptiles, and birds, the coloured blood corpuscles 
are nucleated cells, originating in these glands : but that, in mammals, they 
are free nuclei, sometimes derived as such from the glands ; at others, de- 
veloped within colourless cells. 

" 4. That, in certain hypertrophies of the lymphatic glands, their cell 
elements ai'e multiplied to an unusual extent, and under such circumstances 
find their way into the blood, and constitutes an increase in the number of 
its colourless cells. This is leucocythemia. 

" 5. That the solution of the blood corpuscles, conjoined with the effete 
matter derived from the secondarj- digestion of tlie tissues, which is not 
converted into albumen, constitutes blood fibrin." — p. llli. 

Dr. Bennett then enters upon the consideration of various 
patliological conditions, on whicli his investigations on the 
nature of white-cell blood seem to throw light. By far the 
most important of these is inflammation. It is a prevalent 
notion tdat the accumulation of the colourless corpuscles 
within some of the smaller vessels is an essential condition 
of this important pathological condition. Tlie discovery of 
white-cell blood, in whicli the colourless corpuscles of the 
body abound, must be regarded as opposed to this view. 
Dr. Bennett says — 

" On the other hand, every known fact convinces me, and the progress 
of science only adds strength to my convictions, that we must ascribe the 
iiltimatc cause of inflammation to a derangement of those forces which re- 
gulate the nutritive powers of the economy, and that the only correct defi- 
nition of inflammation itself is — an exudation of the normal liquor san- 
guinis. It is in vain that physiologists seek in the alterations of the ves- 
sels on the one hand, or in morbid changes of the blood on the other, for 
the primary cause of this imi)ortant condition. P'acts prove that both are 
more or less affected, and also show that neither the one change nor the 
other, nor the two combined, constitute iiiflanniiation. The vital proi;ertics 



HANDBOOK OF HUMAN HISTOLOGY, 133 

of the tibisucs (understanditig bj' these the unknown conditions necessary 
for carr\-ini;; on tlie nutritive processes) are in all such cases deranged, and 
such alteration is the cause of the changes which liave been referred to, 
and not the effect." — p. 115. 

The work is accompanied with two coloured lithographs 
and a large number of woodcuts illustrative of the condition 
of the blood globules. It will be read with interest by the 
medical man, and is a capital instance of the value of the 
microscope in t!ie practice of medicine, not only as affording 
the facts on which alone sound physiological theories can be 
based, l:»ut as the only means of discriminating between many 
very different pathological conditions. 



Handbuch dee Gewebe-lehre des jMexschen FiiR Aerzte und Studi- 
RENDE, niit 313 Holzschnitten. Von A. Kolliker, Prof. d. Anat. u. 
Physiol, in Wurzburg. (Handbook of Human Histology, for Prac- 
titioners and Students, with 313 Woodcuts. By Prof. A. Kolliker.) 

" Meuicixe has arrived at such a stage that Microscopical Anatomy ap- 
pears to form its foundation, as much as the anatomy of the organs and 
systems ; and a thorough study of Physiology and Pathological Anatomy 
is impossible without an exact knowled.L;;e of the most miniite fonnal ele- 
ments. It becomes then the duty of those who cultivate tins field of 
science not only to communicate their observations to their fellow-workers 
and to those who are more profoundly acquainted with medicine, but to 
enable all those who are concernt'd with the study of Man, and especially 
students and practitioners, to profit thereby. The present work seeks to 
pcrlorm this task by giving as condensed as possible a view of the rela- 
tions of the elementary parts of the body and of the more minute structure 
of the or':^ans ; avoidin'j;; all polemical discussions, with the exception of a 
few of the more important points as yet subjudice, and leaving the history 
of the science completely in the backgroimd ; but, on the other hand, en- 
tering as fully as possible into those points which bear upon Physiology, 
Pathological Anatomy, and Comparative Histology." 

Such is Professor Kolliker's preface to the very admirable 
work in which he exhibits the result of his manifold and 
long-continued microscopical researches into the structure of 
the human body. Nor has Professor Kolliker's performance 
fallen short of these his professed intenti(ms. Any one who 
will carefully study the work will, we think, agree with us, 
that since the publication of Henle's ' Allgemeine Anatomic,' 
ten years ago, no hist<jlogical manual has appeared in any 
country* at all comparable with it for exact research in 
matters of detail, for completeness as a whole, for breadth of 
view, and last, but by no means least, for the conscientious 
care with which the author has in almost every case made 

* Our readers will think wo ha\e forgotten the admirable work of Todd 
and Bowman ; but it has never been completed. 



134 HANDBOOK OF HUMAN HISTOLOGY. 

himself acquainted with the literature of his subject. We 
mention this good quality particularly, because we have been 
surprised to meet with one or two defects, arising, as we think, 
from the Professor's having overlooked good work performed 
on this side of tlie Channel. The chapter on the Blood, 
pp. 565-5S4, for instance, seems to us to be the weakest in 
the book ; and we can hardly think it would have been so, had 
Professor Kolliker sufficiently studied the observations, pub- 
lished in this country so long ago as 1845, by Mr. Wharton 
Jones,* in a memoir which we consider to be one of the most 
important contributions ever made to our knowledge of this 
subject. 

We have unfortunately no space to enter into a detailed 
criticism, but we must remark that Wharton Jones has here 
demonstrated ( 958) that the " stellate lymph corpuscles," 
figured by Kolliker i fig. '220), are formed by a peculiar shoot- 
ing out of the wall of the lymph corpuscle, and not by any 
" exit of their contents." (Kolliker, note, p. 565.) Professor 
Kolliker is one of those who have paid most attention to the 
phenomena of contraction presented by simple cell membranes, 
but he has forgotten to mention one of its most extraordinary 
and earliest discovered instances — that Amoeba-like motion of 
the " colourless corpuscle," described by Wharton Jones, in 
the blood of the skate, frog, «Scc. (loc, cit., § 9-24), and 
quite readily visible by any one who looks carefully after it 
even in the human " colourless corpuscle." 

There is yet a piocess wliich Professor Kolliker takes pretty 
much for granted — we refer to a supposed natural division of 
the nucleus of the colourless corpuscle, and to the consequent 
occurrence of multiple and biscuit-shaped nuclei ; but any 
belief in which, must, we think, be greatly shaken by the 
perusal of §§ 29-30, 63-66, of Wharton Jones's Memoir, 
and by the repetition of his experiments (we have often 
repeated them in man) be completely destroyed. Certain it 
is, that the more gradually and carefully the re-agent is 
applied, the more certain is one to find the colourless cor- 
puscles of the blood with only circular nuclei, while, if it be 
applied suddenly and concentrated, one is almost equally 
cerfciin to find them with nuclei of every irregularity of 
shape, from biscuit-shaj^ed to mulljerry-sha])ed. 

Finally, considering that " the origin of tlie blood corpuscles 
after birtli and in the adult " is " one of tlie most obscure 
portions of the history of the blood-cell " (Kolliker, p. 581), we 

* riiiloso]iliical 'I'ransactioiis, 1846, Part II., " The Blood Corpuscle 
considcvcd in its diflcicnt Phases of Dcvelo[)mcnt in the Animal Scries." 



STRUCTURE OF MUSCULAR FIBRE. 135 

think that the very strong arguments, not to say the complete 
demonstration, contained in the memoir so often referred to, 
that the blood corpuscle is the free nucleus of the " colour- 
less corpuscle," deserved grave consideration, and, at any rate, 
should not Iiave been passed over in silence. Professor Kolli- 
ker's own view, that the red corpuscles are the small lymph 
corpuscles (Cliylus Korperchen), which have lost their nucleus 
and become coloured, is, we think, totally untenable. 

We regret to have had to find any fault with a work which 
is, in so many respects, faultless. It is only our sense of the 
great influence it is likely to have which has compelled us 
to do such violence to our feelings of gratitude towards its 
author. 



Memoires de la Societe de PJiysique et d^Histoire Naturelle de 
Geneve. Tome xii. ler Partie, pp. 169. 1849. 



1. Microscopic Obsekvations on the Structure of Muscular Fibre. 
By Dr. J. L. Prevost, 

No'nviTHSTANDiNG the profession with which the author com- 
mences, of his intention to give a more precise description of 
muscular fibre than had previously appeared, we are un- 
able to perceive that this laudable object has been in the 
slightest degree carried out. There is little or nothing in the 
paper worthy of notice, and the illustrations are equally use- 
less. It is only surprising that so lately as 1849 such a de- 
scription of the mode of origin of muscular fibre could have 
appeared as this : — ■ 

" Fibrine is the principal constituent of muscles. Soluble in the blood, 
it circulates with it, and is eventually deposited on the cellular frame- 
work, which determines the form and direction of the muscular fibres. 
This is seen very well in the embryo of the vertebrata. At first the vo- 
luntary muscles present rows of cellular cylinders, along which run nu- 
merous blood-vessels ; shortly afterwards these cylinders are filled with 
organized fibrine." 

He describes some experiments upon portions of muscle 
taken from the leg of Carahus auratus, in which the muscle 
was exposed to the action of solutions of strychnine, hydrocy- 
anic acid, sulphate of morphia, and chlorine. According to 
him the isolated muscles of this insect will continue to ex- 
hibit contractile movements for twenty minutes or more when 
immersed in water. Strychnine, after producing violent con- 
tractions and elongations, (!) destroys this irritability in about 
ten minutes. Prussic acid acts, according to M. Prevost, 
more quickly, but the contractility even under its influence 



136 BRITISH ZOOPHYTES— MARINE POLYZOA. 

lasts for a minute or more, and morphia does not put it to 
sleep under eight minutes ; whilst a solution of chlorine in 
water, strang-e to say, acts as an invigorating agent, for under 
its agency the movements are said to have persisted for half 
an hour or more. 

It is needless to remark upon such experimental results as 
these. 

2. Note Relative aux Apparences Microscopiques des Cheveux 
HuMAixs ET DES PoiLS d'Animaux. By M. A. MORIN. 

A murder having been committed some months previously 
on the person of a forest-guard, in the Pays de Gex, M. 
Morin and another were charged with the duty of determin- 
ing whether a hair, three lines long, found on the handle of an 
axe, taken in the house of a suspected person, were that of a 
man or of some animal. 

The author adverts to a previous case of an analogous kind, 
which occurred in 1837, and, according to him, is the only 
one ; it is reported by M. Olivier d' Angers. 

AI. Olivier appears to have distinguished human hair from 
that of the horse and ox, simply by the existence in the former 
of a central canal. Notwithstanding this absurd notion, 
which could only have arisen in an optical delusion, his deci- 
sion happened hy chance to be correct, 

M. Morin, who appears to be equally ignorant of any suffi- 
cient distinction between the hairs of man and certain do- 
mestic animals, also arrived at what was probably a correct 
result. The only distinctive character upon which he seems 
to lay any stress consists in this, — that, according to him, the 
human hair possesses a general tiansparency, which is wanting 
in the others ! Neither of these cases, though the decision of 
the question in both was probably right, should be cited as 
an instance of the useful application of the microscope to 
medico-judicial inquiries. M. Morin gives several figures of 
different hairs, but tliey are coarse and useless. 



A Popular Htstory ok ]')R1tish Zoophytes. By the Rev. D. Lands- 
ROROUGH, D.D. Loiulon : Iieeve and Co. 

A Catalogue of Marike Poltzoa in the Collection of the British Mu- 
seum. Part I. By George Bukk, F.B.8. Printed hy Order of the 
Trustees. 1852. 

These two works, though not of large si>^e, are yet of interest to 
a large class of microscopic observers, and especially to those 
who devote attention to the attractive subject of marine zoophy- 



ATLAS OF PHYSIOLOGICAL CHEMISTKY. 137 

tolog'y. 'I iie first of them, which forms one of Mr. Reeve's 
well-known series of popular works on Natural History, is from 
the welcome pen of Dr. Landsboroujih. The arrangement 
followed by tlie author is that of Dr. Johnston, to whose 
classical and most valuable work on the same subject* he 
confesses himself to be mainly indebted for the substance of 
his own compendium. Several new species, however, are 
descrilied, and the figures are for the most part original and 
from nature. These figures exhibit numerous species, both in 
the natural size and magnified ; they have been remarkably well 
etched on stone by Mr. Achilles. The setond work, of which 
we here have only the first part, contains sixty-eight plates — 
containing magnified figures, drawn to a scale, of about 123 
spe( ies, constituting a portion only of the Celleporina of Dr. 
Johnston, or of what the author (Mr. Busk) terms the " Cheilo- 
stomata." It also contains an arrangement of the species of 
this numerous and much-neglected class, differing in some 
respects from any former one ; and short, descriptive, and dis- 
tinctive chara.cters of the various Orders, Sub-oi'ders, Families, 
Genera, and Species, and the habitats of each species. The 
work, when complete, will afford, to a certain extent, a means 
for a more accurate comparison between the different species, 
and a more satisfactory ^ iew of their distribution on tlie sur- 
face of the earth, than has hitherto been possible. We defer 
a more detailed notice of this catalogue until such completion 
has been effected, here merely observing that the present part 
contains the Families Catenicellidae — Salicornariadae — Cel- 
lulariadae — Scrupariadse — Farciminariadae — Gemellariadae — 
Cabereadae — Bicellariadae — and Flustradae. 



Atlas der Physiologischen Chemie. (Atlas of Physiological Chemistry.) 
By Dr. Otto Funke. Leijisic : Engelmanu. Loudun : "\\'illiams 
and Norgate. 

'J^iiis work consists of fifteen plates, with six microscopical 
subjects on each plate, and is intended as a su})plement to Dr. 
Lehniann's admirable Manual of Physiological Chemistry. 
'J he Englisli reader alread}^ possesses a translation of this work 
by Dr. Day, published by the Cavendish Society. The pub- 
lication of this Atlas will not only be acceptable to those who 
possess that work, but to all who are interested in microsco- 
pical chemistry. A reference to Dr. Lel.mann's work will 
( learly show that there are many products of great interest in 

* A History of llio P>ritish Zoophytes. By George Johnston, M.D., 
LL.D. 2nd edit. 1847. Van Voorst. 



138 CURIOSITIES OF THE MICROSCOPE. 

the blood and secretions of the human body which, although they 
have a complicated chemical structure, are yet easily recognised 
by means of the microscope. A knowledge of the forms which 
these substances assume will be easily acquired by means of 
the present Atlas. These illustrations, however, are not con- 
fined to chemical compounds, but wherever particular condi- 
tions of the solids or fluids of the body have been referred to 
by Dr. Lehmarm, needing the microscope for their elucidation, 
they have been given by Dr. Funke. The plates are litho- 
graphed, and, wherever colour is required, it has been done 
from the stone, and we may point to them as good examples 
of what may be accomplished for the illustration of micro- 
scopic objects by these processes. 



Curiosities of the Microscope. By the Rev. Jos. H. Wythes, M.D. 
Philadelphia : Lindsay and Blakiston. 

In our last number we noticed a work by Dr. Wythes, in 
which we pointed out a number of plagiarisms, without the 
slightest acknowledgment. We are sorry to have to announce 
that the present work is, if possible, a still worse instance of 
the appropriation of the literary property of others. The 
design of this work, like that of the last, is good, but, as in 
that work, it is badly carried out, and scarcely a sentence can 
claim to be regarded as original. The work consists of de- 
scriptions of microscopic objects, with plates, for the use of 
young people. The principal subject treated of is the family 
of Infusoria, and the plates and descriptions are directly copied 
from a work by Miss Agnes Catlow, published by Messrs. 
Reeve and Benham, with the title of ' Drops of Water.' On 
account of the proved plagiarism of this part of the work, we 
understand the publishers of Miss Catlow's book have been 
enabled to prevent the further sale of the American work. 
We have felt it our duty to call attention to this gross violation 
of the rights of authorship, and regret to find that it has been 
perpetrated by a gentleman who claims by his titles to belong 
to both the medical and clerical professions. 



MEMORANDA. 139 



NOTES AND CORRESPONDENCE. 



On Microscopical Ite-ascents. — The list of re-agents, and 
tlie instructions for using them, given in your last number, 
cannot but be useful to all who are commencing the study of 
the Microscope. There is, however, one point connected with 
these re-agents of such vast importance that I cannot forbear 
urging it on your notice, in the hope that you may devote 
some portion of your space to its discussion and elucidation : 
I refer to the various and unusual crystalline forms which 
many re-agents assume when they meet under the microscope. 
Without a knowledge of these singular facts, and without a 
perfect recognition of the crystalline forms, errors in micro- 
chemical investigations cannot but occur. I will illustrate my 
meaning by a few examples, which must be familiar to many 
observers, but which I do not happen to have seen noticed. 

1. Liquor potassa^ is a common re-agent in microscopy. 
Itself a liquid, and its principal combination with carbonic 
acid being a highly deliquescent salt, no agent could be 
thought more free from possible fallacy. If, however, a drop 
of potash be allowed to evaporate on a slip of glass, crystals 
appear, some of which are of a very remarkable form. They 
are chiefly six-sided tables, exactly like cystine. When in 
quantity they are often crowded together, as the cystine 
plates are, and sometimes exhibit a similar nucleus-like body 
in their centres. If a larger portion of liquor potassae be put 
in a watch-glass, in a few weeks' time a mass of dry crystals 
appear, which are chiefly composed of innumerable needles 
aggregated together. 

I at first thought that these crystals were the result of im- 
purities, but on procuring some perfectly pure potash, the 
same as that which was used by Mr. Graham in his diffusion- 
experiments, the same phenomena were observed. 

The crystals thus formed appear to be a carbonate of 
potash, but I have been unable to form them from the usual 
carbonates. I have tested these crystals carefully for nitric 
acid, without detecting any, and for sulphuric acid, a trace 
of which can sometimes, but not always, be found. They 
effervesce with acids, and of course dissolve in water, but 
not with extreme readiness, that is to say, not like a deli- 
quescent salt. 



140 MEMORANDA. 

1 need hardly remark, how thoroughly any one working 
with liquor potassee might be deceived if he were not aware 
of these facts. 

2. Every one knows that acetate of potash is a very deli- 
quescent salt, and that, when it is formed under the micro- 
scope, it generally soon disappears. But acetate of potash, 
forming by the union of its constituents, and crystallizing out 
of acetic acid, is (as long as acid is present") a stable salt, 
which has a crystalline form, widely differing from acetate of 
potash crystallizing out of water. And (a most remarkable 
circumstance) the form of the acetate of potash varies accord- 
ing to the strength of the acid out of which it crystallizes, so 
that there is a great range of phenomena, which miglit tend 
to mislead even a very careful observer. As the crystals 
forming in liquor potassae often resemble cystine, so the 
acetate of potash, forming out of strong acid, resembles, to a 
certain extent, some form of uric acid. F'or, mixed up with 
other forms, long dagger-like or lancet-shaped crystals are 
seen, which, if we were on the qui vive for uric acid, might 
very well deceive us. I need not say how frequently in 
micro-chemical research these two common re-agents may 
meet on one slip of glass. 

3. The re-action of iodine again is a most important one. 
The rule is, that iodine colours starch blue ; but in certain 
albuminous mixtures, as pointed out lately by Majendie at 
the College of France, iodine loses this property, and, as far 
as starch is concerned, is temporarily indetectible. This 
dirticulty must be d(me away with before iodine can be used 
without fear in micro-chemistry. 

4. One more singular instance of modification of pro- 
])erties from admixture may be mentioned. Acetate of pot- 
ash and chloride of calcium are separately highly deliques- 
cent salts. Mix together acetic acid, liquor potassae, and 
chloride of calcium, so as to have some slight excess of acetic 
acid, the mixture will evaporate to a solid, dry, crystalline mass. 
Now, in complex fluids, such as blood, exudations, and even 
in urine, these four re-agents may very easily occur together 
under the microscope, and the resulting crystals may mislead. 
I do not know that a mistake from this cause has ever actu- 
ally arisen, but its possibility is evident. 

I might narrate various other curious re-actions, had I time 
or did your space permit. Enough has been said to show 
that in micro-chemistry we require a thorough examination of 
the behaviour of our re-agents among themselves, before we 
bring them into play on other bodies. Such an examination 
1 should hope some of your young energetic readers will take 



MEMORANDA. 141 

up, and it is for the purpose of" inciting some one to do so 
that 1 have written this letter. It is evident also that not 
only micro-chemistry will benefit by this inquiry, but that 
crystallography may thus be studied under (as far as I know) 
a different aspect, and that not only the microscopist, but 
even the chemist may acquire, from the phenomena of crys- 
tallization under unusual circumstances, some increase of the 
present knowledge of physical and chemical re-actions. — 
E. A. Parkes, M.D., Harley Street, Cavendish Square. 

On Thin ttlass-CoYcrs. — Most persons who have treated 
themselves to the luxury of a microscopic object-glass of large 
aperture and high power, have experienced the disappoint- 
ment of finding that some pet object, whose structure they 
expected to see finely developed, has been permanently 
mounted under a cover so thick as to put vision with such a 
glass entirely out of the question. 

The reason of this is, not that very thin glass cannot be 
procured, or that it is particularly expensive (for the increased 
quantity of the thinner material contained in the same weight 
fully compensates for the increased price), but that the deli- 
cate manipulation required in cutting and cleaning it induces 
those who mount objects for sale, as well as most others, to 
prefer a glass of greater thickness. 

It is desirable that no object which may require to be sub- 
mitted to a higher power than a quarter-inch object-glass of 
75° aperture should ever be mounted under a cover thicker 
than 1-1 40th (,007) of an inch. Indeed, if the aperture of 
the object-glass exceeds 120°, the best thickness for the cover 
is I -250th (,004) of an inch. Glass of this thickness can 
easily be cut with a good writing diamond when laid on a 
piece of plate-glass, as proposed by Mr. Warington, and de- 
scribed in Mr. Quekett's Treatise on the Microscope, second 
edition, p. 265 ; but in the cleaning, a great many pieces are 
usually broken. The following method, which is often used 
by chemists for cleansing test-tubes, 6cc., I have found to suc- 
ceed : — Place the covers in a small cup or glass, and pour 
over them enough strong sulphuric acid (common oil of vitriol) 
to wet every part of them. Let them stand for a day or two ; 
then wash tliem in repeated waters until all the acid is re- 
moved. Stretch a clean cambric handkerchief tig];t over any 
flat surface, such as a piece of plate-glass or a druggist's ])iil- 
slab, and lay the glasses on it a few at a time. By rubbing 
them very gently with another handkerchief on tlie finger, 
they may be dried without using sufficient force to break 
them. They should then be removed to a clean box with 



142 MEMORANDA. 

forceps, and carefully kept from dust, and from contact with 
the fingers. Before, however, they have undergone this 
careful cleansing, the covers should be sorted according to 
their thickness, the readiest method of doing which is by 
means of an instrument made by Mr. Ross, called a " lever of 
contact." It consists of a long, slender index, having a pro- 
jecting touch near the centre of motion, which is kept in con- 
tact with a plane surface by means of a spring. When a piece 
of glass is inserted under the touch, the index points to the 
thickness on a graduated arc. In this way covers may be 
sorted very rapidly. 

The same thing may be accomplished less readily by 
merely placing a fragment in the pliers, with the edge up- 
wards, under the microscope, armed with an inch object-glass 
and an eye-piece micrometer, and measuring its thickness in 
the usual way. 

When an object is already mounted, neither of these 
methods is applicable ; but the thickness of the covering- 
glass may then be ascertained very nearly by having the head 
of the fine adjusting screw graduated, and ascertaining the 
value of the graduations on a piece of glass previously mea- 
sured by either of the former methods. For example, the 
screw-head in my microscope is divided into ten ; and to 
focus from the lower to the upper surface of a piece of glass 
I -100th of an inch thick, takes one turn and six-tenths, or 
16 divisions; consequently, it would take 1600 divisions to 
focus through an inch of similar glass. Therefore, if I divide 
1 600 by the number of divisions through which the screw has 
been moved, I shall obtain the thickness in the vulgar frac- 
tion of an inch, or the decimal expression of the same quan- 
tity by dividing the number of divisions by 1600. Unless 
the glass has been carefully wiped, some specks will be 
readily found by which to adjust the focus. — George Jackson, 
Church Street^ Sjntalfields. 

Achromatic Gas-Iiainp for the Microscope. — das as a 

sourceof light presents great advantages over oil and spirit, on 
account of cleanliness, being ever ready for use, and affording a 
perfect control over the flame ; but when the ordinary gas- 
lamps are used for the purpose of illuminating the field of 
the microscope a yellow glaring light is given, alike injurious 
to the eye and the definition of the object under examina- 
tion. To correct these evils, I have arranged a lamp which 
is also otherwise useful to the microscopist. It consists of 
a stage. A, supported by a tube and socket, sliding on an 
upright rod rising from the stand. This carries an Argand 



MEMORANDA. 



U3 



burner, B ; a metal cone, C, rises to the level of the burner, 
and is about one-eia^hth of an inch from its outer margin. 




This arrangement gives a bright cylindrical flame. The 
bottom of the stage, B, is covered with wire gauze, to cut off 
irregular currents of air, and thus secures a steady Jiame. Over 
the burner is placed a Leblond's blue glass chimney, D, 
This corrects the colour of the flame to a certain extent ; but 
it is still further rectified by a disc of bluish black neutral 
tint glass, E, fitted in a tube, F, attached obliquely to the 
shield, G. G is a half cylinder of metal, which serves to 
shield the eyes from all extraneous light, but may be rotated 
on the stage. A, by aid of the ivory knob, H, when the full 
light from the flame is desired. A metallic reflector, I, fixed 
on its support, so as to be parallel to E, concentrates the 
light. By the combination of the two glasses, D and E, the 
yellow rays of the flame are absorbed, and the arrangement 
affords a soft white light which maybe still further improved 
by receiving the rays on a concave mirror, backed with 
plaster of Paris, L ; and where a very strong light is re- 
quired, a condensing lens should be interposed between the 
lamp and the mirror of the microscope. By removing the 



1J4 MEMOIJANUA. 

shield, G, and bringing the shade, M, over the burner, it 
may be used as a reading-lamp. A retort ring, N, supports 
a water-bath, O, or a wrought-iron plate, P, 6 inches by 2^ 
inches, both used in mounting objects. The stop-cock, Q, 
gives the means of regulating the flame. The screw, R, 
clamps the lamp-head at any height desired. The lamp may 
be attached to any gas supply, by vulcanized India-rubber 
tubing. 

This lamp might be used for many other purposes, as for 
minute dissections, watchmaking, engraving, &c. A Le- 
blond's chimney, in combination with an outer glass globe of 
a bluish black neutral tint, might be with advantage used 
in our dwellings. — Samuel Highley, Jun., .32, Fleet. Street. 

(^old-Btiist under the Mieroscope. — Mr. Warren De la Rue 
has sent us some specimens of African gold dust, mounted 
for microscopic examination by Mr. James Nasmyth, of Patri- 
croft, Manchester. Under an inch object-glass they present 
an interesting o))ject. Each grain has the irregular, smooth, 
worn surface that is so characteristic of the larger nuggets, 
and whilst looking at them, as Mr. Nasmyth observes, one is 
almost tempted " to put out the hand and gral) one or two 
from so rich a field." The examination proves that the same 
causes have been at work in producing the smaller grain 
which have acted upon the large nuggets. 

IiifuNuria in morbid di^tcliai'i^es. — At one of the weekly 
meetings of the London Medical Society, Mr. Weedon Cooke 
exhibited some purulent discharge from a cancerous tongue, 
which presented a large number of Infusoria. They were 
of two kinds, apj)arently belonging to the families of Monadina? 
and Vibriones. Mr. Cooke stated he had not seen animal- 
cules in (ancerous discharges from other parts. Infusoria are 
not uncommon in diseased secretions from the mouth and in 
the decomposing food that collects about the teeth, and it is 
probable tlicse animalcules were not specially connected with 
the diseased product in which they were found. 

Med A II I Hill leu I es in ftiod. — M. Montagne, in a letter to 
M. I''h)urens, which was read before the Academy of Sciences 
in Paris, gives an account of the oc(;urren( e of the Monas 
jmxlu/io.sa of IChronberg, in various kinds of food, in a district 
near Rouen in iMance, in .July hist. Pastry, fruit, vegetables, 
and other arti( h's of food sudch-nly exliiljited an intense car- 
iiiiiic ()r hriglit rose cohmr, wliicli was found to depend on a 
gchitinous substance, whicli, when examined under the mi- 
<rosrope, presented the appearances of the animalcule de- 



MEMORANDA. . 145 

scribed by Ehrenberg. M. Montagne says he has succeeded 
in propagating this animalcule by means of boiled rice. 

On the Occurrence of STucIeolated red Corpuscles in 
Human Bioofl. — In the examination of some human blood, 
made for the purpose more especially of observing the 
changes in form occasionally assumed by the Protean colour- 
less or lymph corpuscles, 1 was fortunate enough to meet 
with a very distinct and clearly defined nucleolated red cor- 
puscle, to employ the term used by Mr. Wharton Jones in 
his very valuable Memoir on the Blood in the ' Philosophical 
Transactions' (1845). This form of corpuscle, though stated 
by Mr. VV. Jones to be common in the blood of the horse and 
elephant, appears to have occurred to his observation but 
once, and then doubtfully, in that of man. The observation 
now recorded, therefore, of what must be regarded as a rare 
phenomenon, and which was confirmed at the time by my 
friend Mr. Huxley, may be considered of some interest and 
of importance, towards the confirmation of Mr. W. Jones's 
views respecting the nature of the blood corpuscle. The 
nuclear portion of the corpuscle in question was rather 
smaller than most of the free blood discs, but not so small as 
some of them, nor apparently much, if at all, below the mean 
size of those bodies. It is to be regretted, that on my pro- 
ceeding to take its dimensions with greater accuracy than by 
mere comparison with the surrounding blood discs, the object 
was lost. No others of a similar kind could be detected on 
prolonged examination of the same blood, which, it may be 
observed, was taken about an hour after his breakfast from a 
young and vigorous man. The observation was made on the 
4th December, — George Busk. 

The Polyg'astrica larval states of ^Vorms. — In the May 

number of ' Silliman's Journal ' there is a letter from Professor 
Agassiz to Mr. Dana, in which he makes the following re- 
marks : — " You may remember a paper I read at the meeting 
at Cambridge (America), in August, 1849, in which I showed 
that the embryo which is hatched from the egg of a Planaria 
is a genuine polygastric animalcule of the genus Paranieciinn 
as now characterised by Ehrenberg. In Steenstrup's work 
on alternate generation * you find that in the extraordinary 
succession of alternate generations ending with the production 
of Cercaria and its metamorphosis into Distoma a link 
was wanting — the knowledge of the young hatched from the 
e^^ of Distoma. The deficiency I can now fill. It is another 
Infusorium — a genuine Opalina. With such facts before us 

* Translated by the Ray Society. 
VOL. I. L 



146 . MEMORANDA. 

there is no longer any doubt left respecting the character of 
all these Polygastrica : they are the earliest larval condition of 
worms. And since I have ascertained that the Vorticellae are 
true Bryozoa, and botanists claim the Anentera as Algae, 
there is not a single type of these microscopic beings left which 
hereafter can be considered as a class by itself in the animal 
kingdom." 

Ear-i;vax. — Most persons are familiar with the fact that 
the wax occasionally accumulates in the external auditory pas- 
sage to such an extent as to produce partial deafness. I was 
under the impression that the pellet usually found was actu- 
ally ceruminous, until very recently, when an opportunity was 
afforded me of examining a small accumulation microscopically. 
I found it to be composed entirely of a mueedinous fungus and 
a minute portion of epithelium. On maceration in ether and 
subsequent evaporation, I could find no evidence whatcAcr of 
the existence of wax. I shall be glad to know whether other 
observers have noticed the same fact. If so, it is interesting as 
explaining the comparative rarity of the accumulation, and in 
general its small liability to return. — T. Inman, M.D., Liver- 
pool. 

Microscopical Inquiries. — Will you kindly inform me in 
your forthcoming number what kind of camera is best for 
drawing from the microscope ; and whether any particular 
description of photographic paper is better suited than an- 
other for the same purpose? 

I think that photographic pictures of microscopic objects 
would be exceedingly valuable, as we should not then be 
liable to error in our representations of what we see, in conse- 
(juence of any preconceived notions of the subject, which I 
think is at present the case to some extent. — J. I, 

[We shall be glad to insert queries such as the above, and 
to receive answers from our correspondents. We are not clear 
whether our correspondent inquires about a camera for ordi- 
nary drawing or for photography. — Eds.] 



( 147 ) 



PROCEEDINGS OF SOCIETIES. 



Microscopical Society of London. 1852. 

October 27. — George Busk, Esq., in the Chair. A paper by 
Joseph Delves, Esq., " On the Application of Photography to the 
Representation of Microscopic Objects," was read. After some pre- 
liminary observations the author proceeded to describe his method 
by stating, that the only arrangement necessary for the purposes of 
Photography is the addition to the microscope of a dark chamber, 
similar to that of the camera obscura, having at one end an aperture 
for the insertion of the eyepiece and of the compound body, and at 
the other a groove for carrying the ground glass plate. This dark 
chamber should not exceed 18 inches in length, as if longer the light 
transmitted by the object glass is diffused over too large a surface, 
and the picture is faint and unsatisfactory. Another advantage is, 
that pictures taken at this distance are in size very nearly equal to 
the object as seen in the microscope. The time of producing the 
pictures varies from five to fifteen seconds. 

He also made some remarks upon the mode of manipulating, and 
concluded by calling attention to some very beautiful specimens, 
which were exhibited, and afterwards presented to the Society. 

November 24. — George Jackson, Esq., in the Chair. Messrs. 
Redwood, Brown, Osborne, Ludlow, and Tischmacher were elected 
members. A Paper was read by R. Hodgson, Esq., " On the Re- 
production and Delineation of Microscopic Forms." The object of 
the Paper was to point out the value of the camera lucida for deli- 
neating microscopic forms as compared with the various photographic 
processes. In the discussion which followed the reading of this 
Paper, Mr. De la Rue, Mr. Bowerbank, and Mr. Hogg expressed 
their conviction, that by photography more accurate and more avail- 
able pictures of microscopic objects would one day be made than 
could be done by the hand. Mr. Shadbolt exhibited a very accurate 
photograph, which he had succeeded in obtaining by means of a 
camphine lamp. From this he thought that persons who had not 
time to work at photography by day and natural light, would be 
able to accomplish this object at night by artificial light. 

December 29. — George Jackson, Esq., in the chair. A paper 
was read by Mr. Busk on the Starch Granule, in which he showed, 
in accordance with the views of Leeuwenhoek and Martens, that its 
structure was vesicular. The granides were examined under the 
action of heat, sulphuric acid, and otlier reagents. Mr. Brook ex- 
hibited a moveable arm for changing object-glasses without a screw, 
and a portable stand for examining objects with a pocket-glass. 

l2 



148 PROCEEDINGS OF SOCIETIES.— OBITUARY, 

Pathological Society. 

At the meeting in November, Dr. Richard Quain brought forward 
two cases of Leucocythemia. The first was the case of a man thirty- 
seven years oki, who had enlargement of the spleen and liver, 
also of the glands of the neck and axilla, and other parts of the body. 
The white cells in the blood were very numerous, and contained 
nuclei. The second case was that of a woman, forty-five years of 
age, who also had enlargement of the liver and spleen. 



OBITUARY. 

Ix Dr. Algernon Mantell, who died on the 10th of November, 
the science of microscopy has lost a most ardent cultivator. He 
early perceived the value of the microscope as an instrument of 
geological research, and many of his papers indicate how success- 
fully he used this instrument. One of his works, entitled ' Thoughts 
on Animalcules,' was devoted to a subject entirely microscopical, 
and displays an intimate knowledge of the structure and habits of 
many of the recent species of Infusoria. As a scientific teacher 
and cultivator of geology and its kindred sciences, Dr. Mantell's 
loss will be severely felt. 



( 149 ) 



DESCRIPTION OF PLATE II. 

On the Embryogeny of Orchis mascula, hy Dr. Cobhold. 

The letters indicate the same in all the figures : — l, bract ; p, peduncle ; 
ov, ovula ; n, nucleus ; se, secundine ; pr, primine ; pt, pollen tube ; 
es, embryo-sac ; ev, embryonic vesicles. 



Fig, 

1. Flower of Orchis mascula prior to impregnation. 

2.) 

3. 1 Stages of growth of ovula before the period of fertilization (mag. 200 

4. ( diamet.). 

5.) 

6. Condition of the ovarium and peduncle at the time of impregnation. 

7. Portion of the same (mag. 2;^ diamet.). 

8. Fullj^ developed ovule (mag. 200 diamet.). 

Mode of union between the pollen tube and embryo sac (figs. 9 and 10 
mag. 250 diamet.). 



io!l 

ll.j 



On Melicerta ringens, by P. H. Gosse, Esq. 

Figs. 12 to 27. — Details of the Anatomy and Development of Melicerta 
riugeas. 

12. The animal exti-acted from its tube viewed sidewise. 

13. The animal within its tube, expanded (the lower half omitted). 

14. The same viewed in front ; ventral aspect. 

15. The same ; dorsal aspect. 

16. The gizzard, in situ. 

17. One jaw. 

18. The gizzard under pressure. 

19. The jaws under pressure. 

20.1 One jaw, as in situ and under pressure; the parts lettered alike, for 
21./ comparison. 

22. A peculiar gland in the foot. 

23. A ridged egg. 

24. A smooth egg. 

25. The young newly hatched ; ventral aspect. 

26. The same, dorsal aspect. 

27. The same, commencing its tube ; vertical aspect. 



On Melicerta ringens, by Professor Williamson. 

28. Mouth of Melicerta, showing the continuity of the lower ciliated ridge, 
with the arches at the side of the mouth. 



.Jom^Ami^^ %IL 



TV St 








S«l<>VV«.ii¥ HBunCu.)'! 



-^i. 



no 



S^.JpL^.%y. ^IIV 




B>ak^«w.I^.L<i«i<iL 



DESCRIPTION OF PLATE IV. 

On a Cyst upon the Olfactory Nerve of a Horse, hy J. B. Simonds, Esq, 
Fig. 
1. The cyst containing a crystal of oxalate of lime. — a. Bell-shaped spot 
in interior of cyst. — h, A moveable mass of granular matter. 



On ihe Development of Tubularia indivisa, hy J. R. Mummery, Esq. 

16, 17. Fully developed bead of Tuhularia indivisa, loaded with repro- 
ductive capsules. 

13. Xewly-formed head. 

14. The same, showing arrangement of ovaries. 

12. Internal surface of head (the oral tentacles removed), exhibiting 
twelve lines radiating from base of cavity, and corresponding with 
external ovaries. 

15. Base of two marginal tentacles. 

18. A group of reproductive ca^jsules from the full-grown head, in several 
co-existing stages of development. 

2, 3, 4, ?>, 6. Progress in the extrication of young Tubularia, at intervals 
of one hour. 

8. A young animal of the ellipsoidal form. 
7a. Ditto, of the discoidal variety. 

7b. The same, thirty-six hours after emerging from the capsule. 
7c. The empty capsule. 

10. The specimen, fig. 8 — three days after — still free. 

9. Ditto, on the fifth day, having affixed itself at base. 

11. The young animal at the expiration of six weeks ; the head having 

now acquired a pale rose tint, and the peripheral tentacles increased 
to sixteen. 



DESCRIPTION OF PLATE V. 

On Ihe Structure and Development of Vol vox globator, hy Geo. Busk, Esq. 

1. Embryo Voluox, in which the contents are divided into four segments. 

2. Ditto, in which segmentation has proceeded to the formation of 

numerous segments, each furnished with several amylaceous 
spherules. 

3. Ditto, after segmentation is completed, but before the appearance of 

cilia. 
3.* Portion of the edge of an embryo Vohox viewed in the equatorial 
plane, showing the cilia perforating the outer tunic, but not passing 
beyond the external gelatinous (?) envelope. 

4. The same when tested by solution of iodine, 

5. Portion of the edge of mature IWi'ox (var. vulgaris) viewed in the 

equatorial plane and representing three zoospores in situ. The 
faint lines between indicate the limits of the gelatinous envelope 
of each zoospore, the junctions of which are indicated by the 
hexagonal areas of Mr, Williamson. (These intermediate lines have 
been added to the figure since the original production of the paper.) 

6. Mature zoospores, undergoing " deliquescence." 

7. Zoospores in which the contractile vacuole is still present. 

8. "Winter spores" of V. aureus, a, in the earlier state; b, when 

matured. 

9. Contents of mature winter spore, affected by solution of iodine, 

a, amylaceous granules ; h, yellow oil, 

10. More highly magnified view of a winter spore compressed, to show 

the double tiuiic, 

11. The same crushed, and treated with iodine and sulphuric aci<l. 

12. A portion of the edge, to show the granular fluid (as rendered so by 

iodine) between the outer and inner tunics, a, granular fluid ; 
h, interior of spore. 

13. Portion of wall of Hjiharosira Volvox. 

14. Zoospoi-es in different stages of development, a, one fully divided, 

seen on the side ; h, the same viewed from above ; c, one in which 

segmentation has proceeded only to the second division. 
If) 
Ki 

17. ) Series of changes occurring in the hydropical condition of zoospores, 
18. 
19. 
20. More highly magnified view of the same — where there is apparently 

a second coat in process of being thrown oft' from the central mass 

of i)r(^toplasm. 

22'! A series of changes undergone by the same zoos]iorcs in the course of 
no' ( twenty-four hours. 

Fig. 22 shows llie i)artial dropsy of tliu cell, but which did not 
])r()ceed furtlicr. 

24. Professor Williamson's hexagonal arcolation. 

25. Ditto under iodine. 

20. A])pcarance assumed by the zoospores in the early state, where, owing 
to abundant nutrition, tlic ([uautity of protoplasm is very abundant. 
'I'liis form gradually jiasscs into the ordinary, and it is in this state 
tliat tlie contractile spaces are most advantageously to be sougl)t. 

27. Shows the situation of the contractih; vacuole in a connecting band. 



^^^ J(p<x^%aM'V: 




^J J J 






^m^B ^ 







9.Buak.aA TvEI«iWMt.u!r: 




: I 



J^Jhar^ffo-.M.VF 




fCWdd T<fln>liBt. 901% 



B<4k'WK.%Hlfaac.0af 



DESCRIPTION OF PLATE VI. 

O71 the Structure of Volvox globator, hy Professor W. (J. Williamson. 

The same letters of reference are employed throughout to indicate the 
same structures. 

r>' I Cells of the stellate var. of Volvox in diftereut stages of the con- 
o'> traction of the protoplasmic threads. 0, outer cell-wall; &, pro- 
. * I toplasm ; e, connecting threads ; (/, cilia. 

5. Section of Volvox, with its ciliated parietal cells. /, vesicles in 

which the ciliated gemm«e are developed. Two of the gemma) 
seen out of focus. 

6. Young gemma ruptured by pressure, h, detached protoplasms ; 

/, vesicles mthin which the gemma is developed ; c, protoplasmic 
membranes of three segments of the gemma, h, granular and 
mucilaginous matter escaping from the ruptured segments. 

7. Portion of a Volvox mounted in glycerine and viewed obliquely. 

a, cell-walls ; h, protoplasms ; c c, protoplasmic membranes ; e, col- 
lapsed connecting threads. 

8. Similar cells, in which the protoplasmic membrane is more distended. 

References as before. 

9. Specimen in which the threads appear to traverse the intercellular 

spaces. References as before. 

10. Ordinary appearance of the var., with spherical protoplasms. 

11. Specimen of the same mounted in glycerine. 

12. Probable section of living Volvox. d, superficial pellicle. 

13. Probable section of fig. 11. 

14 \ 

-.f-'t Sections of figs. 1-4, after being mounted in glycerine. 

16. Detached cells from the same, viewed superficially. 

17. Similar specimen, in which the cells are invisible — the protoplasmic 

membranes alone beina; seen. 



( 149 ) 



ORIGINAL COMMUNICATIONS. 



On the Development of the Teeth^ and on the Nature and 
Import of NasmytKs " Persistent Capsule.'^ By Thomas 
H. Huxley, F.R.S. 

I AM desirous of setting forth in the course of the following 
pages, as concisely as may be, the principal results to which 
I have been lately led in the course of working over the 
development of the human and of some other teeth. I have 
directed my investigations, not to the general phenomena of 
dentition, our knowledge of the course of which, firmly 
established many years ago by Professor Goodsir, has not 
been affected, so far as I am aware, by any subsequent in- 
vestigations, but to those points of structure and develop- 
ment upon which every writer, from the time of John Hunter 
to the present, seems to have formed, with more or less 
plausibility, an opinion of his own, different from that of all 
others. 

I must suppose such a knowledge of the general course of 
development of the teeth as may be found in the ordinary 
hand-books of physiology — my limits allowing no unnecessary 
disquisition — and proceed at once to the questions whose 
discussion I am about to attempt. These are, firstly : What 
are the three structures which are concerned in the develop- 
ment of the teeth, viz., the pulp, the capsule, and the enamel 
organ, morphologically, or in relation to the parts of the 
mucous membrane from which they are developed ? 

Secondly : What is the relation of the dentine, the enamel, 
and the cement, to these organs ? 

Thirdly : What is the I'elation of the histological elements 
which enter into the composition of the soft parts, to the 
dentine, enamel, and cement, which are formed from, or 
within them. 

These questions, I think, involve all the essential points 
connected with the teeth. Having endeavoured to answer 
them, I shall inquire with what other organs of the animal 
the teeth correspond. 

1. The nature of the pulp, the capsule, and the enamel organ, 
with relation to the tnucous membrane from which they are de- 
veloped. 

The teeth are developed in two ways, which are, however, 

VOL. 1. M 



150 HUXLEY ON THE DEVELOPMENT OF THE TEETH. 

mere varieties of the same mode in the animal kingdom.* In 
the first, which may be typified by the Mackerel and the 
Frog, the pulp is never free, but fiom the first is included 
within the capsule, seeming to sink down as fast as it grows. 

In the other the pulp projects freely at one period above 
the surface of the mucous membrane, becoming subsequently 
included within a capsule formed by the involution of the 
latter : a marked instance of this mode of development occurs 
in the human subject. The Skate offers a sort of interme- 
diate stage. 

If the thick and opaque, coloured, mucous membrane of 
the jaw of the jMackerel be torn away, and the alveolar edge 
of the jaw be then examined with a low power, minute germs 
will be seen to be imbedded in the substance of the jaw, 
among the large, fully-formed teeth. One of the smallest of 
those which I examined is figured at PI. III., fig. 10. It was 
an oval mass, about l-60th of an inch in long diameter ; its 
upper part was roofed as it were by the epithelium of the 
gum ; its sides were constituted by a continuation of the base- 
ment membrane of the mucous membrane of the mouth ; 
within this was a homogeneous substance, containing nu- 
merous oval or rounded nuclei, about l-5000th of an inch in 
diameter, and continuous with the lowest layer of the epithe- 
lium of the mouth. In the centre appeared a large conical 
mass, nearly as long as the sac, the proper tooth pulp. 
Pointed above, it widened below, and then gradually con- 
tracted again, so as to form an almost hemispherical lower 
extremity, which was united to the base of the sac by a 
narrow neck. In the upper part of the papilla the proper 
dental tissues had already begun to make tlieir appearance ; 
but below, a delicate membrane formed its outer boundary, and 
this passed directly into the basement membrane of the sac. 

It is clear then, that in this case the papilla is wholly a 
process of the derm (or that which in a mucous membrane 
corresponds to it) outwards, while the sac is a process in- 
wards of the same structure ; and that tlie homogeneous sub- 
stance, with its imbedded nuclei between the two, corresponds 
with the epidermis or epithelium. 

In the Frog the same relations essentially hold good ; the 
young teeth are here developed in minute sacs, which lie at 
the bottom of the dental groove in the upper jaw. I could 
never detect any free-projecting pulps (notliing, therefore, 

* For tlio ]iuri)0.scs of the present examination I have taken the Rkato, 
the Mackerel, the Frog, tlie (.'alf, and Man, as accessihle si)ecimens of each 
of the great divisions of animals possessing teeth. 



HUXLEY ON THE DEVELOPMENT OF THE TEETH. 151 

corresponding' to the papillary stage in the human tooth), but 
the smallest and youngest rudiments of the teetli 1 found were 
oval or rounded sacs, l-180th of an inch long, containing- an 
oval papilla, about one-fourth shorter. Externally, these were 
bounded by a strong structureless basement membrane, which 
enclosed a homogeneous substance, containing nuclei in its 
cavities. Ttiese were rounded, and very close togetlier, next to 
the basement membrane, but became transversely elongated in 
the inner layers and next to the pulp. This last was bounded 
by a structureless membrane, which at its narrow base became 
continuous with the basement membrane of the capsule. 

In the Frog, then, the relations of the pulp and of the cap- 
sule are the same as in the Mackerel. 

In the Skate, as is well known,* the young teeth are 
developed in longitudinal rows within a deep fold of the 
mucous membrane of the mouth, behind the jaw. So far as 
my examinations go, however, I find that this is not a 
mere simple fold, such as it has been described to be ; but its 
two walls behave just in the same manner as those of the 
primitive dental groove in man — that is, they become closely 
united in lines perpendicular to the direction of the jaw, so 
that partitions are formed between every two rows of teeth — 
transverse partitions again stretch between the separate teeth 
of each row, but these did not appear to me to be complete, 
terminating by an arcuated border below (fig. 11). Each longi- 
tudinal canal therefore answers to a single elongated mammalian 
follicle, or to that prolongation of the alveolar groove from 
which the posterior permanent molars are fonned in man {see 
Goodsir), only the process does not go so far as in this case, 
the separate capsules remaining imperfect anteriorly and 
posteriorly. The lateral walls of the capsule, however, seem 
to me to have as much (or as little) " organic connexion with 
the pulp and attachment to its base " as in man, and the pro- 
cess seems to correspond with something- more tlian the " first 
and transitory papillary stage of the development of the mam- 
malian teeth." f 

Each pulp is invested by a very distinct basement mem- 
brane, whose continuity with that of the mucous membrane 
of the follicle is very obvious. The epithelium of the follicle 
forms a thick layer, which sometimes, when tlie upper wall 
is stripped back, adheres to it — sometimes remains as a cap 

■*- See TMakc's ' Essay,' &c. 1801, hi which the essential pectiliarities of 
the (levclopnient of the teeth in the sliark and skate, and tlieir mode of 
advance, are very weU pointed ont. He refers to Herissant and Si-allanzani 
as havinti anticipated him. 

t See Owen's ' Od()nton;rai)]iy,' ]'. li'. 

M 2 



152 HUXLEY ON THE DEVELOPMENT OF THE TEETH. 

investing the papilla. Even when the latter does not take 
place, shreds of the epithelium frequently adhere to the 
papilla in the form of irregular, more or less cylindrical 
nucleated cells ; as often, however, the papilla, whether any 
of the proper tooth suhstances be formed or not, has nothing 
adherent to it, l)ut presents a perfectly smooth sharp edge. 
Other portions of tlie epithelium, particularly towards the 
bottom of the follicles, are more or less altered and irregular, 
frequentli/ assuming tJieformofa stellate tissue. 

In the Skate, then, the follicle is an involution of the derm, the 
papilla is a process of it, and the epithelium between the two 
becomes metamorphosed sometimes into a peculiar stellate 
tissue. The same essential relations prevail as before. 

In Man, some confusion has prevailed with regard to the 
homology of the various component parts of the tooth sac, 
though they might be readily enough deduced from the mode 
of development of the sac ; however, it is, I think, not at all * 
difficult to obtain perfect demonstration upon this subject. 

II a young tooth capsule be opened (say of a foetus at the 
seventh month), whatever care may be exercised, it will 
always be found (Hunter, Bichat) that a space filled with a 
fluid exists between the inner surface of the capsule and the 
outer surface of the pulp — tJte two are perfectly free from all 
adherence to one another — the only substance between them, 
besides the fluid, being a more or less abundant whitish matter 
which sometimes adheres to the one and sometimes to the 
other (.>e(? Goodsir, /. c). 

If the tooth be very young, a structureless membrane, the 
m preformativa of Riischkow (the basement membrane of 
Bowman), may be traced over the whole surface of the pulp, 
or ii calcific depositicm have already commenced, it may be 
found readily enough at any rate in the lower unossified part ; 
and it is not at all diflicult to trace this in perfect continuity 
on tlu; walls of the capsule — in fact into its basement mem- 
brane. The best way of seeing this is by detaching the whole 
sac from its alveolus, and then, laying it carefully open 
in a watch-glass, turn the capsule carefully back, transfer 
the whole to a glass plate, and cover it with a piece of thin 
glass. The continuity of the basement membrane of the pulp 
with that of the capsule is now evident enough under the 
microscope. 

The wall of the capsule is often folded, and sometimes I 
liavc" noticed villous processes, suc^h as those described as 
vascular by Dr. Sharpey.* Not unfrequently the basement 

» So<! also rioodsir, /. r. p. 17. In a cliiM al birth " the interior of 
tlie sac had a villous, lii;j;lily vascular apiicarancc, like a ])Ortion of 



HUXLEY ON THE DEVELOPMENT OF THE TEETH. 153 

membrane of the capsule is quite naked, but I liave sometimes 
observed a lining of short cylindrical nucleated epithelium 
cells upon it. 

I have said that a whitish substance lies between the base- 
ment membrane of the pulp and that of the capsule. It is 
delicate and friable, but frecjuentlj forms a more resisting 
layer towards the pulp. On this surface I have found it to 
be composed of a layer of elongated, more or less cylindrical 
epithelium cells 1-lOOOth of an inch in length, with or 
without nuclei, and adhering together in the direction of their 
short diameters. On the surface towards the capsule, on the 
other hand, this substance is composed of irregular cells 
united into a network {^fiff. 7), and very similar to those 
which have been described in the Skate. The structure of 
this substance, and its relation to the basement membrane of 
the pulp, and of the capsule, clearly indicate that it is 
nothing more than the altered epithelium of these organs.* 
It is the so-called " enamel 07'r/an " of authors, and very wonder- 
ful figures and descriptions indeed have been given of it in 
various works upon the teeth. The only detailed,! and at the 
same time, as it seems to me, completely accurate account I 
have met with of this so-called enamel organ, is the very 
clear and admirable description by Mr. Nasmyth, contained 
in his posthumous work, '■Researches on the Development, 
Structure, and Di'^easea of the Teeth,^ 1849. The merits of 
this gentleman have m^t with such scant justice that I can- 
not do better than let them speak for tliemselves in this 
place ; those who work over the subject hereafter will not 
lail, 1 think, to acknowledge them as I have done. 



injected intestinal nrmcous membrane." See also p. 25 of the same ad- 
mirable essay. 

* Cioodsir (' Edin. Med. and Phys. Jonrnal,' 1839) and Todd and 
I'owraan (' Physiological Anatomj' ') state very distinctly that the pnlp 
is an ordinary |:a])illa, and the capsule an involution of the mucous mem- 
brane, and the latter justly described the membrana prefonnativa of 
the jiulp as a basement membrane (p. 17")), but they consider the 
" stellate tissue " and the enamel organ to be the " wall of the sac itself." 
KoUiker (' Mikr. Anat.,' p. 101) expresses the same opinion. 

t Mr. Tomes (' Lectures,' &'c., 1848) appears to me to have described 
the enamel organ very accurately, but he has, I tliinlv, failed to distinguish 
the ])ropcr enamel organ or ci)itlielium of the sac from the submucous 
cellular tissue — the latter is his " reiicular stage of the enamel jmlp," the 
former his " second stage " or "stellate tissue," while what lie calls tlie 
" transition part," p. 99, is, I think, the dense su]jerficial layer of tlie 
capsule, very well described by Mr. Kasmyth (vide infra) as " the inter- 
nal lamina of the dental capsule." 

Pnifessur Kiilliker (' Mikr. Anat.,' p. 9!t U) ap[ears to me to have 
fallen into the same error. 



154 HUXLEY ON THE DEVELOPMENT OF THE TEETH. 

Development of the Formative Organs of the Teeth, Follicular stage. — 
" At an early period of the follicular stage when the apex of the papilla 
rises above the level of the surrounding fence of mucous membrane, a 
small quantity of whitish matter may be detected in the groove between 
the papilla and the follicle — this is the enamel organ. Kot unfrequently 
the whitish matter has the appearance of granules which seem to have 
been separated from the surface of the follicle. These granular masses 
have a pearl white aspect, and are soft and friable. Under the micro- 
scope they are seen to be composed of cells which separate from one 
another upon the slightest compression. The cells offer considerable 
variety in respect of size and shape, some being small and round, others 
large and flattened, and furnished at one extremity with a delicate 
prolongation ; while others again are elongated and narrow, and have a 
defined and regular margin. They contain nuclei and nucleoli, and are 
covered on their interior by minute granules, which are also found in con- 
siderable abundance in their interstices." — p. 104. 

" In the numerous examinations which I have made of the stages of 
growth of the teeth here described, the enamel organs did not appear to 
me to be attached either to tlie papilla or to the surface of the follicle. 
This may probably arise from the circmnstance that all the embryos 
which I dissected had been kept for some time in diluted spirits of wine." 
—p. 105. 

He then quotes Raschkow's account of the structure in the 
Lamb and Calf, and goes on to say, — 

" In my own investigations made with the aid of one of the best micro- 
scopes of modern construction, and "with a magnifying jjower of one-tenth 
of an inch focal distance, I found the enamel substance to be composed of 
cells of three different kinds. 

" The first kind of cells are found in the, interior of the organ, and 
compose its loose, soft, and easily compressible texture. They are 
flattened and triangular in form, and connected to adjacent cells by means 
of delicate filaments prolonged from one of their angles. These appendages 
have no analogy with the filaments of areolo-fibrous tissue, as declared 
by Piaschkow. I have seen them in connexion with the cells of other 
tissues, and the error on the part of this observer must have arisen from 
the use of low microscopic powers. 

" The second kind of cells are oval in shape, and form an envelope to 
the preceding : they are situated both upon the superficial and deep aspect 
of the latter. 

" The third kind of cells occupy the deep stratum of the enamel organ, 
lying in contact with the dental jiapilla. They are narrow and oblong in 
8hai)e, and are an-anged closely side by side ; one of their extremities 
being in relation with the papilla, the other being directed outwards. 
They are firmly connected together, and have a radiated position in 
rcsject of the papilla. It is to the layer formed by these cells that 
Ha.schkow has assigned the name of enamel membrane. Taking this view 
of the construction of the enamel organ, I cannot perceive any grounds for 
the division of it into two parts suggested by the descrij)tion of Raschkow, 
It is ol)viously notliing more than a single organ, and the difference in 
the form and arrangement of the cells must simply be regarded as a tran- 
sition of the first and second kinds into those of the third— the latter 
being in tiie state of preparation for the rece])tion of the calcareous salts. 

" 'i'ho mucous nienil)rane which rises in tlie form of a ring fence around 
the i)apilla develr.ped from the dental groove is the future dnital capsule. 
At an early period it is difiicuit to determine to what extent the internal 



HUXLEY ON THE DEVELOPMENT OF THE TEETH. 155 

surface of the growing follicle differs from mucous membrane. That it 
does so may be inferred from the change in function which it assumes ; 
and at a later j^eriod, when the follicle is about to close, the difference in 
. its organic character becomes strikingly obvious. For example, it is 
white, silvery, loose, and rugous, and easily falls into folds, and, under 
the microscope, offers the appearance of a number of minute cells possess- 
ing characters widelj' different from those of the epitlielium. 

" A portion of the internal lamina of the dental capsule, placed imder 
the microscope, shows it to be composed of laj'ers of cells loosely arranged, 
and separated bj- interspaces equal to half the diameter of the cell. The 
cells are oval in shape, and provided Avith one or more distinct nuclei, and 
they contain in their interior a small quantity of granular matter. The 
internal lamina of the dental capsule maintains but a slight degree of 
adhesion with the enamel organ, and possesses no vessels. Subjacent to it 
is a network of blood-vessels, supported by a web of areolo-fibrous tissue 
formed by the interlacement of tine homogeneous filaments, among which 
nucleated cells are not unfrequently observed." — p. 107. 

Saccular Stages. — When the sac closes — ■ 

" The space between the pulp and the sac becomes filled with a fluid 
secretion which distends its cavity, and often produces a conspicuous 
enlargement in the situation of the tooth." — p. 108. 

" On the part of the capsule corresponding with the sides and neck of 
the crown is a flat portion of the enamel organ, which is destined to the 
formation of the enamel in that situation. This lamina has a well defined 
inferior border at a later period in the growth of the enamel organ ; the 
appearance which it presented of a gelatinous mass is lost, and the 
substance contracts into a membranous layer. At this time also the 
prominences from the internal surface of the capsule have enlarged, and 
have become vascular and more closely adherent to the enamel organ. 
Some writers have inferred from this appearance that the enamel organ 
itself becomes vascular,* but this is not the fact ; it is simply that portion 
of the capsule which lies in contact with the enamel organ that presents 
the vascularity referred to. 

" The dental capsule being originally, as we have seen, a production of 
the mucous membrane of the alveolar groove, is attached by its external 
surface to the neighbouring soft parts by means of loose areolo-fibrous 
tissue. Blood-vessels ramify very freely in this tunic, and from the 
interlacement which they then form, numerous capillary loops are given 
off, which extend into the superficial portion of the membrane. These 
vascular loops are separated from the enamel organ by a delicate layer of 
cells, the characters of which have been already explained. 

" Not the least interesting of the features attendant upon the develop- 
ment of the teeth is the relation which the capsule bears to the piUp and 
to the tooth at various periods of its growth. In the follicular and early 
periods of the saccular stage, previously to the commencement of the 
formation of the ivory, the capsule is continuous with the base of the 
dental papilla ;f and at a subsequent period, when the ivory of the crown 

* Kaschkow, in a note appended to his Eesearches, remarks that he has 
observed the enamel organ to receive blood-vessels in certain parts, and 
believes the parenchyma of the organ to be pervaded by capillary vessels. 
The conclusion which he deduces from this observation is, that the enamel 
organ was from the beginning joined to the capsule. 

t It passes upwards over it, forming a distinct envelope, separated from 
the layer of mucous membrane externally. 



15(3 HUXLEY ON THE DEVELOPMENT OF THE TEETH. 

forms a complete covering to the pulj^, the same arrangemeut takes place. 
But at a more advanced stage in the growth of the tooth, when its forma- 
tion has proceeded bej'ond the limit of the crown, the capside attaches 
itself closely around the neck, and the connexion of the two structures is 
so firm, that every attempt to effect their separation generally results in 
the laceration of the membrane. The continued growth of the tooth 
carries the capsule upwards with the rising alveolus to the under part of 
the gum, which now stretches over it ; when pressed upon by the surface 
of the crown, it becomes atrophied and absorbed. No portion of the 
capsule seems to pass down into the alveolus." — p. 110. 

Everything that I have seen confirms this admirable de- 
scription as to matters of fact, and the only objections I shall 
have to offer are to certain of Mr. Nasmyth's conclusions. 

In Man, then, as in the Skate, the Mackerel, and the Frog, 
the tooth-pulp is a dermic process bounded by its basement 
membrane ; the capsule is an involution of the derm, bounded 
by its basement membrane ; and the epithelium of these 
organs lies between them, having in this case received the 
name of " Enamel-organ,'" from the supposition that the enamel 
was developed by the calcification of its elements. Of this, 
however, I shall speak below. 

There is an important difference between the dental sac of 
the Calf and that of Man, which has given rise to much con- 
fusion. 

The " actinenchymatous " tissue (Raschkow) of the former 
does not at all correspond with the stellate tissue of the latter, 
as has been assumed by all writers. In fact, in the Calf the 
wall ot the capsule is separated by only a very narrow space 
Irom the surface of the pulp, and this space is completely 
filled up by elongated cylindrical epitlielium cells, which glue 
the capsule to the pulp. Between the basement membrane of 
the capsule and the alveolar wall, indeed, there is a very wide 
interval (see Owen, /. c, pi. CXXII. a, fig. 9 e) occupied by 
Kaschkow's actlnenchyma. This, however, is nothing more 
than tho loose submucous cellular tissue of the gum, similar 
to that so well described by Mr. Nasmyth in the wall of the 
capsule of man. Professor Owen says {I. c, Introduction, 
p. lix.) that " no ca])illaries pass from the capsule into the 
actinenchymatous pulp of the enamel." But those which 1 
have exam i nod do not bear out this statement ; in fact, this 
lissuc presents one of the most beautiful and obvious vascular 
networks with which I am acquainted,* 

The true liomologue of the " enamel organ " in Man there- 
fore, in the Calf, is not the actinenchymatous tissue, but the thin 

* BlaUe, wlio wrote in 1801, mentions the vascularity of the " spongy " 
outer uieiiibrane of the tooth sac in the calf; he says it is "very 
vascular." — p. Hi. . j 



HUXLEY ON THE DEVELOPMENT OF THE TEETH. 157 

layer of epithelium between this and the pulp. The general 
relations of the different dental organs are, in other respects, 
the same in the Calf as in Alan. 

I may now proceed to the second question. f^Fhat is the 
relation of the proper dental tissues to the three orrjans of the 
tooth capsule ? 

The answer is shortly this. Neither the capsule nor the 
" Enamel-organ " take any direct share in the development 
of the dental tissues, all three of which — viz. enamel, dentine, 
and cement — are formed beneath the membrana prefer mativa, 
or basement membrane of the pulp. In proof of this asser- 
tion, I have to offer the following facts : — If, in a human 
foetus of the seventh month, a dental capsule (sav of an in- 
cisor) be treated as I have above described, it will generally 
happen that the surface of the young tooth-cap appears quite 
smooth under a low power ; or it may be that a few of the 
elongated cells of the " organon adamantince " adheres to it. 
In any case the adhesion is loose, and these cells may be 
readily detached. Under a higher power the surface of the 
upper part of the ossified cap appears reticulated, the meshes 
being about l-5000th of an inch in diameter. At the lower 
part, where only a thia layer of dentine is formed, this ap- 
pearance is less distinct, but the surface is somewhat wrinkled, 
the wrinkles sometimes forming large and pretty regular 
meshes. V^iewed in profile, these wrinkles are seen to be 
produced by the folding of a delicate structureless membrane, 
Avhich is continuous below with the membrana preforniativa. 
Towards the apex the tooth substance is almost too opaque 
to make much out of it : the yellowish enamel, however, can 
generally be distinguished from the dentine. 

Now, while the object is under a low power of the micro- 
scope, add some strong acetic acid ; a voluminous transparent 
membrane will immediately be raised up in large folds from 
the whole surface of the tooth. If the acetic acid be pretty 
strong, it soon softens the substance of the tooth a little, and 
then a slight pressure exhibits very distinctly the ends of the 
enamel fibres under this membrane. There can be no question 
about this fact, as I have been able to demonstrate it to the 
satisfaction of my friends, Mr. Busk and Professor Quekett. 
The membrane is about l-2500th to l-lGOOth of an inch 
thick, perfectly clear and transparent, and under a high 
power exhibits innumerable little ridges upon its outer sur- 
face, which bound spaces sometimes oval and sometimes 
(juadraugular, and about l-5(K)()th of an inch in diameter. 
Furthermore, at its lower edge this membrane gradually loses 



158 HUXLEY ON THE DEVELOPMENT OF THE TEETH. 

all structure, and passes into the membrana preformativa.''^ In 
fact, it is the altered membrana proformativa itself, no trace of 
which has ever yet been found in the locality in which, ac- 
cording to the prevalent hypotheses upon the development 
of the teeth, it should exist — viz., between the enamel and 
the dentine. 

In the Calf t a similar membrane may be demonstrated, but 
it is much more delicate, and I have not seen the peculiar 
areolae upon its surface. 

In the Frog, in which the layer of enamel is very thin and 
structureless, the membrane (fg. 8) may be very readily de- 
monstrated by the action of dilute hydrochloric acid, which in 
this animal, as in the Mackerel and Skate, dissolves out the 
enamel layer at once, while it only acts gradually upon the 
dentine. 

In all these animals I have examined the smallest teeth I 
could find perfectly entire, without any rough mechanical 
treatment, which I should think would destroy the delicate 
membrane. 

In the Frog, its surface is in parts reticulated, as in Man; 
in the Mackerel and Skate {figs. 9, 12 ) I have been 
unable to find any such reticulation. In both these the 
enamel forms a conical cap of almost structureless or ob- 
scurely fibrous substance at the extremity of the tooth, while 
the layer upon the body of the tooth is very thin.| In the 
Skate it is thick, dense, yellowish, structureless, and perfectly 
smooth ; but in the Mackerel it is developed upon the lateral 
edges of the young tooth into sharp notched processes ; lines 
stretch across the body of the tooth from these, not unlike 
the contour lines one sees on the enamel of a young human 
tooth. 

A membrane, corresponding with that which has been de- 
scribed in the human subject then, is also found in members 
of each of the other groups of Vertebrata which possess teeth. 
In the human sul)jcct, and in Mammals, this membrane was 

* It is stated, 1»3' all the writers on the subject whom I have consulted, 
that the niemVirana prel'ormativa is the tirst portion of the tooth wliich 
ossilies. This statement, however, is never supported by evidence ; and 
my own observations lead to precisely the reverse conclusions. 

t »S'fc Ilassall, Micr. Anatomy, p. 318. 

X As this " dense exterior layer " may be dissolved out by dilute acid, 
leaving the " membrana propria of the pulp," which is very much thinner, 
standin;^', it is (piito clear that it is not " formed by the calcification of 
the meml)rana jiropria of the ]iulp, which thcrel'ure precedes the formation 
of ordinary dintine." — {(Jdnutiifintpliy, p. 17). Why should it not be 
callc<l enamel ? It has at least as much claim to this title as that of the 
l''rog. 



HUXLEY ON THE DEVELOPMENT OF THE TEETH. 159 

discovered, and very accurately figured and described, four- 
teen years ago (that is, in January, 1839, in the ' Medico- 
Chirurgical Transactions), by Mr. Nasmyth, under the name 
of the " persistent capsular investment." No cjuestion has 
ever been raised as to the right of Mr, Nasmyth to this dis- 
covery ; but it is remarkable, that neither in Professor Owen's 
' Odontography,' which is the first subsequent work upon the 
teeth, nor in Professor KoUiker's ' Mikroskopische Anatomie,' 
which is the last, is there any notice of Mr. Nasmyth's dis- 
covery. Kolliker, indeed (/. c, pp. 76, 77), describes the 
structure as " schmelz-oberhautchen," but his description 
is not so good as that of Nasmyth, and he states that it does 
not extend over the cement — Nasmyth having shown that it 
does. Unfortunately, however, the latter, like all who have 
succeeded him, misled by the supposed mode of development 
of the enamel from the enamel-organ, imagined that, as the 
" persistent capsule " was outside the enamel it could be 
nothing else than the membrane of the dental capsule ; and 
hence the erroneous description of the adherence of the latter 
to the crown of the tooth, which 1 have already quoted. Had 
he chanced to examine a tooth before its eruption, he would 
at once have seen the incorrectness of his hypothesis. 

Since then this " Nasmyth's membrane " is identical, on 
the one hand, with the persistent capsule which lies external 
to both enamel and cement, and, upon the other hand, with 
the preformative membrane of Raschkow, or otherwise with 
the basement membrane of the pulp ; it is clear that all the 
tissues of the tooth are formed beneath the basement membrane 
of the indp ; in other words, they are all true dermic struc- 
tures — none epidermic* 



The third problem was, the relation of the histological ele- 
ments of the soft parts (that is, as we now see, of the pulp) 
to the Dentine, Enamel, and Cement. 

Three theories have been prevalent as to the mode of de- 
velopment of the dentine. Tlie first, the old excretion theory^ 
need not be considered here, as it has been given up on all 
sides. The second, the Conversion theory, consists essentially 

* That the enamel is not formed directlj^ from the enamel pnlp might 
have been conchided from Professor Cioodsir's observations Q. c, p. 25). 
He says, " The absorption (in the granular matter) goes on increasing as 
the tooth substance is deposited, and when the latter reaches the base of 
the piilp, the former disappears, and the interior of the dental sac assumes 
the villous vascular appearance of a mucous membrane. 'I'liis change is 
nearly completed about tlie seventh or eighth month." It will not be 
said, however, that the growth of the enamel ceases at the seventh or 
eighth month. 



160 HUXLEY ON THE DEVELOPMENT OF THE TEETH. 

in the supposition that the dentine is the "ossified pulp;" 
that the histological elements of the pulp become calcified 
and converted clirectlv into the dentine — the arrangement of 
the elements of the dentine depending upon tbat of the 
elements of the pulp. This is the doctrine maintained by 
Blake, Schwann, Nasmyth, Owen, Tomes, Henle, Todd and 
Bowman, and, more or less doubtfully, by Kolliker and 
Hildebrandt.* The third theory is that contained in the 
remarkable phrase of Raschkow. 

" Postquam . . . fibrarura dentalium stratum depositnm est (quoted by 
Schwann) idem processus continuo ab externa regione internam versus 
progreditur gtrminis dentalis partnchymute materiam Rupj)editante . . . . 
Conversaj fibi-arum dentaUum flexuraj qu<T, juxta latitudinis dimensionem 
crescunt, dum ab externa regione internam versus procedunt sibi invicem 
appooitaj continues canaliculos effinguut, qui ad substantia? dentalis 
peripheriam exorsi multis parvis anfractibus ad ]iul]">am dentalem cavum- 
(|ue ipsius tendunt, ibique aperti finiuntur novis ibi quamdiu substantias 
dentalis formatio durat fibris dentalibus aggregandis inservientes." 

The dentinal substance, that is, is deposited within the 
pulp beneath the membrana preformativa in definite masses 
^ Raschkow calls them fibres, to which, indeed, under a low 
power tliey have a remarkable resemblance), the gaps between 
which eventually constitute the dentinal tubules. This, if a 
name be wanted, might be called the Deposition Theory, and 
is especially characterized by its asserting that the histological 
elements of the pulp do not enter as such into the dentine. 
The following description of the young dentine in the human 
subject holds good for all the animals which I have examined ; 
and if it be true, I think the incorrectness of the Conversion 
Theory necessarilv follows. 

To justify my own method of procedure, however, I am 
necessitated to remark that I have been unable to verify the 
statement of Professor Owen (/. c, Introduction, p. xxxix.), that 
the teeth of Man " will not yield a view of the cap of new- 
formed ivory and the subjacent pulp in undisturbed con- 
nexion by transmitted light with the requisite magnifying 
power." On the contrary, I have found it sufficiently easy, 
l)y cutting off the half-ossified cusp of a young molar, or 
even by sul)mitting an entire canine or incisor to slight pres- 
sure, to obtain a most distinct view of the pulp in undisturbed 
connexion with the dentine, and in a profile view. Indeed, 

* Dr. Sliarjjcy, on the other baud, with characteristic caution, after 
citing tlic statements of some of the advocates of tlie Conversion Theory, 
adds, " We nuist confess tliat, after a careful examination of the hiunan 
te<!t,h, we liavebeen unable to discover any of the above-mentioned changes, 
except I lie ciilargomeiit of the more superficial cells of tbe pulp, and their 
elongations in the iinmetliate viciuitv of the dentine."— Quain and Sharpey, 
p. 'J^H. 



HUXLEY ON THE DEVELOPMENT OF THE TEETH. KU 

had other observers adopted this method, I do not think they 
would have been led to consider the lacunae in ^oung den- 
tine, whose true nature was demonstrated by Raschkow, as 
metamorphosed nuclei of the pulp. 

When the ossifying boundary of a tooth-pulp is examined 
in the way which I have here pointed out, it is seen that where 
dentification has not begun, the membrana preformativa is in 
immediate contact with the substance of the pulp, composed 
of a homogeneous transparent base, in which closely-arranged 
" nuclei " are embedded. These are rounded or polygonal, 
apjiarently vascular ; contain one or more granules, and are 
about l-2500th — l-3500th of an inch in diameter. Passing 
towards the ossifying edge, we see in the profile view a clear, 
more strongly refracting layer, giadually increasing in thick- 
ness, which begins to separate the proper substance of the pulp 
from the membrana preformativa. This is at first quite struc- 
tureless to all appearance, both in this view and in one per- 
pendicular to its surface. When it has attained a thickness of 
l-2500th of an inch, however, it acquires a sort of mottled 
appearance in the profile view, while superficially numerous 
very minute irregular cavities, about l-5000th of an inch apart, 
present themselves (fig. 5), In a thick portion of the den- 
tine (3-5000ths) these cavities are very readily seen in the 
profile view to be elongated into canals ; superficially they 
are rather larger ; and as they run somewhat obliquely, it may 
very readily happen that, unless the focusing of the micro- 
scope be very careful, one will run into the other, and so 
produce the appearance of fibres described by Raschkow. 

This young dentine is as transparent as glass. No trace 
of " nuclei " can at any time be discovered in it ; the bodies 
which have been described as such being, as I have said, 
simjjly lacunce ; nor, if strong acids be used so as to dissolve 
out the calcareous matter, are anv nuclei brought to light, 
though those which exist in the pulp became much more dis- 
tinct, and even coarse, in their outlines. Again, if to a pulp 
thus treated, a weak solution of iodine be added, the nitro- 
genous substance of the pulp is immediately coloured deep 
yellow, the nuclei themselves becoming brown ; but the den- 
tine remains pale, except that here and there a yellow prt)- 
cess of the matrix of the pulp may be seen stretching a little 
way into one of the canals of the dentine. I have only ob- 
served this, however, once. I believe tliat these facts afford 
sufficient demonstration that the pulp is not converted directly 
into the dentine, and that, the structure of the latter does not 
depend upon the calcification of pre-existing elements. 

1 am the more satisfied with this negative evidence, as in 



162 HUXLEY OX THE DEVELOPMENT OF THE TEETH. 

young bone it is easy to demonstrate the " nuclei " in the 
lacunae bv the aid of acids, Sec 

As to whether the perpendicularly crowded " nuclei " of 
the pulp under the dentine disappear, or whetlier they are 
merely pressed inwards, I cannot pretend to offer a decisive 
opinion. The former supposition, however, if we may judge 
by the analogy of bone, appears more probable. Dentine, 
in fact, might be considered as a kind of bone, in which the 
lacunae are not formed in consequence of the early disap- 
pearance of the nuclei, whose persistence for a longer or 
shorter period appears to be the sole cause of their existence 
in bone.* 

Still less can the enamel be produced by any conversion of 
a cellular structure. Between it and anything which can be 
called a nucleated cell it has on the outer side A'asmyth's 
membrane ; on the inner, the layer of dentine, which in Man 
is formed before it. The fibres of which it is composed are 
structureless, and almost horny ; and I think we must be content 
for the present to consider its existence and its structure as 
ultimate facts, not explicable by the Cell Theory. It is par- 
ticularly worthy of notice that in the Skate the dermal teeth or 
plates on the upper surface of the head have as distinct a layer 
of enamel as those of the mouth, though in this case there is 
most assuredly neither rudimentary capsule nor " enamel 
organ." 

In a morphological point of view, the relations of the cement 
show it to be homologous with the enamel. In a very beau- 
tiful section of a human tooth from Mr. Busk's cabinet, the 
upper portion of the cement exhibits in places a very distinct 
transverse striation, resembling its perfect enamel. But the 
transition of the one structure into the other is best exliibited 
in tlie young Calf by the cement of the fang of a molar which 
had not cut the gum. Here it is a white substance, from 
which generally a fitting section can be cut only with some 
difficulty, in consequence of its friability. The layer is about 
l-40th of an inch thick, and consists of an external delicate 
structureless Nasmytli's membrane; internal to which three- 

* I have here no space to enter into the discussion of the various 
hypotheses and assertions, respecting the development of the dentine, 
made by tlie various authors whose names I have cited. I trust it will 
not on that account be supposed that 1 have necrlected to make myself 
acquainted witli thom. But there are two statements to which I must 
refer in conlirmation of my own view. The one is that by Dr. Sharpey 
already quoted : the other is the very just declaration (in italics) by Pro- 
fessor Kollikcr (Uaudbuch, p. 386), that " the most curefid invest u/oticm 
e.rhil)it» no trace of amj elongation of nuclei'" in the peripheral cells of 
he pulp. 



HUXLEY ON THE DEVELOPMENT OF THE TEETH. 1(33 

fourths of the thickness of the layer are formed by parallel 
fibres l-5000th of an inch in diameter, quite structureless, 
and completely resembling- enamel fibres, but absolutely 
enormous (as much as l-60th of an inch) in length. These 
fibres wei-e softened and rendered pale by the action of caustic 
ammonia. The inner fourth of the layer of cement was com- 
posed of an inextricably interlaced body of such fibres, 
united into a mass, which in some places was almost homo- 
geneous, by calcareous salts, and containing here and there 
lacunae 1-1 600th of an inch in length, similar to those of 
bone. That this structure was the young cement is certain, 
inasmuch as no enamel is formed on the fang of the tooth, to 
say nothing of the presence of the lacuna^. On the root of 
the fang of the molar in fi'ont of this, which had cut the gum 
some time, and had come into use, the cement had the ordi- 
nary structure. It may be worth while to add that in these 
teeth the capsule, though closely connected with the outer 
surface of the fang, could be readily stripped from it, and 
then exhibited a layer of epithelium upon its inner surface, 
showing clearly that the cement was not derived from its 
ossification. 

It may be concluded, then, — 

1. The teeth are true dermic structures, formed by the de- 
posit of calcareous matter beneath the basement membrane of 
a dermic papilla, or tliat which corresponds with one. 

2. Neither the capsule nor the " enamel-organ," which 
consists of the epithelium of both the papilla and the capsule, 
contribute directly in any way to the development of the dental 
tissues, though they may indirectly. 

3. The histological elements of the pulp take no direct 
part (except, perhaps, eventually in the cement) in the deve- 
lopment of the dental tissues, becoming either absorbed or 
being pressed in by the gradual increase of the latter. The 
Conversion Theory is, therefore, as incorrect as the Excretion 
Theory, and the dentine is formed, not by ossification of the 
histological elements of the pulp, but by deposition in it, 
" parenchymate materiam suppeditante." 

I have already exceeded my limits, and I must, therefore, 
dismiss my last point very concisely. The true homologucs 
of the teeth in Man are, I think, tlie Hairs. As Hildebrandt 
says, " As the Hairs in their bulb (sac), so the Teeth are de- 
veloped in their capsules." The stage of the free papilla, 
which does not occur in the hairs of man, is absent in the 
teeth of the Mackarel and Frog, and, indeed, it would seem 
in the permanent dental capsules of man also. 

Substitute corneous matter for calcareous, and tlu> Tooth 



1(54 HUXLEY ON THE DEVELOPMENT OF THE TEETH. 

would be a Hair. The cortical sul)stance of the hair contains 
canals not unlike those of the dentine ; its relation to a 
dermal papilla is the same as that of the dentine:* for 
although it is universally stated to be such, I think it can be 
shown^that the hair shaft is not an epidermic structure, but a 
dermic one. 

Again, the so-called cuticle of the hair corresponds in all 
respects, except absolute and relative size, with the enamel 
— its inner layer with the enamel proper — its outer with Nas- 
mvth's membrane. On the root of the hair the cuticle 
is not continuous with the proper epidermic cells, but with 
a structureless membrane, which occupies more or less dis- 
tinctly the place of a viemhrana preformativa. The two root- 
sheaths, again — true epidermic structures, but which do not 
enter all into the construction of the hair proper — represent 
the altered and unaltered portions of the '■'■ enamel-organ T 

Hairs and Teeth, then, are organs in all respects homolo- 
gous, and true dermal organs. Under the same category, 
probably, will come Feathers and the Scales of fishes. 

The Nails, on the other band, seem to be purely epidermic, 
at least according to Kolliker's account of their development 
(/. c, p. 119) ; and in that case they are the homologues of the 
root-sheaths and enamel-organs of Hairs and Teeth. 

* See Todd and Bo\\Tiian, p. 175. 



( 165 ) 

On the Photographic Delineation of Microscojnc Objects by 
Artificial Illumination. By George Shadbolt, Esq. 

The application of Photography to the purpose of delineat- 
ing microscopic forms I have for some years entertained as 
a favourite project ; but some practical difficulties of mani- 
lation deterred me from putting it to the test until quite 
recently, when a sufficient stimulus was applied in the beau- 
tiful specimens both on paper and glass exhibited in the 
month of October last, at the Microscopical Society of London, 
by Mr. Joseph Delves, of Tonbridge Wells. Of the excellent 
promise for a highly valuable adjunct to microscopic science, 
the proofs in the present Number of the Journal will afford 
your readers an opportunity of judging. 

As it is not my intention to enter into particulars of the 
rise and progress of this art as connected with the microscope, 
I will only observe that the earliest microscopic photographs 
which I had the pleasure of seeing were some Daguerreotypes 
executed by Mr. Richard Hodgson by the aid of the direct rays 
of the sun ; and for these I believe he is entitled to claim the 
honour of having been the first to produce a picture of this 
kind. 

But however beautiful the sharpness and detail of pictures 
upon metallic plates, there are many causes to confine the 
practice of the Daguerreotypic art within such very contracted 
limits as to render it of but little use to the microscopist ; 
whereas the increasing beauty and sensibility of the Collodion 
process renders it a much more encouraging medium for fur- 
ther experiment in this direction, besides offering the addi- 
tional inducement of enabling one to transmit duplicates upon 
paper to others engaged upon similar observations at a distant 
part, by which comparisons of much value can be made, and 
without the expense and inconvenience of having to execute 
duplicates from the objects themselves. 

As it happens that the great majority of the followers of 
microscopic science are mostly engaged in professional or 
other business pursuits during the day-time, and in most 
instances at a distance from home, it occurred to me that if 
artificial light could be made to act sufficiently energetically 
to produce microscopic pictures, it would be a very consider- 
able advantage to a large number of persons who would other- 
wise not be able to avail themselves of so excellent <an assistant 
as the pliotographic art ; and further, that to render it practically 
useful, it must be done by an illumination readily accessible 
and inexpensive ; I therefore determined to institute a series of 
experiments with this end in view, and having availed myself 

VOL. 1. N 



160 ON THE PHOTOGRAPHIC DELINEATION 

of all the hints thrown out by Mr. Delves, Mr. Hogg, and 
others, at the Microscopical meeting in October, after very 
many failures and no small amount of trouble, I at length was 
fortunate enough to meet with such success as, in my opinion, 
to offer very considerable encouragement for further operations 
with a reasonable hope of a really useful result ; and at the 
meeting of the Microscopical Society in November last I had 
the pleasure of exhibiting a picture of a Fly's Proboscis, pro- 
duced by the aid of a very small camphine lamp. In the 
hope of enlisting more labourers in this field of research, I 
purpose detailing the " modus operandi " which I have found 
most successful ; trusting that, in a short time, the little seed 
thus sown may bring forth an abundant harvest. 

I would premise that I do not advocate photography in 
microscopic^ science as a rival that will supersede the draughts- 
man, except in certain cases ; and although it may in very 
many instances do so, it will most assuredly make much more 
work than it takes away from those who follow the occupation 
of a microscopic artist. 

When the object to be delineated is flat and moderately thin, 
as compared with the necessary power in use, a very excellent 
picture may be produced without any aid from the limner ; 
but where the object is not so formed — although when under 
microscopic examination the mind can readily acquire a cor- 
rect knowledge of the form by focussing up and down — it is 
evident that from the very construction of a good objective a 
picture can only be obtained in one plane at a time, and it will 
then be necessary to take several pictures in different planes, 
and call in the artist's aid to unite the productions. The 
immense amount of time and labour that can be thus saved in 
delineating subjects of an elaborate character can only be ap- 
preciated by those who have attempted the production of 
objects of this class. 

It is scarcely necessary to enter into a preliminary explana- 
tion of the photographic phenomena, as it is of very little use 
for an entire novice in the practice of this art to commence 
upon microscopic subjects; I shall, therefore, presume that I 
am addressing those who understand the general principles of 
photograpliy, and shall therefore commence with 

T/ic Arram/rmciit of the Apparatus. — Place the microscope 
with the body in a horizontal position, and screw on the 
ohjcctive to be used, and fix the object in its proper position 
on the object-plate of the stage by pressing down the sliding 
sprmg-piece. Turn the mirror aside or remove it altogether, 
and having taken out the eyepiece, insert into the body a tube 
of hiown i^apor lined with black velvet, in order to prevent the 



OF MICROSCOPIC OBJECTS. 167 

slightest reflection from the sides, which would infallibly spoil 
every picture if allowed to operate. The lens should then be 
removed from an ordinary photographic camera, and the latter 
elevated so as to bring its centre in an exact line with the axis 
of the microscope body, which must have its eyepiece-end 
inserted in the place left vacant by the removal of the camera 
lens, and that portion of the opening not filled up by the body 
may be rendered impervious to light by a piece of black cloth, 
velvet, or other similar material. 

The lighted lamp must next be brought, so that the centre 
of the flame is in the axis of the instrument, and its distance 
must depend upon the focus of the lens used to concentrate 
the light, for which purpose an ordinary convex lens of 2^ to 
3 inches diameter, with its flat side towards the lamp, is per- 
haps as useful as any, provided a second plano-convex lens of 
that focus is interposed near the object to concentrate the light 
still more strongly. It is not necessary, or even desirable, 
that an image should' be formed of the source of light, and 
consequently the spherical aberration in such an arrangement 
as recommended is not detrimental, and may he advantageous. 

The ground glass screen to receive the image being in its 
proper place in the camera, the object may be brought to a 
correct focus in the usual way with the coarse and fine adjust- 
ment, and this cannot be done too accurately ; in fact, lor 
delicate objects, a means of magnifying the image is absolutely 
requisite, and for this purpose a positive eyepiece, placed in 
contact with the ground glass, is perhaps best. 

Most achromatic objectives of the best construction are 
slightly over-corrected (as it is termed) for colour, in order to 
compensate for a small amount of under-correction in the eye- 
piece, that is to say the violet and blue rays of the spectrum 
are therefore projected beyond the red ones. 

As it is ascertained that most of the photogenic or actinic 
rays are located in the violet end of the spectrum, it follows 
that with such a lens as is used for the microscope, the chemical 
focus will be somewhat more distant from the object than the 
visual focus, and it therefore becomes necessary to make some 
allowance for this difference. 

This may be done in two ways, either by placing the sensi- 
tive plate somewhat farther off than the ground glass on which 
the image is received, or by altering the focus by the fine 
adjustment ; the latter being the plan I prefer, as I find it 
much more accurate. 

The amount of difference between the foci probably varies 
in every objective, even apparently of the same make, and 
can only be ascertained by clirect experiment, but the follow- 

N 2 



1(38 ON THE PHOTOGRAPHIC DELINEATION 

ing may be some guide to those who wish to experiment upon 
the subject. 

An inch-and-a-half objective of Smith and Beck's make 
required to be wit/idrmvn from the object after the correct 
visual focus is ascertained l-50th of an inch, or two turns of 
their fine adjustment. 

A two-thirch of an inch object glass of same make wants a 
withdrawal of i-200th of an inch, or i a turn of the fine 
adjustment, and 

A 4-lOths of an inch, about 2 divisions, or 1-lOOOth of 
an inch farther off. With the l-4th, and higher powers, 
the difference between the foci is so minute that it is practi- 
cally unimportant. Tlie above differences are those actually 
existing in my own objectives, but, as before intimated, it does 
not follow that they will be correct for others even of the 
same makers. 

Having arranged the apparatus, focussed, and made the 
requisite adjustment for chemical focus, the ground glass may 
be removed, and the sensitive plate placed in its stead. 

As in all other photographic processes, the time of exposure 
must be varied according to the power in use, the nature of 
the object to be taken, and the amount of illumination, to 
wliich must be added in the present instance the medium in 
which the object is mounted, but from 1 to 10 minutes^ exposure 
is generally requisite. An explanation of the last named 
disturbing cause may probably be found in the beautiful dis- 
covery of Professor Stokes of the property possessed by 
certain transparent media of arresting the chemical rajs. 

Any account of the preparation of the collodion, tScc. &c. 
would be more fitted for a work on photography, and would 
render the present paper much too lengthy : moreover there is 
an abundance of information on photographic manipulatory 
details readily accessible in numerous publications, such as 
Mr. Robert Hunt's Manual, Mr. Bingham's, Mr. Archer's, Mr. 
Homes, Mr. Hennah's, cScc. &c. There are, however, one or 
two points wliich it is as well to allude to. If the film of a 
collodion picture be examined by the microscope, some 
specimens will present an appearance very much resembling 
condensed cellular tissue, such as that seen in the cuticle of 
leaves, being apparently made up of flattened irregular 
hexagonal cells ; while others seem to consist of an entirely 
structureless amorphous mass ; the latter sort of collodion is 
most suitable for microscopic purposes. 

'i'he final fixation of the picture by removal of the iodide of 
silver has a singular influence upon the result according to 
the metlH.d emi)l.iyed, and advantage may be taken of this in 



OF MICROSCOPIC OBJECTS. 169 

order to improve the effect according as it is desired to pro- 
duce glass positives or negatives ; for though all collodion 
pictures partake of both characters, one of the two should 
always be predominant. 

Of course a negative is most useful, because the drawings 
can be multiplied upon paper almost ad infinitum, but for 
certain objects the amount of detail when ve?'?/ delicate is in- 
conceivably better shown upon glass than upon paper. If 
then a negative picture be desired, it is best to develope with 
the pyrogallic acid solution, and^'^- with a solution of hypo- 
sulphite of soda ; but if, on the contrary, a positive picture is 
the desideratum, the effect will be infinitely better by fixing 
with a bath of the following, viz. : — 

Cyanide of Potassium . . . • li drams. 

Water . . . . . .1 pint. 

Nitrate of Silver . . . .15 grains. 

The cyanide to be dissolved in the water, and the crystals 
of nitrate of silver added, which immediately cause a curdy 
precipitate, but this is quickly redissolved, and the whole 
becomes quite translucent. 

By this method of fixing, the tohitcs are very much purer 
and brighter than when the hyposulphite is used, but the 
pictures do not answer so well for printing from. A still 
further intensity of the whites may be produced by develojiing 
the picture with a solution of the proto-siJphate of iron, instead 
of the pyrogallic acid, and afterwards fixing with the cyanide 
solution ; there are, however, certain difficulties of manipulation 
to overcome. The solution is made as follows : — 

Proto-sulphate of Iron in Crystals . . 1 oz. 

Water . . . .by measure 10 oz. 

Sulphuric Acid . . . ,, 1 cz. 

This is best used by placing in a glass bath and totally im- 
jnersijig the plate, which should be withdrawn the moment the 
picture is perfectly developed, which will be in from 15 to 
GO seconds, and it ought to be instantly plunged into a bath 
of plain water sufficiently copious to dilute the adherent 
moisture very considerably. The object of the bath being of 
glass, is in order to see the development of the pic ture, as 
every second it remains after it is fully produced, is to the 
detriment thereof, by causing a sort of fogginess to appear all 
over it. 

When developed with the protosulphate of iron, the 
pictures may be exposed to direct day-light before the final 
fixing, without injury, in fact with positive benefit according 
to Mr. Martin. 

The causes most frequently operating to prevent the success 



170 TEETH ON THE TONGUES OF MOLLUSCA. 

of the process are, first, want of attention to the proper illumi- 
nation ; it is to this point more than any other that the utmost 
attention should be paid, and I feel confident that by well 
concerted measures to attain this requisite, we shall eventually 
be able to obtain pictures in a tithe of the time now necessary ; 
in the second place failures more often occur from over exposure 
than from being too short a time ; thirdly, want of allowance 
for difference of visual and chemical foci. 

Tn conclusion, I would observe that some experiments upon 
the different light-producing substances would in all probability 
well repay the trouble of testing their capabilities, as from 
certain hints thrown out by Professor Stokes, there appears to 
be a very considerable diflference in the amount of actinic rays 
emitted by differing combustibles, and it seems not improbable 
that a well contrived spirit lamp may be found highly advan- 
tageous to use while taking the impression, although its light- 
giving properties are so defective. I hope shortly to be able 
to resume this subject. 



On the Teeth on the Tongues of Mollusca, By J. E. Gray, 
Ph.D , F.R.S., V.P.Z.S., P.B.S., &c. 

Lister, Leeuwenhoeck, Swammerdam, Poli, Cuvier, Fleming, 
Delle Chiaje, Verany, Eydoux, Souleyet, Van Beneden, 
Oersted, and some other naturalists, have, at various and dis- 
tant periods, described and figured the teeth on the tongues of 
isolated species of Mollusca. 

Dr. Troschel, in Wiegmann's ' Archiv,' 1836, 257, t. 9 
and 10, and 1839, 177, t. 5, f. 8, describes and figures the 
teeth of some German terrestrial and aquatic Mollusca. In 
the same Journal, 1845, 197, t. 8, f. 6, the teeth of Ampul- 
laria, and in 1849, 225, t. 4, he has described and figured 
the teeth of some exotic Bulimi and Nanince. 

The Rev. Mr. Berkeley, in the Zoological Journal (iv. 
278), describes the teeth of Ctjclostoma elegans. 

Dr. Wyman, in the Boston Journal of Nat. Hist., has 
descril)od and figured those of Tehenophorus and Glandina ; 
and Mr. Tliomson, in the Annals and Magazine of Natural 
History (1851, vii. 80, t. 3), has published a very interesting 
essay on the dentition of British Pulmonifera. 

MM. (^uoy and Gaimard, in their large government work, 
figured tlic teeth of several marine genera of exotic Mollusca ; 
but, unfortunately, on verification, the figures of some of the 
genera are so incorrect as to throw doubt on the others. 



TEETH ON THE TONGUES OF MOLLUSCA. 171 

Dr. Loven, in his very excellent paper on the Mollusca of 
Scandinavia, made some important observations on the teeth 
of some marine Mollusca ; and in a special paper on the sub- 
ject (Oversigt. af Kongl. Vetensk. Akad. Forhandl., 1847, 
175) he describes and figures the teeth of the several orders, 
families, and genera of Scandinavian Mollusca. He divides 
the tongues he has seen into fourteen groups, and separates 
the genera into families and sections, characterized by the 
number, position, and forms of the teeth, virhich opened a 
new series of characters for the systematic descriptions of the 
Mollusca. 

Messrs. Alder and Hancock, in their beautiful work on 
British Nudibranchia, and Messrs. Hancock and Embleton, 
in the Philosophical Transactions for 1852, have figured the 
teeth of several British Nudibranchiate gasteropods ; and 
Dr. Troschel, in Wiegmann's ' Archiv' (1852, 152 t.), MM. 
Eydoux and Souleyet, Voy. de Bonite, M. Oersted, and myself 
in a paper in the Annals of Natural History for 1853, have 
described and figured the teeth of some genera of marine 
Mollusca which had not been before described. 

Mr. Hancock and Dr. Embleton (Phil. Trans., 1852, 211) 
have described the development, wearing, and succession of 
the teeth of the Dorides ; they observe, " the mode of growth 
of the spiny tongues of Doris is evidently quite analogous to 
the growth and advance of the teeth of the rays and sharks, 
&c., or of the hoof and nails of Mammalia." 

Dr. Troschel, in the third edition of VViegmann and Ruthe's 
' Handbuch der Zoologie,' Berlin, 1848, proposed to divide 
the Gasteropods into four orders, according to the number of 
the teeth on the lingual band, giving them the names of — 
1. Tcenioglossa ; 2. Tuxoglossa; 3. Prohoscidea; 4. Rhijndo- 
glossa. 

In some observations on this paper (Annal. and Mag. N.H., 

1852, X. 411) I proposed to use the names of these orders 
as technical terms in the description of the families, and pro- 
posed a new one, Ctenoglossa, for the numerous uniform teeth 
of the Pulmonata and other genera ; and in a paper on the 
families of Ctenobrancldate Mollusca (Anna!, and Mag. N. H., 

1853, xi. 124), where I have described some new forms of 
teeth, I have extended the number of terms so proposed. 

Believing that it will be useful to science to have a series 
of terms to indicate the chief modifications of tlicse teeth 
which have been observed, 1 have sent you the following table 
of them, illustrated with a figure of each form, and with a list 
of the families of Mollusca which they characterize : — 

I. Rhackiglossa. The lingual membrane has a single ecu- 



172 TEETH ON THE TONGUES OF MOLLUSCA. 

tral series of teeth, as in the family Glaucidcc, Loven, t. 3, 




Fig. 1.— Yetus olla. 



Fig. 2.— Cymbiola Turncri. 




Fig. 4. — Mangelia costata. 




Fig. 5. — Chrysodomus antiquus. 



Fig. 3. -Conus, sp. 



figs. 15, 16 ; DotonidcB, Phyllirrhoidce^ LimapontiadcB of Nu- 
dibranchiata ; and VolutidcE (figs. 1, 2), of Ctenobranchiata, 

II. The lingual membrane, with tivo series of elongated 
subulate teeth, one on each side of the central line. 

a. Toxoglossa ; the teeth elongate, straight, or spiral. 

1. Conidce ; teeth with a channel on the side and barbed. 
(Fig. 3.) 

2. PleurotomidcB ; teeth subulate, straight, simple. 
(Fig. 4.) 

b. Drcpanoglossa ; the teeth curved, elongate, slender, com- 
pressed, short, conical, strong. Fhilinidce, Onchidoridce. 

III. Tlie lingual membrane, with three series of teeth ; 
central teeth simple. 

A. JIa7}iir/l(issa ; the lateral teeth versatile, attached by the 
inner eml, and capal)le of being bent over on each side 
(Fig. f)); as 

Miiricidd!, liucciiiidcc, OUvidcc ; with the lateral teeth flat ; 

and 
LamcUariadiC ; with tlic lateral teeth curved 



TEETH ON THE TONGUES OF MOLLUSCA. 



173 



B. The lateral teeth bent towards the central one. Cavoli- 
nidcB, LimacinadfB, Loven, t. 3, fig. 5, 6. Amphisphi/sadce, 
Loven, t. 3, f. 20. 

c. Odontoglossa ; the lateral teeth fixed on the same plane 
as the central ; immoveable (figs. 6 and 7) ; as 

a. Fasciolariadce ; the central teeth small, few-toothed ; 
the lateral very broad, many-toothed. (Fig. 6.) 

b. TurhinellidcB ; the central teeth moderate, largely toothed ; 
the lateral moderate, few toothed. (Fig. 7.) 




Fig. 6. — Fasciolaria filamcntosa. 





Fig. 7. — Turbinella comigera. 

Fig. 8.— Lepeta cceca. 

IV. Oplatoglossa ; the lingual membrane, with six series of 
teeth, the central large, the lateral hooked, similar. (Fig. 8.) 
LepetadcB. 

V. The lingual membrane, with seven series of teeth, the 
central recurved at the top ; the inner lateral, broader, re- 
curved at the top. 




Fig. 9. — Natica pnlchella. 

a. Tcenioglossa ; the two other lateral, more or less conical, 
incurved. (Fig. 9.) 

Among Ptenobranchus Gasteropods : — Pterotrachidcc, Atlan- 
tida, Paliidinidce, Ampullar iadm. Melaniadce, Littorinidfe, 
Valvatidce, NaticidcB (fig. 9), Velutinida, Cyprceadat, Tricho- 
tropidcB, Capulidce, Cah/ptrceadcc, Pediculariad<v, Cyclosto- 
midte, Heliciaidce. Aporrhaida;, Stromhidcc, Loligidce. Sepio- 
lidce, OctopidcB. 

b. Dactyloglossa ; the two outer lateral teeth broad, divided 
into many filiform lobes at the end (fig. 10), as Amphi- 
perasidce. 



174 



TEETH ON THE TONGUES OF MOLLUSCA. 




>^^\?^ 




Fig. 10. — Amiihiperas Ovrnu. 

VI. The lingual membrane, with numerous series of teeth. 

A. Ctenofjlossa. The teeth nearly uniform, similar; the 
central distinct or wanting. 

Among the Pulmobranchiata, as Veronicellidce, Arionidce, 
Helicida', Aziriculadce, Lymneadce. Amphiholidce, Siphona- 
riadce, CydostomidcB (?), HelicinadcB, Onchidiada {Peronid). 

Ptenobranchiata, as JanthinadcB, Scalariadce (fig. 11), Cas- 
sididce. 

Pleurobranchiata, as BulladcB^ Aplydadce, Amplustridte, 
ActeonidcB. 

Nudibranchiata, as Tritoniad(B, Doridce, Dipliyllidiadcp, 

Pteropoda, as Clionidce. 




Fig. U.— Scalaria Turtonl. 

B. Ilcteronlossa central (rarely wanting) ; and inner lateral 
teeth larger, often unequal, and variously shaped ; the 
lateral few, uniform. (Fig. 12.) 
Amongst the Nudibranchiata, as Triopidcc {Triopa^ and 
Idalid). Loven, t. 3, figs. 9, 10, 11. 

Pleurobranchiata, as Cylichna in Bullida. Loven, t. 3, 
fig. 21. 

Scutibranchiata, as Dentaliada, Chitonidce (fig. 12); Patel- 
lidie (fig. 13) ; Tecturidce (fig. 14). 




Fig. 12.-01111011 ciiicreus. 



TEETH ON THE TONGUES OF MOLLUSCA. 



175 




Fig. 14.— Tectxira testudiiialis 



Fig. 13. — Patella ^Tilgata. 



c. Rhijpidoglossa. The central and inner lateral teeth 

larger, often unequal and variously formed ; the lateral 

teeth uniform, very numerous (fig. 15). 

Turbiiddce, Liotiadce, Trochidce, Stomatellid(Py Haliotida;^ 

FissurellidcB . NeritidcE, all belonging to the first division of 

Scutibranchiata. 




/ 



Fig. 15. — Emarginula crassa. 



I may observe, that, from the examination I have been able 
to make of numerous kinds of Molluscs, the teeth offer 
one of the best characters for their division into natural 
families. I have such confidence in their permanence and 
importance in the economy of the animals, that, if I found any 
very considerable modification in the teeth of two genera 
which had been referred to the same family, or, much more, 
of two species, which had been referred to the same genus, 
I should conclude that they had been erroneously placed in 
such close proximity — as this modification must indicate an 
important difference in the habits and manners of the living 
species under consideration, which had before escaped our 
observation. 

The researches of Dr. Loven, who has figured and described 
the teeth of several Scandinavian species of Nassa, Chrt/so- 
domus, Buccinum, Sfc. ; of Mr. Thomson, who has described 



176 COLOURLESS CORPUSCLES OF THE BLOOD. 

the teeth of the various species of British Helices, Lijmnea, 
&c. Mr. Alder and Mr. Hancock's researches on the teeth of 
Nudibranchiata, and my own observation of the teeth of seve- 
ral extra European species of Tritons, Murices, Fasciolarics , 
6:c., show that they offer such modifications in the form, 
surface, and shape of the edges of the individual teeth as to 
afford very good characters for the distinction of the species. 

They will, therefore, most probably furnish most important 
characters for the distinction of the species, especially of such 
genera as Crepidida, Calyjitrcea, Patella, &c., which, from their 
being long attached to particular places, change the external 
character of their shells, and thence assume particular forms, 
which have been regarded as distinct species. 

I may add, that the lingual band bearing the teeth, or, as it 
is termed, the " tongue" of the Mollusca, makes a most in- 
teresting object for the microscope ; and I hope that persons 
living in different parts of the globe will make a collection of 
the tongues of the marine, terrestrial, and fluviatile Mollusca 
in their neighbourhood, carefully marking the name of the 
species to which they belong, as by so doing they will afford 
a most important addition to the knowledge of Malacology. 



Excess of the Colourless Corpuscles of the Blood {Leucocyt hernia) 
occurring in Cases of Goitre. By Thomas S. Holland, 
M.D., Corresponding Member of the Societe Anatoraique 
and of the Parisian I^Iedical Society, Cork. 

The impulse which the researches of Professors Bennett and 
Virchow have given to the study of the histological alterations 
in the Blood will be, I presume, sufficient excuse for the 
publication of these observations ; and by confining myself to 
a simple narration of facts I hope to secure the attention of 
those who live in districts in which Goitre is of frequent 
occurrence, and perhaps induce them to make, in all such 
cases, a microscopical examination of the blood. 

Case 1st.* — Johannah Nissl, aged 70, died in the Allge- 
incine Krankenhaus of Vienna on the 17th of September, 
1851 ; and dissection made, twenty-eight hours after death, 
exhil)it(;d the following aj)poarances. 

Body of the middle height, thin, pale ; lower extremities 

♦ I ain imlobtoil to the kindiics-s of rrofcssor Rokitansky for permission 
to pul.lisli flicKc (;a.scs, and the preparation, from case No. 1, is iu the 
I'atholoLfieal Museum. 



COLOURLESS CORPUSCLES OF THE BLOOD. 177 

ccdematous, pupils dilated, neck thick, thorax small, sternum 
prominent, mammae atrophied. 

Head and Neck. — Calvarium porous ; a small amount of 
coagulated blood in the superior longitudinal sinus ; pia mater 
pale, opaque, and cedematous ; brain soft, with a half ounce 
of serum in the ventricles, and small serous cysts on the 
choroid plexus. 

Neck and Thorax. — ThjToid gland so much enlarged that 
its right half had acquired the size of a man's fist, and the 
isthmus that of an eg^, while a process extending from the 
latter lay upon the membrana obturatoria. The left half of 
the gland reached as low as the right ventricle, extending 
slightly across the chest at the superior opening of the thorax, 
and measuring three inches in length by one in thickness. 
The entire mass was made up of small lobules, having the 
normal structure of the gland, through which passed large 
and somewhat congested veins containing fluid blood. In 
each pleural cavity about two pints of brownish serous fluid, 
which had compressed the inferior lobes of both lungs, and 
there was much mucus in the bronchi on each side. Two or 
three ounces of serous fluid in the pericardium ; general dila- 
tation of the heart's cavities, more especially the right 
ventricle, and its base lay a little lower than usual. Pul- 
monary artery dilated to half again its normal size, while the 
heart's cavities contained much fluid, or but imperfectly coa- 
gulated blood ; valves healthy. 

Abdomen. — Right lobe of the liver somewhat enlarged, and 
presenting the so-called nutmeg appearance ; in the gall 
bladder a few drops of yellowish thin gall, its mucous mem- 
brane being thickened and cedematous. Spleen normal in 
size, colour, and consistence. Kidneys rather large, and the 
cortical substance of a yellowish brown colour. Cavity of 
the uterus exceedingly small, with the Internal orifice of the 
cervix closed. 

Microscopical Examination. — The spleen was most carefully 
examined, and appeared perfectly free from all trace of 
diseased action. The fluid and partly coagulated blood taken 
from the left ventricle exhibited a fine demonstration of that 
state to which Professor Virchow gives the name of Leu- 
koemie,* and Dr. Bennettf that of Leucocythemia, the colour- 
less corpuscles being about seven or eight times more 
numerous than they appear ordinarily in healthy blood, and 



* Archiv fiir pathologischc Anatomic unci Physiologic. 1852. vol. V. 
p. 43. 

t On Leucocythemia, or White Cell Blood. Eelinburgli. 1852. 



178 PRACTICAL APPLICATION OF PHOTOGRAPHY. 

I had an opportunity of having this observation confirmed by 
my friend Dr, Robert MacDonnell of Dublin, who was at 
that time in Vienna. 

Case 2nd. — I regret exceedingly having lost the notes of 
this most interesting case, and in order to avoid mistakes I 
will only state that, in an autopsy, made in the Allgemeine 
Krankenhaus, in October, 1852, on the body of a woman, aged 
about 50, the thyroid gland was found enlarged to four or five 
times its usual size, while the spleen was in every respect 
normal. I took blood from the abdominal aorta immediately 
above its bifurcation, and examined it with Dr. Heschl (first 
assistant to Professor Rokitansky), expecting to find in it a 
well marked excess of the colourless corj^uscles, hut it pre- 
sented no such apj)earance, while blood taken from the pulmonary 
artery contained so great an excess of these corpuscles that they 
filled the (jreatest portion of the field. 

It would be of course quite useless to attempt generalizing 
from two cases, and I would only suggest that, in all similar 
researches, the venous and arterial blood of the pulmonic, 
hepatic, renal, and glandular systems be examined sepa- 
rately, and that the account of the autopsy be as minute as 
possible, as this state of the blood may be connected with 
very many diseased conditions. 



On the Practical Application of Photography to the Illustra- 
tion of Works on Microscopy^ Natural History, Anatomy, S^c. 
By Samuel Highley jun. 

Many scientific phenomena, wlien first discovered, either from their 
roniarkability or beauty, have excited much interest in the popular 
mind, but have only been regarded by it as pleasing toys, till in 
the course of time their practical value has been discovered, and 
they have been arranged tliereafter in the list of applied sciences. 

Such was tlie globe of water, magnifying in distorted form the 
fly or flower, till in the hands of science it sprung into that exquisite 
refinement on optical tcnowlcdge, " tfie microscope," that discoverer 
of hidden worlds and life, and the seat or form of disease within the 
inmost walls of the human frame. Such the kaleidoscope, the tin 
case with its bits of coloured glass, regarded long, only as a 
wonder from the fair, till in practical hands we find ourselves in- 
«lel)ted to its aid for many of the beautiful geometric designs which 
ornament our walls or floors. 

So likewise was the camera-obscura, the discovery of Baptistii 
Porta, of I'adua, till the progress of chemical knowledge iliscovered 
to us the means of fixing its fleeting shadows ; and even then its 
product, together with its adjunct, the stereoscope, was little 



PRACTICAL APPLICATION OF PHOTOGRAPHY. 179 

thought of in its most valuable practical bearings ; but of late this 
has rapidly impressed itself upon us, and we cannot as yet see the 
limits of its utility. 

In Microscopy, Natural History, Physiological and Pathological 
research, what an invaluable agent will Photographic art prove ; 
for Nature here depicts herself with her own pencil, and, hi all 
probability, ere long from her own palette ; and in tliis resides one 
of its greatest values, for truthfulness is insured, and our studies 
delineated with a faithful and unbiassed hand ; and with what 
minuteness of detail, the photographs in this Journal bear witness. 
With regard to good photographs from the microscope, as we have 
presented to our view what the eye itself would only see if directed 
to the field of that instrument, we may expect many valuable 
records of histological research soon to be in circulation, to elicit 
further investigation. 

In delineating the peculiarities of the Geological features of a 
country, or of its Flora and Fauna especially, where species that 
could not be acclimatized to other regions are concerned, the 
naturalist will appreciate its aid. 

To the old complaint of the surgical anatomist, that little can be 
gained from flat plates, a new atlas may be opened by the applica- 
tion of stereoscopic principles to photographs of well-dissected 
surgical parts. 

To the physician it offers a means in many cases of conveying to 
the student an idea of tlie " Physiognomy of Disease," as already has 
been shown by Dr. Diamond's interesting collodion series of ' Types 
of Insanity ;' whilst in the accident ward, or the operating 
theatre, the exact delineation of many a curious and interesting case 
might, in a few seconds, be added to the records of its hospital, when 
time and the restlessness of the sufferer would not permit a drafts- 
man to exercise his art. 

Convinced of the value of this beautiful art, the offspring of phy- 
sical and chemical science, it is with a considerable degree of grati- 
fication that, as one of the Publishers of the Microscopic Journal, 
I am enabled to lay before the world in tiie plate which accom- 
panies Mr. Delves' puper its first practical application as a printing 
process to the illustration of scientific literature, a field where it 
will be mostly appreciated. And it is to the principles involved, 
and the processes and apparatus employed, that I devote this paper, 
for the information of those of our readers who may be unacquainted 
witii the details of Photography. 

Photographic phenomena are dependent on the power of certain 
rays, of which wliite light is composed, to effect the decomposition 
of certain chemical bodies when presented to their action. 

"When wliite light is decomposed by the refracting influence of a 
glass prisu), it is resolved into a spectrum, which appears to be con- 
stituted of seven rays, viz., violet, indigo, blue, green, yellow, orange, 
and red ; and the experiments of >Sir John Herschel and Profei^sor 
Stokes prove the further extension of the violet rays into lavender 
and spectral blue rays, and the red into a crimson ray, though these 



180 PRACTICAL APPLICATION OF PHOTOGRAPHY. 

are not visible to tlie unassisted eye. Sir David Brewster has, how- 
ever, proved that this spectrum consists only of three primary rays, 
blue, yellow, and red, which overlap each other, and thus by their 
combination produce the other spectra. These primary rays may 
be recognized in every part of the visible spectrum, and each seems 
to be possessed of a diiferent physical property : thus Tkermotic, 
calorific, or heating effects reside in the red rays, Light or luminous 
effects in the yellow rays, and the Actinic or chemical effects in the 
violet and the rays beyond it. 

Photography (light-drawing) and Heliography (sun-drawing) seem 
therefore to be inappropriate terms, since the light-giving rays are 
by experiment shown not to be the chemical agent in the pheno- 
menon, and artificial light produces actinic effects as well as the 
sun. But as, whenever photographic effects are produced, actinism 
is the agent, I would venture to suggest that the term Actinography 
would appear to be most correct. 

When surfaces prepared with agents sensitive to the actinic rays 
are exposed to light, a molecular change sets in, and the surface 
darkens all over ; if, however, we protect any part, as by inter- 
posing a piece of black lace or a transparent print, we obtain a 
faithful outline of the first and an imprint of the second ; but in 
both instances the natural appearance is reversed, for the parts 
exposed most to the light darken, whilst those parts protected 
remain white ; thus the black lace placed on light paper appears 
wliite on a dark ground ; wliilst in the picture all the lights appear 
as shades, and the shades as lights. Such prints are called Negatives, 
and wherever this interchange of blacks for whites or lights for 
shades occurs, the result belongs to this class. If, however, we 
again print from these, the dark ground or shades protect the 
surface tiiey are laid on, and they then resemble the originals ; such 
are called Positives, and this term is applied in all cases where the 
ligiits and shades are represented as in nature. 

When we are operating on transparent media, this power of 
reversing natural effects is of the greatest value, as it presents us 
with the means of obtaining what is analogous to engraved plates, 
from whicli we may print numerous copies, having all the effects 
true to nature ; and it is to this circumstance that the Collodion 
l*rocess offers such advantages, on account of the transparency, 
together with the modulations and depth of tone of the reversed or 
negatice pictures obtained. 

It is to tlie production of Collodion negatives in their application 
to natural iiistory and anatomical subjects, and the method of print- 
ing positives from them, that I devote the following description of 
th<! various operations ; and altliough these are described as when 
conducted under tlie most favourable conditions, this course is pre- 
ferred, that a guide may be given to others as to the general prin- 
ciples of the arrangements necessary, but which may be modified 
according to the position and circumstances under which they may 
be iihiced, or the extent to which tliey may feel inclined to carry 
their experiments. 



ENGRAVING, OR TAKING THE NEGATIVE. 



181 



ENGKAVING, OR TAKING THE NEGATIVE. 

The Oiieratingr Room, wherein tlie negative plate is taken, 
should be situated at the top of a house in a clear atmosphere ; if 
possible, it should command a northern and southern aspect : where, 
however, only one aspect can be obtained, the northern is preferable, 
as it is exempt during the greater part of the day froui the direct 
rays of the sun, and the actinic action over different times of the 
day is more uniform from this direction. This is divided into two 
compartments, — one, being the light room, contains the Object Table, 
the Background and Indicating Frame ; the other, the dark room, 
contains the Camera, the table, sink, and necessary materials for 
coating, developing, fixing, and washing the plate. 

The Lisfht Room is built of glass, with the exception of a 
skirting, which rises about two feet from the floor. Within the 
panels are fixal rollers with black and white blinds, arranged so 
as to give the operator a thorough command over the direction and 
amount of light admitted, as may be readily understood by reference 
to fiof. 1 . 




Fig. 1. 

The Object Table I have planned (T, fig. 1,) is so contrived on a 
cylindrical pedestal, that the object can be raised and lowered, or 
turned to one side or the other, with facility, so that different parts can 
be arranged at any angle that may be required, as when taking 
an anatomical view from a dead subject. 

The Back-sToiinil (G) usually consists of a short -napped 
blanket, or a piece of nankeen cloth stretched on a frame. This 
is suspended by rings on the rods R R, which run across the sides 
of the room, so that it admits of being adjusted at any distance 
from the object; it may either hang perpendicularly, or gradually 
slanting from the object, which gives the appearance of a receding 
background to the picture. The best effect, however, is pr<)(hu'e<l 
by using a very long and rough napped blanket, placed from tiiree 
to five feet behind the object ; and whilst the picture is being taken, 

VOL. 1. o 



182 PRACTICAL APPLICATION OF PHOTOGRAPHY. 

swinging it from right to left by means of a cord attached to the 
frame : this produces a clear transparent background, which throws 
the object out into bold relief with excellent effect. 

The Indicatinsf Frame (I, %• 1)1 have contrived, consists of a 
broad, flat, black wooden frame, on the sides of which are painted 
white letters or numbers, and a fine wire, having free movement, 
corresponds to each letter or numlier, so that, if its end is dropped on 
any particular part of the object, we can refer to it by giving the letter 
or number at its origin on the frame ; any other lettering, as the name 
of the object or that of the producers of the negative and positive, 
may be neatly written in with a chalk-pencil on the upper or lower bars. 
The top and bottom bars can be rt'moved and replaced witli others 
of different widths, so that the frame may be increased or decreased 
in width at pleasure. This is likewise suspended from the rods R R, 
and is so adjusted that the object is seen through it whilst the frame 
itself occupies the margin of the picture. By this arrangement the 
positive print gives a counterpart to which the type of the work it 
illustrates refers, and at the same time gives a finished appearance to 
the picture, wliilst it also saves the expense and trouble of afterwards 
engraving the references, &,c. on the plate. 

The Dark Room is separated from the light by black curtains C, 
which can be drawn from each side towards the centre, by the par- 
tition P, and a black blind B, which draws down, so that the room 
may be made impervious to white light, when the picture is to be 
made sensitive or developed. At other times the curtains and blinds 
are drawn together so as to cut off the light which comes from beyond 
tlie margin of the Indicating Frame. A window of glass, stained 
yellow by oxide of silver, or common glass with two or three folds of 
yellow glazed calico strained over it; or, according to Mr. Wilkinson's 
observations, a M'indow may be made of sheet India rubber, about 
1 -32nd part of an inch in thickness, is placed at the side for observing 
the development of the negative. The yellow media being employed 
to cut off the actinic rays from the light admitted, which would other- 
wise affect the sensitive plate. The sink is lined with gutta percha 
and drains off into a carboy placed for the reception of the washings, 
which contain silver, and are worthy of consideration in the econo- 
mics of large photographic establishments ; the water being at 
convenient opportunities evaporated off, the residue should be pre- 
served, till a sufficient quantity is collected, to reduce the silver it 
contains, or convert it into a useful salt. 

The Camera, or dark chamber, is usually constructed of well 
seasoned wahujt-wood, in a manner similar to that figured above. 

It consists of a ba.se-board A (figs. 2, 3), 18 inches long, to the 
und(;r surfivce of which are screwed three brass plates BBB 
(fig. 3) : to these the spring legs, hereafter described, are attached. 
To guard these plates and the clamp-screw /, a stout bead, about 
U inches deep, runs round the margin of the board, and is planed 



ENGRAVING, OU TAKING THE NEGATIVE. 



ib;^. 




Fig. 2. 




Fiff. 3. 



SO as to stand perfectly true on any level sui'face. To the base- 
board is attached the front of the camera C : this is square and 
6^ inches long laterally, into this slides D, the telescopic part of 
the back of the camera, which is 6 inches long. This should fit with 
great accuracy, that it may move smoothly and not admit any 
light uito the interior. D' is the part that receives the focussing 
glalB^ and plate-holders ; laterally it is 4J inches long ; in other 
respects it corresponds with the dimensions of the front of the camera 
C. The fop of this portion, E, is only about 3i inches wide, and is 
moveable, sliding in two horizontal dovetail grooves in the sides of D', 
leaving an aperture for the reception of the plate-holders, either at 
the back or towards the front of D', according as to whether it is 
pushed in the direction of the lens or drawn from it. f fare perpen- 
dicular grooves in the sides of D', into which the focussing- glass and 
the plate-holders are accurately adjusted, so that the plates and the 
ground glass may occupy exactly the same plane. By this arrange- 
ment, together with the rackwork movement of the lens, a range of 
foci, varying from 5 to 18 inches, are obtained. The replacement 
of the ordinaiy trap by the sliding trap E, I have found advantageous. 
In the front of C are two perpendicular dovetailed grooves, G G 
(fig. 4), into which slides the board carrying the lens F, which 
can be fixed by means of the clamp-screw IT, at varying heights. 
This movement of the lens allows the image of the object to be 
centered on the focussing glass witliout disturbing the parallelism 
of the camera to the object itself, as otherwise it would be necessary 
to resort to the objectionable mode of tilting the camera, to obtain 
a proper distribution of fore ground. The interior of the camera 
is usually blackened, but M. Laucherer states, that by whitening it, 
he ha.s found the time of exposing the plate lessened, and tliat 
there is greater uniformity in the distribution of the lights and 

o 2 



184 PRACTICAL APPLICATION OF PHOTOGRAPHY. 

shades in tlie pictures obtained ; but this method has been found 
by others to be olijectionable. 



™ 




Fig. 4. 

The Focussing: dlass consists of a plate of ground glass' fixed 
into a frame of wood about 1 inch in thickness, in such a manner 
that when the frame is dropped into tlie grooves /y, it shall exactly 
coincide with tlie position the prepared surface will occupy in tite 
plate-holders Avhen placed in the same grooves ; in other words, 
both focussing-glass and sensitive surface must be equally distant 
from the lens. The ground glass is ruled with squares and circles 
in pencil to correspond with the sizes and show the position tlie 
various sized plate-holders occupy in the camera ; and in focussing, 
the image of the selected portion of the object is made to occupy 
that sized circle which corresponds with tlie size of tlie plate on 
which the picture is to be taken. When tlie focussing glass can be 
used in the front grooves, the back part of D' serves as a shade whilst 
obtaining a sharp image of the object. In focussing, the rough 
adjustment is obtained by means of the telescopic movement of the 
camera; the fine adjustment, by the rackwork or sliding movement 
of the lens. 

After a satisfactory image is obtained, the back part of the camera 
is clamped by means of the screw I, which runs in a slit in the base 
board. 

The l*la(e-hoi«ier consists of a wooden frame (fig. 5) K, about 
1 inch thick, which exactly fills up the aperture that may be made 
in either the !)ack or front part of D', and the grooves//, into which 
it slides. Into this frame may be fitted two glass-plates,* between 
which sensitive paper is placed ; or these may be replaced by various 

* This or any otlior glass that may be interposed between the light and 
sensitive surface should be tested, according to Professor Stokes's recent 
oxperinients, to .see if it be of a kind tliat will cut off the actinic rays of 
the s])ectnim. 



ENGRAVING, OR TAKING THE NEGATIVE. 



185 



plate-holders suited for the different sized plates. These are made 
of oak slabs, of the thickness of the tivo glasses, having apertures 
cut through them suited to the size of the plate they are intended 
to hold, and of the shape sliown in fig. 5. Across the angles 
of these apertures are let four pieces of bhick glass, M M M M, of 
the same tliickness as one of the glass plates. On these comers is 
dropped the prepared glass or metal plate, N : the sensitive surface 



n— 



.0 




Fig. 5. 

thus occupies the same plane as paper would between the glass 
plates. A sectional view of glass and wood plate-holders is given 
in fig. 5, the references being tlie same as in the back view. In 
vertical side grooves, and in front of the holder and plate, works the 
slide or shutter of the frame O : tliis is hinged, so tiiat when it is 
drawn up, it may be bent over the camera so as not to be in the way 
whilst operating. A door hinged into the side of the frame, closes 
in the plate ; to the centre is screwed a spring, which presses the 
plate up to the proper position wiien the door is closed and hasped. 
Cameras are constructed in various ways, so as to render them 
simpler and cheaper, or more complicated and costly, but the form 
described is a very good type of what a working camera should be. 
What are called hinged portable cameras are just costly refinements, 
excepting where lenses of long focus or that cover a large field are 
employed, for as a certain space must be occupied by the chemicals 
and apparatus, &c. required for the various operations, this may just 
as well be arranged for in the interior of the camera, which then 
serves as a packing case, and is ready for use as soon as the box 
containing the materials is removed from it. If the form of the 
camera described is used for (ravelling, a handle should be let in 
flush with the top of C(fig. 2). 

The l^en-s. — Photographic lenses are of three kinds, the single — 
the single combination — and the double combination, — which are 
selected for use according to the nature of the object to be taken. 

The desiderata in a lens are, sharpness of definition over tiie whole 
of njlat field, depth, of definition, coincidence of the plane of cliemical 
or actiiuc focus with that of the visual ; in otiier words, tiie lens 
siiould be free from splicrical or (relatively) chromatic al)erration — - 
1 say relatively, for plioloyraphic lenses are not absolutely free from 



186 



PRACTICAL APPLICATION OF PHOTOGRAPHY. 



chromatic aberration, for part of the thermotic and the actinic rays are 
combined, those rays of the spectrum which produce the visual effect 
being present in the focus and in the same plane witli those which 
combine to produce the actinic effect, whilst lenses intended to be 
used visually combine only those rays which have the greatest 
intensity m producing light. 

As the term " achromatic^'' in relation to the correction of photo- 
graphic lenses, involves an erroneous idea, Mr. Hunt has lately 
proposed the term '■'■ diactinic" for those bodies which are trans- 
parent to the chemical rays, and " adiactinic" for those which are 
opaque to them. 

Spherical aberration is attributable to the incident rays M 
(fig. 6) not being equally refracted through different parts of the 
lens, the rays nearest the axial ray being less refracted than those 
nearer the marginal rays M, consequently they are collected at dif- 
ferent foci, as is shown in fig. 6 ; the result being a confused image 




of the ol)ject on tlic focussing glass, bright and sharp in the centre, but 
gradually jjassing off into a hazy halo towards the edge. Tiiis is 
dependent on the form of the lens — the greater its convexity, or the 
greater the inequality of the curves on its two faces, with reference 
to the direction of the incident rays, the greater will be tlie spherical 
alierration : it is tlierefore less in a lens of peri.scoi)ic form, which 
renders the marginal rays longer than the axial rays wlien the concave 
side is j)rcsented to tiie object. 

Spherical aberration is still further corrected by placing a dia- 
phragm, or stop, at such a distance before the lens that it will just 
admit the rays of light from the object and tlius exclude tlie margi- 
nal rays, as in fig. 8. In proportion, however, as we decrease the 
.si/e of th(! aperture of tiie stop, we increase the sharpness of the 
image and the size of the field, but tlie ojieration of expo.sing the 
sensitive surface i.>, proh)iiged in consequence of tlie amount of light 



ENGRAVING, OR TAKING THE NEGATIVE. 



187 



thus cut off. This decrease of actinic power, by the use of stops, is 
generally in the proportion of 1, 4, 8 — thus, cateris paribus, if with 
the largest aperture a picture was given in one minute, the smaller 
aperture wouhl require four minutes, and the smallest eight minutes, 
to produce the same effect. 

Chromatic aberration is dependent on the unequal refrangibility 
of each of the coloured rays into which white light is decomposed 
whilst passing tiirough the refracting substance of a lens. 

As the red rays of the spectrum are lea.st, wliilst the violet rays 
are most strongly refracted, it is evident that the violet or aciitiic 
rays, A, will be collected at a shorter distance from the lens than 
tlie red, or thermotic rays, T, as is shown in fig. 7. The space 
between A and T constitutes the chromatic aberration, and within 
it are situated, at various points, the intermediate rays of the spec- 
trum. At the point of intersection of the violet and red rays is 
situated the yellow or luminous rays and point of visual foci, L L. 




Fig. 7. 



If therefore we obtained a sharp image on a focussing glass placed 
at L L, it would be necessary to place the t^ensitive surface, at A, 
to obtain a photographic picture with an uncorrected lens: this dif- 
ference between the chemical and visual foci, in a single crown 
glass lens, usually amounts to about l-27th of its focal length. 

A simple mode of testing whether the visual and chemical foci 
are coincident, or the amount of aberration between the two, so that, 
in case of non-coincidence, the proper photogenic focus may b(^ 
indicated, is by placing the camera before a flight of miniature steps, 
numbered on their faces from 1 to 7 consecutively, then focus for 
number 4 the centre step, take a photograph of the steps ; if 4 
appears sharper than the other steps or numbers, the chemical and 
visual foci coincide; on the other hand, if a number nearer to the 
plate is most distinct, the chemical focus is sliorter than the visual, 
wliich indicates tliat the glass is under-corrected ; if a number furtlier 
from the plate is most distinct, the chemical focus is longer than the 
visual, which indicates over-correction, and the photogenic focus 
will then be behind instead of before the visual focus. 

AVhen lenses are used that have not these two foci coincident, a 
scale indicating the variation between the chemical and visual fijci 
at different focal lengtlis should be marked o\\ tiie draw-tube of the 
lens or tiie telescopic part of tiie camera. 

Chronratic aberration is corrected in sinah; lenses bv the form of 



188 



PRACTICAL APPLICATION OF PHOTOGRAPHY, 



the lens, the meniscus being the best, and by cutting off tlie mar- 
ginal rays, in which chromatic aberration is chiefly resident, by 
means of a stop, S, as is shown in fig. 8. 




Fig. 8. 

The most effectual mode of correcting cliromatic aberration is by 
conibinino;- two lenses of media possessed of different refractive and 
dispersive powers. This is usually effected by employing a double 
convex lens of crown glass, the refractive power of which will place 
the focus of the violet rays at v (fig. 9), and the red rays at r, 
and a plano-concave or double concave of flint-glass, the refractive 
)iower of which would place the violet rays in focus at v', and the 
red rays at r', the result being the recombination of the various rays 
into white liglit, and the production of an achromatic image at a 
mean point dependent upon tlie focal lengtlis of the two lenses. 




Tiie perfect correction of the chromatic aberration is solely de- 
pondeiit on the proper ratio of the curves of the flint to the crown 
glass lens, and, according to INIr. Ross's experience, diactinism 
can only l)e determined by trial with each individual lens. 

Tiie experiments of Professor Stokes, Malagiiti, and Sir John Her- 
schel, warn us tiiat care should be taken in selecting for the con- 
struction of piiotographic lenses such glass and cements as will not 
impede tlie actinic ravs. 

A rrj'racliie aberration is counnon to many lenses producing 
imai^es wherein straiglit lines are represented as bulged inwards or 
outwards. 'J'his dcffct is generally confounded with spherical aber- 
ration : whereas it is (le|)cud<'nt on the media of the lenses refract- 
inji luoie strongly at the marginal than at the central part of the 



ENGRAVING, OR TAKING THE NEGATIVE. 189 

lens, consequently bending outwards those portions of a line whicii 
are nearest the margin, and producing a pincushion shaped image of 
a square, or inwards producing a barrel shaped image of a square, 
according to the form and position of the lens. 

As the single lens is slower in action than the double combina- 
tion, but as it gives a larger field and greater depth of definition 
— by which term is meant the power of a lens to take in near and 
distant objects with equal distinctness * — it is therefore best adapted 
for landscapes and immoveable objects, as time, which is then of no 
object, can be allowed for bringing out the detail of the picture. 

Fig. 8 represents the section of a single lens or objective, 
which is used on account of being clieaper, and taking in a larger 
field. 



Fig. 10. 

Fig. 10 represents a single achromatic lens, in section, constructed 
according to the principles of correction described, with stops S ; 
cap. O ; and rackwork adjustment R. 

With the double combi/iution lens (fig. 11) two corrected lenses 
are employed ; and the aperture or diameter being greater in pro- 






Fig. 11. 



* The best instance T have seen of this is in Prctscli's view of Vienna, 
taken by a Eoss's lens, and exhibited at the late riiotoi];ni|iliie Exliibiliun 
at the Society of Arts. On the front, of a house, situated about /'(;«/• or six 
raik'n ilintnnt from those in the foreground, the name of the occupant 
is discernible. 



182* PRACTICAL APPLICATION OF PHOTOGRAPHY. 

portion to tlie focal length than in the single lens, it is more 
intense and quicker in action, therefore best adapted for taking 
portraits, pictures of animals, and other moving objects, tliough tiie 
image is considerably reduced in size. The references S, O, R in this 
sectional diagram correspond with those in fig. 10. 

Microscoiiic ObjectiTes usually consist of three, sometimes only 
two compound lenses ; but as they are over-corrected, the chemical 




Fig. 12. 
and vi>ual foci do not coincide, therefore must be compensated for. 
As it is important that the sensitive surface should be parallel to 
tlie object-glass, and having found difficulty in centering the body of 
the microscope to the camera, according to the mode recommended 
by Mr. Delves and Mr. Shadbolt, I have adopted the arrangement 
shown in tig. 12: a piece of tube is screwed into the flange of my 
photographic lens, and into a plate witii which one end is closed, is 
screwed the object-glass ; over this tube smootlily slides another, 
likewise closed at one end, but having an apeiture correspond- 
ing to that of the lens: to this is attached a piece 
^jgi^ of metal, on vvhicii slides the clamping slide-plate, re- 
moved from the stand of my microscope ; or two springs 
may be screwed to the front of tiie outer tube, the pur- 
I)ort of either being to hold the microscopical slide or 
object. A scale, showing the diffierence between the 
cliemical and visual foci, should be marked on the inner 
tube. With liigh powers a lever fine adjustment is neces- 
sary. To tho.se photographers who have not microscopes, 
this will be ftund an economical mode of adapting lenses 
to their cameras, as the stand of the microscope is dis- 
l)ensed witii. 

The Ntaiid, in its siuiplest form, is made by fixing 
three spring legs, of the construction shown in Fig. 13, 
into the brass sockets B B B (Fig. 3), and thus forming 
a steady tripod, which allows the Camera to be easily 
adjusted in any position, and combines the advantage of 
extreme portability. Tiiere are many other forms nuu'e 
expensive or iesii portable, but which have advantages 
under some circumstances. Amongst the latter is the 
I st<'reoscopic camera staml, wliich a(hnits of that instru- 
1,^,. Hi. incut being fixed at diHerent angles. 



ENGRAVING, OR TAKING THE NEGATIVE. *183 

Arraiis^in^ aud FocnssinsT the Object. — The proper position 
of the object can only be learnt by experience, as it depends upon 
an artistic appreciation of the arrangement of light and shade, com- 
bined witii a perfect knowledge of the chemical effect of light when 
radiated from surfaces of different colours. In ariatoniical subjects 
flaccid muscle should be padded up with cotton wool into a natural 
appearance of rotundity, the distinction between veins and arteries 
being obtained by employing coloured injections possessed of dif- 
ferent actinic actions ; and all parts that do not tend to a clear idea 
of the object should be cleanly cut away. A dark drab cloth 
should be thrown over the Object Table, to cover its mechanism, 
and to form a background to the object. After the object has been 
satisfactorily displayed, the uidicating wires should then be adjusted 
to any parts that are to be specially described. Skeletons may be 
suspended from the rods R R (Fig. 1) by cords, or supports, of 
the same colour as the backf/rozmd, to prevent their prominence in 
the pictuie. Shadows of window bars, &c., must never fall across 
the object. Living animals should be taken at favourable moments, 
as when dozing in a standing posture, or on the look out for food ; if 
wild, they should be induced to one end of a long, well-lighted 
den, whilst the lens is inserted between the bars at the other. 
Birds, reptiles, and some animals of a torpid nature, form very 
favourable subjects for operatiiig on. It should always be en- 
deavoured to get all parts of the object in as nearly the same plane 
as possible ; if this cannot be attained, a small stop must be inserted 
to obtain greater depth of definition with the lens, to prevent dis- 
tortion of the natural proportions. The light should fall in parallel 
rays on the object, and the Camera placed directly opposite it, and 
in such a position that strong rays of light do not fall upon the lens 
or intervene between it and the object. The lens should be adjusted 
so as to be perfectly parallel with the object ; and if this is near, 
atid inclines backwards from a plane vertical to the lens, a plate- 
holder working on an axis may be adjusted to a position parallel with 
the object. 

A simple mode of ascertaining whether the Camera is level is by 
placing a marble on its top ; when level, of course the marble will 
not roll in any direction ; this likewise apjdies to the levelling 
stands. When, by focussing, a sharp image of every part has been 
obtained on the ground glass, the Camera is clam|)ed, or, if working 
with an uncorrected lens, the variation between the two foci must 
first be allowed for. If a stereoscopic view of the object is to be 
taken, the Camera may be moved round about six degTees, to one side 
of a line central with the subject, and a particular part focussed on a 
fixed spot of the ground ghiss ; the camera is then moved round to 
a corresponding degree on the other side of the central line, the 
same distance from the object being preserved, and the same part 
again focussed on the same spot. The two Photographs, taken at 
different points of view, when viewed in juxtaposition stereo- 
scopically, resolve themselves into one image, with an a{)pearance 
of solidity and elevation. 



184* PRACTICAL APPLICATION OF PHOTOGRAPHY. 

With microscopic objects beautiful effects of light and shade may 
be produced by the employment of polarized liglit, as the varying 
thickness of the object (as in crystals of urinary salts, &c.) produces 
colours of different actinic action ; and with a Barker's selenite 
stao-e o-reat conmiand may be obtained over the colours desirable 
for producing the best effects by this mode of arrangement. 

Cleaning the Plates. — Perfect cleanliness being of the utmost 
importance, when the plates are first received from the glass 
warehouse they should be immersed in a bath of liquor ammonia 
and water in equal parts, that all traces of grease may be removed, 
or, if they have been previously used with iron developing solutions, 
they should be treated with a bath of two parts nitric acid to one of 
water, and afterwards thoroughly rinsed with pure water, A con- 
venient form of trough for these cleansing ojierations may be made 
of gutta perclia, the sides being grooved for the reception of each 
plate separately, so that the liquid may have free access to both 
surfaces of the phite. To suit plates of different sizes, a moveable 
grooved slab may be fitted to move across the centre of the trougJi, 
so as to advance or recede according to the width of the plates ; 
as soap contains grease it should never be employed. On remov- 
ing tlie plates from the water they are wiped with a perfectly clean 
linen cloth, then laid on a flat metal plate,* and polished off with a 
silk handkerchief, a circular motion of the hand being used : they 
are then put away in the stock box till required. Before coating 
the plate with collodion it should be finally polished by rubbing it 
on a doe-skin buff, about ten inches long by four wide, and then 
dropped into a wooden bowl, to prevent contact with any unclean 
surface. To preserve the buff from dust it should have a hinged 
cover, only to be kept open during the operation of polishing. 
The moment before applying the collodion the surface of the plate 
shoidd be lightly wiped with a cambric handkercliief to remove any 
trace of dust. 

<jiiaKN l*latcs. — The glass plates on which the negatives are 
taken should be of the best patent plate, about ~ inch thick, per- 
fectly free from any irregularity of surface, and cut to fit tiie pres- 
sure-frames best suited to tlie size of the page to be illustrated, and 
the edges then ground, 

lo«ii-#.4Ml Cuilodioii is a preparation of gun-cotton dissolved in 
a mixture of anhydrous ether and alcohol, and iodized with pure 
an<l white iodide of anunonium, or what is better, as it keeps longer 
and is more conveniently applied, the iodide of silver and ammonium. 
]5y varying the projmrtion of the alcohol this may be made to 
produce films of different thicknesses and degrees of tenacity. The 
^rreuter the (|iiantity the (juicker and more even is its action; but, 
if too much is added, it becomes attemmted, and then cracks and 
parts from the plate. If the film is to be transferred to paper, 

♦ Tlu; metallic surracc ])reveiils tlie accuinulatioii of any electricity pro- 
.liict.l by the fricliun of the silk, which otherwise would attract iioatiug 
paiticles tif dust. 




ENORAVING, OR TAKING THE NEGATIVE. *185 

blocks or plates, it must be of a very stout qualify. The neck of 
the bottle containing the collodion must always be freed from deposit 
before pouring any out. 

Coating^ the Plate. — Bend the forefinger of the left hand into 
an angle, with tlie tip pressing on the ball of the thumb; on this 
rest the corner of the glass plate numbered 1 in the annexed figure, 
and hold it firmly with the end of the thumb ; 
breathe on the glass to see if it is suflficiently 
clean and dry ; if so, the vapour will pass off 
instantly ; give it the final wipe with the cambric 
handkerchief, then bringing the glass into a 
horizontal position, pour the collodion plentifully on to the centre 
of the plate; incline the plate so that it will flow smoothly and 
gently into the corner marked 1, avoiding the thumb, then into 2, 
then 3, and lastly 4 (if the film appears too tliin, it may be again 
flushed up to 2, allowed to spread over the plate, and again returned 
to 4), when, without touching the neck, return the superfluous 
collodion to the bottle, bring the plate into a vertical position, 
and impart a tremulous motion to the plate along the direction of 
its longer axis, so that the ridges formed by draining may run into 
one another : pass the lip of the bottle along the edge from 1 to 4 
and from 4 to 3, backwards and forwards several times till all 
superfluous liquid is drained off: the result should be a perfectly 
smooth and even film. When the collodion is sufficiently set, and 
wliich can only be judged of from experience, it is ready for exciting. 

The SensitiTe Bath. — A gutta percha trough 1 inch across, 
and about the dimensions of the largest plate of your camera, is 
usually used for the sensiti^'e solution, and should be fixed obliquely 
on a block of wood, not perpendicularly as is generally the case, for 
this position facilitates the insertion and management of the plate. 
I, however, prefer the glass trough adapted to the camera, which 
holds the bath, in a position coincident with the focussing glass, as 
this arrangement certainly facilitates and shortens the operation. 
In either case a glass dipper may be vised, which is simply a strip 
of glass with another piece cemented across it, on which tiie plate 
rests. 

The trough is charged nearly full with a bath, wiiich may be 
prepared according to Mr. Ilennah's formula, in the following pro- 
portions : — 

Nitrate of silver . . .40 grains. 

Distilled water ... 1 ounce. 

Alcohol . . . .25 minims. 

Separate about an eighth of the quantity prepared, and to the greater 
bulk add, drop by drop, a solution of iodide of potassium till a preci- 
pitate of iodide of silver is formed ; agitate, and allow it to stand for 
some hours till the precipitate is dissolved ; filter, and then add the 
portion jjreviously set aside ; test with litmus paper, and if the bath is 
neutral add nitric acid, in the proportion of two drops to the pint — 



186* PRACTICAL APPLICATION OF PHOTOGRAPHY. 

prepare rather more of this solution tlian is absolutely required to 
fill the trough. When by use this bath is roljbed of its proper pro- 
portion of nitrate of silver, it may be again restored to its former 
streno-th by the judicious addition of a saturated solution of that 
salt. '^ When not in use, it should be kept in a bottle ; if in use, a 
lid fitted into the mouth of the trough, or the bath-frame of the 
camera, will preserve it from dust. When the temperature is below 
GC^ Fahr. the bath should be raised to tiiis point by placing it in a 
water-bath or by warming the room. The operating room, during 
the process of exciting the collodion film, must be preserved from 
the admission of white light, and yellow light only employed. 
The coated plate is rested on the dipper, previously moistened to 
promote adhesion, and with one steady plunge is passed into the 
bath. If there is the slightest pause, a line will be produced across 
the film, which will be imparted to the positives printed from it. 
After remaining in the bath for about a minute it is lifted in and out 
two or three times, and when the liquid flows evenly over the film it 
is sufficiently saturated ; it is then drained, the uncoated side laid on a 
pad of blotting-paper to remove superfluous moisture, and finally 
adjusted in the plateholder, with pieces of blotting-paper interposed 
between the corners of the plates and the glass rests (M, M, M, M, 
fig. 5). If the glass bath adjusted to the camera is employed, the 
plate may be coated in the open air ; and when the collodion is in a 
proper condition, the plate, resting against the sloping back of the 
i>ath, is plunged in, and the lid of the bath-frame shut down : in 
two minutes raise the lid and push the plate up to the front glass of 
the trough, so that it occupies a position corresponding with the 
plane of the focussing glass, and again close the lid, taking care 
(hiring this movement not to allow any light to fall into the bath, 
which may be obviated by throwing a black cloth or yellow hand- 
kerchief* over this end of the camera. 

Exposing' the Plate. — If operating in the rooms described, 
pull up to the required height the blind that shuts oiF the light 
from the room containing the object, and see that there is a sharp 
image on the focussing glass ; then fit the cap on to the lens, replace 
the focussing glass with the plateholder or bath-frame, raise the 
shutter of the frame (O, fig. 5), remove the cap of the lens and 
expose for the necessary time, replace the cap, close the shutter, 
remove the frame, and proceed to develop the picture as soon as 
possible. Tlie requisite time for exposure can only be judged of by 
experience, as it depends upon a knowledge of the action of the 
lens employed, whether single or double combination, the size of 
the stop, the sensitiveness or age of the collodion, and the nature 
of the light, colour of the object, and the temperature of the atmo- 
sphere at the time of operating; but it varies from a moment to a 
quarter of an hour. With a single achromatic lens, of 12 inches 

* A large voUow pocket-handkerchief will be found a very useful com- 
panion to a photographer when on a tour. 



ENGRAVING, OR TAKING THE NEGATIVE. *187 

focal length, 3 inches diameter, and A inch stop, from 10 to 30 
seconds will be, however, on an average, found sufficient. If a 
negative is required, it must be exposed longer than for a positive. 

neveloiiinsr the Ke§^atiTe. — On removing the plate in the 
darkened room no picture w ill be visible ; if it has been exposed 
long enough for tiie production of a negative, develop the latent 
image with the following solution : — 

Distilled water ... 8 ounces. 
Glacial acetic acid ... 4 drams. 
Pyro-gallic acid . . .12 grains. 

If there is any sediment after the pyro-gallic acid has dissolved, 
filter and preserve it in a bottle. Place the plate on a stand, 
having an arrangement of screws by vhich it may be brought to a 
level ; or the plan I employ saves the expense of this stand — across 
a glass plate, about 6 inches by 4, I cement a thicker strip about 
li inch from one end, to prevent the liquid flowing up to the 
fingers and staining them ; round the longer end I fold a piece of 
stout blotting-paper like a note ; when this is moistened it acts as a 
sucker when the plate is laid on it, and may be moved about by the 
hand without fear of its separating. Having, by either of these 
means, brought the plate to a horizontal position, pour out, into a 
perfectly clean glass measure, a quantity of the developing solution 
sufficient for the size of the plate, and for every dram add 2 drops 
of a solution of nitrate of silver in the proportion of 40 grains to 
1 ounce of distilled water. 

A plate 4 inches by 3 requires 2 drams. 
T 4. 4- 

J> " ?> ^ )5 ^ ■)■) 

5> " >J '^ » ' JJ 

Qi Hi 1 O 

Pour this over the surface, and if the plate is held on the sucker 
impart a gentle whirling motion to it, that a perfect dispersion of the 
liquid may be facilitated. The lights of the picture should appear 
first, and then the shadows, according to their depth of tone. 
Examine the progress of the development by reflected light, and 
when the details of the original are well defined pour off" the liquid, 
and wash in the horizontal position with a stream of cistern water 
poured gently over its surface. Never retain the solution on the 
plate after it has attained a dark brown colour ; and if the plate has 
been under exposed, which may be known by the picture appearing 
very slowly, and by the lights deepening before the appearance of 
the shades, it should be washed off" before the whites become opaque. 
If, on the other hand, both lights and shades appear instantly and 
about the same moment, with little difference of tint, the plate has 
been over exposed, and little can be done to make it useful. 

nevclopin^ the Positive. — If a positive is required, the pic- 
ture should have a shorter exposure in the camera, and be developed 



190 



PRACTICAL APPLICATION OF PHOTOGRAPHY. 



with the previous solution, to which a few drops of nitric acid has 

been added.* 

Fixing tiie Picture.— Cover the surface of the plate witli a 
saturated* sohition of hyposulphite of soda, and by daylight watcli 
the absorption of the iodide of silver, when every trace of this 
yellow salt has been dissolved, well wash it, and leave a body of 
water on the surface of tlie plate for twenty minutes, maintaining 
it in a horizontal position throughout this operation.-j- After the 
plate has been washed several times (for it is important that every trace 
of the hyposulphite of soda be removed, or it will crystallize and spoil 
the negative, as it would fade during the exposure when printing from 
it), it is drained, and, when perfectly dry, varnished with amber dis- 
solved in chloroform, which is applied in a similar manner to coating 
the plate with collodion ; the negative is then ready to print from. 

MAKING THE PLATES READY FOR PRINTING. 
For printing, negative plates are alone employed. The side 
coated with collodion is laid on the albuminized surface of the 
positive paper, pressure employed to bring them into close contact, 
and they are then exposed to the light till the proper depth of 
colour is obtained. The best form of pressure-frame is that sold 
by Newman, of Regent Street, as the pressure is very equally dis- 
tributed over the surface, so that there is little danger of breaking 
the glasses, and is thus constructed. A very flat, strong, well- 
seasoned board, with a cushion of cotton-velvet, padded with layers 
of flannel, is attached to two strong bars, which again fit into a still 

stronger bar, as will be readily 




I ® 



understood by considting the back 
and lateral views (Fig. 14). This 
cross-bar carries a screw at each 
end, over which a frame, fitted 
witii a plate of glass, about 3-8ths 
of an inch thick, and correspoiid- 
injr with the size of the cushioned 
board, drops, and which can be 
screwed down to any required 
pressure by means of the nuts fit- 
ting on to the screws. 

In the ordinary way each sub- 
ject is printed on paper, only a 
little larger than tlie size of the 
picture ; afterwards trimmed and 
mounted on paper ; but in the pre- 
sent instance it will be perceived 
that both views, together with the 
letterings, are printed on one sheet 
and by a single operation. 

* Sec also Mr. Shadlx)lt's Paper, Micro. Jonr., p. IHO. 
t A lovoUing stand may be readily funned of a gallipot and wedge of 
cork, placed in a dish or tray. 




Fig 14. 



EXGRAVIXG, OR TAKING THE NEGATIVE. 189 

For the purpose of saving time (an important point in the appli- 
cation of photography to the illustration of periodicals or other 
works) I found it necessary to contrive a special arrangement to 
attain this end ; and experience gained in working this out on the 
photograph? illustrating this Journal fully justifies tlie adoption 
of this method for the future. In a stout board, i-inch thick, 
square apertures, in proportion to the size of the page to be illus- 
trated, are cut, just deep enough to admit a piece of plate-glass, 
i-incli thick, and the negative plate, so that when they are inserted 
together, the glass is flush with the wood ; the thick plate, which is 
placed undermost, is rather larger than the negative, to allow of 
two beads fixing it down to the rabbet on which it rests ; within the 
beads the negative plate is cemented by its edges, collodion film 
uppermost. Above this is cemented the lettering-piece, which 
consists of a strip of glass, coated and blackened by the albumen or 
collodion process, and then engraved backwards and varnished ; 
this arrangement will be understood by examining Fig. 14. 

If the negative jjlates are too large for the work they are intended 
to illustrate, as was the case in the present instance, being about 6 
inches by 5, the best portion must be selected, the centre of this 
ascertained, and a circle scratched round it with the sharp point of the 
compasses ; the plate is then cut down with a diamond to the proper 
sized square. If the object would appear to best effect with a black 
border, as in the figure of the Trachese of the Silkworm, the collodion 
film must be carefully trimmed a^vay with a graver from the margin 
of the circle, then cleaned off with a cloth moistened with spirit, so 
as to leave the margin perfectly clear for the passage of light ; this 
consequently prints black ; on the other hand, when the subject i-^ 
dark, as the Proboscis of the Fly, and would be thrown up with the 
contrast of a white ground, a circle must be cut out of black glazed 
paper, the aperture adjusted to the circle containing the part 
selected, and the margin gvimmed down to the collodion side of the 
plate. 

Here I would suggest that if photography is found advantageous 
for the illustration of microscopical works, authors should adopt a 
plan similar to that found so convenient with object slides, of using 
a fixed scale of sizes for their glass plates, which must be determined 
by the sizes of the books they are intended to illustrate. A demy- 
octavo, with two negatives to the page, will only allow of the plates 
being 4 inches square ; a demy-quarto will take in four of these 
plates, or two plates 5 inches square ; a square octavo, one of the 
latter size. 

As by this ariangetuent of the pressure-frame, both the objects 
and lettering-pieces are printed on the same sheet of paper at the 
same moment, labour and time, which otherwise wouhl be neces- 
sarily employed in mounting them, are saved, consequently expense. 



VOL. I. 



190 PRACTICAL APPLICATION OF PHOTOGRAPHY. 

PRINTING THE POSITIVE. 
Albuminized Paper Process. 

The Positives, with which the present Number of this Journal is 
illustrated, are obtained by the albuminized paper process, whicli 
has been selected on account of the brilliancy of the lights, inten- 
sity of the shadows, and definition of the pictures it produces. 

The Paper should have a smooth surface, a firm and even' 
texture, weight from 12 to 24 lbs. per ream, of equal transparency 
throughout, free from spots of any kind ; not too strongly sized, — a 
starch- sized being preferable to a gelatine-sized paper; as chemi- 
cally pure as possiljle, free from watermark, and old paper should 
be selected in preference to new — the best papers for photographic 
purposes being those manufactured by Canson Freres, Turner, 
Whatman, and Lacroix. 

The quality of a paper is ascertained by examining it vertically 
before a light, and the side to be chosen is that which does not show 
any small square indentations : this, being the smoothest of the two 
surfaces, is selected, and, for future recognition, should be marked 
in pencil with the letter R. 

For the albuminized process Canson Freres' thick paper will be 
found the best, which should be cut in sizes, about 4 inch longer 
than the length of the picture required. 

The Albumen. In a large-lipped basin mix the following pro- 
portions : — 

The white of eggs ____-__i oz.* 
Distilled water - - - - -"- - -loz. 
Chloride of sodium ------- ^oz. 

Whisk this mixture up to a white froth with a wooden or ivory salad- 
fork, or, what is better, a bundle of three or four pens stripped of 
the feathers ; then skim with a wooden or ivory spoon, cover it with 
a glass plate, and let it stand for twenty-four hours. The scum 
that is formed on the surface at the end of that time should not be 
removed, as it protects the rest from dust. Make a small hole in 
this scum near the lip of the basin, and gently decant a sufficient 
quantity to cover tiie bottom of a gutta percha trough to the depth 
of i inch. The best troughs that I have seen are those sold by 
Henneman ; they are stamped in moulds, and are attached to slabs 
formed out of two pieces of well seasoned wood glued together in 
reverse positions of the grain : this effectually prevents warping, 
and secures a very flat bottom. As the internal surface is polished, 
it sliould never be wiped out with anything but a piece of fine sponge, 
and wiicn not in use sliould be kept filled with water. Remove any 
air-hui)blcs that may form on the albumen with a piece of paper, 
then fake (he pa|)er l)y two corners diagonally opposite, between the 
tips of the fuigers and thumbs ; lay one corner on the albumen, bend 

* One ounce e(inals the wliite of one egg. 



PRINTING THE POSITIVE. 191 

the paper backwards till It bulges out like a " squaresail " before the 
Aviud, lower the edge nearest the body gently on to the surface, and 
then, with an even and sweeping motion of the hand, carry forward 
the marked side of the paper over the surface of the albuuien till it 
floats flat thereon, taking great precautions that air-bubbles are not 
interposed, and that the paper never touches the bottom of the 
trough, as in either case it would be spoilt ; allow the paper to rest 
for two or three minutes, then with a reverse motion of the hand 
rip it off the albumen, allow it to drain from a corner, pin it by one 
corner on to a tape stretched across the room ; in a few minutes 
make a small piece of blotting-paper adhere to the lowest corner to 
absorb all moisture that may drain into it ; when dry, place it on 
three or four sheets of blotting-paper, and one sheet on the back ; 
then p ss an iron over it so warm that saliva just simmers on it. This 
coagulates the albumen, forming an insoluble size which renders the 
paper very tough. 

9fakin§r the Paper Sensitive. — In the dark room is placed a 
gutta percha trough, containing a solution* of — 

Nitr.ite of silver ------- 120 grains. 

Distilled water ------- loz. 

on which the albuminized paper is floated for two or three minutes, 
and then dried in the same way and w ith the same precautions as in 
t he former operations. When dry, the papers curl up into cones, 
like grocers' sugar papers, and in a similar manner may be packed 
one inside the other, and placed in a tin case till required for use. 

If protected from white ligiit, this paper will keep for about a 
week after its preparation. 

£xiiosing: in the Pressure-frame. — In the darkened room 
take the sensitive albuminized paper, spread it out flat, and adjust 
it on the cushion of the pressure-frame ; place the board into which 
the negatives are fixed over it, so that the coated surface of the 
plates is in contact with the sensitive side of the paper ; screw the 
two boards tight together, tilt the frame over into such a position 
that an equal beam of light falls upon the picture ; if in tlie direct 
rays of the sun, expose for about three minutes ; if iii (hfl'used light, 
from half an hour to one hour. The exact time for obtaining tlie 
tone required can, liowever, only be judged of by experience, as 
the depth of tone of the negatives o])erated with, and the amount 
and kind of light during the time of printing, must be taken into 
consideration. It is, however, better to over tiian under-print the 
positives, as the tone can always be reduced, but not increased, by 
after operations. 

Fixing-. — The positives must be finally fixed by carefully dis- 
solving out all the remaining chloride of silver they contain by 

* 'I'his pro])ortion may ho considered extremely strong, but Mr. Honne- 
uiau finds that it produces vigorous pictures witli rai>idity. The silver may 
be reduced to 100, 80, 50 grains, or less, l)ut tlu; cldoridc of sodium must 
he reduced in proportion. 

o* 2 



192 PRACTICAL APPLICATION OF PHOTOGRAPHY. 

immersing them in a bath of one part of a saturated solution of 
hyposulphite of soda and eight parts of water. The older this bath 
becomes the better are the tones obtained ; care being taken to add 
occasionally some fresh crystals of the hyposulphite to prevent its 
beiii'^ saturated with the salt of silver obtained from the positive 
previously treated in it, in which case its dissolving powers cease. 

Fixing- and Toning'. — Various tones, from India paper tints to 
pure black, may be given to the positives thus obtained, by treating 
them, after removal from the pressure-frame, with a bath of — 

Hyposulphite of soda - - - - - - 1 oz. 

Water - - - - - - - - -7oz 

Chloride of gold -------2 grains, 

contained in a gutta percha trough, the positive being placed with 
the picture uppermost. By this metjiod the positive is toned and 
fixed by the same operation. 

Watch the proof till the desired tone has been obtained, the posi- 
tives should tlien be removed, and afterwards washed in a succession 
of baths of warm water till every trace of hypos\ilphite of soda is 
removed. These washings usually require about six baths of a 
quarter of an hour each, and then a final one in distilled water. Too 
great care cannot be devoted to this operation being thoroughly 
performed, as otherwise the pictures fade in the course of time. 

On removal from the last bath dry the proofs by suspension ; 
wlien dry, smooth them out by passing a warm iron over the backs, 
or hot-press them ; the warmth also improves the tones of the picture, 
and glazes it. 

Havuig placed before the reader the various stages of the col- 
lodion and albumen process, it will be readily understood what 
advantages the former offers, for whilst by its aid we can obtain 
faithful delineations of such an object as the Proboscis of the Fly, 
irom the moment of coating the plate to its final varnishing, in less 
than a quarter of an hour, and at the cost of a few pence, the same 
subject engraved on wood, with an equal amount of minuteness, 
would occupy a wood-engraver a month, and at a cost of not less 
than ten pounds. On the other hand, the expense of the employ- 
ment of silver salts, and the time required in fixing the positives, 
considerably eidiances the cost of printing from them. 1 tru.st, how- 
ever, tliat photographers will see the necessity of devoting their 
attention to the perfection of some piinting process wherein cheaper 
sensitive materials can be employed, and i)robably some of the 
cliroviulcs would supply this desideratum : but such rapid and 
\ igorous rei-ults have been obtained by the employment of the silver 
salts, that there lia.s been little inducement to seek perfection by aid 
of other, though cheaper, agents. As yet the economics of the art 
have not come fairly l)efore them. 

Another cause, tending to make riiotograjjliic Printing expensive 
and inconvenient, is the entire dependence of the operator on fa- 
Ndurable weather ; ni(an> should, therefore, be adopted to render 



PRINTING THE POSITIVE. 



193 



him independent of natural light, and little difficulty would, I 
think, be experienced in arranging- a ditiused artificial light suitable 
for photographic purposes ; and the aim should be to produce a 
bluish violet-coloured flame, not an intensely white or yellow one. 

It will be seen that the photographer occupies the position of the 
draftsman, engraver, and printer of ordinary processes ; but the 
analogues of drawing and engravmg being performed at one and the 
same moment suggests a division of labour between the Photo- 
graphic Artist, who would devote his attention to the artistic prin- 
ciples of the subject and the production of the negatives, and the 
Photograpliic Printer, who would conduct the processes for the pro- 
duction of positives ; and this branch should be conducted on an 
extensive scale, with division of labour, but this not of an expensive 
kind, as children or girls might be employed with advantage ; and, 
as mechanical means generally facilitate labour, a photographic 
press, of the following construction, might be employed. A flat 




board, with beaded edges, carries two upright supports for the axis 
of a glass cylinder, covered with a few layers of cloth ; this is kept 
saturated with the sensitive solution by a reservoir attached to one 
of the uprights, the bottom of which is prolonged into a tube drilled 
with a row of holes, from which the liquid flows on to the cylinder 
according to tlie amount of atmospheric pressure exerted on its sur- 
face, which is governed by the admission of air into the reservoir, by 
means of a stop-cock attached to its neck. The paper is laid on a 
cushion, sliding between the beads of the base board, and a silver 
plate, with apertures corresponding to the size of the surface to be 
made sensitive, is brought down on it ; it is then passed under the cy- 
linder, which has previously been regulated to the proper amount of 
pressure, by screws affecting the springs on which its axis rests, the 
paper is then removed, and that part only whicli is to be acted on 
will have been made sensitive instead of the whole of its surface, 
thus preventing the absorj)tion of more liquid than is necessary. 

In many instances collodion films may, with advantage, be 
transferred to wood, metal, or stone, and thus save tiic drafts- 



194 PRINTING THE POSITIVE. 

man's labours altogether. When metal plates, however, are to be 
engraved from photographs, the employment of the daguerreotype 
process would be more advantageous, the practicability of which 
has already been demonstrated in Donne and Foucault's " Cours de 
Microscopic complementaire des Etudes Medicales," published as 
early as 1846. 

In concluding this article, I beg to offer my sincere obligations 
to Mr. Delves for liis liberal and valuable aid in furnishing, for 
this Number of the 'Microscopical Journal,' the requisite number 
of negatives from which the positive proofs were produced by 
Mr. Henneman of Regent Street ; also to Mr. A. Ross and Mr. 
Henneman, for their kindness and readiness in affording me infor- 
mation on lenses and practical photography. And if, in describing the 
various operations, I have risked appearing diffuse, it is because I am 
convinced that success in these processes depends upon the minutiae 
and niceties of the manipulations, but which, however difficult they 
may appear in type to the uninitiated, after a few trials will come 
readily to hand, and, with moderate attention, will be rewarded with 



( 195 ) 



TRANSLATIONS. 



On Unicellular Plants aiid Animals. By C. Th. v. 
Siebold. From Siebold and Kolliker's Zeitsch., f. w. 
Zool. Bd. 1, p. 270. 

(Continued from page 121.) 

Respecting the motions, which have been frequently noticed 
in unicellular Algae, Nageli observes very truly (p. 19), that 
they present nothing of a spontaneous or animal character, 
since they arise, not in the contraction or expansion of the 
membrane, excited by an external or internal irritant, but 
proceed singly from the vegetative processes of absorption 
and excretion of fluid, and the formation and solution of solid 
matters. Of the four categories of these plant-motions dis- 
tinguished by Nageli, we are here interested only in the third 
and fourth, since it is precisely those which have been con- 
founded with animal movements. 

The slow forward and backward movement, which has been 
observed in several Diatomacea^ and Desmidiaceae, is explained 
by Nageli (p. 20) in the following satisfactory way : — " The 
cells have no special organs for these movements. But as, in 
consequence of their nutritive processes, they take it and give 
out fluid matters, the cells necessarily move, when the attrac- 
tion and the emission of the fluids is unequally distributed on 
parts of the surface, and is so active as to overcome the re- 
sistance of the water. This motion, consequently, is observed 
more particularly in those cells which, in consequence of their 
taper forms, easily pass through the water ; these cells, more- 
over, move only in the direction of their long axis. If one 
half of a spindle-shaped or ellipsoidal cell chiefly or ex- 
clusively admits material, the other half, on the contrary, 
giving it out, the cell moves towards the side where the ad- 
mission takes place. But as in these cells both halves are 
physiologically and morphologically exactly alike, so it is that 
it is first the one and then the other half which admits or 
emits, and, consequently, the cell moves sometimes in one, 
sometimes in the opposite direction." 

In this way may be explained, perhaps, all those motions, 
which are so readily noticed in the Bacillariae. Only a com- 
plete misconception of these plant-motions could have induced 
Ehrenberg to seek for motile organs in these organisms. 
According to him, it would appear, for instance, that the 



196 STEBOLD ON UNICELLULAR PLANTS AND ANIMALS. 

Naviculariae can project an undivided motile organ like the 
foot of a snail from one of the central openings of the shield. 
•This pedal organ is said to lie constantly closely applied to 
the shield, but to admit of its being extended as far as the two 
extremities. I have never been able to detect this organ in 
any Navicula, nor has Kiitzing, with his utmost endeavours, 
succeeded in the finding of it. As, on the other hand, Schmidt 
and Eckhardt (Wiegmann's Archiv, 1846, Bd. I, p. 212) have 
been more successful and have seen this remarkable foot, 1 
can only oppose to this the following observations. Ehrenberg 
states, that in Navicula there are six rounded openings upon 
the dorsal and abdominal surfaces — four at each end and two 
in the middle. Of the four openings at the ends, the two on 
the abdominal surface are said to he oral openings, and the 
two on the dorsal, respiratory, whilst the central opening of 
the abdominal surface is stated to be for the protrusion of the 
foot. In Navicula fuha Ehrenbeig supposes that a similar 
foot-like organ is protruded also from the dorsal opening. 
How Ehrenberg has been thus deceived I know not, but in 
contradiction to all these various erroneous notions, I can only 
say this much, that these six openings in Navicula have no 
existence whatever, but that precisely in the spots at which 
Ehrenberg and others suppose they have seen six openings, 
the siliceous cell-membrane is thickened and consequently 
forms so many rounded eminences which project internally. 
It is, therefore, needless to say, that there can no longer be any 
question about either oral or respiratory openings, nor of 
openings for the passage of a motile organ. On the same two 
surfaces, upon which the six round thickenings of tlie siliceous 
shield of Navicula are placed, there are observable, on the 
contrary, four lines, running along the middle of the surfaces 
from one thickening to the other. These lines, which have 
been long known, but hitherto apparently but little noticed, 
are to be referred to a suture, fissure, or rather gap, in which 
no siliceous matter is deposited, so that in these places the 
delicate primordial membrane which lines the siliceous shield 
can be brought in close relation with the external world. 
I come to this conclusion from the circumstance that it is 
exactly at these four sutures or fissures that the water sur- 
rounding the Navicula is set in motion. The existence of this 
current is readily demonstrated if some minute solid particles 
are added to the water in which are some fresh Naviculae. 
Indigo is the best for this purpose. When water thus coloured 
with indigo has come to a state of rest on the object-glass, it 
will soon be perceived by the microscope that those particles 
oi indigo which come in contract with the living Navicuhv 



SIEBOLD ON UNICELLULAR PLANTS AND ANIMALS. 197 

are set into a quivering; motion, alihough previously quite 
motionless. It will, moreover, be perceived that only that 
indigo is set in motion which is in contact with the four 
above-described sutures of the siliceous shield, whilst the 
particles of indigo adherent to the other parts of the shield re- 
main altogether motionless. Besides the quivering movement, 
another very striking motion is perceptible in these indigo 
particles, which, when they come in contact with the sutures 
of the siliceous shield, are forced pretty rapidly up and down 
upon it. The indigo particles, which are propelled from the 
terminal towards the two central eminences, are never observed 
to pass beyond the latter ; at this point there is always a quiet 
sj)ace, from which the particles of indigo are again repelled in 
a reverse direction towards the extremities. This proves that 
the linear sutures, as may in fact be seen, do not extend over 
the central eminences of the shield. The current at these 
clefts is occasionally so strong that proportionally large bodies 
are set in motion by it.* 

These movements did not escape Ehrenberg, when he 
endeavoured to feed the Naviculaceae with indigo, although 
he explained them erroneously, attributing the attraction and 
repulsion of neighbouring substances, in the case of Naviculae, 
to the pedal motile organ. Moreover, that Ehrenberg had not 
apprehended these movements with full attention, is evident 
from the figures above cited, in which he indicates that the 
indigo on both surfaces of a Navicula viridis passes beyond 
the central eminence. It is to be regretted that Nageli, in the 
paper here quoted, has not s^ibjected the Diatomaceae to any 
special investigation, from which we should undoubtedly have 
gained much information respecting these unicellular or- 
ganisms. 

The fourth sort of movement noticed by ISageli (p. 20) in the 
unicellular Algae is of most especial interest, viz. the " Swarm- 
ing," which occurs in many Palmellaceae, Protococcaceae, and 
Vaucheriaceae. He remarks very correctly that this " Swarm- 

* I will take this opportmiitj- to remark that water coloured with indigo 
is ail excellent means for the study of the remarkable plant motions of the 
Oscillatoria^ which liave heretofore been regarded as of an animal nature 
by various naturalists. These plants allbrd a very interesting sight when 
thus examined. The particles of indigo which come in contact with the 
single filaments of the Oscillatoria arc propelled in a tolerably close spiral 
along the filament to its extremity. Whether the filament itself continues 
to move or is cpiiescent, it was ei[uall)^ striking to me to notice that occa- 
sionally this spirally gliding motion of the indigo took place from each 
end of a filament towards the middle, in cases where the colouring matter 
was agglomerated into a ball, or that this motion sometimes ])roceeded in 
a reverse direction from the middle of a filament towards each end. 
VOL. I. P 



198 SIEBOLD ON UNICELLULAR PLANTS AND ANIMALS. 

in^" is a phenomenon identical with tliat observable in the spo- 
rangia of the multicellular Algae {Ulotkrix, Conferva, Chceto- 
phora, (Sec). I must here, in passing, remark, that Nageli, 
Thuret, &c., when speaking of " Swarm-spores," do not thereby 
understand any sort of moving corpuscles accidentally met with 
in the water, and arbitrarily taken for vegetable forms, just as 
similar corpuscles in the water have been arbitrarily considered 
as animals by Ehrenberg. These naturalists have rather ob- 
served the development of these Swarm-cells or spores within 
their mother-cells, in uni- or multi-cellular Algae, and have dis- 
tinctly satisfied themselves of the vegetable origin of these 
free-swimming corpuscles. In this way it was not left to the 
subjective judgment of the observer to decide, according to the 
impression he might receive, whether these corpuscles are 
plants or animals. Ehrenberg, therefore, is in error when he 
pronounces the Swarm-spores of Algae, the development of 
which he has not observed, to be Infusoria ; and Thuret is in 
no way to be blamed, as he is by Eckhardt (o/j. c, p. 214), 
in his figuring moving bodies (supposed Infusoria), which, 
however, he saw developed in the cells of Algae, and escaping 
therefrom, as spores of Algae, 

Nageli (p. 20) thus expresses himself with respect to the 
Swarming of unicellular Algae: — " It is usually the solitary 
individuals that swarm, rarely the families consisting of several 
individuals. The SAvarm-cells have, for the most part, an 
ovoid or short pyriforrn, rarely a spherical figure ; they have 
at the narrower colourless extremity two or four, or a circlet 
of very delicate cilia, or are covered throughout with similar 
cilia. Under the microscope the motion appears very rapid, 
somewhat of an infusorial character, consisting in a conti- 
nual progression, in which the hyaline, narrower extremity is 
usually in front, and the cell is continually turning on its long 
axis. Although the swarming bears a resemblance to the 
motion of Infusoria, it is clearly wanting in the spontaneity of 
the latter. The Infusoria advance, spring back, turn round, 
return, all spontaneously ; the swarm-spores pursue (p. 21) 
a uniform and, for the most part, pretty straight course, de- 
viating from it, or turning round only upon meeting an ob- 
stacle, impinging upon which they are diverted into another 
direction. Px^sides this, the wall of the swarm-cell, although 
extremcily delicate, is yet impassive and motionless, whilst in 
llie Infusoria, either the membrane is manifestly contractile, 
or its ajjpendagcs (cilia) are motile." 

I entirely agree in this representation and explanation of the 
" swarming in the unicellular Algae, which is also entirely in 
accordance with what tnkes place in the multicellular Algae, 



SIEBOLD ON UNICELLULAR PLANTS AND ANIMALS. 199 

and have already so expressed myself (De finib. inter regnum 
animale et vegetabile constltuendis. Erlangae : 1843). Only 
I cannot concur with Nageli when he makes a difference be- 
tween vegetable and animal cilia, saying that the former, the 
delicate plant cilia, are rigid, or admit of only passive 
movements, whilst the animal cilia alone are said to possess 
the faculty of spontaneous motility. To this Nageli adds 
(p. 22), that although it is true the cilia do move in otherwise 
entirely rigid swarm-spores, yet he denies that they are the 
cause of the motion of the swarm-cells, because there vibra- 
tion is only the natural consequence of the current in the water 
produced by the active endosmosis and exosmosis of the cells. 
According to Nageli absorption, is effected at the hyaline ex- 
tremity corresponding to the root end of a plant, by which is 
explained the fact that the swarm-spore swims with that end 
in front, attraction being set up at that extremity, and repul- 
sion at the other, owing to the resistance of the water to the 
fluids emitted. As far, perhaps, as the direction of the 
motion of the swarm-spore is concerned this explanation would 
account for it ; but I very much doubt whether an end- 
and exosmotic process, however active it may be, would of 
itself account for the quick and often extremely rapid move- 
ment of these spores. The vibration of the cilia which, in 
my opinion, plays the principal part in the movement of the 
spores, is explained by Nageli to be the natural consequence 
of the currents in the water, the cilia being so delicate as 
necessarily to be affected by the slightest fluctuations. In con- 
tradiction to this, however, I must remark, that the fre- 
quently rather long cilia are almost always extended, with a 
lashing motion, in the same direction as that in which the 
spores proceed ; which could not be the case with such deli- 
cate and flexible organs unless they exerted a power of spon- 
taneous motion. I cannot dispute, however, that the immo- 
tility and impassiveness of the vegetable cell-membrane, as 
Nageli properly remarks, is a general law without any excep- 
tion, but I am by no means satisfied, that from this motionless 
and impassive or rigid membrane are developed the motile cilia 
of the swarm-spores. With respect to this, however, Nageli 
argues, that even the vegetable spermatic filaments have an 
impassive form, and advance merely in consequence of their 
turning around their axis. To this I would object, that the 
remarkable and very active motions of the vegetable spermatic 
filaments, according to the most recent discoveries of Thuret, 
Decaisne, and Suminski, are caused by two or several long 
motile cilia which are attached to one extremitv of these 

p2 



200 SIEBOLD ON UNICELLULAR PLANTS AND ANIMALS. 

entirely impassive spermatozoids.* In this we perceive an 
important distinction between the formation and movement of 
the vegetable and animal spermatic filaments, the former bein^ 
self motile, whilst the latter are moved only by the aid of 
vibratile cilia. 

It appears that Nageli is inclined to raise a distinction be- 
tween vegetable and animal cilia, principally because otherwise 
it would be necessary to assume the existence of contractility 
in the former. I would maintain, however, that neither the 
vegetable nor the animal cilia, between which I can perceive 
no difference, are to be regarded as delicate contractile fila- 
ments. In the actively-moving vibratile cilia particularly, as 
well as in the animal spermatozoa, the movements proceed in 
a way as yet altogether unknown ; from a simple waving and 
bending action, unattended by any shortening or lengthening, 
and without any thickening or attenuation of the filament, 
whilst the delicate non-vibratile, but undoubtedly contractile 
(animal) filaments, during their movement become at the same 
time shortened and thickened, or elongated and attenuated. 
It is true that Unger describes, with respect to the ciliated 
organ of Vaucheria, a retraction and shortening of the cilia or 
spores, from the influence of a solution of sugar. But the 
result of this experiment in no way goes to show the con- 
tractility of these excessively delicate cilia, as it was not 
observed during their life, and must undoubtedly be con- 
sidered as a process of decomposition ; in support of this is 
the fact, as Unger expressly reinarks that the coarser cilia, 
on the branchiae of Unio, though, indeed, rendered motionless 
by the same treatment, nevertheless do not become shortened. 

The movement of the swarm-spores in general have only a 
short duration. After the spores have come to a state of 
rest, they usually become attaclied by the hyaline-ciliated ex- 
tremity, and the locomotive faculty is for ever lost. That 
these spores should move toward the light, cannot be wondered 
at when we consider the hungering after light so generally 
observable in the vegetable kingdom. 

With respect to the motion of the spores, I must again re- 
mark upon a phenomenon above described by Nageli, and 
wliich is one of a very evident nature, viz., tliat these bodies 
are impelled involuntarily, and proceed always in one direc- 
tion, and witiiout resting. If in this course tliey strike upon 

♦ Vide Tliurot on Chara ; Ann. d. S. Nat. i5ot., torn. 14, 1840, p. 67, 
I'l. 7, and Dc-caisnc and Tlnirct. ]h. torn. 3, 1K45, p. 8, PI. I & 2 ; .n 
varidu.s fucoids. Suminski, Kntwickchin^s-Gcscliiclitc der Fairnkraiitcr. 
IJorlin, 184H, p. 11, PI. II. 



SIEBOLD ON UNICELLULAR PLANTS AND ANIMALS. 201 

any larger object, they do not retreat from it frightened as it 
were, as do the Infusoria not unfrequently, but they impinge 
directly upon the obstacle, remain close to it, and continue 
their motions, according to the number and arrangement of 
their ciliary apparatus, in a rotatory or vibratory way for a 
little time longer, as if they aimed at overcoming the obstacle 
by force, until at last, probably in consequence of the death 
of the cilia, they become still, and germination goes on, so 
that the swarm-spores belonging to certain multicellular Algae 
make use at the same time of one and the same object as a 
basis, to which they become affixed by warty processes, pro- 
jected from the hyaline extremity. 

In several unicellular Algae, particularly in those which 
*' swarm " united into families, that process endures very much 
longer : in some species, indeed, the " swarming ^' families 
continue almost their whole life through in the same con- 
dition ; this is the case in the Volvocina, in which, even during 
the " swarming," new " swarming " families are produced, or 
do not come to a state of rest until the period of [true] pro- 
pagation has arrived. 

How strikingly the swarm-spores, both of unicellular and of 
multicellular Algae, resemble certain Monadina and Crypto- 
monadina is well seen in the representations of various spores 
of this kind, given by Unger, Thuret, Solier, and Niigeli. It 
is well known that Unger (' Die Pflanze im Momente der 
Thierwerdung,' 1843, figs. 8, 10) discovered that the motion 
of the spores in Vaucheria clavata was effected by a general 
ciliary investiture, a discovery which was confirmed by Thuret 
(' Recherches sur les Organes locomoteurs des Spores des 
Algues, Ann. d. Sci. Nat. Botan.,' tom. 19, 1843, PI. II., 
figs. 29, 30). The same observer (ib., PI. X., figs. 13, 14, 18) 
noticed a circlet of cilia in the " swarm-spores " of Prolifera 
(^Conferva) vesicata, alternata, tumidula, and Candolii, as did 
Solier (Memoire sur deux Algues Zoosporees, ib., tom. 7, 
1847, PI. IX., fig. 8-1 1 and 2.3) in Derhesia {Bri/opsis) ma- 
rina, and Lamourouxn. According to Tlmret (ib., PI. X., 
figs. 1-3 and 7-10), the zoospoi-es of Conferva fflomerata 
and rivularis swim about with the aid of two lash-like cilia, 
and those of CluBto'phora elegans, on the other hand, with four. 
Nageli figures the zoospores of Aj)iocystis Brauniana, Nag., 
of Tetraspora explanata, Kiitz , and Characium Ndf/elii^ Br. 
with two such cilia. Fresenius (Zur Controverse iiber die 
Verwandlung von Infusorien in Algen, 1 847, figs. 1-3) de- 
tected in the biciliated zoospores of Cluetophora eleijans, also 
the (so termed) red " eye." According to the highly interest- 
ing reseai'ches of a A. Braun (Verhandl. der Schweizerischcn 



202 SIEBOLD ON UNICELLULAR PLANTS AND ANIMALS. 

naturforsch. Gesellschaft zu SchafFhausen, 1847, p. 20), a 
formation of spores occurs in Hi/drodictyon utriculatum, in 
consequence of which, zoospores, with four long cilia and a 
red granule in the interior, swim about with great activity. 

How extensively, again, these zoospores are present among 
the Algae, is shown in the numerous researches of my friend 
A. Braun, here in Freiburg. 1 can here only refer to his 
memoir just quoted, which will show what an abundance of 
materials he has already collected on this important subject, 
and how interesting it would be to science were he to resolve to 
publish these discoveries in their whole extent. From the me- 
moir above noted it is to be gathered, that in Conferva glomerata 
and fracta numerous spores, with two cilia and a (so called) 
red " eye " spot, quit the mother-cell, through an opening 
which is formed in a definite spot. In UlotJirix zonata, Kiitz., 
he saw formed in each cell from eight to sixteen spores, fur- 
nished with four cilia and a large round " eye," which escaped 
through a lateral opening in the mother-cell, enclosed in a 
delicate vesicular membrane, and did not swim about until 
this membrane was ruptured. In Draparnaldia mutabilis, 
Stygeoclonium tenue, and several allied species, as well as in 
Chcetophora tuherculata, according to Braun's researches, there 
is in each mother-cell only a single red-eyed spore, with four 
lash-like cilia. Braun, moreover, confirms Thuret's pre- 
vious observations on other Confervae, and describes also the 
propagation of the unicellular algan plant, Characium Sieboldi, 
Br., in the spindle-shaped mother-cell of which, sixteen and 
more spores with two cilia become developed ; and also men- 
tions a Protococcus versatilis, Br., the cells of which, after 
their attaining a certain size, divide into two motionless cells, 
which, by repeated segmentation, divide into four, and these, 
in like manner, into eight ; which last — fourth generation — 
swims about for a short time by means of four vibratile cilia, 
in order eventually again to go through the motionless cycle 
of vegetation. 

Another distinguished work, already several times quoted, 

Ralfs' British Desmidieae,' also treats of unicellular plants, 

wliich have been confounded with lower animals, although in 

H more limited sense, embracing only the Desmidiaceae and 

(Jlostcrina of J'lhrenberg. 

Kespe( ting the remarkable process of segmentation, by which 
most of the Desmidiaceae are multiplied, Ralfs remark (p. 5) 
that the segments gradually enlarge whilst they divide, but 
tliat this multiplication by division has its limits, for, after a 
certain number of generations, the individuals which had by 
repeated division attained a certain size, at last perish. 



SIEBOLD ON UNICELLULAR PLANTS AND ANIMALS. 203 

- A most especial service has been rendered by the same 
assiduous observer of the Desmidiaceae in his investigation of 
the process of conjugation in so very many of these unicellu- 
lar plants. This process had been previously described by 
him (Ann. Nat. Hist., vol. xiv., 18-14, p. 258, P. viii., and 
vol. XV., 1845, p. 153, pi. X.) in Tetmernorus granulatus, R., 
and Staurastrum mucronatum, R. In his recent work we learn 
that the same proceeding takes place, besides the Closterina, 
in many other Desmidiaceae, viz. Hyalotheca^ Didymoprium^ 
Sphcerozoma, Euastrum, Micrasterias, Cosmarium, and Xan- 
thidiuni. In the moniliform HyalotJieca dissiliens, R., and 
Didynioj)rium Borreri, R., the conjugation takes place in such 
a way that two contiguous cells separate on the sides oppo- 
site each other, and through the cleft their contents escape in 
order to form a common sporangium. In the permanently 
unicellular forms of the Desmidieae, with the exception of 
certain Closteria already mentioned, two closely approximated 
individuals dehisce transversely in the middle, and yield up 
their whole contents to the formation of a single sporangium. 

The sporangia of the Desmidiaceae thus originating in 
conjugation have for the most part a spherical form, and, 
according to Ralfs (p. 10), in many species I'emain smooth 
and unaltered, whilst in many others they become granulated, 
tuberculated, or spinous, many eventually acquiring a Xan- 
thidian figure. 

It is to be regretted that Ralfs and Jenner have not as yet 
succeeded in tracing the further development of the Desmi- 
diaceae within these sporangia. From the coloured figures in 
Ralfs' work, it appears that the green contents of the sporangia 
in certain Desmidiaceae in time become red. Whether this 
phenomenon be connected with a further development of the 
contents, and perhaps corresponds with the transformation of 
the Chlorophyll into an orange-coloured oil, as described by 
Nageli, 1 must leave undecided. [Here follows an abstract of 
Mr. Ralfs' excellent observations on the question of the 
vegetable or animal nature of the Desmidieae ; but as his 
valuable work is probably in the hands of, or attainable by, 
all who may feel an interest in knowing what such an ac- 
curate observer and careful ' reasoner says upon this subject, 
it seems needless here to give the abstract.] 

A very important discovery recently made by Thwaites 
(Annals Nat. Hist., vol. xx., p. 1847, p. 9, and 343, pi. iv. 
and xxii.), showing that conjugation takes place also in the 
Diatomacea*, cannot here l)e passed over. He observed in 
Eunotia tnryida and Zebra, Ehr., as well as in Epithcmia 
yibba, Kiitz., and Fragilaria pectinalis, »Scc., the following 



204 SIEBOLD ON UNICELLULAR PLANTS AND ANIMALS. 

remarkable phenomenon. Two individuals, closely approxi- 
mated, dehisce in the middle of their long diameter, where- 
upon four protuberances arise, which meet four similar ones 
in the opposite frustule. These indicate the future channels 
of communication by which the endochrome of the two 
frustules becomes united, as well as the spot where is subse- 
quenth' developed the double sporangium, or rather the two 
sporangia. The masses foimed by the coalescence of the two 
portions of endochrome shortly become covered each with a 
smooth cylindrical membrane — the young sporangia. These 
gi'adually increase in length, retaining nearly a cylindrical 
form, until they far exceed in dimensions the parent frustules, 
and at length, when mature, become, like these, transversely 
striated upon the surface. Thwaites terms these new indi- 
viduals, sporangia, comparing them probably with the 
sporangia produced by conjugation in the Desmidieae. In 
all these processes of conjugation there occurs at the same 
time an abundant secretion of a clear and gelatinous substance, 
which entirely envelopes the Diatomaceae when in the act of 
conjugation, and thus retains them in connexion. I recognize, 
however, so far a difference between this mode of propagation 
and the conjugation of most of the Desmidiea-, that in 
the conjugation of the Diatomaceae, neither a diminution 
nor increase in the number of individuals takes place ; 
only Fragilaria pectinalis offers an exception to this : in the 
conjugation of which Tliwaites saw only a single new and 
larger individual to be formed. It must at the same time 
here be noticed, that the new individuals produced in this 
remarkable way, not only exceed the parent individual 
in size, but also that they frequently exhibit a totally dif- 
ferent form, so that there is no doubt but that in time 
many of the recognized Diatomaceae will prove to be the 
so-termed sporangia of others. Thus Thwaites supposes 
that Epithemia vertagus, Kiitz., is the sporangium of Eunotia 
turgida,, Ehr. 

I*'rom all the hitherto described unicellular Algse, Pedias- 
timm differs most essentially in its interesting mode of propa- 
gation. It is known tliat the plants described by I'^hrenberg 
as Micrasterins constitute families, consisting of 4, 8, 16, 32, 
or (') 1 cells, which are disposed in the same plane, and united 
into discoid or stellate fronds. Ehrenberg, as usual, speaks 
of the polygastric apparatus, of the ovaries, and testes of these 
organisms ; all of which organs aj)pear to be hvon^hi naturally 
into harmony with those of tlie Infuscnia. With respect to 
the propagation, I'lhrenherg does not appear to have made any 
dinut ohsrrvations, for what lie describes as spontaneous 



SIEBOLD ON UNICELLULAR PLANTS AND ANIMALS. 205 

division of the single cells is, at any rate, incorrect. Two 
short remarks, made by Turpin and Meyen, on the propaga- 
tion of Pediasti'uni horganum, are dismissed by Ehrenberg 
with equal brevity, although Meyen's notice is deserving of 
much consideration. What Turpin would appear to have 
seen, with respect to the dispersion of a mass of fine spores 
from the swollen extremities of the marginal cells of the 
same species of Pediastrum, and which he even figures 
('Mem. du Museum d'Hist. Nat.,' Vol. XVI., 1828, p. 320, 
PI. XIII., fig. 22), is assuredly deceptive, because, as I am 
assured by A. Braun, the enlargements at the extremities of 
the Pediastrum in question are formed of thickened cellulose, 
and probaljly incapable of dehiscence. On the other hand, it 
appears from what Meyen says, that he had seen the remark- 
able propagation of the Pediastra. His words are as follows 
(' Nov. Act. Acad. Nat. Curios.,' Tom. XIV., Pars II., 1829, 
p. 774) : "When old, the cells gradually burst, and the aggre- 
gated mass of spores escapes endowed with a motive faculty ; 
the spores very soon come together, become loosely connected 
with one another, and, at the same time, lose the power of 
motion. The perfect individuals have no motion." That 
there is some truth in this statement I am satisfied from the 
close investigations which have been instituted by A. Braun 
on the subject of the propagation of the Pediastra. He was 
able to show me under the microscope, in Pediastrum cjranu- 
latum, Kiitz., that by segmentation of the cell-contents, 4, 8, 
16, or 32 spores are developed in the interior of each cell of 
this Alga, which spores, after the dehiscence of the cells, 
escape from them enveloped in a delicate, colourless mem- 
brane, and after moving al)out confusedly, but actively, for 
some time, arrange themselves in one plane in a stellate 
manner, after which they gradually become quiescent and 
adhere to each other. The delicate external membrane with 
which these spores are at first surrounded gradually dis- 
appears, probably being dissolved. This motion and arrange- 
ment within the delicate tunic of Pediastrum granulatum 
agrees in all respects with the highly interesting phenomena 
observed by Braun in the second form of spores of the like- 
wise unicellular Alga Hijdrodictgon 7itriculatum. In this 
case also, the very numerous spores which are produced in 
each cell exhibit, if not active moticms, yet a sort of quivering 
movement that lasts more than half an hour, until at last 
becoming applied to each other, they come to a state of rest, 
and being connected by means of the dilated mother-cell, 
arrange tliemselves into a new network, which becoming frci* 



206 SIEBOLD ON UNICELLULAR PLANTS AND ANIMALS. 

by the solution of the mother-cell, acquires the original dimen- 
sions, and after about three weeks forms new spores.* 

From this report on the more recent labours of botanists in 
the field of the lower vegetable icorld, it may be seen how 
important and indispensable the study of this branch of 
botanical knowledge must be for those who would success- 
fully apply themselves to researches connected with the lower 
animal kingdom. 

[The above paper by Von Siebold is not here given only for 
its intrinsic value, but because it has been thought that it 
would afford a pretty fair exposition of the views entertained 
at the time it was written by the more modern school of 
microscopical observers, and that it would serve as a starting- 
point from which to measure future progress in investigations 
of the nature of those to which it relates ; and that so far it 
might be useful and desirable to give it a place in an early 
number of the Microscopical Journal. It is proper, however, 
to notice that there are several points in which it will be 
seen — chiefly, however, from subsequent observation — that the 
author has fallen into error.] 



On the PsoRospERMiA and Gregarin^. Miiller's Archiv, 
1851, pp. 221. By D. F. Leydig. 

The Psorospermia are microscopical corpuscles of a peculiar 
kind, which may be generally characterized, in the full-grown 
condition, as rounded organisms, having a sharply-defined 
outline, with or without a tail-like appendage. They are 
flattened and lenticular in figure, and one pole is usually acu- 

* For further and later information (1851) on the subject not only of 
llydrodictyon, but generallj- on that of the fomiation, spores or gonidia in 
the lower Alga;, and for a most philosophical and comprehensive view of 
the whole matter, no better source can be consulted than A. Braun's 
(Betrachtungcn iil). die Erscheinung der Yerjiingimg in der Xatur. Leipzig, 
1851, pp. 364), 'Considerations on the Phenomenon of Eejuvenescence in 
Nature,' a work of which it is impossible to speak too highh% and to which 
there will be frequent occasion of reference by all who are interested in the 
important sui)j(!cts of which it treats. Kor can any one consider himself 
at all au niuedu on the subject of the propagation and development of the 
lower Alg;« who has not studied the elaborate jiaper by Cohn (Zur 
Naturgeschichte des Frotococctis phivialis, Kiitz.), ' On the Natural 
History of Protocorcm pluvinlis,' contained in the 2'_'nd vol. of the Nov. 
Act. Nat. Curios., 1850, w-hich is a complete rejiertory of all known on the 
subject up U) that i)crio(l, and moreover exhibits many new points in a 
most clear and satisfactory manner. These valuable papers are of too 
ffrcat length for insertion in this Journal, but it is intended hereafter to 
!^iv(;asuni<'.ient abstract ofeacli to place the facts and reasoning contained 
in tlicm fairly before the EngHsh ivatlcr. 



LEYDIG ON PSOROSPERMIA AND GREGARINiE. 207 

minate ; and towards this pole several internal vesicles con- 
verge in a symmetrical manner. These creatures were disco- 
vered by Joh. Miiller in 1841 (Mull. Arch., 1841, p. 477). 
He found in a young Pike minute round cysts in the cellular 
tissue of the muscles of the eye, in the substance of the scle- 
rotica, and between this and the choroid coat. The contents of 
the cysts was a whitish substance, which, when examined mi- 
croscopically, was found to consist of peculiar elements — the 
" Psorospermia." [A detailed notice of these observations is 
given in the ' Microscop. Journal,' vol. ii. p. J 23, and in the 
' Brit, and Foreign Med. Rev.,' January, 1842.] In the follow- 
ing year the same observer (Miiller's Arch., 1842, p. 193) 
discovered parasitic corpuscles in the swimming bladder of a 
Gadus callarius, which, although specifically distinct from the 
Psorospermia, approached very near the latter in their organi- 
zation. They resembled in general a smooth ventricose Navi- 
cula, and consisted of two elongated cases applied to each 
other at the cavity, and with an elliptical outline and convex 
outer surface. They were in part free, in part enclosed in 
masses within a tunic. Similar cysts, containing " Psoro- 
spermia," have been found by Leydig in several species of fish, 
and in all parts nearly of their bodies, and even in the blood 
contained in the heart (p. 2i3), and in the peritoneal cavity. 

Some facts, however, observed by him, connected with this 
subject, which came under his notice in 1850, during some 
researches on the cartilaginous fishes, served to throw a more 
general light upon these mysterious forms. 

In the gall-bladder of a Squatina angelus^ there occurred, in 
the bile, and in large quantity, peculiar forms of various 
organization, but which were manifestly developmental forms. 
1. Rounded vesicles, consisting of a delicate membrane and a 
consistent fluid. The latter was of a yellow colour and con- 
tained a multitude of also yellow granules. 2. Other vesicles 
presented, besides these, other elements of a new kind. In the 
middle of the granular contents were several perfectly trans- 
parent cellules. Small vesicles had only one oii> these cellules, 
larger ones as many as six. 3. Other parent vesicles, again, 
exhibited, besides their membrane, a granular contents and 
secondary vesicles, containing Psorospermia, always one in 
each secondary vesicle. 4. In the latter form, finally, the 
secondary vesicle had attained a large size, and the Psorosperm 
floated in a spacious clear chamber, which occupied nearly 
the whole of the parent cyst. Besides these motionless cysts, 
there were numerous free Psorospermia in the bile. 

He found, upon examination, very similar things in other 
fishes of the same class, — as in Spinax vulgaris^ Scyllium 



208 LEYDIG ON PSOROSPERMIA AND GREGARINiE. 

canicula. Torpedo narke, and Raja batis, in which the Psoro- 
spermia differed from the more usual form, in their being 
grooved or ribbed. 

It was very remarkable that the above-described organisms 
were never met with in any other part or tissue of the body 
than the gall-bladder or biliary duct. 

With respect to the nature of these bodies, Leydig is in- 
clined to think that the cyst should be regarded as belonging 
to the family of the Gregarinae, and that the " Psorospermia " 
must be looked upon as generically analogous to the " Pseudo- 
navicellae," which have been observed to be generated within 
the Gregarinae. 

The question next arises as to the existence of similar 
Gregariniform organisms producing Psorospermia, in fresh- 
water fishes. Leydig thinks there is reason to suppose that 
the animalcule discovered by Valentin in the blood of Salmo 
fario is a Gregarina. Moreover, John Miiller and Leydig 
have observed two or three ecaudate Psorospermia in Lcu- 
ciscus dobulst, enclosed in a cyst. Whence it might be sup- 
posed that secondary cells may be developed within one of 
Valentin's Haematozoa, after it has been conveyed, in the 
course of the circulation, to one organ or another ; in which 
cells Psorospermia may originate. With the growth of the 
latter the granular contents of the Gregarinae gradually dis- 
appear, which are thus transformed into cysts filled with 
Psorospermia. Such a cyst would then be equivalent to a 
Navicella-receptacle. 

The author then proceeds to discuss the vexata qucEstio 
of the true nature of the Gregarinae ; and, adverting to the 
conflicting views of Kolliker and Bruch, declares himself in 
favour of the latter, which assumes, as above stated, that the 
Greyarina is a transformed Filaria, or Anguilhda. 

In the intestine of a large species of Terehella he was en- 
abled to observe the most distinct transition between Filaria- 
like nqmatoid worms and Gregarince. The forms of the 
latter which he observed, not once only but many times, 
were — 1. A Gregarina of from 0*02"' to 0'04'" long, which 
had the form of an elongated sac, rounded at one extremity, 
and sharp at the other. The contents were those usual in 
the Gregarina*, a consistent fluid with a corpuscular sub- 
stance, wliicli (lid not occupy the pointed end, and imbedded 
in this a clear vesicle with a nucleus. 2. A Gregariniform 
creature, of a spintlle-shaped figure, closely resembling Gre- 
fjarina Terebellce, Ivoll 3. A Gregarina, generally resem- 
bling the preceding, differing only in two particulars. The 
internal substance is arranged in U)ngitudinal streaks, and 



ON THE TRANSMISSION OF INTESTINAL WORMS. 209 

the body, instead of being straight, is more or less curved 
at each end. 4. The same form, but with the body more 
elongated, vermiform ; and, for the first time, exhibiting 
motion. 5. A very pretty nematoid worm, about 10'" long ; 
blunt at one end, sharp at the other ; the contents in longi- 
tudinal stieaks, as in the two preceding forms, but with the 
spaces between them wider. Its motions are very active. 

Leydig is induced, by considerations of the above facts, and 
by other reasons, to believe that the Gregarinae are not per- 
fect animals, but " a link in the series of development of the 
Helminthes," as Henle expresses it. Another question, how- 
ever, arises : do the Gregarinae become changed into Filaria- 
form worms, or is it 1;hat the Filaria-like worms are meta- 
morphosed into Gregarinae ? Although at first inclined to 
consider the former as the time state of the case, Leydig is 
now disposed to follow Henle and Bruch, and adopt the 
latter view ; otherwise it would seem impossible to account 
for the formation of the " Pseudo navicellae " and " Psoro- 
spermia " within the Gregarinae. 



Experiments on the Transmission of Intestinal Worms. By 
M. Herbst. Annales des Sciences Naturelles, tome xvii. 
No. 1, p. 63. 

The author's experiments appear to have been directed only 
to the Trichina spiralis, or allied species. He recognizes 
three species of this genus. The first, corresponding in all 
respects with that discovered in the human body by Hilton, 
Owen, and Bischofl, was met with in the voluntary muscles of 
a large old cat. Shortly afterwards he met with a second 
species in the mesentery of Strix passerina. It occurred in 
the substance of the muscles, and also in the mesentery, in 
which situation the worm occupied yellowish tubercles about 
the size of a pin's head. This Trichina is distinguished not 
only by a body double the size of that of the other, but 
principally by the abnormal form of its extremities. The 
enlarged head terminates in a short conical point, the surface 
of which is verrucose, and the attenuated tail seems to be 
furnished with two papillary protuberances at the extremity, 
as well as with an infundibuliform opening. Tlie third 
species was met with by the author in 1848, in the muscles 
of a full-grown dog. The cysts were very small, scarcely 
visible to the naked eye. The vermiculi enclosed in them 
were much smaller, but in other respects resembled those 
of the first species, from wliich, consequently, it may be 



210 ON THE TRANSMISSION OF INTESTINAL WORMS. 

considered doubtful whether they are really specifically 
distinct. 

In November, 1850, a female Badger, about two years old, 
that the author had kept partly on vegetables and partly on 
the remains of the animals which he had dissected, died. He 
discovered the presence of an infinite number of TrichincB in 
all the voluntary muscles. This case seemed to afford a 
favourable occasion for new researches relative to the origin 
and formation of these worms. 

In 1845 the author had failed in an experiment in the 
transmission of the TrichincB. In that experiment he intro- 
duced thirty cysts containing living vermiculi between the 
skin and lumbar muscles of a young T:at. At the end of a 
month the cysts were found fixed in their situations, but the 
vermiculi were dead. On the present occasion he proceeded 
differently. The flesh of the badger was given to some young 
dogs about six weeks old, and was devoured by them in the 
course of a few days. One of the puppies was sent into the 
country, and allowed to be at large, exposed to all the external 
atmospheric influences. On the examination of the other 
two, made on the 10th and 18th of February, 1851, all the 
voluntary muscles were found to be as abundantly infested 
with the Tnckince, as were those of the badger which the 
puppies had devoured three months before. The length of 
the cysts was 133-lOOOth, their width 73-lOOOth, and the 
size of the vermicule 1166-100,000th of a line. It remained 
to ascertain the condition of the third dog, which was done 
after an interval of nine months, or in the beginning of 
November, 1851. The dog was adult, and in all respects 
vigorous and healthy in appearance. 

On the 11th of November the author exposed the sterno- 
mastoid muscle, which, to the naked eye, exhibited nothing 
extraordinary ; under the microscope, however, TrichincB 
could be recognised in such vast numbers that in a portion of 
the muscle, weighing two or three grains, as many as six 
cysts could be detected ; the length of these cvsts was 
33-lOOOth, their width 833-10,000tli, the length of the worm 
33-lOOth, and its diameter 1166-100,000th of a line. Now, 
as these worms are not common, and their appearance may 
be considered as a I'are phenomenon, there can be no doubt 
that their jiresonce in tlie three dogs in question was con- 
sequent upon tlieir having eaten the flesh of the l)adger. The 
extreme tenacity of life in these parasites, which is not appa- 
rently affected by either lieat or cold, must be considered as 
favoural)le to their propagation ; but the great difl^-ulty is 
with respect to the mode in wiiich the ova of these worms, 



KOLLIKER ON A KNOWLEDGE OF THE LOWER ANIMALS. 211 

very minute and highly elastic, it is true, but which never- 
theless present solid particles and determinate forms, reach 
the blood-vessels from the alimentary canal. For the abundant 
and simultaneous presence, as well as the uniform distribu- 
tion of these TrichincB in all the voluntary muscles, appear to 
justify the supposition that their ova are conveyed to the 
various spots in which the worms are lodged, in the course 
of the circulation of the blood. This question the author does 
not attempt to decide. 



Contributions towards a Knowledge of the Loicer Animals. By 
A. KoLLiKER. Abstracted from Siebold and Kolliker 
Zeitsch. Vol. I., p. 1. 

This paper contains a description of various species of Gre~ 
garina, with detailed observations on their structure and 
position in the animal kingdom. The following is a summary 
of the conclusions at which the author arrives : — 

1. The Gregarinap are animals. 

2. The simple Gregarinae consist indubitably of a single 
cell ; their membrane corresponds to a cell-membrane, their 
contents to a cell-contents, the vesicle to a nucleus, the granule 
or granules within it to a simple or broken-up nucleolus. 

3. The Gregarinae which are constricted at the middle also 
correspond, most probably, with a single cell of a peculiar 
kind. 

4. There is no reason whatever for supposing that the 
Gregarinae are not perfect animals. 

5. The cysts containing pseudo-Navicellae arise, in the gra- 
nular contents and vesicles, probably in a transformation of the 
Gregarinap, that is, if they are to he looked upon as younger 
Gregarinae. 

6. This being supposed, then the pseudo-Navicellae of the 
older cysts or receptacles are pi'obably to be regarded as the 
germs of the Gregarinae, which become either Gregarinae 
themselves, or, what can hardly be considered probable, ani- 
mals of another form, which, in the latter case, is to be regarded 
as the perfect form of the Gregarina. 

7. The occurrence of two nuclei or two cells in the interior 
of certain Gregarinae has either a relation to their multiplica- 
tion, or is an introduction to their transformation into pscudo- 
Navicellae-rcceptacles, 

8. The connexion of certain Gregarinae may depend upon 
a division of the pseudo-Navicellae, on the supposition that 
these are the germs of Gregarinae, or may originate in a sort 



212 KOLLIKER ON A KNOWLEDGE OF THE LOWER ANIMALS. 

of longitudinal and transverse division of the youngest Gre- 
garina. 

Thirty-five species are enumerated : to which several have 
since been added by Leidy (Proceed, of the Acad, of Nat. 
Sciences of Philadelphia, vol. iv. p. 229, or Annals Nat. Hist., 
2nd ser., vol. v. p. 317). Further observations also on the 
subject may be found by Stein in Miiller's Archiv (August, 
1849), or Annals Nat. Hist. (vol. v. p. 430) ; Henle (Jahres- 
bericht iiber Histologic, 1843, p. 49) ; C. Bruch (Sieb. and 
Koll. Zeitsch., vol. ii. p. 110), who describes minutely the 
mode in which the pseudo-Navicellae are formed, by a segmen- 
tation of the contents of a Gregarina, or of a process analogous 
to segmentation. He was unable to observe what further be- 
came of the Navicellae, which, in the Earth-worm, upon the 
Gregarinae inhabiting which Bruch's observations appear to 
have been principally made, certainly do not undergo any fur- 
ther change. He is inclined to think that the Gregarinae are 
Filariae in a quiescent state. He considers, therefore, that the 
Gregarinae afford another instance of what has been termed 
" Alternation of Generations ;" and upon the supposition that 
the Gregarina is an altered Filaria, it follows that the former 
cannot be regarded, properly, as a unicellular animal, seeing 
that the latter represents an entire vitellus, that is, an aggrega- 
tion of cells. To these observations of Bruch, or, more pro- 
perly speaking, of Henle, relative to the transformation of 
Filariae into Gregarinae, Kolliker {op. c, p. 113) replies, that 
such an alternation of generations among the Nematoid Worms 
is elsewhere unknown, regarding, with Steenstrnp and Siebold, 
that Miescher is incorrect in his observation of the transforma- 
tion of the Filariapiscium into a globular membranous envelope, 
from which, at a subsequent period, a trematoid animal, and 
finally, a Tetrarhynchus proceeds. Although the change of 
a Filaria into a Gregarina is not an impossible circumstance, 
before we admit such a thing, it is first necessary to inquire 
whether the facts stated may not be otlierwise explained. It 
is by no means proved that the Anguillula-like animal noticed 
by Henle, and termed by Bruch Filaria ; the Proteus tenax of 
Dujardin (Ann. d. S. N., 2nd ser., tom. iv. p. 354) ; the Sa- 
hlier ])roteiforrne of Suriray (Ann. d. S N., 2nd ser., tom. vi. 
p. 3jG), is really a Nematoid Worm. Kolliker is more inclined 
to regard it as an Infusorium allied to Opalina, -Proteus, &cc. 
If this be the case, there is, according to him, nothing extra- 
ordinary in its transformation into a Gregarina, and finally 
into a Navi(;ella-r(!ceptacle. He goes on to say (p. 114) that 
lie maintiiins his original opinion that the Gregarinae are per- 
l(.'ct animals, which are of the nature of simj)le cells, and pro- 



KOLLIKER ON A KNOWLEDGE OF THE LOWER ANIMALS. 213 

pagated, like many Infusoria, by germs, the so-called Navi- 
tellae. He allows, however, that there are many points in their 
economy still requiring elucidation. [With reference to Kol- 
liker's observation, that no instance of alternation of genera- 
tions is as yet known among the Nematoid Worms, we may 
notice a paper by Mr. Busk in the ' Microscopical Transac- 
tions ' for 1846, vol. ii. p. 65, PI. X. on Filaria Medinensis, 
in which the author adduces facts and reasons which induce 
him to think it not improbable that an alternation of genera 
tions may take place in the case of that Entozoon.] 



VOL. I. 



( 214 ) 



I] E V I E W S. 



Die Pflakzenzelle, der inseke Bau und das Leben der Gewachse, 
&c. (The Vegetable Cell, the Internal Structure, and Life of Plants, 
worked over in original com[:tarativ'e, microchemical researches). By 
Dr. Heumaxx Pchacht. Berlin, 1852, roy. 8vo., 672 pix, and 20 
plates with 390 figures, jiartly coloured. 

This work, for which the author has recently received a de- 
coration from the King of Prussia, was briefly alluded to in 
a former part, and we here take occasion to lay a somewhat 
extended account of it before our readers. Dr. Schacht's 
book is (me that has attracted great notice, and will have 
considerable influence on the progress of the microscopic ex- 
amination of vegetable structure, but this will not be so much 
the result of originality of tl'.e matter contained in it as of the 
method pursued in the investigations and in the exposition of 
t'iem. In fact there are few new points, and the merits of 
tlie work rest chiefly upon the industry and directness with 
which the author has worked over the whole field of vegetable 
anatomy under the point of view laid down in his title, that 
of comparison of the tissues in the various classes, not merely 
by simple inspection, but by parallel series of observations on 
development, assisted by the systematic application of re- 
agents for the determination of the chemical characters. The 
mode of operation pursued is thus described in the Introduc- 
tion (p. 7). 

" In the first place, unless I had to do with simple cellular filaments, 
as, for instance, in ('onfcrvir, I made the most perfect cross and long 
sections 1 could, and examined them in water, with a strong objective and 
a low ocular, ordinarily with nysteiu 9, and oc/dar 1 of my Oberhauser micro- 
Bco[)e ; tlici) drew all my important preparations most accurateh', and also 
fre(|uently preserved the jircjiaratiou in cliloride of calcium for subsequent 
comparison, noting at the same time everything which could not be ex- 
pressed in the drawing. Next, I treated equally perfect sections with 
solution of iodine, then with iodine and sulphuric acid; another equally 
good section was then treated witli the chloride of zinc and iodine solution, 
others with concentrated siil|iliuric acid, and others again with sugar and 
8uli)liuric acid. After 1 had carefully observed the changes which each of 
these re-agents produced on the sections, had drawn and noted them, I 
boilc<l good cross and long sections in strong solution of potash, iu a 
porcelain saucer, allowing the ley lo boil up once or twice over the sjiint- 
lanip ; then taking out the prejiaratifui an) Inyin- it in water. Watch- 
gla.sses, wliich do very wfl! f,,r maceration, are imfit for boiling prcpara- 



SCHACHTS VEGETABLE CELL. 215 

tions, as the licat increases too quickly, and they sjijit. The ]ireiiM rations, 
after being washed, were examined in water, th?n Avith the addition of 
each of the above re-agents." 

The maceration bj Schulze's process was applied to sec- 
tions and to fragments of tissue. The re-agcnts were applied 
again to the preparations, and both in those boiled, and those 
macerated, the effects were often different from those on the 
simple sections. These operations were performed on cells of 
all kinds, and in a great variety of plan's ; moreover the 
same re-agents were applied in the same way to the young 
and the perfectly developed structures of the same plant. 
With this brief notice of the nature of the experimental 
observations we pass to a summary of the most important 
contents of the book as regards micrograph ical points. 

1 he first section is devoted to a general Iitroducfion, an 
account of the method of research and a description of the 
chemical elements of the tissues. 

Sect. II. is devoted to the Essential parts of the Vef/etable 
Cell, namely, the Cell-membrane, the Protoplasm, the Nucleus, 
the Primordial Utricle, and the Cell-sap with its contents. 

In reference to the Cell-memhrane we find no new point of 
importance ; the author's observations are opposed to the 
speculations recently revived by Agardh, jun., that the primari/ 
membrane is composed of coherent fibres, and in this we are 
quite in agi'eement with him. His observations are opposed 
to Schleiden's idea, that the lenticular space between the 
contiguous " pits " of the Coniferae arises from the formation of 
an air-bubble ; he alv/ays found the space occupied by fluid. 
The details on the secondary deposits, the results of which 
confirm the views of Von Mohl in opposition to Harting and 
Mulder, will be found very instructive. — PiotojAasni is always 
to be detected by the rose-colour it takes with sugar and 
sulphuric acid (the colour sometimes does not make its 'ap- 
pearance for ten minutes). — Nucleus. T'v.e author believes that 
this body is never absent from young cells. In tliis view we 
are inclined to differ from him ; indeed the invariable detec- 
tion of nuclei in vegetable cells, by German physiologists, 
has always been a mystery to us, and whicli only seems ex- 
plicable by supposing that every roundish granule or globular 
mass of plotoplasm is a nucleus or a nucleolus. Schacht does 
not venture to affirm the existence of a membrane of the 
nucleus at auy period. — The Primordial utride is stated, in 
agreement with Mohl, Ilenfrey, Mitscherlich, »!v:c,, to be con- 
stricted (/radual/i/ in the increase of cells by division. Cell- 
sajJ and Contents. — Starch — the author agrees with S( hieiden 
in his view, that starch grains are formed by succes&ive de- 

q2 



216 SCHACHT'S VEGETABLE CELL. 

posit of layers around a nucleus. This is a very difficult 
subject, and one which is not nearly worked out yet. Chloro- 
phyll-globules are stated to be without a membranous enve- 
lope, as supposed by Nageli, Cohn, and Goppert. With 
regard to this, as also the similar membrane asserted by 
Nageli to exist around starcli, we often have seen what may 
easily be taken for such a structure, but cannot decide whether 
or not it is an optical deception. 

Sect. III. treats oi the Or it/in of the Vegetable Cell, which is 
described, in accordance with recent writers, as taking place 
in two ways, viz. : 1. Free cell-formation and 2. Parietal cell- 
formation, by division of the primordial utricle of the parent 
cell. He mentions under the latter head that the special 
parent-cells are not formed in the development of the pollen 
of Oenothera, or the spores of Authoceros lavis (to which 
might have been added those of Marchantia poh/moiyha, and 
probably otliers). In Cainbium-layers tlie cell-development 
is eftected by the division of the primordial utricle of the 
parent-cell. The paragraph on the development of the leaf 
of Sphagmim is very interesting, and the more instructive 
from the ease with wliich tlie observations may be repeated.* 
A paragraph is also devoted to the history of development of 
tlie spores of the Truftte, which accords with our own ob- 
servations. 

Sect. IV. The Growth and Nutrition of the Cell-memhrane. 
The autl'.or believes that th.e primary membrane enlarges by 
expansion, and becomes tiiinner thereby, but does not actually 
increase in substance by intussusception of molecules, as some 
have supposed The walls are thickened by secondary de- 
posits, always laminated, except in the case of spiral bands, 
in whicli no layers have yet been detected. 

Sect. V. Tlie Cells of Vegetables as connected together. In- 
tenellular substance is believed to exist, but to a much 
smaller extent than is generally imagined ; sometimes even 
not optically demonstrable. The real intercellular substance, 
as it Oit:urs sparingly in collenchynia of rinds, cScc., is coloured 
yellow by iodine. Tlie bulky deposits at the angles of 
cells, often called intercellular substance, are, in almost all 
cases, as pointed out by Vcm Mohl, stratified deposits be- 
longing to the cell -cavity, iiut rendered apparently exterior 
by changes occurring during growth. Cuticle is a subject on 
whic;h a great deal has been wriltc^n lately, not to a very de- 
cisive effect. Dr. Schacht adopts Von Mold's distinction 
between cntic/e, the thin layer, coloured yellow by iodine, 

• Tlie curious structure of the cell wall in (lie leaf of Siiliajinuni renders 
that plant an interestin;^ niicroscopic object. 



SCHACHT'S VEGETABLE CELL. 217 

found on the surface of plants, and the cuticidar lai/em on the 
inside of the outer wall of the epidermal cells, wliiih layers 
make up the greater part of the thickness of the hard epi- 
dermis. Tlie external cuticle is regarded by our author as an 
excreted product. In which conclusion he rests greatly on the 
certainly strong case of the elegantly-marked cuticle of spores 
which, like those of the Triittte, originate free in tlie cavity 
of a parent-cell. This section is very important in tlie pre- 
sent sta^je of inquiry on this head, not, indeed, as striking out 
new lisfht, but as a testimonv to facts which as yet have not 
been repeated bv many oljservers. 

Sect VI., on the khids of Ve<ietiible cdl and V^ef/efablp tisst/es, 
is, perhaps, the most interesting: in the work. Tlie structures 
are divided into free cells, viz. : — 1. The Swarming- filament 
cells {Spermatozuid cells) of the Cryptogamia ; 2. the Spor^s 
of the Cryptogamia (under which are included the Swarming- 
spores — zoospores — of the Confervae, more properly c ailed 
Gonidia); and, 3. the Pollen grain; — and Cellular tissues, 
viz. : 1. Cells and tissues of Lichens and Fungi ; 2. Cells 
and tissues of Algae ; 3. Parenchyma and its cells ; 4. Cam- 
bium and its cells ; 5. the Vessels of Plants ; 6. Wood and 
its cells ; 7. Liber-cells (containing much original observa- 
tion) ; 8. the Epidermis ; 9. the Stomates ; 10. the Appen- 
dicular organs; and, 11. Cork. Our space does not allow 
our entering into the multitude of new and interesting facts 
ascertained by our author by the application of the micro- 
chemical met!;od to these oirjects ; but his pages will repay 
attentive study. It is, perhaps, scarcely worth while to advert 
to a curious error, for which the author has been much, and 
with a narrow-minded spirit, ridiculed by VValpers, viz., the 
statement that cotton is a liber-fibre It argues certainly a 
neglect of literature, but it does not follow because tlie author 
never saw cotton in its native capsules that he does not look 
well into the plants growing round about him. The author 
denies the old statements toncerning milk-vessels, and, as in 
a separate paper published a year or two ago, declares tl at 
they are all sim])le or ramified liber-cclls, analogous to those 
long known in the Apocynaceae. 

Sect. VII. I'he Tliirkening Biny, or Cambial Ring. In 
this section the author sets up a new (UKtrine, of much im- 
portance in vegetable anatomy, if correct, namely, that tl,c 
cambium of the ring where a stem expands each yc<\\\ is <lis- 
tinct from that of the vascular bundles, and that these I'.ay 
either coincide with the former or not, which has important 
bearings in respect to explication of the growth of innny stems; 
but we are here again compelled to refer to tlie original. 



218 SCHACHT'S VEGETABLE CELL. 

Sect Vlll. comprehends the Vascvlar bniu/le.s. 
Sect. IX. Sfem, Leaf, Boot, Bud, and Fluver. This sec- 
tion contains many speculative opinions, wliicli it does not 
belongs to our office to criticise here The same may be said 
of Sect. X on the Growth of Plants, and Sect XL, the Gene- 
ral Vital Phenomena of Plants, except in regard to the para- 
graphs in the hitter, on the movements of the protoplasm 
(circulation) in cells, which are very elaborate and instructive. 
Sect. Xll. The Cell an Organ of Propagation. This 
contains a good summary of tlie facts recently made out in 
this field, examined from an original point of view. In regard 
to the Phanerogamia, our author is a firm supporter of 
Schleiden's doctrine, that the embryo originates in tlie end ot 
the pollen-tube. He obtained the prize of the Dutch Aca- 
demy on this subject a few years back, and, although almost 
the only advocate besides Scldeiden at the present time of 
this view, like that author he is exceedingly positive. We 
believe him to be wrong, from personal examination even of 
t'e cases on which he lavs greatest stress, and, considering 
the circumstances, we are not inclined to think the matter 
one longer open to question ; for we have had occasion to 
learn that Dr. Schacht met Dr. Hofmeister, one of the most 
earnest advocates tif ihe oher view, to compare preparations, 
and they parted mniualhj unconvinced', so that his preparations 
could not be quite so decisive as he asserts. It may be re- 
marked that Mr. Smith's celebrated case of Ccelohogyne ad- 
mits of a probable explanation, under the view that the em- 
bryonal vesicle originates in the embryo sac, but not under 
the hyjiothicsis that it is formed in the end of the pollen-tube. 
Sect. XII., and last, treats of the Death of the Vegetable cell. 
In an Appendix the author gives some account of tlie applica- 
tion of the polariscope to the microscope ; but here he does 
not afford any new lights; in fact the use of that instrument 
is quite new to him. A more important contribution is a 
tabular AJew ol the microscopic characters of the Coniferous 
woods. 

In conchibicm of our imperfect sketch of the chief contents 
ol this work we cannot help expiessing our admiration of Dr. 
Schacl-t's drawings, which are real drawings and not dia- 
grams ; moreover, the manner in which they are lithographed 
— printed in (olours— is a triumph of the art. It is curious 
to compare this volume with some of the dingy " sugar- 
paper" products of the German press of a dozen years ago. All 
vegetable anatomists who read (icrman ought to j)ossess this 
work; and c\(n simphj micros< opistb will lind it a mine of 
( urious and interesting siil)jects for obscr\aUon. 

AH. 



( 2iy ) 

Eeports op Juries. Exhibition of Works of Industry of \ • r. 
Nations, 1851. Class X., Section Oi^tical Instruments, Art, 'o 
Microscopes. 

Although the Reports of the Juries of the Great Exhibition 
have had a wide ciiculation, we have determined, at the 
request of several of our subscribers, to make a (ew extra* ts 
from the Report on Microscopes, which, wo tliink, will be 
interesting to the readers of our Journal. The introc^uction 
to this Report contains some interesting facts on the history 
of the construction of t!ie microscope, but to these we have 
not now space to allude. The following remarks on the 
structure of the microscope are valuable : — 

" The powers varying from l-inch to a quarter-inch focus, inclusive, 
are by far the most generally useful in the whole range of microscojn'c 
combinations, especially for educational purposes.. 

" It must be remarked that it is advisable that the angle of ar.cr- 
ture of the combiuations should not he extended to its utmost possible 
limit, when destined for the general purposes of natural history or ana- 
tomical investigation. 

" Combiuations of high jiower, and extremeh' extended angles of a]ier- 
ture, are excellent in developing one class of test objects, viz. Uiinute lines 
or dots on plane surfaces, and admirably demonstrate the high perfection 
to which such glasses are capable of lieing carried ly scientific opticians ; 
but such combinations, with a less angle of aperture and more penetrating 
power, are far more generally useful and valuable to the minute anatomist 
and the naturalist. 

" In regard to the brass-work, we may observe that the qualities espe- 
cially requisite in the stand of a microscop.e are simplicity of construction, 
portability, combined with sufficient weight to ensure safetj' and steadi- 
ness, with smoothness and accuracy of action in all the working parts, 
and such a construction as to distribute any tremor that may be com- 
municated to the instrument equally over its body, stage, and other 
working ])arts. These desirable j.oints are admirablj' attained in the form 
suggested by Mr. George Jackson, and adopted by Messrs. ^'mith and 
Ik'ck, Koss, and other makers. For purposes of delineation, Nachet's 
(France, No. 1370) form of prism is more advisable tlian that of Wollas- 
ton's, as the former, having one reflection less than the latter, presents the 
image to the eye in an erect instead of an inverted position." 

With regard to the form here said to have been suggested 
by Mr. George Jackson, we have the authority of that gentle- 
man for stating that a microscope, in whicli the body was 
attached to a saddle travelling on a bent triangular bar, was 
originally made by Mr. Ross, and figured by him in the 
article ' Microscope,' in the ' Penny Cy( lopaedia,' Mr. Ross, 
it appears, afterwards abandoned this form, when JNIr. Jackson 
again took it up, and, having obviated most of its deleits, it 
has since been adopted by Messrs. Smith and Beck and other 
makers. The following remarks on the instruments exhibited 
at the Great Exhibition will be read with interest : — 



220 REPORTS OF EXHIBITION JURIES. 

" Rof-S. — A microscope, the mechanical parts of which are exceedingly 
c;ood : the movements are very smooth and true ; the stand is on a plan 
which is solid and steady, and at the same time not cumhrous. The 
(ibjeot-glasses are constructed with different kinds of glass in the different 
compound lenses, forming a combination so as to double up the secondary 
spectrum, and this is done so well that scarcely any separation of colours 
can be detected. The angular apertures of the object-glasses examined 
are as follows : — 

1-incli focal length, 27" aperture, 
^-inch ,, (30° „ 

l-5th-inch ,, 1 13° ,, 

l-8th-inch „ 107° „ 

l-12tli-inch „ 135° 

" Both the half-inch and the one-eighth of an inch foci are puqiosely 
made of smaller proportionate aperture than the quarter-inch or the one- 
twelfth of an inch, as in all lenses of large ajierture the image becomes 
indistinct from the slightest change of focus, and so, unless an object be an 
absolute plane, it is impossible to see the whole field tolerably distinct 
at once with an object-glass of large aperture. In the set examined, the 
inch, the half-inch, and the one-eighth of an inch, are intended for the 
genej-al examination of objects ; and the one-fourth and one-twelfth of an 
inch for the examination of minute structures. 

" [Smith and Beck. — A microscope, the stand of which m appearance is 
not highly finished, but their forbearance to expend time and money on 
elaborately finishing the non-working pait has been adopted on the strong 
recommendation of some of the oldest naturalists in London, in order that 
students may acquire instruments with tirst-rate glasses at the least 
possible expense, and that such instruments may be brought within the 
compass of those whose means are limited. The stand is excellent in prin- 
cijde : the body, stage, and appliances beneath are all carried on one stout 
cast bar, on the recomnu'udation of Mr. (r. Jackson, by means of which 
the centering of the achromatic illumination is rendered easy and certain, 
and on any tremor being commimicated to the instrument, it is equally 
distributed over the whole of the working parts. 

" The lever motion to the stage of this instrument is the most easy 
and generall}' useful that has yet been applied. If used with the right 
liand, while the quick and slow adjustments to the focus are worked with 
the left, there are no animalcula? that cannot be leadily followed, however 
fitful and rapid their movements ; and any globide of blood pursuing its 
course through the most tortuous of the capillaries, can be steadih' and 
easily traced, and every alteration of its form observed during its passage 
through these minute vessels. The field of view may also be swept 
horizontally or perpendicularly, and the most delicate micrometrical 
measurements made with great ease and precision. This stage is the 
invention of Mr. Alfred White ; the rabbitted groove on which the body 
moves was suggested by Mr. (i. Jackson, at whose recommendation the 
fulcrum of the stage movement was fixed lo a sjTing, instead of to a rigid 
bar. The simplicity and efficiency of the whole of this stand is highly com- 
mendable. The object-glasses examined were of first-rate quality, and 
were as follows : — 

L2-?rd-inch focus of 28" aperture. 
4-lOlh-inch „ 70" to If" aperture. 

4-lOth-inch „ HO" a]>erture. 

l-.'^th-inch „ 1(K)" to 10;")" ai.erture. 
" 'I'hey are beautifully competed for spherical aberration, Imt the se- 
condary si>eculuni has not liccn murh diminished. The half-inch focus 



REPOKTS OF EXHIBITION JURIES. 221 

of 70" aperture is a wonderfully fine combination, easily showing objects, 
considered difficult for a one-ei,2:hth inch focal length a little more tlian a 
year since, and bearing the application of the higher eye-pieces in an un- 
precedented manner. 

" There are two tables with revolving tops, by which the microscope 
can be turned readily round for the convenience of examination by differ- 
ent observers, and thus rendered a social instrument. The microscopes 
are furnished with portable silver reflector and annular condenser, which 
exhibit transparent objects upon a dark ground. (This invention was 
made by Mr. Wenham, and tSniith and I'eck claim its first execution.) 

Varley and Son.— a microscope, the stage of which is moved by 
parallel rods, with ball and socket joints, which gives an equable motion 
in all directions, and is siiecially ada])ted for the examination of living 
objects. A second microscoi;e is exhibited, adapted for receiving vials in 
which aquatic plants or animalculai may be kept in a living state for any 
length of time. The plant is secured to one side of the vial by a piece of 
cork, and thus is within the reach of the microscope. 'J he vial is kept full 
of water, and is only corked when used, at which time it is held in a 
jacket to cut off all extraneous light ; a dark chamber projects from it 
ojjposite to the magnifier, so that a single beam of light may be made to 
fall upon the part under examination. A third microscope, of a simple 
construction, is also exhibited, chiefly intended for beginners. 

" King. — A microscope stand, with micrometers and goniometers. It 
has a pyramidal tripod, with stage traversed in rectangular planes by mi- 
crometer screws. The ])arts of this instrument are so arranged that its 
weight is equally distributed over the base, and when inclined at its 
workin;[j angle, the principal weight is below tlie ] oint of suspension, and 
the stand is steady and good. The traversing-stage is furnished with divided 
scales and verniers. The workmanshi]i throushout this instrument is of the 
first order. It is furnished with many ingenious applications of subsidiary 
instruments, and of apparatus s|)ecially adapted to the examination of 
objects by polarized light, and goniouieti-ic apparatus for measuring the 
angles of microscopic crystals. The mode of illumination, by a prism 
worked into convex spherical surfaces, is also worthy of notice. 

" Pritciiard. — An old-fashioned achromatic microsco]ie, with indifferent 
object-glasses. The working of the mechanical parts is very good. This form 
of instrument is that which led the way in the great advance that has been 
made in the micmscope by the introduction of achromatic object-glasses. 

Ladd. — A microsco];e furnished with chain and spindle moveiiients, in 
place of rack and jiinion. This movement has been ajiplied to the micro- 
scojjc m.anv years since, by Mr. Julius Vage. The motion is smooth, and 
totally free from loss of time, and is likely to stand well the eflects of 
constant use. 

" Pii.LiscHKR.^ — A large microscoi'C stand, which is good for its price, 
but unnecessarily large and inconvenient for use. 

" Jackson, E. and W. — Plain and excavated slips of glaa«, sections of 
tubes of various forms, for the construction of cells lor mounting wet 
preparations, and thin glass for covering them, of various thicknesses. 
These materials are exceedingly lusefid for scientific microscojiists. 

" Hudson.— Microscopic objects intended for the use oi^ the medical 
student, ])hysiologist, and naturalist. 

" Mk'J't. — A variety of admirably-injected microscopic objects, illns- 
tratinj; the utility of the microscope to the physiologist. 

" PouLTON.— Home well-executed microscopic objects, witli drawings to 
illustrate Iheir structure. 

" Stark. — Microscopic objects, mounted in (jKUa pvrcha cells, instead 
of (jldss ; and also slides for exhibiting opaque objects. 



222 REPORTS OF EXHIBITION JURIES. 

" Sharp. — A set of high power lenses, ten in number, for a microscope 
from one-tentli to ouc-lnmilredth of an inch focal length. 

" Shadcolt. — A sphero-anniilar condenser, for concentrating light on 
transparent objects while under microscopic examination, the object alone 
being illuminated whilst the field of \\evr is dark. 

" The princi]ile of this condenser was suggested bj^ Mr. J. F. Wenham, 
of Brixton, in his parabolic condenser. Air. Shadbolt's condenser carries 
out Mr. \\'enham's ];rinciple, with the advantage of sujerior reflecting 
arrangements, greater facilities of construction, and less liability of de- 
rangement. 

" Natchet (France). — The object-glasses, though inferior to both those 
of Eoss, and Smith and Beck, are by far the best of the foreign ones. 
They vary from a fucus of one inch to that of one*«ighleenth of an inch. 
The fuUowing were examined : that with — 

1-lSth of an inch focal length, has an aperture of 134° 
l-8th „ ^ „ 108° 

l-5th ,, „ 88° 

" In all of them the spherical aberration is not corrected ; and although 
the method of adjusting by the seiiaration of the lenses, invented by Ross, 
is adopted, yet the sj'stem is such that they are not correct at any dis- 
tance. The workmanship of the stand is very good ; an^ there arc two 
ingenious forms of microscopes exhibited. One has the object-glass below 
the stage, with the tube inclined at a convenient angle and a retlecting 
prism for the examination of chemicals, or for dissecting transi)arent ob- 
jects under fluids. The other is a dissecting microscope, with the body 
inclined in a convenient direction, and the image erected by reflecting 
])risms, so as to enable an observer to look in a convenient position whilst 
dissecting an object in fluid, which must be kept horizontal. 

" Some microscopes excellent for their price i\ ere exhibited b}' Bernard 
(France). These instruments were the cheapest in the Exhibition, though 
none were of tfie first order. 

" Chevai.iku (France). — A microscope, with indifferent object-glasses. 
The workmanship of the mechanical part, however, is \ ery good, the mode 
of mounting is excellent, and the instrument is convenient for all kinds 
of microscopic observations." 

Other instruments are referred to, but neither their excel- 
lence of workmanship nor optical power demand notice. Of 
pre])arations for the microscope, and microscopic drawings, 
there were many. Amongst the latter named in the Report, 
we may mention those of Mr. Leonard, wlio has largely 
contributed to the illustration of microscopic objects Of 
preparations, Mr. Topping exhibited an extensive series both 
of vegetable and animal structures. 

" BouRGOGNE (France) exhibited a case of microscopic objects prepared 
in tlic usual manner. They are mounted in Canada balsam, and consist 
of sections of wood, and entoniolojj;ical and other prep^arations, with a 
selection of salts to illustrate the jiolarization of light. 

•' NoiU'atr (Prussia), of Barth, has exhibited his wonderful tracings on 
glass. The ]ilan adopted by him is to trace on glass ten separate bands at 
equal distance from each other, each baud being composed of parallel 
lines of some fraction of a Prussian inch apart : in some they arc 1-loOOth, 
and in others only l-40<)Uth of a I'russian inch separated. 

" The distance of these parallel lines form parts of a geometric series; 
thus — 



BENNETT ON CLINICAL MEDICINE. 223 

0-001000 line. 

0-000857 „ 

0-000735 „ 

0-000630 „ 

0-000540 „ 

0-0004G3 ., 

000397 „ 

0-000340 „ 

0-000.-92 „ 

0-000225 „ 
" To see these lines at ali it is necessary to use a niicroscope with a 
ma;_'nifyiu'rT power of 100 diameters ; the bands containing the fewest 
number of lines will then be visible. To distintiiiish the liner lines it 
will be necessary to nse magnifying power of LOOO, and then the lines 
which are only l-47000th of an inch aj art will be seen as i)erfectly traced 
as the coarser lines. Of all the te.>ts yet found for object-glasses of high 
power these would seem to be the most valuable. 'J'hese tracings have 
t^-nded to confirm the undulating theoiy of li^ht, the ihilijrent colouis of 
the spectrum being exhibited in the ruled s; aces according to the sejara- 
tion of the lines ; and in those cases where the distaiiccs between the lines 
are smaller than the lengths of tl.e violet light wa-- es, uo colour is ]>ei-- 
ceived : and it is stated tliat if inequalities amoiuiling to '000002 line 
occur in some of the svstems, strijes of another cclour would appear in 
them." 



An Introduction to Ci tnical ^Iedicine. By John Hughks Bennett, 
M.D. Second edition. Edinburgh. Sutherland and Knox, 

To those commencing the study of the medical profession 
this little book will be found very valuable. Few of the 
manuals that have been published with the same object in 
view are so much up to the time as this little work by Dr. 
Bennett. We are induced to give it a notice in our pages, 
as out of the six lectures of which it consists two are devoted 
to the Microscope as a ineans of diagnosis. Nor do we 
think the space thus occupied disproportionate to the just 
value of this instrument in the hands of the medical practi- 
tioner. A successful treatment of disease, let practical men 
say what thej will, can only be insured by an accurate know- 
ledge of disease ; and there can be no accurate knowledge of 
diseased tissues or morbid, actions but by the aid of the 
microscope. It must not, however, be supposed that the 
microscope is an instrument easily used ; that all a man has 
to do in order to profit by its revelations is to ])urchase an 
expensive apparatus at one of our great oj)ticians. As with 
the eye itself, the practice of observation witli the microscope 
demands a careful education. Only by instruction under a 
careful teacher or a systematic course of private observation 
can any one expect to use this instrument with success. 
Whether for public courses or private study, Dr. Bennett's 
book will supply a good outline of the objects that ought to 



224 BENNETT ON CLINICAL MEDICINE. 

be examined bj a medical man. The principal physical cha- 
racters to be regarded in microscopic examinations are de- 
scribed in the following passages : — 

" 1. Shape. — Accurate observation of the shape of bodies is very neces- 
sary, as many of these are distinguished by this physical property. Thus 
the human blood ijlobules, ])resentino; a biconcave round disk, are in this 
respect different from the oval corpuscles of the camelid;v, of birds, reptiles, 
and fishes. The distinction between roiuid and globular is very necessary 
to be attended to. Human blood corpuscles are roiuid and fiat, but they 
become globular on the addition of water. Minute structures seen imder 
the microscope may also be likened to the shape of well-known objects, 
such as that of a pear, balloon, kidney, heart, etc. etc. 

" 2. Colour. — The colour of strnctures varies greatly, and often ditfers, 
under the microscope, from what was previously conceived regarding them. 
Thus the coloured corpuscles of the blood, though commonly called red, 
are, in point of fact, yellow. Many objects present different coloiirs, 
according to the mode of illumination ; that is, as the light is reflected 
from or transmitted through their substance, as in the case of certain 
scales of insects, feathers of birds, etc. Colour is often j)roduced, modified, or 
lost, b}' re-agents, as Avhen iodine comes in contact with starch corpuscles, 
when nitric acid is added to the granules of chlorophyle, or chlorine water 
affects the pigment cells of the choroid, and so on. 

" 3. Edge or Border. — The edge or border may present peculiarities 
which are worthy of notice. Thus it may be dark and abrupt on the field 
of the microscope, or so fine as to be scarcely visible. It may be smooth, 
irregular, serrated, beaded, etc. etc. 

" 4. Hize. — The size of the minute bodies, fibres, or tubes which are 
found in the various textures of animals can only be determined with ex- 
actitude hy actual measurement in the manner formerly described. It will 
be observed, for the most part, that these Uiinute structures vary in dia- 
meter, so that when their medium size cannot be determined, the varia- 
tions in size from the smaller to the larger should be stated Human 
blood-globules in a state of health have a i)retty general medium size ; and 
these ma}' consecpieutly be taken as a standard with advantage, and bodies 
may be described as being two, three, or more times larger than this 
structure. 

"5. Trdnsparency. — 'i'his physical pro] )erty varies greatly in the ulti- 
mate elements of numerous textures. Some corpuscles are quite dia- 
phanous, others are more or less opaque, 'ihe opjicity may depend upon 
corrugation or ii regularities on the external surface, or upon conten s of 
different kinds. Some bodies are so Oj.axpie as to]irevcnt the transmission 
of the rays of lieht, when they look black by transmitted lieht, although 
they be white, seen by reflected light, Others, such as fatty particles and 
oil globules, lefract the rays of light strongly, and present a peculiar 
luminous apijearance. 

*' G. Svrfiirc, — Many textures, especially lanuTiated ones, present a 
different structure on the surface from that which exists below. If, then, 
in the demonstration these have not been separated, the focal point must be 
changed by means of the fine adjustment. In this way the capillaries in 
the web of the frog's loot may bo seen to lie coveted with an epidermic 
layer, and tin; cuticle of certain minute fungi or infusoria to possess 
peculiar markings. Not unfrequently the fracture of such structures enables 
us, on examining the bnjken edge, to distinguish the difference in structure 
between the surface and the deeper layers of the tissue under examination. 

•' 7. CotilPtifs. — The contents of those structures, which consist of enve- 
lopes, as cells, or of various kinds of tubes, are very important. These may 



BENNETT ON CLINICAL MEDICINE. 225 

couisist of iucluJed cells or niiclci, granules of different kinds, pi::;n:ent 
matter, or crystals. Occasionally their contents ] resent definite moving 
curi'ents, as in the cells of some vegetables, or trembling rotatory mole- 
cular movements, as in the ordinary globules of saliva in the mouth. 

" 8. Effects of Re-ngents. — These are most imiiortant in determining 
the structure and chemical composition of numerous tissues. Indeed, in 
the same manner that the anatomi,>t with his knife separates the varioi;s 
layers of a texture he is examining, so the histologist, by the use of re- 
agents, detennines the exact natnre and composition of the minute bodies 
that fall under his inspection. 'I'hus water generally causes cell formations 
to swell out from endosmosis ; whilst syrup, gum-water, and concentrated 
saline solutions cause them to collapse from exosmosis. Acetic acid pos- 
sesses the valuable property of dissolving coagulated albumen, and, in con- 
sequence, renders the whole class of albuminous tissues more transparent. 
Thus it operates on cell walls, causing them either to dissolve or become 
so thin as to display their contents more clearly. Ether, on the other 
hand, and the alkalies, operate on the fatty compoimds, causing their solu- 
tion and disappearance. The mineral acids dissolve most of the mineral 
constituents that are met with, so that in this w^ay we are enabled to tell 
with tolerable certainty, at all events, the group of chemical compounds to 
which any particular structure may be referred." 

Short accounts are given in the book of the appearances 
of the saliva, milk, blood, pus, sputum, vomited matters, 
faeces, uterine and vaginal discharges, mucus, dropsical 
fluids, urine, and cutaneous eruptions and ulcers. In a 
manual of 130 pages, of course no detail could be expected 
on these subjects. What is given bears the stamp of being 
the result of the author's own investigations on the subjects 
he treats, and will be found all the more valuable as coming 
from one who is a good physiologist as well as a diligent 
practical physician. 



A Synopsis of the British Diatomace^. By the Rev. William Smith. 
The Plates by Tuffen West. Vol. I. London : Van Voorst. 

Amongst the organic beings whose existence the microscope 
has demonstrated, few possess a higher interest than the group 
now known as the family of Diatomaceae. Appearing every- 
where as the first-born of Life, wherever inorganic matters 
are fit for its development, these beings were looked upon sus- 
piciously by early observers, and, whilst regarded by some as 
doubtful in nature, were looked upon by others as evidences 
of spontaneous generation. Their siliceous structui'e, which 
was early known, served to give them a strange resemblance 
to the mineral world, whilst, although endowed with uioticm, 
they presented no traces of organic tissues. The labours, 
however, of Ehrenbergset at rest the question of their belong- 
ing to the mineral world, and showed how great tlieir claims 



2:?<) A SYNOPSIS OF THE BRITISH DIATOMACE.E. 

weiv ti) iK' rpfjardo'l as members of the animal kingdom. Their 
relationsliip to t'ic Desmideae was always apparent, and these 
beinj^s w-ere placed by Ehrenbers: also in tlie animal world. 
But as evidence of the vegetable nature of the Desmideae 
multiplied, so it became evident that the Diatomacea- must 
follow. The fact that both these families produce sporangia 
as the result of conjugation in common with a large number 
of the confervap, give them a common character which could 
hardly be assigned to beings belonging to both the animal 
and vegetable kingdoms. Hence Diatomacea? are now com- 
monly regarded as plants. But whilst zoologists have readily 
admitted this argument, the botanist on other grounds has 
rejected the Diatomaceae from his domain. Schleiden, in his 
' Principles of Botany,' refuses, on the ground of the compli- 
cated and unplantlike structure of Diatomaceae, to recognise 
them in the vegetable kingdom. Organisms which have thus 
constituted the battle-field of systematists must have more 
than usual interest for those who employ the instrument by 
which alone they can be discerned. But independent of this, 
there is scarcely any class of objects that present more beauti- 
ful forms, and none that invites the microscopist to a higher 
trial of the greatest powers of his instrument. On these 
accounts the present work could hardly fail to be popular 
from the subject on which it treats, and when to this is added 
the well-known reputation of the author for researches upon 
the Diatomaceae, we need hardly say that the w^ork needs no 
recommendation from ourselves. 

The present volume is illustrated with a frontispiece and 
thirfy-one plates, all of which have been drawn from nature 
and engraved by Mr. Tuffen West. As this gentleman has 
executed all the plates for the Microscopical Journal, our 
readers have at once the opportunity of forming an opinion 
of the merits of the illustrations to Mr. Smith's work. We 
have no hesitation in pronouncing them to be superior to 
anything we know that has been published on the subject. 
By far the hirger proportion of the illustrations are devoted 
to new species which have now been published for the first 
time. We may perhaps be allowed to doubt the permanence 
of many of these foims, altliough we do not the propriety of 
recording them. There is at present so great a shaking 
amongst the dry bones of species which systematists have 
recorded that we cannot but feel that some of Mr. Smith's forms 
may turn out transitionary. Not more than half the species 
are gone througli in the present volume. It includes the well- 
known genera Corconeis, (.'<it/ijn/Io(liscus, Surirelhi, Nitzsclda, 
Navicular Stauroneis, Pleui'osi(fmay Synedra, Cocconerna, and 



A SYNOPSIS OF THE BRITISH DIATOMACK.E. 227 

Gomphonema and others, whilst the larger and even more 
typical genera of Bacillaria, Meridian, Diatoma, and their 
allies, are yet to come. 

The work, in addition to the description of the species, 
with drawings of each, contains a general Introduction, in 
which the habitats, structure, functions, and the modes of col- 
lecting and preserving specimens are entered into. From the 
section on habitats we select the folloAving extract : — 

They inhabit the sea or fresh water, but tlie species pecuhar to the one 
are never found in a livinq; state in the other locahty, though there are 
some which prefer a medium of a mixed nature, and are only to be met 
\nth in water more or less brackish. The latter are often found in great 
abundance and variety in districts occasionally subject to marine influences, 
such as marshes in the neighbourhood of the sea, or the deltas of rivers, 
where, on the occurrence of high tides, the freshness of the water is 
affected by percolation from the adjoining stream, or more directly by the 
occasional overflow of its banks. Other favourite habitats of the Diato- 
maceaj are stones of mountain streams or waterfalls, and the shallow pools 
left by the retiring tide at the mouths of our larger rivers. They are not, 
however, confined to the localities I have mentioned, — they are, in fact, 
almost ubiquitous, and there is hardly a roadside ditch, water-trough, or 
cistern, which \vill not reward a search, and furnish specimens of the tribe. 

The indestructible nature of their epiderm has also served to perpetuate 
the presence of these forms in numerous localities, from which their living 
representatives have long since disappeared. Districts recovered from the 
sea, in the present or other periods of the earth's history, frequently contain 
myriads of such exuviae fonning strata of considerable thickness. Such 
deposits have been found in Bohemia, in the neighbourhood of Berlin, in 
various districts in Italy, and in several of the American States. The city 
of Eichmond in Virginia is said to be built upon a stratum of Diatomaceous 
remains 18 feet in thickness, and extensive tracts in the Arctic Regions 
h'ave been found covered with similar relics of a former vegetation. 

Nor are we without examples, though on a less extensive scale, in our 
own country. The ancient site of a mountain lake in the neighbourhood 
of Dolgelly, localities of a somewhat similar kind near Lough Island- 
Reavey, in Down, and Lough Mourne, in Antrim, have furnished large 
s applies of some of the forms described in the present work. Several 
deposits of a like kind have been met with in Scotland, and have also con- 
tributed to enrich the present volumes. The extreme minuteness of the 
organisms which have furnished such remains, and the harehiess of their 
material, have rendered the substance formed by their aggregation, a useful 
agent in the mechanical arts, in which it has been emjiloyed to confer a 
polish upon hard surfaces. It is fi"om this circumstance that the material 
known as Tri])oli derives its value as a polisher of metals ; and the Dolgelly 
deposit has to some extent been employed for a similar purpose. 

One of the most singular instances of the preservation of Diatomaceous 
forms occurs in regard to Guano, so largely imjiorted as a maiaure from 
Peru and Africa. 

Mr. Smith regards the siliceous skeleton, as it has been 
called, as perfectly homologous with the epidermal tissues of 
many vegetable organs, and the botanist will immediately 
recall to mind such instances as Deiitzia scahra, Equisetum, 



228 A SYNOPSIS OF THE BRITISH DIATOMACE^. 

and man}' of the palms and grasses in which silex enters into 
the epidermal tissues. It is true in these higher plants we 
have nothing so perfectly regular as the siliceous plates of 
Diatomaceae present, but it seems to be a law both in the 
vegetable and animal kingdoms, that the lower we descend in 
the scale of organization the more tendency do the inorganic 
constituents exhibit to submit to the inorganic law of crys- 
tallisation or symmetry of form. The following is a brief 
summary of Mr. Smith's view of the nature of the siliceous 
part of these structures : — 

The epiderm of the Diatom consists of two siliceous plates or valves, 
usually of the most perlect symmetry. When first produced, these valves 
are closely applied to each other, and the line of junction forms a suture 
along which the valves readily separate during the process of self-division 
which speedily follows the perfect formation of the cell. It seems to he a 
law with these organisms, that no portion of the internal cell-membrane 
can be exposed to the free action of the surrounding water, without secret- 
ing a siliceous epiderm ; the moment the valves become separated in the 
process of self-division, we consequently find that the secretion of a third 
plate of silex commences. This plate forms a band between the valves, 
and will for convenience sake be afterwards spoken of as the Connecting 
Membrane. As self-division is continually going on while the frusiules 
are in a healthy or growing state, it is rare to find a specimen m which 
the valves are not in some degree separated, and consequently in which 
there is not more or less of a connecting membrane. 

Mr. Smith describes " a distinct movement of the granular 
particles of the endochrome closely resembling the cell-con- 
tents in Closteriuni Lunula.''^ 

This circulation has not, however, the regularity of movement so con- 
spicuous in the Desmidieaj, and is of too ambiguous a character to furnish 
data for any very certain conclusions, save one, viz. that the Diatom must 
lie a single cell, and cannot contain a number of separate organs, such as 
have been alleged to occupy its interior ; since the endochrome moves 
freely from one ])ortion of the frustule to another, approaching and receding 
from the central nucleus unimpeded by any intervening obstacle. 

On the movements of the entire frustule Mr. Smith has no 
satisfactory theory to offer. He has never been able to dis- 
cover any semblance of a motile organ. He suggests that 
the movements may depend on endosmotic and exosmotic 
action. We must j)ass over the sections on self-division and 
classification, and give a ccmcluding extract from the direc- 
tions for collecting and preserving the Diatomacea? : — 

Let him provide himself in the first place with the necessar}- apjiaratus. 
For the field, this includes a good stock of small wide-mouthed bottles, 
that each gathering may he kept perfectly distinct ; a long rod or stick, to 
which can be attached a small muslin net ; a cutting hook, of about three 
inches in length ; and a broad flat sjioon ; the first, to collect such LJiieci- 
mens as float upon the surface, (jr are held in suspension by the water; 
the second, to remove tlus larger Alga^ which may be covered with ])arasitic 



A SYNOPSIS OF THE BRITISH DIATOMACE^E. 229 

Diatoms ; and the third, to skim the surface of the mud for those which 
lie at the bottom of the pool. 

He will probably find, notwithstanding every care, that bis specimens 
are mixed with much foreij^n matter, in the fonn of minute particles of 
mud or sand, which impair their value, and interfere with observation, 
especially with the higher powers of his instrument. These substances 
the student may remove in various ways ; bj' repeated washings in pure 
water, and at the same time, profiting by the various specific gravities of 
the Diatoms and the intermixed substances, to secure their separation ; 
but more particularly, by availing himself of the tendency vhich the 
Diatomacea% in common \\ith all growing plants, possess, of making their 
way towards the light. The free forms may be thus procured in a tolerably 
clean state ; all that is necessary being, to place the gathering which 
contains them in a shallow vessel, and leave them undisturbed for a 
sufficient length of time in the sunlight, and then carefully to remove 
them from the surface of the mud or water. 

Having performed these operations, which a little practice \y\l\ render 
comparatively easy and generally successful, the next proceeding is to 
preserve the specimens in such a manner as to render them suitable for 
examination by the microscope at any future time. This may be done in 
various ways, according to the nature of the species and the precise object 
desired. 

The simplest method, and the one most generally useful to the scientific 
observer, is simply to dry the specimens upon small portions of talc, which 
can at any time be placed imder the microscope, and examined Avithout 
further preparation ; and this mode ix)ssesses one great advantage, that 
the specimens can be submitted without fv;rther preparation to a heat 
sufficient to remove all the cell-contents and softer parts, leaving the 
siliceous epiderm in a transparent state. 

We trust Mr. Smith will not keep us waiting long for his 
second volume, and we feel that we have said enough to 
show that no one can for the future study the Diatomaceae 
without having recourse to this work, which will, we are 
assured, become a standard one on the subject. 



A History of Infusorial Animalcules living and fossil. Third 
Edition. By Andrew Pkitchard, M.R.I. London : Whittaker & Co. 

This work contains the largest amount of information on the 
subject of animalcules to be found in the English language. 
Its foundation seems to be the ' Infusionsthierchen ' of Pro- 
fessor Ehrenberg, and his classification has been adopted in 
the systematic part of the work. The author has added a 
large quantity of matter from other sources, more especially 
from the writings of English naturalists on the subject. It 
is illustrated with twenty-four plates, embracing figures of a 
very large proportion of the Infusoria after Ehrenberg, Ralfs, 
Gosse, Smith, and others. With all the attention and expense 
that have evidently been bestowed on this book one is pro- 
voked to find it so carelessly got up. The introductory 

VOL. I. R 



230 HISTORY OF INFUSORIAL ANIMALCULES. 

history contains a great quantity of very useful information, 
but it is not well arranged. Every one, however, who is 
employed in investigating the forms of animalcules will find 
here a repertory of matter to assist him in his labours. We 
are annoyed again at the perpetual misprints which, in a 
costly book with pretensions like this, are quite inexcusable. 
Who would expect to find our friend Mr. Bowerbank under 
the cacoplionious spelling of " Brawerbank "? Mr, Brown's 
remarks on molecular movements are spoken of as the xaoUe- 
cular motions of Dr. R. Browne. An order Diamomaceae is 
recognised, and Linchens is a substitute for Lichens. Cur- 
sorily glancing through the pages we have the following 
instances of mispelling : — " Monas crepuseulum," " an 
Algae," " Eyistylis," " Ampileptus," " Infusionthierchen," 
" Infusionsthierschen," and we might add many more. We 
make these remarks in no mere critical spirit, but with a 
desire that a work which is, without doubt, the most important 
one on the subject in our language, should, if it reaches 
another edition, be rendered free from these eye-sores, which 
must be annoying to every educated reader. 



( 231 ) 



NOTES AND CORRESPONDENCE. 



As many of your metropolitan readers may be glad to know 
of localities in which microscopical objects may easily be 
found, I beg leave to state for their information that the waters 
of the New River, the ornamental water in St. James's Park, 
and the fountains in Trafalgar Square, will prove well worthy 
of investigation. 

During the last two months I have obtained from the New 
River, near the City Road, Cocconeis clypeus, Cocconeis pedi- 
culus, Fragillaria ipectinalis^ Synedra valens and lunaris^ 
Closterium Leiblinii, Odontidium mesodon, Navicula Hippo- 
campus and amphirynchus^ Hydatina senta, Surirella striatula^ 
an arborescent Vorticella with 38 animalcules, Tardigrada, 
Gomphonema truncatum^ and a Vibrio, the species of which, 
from unfortunately losing the specimen, I could not de- 
termine. 

From Trafalgar Square, abundance of common Navicular, 
the Dytiscus, Lurco, Vorticella Coiivallaria and Carnpanida in 
great profusion, especially on a beautiful specimen of Clado- 
phora glomerata. 

From the Regent's Park, Amoeha (? dijffluens), Aneurea 
testudo, Gomphonema truncatum and minutissimum, Bacillaria, 
Vorticella Convallaria, Paramecium Chrysalis, and the com- 
moner Naviculae in incredible profusion. Hitherto I have only 
tried the water at the southern side, near the ferry. 

I may also mention that the small pools in fields at the 
back of the Norwood Cemetery were very rich last October in 
Volvox glohator and the variety aureus, and in Green Hydras. 
— J. M. R., Islington. 

On the Capillaries off the Iii\er. — In the last part of Todd 
and Bowman's Physiological Anatomy a doubt is expressed 
concerning the nature of tlie ultimate passages through which 
the blood circulates in the liver. Whether the smallest 
blood-vessels of this organ are true capillaries, that is, are 
possessed of a single tunic like other vessels of this descrip- 
tion, or whether the blood passes along mere spaces, or 
channels formed by the hepatic corpuscles, so as to be in 
actual contact with their cell-walls, is regarded by these 
authors as a question yet to be decided. 

Having at this time in my possession a portion of injected 

R 2 



232 



MEMORANDA. 



human liver, in which I have no difficulty in showing the 
smallest capillaries, and in demonstrating their tunic, the 
following observations will, I hope, be considered worthy of 
a place in your valuable Journal : first, because any doubt 
proceeding from such high authorities cannot fail to unsettle 
a point of minute anatomy which the microscope has satis- 
factorily established, and thereby to weaken general confidence 
in the results of all other microscopical observations ; and 
secondly, because the supposed fact of mere blood-channels 
existing in the liver whilst true capillaries are demonstrable 
in other glands seems to depart too widely from a general law 
to have even the sanction of probability in its favour. 

The examination necessary to show the capillaries of the 
liver is best made on a very thin slice of injected liver taken 
from a part bordering on that where the injection begins to 
fail, so that in the same slice there may be one part fully in- 
jected, but of course without any extravasation, another in 
which the vessels contain but little of the colouring matter of 
tlie injection, and a third, immediately continuous with this, 
in which the capillaries are empty. But, before examining 
this section, it must have been submitted to a gentle current 
of water trickling over it, in order that the biliary corpuscles 
may be entirely washed away from the meshes of those capil- 
laries which project from the thinnest part of it ; so that these 
vessels, being free in the field of view, may be seen by trans- 
mitted light, as a transparent object. 

Such is the section from which the accompanying drawing 
was taken by my friend Dr. Bristowe. 



Portion of the Liver as seen by \-8th of 
an inch lens. 

a Capillaries filled with injection. 

6 Ditto imperfectly injected. 

c Ditto containing no injection. 

rf Meshes from which tlie hepatic corpuscles 
have been entirely removed. 

e Ditto with corpuscles in them. 




In respect to their structure these capillaries differ but 
little from those of other parts : their caliljre in the liver I 



MEMORANDA. 233 

have always observed to be very unequal, arising most pro- 
bably from the manner in which they are compressed by the 
corpuscles which lie in immediate contact with their walls, 
and fill up the areolae produced by their numberless inos- 
culations. Their average diameter is about l-3000th of an 
inch. Their tunic is remarkably thin and transparent, and, 
so far as I have seen, without nuclei : but in this respect these 
vessels are not unlike the capillaries in many other parts. 
The meshes are generally circular or oval, and about 1-lOOOth 
of an inch in diameter, although some are larger and others 
smaller. 

The difficulty of displaying the capillaries of the liver I 
believe to arise from the close connexion of the hepatic cor- 
puscles with their walls (there being in this organ no visible 
basement membrane), and the extreme fragility of the latter ; 
so that the means employed to remove the corpuscles from 
the meshes of the capillaries will break away the vessels 
also. This, I think, will not be so likely to take place if the 
part have been kept a few days before examined, and be 
treated in the manner above described. 

I may observe that Mr. Busk has examined portions of this 
liver with me, and has allowed me to state that he entertains 
no doubt whatever of the existence of a wall in the capillaries 
of the liver as in other glands. — George Rainey, M.R.C.S., 
Demonstrator oj Anatomy and Microscopic Anatomy, St. 
Thomases Hospital. 

On a peculiarity in the thiciieniiig^ liayers of Vegetable 
Cells. — In the ' Botanische Zeitung ' of September 27, 1850, 
Dr. H. Schacht described a peculiar appearance he had ob- 
served in the secondary deposits of the wood-cells of Caryota 
urens, Hernandia sonora, Phwnix dactylifera, and Cocos ho- 
tryophora, consisting of slits in certain of the secondary 
layers, often taking a more or less spiral direction around 
the cell-wall. These cracks, as they may be termed, were 
often covered up again by subsequent deposits in the inside, 
so that tlicy become narrow canals, running in the thickness 
of the wall formed by secondary layers. In examining some 
cells of Hydrodictyon ntricvlatinn recently, we observed phe- 
nomena of the same kind ; and as it appears likely that some- 
thing of the same kind has given rise to J, G. Agardh's* 
idea of the cell-membrane generally being composed of fibres, 
we have thought it worth while to direct attenti(m to these 
points. These slit-like marks are well seen in portions of 
the cells of Hydrodictyon, which have been kept in chloride of 

* De ccllula vegctabili iibrillis tciiuissimis contexta. Lund., 185ii. 



234 



MEMORANDA. 



calcium, and the spiral direction of them is very evident 
towards the extremities of the cells. It is probable that a 
similar structure will be found, on more careful examination, 
on the walls of many of the Conferveae, which become much 
thickened. — Arthur Henfrey, March, 1853. 

The Finder. — Take a flat bit of wood, box, or ebony, or it 
may be ivory, half an inch longer and broader than your slides, 
and about the eighth of an inch thick. 

Along the top of this cement a bit of ivory, half an inch 
wide and as thick as the general run of your slides, and cement 
a similar bit of ivory on the left-hand end of it. 

Now, it is obvious that your slide will exactly fit upon that 
portion of the bit of wood upon which the slips of ivory are 
■not fixed. Next, in that part of the wood which is under the 
middle of the slide, cut a hole an inch long adjoining the slip 
of ivory, and three-quarters of an inch broad ; then graduate 
that part of the ivory which adjoins the hole to fiftieths of an 
inch, and thin the ivory bevel from behind adjoining the hole, 
to make the graduations transparently visible. 




To make use of the finder, place your slide in it with the 
left end of the slide close up to the shoulder at B. ; tlien hap- 
pening to observe an object — suppose a fossil Navicula, for 
instance, at a, which you wish to find again, bring it into 
the centre of your field ; then, with the vertical motion of 
your stage, move the slide down till the graduated scale comes 
into your field. Now, observe the number on the scale that 
is in the centre of the field, and mark this number on your 
slide "Naviculal 35." 

When next you want to find this Navicula, put the slide as 
before into the finder, bring the scale into your field, and 35 
on the scale into the centre of your field ; then, by the vertical 
motion of your stage yradually raise your slide till the object 
wiiich you are seeking comes into view. — John Tyrrell, 
County Court Judge of Devon, New Court. 



MEMORANDA. 235 

On the History of the Vinegar Plant. — Much was said 
and written on this plant about a year back, and we made a 
long series of observations on it, confirmatory of the opinion 
of Mr. Berkeley, that it is the mycelium of Penicillium glaucum, 
but there are many interesting points in its history which we 
cannot yet clear up. A curious fact has recently occurred to us. 
A piece of the gelatinous mass was dried and kept for some 
months, and then placed in a solution of refined sugar. After 
remaining in a dark closet about three months, through the 
winter, the solution is found still sweet, no trace of acid re- 
action being given with litmus paper. The fructification of 
the fungus is abundant, but the mass of mycelium is hlood- 
red, looking, in fact, like a mixture of half coagulated blood 
and water. This brought to mind an observation made 
some years ago, of red spots among mould upon decaying 
paste, which were found to depend on innumerable minute 
oval cells, with two granules (so-called nucleoli) in each. 
These exactly resemble detached cells of the mycelium 
(gonidia?), often occurring abundantly in the jelly of the 
Vinegar plant ; and, moreover, they are, in all probability, 
the same bodies described and figured by G. Fresenius* as a 
new species of fungus, occurring on starch jelly, under the 
name of Cryptococcus glutinis. These structures are evidently 
related to the " blood on bread " Fungus described by Ehren- 
berg, Montague, and others. — Arthur Henfrey, March, 1853. 

Mode of isolating Waviculae and other Test Objects. — 

Having found the methods ordinarily employed very tedious, 
and frequently destructive of the specimens, I adopted the 
following plan : — Select a fine hair which has been split at its 
free extremity into from 3 to 5 or 6 parts ; and having fixed 
it in a common needle-holder by passing it through a slit in a 
piece of cork, use it as a forceps under a 2-3rds of an inch 
objective, with an erecting eyepiece. When the split ex- 
tremity of the hair touches the glass slide, its parts separate 
from each other to an amount proportionate to the pressure, 
and on being brought up to the object are easily made to seize 
it, when it can be transferred as a single specimen to another 
slide without injury. The object is most easily seized when 
pushed to the edge of the fluid on the slide. 

Hairs split at the extremity may always be found in a 
shaving-brush which has been in use for some time. Tliose 
should be selected which have thin split portions so closely 
in contact that they appear single until touched at their ends. 

* F.citragc zur Mykologic, von G. Frcbcnius. Heft 11. Frankfort on 
the Maine, 1852. 



236 MEMORANDA. 

I have also found entire hairs very useful when set in needle- 
holders in a similar manner, any amount of flexibility being 
given to them by regulating the length of the part of the hair 
in use. — P. Redfern, Aberdeen. 

m^otice of a Binocular Microscope. — I devised last year, 
and have lately constructed and used, a combination of glass 
prisms, to render both eyes simultaneously serviceable in 
microscopic observation 

Behind the objective, and as near thereto as practicable, the 
light is equally divided and bent at right angles, and made to 
travel in opposite directions, by means of two rectangular 
prisms, which are in contact by their edges somewhat ground 
away. The reflected rays are received at a proper distance 
for binocular vision, upon two other rjectangular prisms, and 
again bent at right angles ; being thus either completely in- 
verted for an inverted microscope ; or restored to their first 
direction for the direct microscope. These outer prisms may- 
be cemented to the inner by Canada balsam ; or left free to 
admit of adjustment to suit different observers. Prisms of other 
form, with due arrangement, may be substituted. 

I find the metliod is applicable, with equal advantage, to 
every grade of good lens, from Spencer's best sixteenth to a 
common three-inch magnifier ; witli or without oculars or 
erecting eye-pieces ; and with a gi'eat enhancement of pene- 
trating and defining power. It gives the observer perfectly- 
correct views, in length, breadth, and depth, whatever power he 
may employ. Objects are seen holding their true relative 
positions and wearing their real shapes. A curious exception 
must be made. In viewing opaque solid bodies, with one eye- 
piece to each eye, depression appears as elevation, and eleva- 
tion as depressi(m, forming a singular illusion. For instance, 
a metal spherule appears as a glass ball silvered on tlie under 
side ; and a crystal of galena like an empty box. By the addi- 
tional use of erecting eye-pieces the images all become normal 
and natural. Match drawings of any solid object, made from 
each eye-piece, by the aid of the camera lucida, when properly 
placed in the common stereoscope, appear to stand out in 
natur.il relief. These, if engraved and printed in the proper 
position with respect to each other, might find an apj)ropriate 
place in books on the arts and sciences. 

In c(mstructing binocular eye-glasses, I use, for lightness 
and economy, four pieces of common looking-glass. Instead of 
prisms. 

With these iiisti uiuciits the microscopic dissecting knife can 
\)v cxactlv guided. Tlie natch-maker and artist can work 



MEMORANDA. 237 

under the binocular eye-jrlass with certainty and satisfaction. 
In lookinp: at microscopic animal tissues, the single eye may, 
perhaps, behold a confused amorphous or nebulous mass, 
which the pair of eyes instantly shapes into delicate super- 
imposed membranes, with intervening spaces, the thickness of 
which can be correctly estimated. Blood corpuscles, usually 
seen as flat disks, loom out as oblate spheroids. In brief, the 
whole microscopic world, as thus displayed, acquires a tenfold 
greater interest, in every phase exhibiting, in a new light, 
beauty and symmetry indescribable. J. L. Riddell. — Silli- 
mans Journal. 

On a new Slethod of illuminating Opaque Objects, fur the 
taig^li powers of the Microscope j and on a new Achromatic 
Condenser. — The front or terminal combination of the objec- 
tive is made to condense light upon the opaque object by send- 
ing rays of light from behind, through the marginal border of 
the lens. 

To accomplish this, a circular disk of fine plate glass, say 
near a fourth or fifth part as thick as the diameter of the 
lens, is bevelled on its outer margin, by grinding and polishing 
to an angle of 45 . A hole is drilled through the centre of the 
disk, of a diameter, say two-thirds, three-fourths, or four-fifths 
(dependent upon the angle of aperture), as great as that of the 
lens. The margin of this l.ole is also bevelled at an angle of 
45°, down to a clean sharp edge. Both rings of bevels are 
on the same side of the glass, so that, if considered as projected, 
the lines would cross each other at right angles. 

I find no insui'mountable difficulty in giving an exquisite 
form and finish to these disks. I mount and revolve the disk 
on a good rose lathe ; at the same time the grinding or polisli- 
ing tool is revolved by an overhead motion, the spindle caiTy- 
ing the tool being mounted upon a slide-rest, and admitting 
of a protrusive movement at an angle of 45^ to the axis of tlie 
lathe. 

The disk, being finished, is to be placed centrally behind 
the lens, the bevclhd margins looking backward, and the sharp 
inner edge almost or quite touching the lens. Parallel rays 
of light being thrown upon the disk, in the direction of the 
axis of the objective, from below in the direct, froin above in 
the inverted mi( roscope, a ring of parallel rays is sent, by two 
successive internal reflections, from ttie bevelled surfaces, so 
that, with direction reversed, the light traverses tlie outer 
margin of the objective, and by it is condensed upon the object 
in focus. 

I tested this method of illumination in March last, siiMi- 
ciently to be satisfied of its groat value ; more especially 



238 MEMORANDA. 

where the objective is of very short focal distance, and where 
consequently other means of illuminating opaque objects cannot, 
on account of the nearness of the objective to the object, be 
resorted to. 

New kind of Achromatic Condenser suggested. 

A larger, thicker, similarly bevelled disk, with the bevels 
on opposite sides of the plate glass, and their lines of inclina- 
tion coincident, would probably serve as an efficient achromatic 
condenser of parallel rays. By attaching centrally, on the side 
opposite the bevel, achromatic lenses of proper size, or a good 
doublet combination, a most valuable form of achromatic con- 
denser would I think be produced, useful for general micro- 
scopic illumination, I have not yet put the plan in practice. 
J. L. RiDDELL. — Silliman^s Journal. 



( 239 ) 



PROCEEDINGS OF SOCIETIES. 



Zoological Society. 

On the Structure of EcJiinococcus Vetermorum. By Thomas H. 
Huxley, F.R.S. 

December lAth, 1852. — The author described the structure of 
some large Echinococcus cysts with which the liver of a Zebra be- 
longing to the Zoological Society was infested. The animal met 
with its death accidentally, having always appeared to be in good 
health and condition, though the cysts were very large and nume- 
rous, occupying a great portion of the substance of the liver. 

The contents of the large cysts were free Echinococci and 
secondary Echinococcus cysts, contained in a clear fluid. The 
former were alive, and exhibited distinct, contractile motions. 
Attention was drawn to two important points in their structure, 
firstly, that the well known oval corpuscles were not calcareous, 
inasmuch as they were rapidly dissolved by acetic acid without effer- 
vescence, and were considerably acted upon by strong ammonia. 
The author supposed that they were albuminous, and that, both in 
these and tlie Taeniae, the conversion into calcareous substance is 
an effect of degradation ; and he pointed out their relations with 
the solid bodies in the integument of the Turbellaria, and with the 
so-called thread-cells of these and the Polypes. Secondly, that the 
peculiar wavy cilia, characteristic of a water vascular system, could 
be seen in motioti in the living Echinococci. The cilia were de- 
scribed by Lebert in 1843, but the discovery seems to have been 
forgotten ; it is, however, a point of great importance now that the 
existence of similar cilia in a definite water vascular system has 
been demonstrated in the other Cestoid worms. 

The proper wall of the cyst (as distinguished from the laminated 
capsule) was traversed by a network of anastomosing vessels, to the 
points of union of which the fixed Echinococci were attached, the 
cavity of the pedicle of the latter appearing to be continuous with 
that of the vessels. It is in the cavity of the pedicle that Virchow 
observed cilia. The secondary cysts varied in size from 1 -100th to 
l-30th of an inch. The contained Echinococci were always of 
about the same size, and all the smaller secondary cysts possessed 
from one to four Echinococcus heads attached to their outer sur- 
face. The wall of the secondary cysts contains vessels like those of 
the primary one. In the larger cysts the external heads were 
found gradually disappearing, until they were quite smooth exter- 
nally. When the secondary cysts were burst, their membrane con- 
tinued to connect tiie heads, and formed the pedicle described by 
various authors. The formation of the secondary cysts takes place 
thus : — Echinococcus heads are formed over the whole inner surface 



240 PROCEEDINGS OF SOCIETIES. 

of the cyst ; this then becomes raised up at one spot by the develop- 
ment of Echinococcus heads, outside it also, and, gradually project- 
ing inwards, and acquiring a narrower and narrower pedicle, it 
eventually falls into the cavity of the cyst as a free secondary cyst. 
The external heads of the secondary cyst (internal of the primary 
cyst) then gradually disappear ; the internal ones (external of the 
primary cyst) remaining entire and in a normal state. The process 
is not essentially different from the ordinary germination of a TcEiiia 
or Cysticercus. 

The author then endeavoured to show that the Echinococcus 
is nothing but the " Scnlex-fonn" to use Van Beneden's term, of 
a T(B7iia, retracted within itself, then greatly dilated and deve- 
loping Echinococcus heads from its inner and outer surfaces, which 
are, however, like those df a serous sac, in reality both outer. It is 
the extreme result of modifications similar to those already under- 
gone by the Tanioid type in Camirus and Cysticercus. The 
conclusion thus drawn on anatomical grounds is strikingly confirmed 
by the result of the recent experiments of Von Siebold, who fed 
young puppies with milk containing Echinococci, and, after a short 
time, discovered TanicB in their intestines. 

The author then, in speaking of tiie literature of the subject, 
showed that the true nature of the Echinococci was fully under- 
stood by CToeze in 1782. 

The paper was illustrated by nmnerous drawings. 



Royal Society. 



Thursday, March 17, 1853. — Two papers by Dr. Martin Barry 
were read ; one on the subject of tiie ultimate structure of the mus- 
cular fibre, and of other tissues in animals and plants. The second 
on the occurrence of spermatozoa in the interior of the mammalian 
ovum. Dr. Barry's mode of viewing tliese subjects, but particu- 
larly, perhaps, the former, is doubtless well known to all our 
readers who may be interested in them, and neither paper presented 
anything at all novel or interesting, as they were, in fact, merely 
repetitions of the views first broached by Dr. Barry ten or eleven 
years ago ; and an attempted vindication of them against the 
combined opinions of nearly all observers since that time. With 
respect to the former of these subjects, the only modification the 
author's views have lately undergone consists in this, — that whereas 
forn)erly the mystical double spirals perversely twisted themselves 
in opposite directions, they are now harmoniously contorted in the 
same. 

Had it not therefore been partly from the circumstance of these 
papers being read at the Royal Society, whence they might be snp- 
jjosed to derive s(mie extrinsic claim to attention, we should hardly 
liave thought it worth while further to advert to them, or rather to 
the former of them, — but on this account, and also because Dr. 



PROCEEDINGS OF SOCIETIES. 241 

Barry's views have not long since been again produced under the 
respectable auspices of Purkinje, and in the pages of Miiller's 
Archiv. on tlie Continent, and in one of our most scientific 
periodicals in this country, — we have thought it right to say a few 
words on the matter. It is needless to enter into any discussion 
with respect to the supposed facts adduced by Dr. Barry — for the 
question, as one of fact, really admits of no discussion, and with 
respect to the worth of the speculations, founded upon these facts, it 
may suffice to observe that when Dr. Barry's views regarding fibre, 
contained in Iiis paper in the Philosophical Transactions for 1842, 
were first promulgated, they met with the most direct contradiction 
from nearly every competent microscopic observer — at that time, 
however, not a numerous class, and that, in the interval which has 
since elapsed — and the ten years have produced a host of most com- 
petent histologists — they have found no support, or scarcely any, 
from any independent quarter, but, on the contrary, have almost 
invariably, when noticed at all, been described as " mythical and 
fantastical." The conversion or rather perversion of the venerable 
Purkinje to these views seems to have taken place under the direct 
inspiration of Dr. Barry himself, and probably from examination of 
iiis preparations. Dr. Barry, it is true, also claims the support of 
Professor Agardh, given in his work on the structure of the cell- 
wall in certain Algae; but it would be easy to show that Agardh's 
spiral structure, which moreover really relates only to the secondary 
deposits in the wall, has little or no connexion with the mythical 
double spirals of Dr. M. Barry. And we fancy that Professor 
Agardh would hardly deem it a compliment were he supposed to 
entertain the notion that the nucleus of a cell " resembles a ball of 
twine, which it gives off to weave the cell-wall !" — With reference 
to which we should be curious to see Dr. Barry's explanation of the 
formation of the cellulose wall around the primordial utricle in 
Hydrodictyon, for instance, when no nucleus, in the common accep- 
tation of the term, exists at any time, — that is, no nucleus distin- 
guishable from the rest of the primordial utricle. 

In his paper Dr. Barry also quotes Dr. Allen Thompson as a 
believer in his views with respect to muscle. We have no infor- 
mation on the subject, but perhaps Dr. Allen Thompson may have 
since seen reason to doubt part at least of the premises upon which 
he was led to fall into Dr. Barry's views. His very high and 
deserved authority in questions of this kind would, at all events, 
render the knowledge of his present opinions most satisfactory. 

With respect to the second paper, wliich consisted chiefly of a 
reclamation of Dr. Barry's priority in the discovery of the entry of 
the spermatozoa into the ovum, elicited apparently by some expres- 
sions in Dr. Nelson's most valuable paper on Ascaris mystax it 
is unnecessary here to say anything. 



242 PROCEEDINGS OF SOCIETIES. 

Microscopical Society. 

George Jackson, Esq., President, in the Chair. 

March 23, 1853.— A paper, by Dr. William Gregory, F.R.S.E., 
Professor of Chemistry in the University of Edinburgh, entitled 
' Notice of a Diatomaceous Earth found in the Island of Mull,' was 
read. The author commenced by stating that this earth was disco- 
vered about two years ago by the Duke of Argyle, who gave a short 
account of its geological position to the Royal Society of Edinburgh. 
It constitutes a bed resembling marl in appearance, lying in a rough 
piece of ground at Knock near Aros, between Loch Baa, a fresh- 
water lake, and the sea. It is extremely rich in Diatomaceous 
remains, containing (according to a synopsis sent with the paper) 
various sjiecies of the genera Pinnnlaria Navicula, Gomphonema 
Amphora Stauroneis, Cocconeis, Surirella Cymbella Himantidium, 
Tabellaria Epithemia, Eunotia Cymatopleura, Synedra Fragilaria 
and Orthosira. Those most remarkable for their abundance are the 
genera Pinnularia Navicula and Stauroneis, and many of the species 
of these and of the other genera are of great rarity. After giving 
the chemical analysis, the Professor concluded by stating that the 
Mull deposit appears to him to be richer in Diatomaceous species, 
and perhaps in genera, than any other known deposit, there being 
at least 60 species and 16 genera enumerated as having been found 
in it. A portion of the earth and some slides containing specimens 
accompany the paper. 



( 243 ) 



OBITUARY. 



It is with the deepest feelings of regret we have to record the 
unexpected death of Dr. Jonathan Pereira, F.R.S., F.L.S., &c., at 
the age of 49, whilst in the prime of life and mental vigour. A 
few weeks previous to this occurrence, he had been to consult Pro- 
fessor Quekett on a scientific question ; and whilst descending a 
staircase leading to the Hunterian Museum, made a false step, fell, 
and ruptured the rectus femoris muscle of both legs. In all pro- 
bability, at the same time, some internal injury was sustained by the 
heart or larger vessels, but as only local inconvenience was experi- 
enced no danger was apprehended ; but whilst getting into bed on 
the 20th of January, he felt a violent throb in the region of the 
heart, when he became fully aware that a speedy termination to his 
life was at hand, and this impression was verified within twenty 
minutes after. He was a man of portly bearing, with pleasing 
expression of countenance and great frankness of manner. Few 
men were possessed of such general and sound knowledge of subjects 
connected with his profession, and wdth so little affectation. He 
was an excellent observer in pharmaceutical microscopy and 
chemistry, and had a keen eye for what was practical ; his literary 
judgment was very sound. He was author of ' Elements of Materia 
Medica and Therapeutics,' a work of universal reputation ; the con- 
cluding portion of the third edition he was actively engaged on up 
to the time of his death. He also wrote ' A Treatise on Food and 
Diet ;' ' Selecta e Prescriptis ;' and ' Lectures on Polarised Light,' 
the best familiar exposition of that abstruse subject in our language. 
He also contributed numerous articles to societies, journals, reviews, 
&c. By his labours he rescued therapeutics from the chaos of 
hypothesis and absurdity in which it was formerly involved, and 
established it on a firm scientific basis. His death has left a void 
amongst European pharmaceutists which will not be readily filled. 
As a lecturer, he secured the attention of his class by an earnestness 
of purpose, aptness of experimental illustration, and the practical 
bearing of his remarks. He was a real friend to the student, to 
whom he was ever most liberal in affording assistance, often devoting 
valuable time in making him thoroughly acquainted with the subject 
of his studies. Dr. Pereira was, at the commencement of his 
medical career, apprenticed to a general practitioner, attended the 
Aldersgate Dispensary, became its apothecary, and lectured on 
Chemistry and Materia Medica. He afterwards became lecturer 
on these subjects at the Aldersgate School of Medicine, where his 
lectures attracted many students from the City hospitals. He 
subsequently lectured at the London Hospital, till about six years 
since. In 1840 he obtained the degree of M.D. Erlangen, and 



244 OBITUAllY. 

became a liccntiatf^ of tlie London College of Physicians, and was 
elected a fellow of that body in 1845. In 1841 he was appointed 
Physician to the London Hospital, which post he occupied up to the 
time of lii-< death. He also lectured at tlie Pharmaceutical Society, 
and was Examiner on Materia Medica in the University of London. 
Though of good and affluent family, from reverses suffered by his 
father through unfortunate mercantile speculations he was obliged 
to make his way through the world unassisted, and he attained his 
high position in the profession entirely through his own industry 
and perseverance. He was a liberal advocate of popular education, 
and frequently lent his aid at our scientific institutions. He loved 
science for its own sake, and his name will ever be associated with 
those departments to which he devoted his labours ; whilst those 
who were personally acquainted with him will long honour his 
memory. 



DESCRIPTION OF PLATE III. 

The letters refer tlirou;^boiit to the same or correspoiidiny parts. 
a. The INIucous Membrane of the mouth. 
h. The Lip. 

c. The Alveolus. 

d. The Pulp. 

e. The Dentine. 
/. The Enamel. 

(J. The Basement INIembrane of the Pulp. 

<l '. Nasmyth's Membrane especially. 

h. The " Enamel-organ " or Epithelium of the Capsule. 

i. The Basement Membrane of the Capsule, with its subjacent con- 
densed tunic. Hunter's inner, vascirlar, capsule. 

k. The loose submucous cellular Tunic. Hunter's outer, non-vascular, 
capsule. 

Fig. 1. Diagi'ammatic section of the inner incisor of the upjier jaw 
of a Seven-months Foetus. The loose enamel organ is indicated by * * * *. 

Fig. 2. A cusp of the posterior molar, upper jaw of the same. The inner 
outline represents it before the addition of acetic acid — the outer after- 
wards, when Nasmyth's membrane is seen raised up into large folds. 

Fig. 3. Edge of an incisor pulp — retaining its cap — not far from the 
lower edge of the dentine, which was about 1-lGOOth of an inch thick. 

Fig. 4. Edge of the pulp of a molar cusp, showing the first rudiment of 
the dentine, commencing in a perfectly transparent layer between the 
" nuclei " of the pulp and the membrana preformativa. 

Fig. 5. Surface of tins dentine, where it had attained a thickness of 
l-2500th of an inch, before which the little cavities, if present, were not 
visible. 

Fig. 6. Nasmyth's membrane detached from the subjacent enamel by 
acetic acid. 

Fig. 7. The " stellate-cells " of the human " enamel-organ." 

Fig. 8. Tooth of the Frog, acted on by dilute hydrochloric acid, so as to 
dissolve the enamel and free Nasmyth's membrane. The structure of the 
dentine is rendered indistinct. At the base Nasmyth's membrane is con- 
tinued over the bony substance at z, in which the nuclei of the lacunae 
are visible. 

Fig. 9. Extremity of the tooth of a Mackarel, acted on by hydrochloric 
acid so as to dissolve tlie enamel. Nasmyth's membrane is rendered 
obvious, but is burst on the left-hand edge. 

Fig. 10. Tooth-sac of a Mackarel, l-oOth of an inch long, extracted 
from its alveolus. Its close resemblance to a hair-sac is very striking. 

Fig. 11. Diagrammatic section of the dental follicles of a Skate, to show 
the union of the upper and lower folds of the " dental groove." 

Fig. 12. Extremity of a dermic, tooth-like spine, from the upper 
surface of the head in tlie Skate, acted on by hydrochloric acid, which has 
removed the layer of enamel. 



VOL. I. 



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DESCRIPTION OF PLATE VII. 

These Positive Photographs from Collodion Negatives, taken by 
J. Delves, Esq., illustrate that gentleman's, Mr. Shadbolt's, and Mr. 
S. Highley's papers on Photography. 

Fig. 

1. Spiracle and Trachefe of the Silkworm, magnified 60 diameters, exhi- 

biting the elastic spiral fibre between the layers of the air vessels. 

2. Proboscis of the Fly, magnified 180 diameters, showing the divided 

absorbent tubes. 



DESCRIPTION OF PLATE VIII. 

0)1 the Starch-grannie, hy G.^Biisk, Esq. 
Fig. 

1, 2, 3, 4, 5. Various forms of starch-2;rannles in " Tons les mois " 
Arrowroot. 

6. Grannies beginning to expand. 

7, 8, 9. Farther progressive stages of expansion of the grannie of " Tons 

les mois." 

10. Varions forms of starch obtained from the Horse-chestnut {jEscuIus 

h ippocastanuni). 

11, 12, 13. Granules of the same starch acted upon bj' sulphuric acid. 



DESCRIPTION OF PLATE IX. 

On Asteridia in Conferva?, hy the Rev. W. Smith. 

1. Filament oi Zy(jnema riuininum, Ag., containing Asteridia. in various 
stages of development. 

2.1 Filaments of Mesocarpus scalaris, Hass., var. /8, in coniugation, and 

3. 1 containing Asteridia. 

4. Filament of Zygnema quadrntum, Hass., in conjugntion. 

.'). Filanient of the same containing an Asteridimn, and another a repro- 
ductive spore. 

i). Filament of the same, showing a double mode of conjugation in the 
same species. 



On a Fungus in an Oak Tree, by Prof. E. J. Quekett. 

7. A [)ortion of an oak tree, showing a fungus and masses of crystals, 

in situ. 

8. Fungus magnified 150 diameters. 

9. I.arge crystal, having fungi in its interior. 
10. A portion of fungus seen within a crystal. 



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( 245 ) 



ORIGINAL COMMUNICATIONS. 



On the genus Triceratmm^ xcith Descriptions and Figures of the 
Species. By T. Brightwell, F.L.S. 

The genus Triceratium, with several other genera of Diato- 
maceae, was established by Ehrenberg in a Memoir com- 
municated by him to the Berlin Academy in 1839-1840.* 
He founded it upon two species, described and figured in 
the Memoir, T. favus nnd T. striolatum, the former of which 
is commonly taken as the type of the genus. 

Several new species were afterwards described by Ehren- 
berg in the monthly reports of the Berlin Academy, most, or 
all of which, are given in Pritchard's ' History of Infusorial 
Animalcules,' ed. 1852, pp. 448, 449, and in Kutzing's 
' Species Algarum,' 1849, pp. 140, 141, but no figures have 
been given of these species. Professor Bailey, of New York, 
has described and figured one or two species discovered by 
him. 

We purpose, in the present memoir, to give descriptions 
and figures of the known species, and to add some others 
which have hitherto been unnoticed. 

The Triceratia are all marine. We have detected nearly 
all the recent species described in this memoir in material 
obtained from the surface of the large sea-shells of the genera 
Hippopus and Haliotis, before they have been cleaned. Many 
of them, in this state, are covered with small zoophytes, 
minute algae, and other parasites, and by a careful examina- 
tion of these, Triceratia and other Diatomaceae have been 
obtained. 

I have been indebted for a supply of one new and in- 
teresting species, collected by Dr. Sutherland in the Arctic 
Regions, to Dr. Baird of the British Museum. It is noticed 
as ' T. striolatum., Ehr ,' in the appendix to Dr. Sutherland's 
' Journal of his Voyage in Baffin's Bay and Barrow's Straits,' 
1850-1851, vol. ii. pp. cxcv-cxcix. ' Diatomaceae.' Having, 
by the means above mentioned, obtained a good supply of 
T. striolatum, and finding it to be clearly distinct from the 
arctic one, I have named the latter T. arcticum. Dr. Suther- 

* Uber nocli jctzt zahh-cich lebeude Thiera'rten der Krcidebildiiiii; und 
den Orgauismiis dor Polythalamicii. Von Ii'"" Khrcnberg. Abhandhuigen 
der Kciniglichen Akadeniie der Wisscnschaften zu BerHn, 183U, p. 81. 

VOL. I. S 



246 ON THE GENUS TRICERATIUM. 

land has given the following note with this species — " Taken 
from a depth of fifteen fathoms, shingly bottom, calcareous 
district. Temperature of the water 31°.8 ; covered with 
ice for nine months of every 3-ear. Union Bay, Beechey 
Island, lat. 74° 43' ; long. 92° VV. September 4th, 1850." 

The frustules of this species were found in a mass un- 
mixed with any other Diatomaceae, and very much broken. 
Many of the perfect frustules have the endochrome in them, 
and when examined as first received, had very much the 
appearance of being attached to a minute alga found among 
them. This is, I believe, the only instance in which a large 
number of living frustules of Triceratia have been found 
isolated, and almost compacted together. Among the Dia- 
tomacecB collected by Dr. Sutherland in other parts of the 
Arctic Seas, I have found a few frustules of T. arcticum, but 
these occur, as do most of the other species, sparingly. 1 
have not been able to detect among all the specimens of 
T. arcticum, furnished me, a single one, in which the fissi- 
parous division appears to have commenced ; all the speci- 
mens are, however, nearly equal in size, and agree in form 
and structure, not presenting any of the variations which I 
have noticed in T. striolatum, and in one other species as 
hereafter mentioned. 

Ehrenberg has given elaborate figures of the end and front 
view of T. striolatum, in the memoir above mentioned, but 
he has not noticed any varieties of this, or, I believe, any 
other species. 

The general form of T. striolatum, on an end view, is 
triangular, but I have found among the frustules obtained, 
from the shells above mentioned, several specimens of a 
pentagonal form, and having the appearance of being com- 
posed of a number of pentagonal plates united together. 
The colour and sculpture of these five-sided frustules is 
precisely the same as that of the triangular ones, I have 
also detected another variety of a cubical form, presenting 
nearly a perfect square on the end view, and agreeing in 
colour and sculpture with the triangular specimens. I have 
not met with variations of this kind in any other species 
except in T. scituhnn, mihi, a small species in Avhich the sur- 
face is marked with large hexagonal cells, and in this species 
I have detected a variety with four concave sides on an end 
view, of which I have given a figure. Among the specimens 
of T. favus, obtained from Thames mud, I have found one 
presenting a very remarkable singularity. A semi-circular 
arch is hollowed out of the centre of the end walls, having 
a regular arched rim of square cells around it, resembling the 



ON THE GENUS TRICEEATIUM. 247 

key-stones of a bridge, and leading to the conclusion that the 
frustule, in its formation, meeting with some impediment, 
had formed its walls around it. 

These variations in form appear to me to confirm the view 
now generally taken of the vegetable character of the Diato- 
macecB^ while, on the other hand, they are in opposition to 
the general law regulating the multiplication of the species. 
Such forms could not proceed from a spontaneous longi- 
tudinal division, in which each half produced a counterpart 
of itself. They are perhaps the result of that specific mode 
of reproduction to which Mr. Smith has alluded in his 
valuable papers on the Diatomaceae, in the ' Annals of 
Natural History ' (series 2nd, vol. ix. p. 5), In this mode 
of reproduction it is quite possible that abnormal variations 
of form may take place. 

For some excellent observations on the structure, mode of 
growth, and general physiology of the Diatomaceae, I beg to 
refer the reader to the above-mentioned paper by Mr. Smith, 
and particularly to that contained in the ' Annals,' series 2nd, 
vol. vii. pp. 1-5, and also to his Introduction to his most 
useful ' Synopsis of the British Diatomaceae,' the first volume 
of which has been recently published. 

Nearly one-half of the described species of Diatomaceae 
are fossil, the greater number being found in the Bermudas. 
Several of the fossil forms are also found among the living 
species. One of the difficulties attending the study of this 
genus, and the determination, especially in the fossil forms, 
of the species, arises from the difficulty of obtaining perfect 
frustules, and examining them in their front aspect. The 
imperfect frustules present only the end or triangular wall, 
from which alone no perfectly satisfactory specific character 
can be obtained. For this reason several of the species here 
described and figured must be adopted only provisionally, i. e. 
till perfect frustules can be examined. 

Many of the species also vary extremely in size. I have 
observed this to be the case with nearly all the species of 
which I have had an opportunity of obtaining many speci- 
mens. In T. striolatum and T. alternans, and in the latter 
both in the recent and fossil specimens, the variations in 
size are such as force one to the conclusion that they have 
been formed by conjugation of frustules, or some mode of 
reproduction varying from that of self-division. In the out- 
line figures of varieties of T. striolatum (PI. IV., fig. 11), 
will be found two, in which small frustules are adhering to 
larger ones, as if they were budding or growing from them ; 
this whole group were gathered from a shell of Ilippopus 

s 2 



248 ON THE GENUS TRICERATIUM. 

maculatus, and are figured as they appeared, lying in a watch- 
glass, with a little water over them. 

The species of the genus Triceratium may, for the most part, 
be recognised bv the triangular form they present, on an end 
view of the frustules. The normal form of the frustule inay be 
represented by a vertical section of a triangular prism. If the 
frustule be placed upon one of its flat sides, we look down 
upon its ridge and obtain a front view of its two other sloping 
sides. If it be placed upon one of its ridges, we have a front 
view of one of its flat sides, generally broader than long, and 
of its smooth or transparent suture, or connecting inembrane. 
If the frustule be progressing towards self-division, it is then 
often considerably longer than broad, and when nearly matured 
for separation, presents the appearance of a double frustule. 

A simple frustule, when dissected or broken up, consists of 
two triangular plates or walls of silex, forming the ends, and 
of three oblong rectangular pieces or bands, forming the three 
sides ; the latter usually dividing themselves into several 
elongated paralleliform pieces. These siliceous plates them- 
selves are formed of several distinct layers of slles, dividing, 
like the thin divisions of talc, and are frequently found of such 
exquisite delicacy as to be difficult of detection. 
Synopsis of the Species. 

Section I. — Sides concave ivith the angles protruded. Valvular 
cells minute. 

1. T. Solennoceros, Ehr. Sides deeply concave. Angles ex- 
tended into long arms rounded off at the ends. Cells radiating in 
straight lines to the extremity of the arms. Diam. 1 -276th. 

Fossil, in Bermuda earth. Perfect specimens of this singular and 
beautiful species are rarely found. Ehr. describes the arms as 
tubular. 

Kutzing, Species Algarum, p. 140. 

Plate IV., fig. 1. 

2. T. hrachiolatum, raihi. Sides concave. The angles extended 
into short arms, rounded at the ends, which are perfectly smooth, 
while the rest of the valve is covered with minute cells. Diam. 
l-250th. 

New Zealand. Recent ; from the cleanings of shells and small 
algae. Rare. 

Plate IV., fig. 2. 

N.B. — This species appears allied to T. pileolus, Ehr. ; but is 
much larger, and probably distinct. 

3. T. tridactyluin, nuiii. Sides concave. Angles carried out 
into a distinct papilliform extremity. Surface of the valves covered 
with minute cells. Diam. 1-3 18th. 

Fossil, in Petersburg earth, N. A. Rare. 
Plate IV., fig. 3. 



ON THE GENUS TRICERATIUM. 249 

Section II. — Sides strniyht, or somewhat convex, 
a, Surface with large hexagonal cells. 
* Angles spinose. 

4. T. comtnm, Ehr. Sides straight. Angles extended into a 
short stout spine. Sides of the angles with a projecting fringe, the 
fringe having a row of oval depressions. Surface covered with 
large hexagonal cells. The edge of the fringe is sometimes broken 
off, leaving the appearance of small spines. Diam. l-218th. 

Kutzing, S. A., p. 140. 

From the cleanings of Tridacnidae and other shells. 

Plate IV., fig. 4. 

5. T. muricattan, mihi. A minute species. Sides straight. 
Angles ending in a stout spine. Front view nearly square, re- 
sembling an Odontella or Zygoceros. Diam. l-583rd. 

From the cleanings of Tridacnidae and otiier shells. 
Plate IV., fig. 5, a, a, front view ; b, end view. 

6. T. spinosum, Bailey. Sides furnished with 4 lateral setae. 
Kutzing, S. A.., p. 141. 

In North America; a doubtful species. No figure has been 
given of it, and I have not seen a specimen. 

* * Angles not spinose. 

7. T.favus,'EMv. Angles having an obtuse projection. Cells 
on the surface large, and the hexagonal figure of them well defined. 

Kutzing, S. A., p. 140. Diam. l-200th to l-150th. 

Smith's 'Brit. Diatomacese,' vol. i., p. 26; plate v. 44, end 
view ; and supp., plate xxx. 44, front view. 

Thames mud, at the junction of the Yare and Waveney, near 
Yarmouth. This species appears pretty generally distributed. 
I have found it on shells, from various regions, and fossil in 
Petersburg earth, N. A. 

Plate IV., fig. 6. This figure presents the remarkable formation 
noticed before. 

8. T. megastonmm, Ehr. Sides straight. The hexangular cells 
smaller and more delicate than in T. favus. Diam. l-350th to 
l-17oth. 

Kutzing, S. A., p. 140. 

Allied to T. favus ; but distinguished from it by its smaller size, 
more delicate structure, and sharp triangidar form. 

Found in Ichaboe and other guano, and among the cleanings 
and small algae fioni foreign shells, varying much in size. 

Plate IV., fig. 7. 

9. T. grande, mihi. The largest and stoutest species of this 
genus. Sides convex. Angles atteimated, obtuse. Hexagonal 
cells numerous. 

Found on Tridacnidae and other shells from the Indian Seas, not 
unfrequent. Diam. 1 -100th. 
Plate IV., fig. 8. 



250 ON THE GENUS TRICERATIUM, 

Ehrenberg has described a large species ( T. ocellatuni) from the 
Indian Seas. See Kutzing, S. A., I4l ; but his description differs 
altogether from the present one. 

10. T. scitulum, mihi. A small species, but varying in size ; on 
some of the frustules I have reckoned on an end view, about 45 
cells only ; very slightly convex on the sides. Angles open. Diam. 
l-3oOth. 

From the cleanings of shells from the Indian Ocean. 
Plate IV., fig. 9 ; a, end view. 

Var. y8. Having four concave sides. I have detected this 
curious variety on several occasions. 

b. Cells very small. 

11. T. striolatum, Ehr. Frustule on a front view longer than 
broad with the ends deeply concave, transparent ; colour, pale 
brown. The whole, under a high magnifying power, delicately 
marked with minute cells. Diam. l-290th. 

Kutzing, S. A., p. 140. 

Var. ^. Frustule pentagonal ; end view quinquangular ; each 
angle concave. 

Var. y. Frustule cubical ; end view square. 

Recent : found among the small Algae, &c., on Hippopns macu- 
latus. 

Plate IV., fig. 10. a, front view ; b, end view. Fig. c, pentagonal 
frustule ; d, square ditto ; e e e e, various aspects of the frustules. 

12. T. arcticum, mihi. Front view broader than long, with the 
ends straight ; clea,rly distinct from the last species. Diam. l-2oOth. 

Beechy Island, Arctic Regions, Dr. Sutherland : and sparingly 
among Diatomaceae from other parts of the Arctic Seas. 
Plate I., fig. 11. a, front view ; b, end view. 

13. T. condecorum, Ehr. Sides nearly straight, or slightly convex ; 
angles slightly rounded off. On an end view the rows of the cells 
diverge from the centre in elegant curved lines. Diam. l-384th. 

Kutzing, S. A., p. 140. 
Fossil in Bermuda earth. 
Plate I., fig. 12. 

14. T. undulatum, Ehr. Sides undulated ; three or four undu- 
lations on each side. Angles pointed. Cells radiating in lines from 
the centre of the valve. Diam. l-480th. 

Kutzing, S. A., p. 140. 

In all tlie specimens I have seen, the posterior plates of silex 
project beyond the undulations of the front plate, giving this species 
a unique asjject. 

Fossil, in Bermuda earth. 

Plate IV., fig. 13. 

1.5. T. amhlyoceros? Ehr. Sides convex; very slightly undu- 
lated. Angles rounded off. Posterior plates not conspicuous. 



ON THE GENUS TRICERATIUM. 251 

Pritchard's 'Infusoria,' 1852, p. 448. Fossil, Richmond, Virginia. 
Diam. 1 -456th. 
Plate IV., fig. 14. 

16. T. memhranaceum, mihi. Walls of the frustule extremely 
delicate ; sides convex. Angles attenuated, ending in minute 
papillae. Frustule dotted over with very minute cells. Diam. 
l-233rd. 

From the Thames mud. Pare. 
Plate IV., fig. 15. 

17. T. acutum, Ehr. Sides straight or slightly convex, and 
drawn to a point more or less lengthened out. Diam. l-720th. 

Surface with irregular cells. 

Kutzing, S. A., p. 140. 

Plate I., fig. 16. 

Fossil, in Bermuda earth ; varying much in form. 

18. T. reticulum, 'EAvc. A minute species. Sides straight. Cells 
small and somewhat irregular. Front view twice as broad as long. 
Suture narrow. Ends round, projecting, somewhat like a Bid- 
dulphia. Diam. l-388th. 

Kutzing, S. A., p. 140. 

Fossil, in Bermuda and Richmond earth, and recent from shell 
cleanings and small algae. 

Plate IV., fig. 17. a, end view ; b, front view. 

Section III. — Ends of the angles entirely rounded off. 

1 9. T. Montereyii, mihi. Ends of the angles enlarged and bluntly 
rounded off". Structure of the frustule stout. End wall elevated in 
the centre of the triangle, with the cells in that part stou(er, and 
gradually diminishing in size to the sides and ends, where they 
nearly disappear. Diam. 1 -300th. 

Fossil, in a stratum of earth occurring near the shore of Monterey 
Bay, N. A., abounding in Diatomaceae. Furnished by Mr. A. J. 
Taylor, of Monterey. 

Plate IV., fig. 18. 

20. T. alternans, Bailey. Ends of the angles divided from the rest 
of the valve by a transverse line. Cells circular. Diam. l-500th. 

Bailey's ' Microscopical Observations made in S. Carolina,' «fec., 
p. 40 ; and ' Soundings,' fig. S5, 56. Smith's ' Synopsis Brit. 
Diatom.,' p. 26 ; plate v. 45 ; plate xxx. 45. 

On the shores of the British Atlantic and Pacific Oceans. 

Fossil in several of the Diatomaceous earths from North America 
and from Monterey, and in Peruvian guano. 

This well-defined species varies greatly in size, both in the recent 
and fossil states. 

Plate IV., fig. 19. a, front view; h, end view. 

21. T.obtusum, Ehr. Sides straight or somewhat concave. Ends 
rounded off. Cells small ; irregular. Diam. 1 -700th. 



252 ON CERTAIN APPEARANCES OCCURRING IN DENTINE. 

Kutzing, S. A., p. 140. 

Fossil, in Bermuda and Richmond earth. Recent in Thames mud. 

Plate IV., fig. 20. 

22. T. semicircular e, mihi. Ends rounded off, and one en4 so 
much so, as to reduce the frustule to a semi-circular figure. 

Fossil, in Bermuda earth, not uncommon, about the size of the 
last species, but varying in breadth. 

Plate IV., fig. 21. A narrow variety. 

In the preceding arrangement of species we have indi- 
cated characters of division which must be received with 
caution. It is remarkable how, in these minute and obscure 
organisms, we find ourselves met with the same difficulties, 
as to any positive laws governing the formation of any generic 
types, as in the larger and more complex forms of animal and 
vegetable life. It appears as if we could carry our real 
knowledge little beyond that of species, and, when we attempt 
to define kinds and groups, we are met on every side by forms 
which set at nought our definitions. With reference to the 
species of the present genus, looking upon T.favus, or mega- 
storriiim, as what we conceive to be the most perfect plan 
(if any) on which this group is constructed, we find all the 
species diverging from it, and carrying us to analogous forms 
in other groups, or lost in them. Placing the perfect trian- 
gular form of T. favus in the centre, we may diverge in lines 
to a circumference ending in one line, in the long-armed 
T. Solennoceros ; itself nearly resembling Desmidium tridens. or 
hexaceros, Ehr. ; in another line ending in a form resembling 
Desmidiiim apiculosum; in another like Zygoceros rhomOus, 
especially in the front view ; in another analogous to Amplii- 
tetras antedilaviana ; and in another to Campilodiscus cribrosus. 

Norwich, June, 1858. 



On certain Appearances occurring in Dentine, dependent on its 
Mode of Calcijication By S. James A. Salter, M.B., 
F.L.S., &c. 

In Kolliker and Siebold's Zeitschrift for 1850, Czermak pul>- 
lished a paper, on some points of the minute anatomy of the 
teeth, whose importance has not, as it seems to me, been 
sufficiently appreciated in this country. No abstract or trans- 
lation of this paper has yet appeared in English, though the 
interest and value of its contents probably equals any single 
other that has a})peared since the earlier writings of Purkinje 
and Retzius. 



ON CERTAIN APPEARANCES OCCURRING IN DENTINE. 253 

Czermak, among other interesting matter, has been the first, 
in this communication, to give a correct explanation of those 
curious appearances of gk)bular, conglomerate formations in 
the substance of dentine, which have been so long an enigma 
to some of our most indefatigable microscopists. 

My object in the present communication has been partly to 
give a summary and confirmation of Czermak's paper, in 
reference to certain points in the anatomy of dentine, and 
partly to add some further observations of my own on the 
same subject and in the same direction. 

The peculiar markings on dentine, known as the " Contour 
lines,^' and their appendages, the irregular patches of small 
interspaces which limit the outer extremities of the contour 
lines, have never received a rational explanation until the 
publication of Czermak's paper ; and the latter appearances 
especially have previously been the subjects of the most far- 
fetched and untenable interpretations. 

The peculiar patches of opaque interspaces, and the globular 
masses of dentine which bound them, have been shown by 
Czermak to be dependent on the mode in which the animal 
material of dentine is calcified, and to a certain extent (though 
I think not sufficiently) he attributes the contour lines to the 
same cause. At all events they are obviously associated and 
produced at the same time and under the same conditions of 
nutrition, and must be considered together. 

The appearances in question are found variously disposed in 
different teeth and in different proportions in different speci- 
mens. It may be remarked, however, that they are always most 
conpicuous in those teeth whose enamel exhibits irregular de- 
velopment ; and in making sections this may be remembered 
for the purpose of selection. It will be found, moreover (as I 
shall presently explain), that there is an obvious relation in 
number and position existing between the contour markings 
in the dentine and the grooves and irregularities on the 
enamel — a fact which I have not seen mentioned, though I 
believe it to be uniform. Czermak has, however, pointed out 
another circumstance not previously described, by which this 
condition may be recognized in the entire tooth — it is the 
appearance of opaque white lines around the fang, formiuf) lohite 
rings : this can be best seen by moistening the tooth for a 
minute and then holding it obliquely by the side of a Imght 
light. Tliese rings, which vary in breadth from the l-50th to 
the 1-lOOth of an inch, are scattered in succession from the neck 
to the apex of the fang : their white opacity contrasts remark- 
ably with the darker, semi-clear, yellower intermediate por- 
tions of the fang. These rings are, of course, abnormal : their 



254 ON CERTAIN APPEARANCES OCCURRING IN DENTINE. 

number varies : I have one tooth — an inferior canine — in which 
there are thirteen rings strongly marked. Of the import of 
these rings I will speak hereafter. 

When, then, a well marked specimen (such as I have repre- 
sented at PI. v., fig. 1) is examined with a low power, the 
arrangement of the contour markings* will be seen as folloAvs : 
— I would, however, first observe that the section should be 
vertical, and of an entire tooth ; for if it be only of a portion of a 
tooth, the relative position and direction of the markings in 
the different parts of the organ cannot be seen, and these cir- 
cumstances are of the first importance for comprehending the 
import of the appearances in question. 

The term "contour lines" originated with Professor Owen, 
I believe, and implies the general similarity which these have 
with the contour of the tooth. The contour of the two, how- 
ever, is not identical, for the markings (in whatever part 
examined) are more divergent than the outline of the tooth ; 
and, passing from within outwards, abut in succession upon 
the external surface of the dentine. In comparing the abso- 
lute contour of any tooth, it will be found that the angle formed 
by its sides is more acute at its summit, or the summit of any 
particular cusp, than the contour markings within. 

In viewing the specimen with transmitted light, it will be 
seen that a series of dark opaque granular patches are arranged 
immediately within the enamel and crusta petrosa in the outer 
portions of the dentine. In the crown of the tooth they are 
usually more distinct and definite than in the fang : they are 
not continuous and do not form an uninterrupted layer, but are 
separated from each other by intermediate portions of normal 
and well-formed dentine. These patches are more or less 
club-shaped, with the butt-end of the club towards the surface, 
and the pointed or attenuated end stretching obliquely in- 
wards and upwards towards the pulp cavity. These patches 
are so irregularly defined that, unless viewed with very low 
powers, their outline can scarcely be said to have any describ- 
able shape. When, however, they are slightly magnified, or 
seen without a microscope at all, they appear to be convex on 
the outer and upper margin, and straight on the opposite side, 
Tlie upper margin and outer extremity are the darkest and 
most defined ; the lower margin and inner extremity are jagged 
and ill-defined. The little elements of the patch are very 
interrupted towards the inner extremity, but are scattered in a 

* I employ the term " contour marJcings " in preference to " contour 
lines," because I intend thereby to include the oiiaque f^ianular ]\atch at 
the outer limit of the lines, as well as the lines themselves — they arc 
essentially one in cause and meaning. 



ON CERTAIN APPEARANCES OCCURRING IN DENTINE. 255 

direction upwards and inwards and are lost. The contour 
inarking is then taken on by a dark linear streak, which passes 
nearly in the same direction as the patch, with a slight curve, 
towards the pulp cavity. The nature of this line does not 
appear with low power ; it merely looks as an opaque streak, 
more or less dark and defined. The patchy as I have observed, 
is most marked near the surface of the tooth : the line, near 
the pulp cavity ; and where they join they are both indistinct, 
and sometimes not to be discerned. The relative direction of 
the contour markings is curious and interesting, and the 
examination of it in the different regions of the tooth is par- 
ticularly important. Czermak does not notice this : indeed, 
his figure, drawn to display the general arrangement, only 
exhibits a very small portion of the tooth — not enough for the 
purpose — and what is shown is faulty, and only approximative. 
For the particular description of the course of a contour 
marking, I will select the region just below the neck of the 
tooth ; they are there peculiarly indicative of their character 
and meaning. In passing from the surface of the tooth to the 
pulp cavity, the contour marking makes a double curve, like 
the letter f, and precisely resembling the primary curves of 
the dentinal tubes in that region. In passing from without 
inwards the first curve presents a convexity outwards and 
upwards, then bending in the opposite direction, the convexity 
looks inwards and downwards, and as the line almost reaches 
the cavity within, the curve still continuing, it passes almost 
perpendicularly up the side of the pulp cavity, sometimes 
apparently joining the line above it. Now it will be seen 
that the curves of the contour marking not only resemble the 
primary curves of the dentinal tubes in a general way, but 
that they are exactly the same in amount at any particular 
spot, and always opposite in direction : as the tubes bend in 
one direction the contour markings bend in the opposite, so as 
to cross the former almost strictly at right angles ; and this 
may be stated as a rule — that the curves of the contour mark- 
ings are in projwrtion to the primary curves of the dentinal tubes 
at any particular spot, and cross them at rigid angles. This 
may be seen by reference to fig. 1. In the crown and fang 
the contour markings are simpler and less curved. In the 
crown they are more horizontal and, passing above the pulp 
cavity, meet over its summit : here the markings are very 
short. In the fang they are almost vertical, and nearly 
parallel with the inner and outer surface of the dentine. The 
lower ones are usually very ill marked, and though they can 
be traced for a long distance up the fang, as they slowly 
approach the pulp cavity, they are indistinct and interrupted. 



256 ON CERTAIN APPEARANCES OCCURRING IN DENTINE. 

Contour markings vary in intensity and number : they are 
most abundant in the root and most marked in the crown. 
In the root, though very numerous, they are often scarcely 
visible. In the crown, when the line is well marked, it is 
always bounded externally by the opaque patch ; but between 
these there are frequently others less marked — in such in- 
stances, lines without patches at their extremities. 

In teeth, with more than one cusp, the upper contour mark- 
ings are confined to their own cusps, and their extremities abut 
against the sides of those cusps ; but the succeeding ones join 
the markings of the contiguous cusps. 

The contour markings are also well seen in a transverse 
section of a tooth, especially about the neck. Here they are 
represented by a series of concentric rings — a horizontal 
section cutting the successive markings at different distances 
from the pulp cavity. In this view Czermak likens them, not 
inaptly, to the year-rings in wood. 

I would here observe that the contour markings are dark 
by transmitted light, and opaque white by reflected. When 
mounted in Canada balsam, with continued heat, so as to allow 
the specimen to soak in the fluid resin for some time before 
it cools, or when mounted in some liquid, the reverse is the 
case. The same also happens when decalcified specimens 
are mounted wet. It is the white opacity of the extremity of 
the contour markings that produces the appearance of rings 
on a tooth fang, already referred to. 

Decalcified specimens exhibit further points concerning 
the contour markings. In preparing these specimens I first 
make the section accurately, as though for mounting in the 
ordinary way ; I then decalcify it by submersion in dilute 
muriatic acid. It is impossible to make even and regular 
sections by cutting the softened tooth, and I therefore always 
make the section before I decalcify it. 

A vertical section thus prepared will be seen to exhibit the 
contour markings strongly. If such a specimen be hooked 
about with needles, so as to break it up, it will be found to 
tear in successive portions in the direction of the contour 
markings, the tear usually being the line of the marking 
itself. By this means the specimen may be broken up into a 
series of triangular portions — the triangles being formed by 
the external surface of tlie dentine and any two neighbouring 
contour markings ; the base of such triangles is outwards, and 
the attenuated apex is inwards, and drawn up the sides of the 
pulp cavity. These triangular slij)s thus produced are the 
intermediate portions of normal dentine, situated between the 
contour marking. Even the well formed dentine tears readily, 



ON CERTAIN APPEARANCES OCCURRING IN DENTINE. 257 

but it is parallel with, and in the same direction, as the contour 
markings. Transverse sections decalcified break up into a 
series of concentric rings, beautifully and exactly regular : it 
is not easy to tear out complete rings, but they are partially 
separable, and are indicated in great numbers ; indeed their 
number seems to be limited only by the mechanical means 
employed to isolate them. Such a specimen is exhibited at 
fig. 2. Now, the breaking up of a vertical section into 
triangular imbricated slips, and of a transverse section into a 
series of rings, is tantamount, in the entire tooth, to a stratified 
or laminated arrangement : indeed, considering these circum- 
stances, as they bear upon the solid tooth, they indicate its 
composition (in one point of view) as a series of hollow cones 
adapted one upon the other. 

Czermak notices the stratification of the dentine, and speaks 
of the strata being loosened from each other : he says, " I have 
succeeded in breaking off whole layers of tooth-substance, 
which had perfectly smooth surfaces." He considers that the 
splittings of the tooth-substance are by no means a resolution 
of the structure into its original elementary parts. He further 
says, — " The ground substance has certainly a stratified com- 
position, but this is usually latent, as it were." It is fair to 
observe that the lamellation of dentine, as exhibited in de- 
calcified teeth, was first pointed out by Dr. Sharpey,* in the 
tooth of the Cachalot whale. It is most readily seen in the 
teeth of large mammalia (elephant, hippopotamus, «Scc.), but 
its import is better understood in smaller teeth, where its re- 
lation to the entire organ can be contemplated at once. 

I may here point out a fact which, if it have been noticed, 
has, I believe, hitherto escaped recording ; at least it has never 
been distinctly expressed. It is, that the contour markings, 
as well as the fracture lines, which so readily occur in the in- 
termediate normal dentine, and are parallel to them, exactly 
correspond to the pulp surface in the progressive formation 
of the dentine — are identical in fact with the junction line of 
the pulp and internal dentine surface at any particular time 
of growth. In contrasting such a section as is exhibited at 
fig. 1, with a series of one-cusped teeth in different stages of 
advancement, this will easily be recognised : the portions of 
dentine seen between the contour markings in viewing the 
tooth from above downwards are, as it were, the successive 
increments by which the organ is built up, and by which the 
original expanded cap of dentine as it first appears, is con- 
verted into an elongated cylinder with a tube up the centre. 

* Quain and Sharpey's Anatomy, p. 978. 



258 ON CERTAIN APPEARANCES OCCURRING IN DENTINE. 

I have dwelt thus much upon this point, as I have presently 
to show how the contour marking is produced by a condition 
common to the entire growing surface of the dentine at one 
time. 

Having said thus much of the general arrangement of the 
contour markings, I Avill describe their anatomy as displayed 
by higher microscopical scrutiny. 

Two hundred diameters will suffice for the magnifying 
power. When the patches are thus examined they are seen 
to consist of globular masses of dentine more or less isolated 
by interspaces, as they are less or more confluent one with an- 
other. The dentine globules (" tooth-substance-balls," as Czer- 
mak calls them) are spheres, hemispheres, or partial spheres, 
usually of normal dentine, and traversed in the usual way by 
dentinal tubes. Their size varies immensely — from l-400th, 
l-300th, or even l-250th of an inch, down to particles of 
granular dimensions ; even l-10,000th of an inch in diameter ; 
indeed there seems no limit to their minuteness. When 
cleanly mounted the outline of the globules is beautifully 
sharp. The interspaces between them vary in form according 
to the number and size of the globules that bound them. In 
contemplating a large interspace one sees the globules and 
partial spheres bulging into it, some bright and clear, others 
looming indistinctly out of focus. Sometimes the interspaces 
are reduced to mere semi-lunar lines of extreme tenuity. 
These appearances are represented in fig. 3. Dentine 
globules are largest in the crown of the tooth, and smallest in 
the fang, especially near the cemental surface : indeed, in the 
latter situation, in passing from the surface towards the pulp 
cavity they regularly enlarge, but while they increase in size 
they become more fused together, the globules are less 
spherical, and the interspaces proportionally smaller. 

I would here remark that the interglobular spaces (as 
ordinarly observed in teeth extracted, allowed to get dry, 
and suljsequently cut into sections) are truly hollow and filled 
with air. This Czermak has enforced. 

The relation which the dentinal tubes have to the dentine 
gloljulcs and the interglobular spaces, is interesting and re- 
markable. The globules are permeated by tubes exactly as 
the other dentine : the face of a large globule sometimes 
exiiibits as many as five or six tubes traversing it. Now, in 
following an individual tube across a mass of globules, one 
observes it follow a regular course, just as if there were no 
interspaces: one follows the tube across one globule, then, 
skipping the interspace, one finds it crossing the next globule 
in a line with its position in the first, and so on. Tliere 



ON CERTAIN APPEARANCES OCCURRING IN DENTINE. 259 

seems an evident continuity. In specimens, in which the in- 
terglobular spaces have been filled with Canada balsam, I have 
seen (as I have believed) the dentinal tubes collapsed upon 
the sides of the interspace, establishing the continuity. Kol- 
liker has seen inore tlian this ; for he says, that in decalcified 
specimens the interglobular spaces are sometimes filled with a 
soft substance, which is traversed by tubes, and " these may be 
entirely isolated like the dentinal tubes." Though I have looked 
for these I have not seen them, but of the fact I cannot doubt 
when stated by such an authority, especially as I have observed 
what amounts to the same in a different phase. 

The linear portion of the contour marking is explained 
in four ways : — First, by a series of secondary curves in suc- 
cessive dentinal tubes ; secondly, by the dentinal tubes being 
locally widened ; thirdly, by interglobular spaces. The two 
first, though producing the same general appearance when 
seen with low powers, are, I believe, essentially different from 
the contour marking dependent on abnormal calcification. 

The interglobular spaces, which form the contour line, are 
usually a few scattered semilunar streaks, when seen with 
high power : sometimes these become confluent, and they 
then form a narrow linear interspace, not wider than a denti- 
nal tube. This latter I have not seen described. Not un- 
frequently, however, it is impossible to find any anatomical 
change, even when examined with the highest power, in the 
dentine that exhibits a contour opacity ; and I can only 
imagine that a difference in density of such a layer relative 
to contiguous layers, probably dependent on its composition 
in the amount of earthy and animal matter it contains respec- 
tively, may possibly produce it. Such an explanation is quite 
in keeping with the rationale of the other element of the con- 
tour marking. 

The explanation of globular dentine, and indeed of all the 
circumstances of the contour markings, is to be sought, and is 
to be obtained, by examination of the pulp, or inner surface 
of the dentine, especially of growing dentine. This is the 
great point of Czermak's paper. 

To obtain a specimen for examination, Czermak directs 
that a tooth (not completely formed) should be s])lit, and then 
the section ground from without inwards until sufficiently 
thin, the pulp surface never being allowed to touch the stone ; 
the preparation is then to be mounted, with the inner, unrubbed 
surface supine. The appearance of such a specimen is thus 
graphically, and, as I can testify, most accurately described 
by Czermak : — 

" The tooth-substance appears then on its inner snrfnco, not as a sym- 



260 ON CERTAIN APPEARANCES OCCURRING IN DENTINE. 

metrical whole, but consisting of balls of various diameter, which are fiTsed 
together into a mass with one another in different degrees, and on which 
the dentinal tnbes, in contact with the germ cavity, are tenninated. By- 
reflected light one perceives this stalactite-like condition of the inner sur- 
face of the tooth-substance very distinctly, by means of the varied illumi- 
nation of the globular elevations, and by the shadows which they cast. 
Here one has evidently to do with a stage of development of the tooth- 
substance, for the older the tooth is the less striking in general are these 
conditions, and the more even is the surface of the wall of the germ-cavity. 
In verj^ old teeth considerable imevennesses again make their ajipearance ; 
these, however, are not globular but have a cicatrized, distorted appear- 
ance. It is best to make the preparation from a tooth, of which the root 
is not perfectly completed. With such preparations one is readily con- 
vinced that the ground substance of the last-formed layer of the tooth- 
substance appears, at least partly, in the form of balls, which are fused 
among one another and with the balls of the penultimate layers ; and one 
also perceives that in general their diameter becomes less and less, some- 
what in the form of a point, towards the periphery of the tooth-substance. 
The majority of these balls is pierced through by one or more tubes, 
cross\vise, from within outwards. Very frequently, however, they appear 
homogeneous, and contain no tubes." 

I will only add, from my own observation, that the globular 
surface is hardly so general as Czermak implies. Often one 
sees a considerable area that is even and flat, and destitute of 
globules. The large globules are always traversed with 
tubes ; those not traversed by tubes are always small. The 
globules, on the germ surface of secondary dentine, are small 
and tubeless ; they are often very minute 

I have found it much easier to obtain specimens than the 
plan proposed by Czermak, by procuring a tooth of which 
the fang is half grown, then introducing the point of a pen- 
knife into its open extremity, and scraping the inner surface. 
Small portions may be detached, which exhibit the globules 
admirably. 

Another method of obtaining specimens, which further 
illustrate the internal surface of the dentine, is the following. 
In rubbing down a section of a tooth, as the operator ap- 
proaches the pulp cavity, the last film of dentine frequently 
bulges into the unresisting cavity, and, instead of grinding up 
into particles, comes away in a little sheet, a little film of 
dentine parallel with the pulp-cavity's surface, the innermost 
layer, and the one last formed. This should be carefully pre- 
served and mounted. On viewing such a specimen l)y trans- 
mitted light, one sees tlie globules scattered about — some 
isolated, others more or less confluent ; and between them a 
pale, rather indefinite structure, uniting the whole into a 
sheet. 

Now, in C'zermak's specimen one sees only the stalactite- 
like surface of the pulp cavity, and the prominent inner glo- 



ON CERTAIN APPEARANCES OCCURRING IN DENTINE. 261 

bules do not appear connected ; whereas, in specimens ob- 
tained as I have just described, they are seen to form part 
only of the innermost layer of dentine. Upon close inspec- 
tion, by transmitted light it is found that the globules are 
composed of well-formed consistent dentine traversed by 
patent tubes, the open extremities of which are presented to 
the eye. The tissue between the globules has a somewhat 
similar aspect, but the tubes appear shrivelled and collapsed, 
or are not indicated (see fig, 4). The innermost layer of 
secondary dentine, viewed under similar circumstances, pre- 
sents the same general aspect : but the globules are tubeless, 
and the intermediate tissue appears homogeneous (see fig. 5). 

But the most instructive specimens are to be obtained from 
the very thin cap of dentine found upon the foetal pulp. The 
thin edge should be cut off, and examined on the inner sur- 
face ; it should be moist, and never allowed to get dry. In 
such specimens the globules are very apparent, but, as Czer- 
mak observes, they do not appear superficial but in the sub- 
stance of the dentine. This he has not explained, but I have 
observed that, by gradually depressing the focus of the micro- 
scope, the first object that meets the eye is the ends of the 
columnar pulp-cells adherent to the surface of the dentine. 
As the focus is earned deeper, these appear more or less 
fused together, and more remotely the dentine assumes a con- 
sistent and definite structure. It is here, in the moist spe- 
cimens, that the focus reaches the globules, and, consequently, 
there is no superficial stalactite-like bulgings of globules : it 
is only in dry specimens that that is seen. Now, if such a 
specimen he steeped in dilute muriatic acid so as to remove all 
the earthy materials, the glohides instai^tly vanish, and the den- 
tine, where they were seen, assumes the same aspect as that where 
they were not seen. No other chanye is produced. The exist- 
ence of the globules, therefore, seems dependent upon the 
presence of earthy material. This suggested to Czermak the 
idea that the organic material of dentine is, during the cal- 
cifying process, impregnated with earthy salts in globular 
forms, and that, by a deeper degree of calcific impregnation, 
the whole tissue is imbued with the hardening element, and 
the globules are fused. Such a doctrine is capable of ex- 
plaining all the circumstances of the case ; and we have only 
to imagine an arrest of calcification at the globular stage, over 
the surface of the pulp as it exists at any one time, to explain 
all the phenomena of the contour markings. 

In teeth which have been allowed to get dry, one would 
imagine that those portions of dentine which have calcified 
would retain a consistent form, while the uncalcified animal 

VOL. I. T 



262 OBSERVATIONS ON THE 

material would shrivel up : hence the stalactite-like appearance 
of the pulp-cavity's walls, and hence also the interglobular 
spaces in a dried tooth, I have shown that, in the innermost 
layer of dry dentine, the globules are held together by an 
attenuated tissue, in which the ends of dentinal tubes are in- 
dicated. Again, the contour lines, which exhibit no inter- 
globular spaces, but which are continuous with imperfectly 
calcified globular patches, may be imagined to be themselves 
dependent on deficient lime impregnation. The integrity of 
such deficiently-hardened dentine would be seriously inter- 
fered with by getting dry ; hence, probably, one reason why 
decalcified dentine so readily tears along these lines. 

Now, the idea that the contour markings are produced by 
an imperfect supply of calcarious material is consistent with 
other collateral circumstances. Upon that idea one would 
imagine that other tissues besides dentine, dependent for their 
maturation on lime impregnation, and the other teeth, would 
suffer at the same time ; that is, believing the effect to be 
produced by a general vice of nutrition : and such, indeed, is 
the fact. The enamel almost always suffers at the precise 
spot where the globular patch abuts upon the surface, rendering 
it irregular and rocky ; and it will constantly be found that 
these appearances are observable on many teeth of the same 
individual ; not at the same spot on all the teeth, but at places 
corresponding with the different degrees of development which 
the various teeth would have attained at one particular period. 

Why the dentine should be thus aborted, so to speak, at 
successive periods of its growth, and why during intermediate 
intervals it should mature perfectly, are questions which can 
only be explained by imaginary successive periodic condi- 
tions of depressed and healthy nutrition in the individual 
during: the formation of such teeth. 



Observations on the Muscular Tissue of the Skin. By Joseph 
Lister, M.B. Lond. F.R.C.S. 

Among the abundant new matter contained in those parts of 
' Kolliker's Microscopische Anatomic ' that are hitherto pub- 
lished, there is perhaps nothing more striking than the 
announcement that small bundles of unstriped muscle exist 
in all parts of the dermis that are provided with hairs, con- 
nected inferiorly with the hair-follicles, just below the seba- 
ceous glands, and passing up obliquely towards the free 
surface of the skin. 



MUSCULAR TISSUE OF THE SKIN. 263 

The effect of the contraction of such little muscles must 
necessarily be to thrust up the hair-follicles and depress the 
intermediate portions of skin ; in other words, to produce 
cutis anserina ; and thus this condition, previously quite un- 
accounted for, received at the hands of Professor Kolliker a 
simple and beautiful explanation. 

In March of the present year (1853) I made an attempt to 
verify this most interesting discovery ; and although the 
somewhat arduous duties of a resident office in University 
College Hospital prevented me from making the investigation 
as extensive as I could have wished, yet 1 found myself able 
not only to verify, but in some slight degree to add to Kolli- 
ker's observations. And as the main fact of the muscularity 
of the skin had not previously, so far as I am aware, found 
confirmation in this country, I have been induced to publish 
my results in the hope that they may prove acceptable to the 
microscopical anatomist. 

Kolliker originally described* these muscles of the skin as 
flat bundles of unstriped muscular tissue, from l-120th of an 
inch to l-75th of an inch in breadth, of which there appeared 
to be one or two in connexion with each hair-follicle : it seemed 
probable to him that they arose from the superficial parts of the 
corium, and he had clearly seen them passing obliquely down- 
wards to their insertion into the hair-follicles, close behind 
the sebaceous glands which they embraced. In his ' Hand- 
buch der Gewebelehre,'t published in 1852, he gives in the 
text exactly the same account of these muscles, except that he 
no longer expresses any doubt regarding their origin from the 
superficial parts of the corium. He afterwards states in a 
note that these muscles had been very recently seen by two 
observers, Ejlandt and Henle, both of whom, however, had 
found them narrower than he. Eylandt, who named them 
*' arrectores pili," had never seen more than one bundle 
connected with each hair-follicle, and had failed to detect 
muscular tissue in the nipple and areola, and in the sub- 
cutaneous cellular tissue of the scrotum, penis, and peri- 
naeum, where Kolliker had described it as existing. Henle 
had traced the muscles to the most superficial parts of 
the dermis, where they divided into numerous little bundles 
1-3000 of an inch in diameter, which could be followed to 
immediately beneath the epidermis ; he had also seen inuscular 
tissue in the nipple, areola, and the other parts where Kolli- 
ker had described it, but, on the other hand, in the opinion 
of Kolliker, he had gone too far, inasmuch as he described 

* Vide Microscopische Anatomic, vol. ii. part i. p. 14. 
t Vide. Handbuch der Gewcbelclirc des Mcnschen, p. 82. 

t2 



264 OBSERVATIONS ON THE 

bundles of plain muscular tissue as existing on the exterior 
of the sudoriferous glands and blood-vessels of parts destitute 
of hairs (such as the palm and sole). These Kolliker is 
unable to discover, and he believes that Henle has been 
misled by the use of boiled preparations, in which, as Henle 
himself states, fine branches of nerves are liable to be mistaken 
for muscle. Thus it appears that the confirmation furnished 
by these two observers is by no means a very satisfactory one, 
and that Henle, the only authority on whom we rest for the 
fact of the muscles taking origin immediately beneath the 
epidermis, cannot, in the opinion of Kolliker, be implicitly 
relied on Avith reference to this investigation. It appears 
remarkable that Eylandt should have failed to discover 
muscular tissue in the scrotum, for the dartos was long 
since proved to owe its contractility to unstriped muscle. 
Of the parts in question I have examined only the areola 
mammae, which, however, answered well to the description 
given by Kolliker, who states* that the bundles of muscle are 
there circularly disposed, forming a delicate layer in the deeper 
parts of the corium, and encroaching slightly on the subcu- 
taneous cellular tissue. On dissecting a portion of an areola 
from the subcutaneous tissue towards the surface, I found on 
reaching the deepest part of the dermis a delicate pale reddish- 
yellow fasciculus circularly arranged ; and a portion of this, 
teazed out with needles, and treated with acetic acid, presented 
in a well-marked manner the nuclei of plain muscular tissue. 
A camera-lucida sketch of a small portion is given on a re- 
duced scale in PI. VI., fig. 6. 

In enumerating the parts where he has inet with muscles 
connected with the hairs, Kolliker does not mention the scalp, 
probably because the density of the tissue of this part ren- 
dered it unfit for investigation by the method in which he 
prepared his objects, viz., isolating a hair follicle with its 
sebaceous glands and treating it with acetic acid. Its very 
firmness and consistence, however, make the scalp better 
adapted for fine sections than any other part of the skin ; and 
as 1 succeeded better with sections than by the other method, 
the scalp has received most of my attention. By compressing 
a portion between two thin pieces of deal, and cutting off with a 
sharp razor fine shavings of the wood and scalp together, mode- 
rately thin slices may be obtained. Fig. 4 represents a perpen- 
dicular section made in this way, and treated with acetic acid ; 
the epithelium has become detached from the free surface ah; 
6 c is part of one of the muscles near its superficial attach- 

* Vide Micr. Anat., vol. ii. part i. p. 14. 



MUSCULAR TISSUE OF THE SKIN. 265 

ment, and it illustrates pretty well the appearance presented 
by them under a rather low power. They are distinguished 
from the tissue around them by their transparent and soft 
aspect, and by the abundant elongated nuclei scattered through 
them. Under a higher power the characteristic " rod-shaped" 
nuclei become fully brought out, and no doubt remains as to 
the nature of the tissue. A good example of nuclei so 
magnified, derived from a muscle connected with a hair- 
follicle of the pubes, is shown in fig. 5. It will be observed 
in fig. 4, that the muscle has been traced to within a very 
short distance of the surface, where the nuclei became 
obscured by other tissues. 

But I afterwards found that much better sections could 
be obtained from dried specimens. A portion of shaved 
scalp being placed between the two thin slips of deal, a 
piece of string is tied round them so as to exercise a slight 
degree of compression ; the preparation is now laid aside 
for about twenty-four hours, when it is found to have dried 
to an almost horny condition. It then adheres firmly by 
its lower surface to one of the slips, and thus it can be 
held securely, while extremely thin and equable sections 
are cut with great facility in any plane that may be desired. 
These sections, when moistened with a drop of water and 
treated with acetic acid, are as well suited for the investiga- 
tion of the muscular tissue, as if they had not been dried. 

Fig. 1 is slightly reduced from a camera lucida sketch* 
of such a section, made in a plane perpendicular to the sur- 
face of the scalp, and at the same time parallel to the sloping 
hairs. I find that such a plane always contains the muscles in 
their entire length, the reason of which will appear shortly. In 
this figure d is the corneous, and e the mucous layer of the 
epithelium ; h, b, . . . . are the hair-follicles with their con- 
tained hairs, both have been more or less mutilated by the 
process of section ; the second hair from the right being a 
short one, its bulb is seen : c c . . . . are the sebaceous 
follicles, also more or less mutilated : a^^ a., . . . . a^ are the 
muscles, which appear, under this very low power, merely as 
transparent streaks, and require a higher power to make out 
their tissue. Tlie muscles are seen to arise in all cases from 
the most superficial part of the corium, and to pass down 
obliquely to their insertions into the hair follicles immediately 
below the sebaceous glands. It will be remarked that the 
muscles are here all on the same side of the respective hair- 

* In all the sketches from which the fii^urcs that illustrate this paper 
have been taken, I have used the camera lucida, which instrument has 
the great advantage of ensuring correctness of proportions. 



266 OBSERVATIONS ON THE 

follicles, viz. on that side towards which the hair slopes : and 
such I found in the examination of a large number of sections 
to be always the case. This is an interesting fact, as such an 
arrangement of the muscles is exactly that which is best 
adapted for erecting as well as protruding the hairs, which 
must be drawn by their contraction nearer to the perpendicu- 
lar direction. That this erection as well as protrusion of the 
hairs does occur, I have proved by artificially exciting the state 
of cutis anserina upon my own arm and leg. Tickling a neigh- 
bouring part will often induce horripilation, and if the eye is 
kept on an individual hair at this time, it is seen to rise 
quickly as the skin becomes rough, and to fall again as the 
horripilation subsides. I have never seen more than one 
muscle to each hair-follicle in the scalp : and in order that a 
single muscle may by its contraction simply erect a hair, it 
must be placed in a plane perpendicular to the surface of 
the skin and parallel to the hair ; this explains the fact before 
alluded to, that a section made in such a plane is sure to 
contain the muscles in their entire length if at all, while 
sections in other planes cut across either the muscles or the 
hairs. 

Fig. 2 represents the superficial attachments of the two 
muscles a^ and a^ of fig. 1 ; a being the upper end of a^, 
and b that of a.^; c is the corneous, and d the mucous layer 
of the epidermis ; the intervening tissue between the muscles 
was omitted in the sketch to save time, b furnishes a good 
example of the subdivision of a muscle into secondary bundles 
near the surface, as observed by Henle, while in a the sub- 
division, if it has occurred at all, is certainly not carried so 
far : the muscle b c in fig. 4 seems not to have undergone any 
subdivision : in some cases a simple bifurcation of a muscle 
near the surface is all that is seen : hence the splitting up of 
the muscles into smaller bundles near their upper attachment 
appears not to be a constant thing, and when it does occur 
exists to a very variable degree in different muscles. Want 
of room in the plate has rendered necessary so great a reduc- 
tion of the scale* from the original drawing, as barely to 
aUow the nuclei of the muscles to be perceived ; by looking 
closely, however, it may be seen that at e and f nuclei exist 
immediately under the epithelium, and before introducing 
them into the sketch, I ascertained, by a higher power, 
that they were really of the same character as those in 
other parts of the muscles. At (/ it was impossible to trace 
the nuclei so far ; if any existed here, they were obscured by 

* Figs. 2, 3, and 4 have all been reduced one-half from the original 
sketches. 



MUSCULAR TISSUE OF THE SKIN. 267 

the fibrous tissue of the scalp, which adheres to the muscles 
throughout their whole length, but appears to form special 
sheaths for the bundles of origin at the surface, and these 
sheaths interfere considerably with the examination of the 
muscular tissue enclosed by them. In some cases, however, 
they seem to be prolonged beyond the point to which the 
muscular tissue reaches, acting as tendons of attachment, and 
this may perhaps be the case at ^ : I have seen one striking 
instance of this mode of attachment, where a muscle having 
divided into two portions at some depth below the surface, a 
pretty long band extended like a cord to the surface from one 
of the divisions, and acetic acid having been added, nothing 
whatever but yellow elastic fibres could be seen in this band 
(the white fibres had been of course gelatinised). As a 
general rule, however, the muscular tissue extends to within a 
very short distance of the epithelium, and often, as above 
stated, can be detected immediately beneath it, as Henle has 
represented. 

In fig. 3 is shown the connexion of the muscle a„ of fig. 
1, with its hair-follicle ; so that were the muscle a of fig. 2 
continued far enough downward, it would join with a of 
fig. 3. The hair and its follicle are seen cut across very ob- 
liquely : h is the hair, tilted somewhat out of its natural 
position in the inner root-sheath c ; d is the outer root-sheath 
(corresponding to the mucous-layer of the epidermis), whose 
outer cells are perpendicular to the hair-follicle ; e is the 
" structureless layer " of the hair-follicle ; f is the circular 
layer of Kolliker ; ^ the external longitudinal layer with 
which the muscle is seen to become blended. Several elon- 
gated nuclei appeared at ff^ ; whether these are derived from 
the muscle, which is evidently inserted a good deal into the 
part of the follicle that is hidden from view, or whether 
they are only the elongated nuclei that occur in all parts 
of the longitudinal layer of the follicle, is doubtful : their 
well-marked elongated character inclined me rather to the 
former opinion ; A is a part of one of the sebaceous follicles, 
which appears to have no special connexion with the muscle 
that simply passes close by it without embracing it, as Kol- 
liker implies, or sending any muscular expansion over it ; and 
the same occurs in fill cases, so far as I have seen ; e is a 
portion of the fibrous tissue of the dermis, showing its con- 
nexion with the surface of the muscle. 

Kolliker's description of the muscles of the skin (see p. 
263) does not Cjuite accord with what I have seen in the scalp, 
either as regards their shape or size. The muscles in this 
part had not, in sections parallel to their course, the aj)pear- 



268 ON THE MUSCULAR TISSUE OF THE SKIN. 

ance of flatness ; and by cutting slices in the way above indi- 
cated, at right angles to their known direction, their transverse 
sections were readily seen, and proved to be often quite cir- 
cular, sometimes somewhat elliptical or polygonal, showing 
their form to be that of more or less rounded bundles. Their 
average diameter is, according to my experience, l-200th of an 
inch, which is less than half the average of KoUiker's mea- 
surements, but this discrepancy is probably due to difference 
of situation in the parts observed, Kblliker not having ex- 
amined the scalp : for one muscle which I sketched from the 
pubes was very nearly 1-lOOth of an inch in diameter. 

With regard to the statement of Henle, that muscular tissue 
exists in parts destitute of hairs, I have searched with dili- 
gence many good sections of both the palm and the sole, 
without having been able to discover any evidence of it on the 
exterior of either the sudoriferous glands or blood-vessels of 
these parts. In a section tieated with acetic acid, the elon- 
gated nuclei of the internal coat of a small blood-vessel some- 
times give it an appearance that might at first sight be mis- 
taken for that of unstriped muscle ; but this is an error easily 
avoided by care, and I cannot but agree with Kolliker in 
thinking that, in some way or other, his boiled preparations 
have led Henle into error. 

In order to verify KoUiker's statement* that no unstriped 
muscle exists in connexion with the vibrissae of mammalia, I 
examined the feelers of a cat. These large hairs extend far 
down into the tissues beneath the skin, and have a more com- 
plex muscular apparatus than the small hairs of the human 
skin. Bundles of muscles extend from the lower part of the 
gigantic hair-follicle obliqviely upwards to the inferior aspect 
of the skin, and, in addition to these, there is muscle sur- 
rounding the large nerve that enters the base of each hair- 
follicle. These muscles were all of the striped kind, but 
extremely soft and extensile, and among the fibres were a 
number of very elongated nuclei, but I saw no distinct evi- 
dence of the admixture of unstriped muscle. 

In conclusion, I may state that this investigation has proved 
to me the general correctness of KoUiker's original observa- 
tions, and also of the results of Henle's further inquiry, 
except in the case of tlie alleged muscularity of parts destitute 
of hairs ; and I shall be happy if the little additional matter 
communicated in tliis paper shall be found to bear as well 
the scrutiny of others. 

University College Hospital, June \st, 1853. 

* Vide Micr, Aniit., vol. ii. part i. p. 15. 



( 269 ) 



TRANSLATIONS. 



Remarks on the Structure and Function of the Retina. By 
H. MiiLLER. From the Verhand. der Physical. Medicin. 
Gesellschaft in Wurzburg. B. III., H. III., p. 336. 1852. 

The view respecting the physiological function of the various 
layers of the retina arrived at by Professor Kolliker, from the 
investigation of the human eye, and which he has detailed in a 
previous paper in these Transactions, I have, also, been led to 
adopt in the most essential points, from continued researches 
respecting that membrane. 

On the one hand, the difficulty, and almost the impossibility, 
of maintaining that the expansion of the optic nerve is the 
perceptive element for objective light becomes continually 
more and more obvious ; and, on the other, the mosaic-like 
contrivance for the reception of impressions separated by 
spaces, which Avas formerly generally assumed as a postulate, 
although in vain sought for, in consequence of the altered 
view respecting the structure of the retina, appears now to be 
admitted ; particularly since it has been shown that the radial 
fibres are continuous externally in " cones " and " rods," but 
are internally in the closest contact with the expansion of the 
optic nerve, and probably in part connected with it. The 
circumstance, that such a radial arrangement of the retinal 
elements occurs in all the vertebrate classes {yid. Zeitsch. f. 
wiss. Zoologie, III., p. 234), notwithstanding all the divers 
variations which otherwise exist in the condition of the indi- 
vidual layers, confers an important significance upon this 
arrangement. But in favour of the notion, that it is the 
radially disposed elements, and not the horizontal fibres of the 
optic nerve, which first perceive the objective light, I find, 
besides the points adduced by Professor Kolliker, a weighty 
argument in the peculiar striictiwe of the retina in the Cepha- 
lopoda, whose much developed eyes, of all the Invertebrata, 
come nearest to tliose of the vertebrate class. 

In the Cephalopoda the innermost layer of the retina consists 
of elongated, slender, transparent cylinders, which are, in 
many respects, similar to the " rods " of the vcrtebrata ; and 
like them densely crowded together, are disposed in the di- 
rection of the radius of the whole eye. Behind these is a 
layer of pigment, which is penetrated by fusiform filamentary 
prolongations of eat;li tylinder. Whence is efl'ected the con- 



270 MULLER ON THE RETINA. 

nexion with the outer layers of the retina, of which the last 
or outermost is the horizontal expansion of the fibres of the 
optic nerve. Thus the arrangement of the elements is one, 
pretty nearly the opposite of that which obtains in the Verte- 
brata. 

In this case, at all events, it is evident that the light must 
penetrate the innermost bacillar layer, in order to reach the 
other elements of the retina. 

At the same time it is hardly conceivable that the light 
should act directly upon the fibres of the optic nerve, which 
lie far behind the pigment, since it is certain that no image 
can be there formed. 

The perception of the latter must rather, in the first instance, 
proceed only from the radially-disposed elements, which alone 
are opposed to the light. 

This function must be assigned either to the continuations 
of the innermost " rod-like " cylinders, coiTesponding in some 
degree to the " cones " of the Vertebrata, and which project 
into the pigmentary layer, whilst the cylinders themselves 
would serve for the isolated conduction of the impression, or, 
it may be, the cylinders themselves are destined for the per- 
ception, and all that lies behind them, merely for the con- 
duction. 

Thus the arrangement agrees very much with the notion, 
which, a priori, appears to be the most plausible ; that most 
internally there is a mosaic layer for the reception of light, be- 
hind that a pigment for the absorption of the light which has 
been admitted, traversed by radial filaments, which communi- 
cate the impression to the horizontal fibres of the optic nerve. 

Now, since in these eyes there can hardly be any doubt 
that the radial elements serve for the perception of the ob- 
jective light, whilst the horizontal are simply subservient to 
the conduction of the impression, a similar condition becomes 
the more probable, also, in the Vertebrata. 

Tlie notion, that the radial elements serve for the reception 
of light, involves a change in the bases upon which are 
founded the considerations respecting the relations of the 
smallest (listingiiishahle retinal images to the elementary con- 
stituents of that organ. 

The difficulty presented in the supposition that very small 
portions of the same fibre, taken longitudinally, were neces- 
sarily to l>e regarded as possessing different perceptive pro- 
perties, is removed, and, what must now l)e admitted, that a 
fibril of the optic nerve merely conducts different impressions, 
appears at all events less objectionable. The comparison of 
the mosaic portion of the retina, witii the calculated propor- 



MULLER ON THE RETINA, 271 

tions of the smallest images, would at the same time afford 
an indirect argument for or against the above view, on which 
account I will add a few statements to those already adduced 
by Professor Kolliker. 

It is easily shown by experiments, as well as from the com- 
parison of various statements (vid. Volkmann, ' Handw.' d. 
Phys. Art. ' Sehen.,' p. 331), that for a single impression, the 
calculated image may be almost infinitely small, if only the 
illumination be sufficiently powerful ; for instance, a small 
hole in a black lamp-shade, or an object glittering in the sun. 
The dimensions, thus obtained by calculation, are so many 
times less than the transverse diameter of the elementary parts 
of the retina in question, that unless a very incomplete union 
of the luminous rays in the eye be assumed, it must be con- 
cluded that it is only requisite that one of these elementary 
parts should be acted upon with sufficient intensity, only in 
a small point, in order to communicate the impression of 
light. 

On the other hand, the possibility of distinguishing the 
smallest distance, shown by Volkmann to exist, might depend 
upon this, whether several luminous pencils are incident upon 
one or several elementary parts. It is necessary, however, 
previously to consider the site of the most distinct vision, 
because as we proceed towards the lateral portions of the 
retina, both the optical and the anatomical conditions become 
more complex. 

Volkmann recognized the duplicity of the two filaments of 
a spider's web, at a calculated distance of the retinal images 
of 0'0044"', and for a friend who had the most acute vision, 
of 0-0025'". 

Valentin (Physiologic, II. 3, Abth. p. 259) distinguished 
the distance of two micrometer lines, with a distance of 
0-0022'" ; and in a second case, with one of 0*0014'", on the 
retina. 

As regards my own eyes, the results derived from the 
observation of a whole series of micrometer lines, or of the 
lines in a steel engraving, under favourable conditions of 
illumination, varied between 0*0025'" and 0-003"'. 

On account of the difference, which, moreover, occurs in 
the perception of lines and points, 1 thought it would be 
necessary to consider the latter also, but I found tliat the 
differences are not very important. The distance from the 
eye at which the lined and pointed spaces of a steel engraving 
can no longer be recognized in their separate elements, but 
appear uniform, was pretty nearly equal, with equal inter- 
spaces between the latter. 



272 MULLER ON THE RETINA. 

Two lines, made with a fine needle-point, with an inter- 
space of 0*2 '", could be recognized as double, at a distance of 
about 3 feet, by transmitted light. If the number employed 
by Volckman (1. c. p. 289 and 331), viz. 6 23'", be applied as 
the distance of the focus from the axial point of the retina, the 
distance between the retinal images would be 00022'" ; in the 
instance of several holes, 1-7'" apart, seen at a distance of 
20 inches, the distance between the retinal images is 0"0037'"; 
in that of a wire-sieve, 44 of the openings in which, taken 
longitudinally, go to an inch, at a distance of about 3 feet, at 
which they were still very distinctly separable, the distance of 
the retinal image is : 0-0039'" ; and at 4 feet : 0-0027'". 

If these calculations be based upon the proportions of the 
eye, given by Listing (Handworterb. der Phys. IV. p. 496), 
it is true that somewhat larger numbers are afforded ; for 
instance, instead of 0-0039'" : 0-0042'". This difference, 
however, particularly in greater distances, is of inconsiderable 
moment. On the other hand, in peculiarly acute eyes and 
under highly favourable conditions, somewhat smaller values 
are presented. 

Now, if the above numbers are compared with the diameter 
of the larger elements in the bacillar layer, viz., the cones 
(bulbs), which KoUiker found to measure 0-0025 — 0-0045'", 
but in the " yellow spot," not more than 0-002 : 0024"', only 
the one statement of Valentine is decidedly less, all the others 
equal, or a little (but within moderate limits) larger than the 
cones of the " yellow spot." The diameter of the " rods," on 
the other hand, is many times exceeded. 

It would be impossible in any case to arrive at an absolute 
correspondence, and particularly do the greater values of the 
distances between the images admit of an easy explanation. 
In general the intervals of several perceptible points must be 
somewhat greater, because the arrangement of the points will 
not readily be exactly conformable to the arrangement of the 
parts of the retina, and consequently the image of a point 
sometimes falls between, or in other words, upon two retinal 
elements ; sometimes a single element will be touched by the 
images of two points. 

In greater measurements this must take place, for the reason 
that the focus never represents an absolute point, but small 
circles of diffraction, and the larger these are in the eye, so 
much the less will it be in a condition, as Volkmann has 
stated, to appreciate the smallest distances. 

By the circumstance that the image of a point touches 
several elements, the phenomena of irradiation may be ex- 
plained, within certain limits. The distinct perception, also, 



ZENKER ON DAPHNID.T:. 273 

of two points, the distance between the image of which is not 
quite equal to the diameter of one of the retinal elements, 
might, according to the above view, be possible in a very 
acute eye, because the image in a particular position might 
nevertheless touch two different elements. 

Thus, the facts hitherto ascertained, appear, in general, not 
to be opposed to the notion that the perception of the smallest 
distances depends upon the circumstance that different ele- 
ments of the bacillar layer are touched by the image, and 
this correspondence again, equally favours the view that, that 
layer is the apparatus for the reception of the luminous 
impressions. 



Physiological Remarks on the Daphnid(B. By Dr. W. Zen- 
ker. Mailer's Archiv, 1851, p. ll'i, PI. III. 

An organ, occurring in the Daphnid2e, about which a good 
deal has been said, is the curious " black spot" in the head, in 
front of the eye. It is seldom entirely wanting, as in Daphnia 
hrachiata, D. cornuta, M. E. {Eunica longirostris, Koch, Lyn- 
ceus longirostris, Miiller, Bosmina longirostris, Baird), and 
Polyphemus ; is much elongated in D. sima, and is so large in 
the genus Lynceus, Mull., that it was considered by O. F. 
Miiller as a second eye (Entomostraca, 1792, p. 67). Sub- 
sequently, it has been looked upon as an auditory organ 
(Schodler, iib. Acanthocercus rigidus, Wiegm. Arch., 1846, 
bd. 1). It consists invariably of a minutely gianular, black 
substance, without a vestige of crystalline lenses or similar 
organization, and is situated immediately upon the brain, or, 
at all events, is only separated from it by a very short nerve. 
It occurs not only in the Daphnoida, including the Lynceidae, 
Baird, but Lievin has also noticed it in Hedessa Sieholdii, a 
new monoculous Phyllopod. (Branchiopoda der Danziger Ge- 
gend. 1848, p. 11, PI. II., fig. 10.) 

In the full grown animal the function of this organ is not 
readily made out with certainty, whilst, on the other hand, it 
is during the embryonic development of the animalcules within 
the mother that the nature of this black spot is most clearly 
evident. It is known that in the embryo of the Daphnidae 
there are at first two eye-spots on both sides of the head, 
which unite into a spherical mass not long before birth. At 
a time when the eye-spots are only faintly indicated, and of a 
brown colour, there is evident, seat(;d on the brain, below and 
in front, a solitary sharply defined deep black speck, in which 
may at once be recognized the black speck of the full-grown 



274 ZENKER ON DAPHNID.E. 

Daphnidae. It is necessarily formed long before the eyes, and 
is thus the first developed organ of sense. 

If now it be asked, what organ in the allied Crustaceans, 
and especially in the Phyllopoda^ corresponds with this, it 
will be found in the tripartite azygous eye, which occurs so 
extensively under various conditions throughout the Crusta- 
ceans, It occurs as the only visual organ in Cypris, Cyclops, 
&c. ; in conjunction with the aggregated eyes in Artemia, Ar- 
gulus, &c. ; but it appears regularly in all the Branchiopoda 
and Siphonostomata as the earliest visual organ. It is always 
placed immediately on the brain, thus also showing its corre- 
spondence with the black spot of the Daphnidae. 

Another question is, whether this spot, the nature of which 
we have developed in agreement with Siebold's supposition 
(Vergleich. Anat., 1 848, p. 445), actually fulfils the function 
of an eye during the period of embryonic life, or whether, in- 
dependently of any such utility, it is formed merely in accord- 
ance with the law of development of the Branchiopoda. As 
the shell of the Daphnidae is transparent, a certain impression 
of light may be conveyed to the embryos ; but as the embryo, 
so long as it does not possess freedom of motion, has no need 
to distinguish objects, so there is no necessity for any refractive 
body. The other Branchiopoda must, however, before they 
have other eyes, move about freely in the water, and are, 
therefore, provided with refractive bodies. In these the pig- 
ment of the eye is for the most part red ; in D. Fulex, on the 
other hand, it is brownish red, and in Sida crystallina^ black. 

It therefore does not appear to be essential what form this 
black spot may occasionally assume in the full-grown animal. 
In the embryos it precisely resembles the form of the eye of 
Cyclops. In the young D. sima it is round, also for some 
time after birth ; at a later period it becomes elongated. Un- 
fortunately, I have not observed in those Daphiaidae, in which, 
when fully grown, the spot is wanting, whether they possess 
one in the embryo state. 

There is no doubt that an isolated Daphnia will of itself 
produce new generations, and that these again will bring forth 
others without impregnation, and so on for many times, and 
probably without limit. This mode of propagation, which 
occurs in some Insects, is one distinct from all others, and 
cannot be identified either witli gemmation or witli an alter- 
nation of generations. Gemmation does not take place in the 
ovary [why not?], and an alternation of g(»nerations does not 
take place in cases where the same female individual can 
produce young, being first unimpregnated and tiien impreg- 



ZENKER ON DAPHNID^. 275 

nated. Moreover, after impregnation there is absolutely no 
difference in the development of the ovum, except that the 
impregnated ovum comes to be enveloped with a firm, cor- 
neous, saddle-shaped shell (the so-called Ephippium). In 
the Phyllopoda this distinction even appears to fail, as Lievin, 
who had noticed both the male and female in Hedessa Sie- 
boldii, makes no mention of ephippian ova. 

The males of the Daphnidce, it is true, are found all the 
summer through ; but very seldom, and, as it would seem, not 
of every species. On the other hand, towards winter they 
become much more numerous, so that the winter is the fittest 
season for the study of their sexual relations. All the species 
of Daphnida3 succeed each other in the production of male 
individuals. The males of most of the true Daphnioi are met 
with in October, whilst those of Lynceus abound more towards 
Christmas. In consequence of impregnation a large number 
of ephippia are produced, in which the ova are probably more 
protected against decomposition or untimely development than 
from cold. The same succession prevails with regard to the 
ephippia, in the different species, as in the appearance of the 
males. It would thus fairly appear that the ephippia are a 
product of impregnation. Direct experiments, however, have 
not as yet been instituted, to determine whether impregnation 
precedes each ephippium, and each impregnation is followed 
by an ephippium. At last, as the temperature lessens, scarcely 
any but males are produced, and the animal disappears from 
the water ; at the bottom of which, however, in the submerged 
ephippia, provision is made for the revival of future gene- 
rations. 

The males are distinguished, even externally, from the 
females by the different formation of certain members, espe- 
cially of the anterma?, the first pair of legs, and the tail ; for 
the most part, also, in the size and width of the body, the 
males being smaller, and wanting the uterine cavity under the 
back. Internally the testis may be distinctly recognized as a 
single organ, corresponding in form and position with the ovary. 
Evadne Nordmanni is the only species in which, up to the 
present time, the existence of the testis has been indicated 
with certainty by Lievin. 

The simplest form of this gland is presented in Sida crystal- 
Una. If the creature be placed on the side, the testis lies 
immediately upon the intestine, and is at once seen wlicn the 
focus of the microscope is a little raised. It is parallel with 
the intestine, about half as broad, and extends from the last to 
the first pair of feet, being curved at the extreinitv, which looks 
forwards. The opening of the gland is situated in the tail, on 



276 ZENKER ON DAPHNIDiE. 

the abdominal or pedal aspect. This opening varies but little 
in its position throughout the Daphnidae. The analogy 
between the testes and ovary is most evident in Sida., and they 
might readily be confounded, were not their contents very 
different. Whilst in the female, the ova, with germinal vesicle, 
and surrounded with a vitelline substance, are evident, the 
contents of the testes, which exhibit in all respects similar 
forms, consist of the well-known nucleated, immotile, sper- 
matozoid cells, which are peculiar to some Crustaceans. They 
are formed in the curved C£ecal extremity of the testes, from 
cells, the structure of which, on account of their minuteness, 
carmot be further made out. The spermatic cell, however, 
itself, is only about 0.001'" large. 

In this species the male differs externally but little from the 
female. It is somewhat smaller (males 1.0"', females 1.2"'). 
The antennae are two-jointed, and the basal joint runs out into 
a strong lateral spine, supporting a serrated seta, and pushing 
the second joint to the side. The latter supports the antennal 
seta, minutely described by Schodler. 

As the genus Daphnia stands nearest to Sida in the sim- 
plicity of the intestinal canal, so does it also in the simple 
construction of the testes and ovary. The difference between 
the two genera is exhibited more in the arrangement of the 
muscles and the form of the joints than in the viscera. Thus 
the testis in D. Pulex is exactly as in Sida crystallina. The 
antennae, also, are formed in an analogous way, except that they 
are jointed. The beak of the male projects a little more than 
that of the female. The caudal portion of the body supports, 
besides the usual caudal setae, a motile papilla, in the same 
situation as that in which, in the female, the teeth for the 
retention of the ova are placed. This papilla, which is pecu- 
liar to the male of Daplinia Pulex, is covered with scales, and 
resembles in many res})ects the points at the margin of the 
shells, within which it is fi'equently placed, in order to draw 
the body of the animal more firmly between the shells. Neither 
Jurine nor Strauss figure this papilla, nor is it mentioned by 
Lievin. The male is considerably smaller than the female. I 
have also had an opportunity of observing the very interesting 
formation of the sexual organs in the genus Lynceus. It differs 
from that which obtains in Daphnia principally in the curved 
or twisted intestine ; and as in the previous case, so also in 
this, does the testis piesent a corresponding relation. It is 
curved backwards once, j)arallel with the intestine on both 
sides. Here again, also, is shown an analogy with the ovary, 
which itself runs straight between the first and fourth pair of 
feet, but the excretory du( t of which follows the curvature of 



ZENKER ON DAPHNID^E. 277 

the intestine. At its caecal extremity the testis is again curved 
backwards and inwards ; but it is not there only that its secre- 
tion is formed ; this is produced, also, in certain caecal pouches, 
which branch out from the testis in a backward and upward 
direction. Both testes open in the tail, at the point above 
indicated ; their vasa deferentia continue separate to the last. 

These points are seen most simply in L. macruriis, which 
differs from the female only in the form of the antennae ; 
possessing, however, the same broad form and long tail as 
the latter. 

In L. lamellatus the testis between the curvature and the 
opening is furnished on each side with a large vesicle, which 
may be termed a vesica copulativa, and fiom which the secre- 
tion may be expressed. The above, with the addition of 
L. sphcBricus, are the only Daphnidge with the males of which 
we are acquainted. The time to look for the rest is the w inter. 
I suppose, from the similarity with the Phyllopoda, which has 
already been so frequently adverted to, that the males of that 
family also will be found principally in the winter. 

[In Cliirocepluilus dlaphanus, Prev., Branchipus stagnalis, 
M.E., the number of males is very considerable, and pretty 
nearly equal to that of the females at all times of the year. 
This fact seems to afford a curious confirmation to Dr. 
Zenker's opinion, that the chief object of male impregnation 
is the production of ephippian or winter ova. In the case of 
Chirocephalus this provision becomes repeatedly necessary 
during the year, and not towards winter only ; for it is a re- 
markable fact, on Blackheath, at all events, that the Chiro- 
cephalus is never found in any of the several ponds on the 
heath, except in those which dry up completely, at least 
once, but in most years several times, or for the whole sum- 
mer continuously. The ponds inhabited by the Chirocephalus, 
in fact, are merely pools formed by the drainage from the 
roads. Now it is manifest, under these circumstances, that, 
were not provision made by the formation of winter ova, or 
ova having a thick double coat for the revival of the race 
after the drying up of their habitation, it would become ex- 
tinct. We accordingly find that such provision is made in 
the numerous males at all times present. The extraordinary 
power possessed by the ova of Chirocephalus of resistance to 
the effects of desiccation is very remarkable, as is also the 
readiness and rapidity with which they are developed when 
again subjected to the influence of water. If the basin of a 
small pool which has been dry, and even dusty, for months, 
becomes filled after a few days' rain, the water will be found 
swarming with myriads of Chirocephali in about ten days or 

VOL. I. u 



278 SCHULTZE ON THE CHLOROPHYLL OF PLANTS. 

a fortnight. Or if a piece of the dried Ijottom of such a pool 
be placed in a pailful of water, numerous CldrocepJiali will be 
hatched from it in the same time. The reason for this curious 
arrangement with respect to the Cliirocepkali is obvious 
enough. These delicate creatures, themselves vegetable 
feeders, are the prey of innumerable enemies ; among the 
chief of which are the larva^ of Dijtiscus, and of dragon flies, 
&c. In ponds which never dry up, these voracious enemies 
have time and opportunity to destroy the whole race of Ckiro- 
cephali ; but in the favourite haunts of the latter, their enemies 
not being able to survive the drying up of the water, are 
cleared off on each such occasion ; and the Chirocephali, being 
rapidly hatched, have, as a race, time to propagate and deposit 
their posterity in safety for another resurrection. — Ed.] 



On the Identity of a Colouring Matter present in several 
Animals with the Chlorophyll of Plants. By M. Max 
ScHULTZE, of Greifsviald. Comptes-rendus, Tome xxxiv. 
pp. 683. May 1852. 

The author enumerates several animals of a green colour, 
which are common in ditches and marshes — such as Hjjdra 
viridis, several gi-een Turhellaria;, Vortex viridis, 3Iesostom.%im 
vindatrim, and Derostomum ccecum ; and also several green 
Infusoria, such as Stentor polymorphiis^ Ophrydium versatile, 
Bursaria vernalis, (Sec. The colour in these animals is affcjrded 
by minute green globules, about 0.016 inch in diameter, which 
are situated under the integument in the parenchyma of the 
animals. Tliey are perfectly spherical, and exhibit within 
the green substance an extremely minute, colourless, and 
homogeneous nucleus ; or they may consist of several minute 
green globules, grouped together in a mulberry form ; in this 
latter case they arise from the division of a homogeneous 
vesicle. 

Tlii-s green colouring substance is not altered I)y dilute 
acids or alkaline solutions ; by which it is distinguished from 
the green colouring matter of several Alga?, which according 
to Niigeli is changed into a yellow orange or red by the same 
re-agents. Concentrated sulphuric; and muriatic acids dissolve 
the colouring matter ; the solution is of a l)eantiful green or 
bluisli green colour, unchanired by the action of heat ; it is also 
dissolved by a concentrated solution of potass — by ammonia, 
alcohol, and aether, th(> colour |)rccisely resembling that of a 
solution of clilorophyll. 



BLANCHARD ON THE BLOOD IN THE ARACHNIDA. 279 

Its development, also, is influenced in the same way as 
that of Vegetable chlorophyll by light ; but animals con- 
taining it do not evolve oxygen, and the author thence con- 
cludes that the evolution of that gas is not solely dependent 
upon the chlorophyll in plants. 

In Vo7-tex viridis, the minute green globules, owing to their 
mutual compression, assume an hexagonal form — the green 
compartments thus formed are separated by an interstitial 
colourless substance. The existence of a colourless membrane 
around each green vesicle may thence be deduced. This fact 
is further demonstrated in vesicles, the green matter of which 
only partially fills the globular cavity. 

With respect to the chemical composition of the membrane 
and of the nucleus of the vesicles in Vortex viridis, the results 
of the author's researches are limited to the following facts, — 
the solutions of potass, and of ammonia, and sulphuric acid, 
after the extraction of the colouring matter, cause the mem- 
brane to swell out, in which the nucleus can no longer be 
recognised. The membrane becomes pale and finally dis- 
appears entirely, but especially so after long boiling. Acetic 
and chromic acids and alcohol do not affect the membrane and 
the nucleus. By solution of iodine the vesicle is coloured 
brown, the nucleus becomes more distinct, but its colour is 
unaltered. It cannot consequently be assimilated to the nucleus 
of the vegetable chlorophyll vesicle, which most frequently 
consists of amylum. 



Observations on the Circulation of the Blood in the Arachnida. 
By M. Emile Blanchard. Comptes-rendus, Tome xxxiv. 
pp. 402. 

By the injection of the blood-vessels of a large Myr/ale {M. 
Blondii) M. Blanchard was successful in tracing and dissecting 
all the arteries distributed to the various organs, to their ulti- 
mate ramifications, which he describes. The venous system 
is much less perfect, consisting for the most part of canals 
without walls admitting of their being isolated by dissection — 
except in certain situations. He concludes in remarking that 
the circulation of the blood in the Arachnida is effected by 
means of an arterial system of the most complete kind, and 
of a venous system very imperfect it must be confessed com- 
pared with tliat of the Vertebrata, but which nevertheless, 
owing to the great regularity of its course and its limits, 
which are so well circumscribed, exhibits a degree oi perlec- 
tion not, hitherto, well established. 

V 2 



( 280 ) 



REVIEWS. 



The Sea-side Book ; being an Introductiox to the Natural History 
OF the British Coasts. By W. H. Harvey, M.D., M.E.I. A., &c. 
London. Van Voorst (sec, ed.), 1849, pp. 2G4, 12mo. 

A NOTICE of this work, published in 1849, may seem some- 
what out of date in 1853 ; but, in the first place, even had not 
the brief existence of this Journal necessarily prevented an 
earlier reference to it, we do not think that the mere lapse of 
time since its appearance should deter us from recommending 
to our readers so pleasant and instructive a companion, espe- 
cially at this season of the year, when so many of them, as 
we hope, will be preparing for a sea-side ramble, and about 
to enjoy, for health or relaxation, the vivifying breezes of the 
ocean. j\ either is a notice of the book out of place in this 
Journal, seeing that Dr. Harvey has devoted a chapter, and a 
very interesting one, specially to the " Microscopic Wonders 
of the Sea."* 

The "sea!" that magic word to the wearied denizen of 
towns, whose only glimpse of nature, perhaps for eleven 
months in the year, is obtained in a dusty, suburban road, or 
London square ; — with what varied tastes are its refreshing 
breezes sought, and in what different senses enjoyed ! but to 
none, perhaps, does it offer greater attraction than to those 
who delight in inquiring into the microscopic world of nature. 
Nowhere in her wide domain will be found so many, and 
such diverse objects of microscopic research as are afforded in 
the sea, and on its rocky or sandy shores. On rock or sand, 
bare, or covered with tlie russet garb of Nereis, the diligent 
seeker will never fail to find subjects for contemplation, end- 
less interest, and instructive study. The pages of tlie Trans- 
actions of the Microscopical Society alone, bear witness to 
the numerous objects of research afforded in the tiny denizens 
of the sea ; and to the attentive microscopic study of these 

* The lii^li estimation in wliich Dr. Harvey's hook is justly held, may 
be deduced troni the fact that an influential Society has thought it ex- 
j)cdient (wliether properly or otherwise is another question) to imblish a 
very clos(! imitation of it, under the name of tlie ' Book for the Sea-side ;' 
with reference to whicli all we would observe is, tliat the external imitation 
has been mucli more successfully executed than the internal. Our readers 
will observe th;it the ' Book for the Sea-.side ' is not the ' Sea-side l>ook' 
that we recommend to them. 



HARVEY'S SEA-SIDE BOOK. 281 

creatures are we greatly indebted for many important ad- 
vances which have of late been made in physiological and 
anatomical knowledge. To these creatures, as well as to 
many others, Professor Harvey's little work will afford a 
pleasant introduction. All, of course, do not take interest in 
tlie saine subject ; and here we naturally address ourselves 
only to those whose predilections may incline them to inves- 
tigate the habits and structure of the minutest works of 
Nature, with which the shore will so abundantly supply them, 
or with which they may supply themselves, by the aid of very 
simple appliances. 

In his fourth chapter, Professor Harvey, in discoursing of 
the " Zoology of the rocky sea-shore," says — " In the vegeta- 
tion of the sea nature has provided both shelter and food for 

an infinitude of animals Troop after troop of animals, 

one more highly organized than another, either derives its 
nourishment from the sea-weed itself, or uses the submarine 
forest as a hunting-ground, where it fulfils the appointed 
course of its busy life. Adhering to the roots of sea-weeds 
we find the scarcely organized, but obviously animated, 

sponge I'o the stems and leaves adhere multitudes of 

incrusting animals, some of which, till we examine them some- 
what closely, and watch their animal motions and propensities 
with some care, seem to consist merely of masses of jelly ; while 
others display in their outward forms the branching appear- 
ance of mosses ; every branch clothed with scales, and crowned, 
when the animal is in vigour, with starry flowers." 

The latter class, or the so-tei'med zoophytes, will almost 
everywhere afford the most varied and interesting objects for 
microscopic observation. For an account of the different 
species to be met with on the British coasts, the best works 
of reference are Dr. Johnston's ' British Zoophytes,' or for 
those who may be content with a less extensive work — a little 
book, of which we have given a notice in a previous num- 
ber — Dr. Landsborough's ' Popular British Zoophytes.'* Some 
of these creatures will be found adhering to the side of almost 
every rock-pool left by the retiring tide, or adhering to the 
roots or leaves of numerous y«c?. Many appear to prefer old 
shells or loose pebbles, and some of the most beautiful and 
interesting forms will be found in such situations ; in ap- 

* We should here, also, have referreil to Mr. Gosse's recent work, " A 
Naturalist's Kamhles on the Devonshire Coast," but it has not conio into 
our hands until these sheets are passing through the press. We reserve a 
notice of this highly interesting booi — particularly to the Microscoiiist — 
for our next number, in the rnjanwhi strongly recommending it to our 
readers. 



282 HARVEYS SEA-SIDE BOOK. 

pearance to the naked eye — nothing but a scurfy scale. 
These rocky or tidal pools should be often and diligently 
searched ; for the number and variety of minute animal and 
vegetable forms to be found within the narrow precincts of 
one of these Lilliputian lakes is astonishing. " Nothing," 
as Dr. Harvey says, " can exceed the beauty of a clear rock- 
pool seen under strong sunlight, and through a calm surface, 
tenanted by its various animated tribes, all fulfilling the duties 
allotted to their several kinds." In them will be found, ad- 
hering to the weeds, or to the rocks themselves, an infinitude of 
species of Zoophytes, sponges, minute crustaceans, and the 
elegant forms of different LucemaricB, together with many of 
the smaller and most delicate^?<c2. Leaving the rocks for the 
more sandy parts of the shore, we shall find "along the 
margin of the tide, as well as at different levels of the beach, 
and in the crevices of the rock-pools, small patches of drifted 
sand and shells, the examination of which will often afford 
the patient explorer a rich treat," — " Careful examination with 
a lens will generally detect a multitude of minute shells, some 
of very strange shapes, and others structures of great elegance." 
These are the various species of Foraminifera, with many of 
which, in the dead state, most of our readers are probably well 
acquainted ; few, however, have studied them in a living con- 
dition, and this study we would recommend as one of great 
interest and importance. The same drift-sand will often be 
found to contain a " wonderful variety of minute spiral uni- 
valve shells," " though these are scarcely of so small a size as 
to come within the list of genuine microscopic objects." 
" Others may be obtained by the gatherers of sea-weeds with 
little troulile, if they will only preserve the sediment that 
collects in the water in which the sea-weeds are washed." 
" When the sea-weeds are plunged into fresh water, these 
minute molluscs (^Rissoce) are quickly killed, and fall to the 
bottom, and may then be secured by simply straining the 
water through a piece of canvas. Many other minute and 
curious animals, and sometimes Diatomacece^ may be collected 
in a similar way." 

Having thus surveyed the rocks, and sands, and weeds of 
the shore al)ove low-water mark — if we launch upon the deep 
itself, a similar al)undance of minute and interesting forms is 
still presented to us. A small muslin Ijag, the mouth of 
which is kept open by a wire-ring aliout 4 inches in diameter 
— towed slowly behind a boat, on a calm and bright day in 
any sheltered hay or inlet — will he found to gather multitudes 
of creatures of the most beautiful forms, and occasionally most 
'•rilliant colours creatures whose crystalline substance affords 



HARVEY'S SEA SIDE 1300K. 283 

to our wondering gaze a ready insight into many things con- 
nected with the structure of the lower animals, which will in 
vain be sought elsewhere. In this way are collected the 
numerous species of minute naked-eyed Medusic, so well 
described and graphically figured in Professor Ed. Forbes' 
work,* cited below, and which should accompany every 
microscopic observer to the sea-side. Nothing can be con- 
ceived more elegant and graceful than the motions of these 
minute crystalline bodies in a glass of water. Some as bril- 
liant as diamonds with tiny emeralds set round the edge ; 
others like the beautiful Turris neglecta, resembling rubies 
encased in crystal — rising and sinking through the clear water 
with the most easy and elegant movements. In the dark, also, 
most of these little geins will be seen to be furnished with a 
row of luminous spots around the edge of the disc, at the 
base of the tentacles, and it is to them, in great measure, that 
the luminosity of the sea is owing. On almost every part of 
the coast, besides these forms and the allied Beroes, the tow- 
ing-net will frequently gather innumerable specimens of a 
creature resembling a slender spicula of glass, about an inch 
in length, but which is so slender and so transparent as to be 
almost invisible except in a particular direction of the light — 
this is the Sagitta bipunctata, and its simple structure affords 
an excellent subject of microscopic research. When fishing 
for objects of this kind, it is best to have in the boat a large 
white basin half filled with sea-water, and into this the towing- 
net is to be inverted and gently shaken every now and then. 
In this way the delicate creatures it contains will come out of 
it without injury, and though themselves, perhaps, at first 
wholly invisible, their shadows will be seen with great dis- 
tinctness against the white bottom of the basin, and thus many 
forms which might otherwise altogether escape observation, 
be rendered evident. 

The microscopic wonders of the sea, however, are still far 
from exhausted ; it presents as many, if not more, curiosities 
at the bottom, where its depths are never opened to view, than 
at the surface. The best and most convenient mode of obtain- 
ing these, is by the use of an instrument, with which all, 
perhaps, are acquainted in one shape or another, viz., the 
dredge ; but the naturalist's dredge is not a stone dredge, or a 
mud dredge, or an oyster dredge, or in fact anything but what 
it is, the "naturalist's dredge." An instrument of this kind 
is figured and described by Dr. Harvey; but its construction 
is very simple, and may be effected, if need be, by almost any 

* Trof. Fi. Forbes. T5ritisl\ Naked-cycd MctUisiv. A Mono2;rapli. Tub- 
hshed by tho Uay Society. 1847. 



284 HANNOVER ON THE 

country blacksmith. The essential qualities of a dredge of 
this kind are, a small and convenient size, with sufficient 
weight to ensure its sinking to, and keeping at, the bottom, 
even when at a considerable depth and drawn with some 
velocity through the water. The dredge we have been in the 
habit of using for several years past is made of cast-iron, 
which reduces the cost considerably — and it is in practice 
found to be sufficiently strong. It is about 18 inches in 
length, and the opening is about 4 inches wide — the two sides 
diverging outwards, at a slight angle, and coming to a sharp 
edge. It packs with the net-bag in a box about 2 feet long 
and 6 inches wide and high, and consequently makes a con- 
venient-sized package. For the little information requisite 
in the use of the dredge, we would refer to Dr. Harvey's 
chapter on the subject, and will merely remark, that " dredg- 
ing " will be found as pleasing and interesting a pursuit at 
the sea-side as any that can be there followed, and one that 
more than any other will, at times, be rewai'ded by an abundant 
harvest of objects of natural history. 

Recommending our readers thus to invade the domains of 
Neptune, armed with microscope, towing-net, and dredge, we 
can assure them that no one will have cause, even in the most 
secluded nook of the coast, to complain of a single dull hour, 
and if he does not return to his labours reinvigorated both in 
body and mind, and with a fund of subjects for instructive 
contemplation for the year to come, all we can say is — that 
it will be entirely his own fault. 



On the Constkuction and Use of the Microscope. By Adolphe 
Hannover, MD., &c. Edited by John Goodsir, F.R.S.E.,&c. Edin- 
burgh. Sutherland and Knox. 1853, pp. 100. 

Dr. Hannover's book is short, which is a great recommenda- 
tion, and it contains many judicious and useful observations, 
and is evidently the production of an experienced micro- 
scopist ; but we really can scarcely find in it much that should 
entitle it to appear in an English dress, as it is quite evident 
that the author is totally unacquainted with the pi'esent state 
ol the mi(Toscope in this country, however familiar he may 
be with those of foreign construction. He does not mention, 
and appears to be unaccjuaintcd with any English microscoj)e 
maker except Mr. l^it(;hard. Were he aware of what they 
have done, and still are daily doing, towards the perfection of 
the microscope as an instrument of scientilic research, Dr. Han- 
nover would surely have referred to the labours of Ross, 



CONSTRUCTION OF THE MICROSCOPE. 285 

Powell, and of Smith and Beck ; men who, with the aid of 
Mr. Lister, have done more in the improvement of the achro- 
matic microscope than all the continental opticians together, 
and whose instruments, both for optical perfection and 
mechanical contrivances are, as we believe, unrivalled by 
those of any country in the world. But we are indeed sur- 
prised that his learned English editor should have been 
content thus to ignore the merits of his countrymen, and to 
omit all notice of some of the most important improvements 
in the microscope and its appliances, which have now been 
long in daily use. Many other proofs of Dr. Hannover's 
want of information on the points to which we have referred 
might be adduced, but we would merely, in justification of 
what we have said, remark, that he appears to be quite 
ignorant that object-glasses may be made to adjust to varying 
thicknesses of the glass employed to cover an object (pp. 25, 
59), although the mode in which this adjustment might be 
made was described by Mr. Ross as long ago as 1837, and has 
been universally adopted by English opticians since that 
time. He makes no mention either of any of the more 
recent, ingenious, and most valuable modes of illumination, 
to which, for some time past, so much and such successful 
attention has been paid. We refer more particularly to such 
contrivances as Gillett's condenser, and the parabolic reflec- 
tors of Wenham and Shadbolt. 

The book, however, as we have said, contains many 
judicious observations and directions useful to the young 
microscopist ; and the preliminary observations present, in a 
small compass and in plain language, as good an exposition 
of the principal optical considerations which are concerned in 
the structure and use of the microscope, as can, we think, be 
anywhere found within the same limits. 

The first chapter is devoted to an account of the simple 
microscope ; and chapter ii. is on the construction of the com- 
pound microscope and its accessories ; but neither in these 
nor in the subsequent chapters, containing directions for the 
tise of the instrument, do we observe anything from its novelty 
worthy of particular notice — at all events by those who have 
it in their power to refer to Mr. Quckett's much fuller and 
more piactlcal work. 

The author's observations on Micrometry are good, and 
will be found worth consultation, as is also what he says 
about the modes of estimating the magnifying power of an 
instrument, and for calculating the amount of spherical 
aberration of any combination (p. 75). With reference to this 
he takes occ:asion to remark, that tlic same mode of observa- 



286 ROSSMASSLER'S MICROSCOPIC GLANCE INTO THE 

tion enabled him to judge whether his eyes had remained 
unchanged or not during four or five years, notwithstanding 
the almost daily use of the microscope. He found that dur- 
ing that period the sight of his right eye had become only 
41-lOOOOths =l-244th shorter; and observes, "this was 
satisfactory to myself, and it may also set those persons at 
rest who are fearful lest the use of the microscope should 
injure the eye " — which would be true were the alteration of 
the focal range of the eye the only consequence that can arise 
from the prolonged use of the microscope, especially by 
artificial light, against which we are fully in accord with 
Dr. Hannover, in warning all who have regard to the pre- 
servation of unimpaired visual powers. 

We subjoin the following table of comparative micro- 
metrical measures, given by Dr. Hannover, as it may be useful 
for reference in our pages : — 



Millemetre. 


Paris Lines. 


Vienna Lines. 


Rhenish Lines. 


English Inch. 


1 


0-443296 


0-4555550 


0-458813 


0-0393708 


2-255829 


1 


1-027643 


1-035003 


0-0888138 


2-195149 


0'97310l 


1 


1-0071625 


0-0864248 


2-179538 


0-966181 


0*992888 


1 


0-0858101 


25-39954 


11-25952 


11-57076 


11-65364 


1 



MiKKOSKOPiscnE Blicke in den inneren Bau und das Leben der 
Gewachse, &c. (Microscopical Glance into the Intimate Stnicture and 
Life of Plants. In the form of Popular Lectures.) By E. A. Ross- 
massleb. With 15 mostly coloured lithogi-aphic plates. 118 pp. 8vo. 

The whole is contained in four discourses. In the first the 
author compares the different modes in which natural history, 
or the idea contained in it, is comprehended by different 
classes of minds. To the one it is simply a chandjcr of 
mystery — to another a study — to a third a means of climbing 
to ease and renown — to a fourth a picture-book. To all, he 
says, it ought to be a " beautiful maternal home, to be a 
stranger in which should be regarded, in any one, as a loss 
and shame." He touches upon the question whether natural 
history is a real or merely a humanistic science, and decides 
in favour of tlie latter, seeing that the Jiomo is still a part of 
the kingdom of nature — a convenient, but surely a dangerous 
argument! He lauds the value of the microscope in the 
natural sciences ; and tlj<'n ])ro(ee<ls, in more immediate appli- 



INTIMATE STRUCTURE AND LIFE OF PLANTS. 287 

cation to his subject, to show, that plants consist of cells, 
explaining what is meant by the latter. In the second dis- 
course the theme is continued ; the peculiar forms of cells are 
described, and then the cell-contents: colouring matter, crys- 
tals, nucleus, starch, and the spiral filaments. The ensuing 
chapter discourses about the vessels and their modifications, 
and then adverts to the tissues formed immediately from the 
elementary organs, such as the cuticle with its stomata, hairs, 
setae, and scales ; to the structure of the leaf and ligneous 
stem in the mono- and dicotyledonous plants. The fourth 
chapter embraces the distinction between animals and plants, 
with respect to individuality and their various vital actions ; 
the nutrition of plants and their importance with respect to 
the habitability of the earth ; and lastly, the alternating rela- 
tion between animals and plants. The last discourse treats of 
the root, the changes of matter effected in the interior oi 
plants, the ascent and descent of the nutritive sap, and finally, 
of the parts belonging to fructification, and of fructification itself. 
The illustrations, which are well designed and well executed, 
are copies fi'om the larger figvires employed by the author in 
his lectures. Of course in a work like this the utmost scien- 
tific precision is not to be expected nor many original views 
or facts ; and the mode of treatment requisite in a course ol 
popular lectures necessarily implies that many things must be 
superficially treated ; we have no doubt, however, that the 
little work will obtain numerous readers, who will not tail to 
find in it an interesting and eloquent exposition of the subjects 
of which it professes to treat. 



Principles of thk Anatomy and Physiology ok the Vegetablk 
Cell, By Hugo von Mohl. Translated by Ahthur IIenfrey, F.K.S. 
Loudon, Van Voorst. 

TiiK use of the microscope alone has rendered the production 
of such a work as this possible. It is only a few years ago, if 
the existence of cells in plants was not altogether ignored, that 
their presence was regarded as a matter of little or no conse- 
quence, and vegetal)le physiologists speculated on the func- 
tions of plants, without knowing anything of the agencies 
by which they were produced. Microscopic research has, 
however, shown us that it is in the interior of these minute 
constituents of vegetable tissue that all the functions of plants 
are carried on. Hence we may truly say that the j)rinciples 
of the anatomy and ])hysiology of the vegetable cell are the 
principles of vegetable anatomy antl physiology. 



288 MOHL'S PRINCIPLES OF THE ANATOMY AND 

To few men are we more indebted for the light that has 
been thrown on the functions of plants by the aid of the 
microscope than to Hugo von Mohl. From the time of one 
of his earliest publication on the pores of cellular tissue to 
the present, his contributions to the microscopic anatomy 
of plants have been very constant. To no one, therefore, 
could we listen more attentively on the subject of this work 
than to Hugo von Mohl. Nor is the subject of vegetable 
structure and physiology in so advanced a position as to leave 
little further to be done for its advancement. At present, 
the great proportion of our botanical literature gives indica- 
tions that it is not yet emancipated from the influence of 
theories which were constructed at a time when only the 
most imperfect knowledge of the true structure of plants 
existed. Much of our vegetable physiology has to be re- 
constructed, and it is only by studying the phenomena of 
plant-life, as it presents itself in the simplest conditions, that 
we can expect to understand its more complicated forms. 
It is true that some of the younger botanists have thrown 
off altogether any allegiance to the older school of physio- 
logists, and have determined to accept no theory that 
does not originate in microscopic research ; but in them 
we have only the reaction that was a natural consequence 
of the new aspect which microscopic investigations gave to 
the functions of vegetable life. Amidst the different teachings 
of opposed schools, Hugo von Mohl will be found a safe 
guide for those who are anxious to understand the general 
laws which govern the life of the plant. 

It must not, however, be supposed, that this is a work on 
morphological or systematic botany. The only point of view 
from which it contemplates the plant, is its origin, and that 
of all its parts, and the functions it performs, in the cell. To 
the amateur microscopist, to the animal physiologist, to the 
practitioner of medicine, to the student ambitious of grasping 
the general laAvs which govern the relations of the mineral, 
vegetable, and animal kingdoms, this work will supply those 
facts and principles in which they are each most interested. 
The matter is arranged under two principal heads, the 
anatomical conditions of the cell, and the physiological con- 
<litions of the cell — the cell at rest, and the cell in action. 
Under the first head, we have tlie form, the size, the walls, 
the contents, the relations, and the origin of the cell dis- 
cussed. In tlie latt(!r division, the cell is regarded — 1. As 
an organ of nutrition ; 2. As an organ of propagation; 3. As 
an organ of motion. In going over this wide field, Professor 
von Mohl discusses many controverted points, to some of 



PHYSIOLOGY OF THE VEGETABLE CELL. 289 

which we should have been glad to have drawn attention had 
our space permitted. As he has distinguished himself by his 
researches upon the origin of the vegetable cell, we give an 
extract from this section of his work, relating to the differ- 
ences of opinion which have existed between himself and 
Schleiden : — 

To Sclileiden belongs the merit of discovering free cell-formation and 
the dependence in which the origin of a cell stands to the formation of a 
nucleus ; but he was led by this discovery to the misconception that this 
was the only mode of formation of the cell occurring in nature. In ac- 
cordance with this hypothesis, the cells which were formed in other cells 
would always be much smaller than the parent-cells, and would gradually 
expand until they filled up the cavity of the parent-cells, and their walls 
came into contact. But as the wliole process could not take place in cells 
which contain granular structures, such as chlorophyll or starch granules, 
or the like, without the displacement of these structures, and yet in a cell 
of that kind in which division occurs, all these structures are still present 
after the division, Schleiden invented an hypothesis to explain the circum- 
stance, namely, tliat these structures in the cavity of the parent-cell were 
dissolved outside the secondary cell, and formed anew inside it. But as 
nothing of this process can be observed in nature, it alone suffices to refute 
the doctrine of the universality of free cell-formation. Even when quite 
recenth', in consequence of Kageli's observations, Schleiden (Orundz., 
3rd ed. i. 213) can no longer deny that a division of cells does occur, still 
he is far from acknowledging the universal diffusion of this process, since 
he only refers to the older notion, retracted by Kageli himself, that this 
mode of formatiou occurs in the Phanerogamia or in the special parent- 
cells of the polleu-graius, and altogether ignores the fact that Nageli and 
others have shown this to be the mode of fonnation of all cells except 
those originating in the embryo-sac ; consequently, Schleiden still ascribes 
to free cell-formation an influence on the development of the plant which 
by no means belongs to it. When he states that the cells are developed 
in this way in the embryonal vesicle, this is decidedly false, for all recent 
observations agree in showing that the embryo originates from the germinal 
vesicle by cell-division ; not less incorrect is it, that free cell-formation 
may be traced in jointed hairs, and just as little does it accord with the 
mode of formation of other plants that, as is stated (Grundz., i. 211), 
cells are formed in cells, and the parent-cells absorbed, in the points of 
the roots and shoots of the stem of Cypripediura. Tlie entire representation 
proves that Schleiden has never once observed the division of a cell. 

The first account given by Schleiden {Beitr. zur Phytogenesis, Midler's 
Archiv., 1848) of the process of cell-fonuation, was faulty in many re- 
spects. He altogether overlooked the important circumstance that the 
nitrogenous substances were the originators of the formation of the nuclei 
and the cell, for he believed the granules of protoplasm, which he deno- 
minated mucilage (schhim), to be identical with the granules of gum, and 
thought that the protoplasm might be replaced by sfarch, and go through 
similar metamorphoses ; for he expressly mentions that starch, or the 
granular mucilage replacing it, is present in the pollen-tubes, but tliosc 
substances are soon dissolved, or change into sugar or gum. In the forma- 
tion of a nucleus those little mucilaginous granules were produced in the 
protoplasm, then a few larger granules, and soon afterwards the nuclei 
showed themselves. When a cell was formed, it had at first the form of 
a segment of a s[)herc, the plane side formed by the cytoblast, the convex 
side by the cell-membrane. Originally the cell-membrane was soluble 



290 MOHL'S PRINCIPLES OF THE ANATOMY AND 

in water, but it soon expanded more and more, and acquired greater con- 
sistence ; and its walls, with the exception of the cytoblast, which always 
formed part of the wall, were composed of gelatine. The cell now soon 
became so large, that the cytoblast appeared only as a little body enclosed 
in the lateral wall. The cytoblast might go through the whole vital 
process with a cell, if it were not dissolved and absorbed in cells destined 
to higher development, either in its place, or after it had been cast off like 
an useless member, in the cavity of the cell. — The whole of this account 
of the relation of the nucleus to the cell-membrane is incorrect. The 
nucleus is not connected with the cell-membrane under any circumstances, 
for it is enclosed, with all the rest of the contents of the cell, in the 
primordial utricle. Its position in the newly originating cell is, as appears 
to me, always central, and its form mostly globular ; it does certainly 
often lie upon the wall of the cell subsequent!}', and becomes flattened. 
The distinction which Nageli tries to carry out between central and parietal 
nuclei is not founded in nature. 

Another subject of no less interest to the vegetable physio- 
logist, and to which Schleiden has given a peculiar view, is 
the origin of the embryo in Phanerogamic plants. The 
following is Mohl's account : — 

When the pollen-tube has reached the upper part of the embryo-sac, 
its growth is either immediately arrested, or it becomes elongated a very 
little more, so that its obtuse, somewhat inflated end usually penetrates 
laterally between the embryo-sac and the surrounding cellular layer (pi. 1, 
fig. 14, 15), or, in rare cases (Naixissiis poeticus, according to Hofmeister ; 
Digitalis purpurea, and Campanula Medium^ according to Tulasne), 
introverts the membrane of the embrj'o-sac for a short space. In ex- 
tremely rare cases (in Ckvmia, according to Hofmeister), the pollen-tube 
breaks through the membrane of the embryo-sac, and thus comes imme- 
diately in contact with the germinal vesicles. In the great majority of 
cases, however, as already observed, the pollen-tube is separated from the 
genninal vesicles by the membrane of the embryo-sac, and frequently 
even, the jwint at which the end of the pollen-tube is in contact with the 
embryo-sac, does not correspond exactlj' to the point at which a germinal 
vesicle lies in the inside of the embryo-sac (pi. 1, fig. 15). Therefore 
the only way in which a material effect can be produced by the pollen- 
tube uix)n the germinal vesicle, is by the fluid part of the fovilla tran- 
suding through the membranes of the pollen-tube, the embryo-sac, and 
the germinal vesicle. It cannot be demonstrated that such a transudation 
does take place, but it is in the highest degree probable, since it is incom- 
prehensible how the impregnation of the germinal vesicle could take place 
without it. 

'Jlie pollen-tube begins to decay more oi- less rapidly after it has 
reached the embryo-sac. Its growth is arrested, as before noticed, and 
the fovilla contained in it imdergoes a visible change in its characters, 
accpiiring a granular, half-coagulated aspect ; the pollen-tube itself is by 
this time evidently dead, and disapjiears sooner or later (sometimes, how- 
ever, not until the seed is ripe), apjiarently through absorption. 

On this subject Professor Mohl appends the following 
criticism : — 

Schlciden's theory of the origin of the embryo (Ju'nirje Blicke auf die 
Entwickclnnr/syeHchichtii dcs vctjel. OrganisniiiK, Wiegmann's Archiv., 
1837, 1, 281) — Ueher die. Jillduny dcs Eichevs und KnUtchumi den Km- 



PHYSIOLOGY OF THE VEGETABLE CELL. 2^1 

hryo, Act. acad. nat. Cur., v. xix., p. 1) is completely opposed to the 
foregoing description of this process, since, according to him, the embryo 
is not fonned in the cavity of the embryo-sac, but in the lower end of 
the pollen-tube, which introverts the wall of the embryo-sac, and pene- 
trates more or less deeply into the depression thus formed. If this theory 
Avere true, the germinal vesicle would not be an independent product of 
the ovule, but of the clavate, expanded extremity of the pollen-tube, and 
the suspensor would be the remainder of the latter, running into the 
introverted portion of the embryo-sac. In the whole province of Vege- 
table Physiology, seldom has a theory excited so much curiosity as this 
theory of impregnation. No conviction was more firmly established than 
that the pollen was the impregnating organ ; hence the wonder that it 
should be exactly the reverse. The confusion was great, for the theory 
emanated from a man who showed by his numerous and excellent re- 
searches on the ovule, published at the same time, that he possessed an 
acquaintance with the subject, such as few others had, and who in every 
word expressed the conviction that the matter did occur as he asserted, 
and that a mistake was out of the tjuestion. And others were not want- 
ing to make knoAATi confirmatory observations (Wydler, BihUotli. Univers., 
1838, Oct. ; Ge'le'znoff, Bot. Zeitimf/, 1843, 841), or to support the new 
doctrine on theoretical grounds, and teach it as a settled truth (Endlicher 
and linger, Grundz. der Botanik). It is true that the old notion had its 
defenders, but these maintained the fight a long time with little success. 
8ome who did not know how to use the microscope, thought, nevertheless, 
that an oi)inion might be arrived at here, in which the thing depended 
wholly and solely upon a fact to be determined by the microscoiie, from 
other grounds, but such was utterly without value by itself; others, 
Meyen in particular (Fhyfilologie, iii.), certainly had recourse to the micro- 
scope, but were content with .superficial observations, and thus were not 
very fortunate in their intended refutation of the new theory, for obser- 
vations, in some of which not even the penetration of the pollen-tube 
into the ovule, or the embryo-sac were seen, were not calculated to drive 
an opponent like Schleiden out of the field, and the latter could justly 
interpret some among such discordant observations as Meyen's in his own 
favour. It was Amici again who now for the second time came forward 
with an observation marking an epoch in the theory of impregnation, and, 
by his researches on the impregnation of the Orchideaj (Sidhtft'cundazfone 
delle Orchidee, — Giorn. Bot. Italian, Anno 2), made an end of the new 
theory at one blow. Amici's treatise was soon followed by a confirmation 
of what he had seen by myself {Bot. Zeitimy, 1847, 40.'")), and others ; and 
these were ([uickly siu'cccded by the extensive researches of Hofmeister 
(i>»e Entstehnnrj d. Emhryo d. Phancroyamcn) and of Tulasne (Ann. d. 
Sc. nat. 3 Ser. xii.), which contained a full confirmation of the results 
obtained in the Orchidea', and demonstrated that the im]n-egnative jirocess 
is the same in its essential circumstances throughout a long series of Pha- 
nerogamia, so that this subject may be considered as quite settled in its 
principal features. 

There are some who will probably not agree that this sub- 
ject may be regarded as " quite settled," but we have not spate 
to enter upon the discussion. We will conclude by cordially 
recommending this volume to all who are interested in the 
study of plants, but more especially to those who are anxious 
to gain a view of the grand distinguishing features of vegetable 
life, without entering upon the technical study of their struc- 
ture, forms, and relations. 



( 292 ) 



NOTES AND COREESPONDENCE. 



Mode of Oetermining the Optical Power of a Microscope.— 

I conclude by noticing another method of testing the optical 
power of the instrument, which, although rather troublesome, 
appears to me among the best, permitting us, as it does, to 
ascertain with a great degree of accuracy and certainty, the 
utmost limits of penetrating and separating power possessed 
by a microscope, and hence easily to express numerically its 
optical qualities in the most varied circumstances. 

This method consists simply in subjecting to observation 
under the microscope the dioptric images of certain minute 
objects instead of the objects themselves. These images can 
be diminished at pleasure by withdrawing to a distance from 
the lens the object which forms them ; and hence we hav^e it 
in our power to measure the extreme limits at which the 
object continues to be visible. 

For the formation of the dioptric images achromatic object- 
glasses might be used ; but even where those of the shortest 
focal length are employed, the object whose image it is 
required to form must be placed at a great distance. This 
would cause various difficulties, and only be practicable with 
a microscope placed horizontally — unless, indeed, the object 
selected were very minute, in which case the accurate deter- 
mination of its diameter (from which that of its image must 
be afterwards deduced) would be rendered difficult. 

Small air-bells in a fluid are for this purpose far better. 
I employ by preference a watery solution of powdered gum 
arable, which always contains numbers of such air-bells ori- 
ginating in the air entangled among the particles of the 
powder. The water employed should have stood for a con- 
siderable time freely exposed to the air, or been shaken up 
with the air for some time ; for when we use water which is 
not saturated with air, the bubbles in the fluid gradually 
become smaller, and images formed in them decreasing in 
magnitude, cause errors in the subsequent measurements, as 
we shall actually find to be the case. 

A drop of the fluid must then be placed on a clean glass 
object-slide, and covered with a good clear mica plate, a rlng- 
sha])ed piece of paper being interposed, in oi-der to prevent 
the flattening of the air-bells by pressure. Tlie object-slide 
is then placed under the ol)ject-glass upon the stage of the 



MEMORANDA. 293 

microscope, and an air-bell of suitable size for the formation 
of the images is sought for. All do not give images of the 
same degree of sharpness ; a peculiarity dependent on the fact 
that some air-bells are in contact with the covering-plate, and 
consequently have their spherical form disturbed to some 
extent, or on the presence of small molecules in the fluid 
above or beneath the air-bell, or even in its interior, causing 
some haziness of the image, just as defective polish of a glass 
lens would do. It will, however, be always easy to find some* 
which will form images of the utmost distinctness and purity. 
This may be ascertained in the first instance by holding 
between the mirror and stage some easily recognized object, 
e.g. a piece of paper or the like. The image is always formed 
on the under surface of the air-bell, which inust consequently 
be brought nearer to the object-glass than when it is desired 
to bring its margins into focus. 

The object whose image is to be the subject of examination 
should be placed upon an apparatus, which can be moved 
upwards and downwards in the space between the mirror and 
stage. In some microscopes this can hardly be done, either 
from the space being too limited, or in consequence of the 
drum-like form of the foot of the microscope which quite 
envelops the space. If such microscopes, in place of a mirror, 
be provided with a reflecting prism, the object may be placed 
opposite the side external to the microscope. The instru- 
ments best adapted for the manipulation which we are describ- 
ing are, however, those whose illuminating apparatus consists 
of a mirror and converging lens, which can be shifted up or 
down. The lens being removed from the ring which supports 
it, the object is substituted in its place. The relative magni- 
tudes of object and aii*-bell must be such that the image shall 
be exceedingly minute when the object is tolerably near to 
the stage. On afterwards increasing the distance between 
the object and air-bell, it is not difficult to find the limit at 
which the image (under a given magnifying power) is barely 
visible. 

Of course it is impossible to measure directly the dimen- 
sions of this most minute visible image, for our best micro- 
metric methods will here be found of no avail. Yet their size 

* The follomng example will demonstrate this. I broiight a printed 
page of a book to such a distance from an air-bell that the length of the 
image of the whole page was l-7tli millimetre = about l-]80th of an inch, 
and that of the image of each letter about l-480th millim. = l-12,000th 
of an inch. In spite of their minuteness, these images, formed by reflected 
light, possessed such clearness and sharpness, that under a magnifying 
power of 154 diameters the whole page was without difficulty legible. 

VOL. I, X 



294 MEMORANDA. 

may be estimated with extreme accuracy in the following: 
manner. At the same distance from the air-bell and in place 
of the object used, substitute another body, such as a piece 
of card, of 4 to 5 centimetres := If ths to 2 inches diameter, 
which has been exactly measured. Let this be now again 
measured (by some of the micrometric methods elsewhere 
alluded to *), just as if it were a real object. By dividing the 
real diameter by the apparent diameter, the amount of dimi- 
nution is found ; and this is the same for all objects at a like 
distance from the air-bell. We have, consequently, nothing to 
do, in order to find the amount of diminution of the image of 
the more minute object, but to divide its true diameter by the 
figure expressing the diminishing power. 

For examiple, let the true diameter of the greater object be 
5 centimetres = to 1'969 English inches, and the diameter of 
its image = 32"2 micromillemetres,t = "00127 English inches, 
then the figure expressing the amount of diminution will be 
ctotVt = 1553 very nearly. If now the smaller object have a 
diameter of 175 micromillimetres = "00689 English inches, 
then must its image at the limit of vision be in diameter = 
VsW = "0000044, or about ^^t^^th of an English inch. 
When exact micrometric methods are employed, it is easy in 
this way to estimate the diameter of an image even to millionth 
parts of a millimetre, i. e. to 25,400,000th parts of an inch. 

As for the object suitable for these investigations, it is plain 
that we have an extensive choice. To find the limit of vision 
for bodies of a round or long thread-like form, grains of pearl 
sago, or vegetable bodies, such as mustard-seed or the pollen- 
granules of many plants, hairs of animals, metallic wires, &c., 
may be employed. Small round openings and chinks may 
serve for tlie determination of the visibility of positive images 
of light. In the last case care must of course be taken, by 
means of suitable screens, to shut off all light except what 
passes through the aperture. To determine the defining power, 
metallic wire-gauze is a suitable object, or two holes placed 
near each other in a black metallic plate. The images of such 
objects resemble exactly a doul)le star viewed through a 
telescope (kijker). The bodies may likewise be placed in 
different circumstances in order to ascertain the influence of 
tliese upon the limits of vision. Thus we may use as an object 
a very thin glass capillary-tube placed in water, and compare 
it with tender organ ic-tul)es and vessels, which may also be 

* See translation from Ifrt MikrosJcoo]) in Monthly Journal of Medical 
ficience, -lime lH.5ii, p. 4.53, et seq, 

t 'i'lie micromillinietre is equal 1-lOOOth millimetres = "0000394 Eng- 
lisli inclies. Hoe Monthly JonrnaJ, Juno 1852, p. 456. 



MEMORANDA. 295 

seen in water, but whose limit of visibility is of course far 
more circumscribed than that of absolutely opaque objects. 

In fact this method admits of innumerable variations, and is 
consequently of most extensive application. Besides, when 
proper precautions are taken, it gives results perfectly sure 
and comparable. Especial care is however requisite in the mode 
of illumination. For it is certain, that when the field has a 
clear white ground, the contrast causes minute opaque bodies 
(z. e. objects which are dark by transmitted light) to continue 
visible, which against a grayish or light-blue back-ground 
could not be seen. Hence it is by no means indifferent to 
receive on the mirror light from a white cloud, from a dull 
overcast, or clear blue sky. Artificial light cannot be used in 
these experiments, for the image of the flame becomes dimi- 
nished like the object, and hence a clear field of view is not to 
be obtained. The observations must consequently be made 
by daylight ; and whenever comparable results are sought for, 
the mirror should always be directed to the clear, blue, cloud- 
less sky — this being a distinct atmospheric condition to which 
others in similar circumstances may refer in conducting the 
same experiment. The mode of ascertaining the limit of 
vision, with a given amount of illumination, may be gathered 
from different examples in the body of this work. It will 
likewise be found that for all such observations, even when 
the highest magnifying powers are employed, the Jlat mirror 
is perfectly sufficient, since in the image in the field of view 
formed by the air-bell, all the rays proceeding from the mirror 
are united and constitute an object of considerable luminous 
intensity. — Professor Harting, Utrecht. — Monthly Journal 
of Medical Science. 

On a Bffew Animalcule. — The animalcules described in the 
following pages were found in great numbers in the bottom 
of a small vessel or " aquarium," in which colonies of Plnma- 
tella, Melicerta, and Limnias had been kept. Of all the 
forms which can with certainty be referred to tlie animal king- 
dom, there are few which at first sight are so little likely to 
be recognized as animals as those about to bo described. 

If the reader will imagine a bag made of some soft exten- 
sible material, so thin as to be transparent like glass, so soft 
as to yield readily by extension when subjected to internal 
pressure, and so small as to be microscopic ; this bag, fdled 
with particles of sand, shells of Diatomaccfr, portions of Algae 
or Desmidiea?, and with fragments of variously coloured cot- 
ton, woollen, and linen fibres, will give a picture of the 
animal ; to complete which it is only necessary to add a few 

X 2 



296 MEMORANDA. 

loose strings to the bag, to represent the variable radiant pro- 
cesses which it possesses around the mouth. 

When I first saw these curious creatures they attracted but 
little attention, as I supposed they were merely excrementitious 
masses due to some of the aquatic animals living in the vessel 
where they occurred. A more careful examination showed 
that they moved spontaneously, and even with some degree of 
rapidity ; and that this motion was due to radiant, branching, 
and variable feelers, or " rhizopods," which were thrown out 
near one extremity. By attaching these feelers to various 
objects the animal was enabled by means of them to pull 
itself along, or to change its position at will. 

The most common form in which these creatures occur is 
that of a pear-shaped mass having the feelers attached to the 
larger end, while the other end appears almost always to be 
pushed out, and rendered acute by the presence of several long 
diatomaceous shells which the animals have swallowed. 

Another curious set of forms appears to be produced by the 
process of spontaneous fission or self-division. 

The partial fission, or a budding from the sides, when com- 
bined with the distortion produced by the internal pressure of 
the various articles swallowed, gives rise to a variety of com- 
plex and extraordinary forms. Some of these appear as if 
several pear-shaped individuals were about to be produced by 
a budding from the sides of the parent, but it is also certain 
that some at least of these sac-like projections are only tem- 
porary extensions produced by internal pressure. This was 
decided beyond a doubt by a series of continued observations 
upon single individuals. 

The substance of which these animals are composed is much 
like that composing the bodies of the various species of 
Amoeba, being soft, colourless, elastic, and extensible. It is 
probably without any true integument, and is coloured yellow 
by tincture of iodine. It appears to resist internal pressure 
with considerable force, and it is but rarely that it appears to 
be completely broken through by any of the matters, however 
hard, which are contained within it. I have, however, found 
some individuals which had voluntarily impaled themselves 
upon long fibres which were distinctly seen projecting through 
tlie animalcules at each end, and these animals were seen 
moving freely along, from one end of the fibre to the other, 
without appearing to experience any inconvenience from the 
perforation. 1 have occasionally found them attached in this 
way to filaments of Conferva and Draparnaldia, which were 
still alive at one extremity. The traces of internal structure 
or organization are exceedingly slight. Occasionally, when a 



MEMORANDA. 297 

portion of the body is left vacant, some slender thread-like 
lines may be seen in the interior. 

In many individuals 1 have seen the protrusion from the 
mouth of transparent, rounded masses, which rapidly suc- 
ceeded each other until they were heaped up about the mouth 
like a set of soap-bubbles, and were then as rapidly drawn in 
again. The more common appearance, however, is that where 
the mouth is suiTounded by a considerable number of slender, 
colourless, radiant, branching, and retractile feelers, precisely 
like the rhizopods belonging to the marine Foraminifera or 
Polythalamia. When fully extended, these often exceed in 
length that of the body of the animal. They change rapidly 
from simple to branched, or vice versa, and are at one moment 
seen in a state of tension, and then wrinkled and collapsed, or 
changed into various rounded processes, which can be wholly 
retracted. These feelers, tentacles, variable processes, or 
rhizopods are not like the pseudopods of Amoeba, mere pro- 
trusions of the surface, nor are they thrown out as in that 
genus, from all parts of the animal. They, on the contrary, 
resemble those of a Diffiugia, in being confined to the vicinity 
of the mouth ; but they are much more slender and more 
repeatedly branched than in any Diffiugia which I Lave seen. 
By means of these organs the animals pull themselves along, 
when lying upon their side, and they also creep by means of 
them, with the mouth downwards, moving onwards with a 
slow gliding motion like that of a Diffiugia. 

Besides the heterogeneous collection of matters which these 
animals swallow, and which can be seen distinctly with all the 
forms and colours through the transparent exterior, there is 
also, in most specimens, a considerable number of small 
globules scattered without order, whose nature is very doubt- 
ful, for as yet there is no proof whether they are ova, oil 
drops, or something else. 

When these creatures have swallowed bits of fibres which 
have been dyed of various colours, the reds, blues, scarlets, &c 
of these filaments may be distinctly perceived through the 
sides of the animal ; but the spectacle becomes still more 
curious when seen by polarized light, when the particles of 
quartz, &c., contained within these creatures also display their 
gorgeous tints. 

When these creatures are dried upon glass, and then 
mounted in balsam, their forms are not greatly altered, and 
their contents become still more distinctly visible. It seems 
scarcely probable that these animals have so little discrimina- 
tion as to swallow for food all the strange mixtures of organic 
and inorganic bodies whicli are found within them. It is pos- 



298 MEMORANDA. 

sible, however, that adhering to these grains of sand, fibres of 
wool, &c., there may be nutritive matters deposited from the 
water, which may be removed by the process of digestion, as 
the soft contents of the shells of Diatomaceae also appear to 
be. This view is supported by the fact, that on the appli- 
cation of tincture of iodine to these animals, a distinct blue 
colour was often seen all over the surface of many of the 
grains of sand in their stomach. The starch giving rise to 
this colour, was doubtless derived from bits of boiled beans 
and potatoes which had occasionally been introduced into the 
aquarium as food for other animalcules. Another fact which 
appears to show that the sand, &c., is not swallowed merely to 
increase the absorbing surface, as Dujardin suggests may be 
the case in Amoeba, is that these particles of sand are not 
retained for any great length of time, but in company with 
the empty shells of Diatomaceae, and other remains of their 
food, they are, after a while, thrown out at the mouth, which 
appears to be the only aperture for their reception and dis- 
charge. There appears to be no reason to doubt that the 
cavity into which all these bodies are received is a true 
stomach, and they therefore manifestly cannot be considered 
as poly gastric animals. As to the position of these creatures 
in the system of Zoology, it is evident that they belong to the 
Infusorial Rhizopoda of Dujardin, and connect the genus 
Amoeba with Difflucjia, agreeing with the first in the soft body 
without shell, but differing in having true feelers or rhizopods 
confined to the anterior portion of their body, and by not 
throwing pseudopods from other parts. From Difflugia and 
the whole family of Arcellina, these forms are distinguished 
by having no lorica or shell. They are, however, closely 
allied to the Arcellina, and are very nearly what some of the 
species of this group would be, if deprived of their rigid ex- 
ternal coverings. 

In order to give to these curious beings at least a temporary 
name and j)laco, I propose to found for their reception a new 
genus named and characterized as follows, viz. : — 

Pamphagus, nov. gen. 

Animals of the class of Rhizopoda (intermediate between 
Amoeba and Arcellina) without shell or lorica, and composed of 
a soft, colourless matter, easily extended by internal pressure, 
but not sj)ontaneously protruded into pseudopods. Feelers 
or rhizopods, slender, numerous, radiant, branching, and con- 
fined to the neighbonrliood of the mouth. 

Species 1. Pampliagus mutabilis. — This species, which is 
the only one now known, is sufficiently described above. Its 



MEMORANDA. 299 

habitat is probably the bottom of small pools and streams of 
fresh water, as it was found in vast numbers in an aquarium 
supplied from such places in the vicinity of West Point, It 
will probably be found to be a common form ; and as it pre- 
sents the conditions of animal life in almost the lowest degree 
of simplicity, and can be preserved and studied with great 
ease, it will well reward the attention of microscopists. I 
have thousands of these animals now living in mid-winter, 
and with a little care they rnay probably be kept until the 
return of warm weather, when other interesting facts may 
possibly be added to the observations here recorded. J. W. 
Bailey. — American Journal of Science and Arts, vol. xv. 

On certain peculiar Structures in the Placenta of the 
Bitch. — The placenta in this animal forms a circular band 
with distinctly-marked margins, on each of which, at and near 
the conclusion of gestation, is an olive-green, almost black, 
line, having the appearance of coagulated blood. On placing 
a portion of this dark matter under the microscope, and ex- 
amining it with powers varying from 200 to 600 diameters, it 
was seen to contain numerous unaltered blood discs ; cells 
containing a bluish-green, and other cells filled with a deep 
red, colouring matter. The cells containing the red-colouring 
matter were almost opaque, and bore a striking resemblance 
to the nodules of colouring matter so constantly seen in the 
spleens of animals. The bluish-green colouring matter con- 
tained in the other cells varied in tint, from brilliant blue to 
bluish green, and light green in different cells. Both kinds of 
colouring matter were insoluble in water, but soluble in 
acetic acid and solution of caustic potass. These colouring 
matters were evidently enclosed in distinct cells, of which the 
membrane could be readily distinguished. The cells varied 
in form ; were rounded, oval, sometimes agglutinated in masses, 
and often very irregular. The cells varied in diameter, from 
1-2400 to 1-343 of an inch ; some of those containing the red- 
colouring matter being as small as 1-3430 of an inch. 

In addition to these colour-containing cells, an immense 
multitude of minute crystals, of a light reddish tint, were 
diffused over the field. They had the form of elongated, 
flattened prisms, either with distinctly truncated or irregular 
extremities. The colour varied from distinct red, with a play 
of prismatic colours, to colourless. The more minute of the 
crystals showed little colour, as might be expected, since the 
red corpuscles of tlie blood appear scarcely coloured when 
viewed with a high power under a strong light. These cr^'s- 
tals varied in length, from 1-171 to 1-1828 of an inch, and 
in breadth, from 1-2400 to 1-1 5,000th of an inch. 



300 



MEMORANDA. 



With regard to the origin of these colouring matters, it 
seems sufficiently evident that they are produced by a meta- 
morphosis of the hoematin of the blood-discs; and it is by no 
means improbable that the crystals consist of nothing more 
than the altered colouring matter of effused and stagnant 
blood. Similar crystals have been described by Kolliker in 
specimens of effused blood, in the blood of the portal Aein, 
and in the spleen ; and by Dr. Parkes and others in putrid 
blood. They are interesting as exhibiting the crystallization 
of a purely organic principle within the living and healthy 
body. — Philip B. Ayres, M.D., London. 



isj.e 




^=:=. 







Fig. 1 represents cells from the margin of the placenta of the bitch, 
containing blue and reddish-brown colouring matter, often in granules ; 
but these have neither the diameter nor appearance of blood discs. 400 
diameters. 

Fig. 2. Crystals contained in the tissues of the margin of the placenta 
of the bitcl), but not enclosed in cells, having a yellowish or reddish tint 
under the microscope. 400 diameters. 

Fig. 3. Vibriones from putrescent urine, showing the transverse lines 
which indicate spontaneous divisions. 600 diameters. 

All the figures were drawn with the camera lucida. 

Vibriones. — Whenever an animal fluid, or water containing 
a portion of animal substance, is allowed to stand aside for a 
few days, until putrefaction commences, a multitude of minute, 
active animalcules, of an elongated cylindrical form, may be 
seen moving througli it, which have received the name of 
Vibriones. 1 hcse animalcules are so minute and transparent, 
that no internal structure can be seen with a power of GOO or 
900 diameters ; the highest powers with which I have had the 
opportunity of observing them. They have been viewed by 



MEMORANDA. 301 

some naturalists as the efficient agents or excitors of putre- 
faction, in the same sense that the yeast-plant is the excitor of 
fermentation in saccharine fluids ; but this opinion is not as 
yet decisively determined, although the experiments of Pro- 
fessor Schultze, and, so far as I have been able to observe, their 
universal presence in putrescent fluids, seem to corroborate 
it. Considerable difference is seen in the length of different 
individuals, some being as long as 1-600 of an inch, while 
the shortest is 1-6000, the average length being 1-4000 to 
1-2000. Although the variation in length is so great, all 
of them retain nearly the same transverse diameter, which 
is under 1-12,000 of an inch. This circumstance, together 
with the immense rapidity of their formation in a putrefying 
fluid, points to a fissiparous mode of reproduction ; but this, 
so far as I have been able to ascertain, has not been described. 
In examining some putrescent urine last year, in which there 
were a large number of these animalcules, I observed that, 
while the shortest of the vibriones were in active motion, the 
longer imes were comparatively quiescent ; and that these ex- 
hibited, according to their length, from one to six transverse 
lines, indicating the points of separation in the reproductive 
process. Those of moderate length, presenting only one or 
two transverse lines, were rather active, and often bent at an 
angle at the transverse line, which presented the appearance 
of separation into two distinct individuals, and the character 
of the movements appeared such as to favour the separation. 
Those with from three to six transverse lines were, for the 
most part, quiescent. I imagined, although from their ex- 
cessive minuteness and transparency this was not plainly and 
unequivocally discernible, that there were indentations of the 
extremities of the transverse lines by which constrictions were 
produced, which by their increase would finally effect a com- 
plete transverse division of the animal (Fig. 3). These animal- 
cules deserve a careful examination by those microscopists who 
possess higher powers, on account of their intimate connexion 
with the process of putrefaction. — Philip B. Avres, M.D., 
London. 

Finder. — Observing in the last number of the Quarterly 
Journal, an ingenious Finder for microscopists, suggested by 
Mr. Tyrrell, I send a plan I have used some time for the 
same purpose, adapted for minute objects and high powers. 
On the thinnest writing paper, in a space one inch long and 
half an inch deep, 1 rule about 30 divisions to the inch, 
vertically, leaving on the top space to designate the numbers 
of the lines ; this slip so ruled, I fasten with Rotham's India 



302 



MEMOKANDA. 



Rubber Paste on the left side of the sliding object plate (fig. 
a), with the bottom of the lines close to the lower ledge used 
for the support of the object slide, &c. ; I also rule another 
paper one and half inch long, and one inch deep, with hori- 
zontal lines also about thirty to an inch, numbering them on 
each side as above, and paste the paper so ruled on the bottom 
of the brass piece of the stage (b) on which the slide moves. 




so that the slide will pass over the paper, and cutting out a 
half circle in the paper for the hole in the under plate, leaving 
lines on each side the said hole. When I wish to fix the 
finding of any minute object, I adjust the moveable stage 
exactly square, by a mark made for the purpose on the upper 
and lower parts (slips of paper pasted on each will do), and find 
the object by moving the slide plate and slip of glass on which 
the object is placed, till the latter is in the centre of the eye- 
piece, and then observe the number of the line the left hand 
end of the glass slip touches on the vertical scale, and also the 
number of the line the bottom of the sliding plate rests on in 
the horizontal scale — say No. 7 the first, and 15 the latter — I 
then mark on the right hand end of slide or glass slip 7 and 
15, and when so placed again the object is easily found. It 
is very requisite, however, tlie stage should ahoays be adjusted 
to the mark before the left hand end of the slide or slip and 
the bottom of the sliding plate are placed according to the 
numbers. The above scales are easily made, and affixed to 
every microscope with a sliding plate, or may be engraved on 
the plate at a small expense. By placing these scales at 
right angles to each other on a plain stage, the same end 
may be attained, and in a simpler manner. — E. G. Wright, 
Hereford. 

The FiiMler. — I take the liberty of submitting to your 
notice a modification of Mr. Tyrrell's useful instrument the 



MEMORANDA. 



303 



" Finder," adapted for use on the plain stages of foreign or 
other microscopes. It gives at a glance, as you will see, the 
latitude and loiu/itude, so to speak, of the object sought, and 
saves an infinity of time and trouble in hunting over uneven 
surfaces — such, for instance, as fragments of flint containing 
Xanthidia, where ordinarily the focal adjustments are con- 
stantly at work. 

Take a thin, flat piece of boxwood, one inch and a 
quarter broad, and four inches long. Along 
the top of this fasten another piece, 
thicker than your slides, a quarter of 
an inch broad, and also four inches long. 
Next, to the left side glue a piece of the 
same thickness and one inch square, and 
upon this a scale is to be ruled, divided 
into fortieths of an inch, each mark repre- 
senting a letter of the alphabet. Now 
remove the middle inch from the three 
that remain uncovered of the flat piece, as 
far as the upper shoulder. Next take a 
very thin slip of ivory, about a quarter of 
an inch broad, and two inches and three 
quarters long, point one of its ends, and 
bore a hole for a pivot five-eighths of an 
inch from the apex ; at the other end mark 
an inch scale into fortieths, and iminher 
the divisions by fives. This slip is to turn 
on its pivot near the right hand edge of 
the raised portion to the left, in such a 
manner that its own scale may mark the 
longitude in numbers of any object in the 
field, while its pointed end will give the latitude on the 
lettered scale of the boxwood. 

The exact position of the object (+) in the accompanying 
sketch is L. 22. The letters A, F, K, P, U, are used to every 
long fifth line ; the shorts indicate the intervening letters. — 
Thomas Edward Amyot, Diss, Norfolk. 

The Finder. — Since reading the description of Mr. Tyr- 
rell's " Finder," given in the last number of the Microscopical 
Journal, I have adopted a modification of it which is far more 
simple, and appears to possess several advantages over a sepa- 
rate scale. My plan is to make a fine scratch, either with a 
writing diamond or the broken end of a three-square file, near 
the edge of the slide, directly opposite to the specimen of 
which it is desired to preserve the exact locality, so as to be 
able to find it again at any future moment. Tlie method of 



A^ K p ^, 

o 



304 MEMORANDA. 

using this is the same as in the original, with this exception, 
that, instead of being bothered with counting the intermediate 
divisions of the scale, the edge of the slide being brought into 
the field, it may be moved horizontally until the scratch be 
seen, and by using the vertical movement the object itself is 
soon discovered. Of course, several objects may be thus de- 
noted in the same slide, as both edges may be marked with 
several lines each, and which may be so faint as not to disfi- 
gure the slide in appearance. In recording on the label each 
individual thus indexed, either end of the name may have the 
number of the mark placed to correspond with that edge of 
the glass which contains it. 

To prepare the slide thus is extremely simple and easy. 
In the first place a fine notch must be cut on the inner edge 
and near the middle of the cross bar at the bottom of the stage 
plate, and against which the glass slide rests when pressed in 
its place by the " clip :" let this notch be brought into the 
centre of the field and the vertical movement alone be made 
use of. For the horizontal, the slide itself must be moved 
upon the stage plate until the desired specimen be found: then 
bring the notch upon the bar again into the field, to see that 
the two, the object and the notch, may both be in the centre 
of the field, using the vertical movement on the sliding plate 
of the stage. If the slide be held firmly by the clip (I use a 
piece of cork in preference to a metallic spring), the plate 
may be slid off and then marked with the greatest accuracy. 

I have objects which may thus be readily found with a 
quarter-inch object glass, and when once carefully marked the 
slides are available at all times or with any instrument, and 
are far more convenient in every respect, as well as less un- 
sightly, than when the discs are disfigured by rings scratched 
or painted on the surface. — W. K. Bridgman, Noi^wicli. 

Professor Widdcll's Binocular Microscope. — 1 our April 
number, I perceive, contains some notice of my binocular 
microscope, &c., from Silliman's Journal. I have completed 
two elaborate models of this instrument, both of which work 
to admiration. I enclose you a printed slip from the April 
number of the New Orleans ' Monthly Medical Register,' from 
which you may get an idea of my latest modification : — 

Professor EiddcU, the original inventor of the binocular niieroscopc, 
exhibited and explained a simplification of that important instiuinont, by 
which, at an cxjicnsc not necessarily exceeding thirty or forty dollars, it 
is ])racticablc, in existing compound microscopes of the ordinary forms, to 
rejilacc the brass tube carryinii; the ocular and objective, by an efficient 
arrangement for binocular vision. To accomjilish an cciual division of the 
pencil of light immediately behind the objective, and to effect its distribu- 
tion to each ocular, only two glass prisms need be used. They must be 
of such form, that the faces, at which the light is imrnergent and emergent, 



MEMORANDA. 305 

shall form equal angles witli the face on which the internal reflection 
occurs. The chromatic disjiersion is a minimum, and really nothing, 
when these angles are each near eighty-seven degrees. This foim is 
theoretically preferahle. In the instnimeut constructed, and shown bj' 
Professor Eiddell, the Frencli rectangular prisms, such as sold by most 
opticians, were used, in which the equal angles alluded to are forty-five 
degrees. The long sides of these, which are the reflecting surfaces, face 
each other, and, while the edges next the objective are in contact, the upper 
edges are adjustable, so as to vary at pleasure the inclination of the prisms 
to each other. In its transit through these prisms, the light is reflected 
internally, and imdergoes two refractions which are almost mutuallj' com- 
pensatory. The result is satisfactory. To produce orthoscopic binocular 
vision, simple, not erecting eye- pieces, are required. 

While making microscopical dissections, it is convenient 
to have the free use of both hands. This convenience 1 com- 
mand by connecting the fine focus movement with a delicate 
piston-rod, which is moveable by breathing through a flexible 
tube. This plan works admirably. — J. L. Riddell, New 
Orleans, May 25, 1853. 

I/ocalities of Microscopic Plants and Animals. — For the 

information of microscopical observers resident in and near 
the metropolis, allow me to state that the following species, 
in addition to commoner ones which I do not think it neces- 
sary to specify, may be found in the freshwater and brackish 
ditches in the parish of Milton-next-Gravesend : — 



Surirella striatiila 

Gemma 

Aneurea squamata 

striata 

Nitschia reversa 

Closterium 

Ciallionella nummuloides 
Cosmarium crenatum 

imdulatum 

Sj-nedra valens 

• biceps 

acicularis 

radians 

lunaris 



Synedra Ulna 
Amphora oralis 
Cymbella Ehrenbergii 
Cyclotella Kutzingiaha 
Gomphonema olivaceum 
Bacillaria paradoxa 
Leucophrys patula 
Coleps hirtus 
Nassula elegans 
Schizonema 
Euplotes Charon 

truncatus 

Pleurosigma Hippocampus 
elongatum. 



On the north side of the Serpentine, Hyde Park, especially 
near the bridge, may be found : — 

Cymbella maculata I Amphora ovalis 

Gomphonema cristatum I Cocconeis placentula 

Scenedesmus quadricauda I Uvella hyalina 

• obliquus GallionoUa nummuloides 

Ankistrodcsmus falcatus Euastrum elegans 

Pediastrum Hcptactys Pyxidula operculata. 

Cocconema lanceolatum | J- M. \\. 

JMicroscoiie Camera. — In the last number of this Journal, 
I suggested an arrangement (fig. 12) for taking photographs 
of microscopic objects. Since then I have perfected this ; 



30(3 



MEMORANDA. 



and as it is very compact, steady, and ever ready for imme- 
diate use, I think it may be found advantageous to those who 
are constantly employins: photography in its application to the 
microscope. A tube, A, screws into the flange of a camera 
which has a range of twenty -four inches ; the front of this 
tube is closed, and into it screws the object-glass, B. Over 
A slides another tube, C : this is closed by a plate, D, which 
extends beyond the upper and lower circumference of C, and 
carries a small tube, E, on which the mirror, F, is adjusted. 
To the upjier part of D the fine adjustment G is attached; 
this consists of a spring wire coil acting on an inner tube 
to which the stage-plate, H, is fixed, and is regulated by a 
graduated head, K, acting on a fine screw likewise attached 
to the stage-plate, after the manner of Oberhauser's micro- 
scopes. An index, L, is fixed opposite the graduated head, 
K. The stage and clamp slides vertically on H, and by 
sliding this up or down, and the glass object-slide horizon- 
tally, the requisite amount of movement is obtained to bring 
the object into the field, Tlie object being brought into view, 
the imago is roughly adjusted on the focussing-glass by sliding 









^H^^BS^S^^^^^^^^^SI 



C on A ; the focussing is completed by aid of the fine ad- 
justment, G, K, and allowance then made for the amount of 
non-coincidence between the chemical and visual foci of the 
object-glass. The difference in each glass employed should 
be ascertained by experiment in the first instance, and then 
noted. By employing a finely-ground focussing-glass greased 
with oil, this arrangement forms an agreeable method of 
viewing microscopical objects with both eyes, and is less 
fatiguing. As a very large field is presented to the observer, 
tliis arrangement might be advantageously employed for class 
demonstration. — Samuel Highley, Jan., Fleet Street. 



( 307 )W 



PROCEEDINGS OF SOCIETIES. 



Royal Institution of Great Britain. 

A Lecture on the Identity of Structure of Plants and Animals 
By Thomas H. Huxley, Esq., F.R.S. 

The Lecturer commenced by referring to his endeavours last year 
to shew that the distinction between living creatures and those 
which do not live, consists in the fact, that while the latter tend to 
remain as they are, unless the operation of some external cause effect 
a change in their condition, the former have no such inertia, but 
pass spontaneously through a definite succession of states — different 
in kind and order of succession, for different species, but always 
identical in the members of the same species. 

There is, however, another character of living bodies — Organiza- 
tion; wliich is usually supposed to be their most striking peculiarity, 
as contrasted with beings which do not live : and it was to the 
essential nature of organization that the Lecturer on the present 
occasion desired to direct attention. 

An organized body does not necessarily possess organs in tiie 
physiological sense — parts, that is, which discharge some function 
necessary to the maintenance of the whole. Neither the germ nor 
the lowest animals and plants possess organs in this sense, and yet 
they are organized. 

It is not mere external form, again, which constitutes organiza- 
tion. On the table there was a lead-tree (as it is called) which, a 
mere product of crystallization, possessed the complicated and 
graceful form of a delicate Fern. If a section were made of one of 
the leaflets of this tree, it would be found to possess a structure 
optically and chemically homogeneous throughout. 

Make a section of any youag portion of a true plant, and fhe 
result would be very different. It would be found to be neither 
chemically nor optically homogeneous, but to be composed of small 
definite masses containing a large quantity of nitrogen, imbedded 
in a homogeneons matrix having a very different chemical comjio- 
sition — containing in fact abundance of a peculiar substance — Cel- 
lulose. 

The nitrogeneons bodies may be more or less solid or vesicular — 
and they may or may not be distinguished into a central mass 
{nuclewi of Authors) and a peripheral portion ( Contents, Primor- 
dial utricle of Authors) — on account of the confusion in the existing 
nomenclature, the Lecturer proposed the term Emloplasts for 
them. 

The cellulose matrix, though at first unquestionably a homoge- 
neous continuous substance, readily breaks up into definite portions 



308 PROO .EDINGS OF SOCIETIES. 

surrounding each Eridoplast, — and these portions have therefore 
conveniently, thoughc as the Lecturer considered, erroneously, been 
considered to be independent entities under the name of Cells : — 
these, by their union, and by the excretion of a hypothetical inter- 
cellular substance, being supposed to build up the matrix. On the 
other hand, the Lecturer endeavoured to shew tliat the existence of 
separate cells is purely imaginary, and that the possibility of break- 
ing up the tissue of a plant into such bodies, depends simply upon 
the mode in which certain chemical and physical diiferences have 
arisen in the primarily homogeneous matrix, to which, in contra- 
distinction to the Endoplast, he proposed to give the name oi Peri- 
plast or Periplastic Substance. 

In all young animal tissues the structure is essentially the same, 
consisting of a homogeneous periplastic substance with imbedded 
Endoplasts (^nuclei of Authors) as the Lecturer illustrated by refer- 
ence to diagrams of young Cartilage, Connective Tissue, Muscle, 
Epithelium, &c. &c. ; and he therefore drew the conclusion that 
the common structural character of living bodies as opposed to those 
which do not live, is the existence in the former of a local physico- 
chemical differentiation ; while the latter are physically and chemi- 
cally homogeneous throughout. 

These facts, in their general outlines, have been well known since 
the promulgation, in 1838, of the celebrated Cell-theory of Schwann. 
Admitting to the fullest extent the service which this theory had 
done in Anatomy and Physiology, the Lecturer endeavoured to 
shew that it was nevertheless infected by a fundamental error, 
which had introduced confusion into all later attempts to compare 
the vegetable with the animal tissues. This error arose from the 
circumstance that when Schwann wrote, the primordial utricle in 
the vegetable-cell was unknown. Schwann, therefore, who started 
in his comparison of Animal with Vegetable Tissues from the struc- 
ture of Cartilage, supposed that the corpuscle of the cartilage cavity 
was homologous with the " nucleus " of the vegetable cell, and that 
therefore all bodies in animal tissues, homologous with the cartilage 
corpuscles, were " nuclei." The latter conclusion is a necessary 
result of the premises, and therefore the Lecturer stated that he 
had carefully re-examined the structure of Cartilage, in order to 
determine whicli of its elements corresponded with the primordial 
utricle of the plant — the important missing structure of which 
Schwann had given no account — working subsequently from Carti- 
lage to the different tissues with which it may be traced into direct 
or indirect continuity, and thus ascertaining the same point for 
them. 

Tiie general result of these investigations may be thus expressed : 
— I?iall the animal tissues the so-called nucleus (Endoplast) is the 
homologue of the primordial utricle {with nucleus and contents') 
(Endoplast) of the Plant, the other histological elements being 
invariably modifications of the periplastic substance. 

Upon 'this view we find that all the discrepancies which had 
appeared to exist between the Animal and Vegetable Structures 



PROCEEDINGS OF SOCIETIES. 309 

disappear, and it becomes easy to trace the absolute identity of plan 
in the two, — tlie differences between them being produced merely 
by the nature and form of the deposits in, or modifications of, the 
periplastic substance. 

Thus in the Plant, the Endoplast of the young tissue becomes a 
" primordial utricle," in which a central mass, the " nucleus," may 
or may not arise ; persisting for a longer or for a shorter time, it 
may grow, divide and subdivide, but it never (?) becomes metamor- 
phosed into any kind of tissue. 

The periplastic substance follows to some extent the changes of 
the Endoplast, inasmuch as it generally, though not always, grows in 
when the latter has divided, so as to separate the two newly formed 
portions from one another ; but it must be carefully borne in mind, 
though it is a point which has been greatly overlooked, that it 
undergoes its own peculiar metamorphoses quite independently of the 
endoplast. — This the Lecturer illustrated by the striking case of the 
Sphagnum leaf, in which the peculiarly thickened cells can be shewn 
to acquire their thickening fibre after the total disappearance of the 
primordial utricle, — and he further quoted M. von Mold's observa- 
tions as to the early disappearance of the primordial utricle in woody 
cells in general, — in confirmation of the same views. 

Now these metamorphoses of the periplastic substance are two- 
fold : 1, Chemical ; 2, Morphological. 

The Chemical changes may consist in the conversion of the 
cellulose into xylogen, &c., &c., or in the deposit of salts, silica, &c. 
in the periplastic substance. Again, the periplastic substance 
around each Endoplast may remain of one chemical composition, or 
it may be different in the outer part (so-called intercellular sub- 
stance) from what it is in the inner (so-called cell-wall). 

As to Morpiiological changes in the periplastic substance, they 
consist either in the development of cavities in its substance — 
vacuolation (development of so-called intercellular passages) or in 
fibrillation (spiral fibres, &c.). 

It is precisely the same in the Animal. 

The Endoplast may here become differentiated into a nucleus and 
a primordial utricle (as sometimes in Cartilage), or more usually it 
does not — one or two small solid particles merely arising or existing 
from tlie first, as the so-called " nucleoli;''' — it persists for a longer 
or shorter time ; it divides and subdivides, but it never (except per- 
haps in the case of the spermatozoa and the thread-cells of Medusae, 
&c ) becomes metamorphosed into any tissue. 

The periplastic substance, on tlie other hand, undergoes qinte 
independent modifications. By chemical cliange or deposit it ac- 
quires Horn, Collagen, Cliondrin, Syntonin, Fats, Calcareous Salts, 
according as it becomes Epithelium, Comiective Tissue, Cartilage, 
Muscle, Nerve, or Bone, and in some cases the chemical change 
in the immediate neighbourhood of the endoi)last is different from 
that which has taken place exteriorly, — so that the one portion 
becomes separable from the other by chemical or mechanical means ; 
— whence, for instance, has arisen the assumption of distinct walls 

VOL. I. Y 



310 PROCEEDINGS OF SOCIETIES. 

for the bone-lacunae and cartilage- cavities ; of cell-contents and of 
intercellular substance as distinct histological elements. 

The Morphological changes in the periplastic substance of the 
animal, again, are of the same nature as in the plant : — Vacuolation 
and Fibrillation (by which latter term is understood, not only the 
actual breaking up of a tissue in definite lines, but the tendency to 
do so) — Vacuolation of the periplastic substance is seen to its 
greatest extent in the "Areolar" connective tissue; — Fibrillation 
in tendons, fibro-cartilages, and muscles. 

In both Plants and Animals, then, there is one histological ele- 
ment, the Endoplast, which does nothing but grow and vegetatively 
repeat itself ; the other element, the periplastic substance, being the 
subject of all the chemical and morphological metamorphoses, in 
consequence of which specific Tissues arise. The differences be- 
tween the two kingdoms are, mainly, 1. That in the Plant the 
Endoplast grows, and, as the primordial utricle, attains a large 
comparative size ; — while in the Animal the Endoplast remains 
small, the principal bulk of its tissues being formed by the peri- 
plastic substance ; and, 2, in the nature of the chemical changes 
which take place in the periplastic substance in each case. This 
distinction, however, does not always hold good, the Ascidians 
furnishing examples of animals whose periplastic substance contains 
cellulose. 

" The Plant, then, is an animal confined in a wooden case, and 
Nature, like Sycorax, holds thousands of ' delicate Ariels ' impri- 
soned within every Oak. She is jealous of letting us know this, and, 
among the higher and more conspicuous forms of Plants, reveals 
it only by such obscure manifestations as the shrinking of the Sen- 
sitive Plant, the sudden clasp of the Dionoea, or, still more slightly, 
by the phenomena of the Cyclosis. But among the immense variety 
of creatures which belong to the invisible world, she allows more 
liberty to her Dryads ; and the Protococci, the Volvox, and indeed 
all the Algae, are, during one period of their existence, as active 
as animals of a like grade in the scale. True, they are doomed 
eventually to shut themselves up within their wooden cages and 
remain quit-scent, but in this respect they are no worse off than 
the Polype, or the Oyster even." 

In conclusion, the Lecturer stated his opinion that the Cell- 
theory of Schwann consists of two portions of very unequal value, 
the one anatomical, the other physiological. So far as it was 
based upon an ultimate analysis of living beings and was an ex- 
haustive expression of their anatomy, so far will it take its place 
among the great advances in Science. But its value is purely 
anatomical, and the attempts which have been made by its author, 
and by others, to base upon it some explanation of the Physiolo- 
gical phenomena of livinp; beings by the assumption of Cell-force, 
Metabolic-force, &c. &c., cannot be said to be much more philo- 
sophical than the old notions of " the actions of the vessels," of 
which physiologists have lately taken so much pains to rid them- 
selves. 



PROCEEDINGS OF SOCIETIES. 311 

" The living body has often, and justly, been called, ' the House 
we live in ;' — suppose that one, ignorant of the mode in which a 
house is built, were to pull it to pieces, and find it to be composed 
of bricks and mortar, — would it be very pliilosophical on his part 
to suppose that the house was built by brick-force ? But this is 
just wiiat has been done with the human body. — We have broken 
it up into ' cells,' and now we account for its genesis by cell-force." 

[T. H. H.] 



Microscopical Society. 

April 27, 1853. George Jackson, Esq., President, in the 
Chair. — A communication from Professor Wheatstone on ' The 
Binocular Microscope, and on Stereoscopic Pictures of Microscopic 
Objects ' was made by Dr. Lankester. (See Transactions in present 
Number of Journal.) 

3Iay 25, 1853. The President in the Chair. — A communica- 
tion was made by Mr. "Wenham on ' The Construction of Binocular 
Microscopes.' He exhibited an instrument constructed under his 
direction by Messrs. Smith and Beck (whose promptness to execute 
the work he acknowledged) consisting of one object glass and two 
eye-pieces, in which the object was presented stereoscopically to the 
eye. This arrangement was effected by allowing the object to be 
refracted through two glass prisms so as to reach separately the two 
eye-pieces. 

Mr. Shadbolt read a paper on ' Some new forms of Diatomaceee 
from Port Natal.' Having alluded to the confused state of the 
nomenclature of the Foreign species of this family, and expressed a 
hope that the work now in course of publication by Messrs. Smith 
and Beck on the British species would lay the foundation for a more 
correct system, the author proceeded to describe particularly the 
novelties in a gathering from Port Natal, which contained no less 
than fifty-five species, of which twenty at least were new, including 
five of the genus Triceratium, two of Pleurosigma, and three of a 
new genus Bacteriastrum. From the nature of the forms it was 
concluded that the locality must have been subject to marine influ- 
ence, and probably contiguous to some river. 

June 22, 1853. The President in the Chair. — Mr. Legg com- 
municated to the Society some ' Observations on the Examination 
of Sponge Sand, with Remarks on Collecting, Mounting, and 
Viewing Foraminiferse.' Having observed that there was some 
degree of uniformity in the magnitude of several of the species of 
shells, the author assumed that by sifting the sand through sieves of 
different de|^rees of fineness much labour might be spared, and he 
therefore procured some pieces of wire gauze, varying from 10 to 
100 wires to the inch, the result of which was fully equal to his ex- 
pectation, many of tiie larger kinds being thus brouglit together '\n 
considerable abundance, and the mass cleared of l9-20ths of very 
fine material, containing a very small proportion of shells; this 



312 PROCEEDINGS OF SOCIETIES. 

last-mentioned material was afterwards submitted to a process of 
washing by placing a quantity of the sand in a dish, covering it 
with water to the depth of half an inch, and gently agitating it so 
as to form little eddies, the minute shells were then found to be 
collected in distinct channels of a whiter aspect than the other parts, 
and were readily removed by means of a camel's-hair pencil. 

The author then noticed the occurrence of Foraminiferous shells 
on the Sniallmouth Sand, near Weymouth, in considerable abund- 
ance, by having remarked that the surface of the sand was distinctly 
marked by little ridges extending many yards in length, and parallel 
to the edge of the water ; these portions, upon examination, proved 
to be minute shells. He also mentioned the occurrence of Fora- 
miniferae on the surface of the mud in Shoreham Harbour, and in 
the ouze from the Oyster-beds. From these evidences the author 
concluded that the surface alone of sand or mud banks should be 
collected with a view to finding these organisms. 

The paper concluded with some practical remarks on mounting 
and viewing Foraminiferae, in which the author recommended the 
annular condenser of Mr. Shadbolt, or the parabolic reflector of 
Mr. Wenham, as the best means of developing such of these objects 
as are of a transparent texture. 

A paper was read from Mr. Eainey on a new mode of illumi- 
nating objects. 

The President announced that arrangements had been made w ith 
the Editors of the Microscopical Journal, by which the members 
would be entitled to that publication without further payment as 
heretofore. 



DESCRIPTION OF PLATE X. 

Fig. 

1. Lateral aspect of the Faujasina. Magnified 30 diameters. 

2. Superficial section of the flat base of the shell. Mag. 60 diameters. 

3. Horizontal section parallel to the last, across the points bb, in fig. 1. 

Mag. 60 diameters. 

4. Horizontal section across the points c c in fig. 1. Mag. 60 diameters. 
!). Vertical section across the points d d in fig. 1. Mag. 60 diameters. 
6. Superficial section from the oblique side of the shell. Mag. 80 dia- 
meters. 



AOI.. I. 



air. 



''^iJpm^.yw.%1 



Rg. 




^, t\T'< 



^ !&^^\ '"^ )_ 









V^ 



,1 <^S^ 




FCq.5. 



Kg 6. 




^' ^ h.' r^ t 



w,cwa)i«D3™ aoi, T^iifanWirt. 



KnI * WsM lap 



mwr< JowmChO W- 




DESCRIPTION OF PLATE V. 

Fig. 

1. Lougitudinal section of superior canine tooth, exhibiting contour mark- 

ings — their general arrangement. Slightli/ magnified. 

2. Transverse section of canine tooth, decalcified and picked abroad, so 

as to exhibit the annular (stratified) arrangement. Mag. 15 dia- 
meters. 

3. Transverse section of canine tooth, exhibiting globular patch, and the 

various forms of interglobular spaces. Mag. 200 diani. 

4. Innermost film of calcifying dentine, removed from the inner surface 

of the pulp cavit}' of a molar, exhibiting calcified globules, and 
interglobular uncalcified dentine, dried up. The specimen is 
mounted in balsam. Mag. 200 diam. 

5. Similar to the last, from a bicuspid. This specimen exhibits the 

calcification of tubeless dentine. Mag. 200. 



DESCRIPTION OF PLATE VI. 

1 Represents a section of a portion of the scalp made perpendicular to 

the surface and parallel to the hairs, 
a, a^ Cg . . . ffg are muscles attached to the hair-follicles b h h . . . . 
just below the sebaceous glands c c c . . . . and extending up to- 
wards the epidermis, of which d is the corneous and e the mucous 
layer ; //is adipose tissue. 

2 Exhibits on a larger scale the upper attachment of the two muscles a 

and Oj of fig. 1, a being the upper end of ai, and h that of Og ; c is 
the corneous and d the mucous layer of the epidermis. 

3 Shows the insertion of the muscle a, of fig. 1 into its hair-follicle, a' 

being the lower end of o, : the hair and follicle are cut across very 
obliquely ; h is the hair slightly tilted out of the inner root-sheath 
c, and dimly seen below through the transparent root-sheath in its 
course dowTiwards ; d is the outer root-sheath, e the " structureless 
layer of the hair -follicle," / the circular coat of KoUiker, g the 
longitudinal layer, /; is part of a sebaceous follicle, i is some of 
the fibrous tissue of the dermis. 

4 Represents the upper termination of a muscle h c with the surrounding 

fibrous tissue of the scalp gelatinized by acetic acid ; ab is the free 
surface deprived of epithelium. 

6 Exhibits characteristic nuclei, highly magnified, from a muscle con- 
nected with a hair-follicle of the pubes. 

C) Shows the ajipcarance of a portion of a muscular fasciculus, from the 
areola mammae, after the addition of acetic acid ; the rod-shaped 
nuclei are seen to lie in an indistinctlj' fibrous stroma. 



\()i.. 



JlLc^Jefj/mJ. % V 












1 



Jipm^ Jov/rn/. VI. 




./A -^ -^ 



^ 



J-^. 




yi 



ffi dion,' 







^^ 



.., R95. !j / 

SeSdiait,'! 1/ / 



f- 



^ 



0$aicffit> * 






TRANSACTIONS 



MICPiOSCOPICAL SOCIETY 



LONDON. 



NEW SEKIES. 



VOLUME r. 



LONDON: 

SAMUEL HIGHLEY, 32, FLEET STREET. 

LS53. 



LONDON : PUINIED BY W. CLOWES AND SONS, STAMFORD STREET. 



INDEX TO TRANSACTIONS. 

VOLUME I. 



Aloe verrucosa, raphides in, 21. 
Amphistegina, 87. 

Asteridia, in Algse, Rev. W. Smith 
on, 68. 



B. 



Beale, Dr. L., analysis of raphides of 
Cactus enneagonus, 25. 

Binocular microscope, Prof. Wheat- 
stone, 99. 

Brachionus, 3. 

Busk, G., on the structure and de- 
velopment of Volvox glohator and 
its relations to other vmicellular 
plants, 31. 

„ some observations on the 
structure of the starch granule, 58. 



C. 



Cactus enneagonus, Quekett on ra- 
phides of, 20. 

„ senilis, Quekett on raphides 
of, 22. 

Chara vulgaris, 21. 

Cladopkora glomerata, 21. 

Cocconema lanceolatum, 21. 

Cordylophora lacustris, 21. 

Cyst, membranous, containing a crys- 
tal of oxalate of lime, on the olfac- 
tory nerve of a horse, J. B. Simonds 
on, 26. 



D. 



Delves, Joseph, on the application of 
photography to the representation 
of microscopic objects, 57. 

Diatomaceous earth found in the 
Island of MrJl, Prof. W. Gregory, 
92. 



E. 



Elaagnus angustifolia, raphides in, 22, 
Epithemia lurgiaa, 95. 
Eunotia Triodon, 95. 

„ Peiitodon, 95. 

,, Fabra, 95. 



P. 



Faujasina, minute structure of, by 
Prof. Williamson, 87. 

Floscularia, vibrating membranes in, 
3. 

Fresh-water Algae, stellate bodies oc- 
curring in the cells of, Rev.W. Smith 
on, 68. 



Gosse, P. H., on water vascular sys- 
tem in Notommata aurita, 5. 

Gregory, Prof. W., on Diatomaceous 
earth foimd in the Island of Mull, 
92. 



H. 



Huxley, T. H., on Lacinularia so- 
cialis, 1. 

Hijdrodictyon utriculatum, amyla- 
ceous corpuscles of, 67. 



K. 

KoUiker on division of the yolk in 
Megalotrocha, 11. 



Lacinularia socialis, anatomy and 
physiology of, by T. II. Huxley, 
F.U.S., I. 

Leydig, Anatomic u. Entwick.-gescli 
d. Lacinularia socialis, &c., 2, 8, 12. 

Lynghyajloccosa, 71. 



M. 



Meqalolrocha, 1, 12. 

Meliccrtc, 3. 

Merulius lachrymans, 74. 

Mesostomum, 7. 

Mesocarpns scalaris, 71. 

Mummery, I. U., on the development 

of Tiibiilaria iiidivisa, 28. 
Mull earth, 95. 



Index to Trail fiactions. 



N. 



Naviculacese, 93. 

Notovimata aurita, teeth of, 4. 

„ water vascular sys- 

tem in, P. H. Gosse on, 5. 
Nonionina, 87. 

N. 

Opiintia, raphides in, 21. 



Philodiita, 17. 

Photography, on the application of, to 
the representation of microscopic 
objects, by J. Delves, 57. 

Polyzoa and Rotifera, analogy be- 
tween, 16. 

Potatoe, amylum grains of, 62. 

Pohjstoniiila crispa, 87. 



Q. 



Quekett, on the structure of the ra- 
phides of Cactus eimeayonus, 20. 

,, on the presence of a Fungus 
and of masses of ciystalline matter 
in the interior of a living oak tree, 
72. 



R. 



Raphides, Quekett on, of various 

plants, 20. 
Rhubarb, raphides in, 21, 



Scilla maritima, I'aphides of, 21. 
Simonds, J. H., on a meiubranous cell 

or cyst upon the olfactory nerve of 

a horse, coiitaining a large crystal 

of oxalate of lime, 26. 
Smith, IJev. W., on the Asteridiw or 

stellate bodies occurring in the cells 

of Fresh-water Algae, 68. 



Spharoplea oispa, 21. 

Sphcerosira Vohw.r, ,32, 39. 

Sponi/iUa Jlnviatilis, 2 1 . 

Starch, granule, observations on the 

structure of, by G. Busk, 58. 
Stephanoceros, 4. 
Stirirella ovata, 21. 
Synedra fasciculata, 21. 



Tous le mois, starch of, 65, 66. 
Truncatulina tuherculata, 87. 
Tubularia indivisa, development of 

by I. R. Mummery, 28. 
Turbellaria, 16. 

U. 

Udekem, on the water vascular sys- 
tem of Lacinularia, 6. 



Volvox globator, Busk, G., on the struc- 
ture and development of, 31. 

,, further elucidations of 

the structiu-e of, by Prof. W. C. Wil- 
liamson, 45. 

V. aureus, 40. 

V. steUatus, 40. 



W. 



W illiamson, Prof. W. C, further eluci- 
dations of the structure of Volvox 
ylohator, 45. 

Williamson, Prof. W. C., on the mi- 
nute structure of Faujasiua, 

Wheatstoue, Prof., on the binocular 
microscope and stereoscopic pic- 
tures of microscopic objects, 9'J. 



Z'/gnenia {piudraium, 70. 
,, quininum, 70. 



TRAXSACTIOXS 

OF THE 

MICROSCOPICAL SOCIETY 

OF 

LONDON. 



Lacinularia socialis. a Contribution to the Anatomy and 
Physiology of the Rotifera. By T. H. Huxley, Esq., 
F.R.S., Assist-Surgeon R.N. (Read Dec. 31, 1851.) 

The leaves of the Ceratophyllum, which abounds in the river 
Medway, a little above Faileigh Bridge, are beset with small 
transparent, gelatinous-looking, globular bodies, about l-5th 
of an inch in diameter. These are aggregations of a very 
singular and beautiful Rotifer, the Lacinularia socialis of 
Ehrenberg. On account of their relatively large size, their 
transparency, and their fixity, they present especial advantages 
for microscopic observation ; and I therefore gladly availed 
myself of a short stay in that part of the country to inquire 
somewhat minutely into their structure, in the hope of being 
able to throw some light on the many doubtful or disputed 
points of the organization of the class to which they belong. 

We are told by Ehrenberg (' Infusions-Thierchen,' p. 403) 
that Lacinularia socialis was discovered and described 
anonymously in Berlin in 1 753. Miiller bestowed upon it 
the name of Vorticella socialis, which was changed by 
Schweigger to Lacinularia in 1820. Previously to tlie time 
of Ehrenberg the genus appears to have I)ecome confounded 
with Meyalotroclia ; and indeed Dujardin very reasonably, 
as it seems, altogether denies the propriety of tlieir separa- 
tion. The extreme resemblance of the two forms is fidmittcd 
by Ehrenberg himself ; but he considers the attachment of 
the ova of Meyalotrocha by a fdament to the body — a circum- 
stance which does not obtain in Lacinularia — and the exist- 
ence of a gelatinous investment in tlie latter which is not 
found in the former, to be sufticient grounds of distiiu tlon. 

Tlie matter is not one of much importance, but I call 
attention to the close alliance between Mcyalofrocha aiul 
Lacinularia for a reason which will appear in the sequel. 

The globular aggregations of which I have spoken are not 

VOL. I. h 



2 Huxley on Laciaularia socialis. 

ramified animals like the freshwater Polyzoa, to which, at 
first sight, they have no small resemblance, but may be truly 
called compound animals, since each of the Lacinularice is a 
separate individual, which at one time swam about freely by 
itself,* which has voluntarily united itself with its fellows, 
and has taken its share in throwing out the gelatinous sub- 
stance which connects them into a whole. 

Each Lacinularia (PI. T. fig. 1) has an elongated conical 
body, whose outer extremity is considerably the wider, and 
whose inner smaller end is truncated, and serves as a sucker 
or means of attachment to the stem on which the whole mass 
is seated ; the outer third or fourth of the body contains the 
viscera, nothing but the muscular cords extending into the 
inner narrow elongated part of the animal. During con- 
traction the latter portion is thrown into sharp folds, while 
the visceral portion presents only three or four faint transverse 
constrictions. 

When the Rotifer is in a state of expansion and activity, 
its outer extremity is terminated by a large horseshoe-shaped 
wheel-organ, or " trochal disc " (figs. 2, S), connected with 
the body by a narrowed neck. When contracted and at rest, 
the whole of this apparatus is drawn in, and the body takes 
on a more pyriform appearance (fig. 5). 

The mouth lies in the notch of the trochal disc (fig. 4 d) ; the 
anus is placed on the opposite side, at the lower part of the 
visceral portion of the animal (Ji). 

Anatomy of LacimLl aria. — I will now proceed to describe 
the various organs of the animal more minutely. 

The " troclial disc " is, as 1 have said, wide and horseshoe- 
shaped. It is seen in profile at figs. 1 and 2 ; from above 
at fig. 3. Its edges are richly beset with large cilia, which 
present a very beautiful wheel-like movement. 

Ehrenberg says that the ciliary organ is " as in Megalo- 
trocha^^ and in this he describes the disc as having a simple 
ciliated edge. I have not examined Mef/alotrocha, but I can 
say most decidedly that such is not the structure of La- 
cinularia.\ 

In fact, the edge of the disc has a considerable thickness, 
and presents two always distinct margins — an upper (^ji) and 

* Or ratlicr had tlic ]iower of swimminp; about freely ; for it does not 
a]ipcar that tlie young Jjaciniilariiv ever do leave the gelatinous envelope 
of the parent mass, urdess aggregated together. 

■i- Leydig (Zur Anatoniie und Entwickelungs-geschichtc der Lacinu- 
laria socialis — Siehold and Kcillikev's Zoitschrift for February, 1852) says 
that "an elevated ridge runs along the lower surface of the wheel organ, 
not far from and parallel to its margin, whence there is a double edge and 
a groove, in which alone ciliary motion is observed." 



Huxley 0)i Ladmilaria socialis. 3 

a lower (p'), of which the former is the thicker and extends 
beyond the latter. 

The large cilia are entirely confined to the upper margin, 
and, seated upon it, they form a continuous horseshoe-shaped 
band, which, upon the oral side, passes entirely above the 
mouth (fig. 4). The lower margin (j/) is smaller and less 
defined than the upper, its cilia are fine and small, not more 
than l-4th the size of those of the upper margin. On the oral 
side this lower band of cilia forms a V-shaped loop (fig. 4), 
which constitutes the lower and lateral margins of the oral 
aperture. About the middle of this margin, on each side, 
there is a small prominence, from which a lateral ciliated 
arch runs upwards into the buccal cavity, and, below, becomes 
lost in the cilia of the pharynx. 

The aperture of the mouth therefore lies between the 
upper and lower ciliary bands. It is vertically elongated, 
and leads into a buccal cavity with two lateral pouches, which 
give it an obcordate form ; these lateral pouches contain the 
lateral ciliated arches. A narrow pharynx leads horizontally 
backwards from the lower part of the buccal cavity, and 
becomes suddenly widened to enclose the pharyngeal bulb in 
which the teeth are set. Where the buccal cavity meets the 
pharynx, a sharp line of demarcation exists (fig. 2). In 31eli- 
certa two curbed lines are seen in a corresponding position, and 
evidently indicate two folds (PI. II. fig. 26), projecting upwards 
into the oesophagus. In Brachionns these folds are stronger 
(fig. 31), while in Steplianoceros and Floscularia this partition 
between the oesophagus and what may be called the crop is 
still more marked. From the inner margin of the aperture 
in the partition two delicate membranes hang down into the 
cavity of the crop, which have a wavy motion, and it is to them 
I think that what Mr. Gosse describes as an appearance of 
*' water constantly percolating into the alimentary canal" is 
due. Dujardin had already noticed (1. c, p. 98) these 
"vibrating membranes" in Floscularia (' Infusoires,' p. 611). 

Between the pharyngeal bulb and the mouth there lies on 
each side of the pharynx a clear, yellowish, horny-looking 
mass (/), which sometimes appears merely cordate, at others 
more or less completely composed of two lobes. A similar 
structure exists in Brachionns and Alclircrta. I believe its 
function is to give strength to tlie tkiicate walls of the 
pharynx, and that it is therefore to be considered as a pait ol 
the horny skeleton.* 

* I.eydijc (loc. cit.) calls these hodics sacs, aiul considers tlicni to be 
salivary elands. 

h2 



4 IIuxLEY on Lacimilaria socialis. 

The general nature of the pharyngeal bulb and of its 
movements has been so often described that it is needless 
for me to refer to the subject here. With regard to the teeth, 
however, what I have seen is considerably at variance with 
the accounts of both Ehrenberg and Dujardin ; the former 
calls the teeth of Lacimilaria " reihenzahnigen," that is, 
having a stirnip-like frame, with many teeth set upon it ; 
and the latter, in his general definition of the " Melicertiens," 
under whicli head he places Lacinularia, has " machoires en 
etrier" ('Hist. Nat. des Infusoires,' p. 612).* 

As I liave seen it (fig. 6), the armature of the pharyngeal 
bulb in this species — as in Stepliannceros — is composed of 
four separate pieces. Two of these (which form the incus 
of Mr. Gosse) are elongated triangular prisms,! applied 
together by their flat inner faces ; the upper faces are rather 
concave, while the outer faces are convex, and upon these 
the two other pieces (the mallei of Mr. Gosse) are articulated. 
These last are elongated — concave internally, convex ex- 
ternally — and present two clear spaces in their interior; 
from their inner surface a thin curved plate projects inwards. 
At its anterior extremity this plate is brownish, and divided 
into five or six hard teeth, with slightly enlarged extremities. 
Posteriorly the divisions become less and less distinct, and 
the plate takes quite the appearance of the rest of the piece. 

This is essentially the same structure as that of the teeth 
of Notovimata, descriljed by Mr. Dalrymple (' Phil. Trans,' 
1849), and by Mr. Gosse (on the Anatomy of Notommata 
aurita, Mic. Trans. 1851), and very different from the true 
" stirrup-shapod " armature. 

A narrow oesophagus passes directly downwards from the 
])ostorior part of tlie cavity of the pharyngeal bulb, through 
the neck of the animal to the body, where it opens into the 
wide alimentary canal. 

This is divided into three portions by an upper, a middle, 
and a lower constriction. 

The two upper parts are often not very distinctly divided. 
A wide oval or pyriform sac, whose wall contains many nu- 
cleated cells, opens into the upper portion on each side. This 
is the " pancreatic" sac of Ehrenberg.^ 

The middle dilatation frequently gives origin to several short 
cellular cocca. 

The lowest dilatation is globular, and has also several cel- 

* Lcydig also finds Ehrcnbcrg's figures "untrue to nature." 
f Not (Ifscriheil by Lcydig. 

% According to Leydig there are four of these bodies, two smaller and two 
lar'cr, and they do not oi'cn into the alimentary canal. — Loc. cit., i». 463. 



Hl'xley on Lacinularia sociah's. 5 

lular coeca projecting from its outer surface. Within it is 
clothed with very long cilia. 

The intestine is short and wide, and comparatively delicate ; 
it bends suddenly upwards on the side opposite the mouth, 
and terminates in a cleft of the integument, whose whole extent 
it did not seem to me to occupy. (Fig. 1 k) 

The IVater Vascular System. — This system is thus loosely 
and confusedly alluded to — I cannot call it described — by 
Professor Ehrenberg:* — "The vascular system consists of 
transverse circular canals in the body, a vascular network at 
the base of the wheel-organ, with perhaps a broad circular 
canal at this part, and of trembling gill-like bodies" — (loc. cit., 
p. 403). The vascular system is so obvious, f that it is diffi- 
cult to understand how it can have been thus blurred over. 

The reader will bear in mind that the two bands v/hich run 
up from the cloaca in many Rotifera, and are usually con- 
nected at their extremity with a " contractile vesicle," Avhile 
they give attachment in their length to the " trembling gill- 
like organs" of Ehrenberg, are considered by the latter to be 
the testes. He says that " the trembling organs " appear to 
be within the sac in Hydatina, outside it in Notommata. 

Von Siebold (' Vergleichende Anatomic ') first pointed out 
that a vessel runs up in each of these bands, and that the 
" trembling organs " are short branches of these vessels, eacli 
of which contains a vibrating ciliary band (Flimmer-lappchen), 
to which the trembling appearance is due. According to Von 
Siebold each of these vibrating bodies indicates an opening in 
the vessel. 

Oskar Schmidt (' Versuch einer Darstellung d. Organisation 
d. Riiderthiere' — Erichsons Archiv, 1846) asserts that the 
ends of the water-vessels are closed, and that the vibrating 
body is within them. 

Dalrymple (loc. cit.) saw no testes in the lateral bands of 
Notommata, and considers that the " tags" (the " trembling 
organs " of Ehrenberg) are externally ciliated at their extre- 
mities. 

Mr. Gosse (' Microscopical Transactions,' 1851) describes 
the water-vascular system in Notommata aurita, and states 
that the " tags" of Ehrenberg are really j)yriform sacs; but 
he seems not to have distinguished the contained cilium, at 
least his description is ambiguous. " When trembling mode- 
rately they arc seen to be little oval bags attached to the tor- 
tuous vessel by a neck and sac at the other end. A spiral 

* " I can thus affirm, that what Ehrcnljerg dcscrilws as vessels in 
Lacijiuhiria arc in fact not vessels at all." — l.vydif], loc. cit., p. 403. 
t " Hehr aus-gepragt," Leydig, p. 4G5. 



6 Huxley on Lacinularia socialis. 

vessel, closed at the extremity, runs through most of its length, 
which maintains a wavy motion" — p. 98.* 

The following is what I have seen in Lacinularia : — There 
is no contractile sac opening into the cloaca as in other genera, 
but two very delicate vessels, about l-4000th of an inch in dia- 
meter, clear and colourless (fig. 3 m), arise by a common origin 
upon the dorsal side of the intestine. Whether they open into 
this, or have a distinct external duct, I cannot say. 

The vessels separate, and one runs up on each side of the 
body towards its oral side (fig. 2). Arrived at the level of 
the pharyngeal bulb, each vessel divides into three branches 
(fig. 3) ; one passes over the pharynx and in front of the pha- 
ryngeal bulb, and unites with its fellow of the opposite side, 
while the other two pass, one inwards and the other outwards, 
in the space between the two layers of the trochal disc, and 
there terminate as cceca. Besides these there sometimes 
seemed to be another branch, just below the pancreatic sacs. 

A vibratile body was contained in each of the ccecal 
branches ; and there was one on each side in the transverse 
connecting branch. Two more were contained in each lateral 
main trunk, one opposite the pancreatic sacs, and one lower 
down, making in all five on each side. 

* 'M. Udekem (Annales des Sciences, 1851) has given a very elaborate, 
but I think not altogetlior correct, account of the water- vascular system 
of Lacinularia. He says that a vascular net-work exists at the base of the 
lobes of the whecl-orgau ; that these unite into gland-like ganglia (my 
" vacuolar thickenings," in the margin of the disc infra) ; that from these, 
vessels i)r()ceed to the central glands (vacuolar substance, in which the 
"band" of the water-vascular system terminates, milii), from which three 
great vessels are given off. Of these, one "passes above the digestive 
tube, and anastomoses with its fellow from the opposite ganglion ; the 
second presents the sam3 disposition as the first, but is placed below the 
digestive tulx; ; the third passes directly downiwards, skirting the digestive 
tube." M. Udekem ibund it " impossible to trace it any further, but 
considers that it becomes lost on the digestive canal and ovaries." He, 
therefore, has missed the external opening of the water-vascular system. 

What I have seen and described as "vacuolar thickenings" in the 
peduncle, are descril)ed by M. Udekem as vascular ganglia, from which 
anastomosing vessels proceed. 

As M. Udekem's instrument does not seem to have been good enough 
to define the vibratile cilium — for he speaks only of a " vibratile or trem- 
bling movement" — I venture to think that he has been misled in describing 
these threads and vacuolar thickenings as I'urming any part of the true 
vascular system, 

Leydig's opinion of M. Udekem's results is, I find, much the same as 
my own. He says, "Critically considered, then, we (ind that lldekem's 
vascular system in Lacinularia is compounded of a lUTUtitiide (if the most 
heterogeneous parts of the animal — of strucluies which belong to the most 
difierent systems of organs, without one being a true blood-vessel." — L. c, 
p. 405. 



Huxley on Lacinularia socialis. 7 

Each of these bodies was a long cilium (1-1 400 th of an inch), 
attached by one extremity to the side of the vessel, and by the 
other vibrating; with a quick undulatory motion in its cavity 
(fig. 8). As Sicbold remarks, it gives rise to an appearance 
singularly like that of a flickering flame, 

I paiticularly endeavoured to find any appearance of an 
opening near the vibratile cilium, but never succeeded, and 
several times I thought I could distinctly observe that no such 
aperture existed. Animals that have been kept for some days 
in a limited amount of water are especially fit for these re- 
searches. Tiiey seem to become, in a manner, dropsical, and 
the water-vessels partake in the general dilatation. 

The " band " (fig. 7) which accompanies the vessel ap- 
peared to me to consist merely of contractile substance, and to 
serve as a mechanical support to the vessel. It terminates 
above, in a mass of similar substance, containing vacuolap, 
attached to the upper plate of the trochal disc. I shall refer 
to this and similar structures below. 

I examined these structures so frequently that I have no 
doubt that the account I have given is essentially accurate,* 
and I am strengthened in this opinion by the account and 
figure of the corresponding vessels in Mesostumum given by 
Dr. Max Schulze, in his very beautiful monograph upon the 
Turbellaria (Beitrage zur Naturgeschichte d. Turbellarien). 
Through these the transition to the richly ciliated water- 
vessels of the Naidae, »Scc., is easy enough. 

Vacuolar Thickenings. — (figs. 2, 3 r). Under this head I in- 
clude a series of structures of, as I believe, precisely similar 
nature, which, on Professor Ehrenberg's principles of interpre- 
tation, have done duty as ganglia, testes, «Scc., in short, have 
taken the place of any organ that happened to be missing. 

In various parts of the body the parietes have become 
locally thickened, and the prominences thus formed have 

* Leydig's careful description coincides in all essential points with tliat 
given a'oove. He ])articularly notices the fitness of Jjaoinularia) that have 
been imprisoned for some time, for the examination of llie water-vascular 
system. 

The only discrepancy of importance in Leydig's account is — firstly, that 
he considers wliat L have called the " vacuolar tliiekcning on each side of 
the pharyngeal mass," and what IChrenberg calls a nervous centre, to bo 
formed by convolutions of the water-vessel itself; and secimdly, that ho 
describes a cloacal vesicle as in other liotifera. i looked particularly for 
such a vesicle, but could never see any ; in some cases, indeed, I could 
trace tlie water-vessels distinct I'rom one another, close to the anus. 

]5cyond these particular cases, however, I will by no means venture to 
contradict so accurate an observer as M. liCydig. 

Lcydig docs not seem to have noticed the transverse anastomosing vessel 
over the pharynx. 



8 Huxley on Laciniilan'a socialis. 

developed many clear spaces, or vacuolap — a histological pro- 
cess of very common occurrence among the lower invertebrata. 

I\ow these thickenings are especially obvious in two 
localities — 1st, in the prolongation of the body below the 
visceral cavity ;* and 2ndly, in the trochal disc. 

Of the former thickenings, the four uppermost are pro- 
moted by Professor Ehrenberg to be testes, for no other 
reason, apparently, than that, having missed the true water- 
vascular system with its bands, he knew not where else to 
find what he calls a male organ. 

Again, the thickenings (figs. 2, 3 ?•) in the trochal disc are 
mostly towards its lower surface and at its inferior margin ; 
they are generally four or five on each side, and are connected 
by branched filaments with that body on each side of the 
pharyngeal mass in which the band of the water-vascular 
system terminates. 

According to Professor Ehrenberg these are all ganglia, 
and the two yellowish bilobed or cordate bodies on each side 
of the pharynx are " comparable to a brain ! " 

JVeiTous System and Organs of Sensef[ — On the oral side 

* Leydig (loc. cit., p. 467-8) reirards the central vacuolar mass at the 
root of the tail as a peculiar gland, from which he says a duct runs down- 
wards to terminate at the extremity of the taih The purpose of this 
organ is to secrete the gelatinous envelope. I must confess that I saw no 
grounds for this interpretation. The estremitj' of the tail ahvaj's seemed 
to me to present a ciliated hemispherical cavity, closed above. 

t Leydig (1. c, p. 457 et seq.) criticises at length, and altogether re- 
pudiates, the mythical nerves and ganglions which Professor Ehrenberg 
has ascribed to Laciiiularia. He does not appear to have seen either the 
ciliated cavity, or the body Avhich I still venture to think is the only true 
ganglion ; but describes a very jieculiar nervous system, consisting of — 

1. A ganglion behind the i)harynx, composed of four bipolar cells, with 
their processes. 

2. A gan'jlion at the beginning of the caudal prolongation, similarly 
composed of four larger ganglionic cells and their processes. 

'I'be latter cells are what I have described as vacuolar thickenings ; I 
could find no dillcrence whatever between them and the thickenings in the 
di.sc, which Leydig allows to be mere thickenings. 

Tlie former were not observed by me. I have not been able to repeat 
my investigations upon this ] oint, as I hope to do ; for the ])resent I must 
offer as arguments against Leydig's interpretation of the nature of tlie 
structures which lie observed — 

1st. Tliat the l)ody which I describe as a ganglion is perfectly similar 
in a])pcarancc to the mass on which the eye-spots of Bra.hionus are seated. 

2n(l. Tliat if sucli an arrangement of the nervous system as tliat which 
Leydig describes exists, llic I'otifera are ver^' widely diflercnt from their 
congeners, and, indeed, from all known animals. 

Leydig himself, liowever, says, — "'I'hat these cells, with their radiating 
processes, are ganglion-globules and nerves, is a conclusion drawn simply 
from the liistological constitution of tlie parts, and from the impossibility 
of making anything else out of them, \inless, indeed, organs arc to be 
named according to our mere will and pleasure." — L, c, p. 451). 



Huxley on Lacinularia socialis. 9 

of the neck of the animal, or rather upon the under surface of 
the trochal disc, just where it joins the neck, and therefore 
behind and below the mouth, there is a small hemispherical 
cavity (fig. 4c») (about l-1400th of an inch in diameter), which 
seems to have a thickened wall, and is richly ciliated within. 
Below this sac, but in contact with it by its upper edge, is a 
bilobed homogeneous mass (figs. 2 and 4 n) (about l-800th 
of an inch in diameter), resembling in appearance the ganglion 
of Brachionus, and running into two prolongations below, but 
whether these were continued into cords or not I could not 
make out. 

I believe that this is, in fact, the true nervous centre, and 
that the sac in connection with it is analogous to the ciliated 
pits on the sides of the head of the Nemertida?, to the 
" ciliated sac " of the Ascidians, which is similarly connected 
with their nervous centre, and to the ciliated sac which 
forms the olfactory organ of Amphioxiis. 

Mr. Gosse has described a similar organ in Melicerta 
riiu/ens, and 1 have had an opportunity of verifying his obser- 
vations, with the exception of one point. According to this 
observer, the cilia are continuous from the trochal disc into the 
cup ; so far as I have observed, however — and 1 paid par- 
ticular attention to the point — the cilia of the cup are wholly 
distinct from those of the disc. 

The interesting observations of the same careful observer 
upon the architectural habits of Melicerta would seem to 
throw a doubt upon the propriety of ascribing to the organ in 
question any sensorial function. 

But however remarkable it may seem that an animal should 
build its house with its nose, we must remember that a 
similar combination of functions is obvious enough in the 
elephant. 

No eyespots exist in the adult Lacinularia. In the young 
there are two red spots on the upper surface of the trochal disCj 
which are stated by Professor Ehrenberg to be seated upon 
" medullary masses" (Mark-Knotclien). I could not satisfy 
myself either of the truth of this statcMiient or the contrary, 
in consequence of the difficulty of distlnguisliing the separate 
tissues in the young animal. 

1 may be permitted here to say a word upon the nature of 
the " calcar" or "respiratory tube" of Ehrenberg, which 
exists in so many Rotifera. For his first notion, tliat it is 
connected with the reproductive systcun. Professor Elirenberg 
has substituted the idea that it is a respiratory tube, througli 
whic:h currents of water are conducted into the cavity of the 
body, and bathe the '' trembling organs " whic h he calls 



10 Huxley on Lacinularia socialis. 

"gills." Professor Ehrenberg, however, has not produced 
any evidence of such in-going currents, and Dujardin has 
denied their existence. So far as has yet been observed, 
the calcar is in immediate connection with the nervous 
ganglion. Melicerta affords a very good opportunity for ex- 
amining the structure of the organs, of which in this genus 
there are two. It is a somewhat conical process of the in- 
tegument, containing a similar process of the internal mem- 
brane. This, however, stops short a little distance from the 
extremity, and forms a transverse diaphragm, from the centre 
of which a bunch of long and excessively delicate setae pro- 
ceeds (fig. 29). I could obsene no trace of any aperture Avith 
a power of 600 diam., though of course this is merely negative 
evidence. 

Is it not possible that, as the " ciliated sac " of the Asci- 
dians has its analogue in the " fossa " of the Rotifera, so the 
calcar may answer to the " languet," which has a similar 
relation to both sac and ganglion ? 

In Notommata there is no calcar, but nervous cords proceed 
from the ganglion to the ciliated spots about the middle of 
the dorsal surface (Dalrymple). 

Repi'oductive Qi^gans. — Considering Professor Ehrenberg's 
determination of the male organs to be set aside, his descrip- 
tion of the reproductive organs extends only to the ovary, 
which, he says, in Lacinularia " lies in the posterior cavity 
of the body, and has thus one and the same outlet with the 
intestine " (p. 403). This seems to imply an oviduct ; I 
could, however, see no such organ.* The ovary consists of 
a pale, slightly granular mass of a transversely elongated form 
(fig. 5 /), and somewhat bent round the intestine ; it is 
enclosed Avithin a delicate transparent membrane, which is 
hardly visible in the unaltered state, but becomes very obvious 
by the action of acetic acid, which contracts the substance of 
the ovary and throws the membrane into sharp folds. 

Pale clear spaces, which sometimes seem to be limited by 
a distinct membrane, are scattered through the substance of 
the ovary, and in each of these a pale circular nucleus is 
contained.. The nucleus is more or less opaque, but usually 
contains 1-3 clear spots (fig. 9). 

These arc the germinal vesicles and spots of the future 
ova. Acetic acid, in contracting the pale substance, groups 
it round these vesicles, without, however, breaking it up into 
separate masses. It renders the nuclei more evident. 

* Leydig (1. c, Jt. 409) saj's that tlievc is a wide ovi<luct whicli becomes 
folded wlien empty. T must leave the discrepancy until a further exami- 
nation decides which is right. 



Huxley on Lacinularia socialis. 1 1 

The ova are developed thus : — One of the vesicles in- 
crease* in size, and reddish elementary granules appear in 
the homogeneous substance round it (fig. 10). This accumu- 
lation increases until the ovum stands out from the surface 
of the ovary ; but invested by its membrane which, as the 
ovum becomes pinched off as it were, takes the place of a 
vitellary membrane. 

In the mean while the germinal vesicle has increased in 
size, and its nucleus is no longer visible. In the ovum it 
appears as a clear space ; isolated by crushing the ovum it is 
a transparent, colourless vesicle. 

The perfect ova are oval, about 1-lOtli inch in diameter, 
and are extruded by the parent into the gelatinous connect- 
ing substance, where they undergo their development (fig. 11), 

The changes which take place after extrusion, or even to 
some extent within the parent, are — 1, the disappearance of 
the germinal vesicle (as I judge from one or two ova in 
which I could find none) ; 2, the total division of the yolk, 
as described by Kolliker in Megalotrocha, until the embryo 
is a mere mass of cells, from which the various organs of the 
foetus are developed (figs. 12, 13, 14, 15, 16). 

The youngest foetuses are about l-70th of an inch in length. 
The head is abruptly truncated, and separated by a con- 
striction from the body : a sudden nanowing separates the 
other extremity of the body from the peduncle, which is ex- 
ceedingly short and provided with a ciliated cavity, a sort of 
sucker, at its extremity. The head is nearly circular, seen 
from above, and presents a central protuberance in which 
the two eyespots are situated. The margins of this pro- 
tuberance are provided with long cilia — it will become the 
upper circlet of cilia in the adult. 

The margin of the head projects l)eyond this, and is fringed 
with a circlet of shorter cilia ; this is the rudiment of the 
lower circlet of cilia in the adult. The internal organs are 
perceived with difficulty ; but the three divisions of the ali- 
mentary canal, which is as yet straight and terminates in a 
transparent cloaca, may be readily made out. The water- 
vascular canals cannot be seen, but their presence is indicated 
by tlie movement of their contained cilia here and there 
(fig. 17). 

In youn^ Lacinularicc, l-30th of an inch in lengtli, the head 
has become triangular, the peduncle is much ("longated, and 
thus it gradually takes on the perfect form (fig. 18). The 
young had previously crept about in the gelatinous investment 
of the parents; they now begin to "swarm," uniting together 
by their caudal extremities, and are readily pressed out as 



12 Huxley on Lacinularia socialis. 

united free swimming colonies, resembling, in this state, the 
genus Conocliihts. 

The process of development of these ova is therefore exactly 
that which takes place in all fecundated ova, and would lead 
one to suspect that spermatozoa should be found somewhere 
or other. 

Now, from the observations of Mr. Dalrymple, we should 
be led to seek a distinct male form with the ordinary sperma- 
tozoa. From those of Kolliker, on the other hand, we should 
equally expect to find each individual a hermaphrodite, with 
the very peculiar spermatozoon-like bodies which he has de- 
scribed in Megalotrocha. 

I must have examined some scores of individuals of Lacinu- 
laria with reference to the former case, without ever finding 
a trace of a male individual. All were similar, all contained 
either ova or ovarium, nowhere was an ordinary spermatozoon 
to be seen. On the other hand, I found in many individuals 
singular bodies, which answered precisely to Kolliker's descrip- 
tion of the "spermatozoa" oi Megalotrocha. They hadapyri- 
form head about 1-lOOOth in. in diam. (fig. 19), by which 
they were attached to the parietes of the body, and an append- 
age four times as long, which underwent the most extraordi- 
narv contortions, resembling- however a vibrating- membrane 
much more than the tail of a spermatozoon ; as the undulating 
motion appeared to take place in only one side of the append- 
age, which was zigzagged, while the other remained smooth. 

According to Kolliker again, these bodies are found only in 
those animals which possess ova undergoing the process of yolk 
division, while I found them as frequently in those young forms 
which had not yet developed ova, but only possessed an ovary. 

Are these bodies spermatozoa ?* Against this view we have 

* Lcydig (loc. cit., p. 474) has observed, in several cases, what I de- 
scribe as jirobable spermatozoa, but considers them to be jiarasites. 

He does not notice the similarity of these bodies to those described by 
Kolliker in Meyalotrocha ; but thinks that the latter has been misled by 
the vibratile organs. 

Leydit; does not appear to bo acquainted with the imjiortant observa- 
tions of Dalrj-mple, ]Jri;.'htwick, and Goisse ; but briuL's forward as the 
true spermatozoon a teHiiua r/uid, whose description I subjoin in his own 
words: — "In alniost every colony we meet with from one to four (in larcje 
C'jlouies) individuals which are distinguishable from the rest at the first 
glance, i'y reflected li.^ht tliey apjicar (|uite white, which aj)] earance 
arises from peculiar corpuscles which fill tlio cavity of the body more or 
less comi)letely, and are driven hitler and thither by the contractions of 
the animal, as well into the wheel-organ as into the caudal a])pendago. 
Tlicy arc yellowish globular bodies, with sharp contours, l-50(X)th to 
l-1700th of an inch in diameter, with a double centre and a lighter peri- 
phery. 'J'he surface is covered l)y a mesh-work of bands projecting in- 



Huxley on Lacimdaria socialis. 13 

the unquestionable separation of the sexes in Notommata, 
and the very great difference between these and the spermato- 
zoa of Notommata. Neither are the mode of development nor 
the changes undergone by the ovum any certain test that it 
requires or has suffered fecundation, inasmuch as the process 
closely resembles the original development of the aphides {see 
Leydig, Siebold and KoUiker, Zeitschrift, 1850). 

In the view that Kolliker's bodies are true spermatozoa, it 
might be said — 1. That the sexes are united in most Disto- 
mata, for instance, and separated in species closely allied {e.g. 
D. Okenii). 

2. That the differences between these bodies and the sperma- 
tozoa of Notommata is not greater than the difference between 
those of Triton and those of Mana. 

3. That their development from nucleated cells within the 
body of Megalotrocha (teste Kolliker) is strong evidence as to 
their having some function to perform ; and it is difficult to 
imagine what that can be if it be not that of spermatozoa. How- 
ever, it seems to me impossible to come to any definite con- 
clusion upon the subject at present.* 

Kolliker supposes that Ehrenberg has seen the " spermato- 
zoa " and has taken them for the " long vibratile bodies ;" while 
Siebold imagines that Kolliker has taken the long vibrating bodies 
for spermatozoa. No one, however, who has seen both struc- 
tures can be in any danger of confounding the one with the other. 

A sexual 'propagation of Lacimdaria. — Whatever may be the 
nature of the process of reproduction jast described, there exists 
another among the Rotifera, which has been noticed by almost 
every one, but not hitherto distinguished or understood. This 
is the production of the so-called " winter ova," but which from 
their analogy with what occurs in Daplinia, I prefer to call 
" ephippial ova." 

Ehrenberg says that many ova of Hijdatina have a double 
shell, and between the two shells there is a wide space. 
" Similar ones occur in many Rotifera, in various oftcMi irre- 
gular forms: these have a much slower development, and I call 
them thence winter ova" (p. 413). Sec also his account of 
Brachiomis nrceolaris (p. 512). He does not notice the occur- 
rence of these ova in Lacimdaria or Megalotrocha. 

tcrnally, which p;ivo the body a mosaic (parqucttirtes) appearance. Im- 
moveable hairs, l-1700th of an inch long, maybe seen in isolated globules 
to radiate IVoia the surface." 

I have not observed any of these bodies. 

* 1 may mention hero that I liave found iu Mdiccrta an oval sac lying 
below the ovary, and containing a number of strongly-refracting particles 
closely resembling in size and form the heads of the spermatozoa of Laci- 
nularia. 



14 Huxley on Lacimdaria socialis. 

Kolliker speaks of the ova of Mefjolotrocha acquiring a deep 
yellow investment, as if it were a further development of those 
ova whose yolk he saw divided. I am strongly inclined to be- 
lieve, however, that he was misled by the peculiar appearance 
of the winter ova, which look as if they had undergone yolk 
division. 

Dalrymple gives a lengthened account of these peculiar ova 
in Notommata. He says that they are dark, and that their outer 
covering appears to consist of an aggregation of cells, under 
which is a second layer of cells containing pigment molecules. 
No distinct germinal vesicle, he says, is to be found in these 
ova "from the want of general transparency " (loc. cit., p. 340), 

It will be observed that all these authors consider the winter 
ova or ephippial ova and the ordinary ova to be essentially iden- 
tical, only that the former have an outer case. The truth is, 
that they are essentially different structures. The true ova are 
single cells which have undergone a special development. The 
ephippial ova are aggregations of cells (in fact, larger or smaller 
portions — sometimes the whole — of the ovary), which become 
enveloped in a shell and simulate true ova. 

In a fully grown Lacinidaria which has produced ova, the 
ovary, or a large portion of it, begins to assume a blackish tint 
(fig. 20) ; the cells with their nuclei undergo no change, but 
a deposit of strongly refracting elementary granules takes place 
in the pale connecting substance. Every transition may be 
traced from deep black portions to unaltered spots of the 
ovarium, and pressure always renders the cells with their nuclei 
visible among the granules. The investing membrane of the 
ovary becomes separated from the dark mass so as to leave a 
space, and the outer surface of the mass invests itself with a 
thick reddish membrane (fig. 21), which is tough, elastic, and 
reticulated from the presence of many minute apertures. This 
membrane is soluble in both hot nitric acid and caustic potass,* 

The nuclei and cells, or rather the clear spaces indicating them, 
arc still visible upon pressure, and may be readily seen by 
bursting the outer coat. 

By degrees the ephippial ovum becomes lighter, until at last 
its colour is reddish brown, like that of the ordinary ova; but 
its contents are now seen to Ijc divided into two masses — hemi- 
spherical from mutual contact (fig. 22), If this body be now 
crushed, it will be found that .in inner structureless membrane 
exists within the fenestrated membrane, and sends a partition 

* Lcydig (1. c, p. 453) says that the shells of the ova were not dis- 
solved by maceration in a sohition of caustic soda (cold ?) for twenty-four 
hours, and thence concludes tluxt tliey may be comjioscd of cliitin. 

The above observation tends to the contrary conclusion. 



Huxley 07i Lachmlaria socialis. 15 

inwards, at the line of demarcation of the two masses (fig. 23). 
The contents are precisely the same as before, viz., nuclei and 
elementary granules (fig. 24). This, indeed, may be seen 
through the shell without crushing the case. 

I was unable to trace the development of these ephippial 
ova any further. Those of Notommata, it appears, lasted for 
some months without change (Dalrymple). 

It is remarkable that jn Lacinularia these bodies eventually, 
like the ephippium of Daphnia, contain two ovum-like 
masses ; and there can, I think, be little doubt that the former, 
like the latter, are subservient to reproduction. 

There are then two kinds of reproductive bodies in Lacinu- 
laria : — 

1. Bodies which resemble true ova in their origin and 
subsequent development, and which possess only a single 
vitellary membrane, 

2. Bodies, half as large again as the foregoing, which re- 
semble the ephippium of Daphnia ; like it have altogether 
tliree investments ; and which do not resemble true ova either 
in their origin or subsequent development ; which therefore 
probably do not require fecundation, and are thence to be 
considered as a mode of asexual reproduction.* 

General Relations of the Rotifera. — It is one of the great 
blessings and rewards of the study of nature that a minute and 
laborious investigation of any one form tends to throw a light 
upon the structure of whole classes of beings. It supplies us 
with a fulcrum whence the whole zoological universe may be 
moved. I would illustrate this truth by showing how, in my 
belief, the structure of Lacinularia, as thus set forth, taken in 
conjunction with some other facts, gives us a clue to the solu- 
tion of the questio vexata of the zoological position of the 
Rotifera, and thence to the serial affinities of a large portion of 
the Invertebrata. 

* Lcydig distinguishes particularly between the ordinary, and what T 
have termed, the ejiliippial ova. 

His description of tlie latter agrees essentially with that which lias been 
given above ; but lie has not, 1 tliink, observed the genesis of theepliippial 
ova with sufficient care, and he tlienco interprets their structin-e by sup- 
posing that they arc ordinarily fecundated ova, which have inidergone 
a peculiar method of cleavage. The tendency of the observations de- 
tailed above, on the other hand, is to show that thev are not ova at all in 
the proper sense, but peculiar buds like those of Aphis or Gt/roddc/i/ltis, 
and as such are cajjable of develoinuent without fecundation. 

In the new edition of Pritchard's ' bifiisoria,' it is stated (]). 020'), that 
"in a recent paper by Mr. Howard on tliis species, he states tliat there 
are two kinds of reproductive bodies — one the ordinary ova, the other twice 
their size, representing gennnaj." No reference is given to Mr. Howard's 
paper, and I have been at a loss to discover it, though desirous to do justice 
to him if possible. 



16 Huxley on Lacinularia socialis. 

The curious analogy in form between the genus Stepha- 
noceros and the Polyzoa has, I believe, been the chief considera- 
tion which has led many naturalists, both in England and on 
the Continent, to arrange the Polyzoa and Rotifera together. 
This has been done in two ways, either by denying the affinity 
of the Rotifera with the Vermes, and so approximating them 
to the Polyzoa considered as organized on the molluscous type, 
or, as Leuckhart has done, by admitting the affinity of the 
Rotifera with the Vermes, but denying that of the Polyzoa 
with the Mollusca. 

I believe that there is a fundamental error in each case, 
namely, that of approximating the Polyzoa and the Rotifera 
at all. The resemblance between Stejihanoceros and a Poly- 
zoon is very superficial. No Polyzoon has the cilia on its 
tentacles arranged like those of Steplianoceros ; nor has any a 
similarly-armed gizzard : still less is there any trace of the 
water-vascular system which exists in all Rotifera. 

The relations between the Polyzoa and the Rotifera, then, 
are at the best mere analogies. 

On the other hand, the general agreement in structure be- 
tween the Rotifera and the Annuloida — under which term I 
include the Annelida, the Echinoderms, Trematoda, Tur- 
bellaria, and Nematoidea — is very striking, and such as to 
constitute an unquestionable affinity.* 

The terms of resemblance are these : — 

1. Bands of cilia, resembling and performing the functions 
of the wheel-organs, are found in Annelid, Echinoderm, and 
Trematode larvap. 

2. A water-vascular system, essentially similar to that of the 
Rotifera, is found in Monoecious Annelids, in Trematoda, in 
Turhellaria, in Echinoderms, and perhaps in the Nema- 
toidca.f 

3. A similar condition of the nervous system is found in 
Tarhellaria. 

4. A somewhat similarly armed gizzard is found in the 
Nemertidae ; and the pharyngeal armature of a Nereid larva 
may well be compared with that of Albertia. 

5. The intestine undergoes corresponding flexures in the 
Echinoderm larva*. There are, therefore, no points of their 
organization in which the Rotifera differ from the Annuloida ; 

* M. Milne Edwards, with liis accustomed acutencss, pointed out 
(Annak's des Fcienccs, 1845) the close afiinity of tlie I\otifcra with the 
Annelids, tlie Turhellaria, and the Nematoidea; but lie did not include 
tlie lOcliinoderms in the group, doubtless because, at the time lie wrote, 
sudlcierit was not known of the Ecliinodenn larva; to demonstrate their 
truly aiinuloid nature. 

t To tliesc may be added the Cestoidea and the Nemertida\ 



HuxLEv 071 Lacimdaria socialis. 1 7 

and there is one very characteristic circumstance, the presence 
of the water-vascular system, in which they agree with them. 

Now, with what Annuloida are the Rotifera most closely 
allied ? To determine this point, we must ascertain what is 
the fundamental type of organization of the Rotifera. 

Suppose in Lacimdaria a line to be drawn from the mouth 
to the anus, and that this be considered as the axis of the body ; 
suppose, again, that the side on which the ganglion lies is the 
dorsal side, the opposite being the ventral ; suppose, also, the 
mouth end to be anterior, the anal end posterior, — then it will 
be found that the lower circlet of cilia upon the trochal disc 
encircles the axis of the body, while the upper circlet of large 
cilia does not encircle the axis, but lies in the lower and an- 
terior region of the body. 

If the region behind that ciliary circlet which is traversed by 
the axis be called the post-trochal region, and that in front of 
it the pre-trochal region, we find that the circlet of large cilia 
is developed in the inferior pre-trochal region. 

Now compare this Rotifer with the larva of an Annelid. 
It will be immediately seen that the two are of essentially 
the same type, only that, while the Annelid larva is equally 
and symmetrically developed in all its regions, and has 
frequently no accessory ciliated bands, the Rotifer has its 
superior post-trochal and inferior pre-trochal regions de- 
veloped in excess ; so that the anus is thrown to the ventral, 
while the mouth is thrust towards the dorsal surface,* an 
accessory ciliated circlet being at the same time developed in 
the latter region. 

Melicerta ringens (compare figs. 26-28) resembles Lacinu- 
laria in the arrangement of its ciliated bands, only they are 
far more distorted from their normal circular form. Tubi- 
colaria closely resembles Melicerta, and there can be little 
doubt that Mer/alotrocha and Limnias are to be added to this 
division. 

In Brachionus, Philodina, Rotifer, Notommata, the same 
fundamental type obtains, but the deviation from symmetry 
takes place in a different way. 

In all these it is the ventral post-trochal region which is 
over-developed, and therefore the anus is thrown to the dorsal 
or ganglionic side. 

In Notommata the trocha appears to be simple and un- 
altered in most species, and there is no accessory circlet. 

* This over-development is not a more matter of liypotliosis. The 
yoiuig Ladnvlaria has the anus nearly terminal, and the " iiediincle"only 
subsequently attains its full proiiortions. Compare fij:. 17 and fis?. V6, 
pi. I. 

VOL. I. ^ 



IS Huxley on Lacinularia socialis. 

In N. aiirita, however, as it appears from Mr. Gosse's de- 
scription, and in Bracliioyms polyacantJius (figs. 30-33), several 
processes, three in the latter case, are developed iVom the 
superior pre-trochal region. They are richly ciliated, and 
appear to represent the accessory circlet of Lacinularia. 

Another distinct type is presented by PJiilodina (figs. 34- 
37). In this the great trocha is bent upon itself, and the 
anterior divison of it, at first sight, simulates an accessory 
circlet developed in the superior pre-trochal region. It is not 
so, however, as the continuity of the band of cilia can be 
readily traced throughout. 

To this division of the Rotifera, viz. those which have the 
anus on the same side of the body as the ganglion, appear to 
belong the genera Stephanoceros and Floscularia — at least, 
if the ganglion be what I believe it to be, a granular mass, 
in connexion with the upper part of a large oval mass com- 
posed of clear cells, and having a pit in its centre exteriorly, 
which I believe to be the altered ciliated sac. 

These might then be considered as Notommatae whose 
trochal circlet had become produced into long processes in 
Stephanoceros, while they remain as shorter knobs in Flos- 
cularia ; a tendency to which development may be traced in 
the little processes into which the trochal circlet is thrown 
around the mouths of Lacinularia and Alelicerta, and perhaps 
in the three processes which, according to Mr. Dalrymple, 
arch over the mouth in Notoimnata. 

But Steplianoceros, Pliilodina, Notommata, Bracliionus, and 
Laciimlaria are the types of the great divisions of the Rotifera, 
and whatever is true of them will probably be found to be 
true of all the Rotifera. 

We may say, therefore, that the Rotifera are organized upon 
the plan of an Annelid larva, which loses its original symmetry 
by the unequal development of various regions, and especially 
by that of tiie principal ciliated circlet or trochal band ; and it 
is curious to remark that, so far as tlie sexes of the Rotifera can 
be considered to be made out (approximatively), the dioecious 
forms belong to the latter of tl)e two modifications of the type 
which have been described, while the monoecious forms belong 
to the former. 

It is this circumstance which seems to me to throw so clear 
a light upon the position of tlie Rotifera in the animal series. 
In a Report in which I have endeavoured to harmonise the 
researches of Prof. Miiller upon the Ecliinoderms,* I have 
shown that the same proposition holds good of the latter in 

* Annals of Natural History, 1851. 



Huxley on Lacinularia socialis. 19 

their larval state, and hence 1 do not hesitate to draw the con- 
clusion (which at first sounds somewhat startling) that the 
Rotifera are the permanent forms of Ecldnoderm larva, and 
hold the same relation to the Echinoderms that the Hjdriform 
Polypi hold to the Medusa, or that Apj)endicularia holds to 
the Ascidians. 

The larva of Sipunculus might be taken for one of the 
Rotifera ; that of Ophiura is essentially similar to Stephano- 
ceros ; that of Asterias resembles Lacinularia or Melicerta. 
The pre-trochal processes of the Asterid larva Brachiolaria are 
equivalent to those of Brachionus. 

Again, the larvae of some Asterid forms and of Comatula 
are as much articulated as any Rotifera. 

It must, I think, have struck all who have studied the Echi- 
noderms, that while their higher forms, such as Echiurus and 
Sipunculus, tend clearly towards the Diopcious Annelida, the 
lower extremity of the series seemed to lead no-whither. 

Now, if the view I have propounded be correct, the Rotifera 
furnish this wanting link, and connect the Echinoderms witli 
the Nemertidae and Nematoid worms. 

At the same time it helps to justify that breaking up of the 
class Radiata of Cuvier, which I have ventured to propose 
elsewhere, by showing that the Rotifera are not " radiate " 
animals, but present a modification of the Annulose type — 
belong, in fact, to what I have called the Annuloicla, and 
form the lowest step of the Echinoderm division of that sub- 
kingdom. 

From our imperfect knowledge of the Nematoid worms it 
is difficult to form a definite scheme of the affinities of the 
Annuloida ; but perhaps they may be sketched as in the 
Diagrams, pi. III. 

These diagrams represent the arrangement of the ciliated 
bands with relation to the axis of the body in tlie Rotifera. 

Underneath eacli Rotifer is an Annelid or fuhinoderm larva, 
with its ciliary bands represented in a like diagrammatic 
manner, to show the essential correspondence between the two. 

This paper is now printed exactly as it was read before the Micro- 
scopical Society on the 31st of December, 1S51, witli the exception of 
those notes which refer to the very excellent memoir of Dr. Leydii;, imb- 
lished in February, 1852. Dr. Leydig must have been workins at the 
subject at about the same time as nij'sclf, in tlie autumn of last year ; 
and if I refer to the respective dates of our connnunications, it is merely 
for the purpose of giving the weight of iiidejiendcnt observation to those 
points (and they are the most important) in which we agree. 

It is the more necessary to draw attention to this fact, since Trofessor 
Ehrcnberg, in a late connnunication to the Berlin Academy, hints that 
the younger observers of the day arc in a state of permanent cons])iracy 
against his views. T. 11. II. 

J7>ly 9, 1852. 



( 20 ) 

On the Structure of the Rapiiides 0/ Cactus enxeagonus, Bj 
John Quekett, Esq., Professor of Histology to the Royal 
College of Surgeons of England. (Read Jan. 28, 1852.) 

Every living being that is made up of parts or organs, each 
having a definite structure, and performing a certain office, is 
termed an organized being ; and the materials, however com- 
plicated, of which it is composed, are termed organic matter. 

The components of the Alineral Kingdom, on the contrary, 
possessing little or no structure, but genei'ally being homoge- 
neous throughout, and having no adaptation of parts to per- 
form separate functions, are called inorganic or inorganized. 

If organic matter be subjected to chemical analysis, it will 
be found that in the first stage certain compounds, termed by 
some chemists proximate principles, or organic compounds or 
organizable substances by^ others, will be obtained ; each of 
which principles, by further or ultimate analysis, will yield 
simple elements. Thus, for instance, from the organized sub- 
stance termed muscle we obtain by analysis, first, fibrine, a 
proximate principle, which is its chief constituent ; and, sub- 
sequently, by the analysis of fibrine, we get the principal 
elements — oxygen, hydrogen, carbon, nitrogen, and sulphur 
in certain proportions. If, however, a mineral, or inorganic 
matter of any kind be subjected to analysis, we get no proxi- 
mate principles, but only simple elements. Organic matter 
may be found in two states, viz., in that of life or in that of 
death. Living matter possesses the powers of growth and 
integrity, may select from surrounding materials, and appro- 
priate to its uses the inorganic elements ; but in the state of 
death these powers are destroyed, and decay is the natural 
consequence. 

It is to the nature of this organic basis or matter of plants 
that I would now direct your attention, leaving that of animals 
for future consideration. 

Tn commencing our examination with the vegetable king- 
dom we shall find that inorganic or earthy matter exists in 
plants in two states, viz., 1st, as crystals, termed raphides, 
occurring in the interior of cells, and 2nd, in intimate con- 
nexion with the organic basis of the plant — in this last state 
the inorganic clement chiefly consists of silica. 

If we examine a portion of the layers of an onion or of a 
squill, or by taking a thin section of the stem or root of the 
garden rhubarb, we sliall observe many cells in which either 
bundles of needle-shaped crystals or masses of a stellate form 
occur ; these are termed raphides, from the Greek Pa(f)if, a 
needle, the first crystals discovered being of this shape. 



Quekeit:" on the Raphides of Cactus enneayonus. 21 

Raphides were first noticed by Malpighi in Opimtia, and 
were subsequently described by Jurine and Raspail. 

According to the latter observer the needle-shaped or aci- 
cular are composed of phosphate, and the stellate of oxalate 
of lime. There are others having lime as a basis, combined 
with tartaric, malic, or citric acid. These are easily de- 
stroyed by acetic acid ; they are also very soluble in many of 
the fluids employed in the conservation of objects : some of 
them are as large as the l-40th of an inch ; others are as small 
as the l-lOOOth. They occur in all parts of the plant — in the 
stem, bark, leaves, stipules, sepals, petals, fruit, root, and even 
in the pollen, with few exceptions. They are always situated 
in the interior of cells, and not, as has been stated by Raspail 
and others, in the intercellular passages.* 

Some of the containing cells become much elongated, but 
still the cell- wall can be readily traced. In some species of 
Aloe, as for instance Aloe verrucosa, with the naked eye you 
will be able to discern small silky filaments. When these 
are magnified they are found to be bundles of the acicular form 
of raphides. In portions of the cuticle of the medicinal 
sc^uill — Scilla maritima — several large cells may be observed, 
full of bundles of needle-shaped crystals. These cells, how- 
ever, do not lie in the same plane as the smaller ones belong- 
ing to the cuticle. In the cuticle of an onion every cell is 
occupied either by an octohedral or a prismatic crystal of 
oxalate of lime — in some specimens the octohedral form pre- 
dominates, but in others from the same plant, the crystals may 
be principally prismatic, and are arranged as if they were be- 
ginning to assume a stellate form. 

Tliose persons who are in the habit of examining urinary 
deposits must be familiar with the appearance of the crystjds 
of oxalate of lime, and would readily recognise their close 
resemblance to those in the cells of the onion. 

Ra])hides of oxalate of lime are found in very great abund- 
ance in the medicinal rhubarb — the best specimens from 
Turkey containing as much as 35 per cent. ; tliose from tlie 
East Indies 25 ; jmd the l^^nglish, or that sold in the streets 
by men dressed up as Turks, 10 per cent. 

Buyers of this drug generally judge of its quality by its 
grittiness, that is by the quantity of raphides it contains ; and 
this is a curious fact, as the crystalline matter cannot be of 
any beneficial importance in the action of the medicine, for the 

* As an exception I may state that, many years n\:s>, T discovored llieni 
in the interior of the spiral vessels in the stem of tiie ,!j:vap('-vine ; but 
with some botanists this woukl not be considered as an exceptional case, 
the vessels bcins regarded as elonf'ated cells. 



22 QuEKETT on tJic Rapliides of Cactus enneacjonus. 

tincture in which no raphides are contained is as efficacious 
as the powder. 

Some plants, as many of the cactus tribe, are made up 
almost entirely of raphides. In some instances every cell of the 
cuticle contains a stellate mass of crystals, in others the whole 
interior is full of them, rendering the plant so exceedingly 
brittle that the least touch will occasion a fracture, so much so 
that some specimens of Cactus senilis, said to be 1000 years 
old, which were sent a few years since to Kew from South 
America, were obliged to be packed in cotton, with all the 
care of the most delicate jewellery to preserve them during the 
transport, 

Raphides of peculiar figure are common in the bark of 
many trees. In the hiccory {Gary a alhd) may be observed 
masses of flattened prisms having both extremities pointed. 
Similar crystals are present in the bark of the lime-tree ; they 
occur in rows, their pointed extremities nearly touching each 
other, their principal situation being in the cellular tissue close 
to the medullary rays. Other forms of crystals, as the rhom- 
bohedron and a small stellate form, are also found in the bark 
of the lime. 

In vertical sections of the stem of Elceagnus angustifoUa nu- 
merous raphides of large size may be seen in the pith. 

Raphides are also found in the bark of the apple-tree, and 
in the testa of the seeds of the elm ; each cell contains two or 
more very minute crystals. 

It is at present not known what office raphides perform in 
the economy of the plant : some liave gone so far as to state 
that tljey are deposits to be applied towards the mineral part 
(^r skeletcm of tlie plant ; but the fact of their being insoluble 
in vegetable acids would prove this view of their use to be 
erroneous. Tfie more rational supposition is, that they are 
generally accidental deposits formed by the union of vege- 
table acids with lime or other base existing in the plant or 
taken up from the soil. They may, however, be formed 
artificially, and my late brother succeeded in doing so in the 
following manner: — If oxalic or phosphoric a<'id be added to 
lime-water, the precipitate will be pulverulent and opaque. 
If, however, a vessel containing oxalate of ammonia in solution 
be connected by means of a few fdaments of cotton with 
another vessel containing lime-water, crystals will be formed 
at the end of the fibres in contact with the lime-water. 

This led him to attempt to form them in the interior of 
cells : he selected for the purpose a portion of rice paper ; 
this substance was placed in lime-water under an air-pump in 
order in fill the cells with the lluid ; the paper was then dried, 



QuEKETT on the Rapliides of Cactus enneat/otuis. 23 

and the process again and again repeated, until many of the 
cells were charged with lime-water ; portions of the paper 
were then placed in weak solutions both of oxalic and phos- 
phoric acid, and at the end of three days crystals were found 
in the cells in both instances, those of the oxalic acid being of 
the stellate and those in the phosphoric acid being of the 
rhombohedral form. None of the acicular, however, were 
ever present, although the process was continued for ten days. 
One of these pieces of rice paper I now show you, and a 
stellate mass of crystals is very plainly to be seen in the centre 
of the field — each precisely resembles the rapliides found in 
rhubarb. 

The above description, which is a modification of that given 
in my lectures, well applies to the raphides in most plants, 
but the case will appear to be a little different in those plants, 
such as the cacti, which live to a great age, and in which the 
crystalline matter is in the greatest abundance. Whilst 
working at this subject about twelve months since I was in- 
duced to examine the raphides of a species of Cactus termed 
eimeagonus, a specimen of which had been given me by a 
friend as abounding in crystals. This specimen I have with me, 
just as I received it, the part containing the crystals being about 
thirty-nine years old ; that they are very numerous, and at the 
same time very large, may be known by their being visible to 
the naked eye. If any of these raphides be examined in fluid 
with a power of at least 100 diameters, they will appear to be 
made up of crystals (as far as their external surface is con- 
cerned), which project outwards in the form both of sh.irp 
pointed and truncated prisms ; and if the centre be brought 
into focus this part will be found more opaque than the rest, 
and to be of a circular figure like a nucleus. If the masses be 
mounted in Canada balsam before they are examined they 
will then present one or other of the appearances given in 
Plate III. figs. 1, 2, 3, 4 ; some, as in fig. 1, will show a nucleus 
surrounded by concentric laminae of a brown colour ; others, as 
in fig. 2, will exhibit a spot like a nucleus, first surrounded by 
concentric laminie, but towards the margin the lamina- become 
irregular, and the margin itself is comi)osed of prismatic 
flattened crystals, not clear and transparent, but more or less 
granular, whilst some other specimens, as sliown in figs. 3 and 
4, are made up almost entirely of the prismatic crystals, witli 
little or no trace of concentric laminaticm. Having found this 
to be the case I was anxious to ascertain the chemical com- 
position of these so-called raphides, and for the purpf)se I 
tried the action of various re-agents uj)on them, and noticc-d 
t'.iat the crystals were slowly dissolved in dilute liydro-chloric 



24 QuEKETT on the Raphides of Cactus enneagonus. 

acid, but I was much astonished to find that in many cases a 
basis or cast of the entire mass was left behind after the action 
of the acid had ceased ; and in most instances I could tell pre- 
cisely not only the spot where the crystals had been, but also 
form some general idea of the shape of the mass, and instead 
of their being, as I first imagined, a mass of crystals only, 
I found that there was some organic matter or basis connected 
with them. 

When one of these raphides is crushed between two plates 
of glass, the outer crystals are readily detached ; some of these 
are represented by fig. 6 : the part composing the nucleus is 
much the hardest, and exhibits a radiated and concentric 
laminated deposit, like the masses of carbonate of lime found 
in the urine of the horse. If portions of the cellular tissue of 
the cactus be examined, some cells will occasionally be found 
in which a more or less spherical mass, as shown in fig. 5, 
occurs in the centre of each : these masses correspond in every 
respect with the nuclei of the larger raphides : it would there- 
fore appear that in the early stages of development of these 
raphides the nucleus consisted of one of these spherical bodies, 
and the crystals on the exterior were formed subsequently. It 
may also happen that the bases of some of the crystals in 
process of time coalesce to form laminae, a condition not 
unlike that occurring in shell, as has been so well described by 
Dr. Carpenter, or rather like that which takes place in the 
formation of most of the laminated kinds of urinary calculi. 

My object in bringing the subject before the Society at this 
time is to ask those of our members who are chemists, and 
would be willing to look into the matter, if they could deter- 
mine the nature of the residuum or basis left after the destruc- 
tion of the earthy ingredient by means of the acid. They will 
find, as I shall presently have the opportunity of showing you, 
that there is something peculiar in the dissolution of the 
crystals — they are all, more or less, granular, as if the organic 
matter were not confined to the investing membrane, but inti- 
mately mixed up or incorporated with every atom of the lime. 
I have this day examined some sections of the Soap wood of 
China, in which stellate masses of crystals are very abundant. 
If these be acted on Ijy dilute hydrochloric acid, the earthy 
constituent will disappear, but a cast of the original mass will 
he ])roserved in what may be termed organic matter. This 
point, however, is the one which requires to be carefully ex- 
amined by persons more skilled than myself in the science of 
organic chemistry. 

As far as my observations have hitherto gone, it would 
appear to be a rule that we rarely, if ever, find inorganic 



QuEKETT on the Raphides of Cactus enneagonus. 25 

material in the vegetable or animal kingdom, except in the 
crystalline state, without the existence of an organic basis. 

Since the above was written, my friend Dr. Lionel Beale 
has been kind enough to examine the raphides in question, 
and the following is his report on the subject. 

" A few of the white globular crystalline masses were 
treated with boiling distilled water, and the aqueous solution, 
after being filtered, was evaporated to a small bulk. Upon 
examining the residue by the microscope, numerous small 
colourless crystals, in the form of obtuse rhomboids, were 
observed. The residual solution was found to give precipi- 
tates insoluble in strong nitric acid, with solutions of nitrate 
of barytes and nitrate of silver, proving the presence of 
chlorine and sulphuric acid. Oxalate of ammonia gave a pre- 
cipitate insoluble in acetic acid, but soluble in strong nitric 
acid, showing the presence of lime. 

" Hence boiling distilled water extracted a small quantity 
of soluble matter, which contained lime, chlorine, and sul- 
phuric acid, probably in the form of sulphate of lime and 
chloride of sodium. 

" Acetic Acid. — The crystalline masses were not affected by 
boiling acetic acid. 

" Potash. — No observable action was produced by boiling a 
few of the masses in solution of caustic potash. 

" Nitric Acid. — Upon the addition of strong nitric acid, 
effervescence occurred with some few of the bodies as they 
dissolved, but upon the majority this re-agent exerted little 
action in the cold. When the mixture was boiled, complete 
solution immediately took place. 

" The acid solution was evaporated to dryness ; the dry 
residue was boiled in distilled water, and the filtered solution, 
after concentration, was allowed to remain in a still j)lace lor 
some time. Upon examining the residue with the micr()sct)pe 
numerous well-formed octohedra of oxalate of lime were ob- 
served. 

" Another portion of the original matter was incinerated : — 
the masses still retained their globular form, but became black, 
and the products of combustion burnt with a blue lam1)ont 
flame. After exposure to a dull red heat for three or four 
hours, the crystals were perfectly decarbonized, and by the 
unaided eye could scarcely be distinguished from those which 
had not been incinerated. Upon microscopical examination, 
however, the crystalline fragments of which the crystalline 
masses were composed, were found to have acquired a dark 
granular uneven surface, and the sharpness of outline had been 



26 QuEKETT on the Rajjhides of Cactus enneacjonus. 

destroyed. The decarbonized residue was entirely dissolved 
in acetic acid with brisk effervescence ; and upon the addition 
of a solution of oxalate of ammonia to the acid solution^ an 
abundant white precipitate was immediately produced ; this 
was soluble in stiong nitric acid, but insoluble in excess of 
acetic acid — oxalate of lime. In all probability, therefore, the 
crystalline masses consisted of — 

"I, A little organic matter ; 

" 2. Sulphate of lime ; 

" 3. A little of carbonate of lime ; 

" 4. Traces of chloride of sodium ; 

" 5. A vegetable salt of lime, containing a considerable pro- 
portion, or consisting entirely of oocalate of timer 



On the occurrence of a Membranous Cell or Cyst upon the 
Olfactory Nerve of a Horse, containiny a larye Crystal of 
Oxalate of Lime. By James B. Simonds, Esq. (Read 
April 28, 1852.) 

The recent publication of Mr. Quekett's lectures on the occur- 
rence of earthy salts in both animal and vegetable cells gives 
an unusual interest to these depositions, and more especially 
when they are met with in those parts of the organism of 
animals where we should scarcely anticipate their presence. 
For this reason, and as an addendum to his valuable papers 
now being read before the Society, I am induced to bring 
before you an interesting and novel fact which has lately 
come to my knowledge relating to a deposit of the oxalate of 
lime within a cell or small membranous cyst. 

In the latter part of March a pupil of the Royal Veterinary 
College found, in dissecting the brain of a horse which had 
been procured from the slaughterhouse, a small transparent 
cyst, possessing a very bright or glistening aspect, attached to 
the bulbous portion of the right olfactory nerve. The speci- 
men, together with a small portion of tlie nerve, was carefully 
removed, and a day or two afterwards it was kindly presented 
to me, he at that time believing it to be an hydatid. 

From having been kept in water I found that the nerve was 
somewhat decomposed, and very readily se])arated into a pulpy 
mass ; a circumstance which prevented any minute examina- 
tion of its structure being made. I observed, liowever, that its 
sul)stance was partly absorbed, so as to form a cup-like con- 
cavity for the lodgment of the cyst ; and I am led to infer 
from this circumstance that the sense of smell of the animal 



On a Cyst upon the Olfactory Nerve of a Horse. 27 

was greatly interfered with, and probably rendered very 
obtuse. But of this, as well as the existence or otherwise of 
pain from the pressure of the cyst, we are without means of 
ascertainins. 

On placing the specimen under the microscope, and viewing 
it with a two-inch object-glass, I was surprised to find a large 
octohedral crystal of oxalate of lime, with beautifully de- 
fined facets freely floating in a limpid fluid which distended 
the walls of the cell. There appeared to be no obstacle to the 
passage of the crystal from side to side of the cavity or in any 
other direction when the specimen was placed in different posi- 
tions, its weight quickly carrying it to the most depending part. 
The walls of the cell have every indication of being composed 
of layers of areolar tissue spread out in a membranous form ; 
they are not, however, of uniform thickness throughout, 
although everywhere very translucent. Towards the circum- 
ference or periphery of the cell on one side there exists 
a bell-shaped spot {a Fig. 1, PI. IV.), which is thinly co- 
vered with membrane, but surrounded with many fibres, far 
more dense than in any other part. Besides the crystal within 
the interior there is a small mass of granular-like matter, 
which can also be made to vary its position; this mass is 
marked h. 

The occurrence of this deposition of the oxalate of lime in 
this situation is the more interesting from the circumstance 
that this salt of lime is very rarely met with in the urine of the 
horse, in which the carbonates, on the contrary, are very com- 
mon. Various forms of the carbonate of lime are noticed in 
the urine of the herbivora, produced by causes disturbing its 
ordinary mode of crystallization ; but none of these forms can 
be confounded with tlie octohedral arrangement of the oxalate. 

The priority of the formation of the cell or the crystal is not 
easy to be determined, it being possible that the blood of the 
animal, from impregnation with the oxalate of lime, deposited 
this salt in the place it was found, and that subsc^quently a 
cell enclosed it to prevent any serious ill consccjucnces to the 
surrounding organism ; or it may be that tlie <ell was first 
formed, and then the salt was efTused into its interior, where 
it led to the exudation also of fluid. It is perliaps right to 
mention, in conclusion, tliat several cajiillary vessels are to be 
observed ramifying upon the walls of tlie cyst, and that it was 
firmly held in its place by fibres of areolar tissue. 1 may also 
add that the crystal has not been measured to ascertain its 
exact size, but that it can very readily be seen by unassisted 
vision. 



( 28 ) 

On the Development of Tuhularia indivisa. By J. B. Mum- 
mery, Esq. [Read May 26, 1852.] 

Having found considerable difficulty in reconciling the accounts 
given by various naturalists of the development of Tuhularia 
indivisa, I was gratified to have discovered a locality whence I 
could obtain by the dredge a regular supply of fresh speci- 
mens of that very interesting zoophyte ; and during the past 
six months have made almost daily observations by the micro- 
scope upon its structure and development. 

The painstaking investigations of the late Sir John Graham 
Dalyell appear to have supplied much of the information pub- 
lished on the subject. 

It appeared however to me, on comparing the results of my 
own observations with the accounts and figures contained in 
the work of that indefatigable observer, that he had ever 
laboured under the disadvantage of employing a very imperfect 
microscope, and consequently misapprehended some of the 
phenomena to which he directed his patient attention. 

The general form of Tuhularia indivisa has repeatedly been 
well described, but there are some portions of its structure re- 
specting which gi-eater accuracy appears desirable. The repro- 
ductive gemmules have usually been described as originating at 
the base of the lower row of tentacules, and, owing to the pro- 
fusely crowded situation of these oviform bodies in the full- 
grown head, it is quite impossible to detect their real place of 
attachment to the body. It is however a well-known fact, 
that the full-grown head within three or four days drops from 
the stalk, and that in the course of six or seven days a new head 
is produced from the medullary pulp. On examining the 
newly-formed head, under a magnifying power of fifty diame- 
ters, the oviform gemmules are even at this early stage per- 
ceptible, arranged upon the outer surface of the body, and ex- 
tending vertically from the lower tentacules to the base of the 
oval tentacules in twelve equidistant lines ; two of the lower 
tentacules orighiating in the space Ijetween each ovary, thus 
making the whole number twenty-four. 

In the early stages of their growth the capsules arc attached 
to the ovary by a very short and somewhat thick stalk ; the 
stalk gradually becomes elongated, having the cajjsules affixed 
alternately on each side throughout its length by a broad attach- 
ment, and the substance of the capsule is now of a pale rose- 
colour. 

As development advances the general rosy tint disappears, 
and the colouring matter appears concentrated in a well-defined 
organ of deep-red colour, which evidently supplies the connect- 



Mummery on the Development of Tuhularia indivisa. 29 

ing link between the stalk and the enclosed embryo, and has 
been denominated the placental column. The pedicle, attach- 
ing the capsules to the stalk, having now become much smaller 
in proportion, the stalk, with its capsules, presents the appear- 
ance of a bunch of grapes. Sir John Dalyell declares his in- 
ability to discover the ascending and descending currents con- 
veying granular matter, which have been observed in the stem 
of Tubularia by several naturalists. In addition to these, how- 
ever, I have distinctly noticed similar, though not equally ener- 
getic currents, in the stem supporting the reproductive gem- 
mules. 

The writer just named appears to have never detected more 
than one embryo in each cyst, but in some specimens I have 
found each cyst in the gioup to contain two, and occasionally 
even three embryos, distinctly perceptible through the sides of 
the cyst, which is sometimes quite transparent. 

While some clusters are fast approaching maturity, others, 
attached to the same ovary, are still in the very earliest stages 
of growth. 

As the contents of the capsules at length arrive at maturity, 
a bright red spot (which for some weeks past had become per- 
ceptible at the apex of the capsule) is observed slowly to 
expand in a quadrangular form, presenting the appearance 
shown in fig. 3, PI. IV. 

The basal extremity of the nascent animal is now seen 
slowly emerging, — the drawing (in the particular instance 
illustrated) exhibiting the progress of development at intervals 
of an hour, commencing at 8 30 p.m., and concluding at 
1 30 A.M., when the process of extrication was complete. 
The extremity which will form the future point of attachment 
in the fixed state of the young animal is always presented 
towards the aperture of the capsule, which appears to be 
dilated solely by the efforts of the animal. 

Slowly it emerges, withdrawing its tentacles in succession, 
until it has set itself free, when it crawls slowly up(m the 
bottom of the vessel containing it, elevating itself on the 
extremities of its eight tentacles. 

After a period of time, varying from one to four days, the 
animal (which, in its free condition, has never l)cen remark- 
able for activity), having selected a suitable stone, or the 
surface of an old polypidon, reverses its position, and, with 
the mouth upwards, now attaches itself by the opposite ex- 
tremity, and remains rooted fast for life. 

In every instance that has come under my notice, the first 
animal that escapes is of an ellipsoidal form, not very greatly 



30 Ml'mmery on the Development of Tubularia incUvisa. 

differing from the adult, excepting in the number of its ten- 
tacles. Within five minutes after the extrication of the animal 
already described, a second escapes through the dilated mouth 
of the capsule, but differing greatly from the former in con- 
figuration. It closely resembles, in miniature, a young spe- 
cimen of one of the star-fishes {Solaster papposa), presenting 
a discoidal form, surrounded by twelve obtuse tentacles. 

In the course of thirty-six hours this had greatly changed 
in form, and, within a few days after, the two varieties pre- 
sented but slightly different aspects, especially after they had 
fixed themselves. The empty capsule, or ovisac, with its 
contained placental column, remains dilated, exactly as when 
the young animals quitted it. 

After the lapse of about six weeks, the animals, which were 
previously colourless, gradually acquire a pale rose tint around 
the head, and eventually the ovaries are developed as it ap- 
proaches the adult state. 

Much difficulty is experienced in preserving this zoophyte 
in a healthy state for examination, but it may be worth ob- 
serving that I at length succeeded tolerably well by connect- 
ing a syphon of gutta percha with a reservoir of salt water, 
and thus causing a small stream to fall from a height of several 
feet upon the surface of the water containing the specimens, 
and allowing the surplus water to overflow into a larger re- 
ceptacle. The agitation thus produced had the effect of 
retarding the fall of the heads. 

I trust I may be pardoned for referring to the highly in- 
teresting suggestion of Professor Forbes, in his admirable 
treatise on the naked-eyed Medusae, viz. : That possibly all 
the Medusae are, at one period of their life, fixed animals, as 
proved by Sars in the case of Cyanea aurita ; and that, con- 
versely, many of the zoophytes may be found to pass through 
a medium stage of existence, during which the germs are 
developed from which the zoophyte is reproduced, — as in the 
instances of Laomedea and Cyanea. 

As the latter zoophyte presents so close an affinity to the 
subject of my remarks, I have most carefully repeated my 
observations, and feel convinced that the animal which 
escapes from the pedunculated capsule is distinctly trace- 
able througli all its stages, until, when fixed, it becomes 
the adult Tithularia, and that it undergoes no intermediate 
metamorj)Iiosis, or .dtornation in its mode of existence ; I 
have thouglit it j)ossible that the eight-armed creature might 
prove a Medusoid. 



( 31 ) 

Some Observations on the Structure and Development of Vola ox 
GLOBATOR, aud its relations to other unicellular Plants. By 
Geo. Busk, Esq., F.R.S. (Read May 26, 1852.) 

Three forms, or, as they are commonly regarded, species of 
Vblvox are described and figured in Ehrenberg's great work, 
and have been noticed by other observers. These are V.glo- 
bator, V. aureus, and V. stellatus. A fourth very similar or- 
ganism has also been described under the name of Sphairosira 
Volvo X. 

As I regard the three first named of these at all events, 
merely as forms or phases of one and the same species, the 
following observations will apply in some respects to all of 
them. They have more particular reference, however, to the 
common form of V. gtohator, which happens to be that most 
accessible to me. 

This beautiful and well knoAvn object, which was first 
noticed by Leeuwenhoek, received little satisfactory elucida- 
tion until it fell under the observation of Ehrenberg, whose 
account of its structure and notions respecting its nature have 
been adopted by most subsequent observers, and have been 
received with little opposition until very lately — in fact until 
the beginning of last year. At that time Professor William- 
son read a paper on the subject before the Manchester Lite- 
rary and Philosophical Society, which is published in the i)th 
volume of their Memoirs. 

Professor Williamson's observations have led him to con- 
clusions in many points opposed to those arrived at by 
Ehrenberg, and especially are they confirmatory of Sicbold's 
original view of the vegetable nature of Volvox. With respect to 
some points of structure, however, concerning which Professor 
Williamson differs from the Prussian ol)server, 1 am inclined, 
from my own observations, to side with the latter, whose 
errors in the case of Volvox are not those of direct observa- 
tion ; but in this instance, as in very many others, it is ol)vious 
that Ehrenbbrg has allowed his imagination, working upon 
preconceived notions, to play the j)art of reason in the inter- 
pretation of correctly-observed phenomena ; he has thence, 
in the explanation of what lie has seen correctly, fallen occa- 
sionally into gi'eat and important errors. Whilst it cannot 
be denied that the recent progress of knowledge with resj)ect 
to the structure and nature of the lowest classes of organiscnl 
beings, places an observer of the present day in a j)ositi()n so 
much more advantageous, that it is s( arcely fair to institute a 
<'omparison between him and the great and lal)orious Prussian 
microscopist, at the time his principal works were written. 
VOL. I. d 



32 Busk on Volvox globator. 

still it is much to be regretted that these modern lights, clear 
as they are, have not apparently been allowed to penetrate 
his mind, and that one to whom science is so much and so 
deeply indebted should retain views long since deservedly 
exploded by nearly all competent observers. 

The more common and best known form of Volvox glohator, 
to the naked eye, or under a low power, appears as a trans- 
parent sphere, the surface of which is studded with numerous, 
regularly placed green granules or particles, and which con- 
tains in the interior several green globules, of various sizes in 
different individuals, though nearly always of uniform size in 
one and the same parent globe. 

These internal globes, which are the young or embryo 
Volvox, at first adhere to the wall of the parent cell, although 
the precise mode of connexion is not very apparent. When 
thus affixed, they are in a different concentric plane to the 
smaller green granules. At a later period, and after they have 
attained a certain degree of development, these internal globes 
become detached, and frequently exhibit a rotatory motion, 
similar to that of the parent globe. 

In the form of Volvox, termed V. aureus by Ehrenberg, 
the outer sphere, or cell, exhibits precisely the same structure 
as the above, the only apparent difference between them con- 
sisting in the deeper green colour of the internal globules. 
These, however, soon exhibit a more important distinctive 
character in the formation of a distinct cell-wall of consider- 
able thickness around the dark green globular mass. This 
wall becomes more and more distinct ; and, after a time, the 
contents, from dark green, change into a deep orange-yellow ; 
and simultaneously with this change of colour the wall of the 
globule acquires increased thickness, and appears double. 

The third form, or Volvox stellatus, differs in no respect 
from the two former, except in the form of the internal 
globules, which exhibit a stellate aspect, caused by the pro- 
jection on their surface of numerous conical eminences, formed 
of the hjaline substance, of which the outer wall of the 
globule is constituted. The deep green colour of the contents 
of these stellate embr^yos, and their subsequent changes into an 
orange colour, at once point out their close analogy with those 
of V. aureus. I have no doubt of their being merely modi- 
fications of the latter ; and, in fact, the two forms are very 
frequently to be met with intermixed, and on several occasions 
I have observed smootli and stellate globules in the interior of 
one and the same parent globe. 

The organism described and figured hy Khrenberg, under 
the name of Spluerosira volvox, also presents the appearance 



Busk on Volvox glohator. 33 

of a transparent globe set with green spots, but it differs from 
the foregoing in two important respects. 

1. In the absence of any internal globules or embryos. 

2. In the irregular size of the green granules lining the 
wall, which, instead of being of a uniform size, are of various 
dimensions (fig. 13, PI. V.). The different sized granules are 
irregularly disposed, although, in relation to the sphere itself, 
they, or rather the centres of them, are as regularly dis- 
tributed as in the three just-described forms. What is rather 
remarkable with respect to this form is the circuinstance, that 
the larger granules are not disposed over the whole periphery 
of the sphere, rarely occupying more than two-thirds oi it, 
towards one side. In the more minute description of the 
elements of the above-mentioned organisms, the investigation 
of which requires the higher powers of the microscope, it 
will be convenient to commence with the common Volvox 
glohator; and as the tracing of the development of the internal 
embryonic globules affords the readiest road to a compre- 
hension of the true structure of the mature globe, I shall pro- 
ceed in that course. 

The internal embryonic globules are visible in the young 
Volvox while still within the parent ; but as they are at first 
concealed by the density of the wall of the young Volvox, the 
very earliest stage of formation of the embryo cannot be 
readily noticed. In the earliest state in which these bodies 
can be observed, they appear as a globular, or rather discoid, 
nucleated cell (fig. 3), which, besides its apparent central 
nucleus, contains a number of minute spherules placed towards 
the periphery. At this time no distinct wall can be detected, 
the whole embryo (to use a convenient though incorrect term) 
apparently consisting of a homogeneous substance, with a 
lighter nuclear-looking space in the centre, and the above- 
mentioned spherules towards the periphery. This nucleated 
cell, as it may be termed, although witliout a cell-wall, in- 
creases in size, and the solid or coloured contents aj)pear to 
retreat from the centre, which becomes clearer and clearer 
towards the periphery, which gradually becomes more and more 
opaque. As the cell grows, the nucleus (?) seems to disap- 
pear, or to be converted into the clear central space ; or, it 
may be, broken up and confounded in the more oi)aque con- 
tents. The number of spherules increases as the cell grows, 
and it is very soon apparent that the now very thick jinrietal 
deposit of cell contents is breaking up into small portions or 
lobular masses, tlie centre becoming clear, and apparently 
filled only with a clear aqueous fluid. When the cell has 
thus acquired a considerable size, the contents begin to un- 

(12 



34 Busk on Volvox globator. 

dergo segmentation, as pointed out in the case of Volvox — 1 
believe first by Professor Williamson. This process com- 
mences and proceeds precisely as in the ova of animals — the 
contents dividing first into two, and then each of the halves 
into two, and so on, till the division becomes too minute to 
allow of the counting of the segments. It is to be remarked, 
moreover — and I think this has not been noticed before — that 
the bright spherical bodies multiply quite as rapidly, if not in 
a more rapid ratio, up to a certain point, than the segmenta- 
tion goes on, so that each segment of the still-dividing mass 
always exhibits two, three, four, or even more of these par- 
ticles (figs. 1, 2). Ultimately the segmentation ends in the 
formation of innumerable green bodies, which are closely 
packed round the periphery of the cell. These bodies, though 
perfectly defined, are not at first separated by any clear space, 
and each contains at least one of the bright spherules alluded 
to (fig. 3). By their mutual pressure, these soft corpuscles of 
course assume an hexagonal figure, and they are now about 
l-4000th of an inch in diameter, or rather more. As soon as, 
or even before, the segmentation commences, a distinct though 
delicate membrane, surrounding the embryonic mass, is quite 
evident, as described by Mr. Williamson ; and beyond this is 
usually to be observed a very delicate zone of apparently 
gelatinous matter, which is sometimes so delicate as to escape 
observation, but may, I believe, always be detected by the 
use of a solution of iodine. 

When the segmentation is completed, in the way above de- 
scribed, the embryo Volvox exhibits the appearance of a sphe- 
rical body composed of a transparent membrane lined with 
distinct, uniform-sized, contiguous hexagonal masses. It con- 
tinues to grow, and very soon clear lines become apparent 
between tlie green masses, which are thus very distinctly 
defined, retaining the same hexagonal form — each with an 
apparent nucleus, which is probably derived from the bright 
spherule contained in it, but as yet without brown spot, clear 
space (vacuole), or vibratile cilia. As the embryo continues to 
grow, the spaces between the green masses continue to in- 
crease ; the green bodies gradually lose the hexagonal form, 
and assume the appearance of the ciliated zoospore next 
to be described. Tliey are now about l-3000th of an inch, or 
thereabouts, in diameter, and the embryo, detached from its 
parent, becomes a free Volvox in its interior. We have thus 
arrived at the complete Volvox, and from the mode of its for- 
mation it is apparent that it consists of a transparent wall 
lined with the green bodies, and hollow in the interior; and 
also that it is surrounded, at all events while within the 



Busk on Volvox rjlohator. 35 

parent, with a delicate transparent areola, apparently of gela- 
tinous matter We have now to examine more minutely the 
structure and nature of the green granules, and the further 
changes they undergo. 

Upon examination of the wall of a full-grown V. qlohator 
with a sufficient magnifying power, it will be seen, upon view- 
ing the edges, as it were, of the image in the field, with the 
object so arranged as to bring the equatorial plane exactly into 
focus (fig. 5), that the green granules are, in fact, vesicular or 
semivesicular bodies of a flask-like or conical form, about 
l-3000th of an inch in transverse diameter, and placed at 
uniform distances apart. Each of them is prolonged out- 
wardly into a sort of peak or proboscis of a transparent and 
colourless or hyaline material, and from which proceed two 
very long vibratile cilia, which in close contact at first, pass 
through the parent cell-wall, upon the outer side of which 
they separate widely and perform very active movements. The 
outer cell- wall presents a minute infundibuliform depression at 
the point of exit of the cilia. It will also be observed, that 
each ciliated cell or zoospore, as it may analogically be termed, 
contains a green granular mass or masses, composed, for the 
most part probably, of chlorophyll granules and a more trans- 
parent body, which I suppose may be regarded as a nucleus, 
and derived, as it would appear, from one of the bright sphe- 
rules which have been noticed before. At an early period after 
the maturity or completion of the zoospores they exhibit a 
minute, circular, clear space, or sometimes, but I think rarely, 
more than one, which is worthy of very attentive considera- 
tion. This space is of pretty uniform size in all cases, and 
about l-9000th of an inch in diameter. It may be situated in 
any part of the zoospore, or not unfrequently in tlie base, or 
even in the midst of one or other of the bands of protoplasm 
connecting it with its neighbours. Its most important charac- 
ter consists in its contractility — a property already known to 
be possessed by similar spaces or vacuoles in vegetable spores. 
But what appears to me a very curious, and as yet unnoticed 
peculiarity of this contraction, consists in the fact that it is 
very regularly rhythmical. In several cases in which I have 
watched the phenomenon In question, uninterruptedly, for sonic 
time, the contractions or pulsations occurred very regularly at 
intervals of about 38" to 41". In one case, however, if I was 
not misled in the observation, the interval was about twice 
this, viz., I' 25". Tlie contraction, which appears to amounl 
to complete obliteration of the cavity of the "vacuole,'' takes 
place rapidly or suddenly, as it were, whilst the dilatiition is 
slow and srradual, The interval above noted was measured 



36 Busk on Volvox ghhatur. 

between one sudden contraction and tlie next, and about hall 
of it perhaps was taken up by the slow dilatation of the space. 
This contractile vacuole always reappears in precisely the same 
spot. It would seem to exist, or at all events to present a 
contractile property only for a limited period, and to disappear 
soon after the formation of the brown spot, when, as I con- 
ceive, the zoospore has reached its maturity. The most 
favourable cases in which this contractile space is to be sought 
for, are those in which the Volvox is in the most vigorous state, 
and especially in that variety in which, owing perhaps to the 
copious supply of nutritive matter, the amount of protoplasm 
is very abundant, and the zoospores consequently very numer- 
ous and connected to each other, not by slender filaments but 
by wide processes, as in figs. 2^, 27, which latter shows a 
contractile space situated in the base of one of the connecting 
bands of protoplasm. With the exception of the small space 
occupied by this contractile spot, the zoospore at first appears 
to be quite solid, and no distinct wall can be perceived around 
the green matter, but it rapidly changes. Owing either to the 
expansion of the vacuole, above described, after it has lost its 
contractile property, or to the formation of others of a different 
nature, and also perhaps in some degree to the absorption or 
consumption of some of the colouring contents, the zoospore 
gradually becomes more and more transparent (fig. 7) ; till at 
last, the greater part of it is clear and colourless, and what 
remains of the green matter contracts into a small irregular 
mass, adherent to the bottom or sides of what is now" a cell — 
primordial cell of Cohn. (Figs. 5, 6.) 

Each cell, when fully formed, usually presents a broAvn 
spot, which is adherent to one side of the cell towards the 
narrow end (figs. 5, 6) ; and what is remarkable, it will be 
noticed in a perfect specimen, that the brown spots are placed 
in a corresponding situation in all the cells, that is to say, all 
the cells appear to look the same wav. This is the so-termed 
eye-spot of Ehrenberg. When examined with a high power 
(800 — 900 diam.) it presents the form of a cup or disc, con- 
cave on the side which looks outward, and convex on the 
other. Though placed quite on the side of the cell, and pro- 
jecting a little upon it, the brown spot is nevertheless always 
covered by a thin membranous expansion of protoplasm, or, in 
other words, it is always lodged witliin the substance of the 
zoospore. Thougli most usually present, the brown spot does 
not appear, in all cases, to be at any period a necessary con- 
stituent of the zoospore. It is one of the most persistent 
liowever, remaining visible as long as any portion of the zoo- 
spore is discernible. Besides the above-described elements, the 



Busk on Volvox glohator 37 

zoospore, when viewed from above, exhibits two higlily refrac- 
tive spots placed side by side, which seem to represent the 
insertions or origins of the two vibratile cilia. 

The periphery of the cell presents a clear line, and appears 
to be formed of a delicate membrane — although, in the earlier 
stages of the existence of the zoospore, that is, before the for- 
mation of the eye-spot, or disappearance of the contractile 
vacuole, the whole evidently consists of a homogeneous sub- 
stance, in which the above described parts are imbedded. 
From the periphery of the zoospore proceed six thread-like 
processes, connecting it with as many of its neighbours. These 
threads appear to be simply continuations of tlie quasi cell- 
wall, and to be of the same nature chemically as it, as are also 
the vibratile cilia. The connecting threads are sometimes 
double, or even triple, between some one or more of the sur- 
rounding cells, and they are invariably continuous between the 
two cells. 

This description applies more particularly to the zoospores 
in situ. When the Volvox is ruptured, many appear to be- 
come immediately detached, and to be washed out, as it were, 
with the aqueous contents of the parent cell. Under these 
circumstances they lose some of their previous regularity of 
form, but not much ; they become more globular and the 
beak less prominent, but in other respects they appear much 
the same as before. The two vibratile cilia remain in con- 
nexion with them, and continue their active movements. This 
is opposed to Mr. Williamson's statement, that " when thus 
liberated they exhibit no traces of the two cilia, or probos- 
cides" of Ehrenberg, and agrees with that of the latter. 
Among the thus liberated ciliated zoospores will usually be 
found numerous detached cilia, which, as is observed by Mr. 
Williamson, are generally more or less coiled at one end into a 
ring. And besides these I have not unfrequently noticed some 
extremely delicate annular bodies, about 1 -9000th of an inch 
in diameter, perfectly clear and colourless, whicli seem as if 
they had escaped from the interior of the ruptured zoospore : 
but of this and their true nature 1 am unable to speak posi- 
tively. 

Having thus described what I conceive to be the anatomy of 
the common form of Volvox glohator, 1 will thus sum up the 
result of what my observations have led me to conclude as to 
its structure. 

1 . That it originates in an apparently nucleated, discoid 
cell, which is generated in tlie interior of the parent, and 
liberated in a perfect, though not fully matured form ; within 
which are contained similar germs. 



38 HvsK on Volvox globator. 

2. That the contents of this apparently nucleated discoid 
cell, consisting of a grumous material and refractive amyla- 
ceous (?) spherules, after a time undergo segmentation, at 
the same time exhibiting a distinct wall, beyond which is a 
delicate areola, apparently of a gelatinous consistence. 

3. That this segmentation, attended with a corresponding 
augmentation in the number of the refractive spherules, ter- 
minates ultimately in the formation of numerous contiguous 
particles or segments. 

4. That these ultimate segments are gradually separated 
from each other, remaining connected only by elongated pro- 
cesses or filaments, and constitutin^i, the ciliated zoospores of 
the m.ature Volvox. 

5. That these zoospores at first are simple masses of pro- 
toplasm, containing a transparent nuclear body, and that 
afterwards they present for a time clear, circular spaces, which 
contract rhythmically at regular intervals ; and are subsequently 
furnished with a brown eye-spot ; and at a very early period 
with two long retractile cilia, which, arising from an elongated 
hyaline beak, penetrate the parent cell-wall, and exert active 
movements external to it. 

6. That in a concentric plane internal to these ciliated zoo- 
spores are placed the germs of future individuals destined to 
follow the same course. 

Having thus traced one form of Volvox through its course of 
development, I will proceed much more briefly to the others. 

In V. aureus, as I have said, the constitution of the wall of 
the parent cell is exactly as above described. At its earliest 
appearance also the internal embryonic body caimot be dis- 
tinguished from that of the ordinary form, except in its deeper 
green colour. It afterwards, however, acquires a thick wall, 
changes its colour to yellow without material alteration in size, 
and acquires a second equally firm and distinct envelope, or 
rather, as I believe, the original contents contract somewhat, 
and then form a second coat around themselves. Eventually 
a considerable space exists between these two coats (figs. 
10, 12), which space is occupied by a clear and apparently 
aqueous fluid, but upon the addition of a solution of iodine a 
granular cloudiness is produced in this fluid. The contents of 
the inner cell consist chiefly of amylaceous grains mixed with 
a greenish material in the one case, and with a bright yellow 
apparently oily fluid in the other. Tlie amylaceous particles 
are of an irregular botryoidal form, and far fi"om uniform in 
size. As regards the future destination of this form of germ, 
I am as yet in total ignorance ; there can, however, I think, be 
little doubt but that it represents the " still " form of spore of 



Busk on Volvox globator. 39 

other Alo^.-r — that it may, in fact, be termed the " winter 
spore'' of Volvox, destined, owing to its more persistent vi- 
tality, to continue the species, when its course of development 
in the usual way is interrupted by surrounding circumstances. 

Of that form of Volvox termed V. stellatus, I would only 
here observe that it seems to me merely a modification of the 
one last described, and that it appears to follow the same 
course of cliange and doubtless of future development. 

With respect to Sphoirosira volvox, my observations have 
been very limited, and I by no means desire to express myself 
with certainty as to its relationship to the forms above de- 
scribed. I merely surmise that it may be found to represent 
a peculiar mode of development of one and the same species. 

In external aspect, except in the want of uniformity in the 
size of the ciliated zoospores, it appears to agree in all respects 
with V. globator. It however contains no internal embryonic 
bodies, and it is therefore only to the ciliated cells that any 
reference need here be made. The smaller ones appear to 
me to resemble in all respects those of Volvox globator, and 
each to possess two cilia, which is important if true, because 
the only distinction between Volvox and Spharosira in Ehren- 
berg's classification depends upon the circumstance, that in 
SphcBrosira there is only a single cilium to each zoospore, whilst 
there are two in Volvox. 

My supposition that SphcBrosira volvox and V. globator are 
allied, is founded, it must be owned, not upon any direct ob- 
servation, but chiefly upon the fact, that in the water in which 
the specimens of Volvox I had under examination were con- 
tained, there was at first none of the Sphccrosira any more 
than of V. aureus observable, and that after some days both 
were very numerous. 

The difference I am about to destribe in the after develop- 
ment of the ciliated zoospores, is not by any means a sufficient 
ground upon which they should be deemed distinct species, 
because much greater differences are known to exist in other 
of the lower Algae during their various forms of development 
without its being thence allowable to suppose tliat they are of 
different species. 

In Volvox spharosira then, as at all events it may be termed, 
the larger green granules are in fact the ciliated zoospores in a 
stage of further progressive development. In the same spe- 
cimen they will be seen in all stages of division or segmenta- 
tion (fig. 13) — first into two, then into four, and so on till, as 
in tlie case of tlie embryo Volvox, the ultimate result of the 
segmentation constitutes numerous minute ciliated cells or 
bodies (fig. 14)— not, however, as in that case, lining the 



40 Busk on Volvox glohator. 

inner surface of the wall of a spherical case, but formino: by 
their aggregation, a discoid body, in which the separate fusi- 
form cells are connected together at one end, and at the 
other are free, and furnished each with a single cilium. In 
this stage these compound masses become free and swim 
about in the water, constituting, in fact, a species of the genus 
Uvella, or of Syncrijpta of Ehrenberg. 

With respect to the chemical constitution of the above 
described parts, t1^.e following are the results at which I have 
arrived : — 1 . By the use of iodine and sulphuric acid, tried 
repeatedly and in various ways, I have never succeeded satis- 
factorily in eliciting any tinge of blue in the wall of the mature 
Volvox. I therefore conclude that it contains no cellulose. It 
is invariably coloured, by the above re-agents, of a deep brown 
colour, and when thus coloured, this outer wall presents no 
trace whatever of structure ; it appears uniformly transparent 
and homogeneous. The ciliated zoospores, also, with the 
connecting filaments and cilia, are turned brown, but of a very 
deep brown, by the same re-agents, excepting usually one or 
more particles in the interior of each, which are apparently 
turned blue. I am not satisfied as to the chemical re-action of 
the brown spot ; it appears to assume a blue colour, but from 
the intensity of its colour and consequent opacity I am not 
sure that this is the case. 

The embryo cell, when young, is turned a deep brown, 
but when older and fully formed, but before it has aiTived at 
maturity, it will be found that it is only the green masses, or 
future ciliated zoospores, that are thus changed, the cell-wall 
acquiring scarcely any tinge of brown. But when a young 
cell thus tested with iodine and sulphuric acid is ruptured, I 
have occasionally noticed that the fluid contents contain an 
abundance of minute bluish flocculi — I use the word flocculi 
because the particles are light and flocculent, and not at all like 
any of the more ordinary and more solid forms of amylaceous 
matter. The quantity of this flocculent matter appears to be 
greater towards the periphery of the cell, and, in fact, it would 
seem that the green bodies are at this time imbedded as it were 
in an amylaceous matrix, which they not improbably assimilate, 
because in the mature cell nothing of the sort is apparent. 

In the embryonic ]:)odies, however, or winter spores of 
V. aureus and st.ellatus, the presence of cellulose is rendered 
abundantly evident in the two coats forming the tunic of tlie 
spore by the blue colour produced in tliem by iodine and sul- 
phuric acid (fig. 11); nearly as distinctly, in fact, as it is in 
the tunic of Micrasterias and other Desmidica'. The aj)j)a- 
rently clear fluid between the two tunics is rendered brownish 



Busk on Volrox glohatur. 4 1 

and turbid at the same time (fi^s. 11, 12), and the solid con- 
tents of tlie interior are shown to consist, for the most part, of 
amylaceous grains of the peculiar botryoidal form above 
noticed. (Fig. 9.) The yellow oil-like fluid in the ripe 
spore acquires a green tint under the action of the same 
re-agents. (Fig. 9.) 



Appendix. — {October, 1852.) 

The above are the observations read at the Microscopical 
Society. I am now satisfied that they afford an account of 
but one of the multiform varieties under which Volvox occurs 
at different times and places. I must own also, that at the 
time my observations there detailed were made, I was unable 
to reconcile much of what I saw with some of the statements 
and figures in my friend Professor Williamson's ingenious 
paper on the same subject. Subsequent investigation, how- 
ever, and some correspondence with him, have satisfied me that 
I was hasty in drawing conclusions from one form only of a 
very protean object. I freely confess, that in much, in respect 
to which I had conceived Professor Williamson had fallen into 
some error of observation, he has been quite riglit, though at 
the same time I must say that his explanations of the appear- 
ances described and figured by him, do not exactly accord with 
my notions respecting them. I still maintain that the structure 
of the wall of Volvox — upon which alone I think we are dis- 
agreed — is essentially such as I have described it, viz., that it 
is formed by a continuous, external tunic, lined by the ciliated 
zoospores. Professor Williamson, on the other hand, as I 
understand him, conceives the globe to be " a hollow vesicle, 
the walls of which consist of numerous angular cells filled with 
green endochrome, &c., the intercellular spaces being more or 
less transparent." The ciliated zoospore, therefore, according 
to him, is not a mass of vegetable protoplasm, without dis- 
tinct wall, and precisely anah)goiis to a Euglena, or other 
naked zoospores, but represents the endochrome of a cell hav- 
ing two walls, an external and an internal, which latter is "a 
ductile cell-membrane, lining the interior of each cell and sur- 
rounding tlie cell-contents," and which " inner membrane be- 
comes separated from the outer cell-wall excepting at a few 
points, where it is retained in contact." And lie thus explains 
the mode of formation of the connecting filaments. In this 
case, therefore, these fdamcnts would never i)ass directly from 
one green mass to another, but would of course be interrupted 
in their course by the walls of two contiguous cells. That this, 



42 Busk on Volvox glohator. 

however, is not the case in the form of Volvox, which formed 
the subject of my paper, is sufficiently obvious. But it is 
nevertheless true, as I find from examination of Professor Wil- 
liamson's specimens, that his representation is, in certain cases, 
equally correct, as I shall afterwards explain. Another cir- 
cumstance also noticed by Mr. Williamson, and which, till he 
pointed it out particularly to me, had, though not altogether 
unnoticed, been disregarded, is the existence of delicate lines 
between the green granules, and dividing the wall of the Vol- 
vox into very regular hexagonal spaces, in the centre of each of 
which is placed one of the green granules. The former of these 
conditions— which, though I have never met with it myself 
distinctly in specimens from any other locality, seems to be 
sufficiently abundant in the neighbourhood of Manchester — is 
represented in figs. 15, 16, 17, 18, 19, 20. In these it will be 
seen that the central green body is surrounded, at variable dis- 
tances, by a tolerably thick, distinct membrane or wall, and 
that numerous irregular filaments, where they exist at all, 
extend from the central mass to this wall, and there terminate, 
and do not pass from one green mass to another, as in the 
usual form. Now, I explain the way in which the zoospore is 
thus modified, in this way : I regard the external membrane 
merely as the boundary-wall of the original zoospore, and, like 
the entire body, as composed of vegetable protoplasm ; and I 
believe that this peculiar appearance is produced by a great 
and unusual expansion of the interior of the zoospore (by 
endosmosis of fluid probably), by which the outer or periphe- 
ral layer is separated from the remainder and principal part of 
the mass, containing the chlorophyll and nucleus, or supposed 
nucleus, (5cc. Zoospores, in fact, in this condition might be 
said to be dropsical. That this separation of the wall from 
the contents arises in this way, and not, as Mr. W^illiamson 
says, from the shrinking of contents, is, I think, sufficiently 
obvious from several considerations, and is rendered very clear, 
if we trace the progressive stages of the hydropical enlarge- 
ment in one and the same Volvox, as I have done in the figures 
above cited. 

In this series it is easy to observe the earliest formation of 
the clear space up to the most extreme dilatation of which 
the cell is capable, owing to its contiguity with others. Of 
course when a number of cells are thus enlarged and mutually 
compressed, they assume an hexagonal form ; but this hexa- 
gonal arrangement must not, as it appears to me, be con- 
founded with another, to wliich I have before alluded, and 
which I conceive to be due to a different circumstance alto- 
gether. In fig. 15 of this series, some cells will be observed 



Busk on Volvox glohator. 43 

little if at all altered, from what I assume to be the normal 
form, and it will be seen that these little altered cells are 
mutually connected by the usual continuous filaments. In 
fig. 16 the zoospores are more expanded, and being in con- 
tact in many points, the connecting threads are absent ; 
fig. 17 shows a further degree of expansion, but more irregu- 
lar, and with irregular connecting filaments. In fig. 18 the 
enlargement is nearly as great as it can be, and numerous 
threads or processes of protoplasma extend from the central 
mass to the wall, just as they do in almost any vegetable cell 
from the nucleus to the primordial utricle, which utricle, in 
fact, is represented by the cell-wall in the case we are dis- 
cussing. In fig. I 9, the dilatation is complete, and, owing to 
the greater age of the specimen from which this figure was 
taken, the protoplasma is much wasted, and all the filamentary 
processes completely gone. A faint granular appearance 
occupies the cavity of the primordial cell. It is a curious 
fact, as showing perhaps that all the vital action in the cell 
resides in or around the nuclear mass, that not unfrequently the 
central mass after considerable expansion of the cell, and the 
formation in that way of one wall, will begin to throw off 
a second. This condition is represented in a more highly 
magnified drawing in fig. 20. 

Although I have not myself seen any natural specimens in 
which this condition of the zoospores was present, except those 
for which I have been indebted to Mr. Williamson, still I 
have repeatedly observed a partial appearance of the same 
kind to take place, when a specimen of Volvox of the normal 
sort is kept for some hours under observation in the micro- 
scope. Figs. 21, 22, 23 show the series of changes that 
took place in a certain number of zoospores watched at 
intervals, and left undisturbed for about twenty-four liours. 
(Fig. 21, 10 A.M., Oct. 4. Fig. 22, 1 p.m., Oct. 4. Fig. 22, 

8 A.M., Oct. 5.) 

Now with respect to the other form of hexagonal areo- 
lation, for my knowledge of which, as I have stated, 1 am 
chiefly indebted to Professor Williamson, and which is 
represented in figs. 24, 25, I have already observed, that I 
regard it as quite distinct from that produced by the mutual 
pressure of contiguous dilated zoospores. Professor William- 
son appears, from what he has told me by letter, to cons i( lei 
that this appearance is invariably present, or at all events that 
it can be elicited in all < ases by ajiprojjriati^ means. 1 must 
confess however, that I have not been successful in seeing it, 
or in producing it in very many instances, and tliat I hciievc it 
is occasionally impossible by any means to demonstrate its 



44 Busk on Volvox ghhator. 

existence. At some periods not a single specimen from a 
given locality will exhibit it, whilst at another, every indi- 
vidual will show it at the first glance. Thus in the month of 
August last, when, in a certain pond on Blackheath there was 
the most incredible abundance of Volvox, so great in fact as to 
render the water at the lee side of the pond in certain spots 
of a deep green colour, and to cause it to afford, when collected, 
a very strong herbaceous or confervoid smell, the majority 
of the plants exhibited the stellate form of spores, or rapidly 
acquired spores of that character, and very many were in, or 
soon assumed, the form of V. aureus. They seemed in fact to 
be entering upon their hybei'nating state. Many among them, 
however, though all small and starved-looking, were of the 
common kind ; in all these Air. Williamson's hexagonal areola- 
tion was very distinct. In the month of October, however, 
upon returning to the same pond, I was able to find very few 
Vohoces at all, and all of the usual kind ; in none of these could 
I detect the least appearance of the same arrangement. I there- 
fore conclude that the greater or less distinctness, or complete 
absence of this character, is to be referred to external condi- 
tions with which we are not fully acquainted. The appear- 
ance itself I explain in this way. It appears to me that each 
zoospore is imbedded in a distinct gelatinous or semi-fluid 
envelope of considerable thickness, and that the hexagonal 
areas are formed by the sides of these distinct masses of gelati- 
nous matter coming into contact. I am inclined to think that 
there is no distinct membrane containing this gelatinous matter : 
if there be, it must be infinitely thin, because the line of con- 
tact is extremely delicate and single. I conceive, in fact, that 
each ciliated zoospore is surrounded with a gelatinous or 
semi-fluid areola, of the same nature precisely as that which 
surrounds the embryo Volvox while within the parent, and 
in which also it is not I think possible to detect a distinct 
limitary membrane. This envelope of the ciliated zoospores 
contains a nitrogenous element, which sometimes, on the addi- 
tion of iodine, gives rise to the appearance of minute heads 
around the outer peripliery of each gelatinous mass, or in the 
lines of the hexagonal areas as seen in fig. 25. It is to be 
observed also, that connecting filaments of protoplasma may 
occasionally be seen to pass from one zoospore to another 
across the line of junction of the two gelatinous envelopes 
(fig. 24). These zoospores therefore of Volvox would appear 
to represent the " encysted zoospore " of Cohn {Profococcus 
pluvialis, 6cc.), and his fig. 43, plate 67, may perhaps be 
taken as a fair representation of what I conceive to be the 
(onditlon in these connected zoospores in Volvox. Tliis ex- 



Busk on Volvox glohator. 45 

planation of the hexagonal areolation, however, does not clash 
at all with tiiat which I have given as to the structure of the 
wall of Volvox. For in this case, as in all others, the collected 
mass of zoospores, and their envelopes, is enclosed by a con- 
tinuous external membrane, not in any way derived from them 
but from the parent cell in which they were originally formed. 
There are several other interesting points relating to Volvox 
which have come under my observation in a prolonged atten- 
tion to the subject, including another form of development of 
the internal spore, in which it divides, not in the usual way, 
into what may perhaps not inappropriately be considered as 
macrogonidia, to use Braun's expression, but into a much 
smaller and differently arranged sort, which may be considered 
as his microgonidia ; but to enter fully upon this and other 
points would demand more space than is here at command. 

[Whilst this paper is passing through the press, I have 
found that a faint, but quite distinct, purplish blue tinge may 
be produced in the wall of Volvox glohator by means of 
Schultz's solution. The specimens of Volvox in which I 
have noticed this have been preserved in glycerine for two 
months. — G. B.] 



Further Elucidations of the Structure of Volvox globator. 
By Professor W. C. Williamson. (Read June 21, 1852.) 

In May, 1851, I had the honour of laying before the Philo- 
sophical Society of Manchester a memoir on the Volvox gloha- 
tor* containing the results of a series of observations, which 
brought to light in that elegant object, a cellular structure, 
hitherto unobserved. Since the existence of these cells affects 
the character and affinities of the organism, it is desirable 
that the fact should be established beyond tlie possibility of 
dispute. My friend Mr. Busk, in a recent communication 
made to the Microscopical Society of London, eitlier doubts 
their existence, or rejects my ^dea of their cellular nature. 
This denial, coming from such a cjuarter, renders it incumbent 
upon me to make the matter more plain than was done in my 
previous memoir: I am enabled to do this, partly by new ob- 
servations on the living Volvox, and partly by some c-hanges 
which the specimens prepared last year l;ave^ undergone^, 
making their structure more obvious than it previously was. 

* Pubhshedin the Niuth Volume o^ its 'J'liinsactioiis. 



46 Williamson on Volvox glohator. 

No one who has seen these specimens can for a moment 
doubt that there exists immediately beneath the superficial 
pellicle, or common investing membrane of each Volvox^ a 
layer of closely-packed translucent vesicles, within each of 
which is located one of the numerous green spots ornamenting 
its periphery. In the memoir referred to, 1 endeavoured to 
show that tliese vesicles are true cells, whilst the green spots 
are the inner cell-membranes and their contents, representing 
the internal utricles of Harting and Mulder, the primordial 
utricles of Mirbel. The appearance of these cells in their 
different stages of growth was described, and the mode of 
their development and multiplication examined. 

Mr. Busk, who has recently directed his attention to this 
subject, has arrived at a different conclusion from my own, 
respecting the structures in question. Not having, then, seen 
the hyaline vesicles, which I regard as true cells, in any of his 
own specimens, he concluded that the Volvox consists of a 
number of protoplasms, which have resulted from the suc- 
cessive segmentations or subdivisions of one primary pro- 
toplasm, in the way described in my memoir. On being 
afforded an opportunity of examining some of my preparations 
of Volvox made last year, and in which the vesicles are re- 
markably distinct, though the appearance they presented was 
wholly new to him, he was still disposed to maintain his pre- 
vious opinion. Instead of admitting them to be true cells, 
he concluded that they were merely the outer layers of the 
protoplasmic segments, which, after separating from the pro- 
toplasmic mass, had become dropsically distended, and as- 
sumed the appearance of a true cell. 

Since I believe this general conclusion to be incorrect, I am 
anxious to render more clear than I have hitherto done, what 
appears to be the true interpretation of the structures in ques- 
tion. In accomplishing this, it will not be necessary to reca- 
pitulate all the details of my preceding memoir, since the 
accuracy of the greater number of them, as well as my con- 
clusion respecting tlie vegetable nature of Volvox, are con- 
firmed both by Mr. Busk and by other observers : some 
points, however, require to be examined in detail. 

There is (me point respecting wliich I was clearly in error ; 
my present correction of the mistake is due to the suggestions 
which I have received from Mr. Busk. I found that each 
young germ was developed from one of the perlj)heral stratum 
of cells, by tlie ordinary process of cell-division or segmenta- 
tion. Having ascertained that each protoplasm in its matured 
state was invested by a true external cell, in addition to a very 
thin inner one which held the grarmlar mass together, I con- 



Williamson o?i Volvox ghhator. 47 

eluded that, in the earlier stages of the process of segmentation 
and development of the germ, each protoplasmic segment 
would be invested by a similar external cell-membrane, as is 
the case with Hcematococcus, Palmella^ &c. I could not ascer- 
tain what became of these outer cells, as successive subdi- 
visions of tiieir contained protoplasms multiplied their number, 
but hazarded the surmise, that the earlier cells might either 
have been re-absorbed, or that they still existed in the form of 
thin membranes, consolidated with and investing the newer 
cells which I supposed had been developed within their in- 
terior. It is now obvious that none of the protoplasmic seg- 
ments have secreted their external cell-membrane, until the 
entire number destined to compose the matured organism has 
been completed. This interpretation accounts for many ano- 
malous circumstances. It explains the very close contact in 
which we find the green protoplasms of the immature germ. 
No transparent spaces intervene ; these only appear when the 
young germ is matured and furnished with cilia. It also 
explains my want of success in searching for the layers of 
cellulose, tlie residue of the supposed earlier-formed cells, 
which must have existed had the organism been developed in 
exactly the same way as a Palmella or an Hcematococcus. In 
these latter objects, each segmentation of the protoplasm is 
followed by the secretion of a true cell, which invests each 
segment. 

The point now to be demonstrated is the existence of two mem- 
branes surrounding each mass of protoplasm. First an inner 
one, very thin, and in the living state, closely embracing the gra- 
nular protoplasm, and corresponding with the inner cell-mem.- 
brane of the ordinary Confervae ; second, an outer cell-mem- 
brane secreted from the exterior of the first. To facilitate 
describing, we may term the former of these the protoplasmic 
membrane, and the latter the cell-membrane. 

The protoplasmic membrane is easily sliown to exist. Fig. 
6, PI. VI. represents a very young gemma, or budding germ, 
which consisted of but few segments, as it appeared when sub- 
jected to pressure under water. Some of the protoplasmic seg- 
ments glided through an aperture made in the common vesicl(>, 
without becoming ruptured. They accommodated themselves 
to the size and form of the aperture, and, on escaping, regained 
their spherical form. On increasing the pressure, each seg- 
ment burst, all the granular and mucilaginous contents flctwing 
out and mingling with the water (6 // ). As tliey did so the 
protoplasmic membranes (6 c) were distinctly seen as thin 
hyaline spheres. In the subsequent development of Volvox 
this membrane always continues in existence. Its appearanc*' 

VOL. I. '' 



48 Williamson on Volvox glohator. 

in the matured organism will be described immediately. When 
the gemma has attained its full size, by the process of segmenta- 
tion described in my former memoir, further changes occur. 
Translucent spaces separate the green protoplasms, now be- 
come hexagonal by mutual pressure. These translucent out- 
lines mark the development of the external cells investing the 
protoplasmic membranes. At first the two are in close oppo- 
sition ; they subsequently separate, as the cell increases in 
size, excepting at certain points where they remain in contact. 
Before tracing out the further stages of this process I must 
observe that the Volvox exhibits two apparently distinct states, 
which are, nevertheless, mere varieties of one species. In the 
one, each protoplasm assumes the appearance of fig. 1 b, being 
angular, and giving off thick, irregular and often dichotomous 
threads (1 c), the extremities of which are attached to the 
cell- wall (la). In this case, the radiating threads consist not 
only of the protoplasmic membrane, but also of its granular, 
mucilaginous contents. The other condition referred to is 
represented in fig. 10. Each protoplasm (10 (£) is perfectly 
spherical, and connected with its neighbours by delicate capil- 
lary threads, these being so fine as to be sometimes almost 
invisible. In this state the cells to be described are often 
invisible ; nevertheless, they exist. 

The changes undergone by the stellate variety were described 
in my previous memoir. The cell expands, and as the pro- 
toplasm is only attached to it at certain points, the latter is 
drawn out until it finally assumes the stellate contour deli- 
neated in fig. 1. Each of the radiating threads is attached to 
the cell- membrane by its peripheral extremity, at a point 
exactly opposite the corresponding threads of contiguous pro- 
toplasms. On rupturing a Volvox under water these threads 
become detached from the cell- wall, and passing through the 
stages represented in figs. 2 and 3, assumed that of fig. 4, 
which is precisely that of fig. 10, minus the connecting threads, 
a state which occasionally occurs in the living Volvox. 

In numerous examples of both these varieties of Volvox 1 
found each protoplasm surrounded by an angular, usually 
hexagonal, areola, as represented in fig. 5 of my original me- 
moir. They appeared as dark outlines when the object was 
illuminated by transmitted light. On exposing these speci- 
mens for a while to the action of some re-agents, as glycerine, 
I soon found that each dark line was really double, and marked 
the boundaries of two cells. This was shown by the gradual 
separation of these cells at the angles of the areolae, as repre- 
sented in fig. 11, which is a faithful transcript of part of one 
of these specimens when mounted in glycerine. In this ex- 



Williamson on Volvox glohator. 49 

ample no cells were at first visible ; but as I watched them, they 
came gradually into view in some parts of the organism, but 
not in others. Fig. 11 represents a portion of it, in the upper 
part of which the cells are visible, whilst in its lower part 
they cannot be traced ; here the tissues were transparent and 
apparently quite structureless, as was the entire sphere in the 
first instance. The transition from the one condition to the 
other was gradual ; the dark lines becoming less conspicuous 
and finally disappearing as we approached the opposite side of 
the Volvox to that on which they were most distinct. This 
specimen illustrates thousands that have been examined, and 
proves that the apparent absence of the cells from so many of 
the objects is no proof that they do not exist, but merely shows 
that certain favourable conditions are required to bring them 
into view. We are justified in concluding that they exist alike 
in all the specimens of Volvox, and are not merely accidental 
developments in a few individuals. 

In my mounted preparations we obtain further evidence 
respecting the nature of these two membranes — the proto- 
plasmic and the cellular. We see that the wall of the sphere 
has an appreciable thickness, the inner margin being as 
definite as the outer one, and nearly parallel with it. Fig. 5 
represents this as seen in a section of a Volvox. A moment's 
inspection of my preparations would convince the most 
sceptical that such is the case ; several of these peripheral 
cells, as seen in the section, are more highly magnified in 
figs. 14 and 1.5. The thin investing pellicle (15 d) com- 
presses the outer wall of each cell into conformity with the 
peripheral curve of the sphere; laterally the septa (15 a) are 
straight and parallel to one another. Internally, each cell is a 
little turgid (15 a), the centripetal pressure at this point being 
obviously at the minimum, and allowing tlie primary tendency 
of the cell to assume a spherical form to manifest itself. The 
green protoplasm adheres firmly to the peripheral wall of each 
cell, through which the cilia are protruded. Between the 
true cell-wall and the protoplasm, we have the protoplasmic 
membrane (14 and 15 cc') in variable conditions. Some- 
times it forms an oval cell (14 c'), sometimes it is oval at one 
end and flattened out at the other (14c, 15c') ; at others it is 
not only flattened out at each extremity and in close oi)posi- 
tion with the cell-wall, but even at the two sides (as in the 
centre cell of fig. 15) the two membranes are closely ap- 
proximated. 

If we turn to a superficial view of the same specimens, we 
shall obtain similar results. It must be borne in mind tliat 
in the living Volvox, even where the cells are visible, wo only 

e 2 



50 WirxiAMSON c.>i Volvox glohator. 

see the true cells ; the protoplasmic membrane being in such 
close apposition to its granular and mucilaginous contents as 
to prevent its being identifi