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TUB
MICROSCOPIC ANATOMY
OF
THE HUMAN BODY,
IN
HEALTH AND DISEASE,
ILLUSTRATED WITH NUMEROUS DRAWINGS IN COLOUR.
BY
ARTHUR HILL HASSALL, ffl. B.
Author of a " History of the British Fresh-water Algae;" Fellow of the Liimajan Society; Member of the
Royal College of Surgeons of England ; one of the Council of the London Botanical Society ;
Corresponding Member of the Dublin Natural History Society. &c.
ADDITIONS TO THE TEXT AND PLATES,
AND
AN INTRODUCTION,
CONTAINING INSTRUCTIONS IN MICROSCOPIC MANIPULATION,
BY
HEJVRY VANARSDALE, M. D.
IN TWO VOLUMES.
VOL. I.
NEW-YOEK;
PRATT, WOODFORD & CO.
BOSTON : TICKNOR, REED, & FIELDS ; PHILADELPHIA : L1PPINCOTT GRAMBO & CO.
CINCINNATI : H. W. DERBY & CO. ; HARTFORD : E. C. KELLOGG
18 51.
.ML?-
/rr/
ENTERED, ACCORDING TO ACT OF CONGRESS, IN THE YEAR 1851, BY
E. C. KELLOGG,
IN THE CLERK'S OFFICE OF THE DISTRICT COURT OF CONNECTICUT.
>
FOUNDRY OP
PRESS or
SILAS ANDRTTS AND SON,
F. C. GUTIERREZ,
HARTFORD.
HEW-T03K.
TO
THOMAS WAKLEY, ESQ., I. P.,
CORONER, ETC., ETC.
Dear Sir:
To you I dedicate the accompanying pages, devoted to
the elucidation of a department of minute anatomy of daily
increasing interest and importance.
I thus dedicate this work to you on two grounds; the
one personal and private, the other public.
On my mentioning the design of this work to you — and
you were one of the first persons to whom it was mentioned
— you were kind enough to express yourself in terms of
approval and encouragement, and to proffer any assistance
in your power in the furtherance of my undertaking. Of
this conduct on your part I have ever entertained a pleasing
and grateful remembrance; and it is this which constitutes
the private ground of my dedication.
But I dedicate this work to you on a higher and more
important ground. I have for many years seen in you the
DEDICATION,
able and strenuous advocate — amidst much obloquy and
misrepresentation — of the rights of that profession of which
we are both members: on this high ground I conceive you
to be entitled to the gratitude of your professional brethren;
and with this feeling on my mind of your conduct and
services in a good cause,
I beg to subscribe myself,
Yours, very faithfully,
THE AUTHOR.
PREFACE TO THE ENGLISH EDITION.
After three years of more or less constant labour, the welcome and often-wished-
for period of the completion of this work has arrived, and the author is at liberty to
address himself to his readers, and to explain the motives and the circumstances
which have led to its production.
The idea of this work presented itself to the author's mind several years since ; it
was not, however, until about the period above referred to, that its actual execution
was commenced.
At the time when its design was first conceived, the powers of the microscope in
developing organic structure were but beginning to be known and appreciated, and
the importance of its application to physiology and pathology was but dimly perceived.
At that period, also, but few complete works devoted to microscopic anatomy had
appeared in any language, native or foreign; more recently this deficiency, as res-
pects France and Germany, has been well supplied by the appearance of several
original works, as those of Donne, Mandl, Lebert, Miiller, Henle, Vogel, Gerber, and
Wagner; England, however, has not as yet contributed her share of distinct and
independent works on general anatomy : not that our observers have been idle, or
have neglected a field of inquiry so interesting and important, resting satisfied with
mere translations: a whole host of intelligent and able microscopists have applied
themselves to the investigation of the ultimate structure of the several tissues and
organs, and this with a preeminent degree of success. Among the more remarkable
of these investigators, the following may be enumerated: Gulliver, Martin Barry,
Busk, Addison, Kiernan, Sharpey, Goodsir, Tomes, Toynbee, Johnson, Simon, Todd
and Bowman, Quekett, Erasmus Wilson, Hughes Bennet, Carpenter, Rainey, Hand-
held Jones, and Gairdner.
The results of the labours of these observers have. not as yet, however, been
embodied in a separate work ; but some of them have been mixed up with works on
descriptive anatomy and physiology, as in Sharpey's edition of Quain's Anatomy, in
Carpenter's " Principles " and " Manual " of Physiology, and in Todd and Bowman's
" Physiological Anatomy." The last is an admirable book, full of original research
and important facts.
Now, one of the purposes, the accomplishment of which has been attempted in the
following pages, has been the collecting together of the numerous communications
on general anatomy to be found scattered through the pages of our different scientific
periodicals, and their combination into a whole.
The further objects which the author has had in view in the production of this
work have been simplicity of description, fidelity of representation, and the addition
of such facts and particulars as have occurred to himself in the course of his own
investigations; and he may take this opportunity of observing, that in but few
instances has he written upon a subject without previous investigation.
6 PREFACE TO THE ENGLISH EDITION.
The author considers it right, in justice to himself, that certain disadvantages under
which the work has been produced should be mentioned : these were, constant
engagement in general practice, much anxiety, and, though last, not least, ill health.
These would have been sufficient to have deterred many from the undertaking alto-
gether. Although this has not been the effect upon the author, yet it cannot be
questioned but that they have operated in some respects to the disadvantage of the
work ; and he begs that it may be taken neither as the measure of that of which
the subject is capable, nor of the author's powers of observation and description
exercised under more favourable circumstances of health, leisure, and feeling.
The author makes these few remarks not in order to deprecate any fair criticism,
but simply that the truth in reference to the production of this work may be known
in justice both to the writer and the reader.
Having said thus much in relation to the work itself, the author has now the
pleasing task of returning his acknowledgments to those who have in any way
assisted him in his laborious though most agreeable task; these are particularly due
to the following: Mr. Quekett, Dr. Handfield Jones, Professor Sharpey, Mr. Tomes,
Mr. Bowman, Mr. Busk, Professor Owen, Mr. Canton, Dr. Carpenter, Dr. Letheby,
Dr. Robert Barnes, Mr. Ransom, Mr. Pollock, and Mr. Gray, of St. George's Hospital,
Mr. Hett, and Mr. Andrew Ross: they are also due to Mr. Drewry Ottley; Dr. Rad-
cliffe Hall; Mr. Coppin, of Lincoln's Inn; Messrs. Welch and Jones, of Dalston;
Mr. Berry, of James-street, Covent Garden ; Mr. Cowdry, of Great Torrington ; Dr.
Jones, of Brighton; Dr. Chambers, of Colchester; Mr. Milner, of Wakefield; Mr.
Walker, of St. John's-street Road; Mr. Ringrose, of Potter's Bar; Dr. Halpin, of
Cavan ; and Mr. H. Hailey, of Birmingham.
To Dr. Letheby I hope shortly to have a second opportunity of rendering my
thanks, in connexion, viz: with the work on crystals, entitled "Human Crystallo-
graphy," an announcement of which appeared some months since, and towards the
completion of which considerable materials have already been collected.
To Mr. Hett, my thanks are especially due for having, at considerable trouble and
inconvenience, furnished me with very many of the injections required to illustrate
Part XV. of the "Microscopic Anatomy;" these, together with numerous other
injected preparations of that gentleman which I have seen, have been of first-rate
quality; and the microscopic anatomist has reason to hail the advent of such a man
to the cause of general anatomy with the highest satisfaction.
To Mr. Andrew Ross, on this, as on a former occasion, I have to express my obli-
gations, Mr. R. having at all times furnished me with any information I might require,
as well as provided me with any necessary apparatus.
Thus much for friends. If, in the inditing of this work, I have made a single
enemy, I am sorry for it, and still more so if I have given any real occasion for offence.
If, in differing from other observers as to certain facts and conclusions, I have
expressed myself in such a manner as to wound their feelings, as in one or two
instances I fear I may have done, I much regret it: the differences among men whose
common aim is the knowledge of truth, as manifested in the works of creation, should
never be deep or lasting; for this community of purpose should ever be a firm bond
of union between such men, seekers after truth, and should displace from their minds
the lesser and grosser feelings of rivalry and ill-will.
Nottino Hill, July 27th, 1849,
PREFACE,
BY THE AMERICAN EDITOR,
The Microscopic Anatomy of Dr. A. H. Hassall is offered to the student in this
department of Medical Science, as the only completed work on the subject in the
English language.
In the present edition, the introduction and additions to the text, are chiefly of a
practical nature; this feature, it is hoped, will not detract from the high scientific
character of the original work, but will give it some additional value for those who
wish to pursue the study of minute anatomy, by the aid of the microscope.
It will be observed that, in some instances, Dr. Hassall's views differ from those of
other writers. Some of these views Dr. Hassall has himself modified, and made
mention of the fact in the Appendix : other instances of difference have been pointed
out by the editor; others, again, and these are chiefly matters of opinion on disputed
points, have not been alluded to, as it did not seem desirable to extend the work, by
adducing farther conflicting statements on unsettled questions.
The ten Plates added to the American edition, are mostly original, and from the
human subject. The drawings for these Plates were made by aid of one of Mr.
Spencer's excellent microscopes, which was obligingly loaned for the purpose by
Prof. C. R. Gilman.
For some of the specimens illustrating certain points of anatomy which have been
figured, the editor is indebted to Mr. Hett, of London, so well known to micro-
scopists for his beautiful preparations of healthy and diseased structures. For
other objects of value, to Drs. Neill and Goddard of Philadelphia, whose minute
injections have equalled the best foreign ones.
Almost all the drawings were made by Mr. W. R. Lawrence of Hartford, whose
previous experience in drawing from the microscope, contributed greatly to the
8 PREFACE BY THE AMERICAN EDITOR.
accurate representations he has given. Several of the figures in Plates LXXIV.
and LXXV., were drawn by Mr. H. A. Daniels, who is well known to the profes-
sion of this city as an accomplished anatomical draughtsman.
To all these gentlemen, as well as to Prof. A. Clark, and A. S. Johnson, Esq.,
of New-York, for valuable hints in manipulation; and, lastly, to the publishers,
for the generous manner in which they allowed the expensive additions, and for
the excellent style in which they have issued the work, the editor desires to tender
his acknowledgments.
The additions to the text are inserted at the end of the Articles, and enclosed
in brackets.
New-York, 112 West Twenty-Second Street, )
May 1st, 1851. ^
CONTENTS.
INTRODUCTION.
PAGE
Its Object 27
Choice of a Microscope 27
Division of Subject 27
I. — MICROSCOPES AND THEIR ACCESSORIES.
Ross' Microscope 29
Powell and Lealand's ditto 29
Smith and Beck's ditto 30
Chevalier's ditto 30
Oberhauser's ditto 30
Brunner's ditto ........."••• 31
Nachet's ditto 31
Spencer's ditto 31
Allen's ditto 33
Pike and Sons' ditto 33
Accessory Instruments 33
II,— PREPARATION OF OBJECTS.
Of Fluids . . 37
Of Solids . 38
Fine Injections 42
Materials, used in 42
General Directions 42
Injections with Turpentine . . 42
Ditto with Ether 43
Ditto by Double Decomposition 44
Ditto with other Materials 48
III.— PRESERVATION OF OBJECTS.
Different Cements used 49
Glass Slides and Cells 51
Thin Glass . 51
10 CONTENTS.
PAGE
Thin-glass Cells 54
Drilled ditto 54
Tube ditto 54
Built-up ditto 55
Gutta-percha ditto 55
FLUIDS FOR MOUNTING OBJECTS.
Alcohol and Water 56
Goadby's Solutions 56
Other Fluids . ... . . 57
METHODS OF MOUNTING OBJECTS.
The dry way 59
In Canada Balsam with heat 60
In Fluid 62
As Opaque Objects ' . . . 63
Labelling Slides 63
Cabinets . .... 64
PART I.
FLUIDS OF THE HUMAN BODY.
ARTICLE I.
The Lymph and Chyle. — General description of Lymphatics and Lacteals, page 67.
Characters and Structure of Lymph, 68. Ditto of Chyle, 68. Ditto of Fluid of
Thoracic duct, 70. Corpuscles of Thymus, 72. Structure of Lymphatics, 76.
Examination of Lymph and Chyle, 78.
ARTICLE II.
The Blood. — Definition, 80. Coagulation of the Blood, without the Body, 80.
Formation of the Clot, 81. Formation of the Buffy Coat of the Blood, 83. Cup-
ping of the Clot, 85. Coagulation of the Blood in the Vessels after Death, 86.
Signs of Death, 86. Globules of the Blood, 88. The Red Globules, 89. The
White Globules, 100. Molecules of the Blood, 121. Blood Globules of Reptiles,
Fishes, and Birds, 123. Capillary Circulation, 125. Circulation in the Embryo of
the Chick, 129. Venous and Arterial Blood, 134. Modifications of the Blood
Corpuscles the results of different external Agencies, 138. Modifications, the
results of Decomposition occurring in Blood abandoned to itself without the Body,
139. Modifications, the results of Decomposition occurring in Blood within the
CONTENTS. 11
Body after Death, 139. Causes of Inflammation, 140. Pathology of the Blood,
142. Importance of a Microscopic Examination of the Blood in Criminal Cases,
164. Examination of, 169. Preservation of, 170.
ARTICLE ill.
Mucus, 171. General characters, 171. Mucous Corpuscles, 174. Nature of Mucous
Corpuscles, 176. The Mucus of different Organs, 179.
ARTICLE IV.
Pus, 183. General characters, 183. Identity of the Pus and Mucous Corpuscle, 183.
Distinctive characters of Mucus and Pus, 186. Distinctions between certain forms
of Mucus and Pus, 190. Detection of Pus in the Blood, 191. False Pus, 192.
Metastatic Abscesses, 193. Venereal Vibrios, 194.
ARTICLE V.
Milk, 195. Serum of the' Milk, 196. The Globules, 197. Colostrum, 201. Patho-
logical Alterations of the Milk, 203. The Milk of Unmarried Women, 206. The
Milk of Women previous to Confinement, 206. The Milk of Women who have
been delivered, but who have not nursed their Offspring, 208. Milk in the Breasts
of Children, 208. Different kinds of Milk, 208. Good Milk, 210. Poor Milk,
212. Rich Milk, 213. Adulterations of Milk, 213. Formation of Butter, 214.
Modifications of Milk abandoned to itself, and in which Putrefaction has com-
menced, 215. The Occurrence of Medicines, &c. in the Milk, 217. Examination
of Mucus, Pus, and Milk, 217.
ARTICLE VI.
The Semen, 218. Spermatozoa, Form, Size and Structure of, 218. Motions of the
Spermatozoa, 225. Spermatophori, 228. Development of the Spermatozoa, 229.
The Spermatozoa essential to Fertility, 232. Pathology of the Seminal Fluid, 234.
Application of a Microscopic examination of the Semen to Legal Medicine, 237.
Examination of Semen, 239.
ARTICLE VII.
Saliva, Bile, Sweat, Urine, 240. The Saliva, 241. The Bile, 242. The Sweat,
243. The Urine, 245. Pathology of the Urine, 246. Examination of Urine, 252.
12 CONTENTS.
PART II.
SOLIDS OF THE HUMAN BODY.
ARTICLE Y III.
Fat, 254. Form, Size, and Structure of the Fat Corpuscle, 254. Distribution of
Fat, 259. Disappearance of, 261. Injection of Fat-vesicles, 263.
ARTICLE IX.
Epithelium, Distribution of, 264. Tesselated Epithelium, Structure of, 265.
Conoidal Epithelium, naked and ciliated, Structure of, 267. Development and
Multiplication of Epithelium, 271. Nutrition of Epithelium, 272. Destruction
and Renewal of Epithelium, 272. Epithelial Tumours, 275. Examination of
Epithelium, 275.
*
ARTICLE X.
Epidermis, Distribution, Form, Structure, and Development of, 277. Epidermis of
the White and Coloured Races, 279. Destruction and Renewal of Epidermis,
279. Description of, according to Mr. Rainey, 281. Examination of, 281.
article xi.
The Nails, Structure of, 282. Development of, 283. Examination of, 258.
article xii.
Pigment Cells, Structure and Varieties of, 286. Study of, 290.
article XI II.
Hair, Form of, 291. Size of, 292. Structure of, 292. Growth of, 297. Regen-
eration of, 297. Nutrition of, 299. Distribution of, 300. Colour of, 301.
Properties of, 302. The Hair of different Animals, 303. Method of making
thin sections of, 305.
article XIV.
Cartilages, 306. True Cartilages, 306. Fibro-Cartilages, 309. Nutrition of Car-
tilage, 311. Growth and Development of Cartilage, 312. Study of Cartilage, 316.
article XV.
Bone, Structure of, 317. Growth and Development of, 324. Accidental Ossification,
332. Preparation of Bone, 334.
CONTENTS,
ARTICLE XVI.
13
Teeth, Structure of, 335. Development of, 339. Caries of, 344. Tartar on, 345.
Method of making sections of, 345.
ARTICLE XVII
Cellular or Fibrous Tissue, 346. Inelastic or White Fibrous Tissue, 346. Elastic
or Yellow Fibrous Tissue 348 Development of Fibrous Tissue, 352.
ARTICLE XVIII.
Muscle, 354. Structure of Muscle, 355. Structure of the Unstriped Muscular
Fibrilla, 355. Structure of the- Striped Muscular Fibre, 357. Union of Muscle,
with Tendon, 362. Muscular Contraction, 363. Development of Muscle, 367.
Prof. Kolliker on Unstriped Muscle, 371. Mode of preparing for examination, 375.
article XIX.
Nerves, 376. Structure of, 376. Cerebro- Spinal System. Secreting or Cellular
Structure of, 376. Tubular Structure of, 378. Sympathetic System, 380. Gelatin-
Nerve, Fibres of, 380. Structure of Ganglia, 383. Origin and Termination
of Nerves, 384. Pacinian Bodies, 386. Development and Regeneration of Nerv-
ous Tissue, 388. Researches of M. Robin, 391. Preparation of, for examination, 394.
ARTICLE XX.
Organs of Respiration, 395. Aeriferous Apparatus. Bronchial Tubes, and Air-
Cells, 395. Vascular Apparatus, 398. Pathology, 399. Mr. Rainey's views on,
404. Examination of, 405.
ARTICLE XXI.
Glands, 406. Classification of Glands, 408. a. Follicles, 410. Stomach Tubes, 412.
Fallopian and Uterine Tubes, 413. Solitary Glands, 413. Aggregated Glands,
414. B. Sebaceous Glands, 414; comprising the Meibomian Glands, 416. Glands
of Hair Follicles, 416. The Caruncula Lachrymalis, 418. Glands of Nipple, 418,
and Glands of Prepuce, 418. Mucous Glands, 418; including the Labial, Buccal,
Lingual, Tonsilitic, Tracheal, and Bronchial Glands; also, the Glands of the
Uvula, Brunner's and Cowper's Glands, 418. Brunner's Glands, 421. Coivper's
Glands, 421. c. Salivary Glands, 422. Lachrymal Glands, 423. Mammary
Glands, 423. Liver, Structure of, 423. Pathology of, 432. Examination of, 435.
Prostate Gland, 436. d. Sudoriparous Glands, 437. Structure and examination
of, 439. Axillary Glands, 441. New Tubular Gland in Axilla, Plate LVIL, fig.
4 b. Ceruminous Glands, 441. Kidneys, 442. Secreting Apparatus of, including
Tubes, Malpighian Bodies, and Epithelial Cells, 442. Vascular Apparatus of, 444.
Development of the Kidney, 449. Pathology of, 453. Examination of, 482.
14 CONTENTS.
Testis, 483. E. Thymus Gland, 484. Thyroid Gland, 486 Supra-renal Capsules,
488. Spleen, 489. i\ Absorbent Glands, 492. Villi of the Intestines, 493.
Examination of, 496.
ARTICLE XXII.
Organs of the Senses, 497. Touch: .Papillary Structure of the Skin, 497.
Examination of, 500. Taste : Papillary Structure of the Mucous Membrane of
the Tongue, 501. Smell: Structure of the Mucous Membrane of the Nose, 505.
Vision: Structure of the Globe of the Eye, 509. Sclerotic, 509. Cornea, 510.
Choroid, 514. Retina, 518. Vitreous Body, 521. Crystalline Lens, 522. Dissec-
tion of the Eye, 533. Hearing: Organ of, 523 External Ear, 523. Middle
Ear, 523. Internal Ear, 525.
APPENDIX.
Pituitary Gland, 535. Pineal Gland, 536. Pia Mater, 537. Pacchionian Glands,
538. Development of the Fat Vesicle, 538. On the Structure and Formation of
the Nails, 541. On the Ganglionic Character of the Arachnoid Membrane, 543.
Structure of the Striped Muscular Fibrilla, 547. Structure of the Bulb of the
Hair, 547. Synovial Fringes, 547. Structure of the Sudoriparous Glands, 547.
IN-DEX OF THE ILLUSTRATIONS,
THE WHOLE OF THE FOLLOWING ILLUSTRATIONS AKE
ORIGINAL WITH BUT NINE EXCEPTIONS:
BLOOD.
Corpuscles of man, the red with the centres clear, 670 diam
The same, the red with the centres dark, 670 diam.
The same, seen in water, 670 diam. .
The same, the red united into rolls, 670 diam.
Tuberculated condition of the red corpuscles, 670 diam
White corpuscles of man, in water, 670 diam.
Corpuscles of frog, 670 d'iam. ....
The same, with the nucleus of the red visible, 670 diam.
The same, in water, 670 diam.
The same, after prolonged action of water, 670 diam
Nuclei of red corpuscles of frog, 670 diam.
Elongation of red corpuscles of ditto, 670 diam.
Corpuscles of the dromedary, 670 diam.
The same of the siren, 670 diam. ....
The same of the alpaco, 670 diam.
The same of the elephant, 670 diam.
The same of the goat, 670 diam.
Peculiar concentric corpuscles in blood, 670 diam. .
Coagulated fibrin, 670 diam. ....
The same with granular corpuscles, 670 diam.
Corpuscles of earth-worm, 670 diam.
Circulation in tongue of frog, 350 diam.
The same in web of the foot of ditto, 350 diam.
Corpuscles in vessels of the same, 670 diam. .
White corpuscles in vessels of the same, 900 diam.
Glands of tongue of frog, 130 diam.
Under surfaee of tongue of same, 500 diam.
Red corpuscles of embryo of fowl, 670 diam.
The same, in water, 570 diam. . . .
Red corpuscles of adult fowl, 670 diam.
The same of young frog, 670 diam.
The same of the adult frog, 670 diam.
The same united into chains, 670 diam.
I.
Fig
. 1
I.
"
2
I.
"
3
I.
"
4
I.
it
5
I.
"
6
II.
«
1
II.
"
2
II.
"
3
II.
"
4
II.
"
5
II.
"
6
III.
it
1
III.
"
2
III.
"
3
IV.
•'
1
IV.
"
2
IV.
"
3
IV.
"
4
IV.
"
5
IV.
St
6
V.
ts
1
V.
"
2
VI.
t<
1
VI.
"
2
TO.
"
1
VII.
"
2
IX.
"
1
IX.
"
2
IX.
«
3
IX.
«
4
IX.
"
5
IX.
«
6
16
INDEX OF THE ILLUSTRATIONS.
DEVELOPMENT OF EMBRYO OF CHICK.
The cicatricula prior to incubation
The same at the end of first day of incubation
The same at the thirty-sixth hour .
The same at the close of the second day
The same at the end of the third day
The embryo on the conclusion of the fourth day
The same at the termination of the fifth day
The embryo of six days old ....
The embryo of the ninth day of development. .
The same at the end of the seventh day, detached
Ditto at the end of the ninth day, also detached
Plate
X.
Fig. 1
<<
X.
" 2
"
X.
" 3
« •
X.
" 4
"
X.
" 5
«
X.
" 6
a
X.
« 7
"
X.
" 8
"
X.
" 9
«
X.
" 10
a
X.
« 11
MUCUS.
Corpuscles of, in their ordinary condition, 670 diam.
The same collapsed, 670 diam
The same, showing the action of water, 670 diam.
The same acted on by dilute acetic acid, 670 diam.
The same after the action of undilute acetic acid, 670 diam.
The same in process of development, 670 diam.
Vaginal mucus, 670 diam. ......
^Esophageal mucus, 670 diam. .....
Bronchitic ditto, 670 diam.
Vegetation in mucus, 670 diam. .....
Mucus of stomach, 670 diam .
Vaginal tricho-monas
PUS.
Corpuscles of laudable pus, 670 diam. .
The same acted on by acetic acid, 670 diam. . .
The same treated with water, 670 diam
Epithelial scales from pustule, 670 diam. . . .
Corpuscles from scrofulous abscess, 670 diam. . . ,
Vibrios in venereal pus, 670 diam. ....
XI.
tc
1
XI.
ft
2
XI.
"
3
XI.
"
4
XI.
"
5
XI.
it
6
XII.
"
1
XII.
"
2
XII.
"
3
xn.
ft
4
XII.
tt
5
XII.
«
6
xrri.
« 1
xni.
« 2
XIII.
< 3
XIII.
< 4
xni.
' 5
xin.
< 6
MILK.
Globules of healthy milk of woman, 670 diam. .
The same of impoverished human milk, 670 diam.
Colostrum, 670 diam. .....
Ditto, with several corpuscles, 670 diam.
Globules of large size, 670 diam.
Ditto, aggregated into masses, 670 diam.
Pus in the milk of woman, 670 diam.
Blood corpuscles in the human milk, 670 diam.
Globules after treatment by ether, 670 diam.
The same after the application of acetic acid, 670 diam.
XIV.
' 1
xiv. " 2
XIV.
' 3
XIV.
« 4
XIV.
« 5
XIV.
' 6
XV.
< 1
XV.
' 2
XV.
< 3
XV.
' 4
INDEX OF THE ILLUSTRATIONS,
17
Caseine globules, 670 diam Plate xv. Fig. 5
Milk of cow adulterated with flour, 670 diam. .... " xv. " 6
SEMEN.
Spermatozoa and spermatophori of man, 900 diam.
Spermatozoa of Certhia familiaris .....
FAT.
The fat vesicles of a child, 130 diam. .
Ditto of an adult, 130 diam. ......
Ditto of the pig, with apparent nucleus, 130 diam.
Ditto of the same, ruptured, 130 diam. ....
Ditto of marrow of the femur of a child, 130 diam. .
Ditto, with the membranes of the vesicles ruptured, 130 diam.
Crystals on human fat vesicles, 130 diam. ....
Fat vesicles in melicerous tumour, 130 diam.
Ditto contained in parent cells, 120 diam. ....
Ditto after the absorption of the parent cell-membrane, 120 diam.
EPITHELIUM,
XVI.
XVI.
Buccal epithelial cells, 670 diam. ....
Cuneiform ditto from duodenum, 670 diam.
Ciliary epithelium from trachea of frog, 670 diam.
Human ciliary epithelium from lung, 670 diam.
Ditto from trachea, 670 diam. .
Tesselated epithelium from tongue of frog, 670 diam.
Ditto from tongue of triton, 670 diam.
Ditto from serous coat of liver, 670 diam.
Ditto from choroid plexus, 670 diam.
Ditto from vena cava inferior, 670 diam.
Ditto from arch of the aorta, 670 diam.
Ditto from surface of the uterus, 670 diam. .
Ditto from the internal surface of the pericardium, 670 diam
Ditto of lateral ventricles of brain, 670 diam.
Ditto of mouth of menobranchus lateralis, 670 diam.
EPIDERMIS.
Upper surface of epidermis, 130 diam.
Under surface of ditto, 130 diam
Epidermis of palm, viewed with a lens only,
Ditto, magnified 100 diam. ......
Vertical section of ditto, 100 diam. ....
Ditto of one of the ridges, 100 diam. .
Epidermis from back of hand, viewed with a lens
A portion of same more highly magnified, 100 diam.
Epidermis from back of hand 100 diam.
Ditto, viewed on its under surface, 100 diam.
Portion of ditto, with insertion of hairs, 100 diam.
2
XVIII.
" 1
XVIII.
" 2
XIX.
" 1
XIX.
" 2
XIX.
" 3
XIX.
" 4
XIX.
" 5
XIX.
" 6
LXIX.
" 10
LXIX.
" 11
XX.
" 1
XX.
" 2
XXI.
« 1
XXI.
" 2
XXI.
" 3
XXI.
" 4
XXI.
" 5
XXII.
" 1
XXII.
" 2
XXII.
" 3
XXII.
« 4
XXII.
" 5
XXII.
" 6
XXVI.
"6e
XXVI.
"6d
XXIII.
" 1
XXIII.
« 2
XXIV.
" 1
XXIV.
« 2
XXIV.
« 3
XXIV.
' 4
XXIV.
t 5
XXIV.
< 6
XXVI. " 1
xxvi. " 2
XXVI. '
< 3
18
INDEX OF THE ILLUSTRATION
Ditto from back of neck, 670 diam.
Detached cells of epidermis, 670 diam.
Cells of vernix caseosa, 130 diam.
Cells of ditto, 670 diam.
Plate xxvi. Fig. 5
" xxvi. "6a
" xxvi. "6b
" xxvi. "6c
NAILS.
Longitudinal section of nail, 130 diam
Ditto, showing unusual direction of striae, 130 diam.
Ditto, with different distribution of striae, 130 diam.
Transverse section of nail, 130 diam. . . . .
Cells of which the layers are formed, 130 diam. and 670 diam.
Union of nail with true skin, 100 diam. .
PIGMENT CELLS,
Cells of pigmentum nigrum (human), 760 diam. " xxvu.
Ditto of the same of the eye of a pig, 350 diam " xxvu.
Stellate cells of lamina fusca, 100 diam " xxvu.
Ditto more highly magnified, 350 diam. " xxvu.
Cells of skin of negro, 670 diam " xxvu.
Ditto from lung, 670 diam " xxvu.
Cells in epidermis of negro, 350 diam " xxvu.
Ditto in areola of nipple, 350 diam " xxvu.
Ditto of bulb or hair, 670 diam " xxvm.
HAIR.
Bulb of hair, 130 diam. ....
Root of a gray hair, 130 diam.
Cells of outer sheath, 670 diam.
Portion of inner sheath, 350 diam.
Stem of gray hair of scalp, 350 diam.
Transverse section of hair of beard, 130 diam.
Another section of the same, 130 diam.
Fibres of the stem of the hair, 670 diam.
Apex of hair of perineum, 350 diam.
Ditto of scalp, terminating in fibres, 350 diam. .
Ditto of same with needle-like extremity, 350 diam
Root of hair of scalp, 130 diam.
Another form of same, 130 diam. .
Hair with two medullary canals, 130 diam.
Insertion of hairs in follicles, 100 diam.
Disposition of hairs on back of hand.
CARTILA 6E.
Transverse section of cartilage of rib, 350 diam.
Parent cells seen in section of ditto, 350 diam.
Vertical section of articular cartilage, 130 diam.
Ditto of inter- vertebral cartilage, 80 diam.
Cartilage of concha of ear, 350 diam. .
XXV.
' 1
XXV.
< 2
XXV.
' 3
XXV.
< 4
XXV.
' 5
XXVI.
' 4
I
' 2
3
'4a
'4b
'4c
' 5
' 6
' 5
It
xxvm.
" 1
cc
xxvm.
" 2
"
xxvm.
" 3
it
xxvm.
« 4
"
XXIX.
" 1
"
XXIX.
" 2
(C
XXIX.
" 3
"
XXIX.
" 4
«
XXIX.
" 5
u
XXIX.
" 6
"
XXIX.
" 7
It
XXIX.
" 8
CI
XXIX.
" 9
«
XXIX.
" 10
u
XXVI.
" 3
«
XXIV.
' 5
XXX.
« 1
XXX.
• 2
XXX.
< 3
XXX.
' 4
XXXI.
• 1
INDEX OF THE ILLUSTRATIONS,
19
Cells of inter-vertebral cartilage, 350 diam.
Section of cartilage and bone of rib, 130 diam.
Ditto of one of the rings of the trachea, 350 diam.
Ditto of thyroid cartilage with fibres, 130 diam.
Cartilage of ossification, 100 diam.
Section of primary cancelli, 350 diam.
Ditto of same, more advanced, 350 diam.
Cartilage of ossification, 350 diam.
Section of cartilaginous epiphysis, 30 diam.
Ditto of same, with bone, 30 diam.
Ditto of same, more highly magnified, 330 diam.
Section of cartilage and bone of rib, 130 diam.
Plate xxxi. Fig. 2
XXXI. '
' 3
XXXI.
' 4
XXXI.
« 5
XXXIV.
' 1
XXXIV.
' 2
XXXIV.
' 3
XXXIV.
' 4
XXXV.
' 1
XXXV.
' 2
XXXV.
« 3
XXXV.
' 6
BONE.
Transverse section of ulna, 60 diam.
Cross-section of Haversian canals, 220 diam.
Ditto of same more highly magnified, 670 diam.
Longitudinal section of long bone, 40 diam.
Parietal bone of fcetus, 30 diam.
Portion of same more highly magnified, 60 diam.
Spicula of bone of foetal humerus, 350 diam.
Lamina of a long bone, 500 diam.
Cancelli of long bone of fcetus, 350 diam.
Section of femur of pigeon fed on madder, 220 diam.
Section of epiphysis and shaft of foetal femur, 100 diam,
Transverse section of primary cancelli, 350 diam.
Section of cancelli more advanced, 350 diam.
Ditto of epiphysis and shaft of foetal femur, 350 diam.
Ditto of cartilaginous epiphysis of humerus, 30 diam.
Ditto of same with bone, 30 diam.
The same more highly magnified, 330 diam.
Blood-vessels and medullary cells ....
Section of shaft of foetal long bone, 20 diam.
Ditto of bone and cartilage of rib, 130 diam.
XXXII. '
• 1
XXXII. '
' 2
XXXII. '
' 3
XXXII. '
' 4
xxxiii.
' 1
XXXIII.
< 2
XXXIII.
' 3
XXXIII.
' 4
XXXIII.
' 5
XXXIII.
« 6
XXXIV.
' 1
XXXIV.
' 2
XXXIV.
« 3
XXXIV.
' 4
XXXV.
< 1
XXXV.
" 2
XXXV.
' 3
XXXV.
" 4
XXXV.
' 5
XXXV.
' 6
TEETH.
Vertical section of incisor tooth, seen with lens
Tubes of dentine near their termination, 670 diam.
A not unfrequent condition of same, 670 diam.
Tubes of dentine near their commencement, 670 diam.
Oblique section of tubes of dentine, 670 diam.
Transverse section of ditto, 670 diam. .
Transition of tubes into bone cells, 670 diam. .
Dilatation of ditto into bone cells, 670 diam.
Section of cementum, 670 diam.
Ditto of same traversed by tubes, 670 diam.
Ditto of same showing angular cells, 670 diam.
Fungus on section of dentine, 670 diam.
Oil-like globules on section of same, 350 diam.
xxxvi.
< 1
XXXVI.
< 2
XXXVI.
' 3
XXXVI.
' 4
XXXVI.
' 5
XXXVI.
' 6
XXXVI.
' 7
XXXVI.
« 8
XXXVII.
' 1
XXXVII.
' 2
XXXVII.
« 3
XXXVII.
' 4
xxxvii. ** 5
20
INDEX OF THE ILLUSTRATIONS.
Section of secondary dentine, 350 diam.
Ditto of bicuspid tooth, seen with lens only
Vertical section of enamel, 220 diain. .
Enamel cells seen lengthways, 670 diam.
Cross-section of cells of enamel, 670 diam.
Plate xxxvu. Fig. 6
" xxxvu. " 7
" xxxix. " 3
" xxxix. " 4
" xxxix. " 5
FIBROUS TISSUE.
Longitudinal section of tendon, 670 diam. " xxxix. " 1
Transverse section of same, 670 diam. ..... " xxxix. " 2
White fibrous tissue, 670 diam. " xxxix. " 6
Mixed ditto, 670 diam. " xxxix. " 7
Yellow fibrous tissue, 670 diam. ......." xl. " 1
Different form of ditto, 670 diam. " xl. " 2
Development of blood-vessels, 350 diam. . . . ; . " xl. " 3
Areolar form of mixed fibrous tissue, 330 diam. .... " xl. " 4
Blood-vessels of pia mater, 350 diam. " xl. " 5
Development of white fibrous tissue, 670 diam. .... " xliii. " 2
Portion of dartos, 670 diam. ........" xliii. " 3
Section of corpora cavernosa, slightly magnified .... " xliii. " 4
MUSCLE.
Portion of striped muscle, 60 diam. . . ,
Fragment of unstriped ditto, 670 diam.
Muscular fibrillee of the heart, 670 diam.
Fragment of striped muscle of frog, 350 diam.
Fibres and fibrillae of voluntary muscle, 350 diam.
Fibres acted on by acetic acid, 350 diam.
Ditto in different degrees of contraction, 350 diam.
Union of muscle with tendon, 130 diam.
Transverse section of muscular, fibres, 350 diam.
Fibres of voluntary muscle of fetus, 660 diam.
Zigzag disposition of fibres, 350 diam.
Striped muscular fibre and fibrillae, 670 diam.
XLI. " 1
XLI.
' 2
XLI.
« 3
XLI.
' 4
XLII.
' 1
XLII.
' 2
XLII.
< 3
XLII.
( 4
XLII.
< 5
XLIII.
• 1
XLIII.
" 5
XLIII.
' 6
NERVES.
Tubes of motor nerve, 670 diam
The same after the action of spirit, 670 diam.
The same after the action of acetic acid, 670 diam.
Portion of Casserian ganglion, 350 diam.
Nerve tubes of cerebellum, 670 diam.
Ditto of cerebrum, with clear cells, 670 diam.
Varicose condition of ditto, 670 diam.
Filaments of great sympathetic, 670 diam. .
Cells of gray matter of cerebellum, 670 diam.
Ditto of same, inner stratum, 670 diam.
Caudate ganglionary cells, 350 diam.
(Spinal cord, Medulla oblongata, Cerebellum.)
Ditto from locus niger of cms cerebelli, 350 diam.
xliv.
« 1
XLIV.
' 2
XLTV.
' 3
XLIV.
' 4
XLIV.
' 5
XLIV.
' 6
XLIV.
' 7
XLV.
' 1
XLV.
' 2
XLV.
' 3
XLV.
' 4
INDEX OF THE ILLUSTRATIONS.
21
Ditto from hippocampus major, 350 diam.
Ditto from locus niger of crus cerebri, 350 diam. .
Pacinian bodies, natural size .
Ditto, magnified 60 diam
A single Pacinian body, 100 diam.
An anomalous Pacinian body ....
Two other anomalous Pacinian bodies
Cells from corpus dentatum of cerebellum, 350 diam.
"late xlv.
Fig
G
" XLV.
"
7
" XLVI.
"
1
" XLVI.
"
2
" XLVI.
"
3
" XLVI.
"
4
" XLVI.
"
5
" XLVI.
"
6
LUNG.
Pleural surface of lung, 30 diam
Ditto, with vessels of first order, 30 diam
Ditto, magnified 100 diam
Section of lung injected with tallow, 100 diam. .
Casts of air-cells, 350 diam
Section of lung injected with size, 100 diam.
Pleural surface of lung, with vessels of second order, 100 diam.
Section of lung, with air-cells uninjected, 100 diam.
Capillaries of lung, 100 diam. . . . .
XLVII.
< 1
XLVII.
' 2
XLVII.
• 3
XLVIII.
' 1
XLVIII.
' 2
XLVIII.
' 3
XLIX.
' 1
XLIX.
' 2
XLIX.
' 3
GLANDS,
Follicles of stomach, with epithelium, 100 diam.
Ditto of large intestine, in similar condition, 100 diam
Ditto of same, without epithelium, 60 diam.
Termination of follicles of large intestine, 60 diam.
Follicles of Leiburkiihn in duodenum, 60 diam. .
Vessels of ditto of appendix vermiformis, 100 diam.
Ditto of same of stomach of cat, 100 diam.
Stomach tubes, cross-section of, 100 diam.
Longitudinal view of stomach tubes, 220 diam. .
Ditto of the same, 100 diam. ....
Villi of small intestine, with epithelium, 100 diam.
Ditto, without epithelium, showing lacteals, 100 diam.
Vessels of villi in duodenum, 60 diam.
Ditto of same in jejunum, 60 diam.
Ditto of same of foal, 60 diam. ....
Solitary glands%{ small intestine, natural size
Ditto of large intestine, slightly magnified .
Aggregated or Peyer's glands, 20 diam.
Side view of same, 20 diam. ....
Sebaceous glands in connexion with hair, 33 diam.
Ditto from caruncula lachrymalis
An entire Meibomian gland, 27 diam. .
Illustrations of Mucous glands, 45 diam.
Parotid gland of embryo of sheep, 8 diam. .
Ditto of human subject, further developed, 40 diam.
Mammary gland, portion of, slightly magnified
Ditto of same, with milk globules, 90 diam.
L.
" 1
L.
' 2
L.
' 6
L.
' 7
LII.
" 5
LI.
" 1
LI.
" 2
L.
" 3
L.
« 4
L.
< 5
LII.
' 1
LII.
« 2
LI.
' 3
LI.
« 4
LI.
< 5
LXII.
' 6
LI.
' 6
LII.
< 3
LII.
' 4
LIII.
< 3
LIII.
< 1
LIII.
< 2
LIII.
' 4
LIV.
' 1
LIV. '
< 2
LIV. '
' 5
LIV. '
« 3
22
INDEX OF THE ILLUSTRATIONS.
Ditto of same more highly magnified, 198 diam.
Liver, section of, showing the lobules, 35 diam. .
Surface of ditto, showing the intra-lobular veins, 15 diam.
Section of liver showing the hepatic venous plexus, 20 diam
Vessels of portal system, 20 diam. ....
Section of liver, showing inter-lobular vessels, 24 diam.
Surface of liver, showing portal capillary system, 20 diam.
Ditto, showing both hepatic and portal venous systems, 20 diam. ■
Ditto, with both systems completely injected, 20 diam.
Ditto, with portal vein and hepatic artery, 18 diam.
A terminal biliary duct, 378 diam. .
Secreting cells of liver in healthy state, 378 diam
Ditto, gorged with bile, 378 diam.
Ditto, containing oil globules, 378 diam.
Prostate gland, calculi of, 45 diam.
New tubular gland in axilla, 54 diam.
Tubulus of ditto, 198 diam. ....
Ceruminous glands, portions of, 45 diam. .
Sudoriferous gland, tubulus of, 198 diam.
Kidney, tubes of, with epithelium, 99 diam.
Cross-section of elastic frame-work, 99 diam. .
Ditto of frame-work and tubes, 99 diam. .
Section of vessels in tubular part of kidney, 33 diam.
The same vessels seen lengthways, 33 diam.
Tubes with epithelium, 378 diam
Corpora Malpighiana of kidney, injected, 40 diam.
Uriniferous tubes of a bird, 40 diam. . . .
Corpora Malpighiana of the horse, 40 diam.
Inter-tubular vessels of surface of kidney, 90 diam.
Transverse section of injected kidney, 67 diam.
Uninjected corpora Malpighiana
With capsule, 100 diam.
Without ditto, 100 diam. ....
Malpighian body, more highly magnified, 125 diam.
Afferent and efferent vessels of Malpighian tuft, 45 diam
Epithelial cells of the tubes, 378 diam.
Testis, tubes of, 27 diam
Tubes of ditto, more highly magnified, 99 diam.
Vessels of thyroid gland, injected, 18 diam. .
Vesicles of ditto, viewed with a lens only .
Ditto of same, magnified 40 diam.
Ditto of same, showing the structure of their walls, 67 diam.
Lobes and vesicles of same in their ordinary condition, 27 diam.
Nuclei of vesicles of thyroid, 378 diam
Follicles of thymus, with vessels, 33 diam
Capsule of ditto, 54 diam. . .
Nuclei and simple cells of same, 378 diam
Compound or parent cells of ditto, 378 diam.
Spleen, nuclei and vessels of, 378 diam
Plate
L1V.
Fig. 6
LIV.
« 4
LV.
" 1
LV.
" 2
LV.
" 3
LV.
u 4
LV.
" 5
LVI.
" 3
LVI.
" 4
LVI.
" 2
LVII.
" 1
LVII.
"2a
LVII.
"2b
LVII.
" 2c
LVII.
" 3
LVII.
"4a
LVII.
" 4b
LVII.
" 5
LVII.
" 4c
LVIII.
" 1
LVIII.
" 2
LVIII.
" 3
LVIII.
" 4
LVIII.
" 5
LVIII.
" 6
LXIX.
" 1
LIX.
" 2
LIX.
" 3
LIX.
" 4
LIX.
" 5
LX.
" 2
"
" A
tt
" B
LX.
"3a
LX.
"3b
LX.
"3c
LX.
" 1
LX.
" 4
LXI.
" 1
LXI.
« 2
LXI.
" 3
LXI.
" 4
LXI.
" 5
LXI.
" 6
lxi:
" 7
lxi:
" 8
lxi:
" 9
lxi:
" 10
lxii:
" 1
INDEX OF THE ILLUSTRATIONS.
23
Supra-renal capsule, plexus on surface of, 54 diam. .
Tubes of ditto, 90 diam
Nuclei, parent cells, and molecules of ditto, 378 diam.
Vessels of supra-renal capsule, 90 diam.
Pineal gland, compound bodies of, 130 diam.
Pituitary gland, cells and fibrous tissue of, 350 diam.
Plate lxii. Fig. 2
LXII.
» 3a
LXII.
" 36
LXII.
" 5
LXIX.
« 7
LXIX.
" 8
ANATOMY OF THE SENSE OF TOUCH,
Epidermis of palm of hand, 40 diam. "
Ditto of back of hand, 40 diam "
Papillae of palm of hand, 54 diam "
Ditto of back of hand, 54 diam. . . . . . . . "
Epidermis of palm, under surface of, 54 diam. .... "
Ditto of back of hand, under surface of, 54 diam. "
Vessels of papilla? of palm of hand, 54 diam. .... "
Ditto of same of back of hand, 54 diam. ....."
LXIII.
tt
1
LXIH.
tt
2
LXIII.
tt
3
LXIII.
"
4
LXIII.
tt
5
LXIII.
"
6
LXIII.
it
7
LXIII.
«
8
ANATOMY OF THE SENSE OF TASTE.
Filiform papillae, with long epithelial appendages, 41 diam.
Ditto, with shorter epithelial processes, 27 diam.
Ditto, without epithelium, near apex of tongue, 27 diam. .
Ditto, without epithelium, near centre of same, 31 diam.
Filiform and fungiform papilla?, without epithelium, 27 diam.
Peculiar form of compound papillae, 27 diam.
Filiform papillae in different states, 27 diam.
Ditto, with epithelium partially removed, 27 diam.
Follicles of tongue, with epithelium, 27 diam. .
Ditto, without epithelium, 27 diam. ....
Ditto, viewed as an opaque object, 27 diam.
Filiform papillae from point of tongue, 27 diam.
Follicles and papillae from side of ditto, 20 diam.
Simple papillae, with epithelium, 45 diam.
Filiform papillae, with ditto, 18 diam.
The same, viewed with a lens only ....
Side view of certain compound papillae, 20 diam. . .
Simple papilla from under surface of tongue, 54 diam. .
Compound and simple ditto from side of tongue, 23 diam.
A calyciform papilla, uninjected, 16 diam.
Ditto, with the vessels injected, 16 diam. ....
Filiform papillae near centre of tongue, injected, 27 diam.
Ditto near tip of tongue, injected, 27 diam.
Simple papillae, injected, 27 diam. ....
Fungiform ditto, injected, 27 diam. .....
LXIV.
it
1
LXIV.
"
2
LXIV.
"
3
LXIV.
"
4
LXIV.
tt
5
LXIV.
"
6
LXIV.
"
7
LXIV.
"
8
LXV.
"
1
LXV.
"
2
LXV.
"
3
LXV.
"
4
LXV.
"
5
LXV.
"
6
LXV.
"
7
LXV.
ft
8
LXV.
tt
9
LXV.
tt
10
LXV.
"
11
LXVI.
tt
1
LXVI.
"
2
LXVI.
tt
3
LXVI.
"
4
LXVI.
ft
5
LXVI.
tt
6
ANATOMY OF THE GLOBE OF THE EYE.
Vertical section of cornea, 54 diam.
A portion of retina, injected, 90 diam.
Section of sclerotic and cornea, 54 diam.
LXVII.
tt
1
LXV1I.
ft
2
LXVII.
it
3
24
INDEX OF THE ILLUSTRATIONS
Vessels of choroid, ciliary processes, and iris, 14 diam.
Nuclei of granular layer of retina, 378 diam.
Cells of the same, 378 diam
Ditto of vesicular layer of retina, 378 diam.
Caudate cells of retina, 378 diam. ....
Cells of the membrana Jacobi, 378 diam.
Fibres of the crystalline lens; a, 198 diam. ; 6, 378 diam.
A condition of the posterior elastic lamina, 78 diam.
Peculiar markings on same, 78 diam.
Crystalline lens of sheep, slightly magnified
Fibres of lens near its centre, 198 diam. .
Stellate pigment in eye of sheep, slightly magnified
Venae vorticosae of eye of sheep, injected
Conjunctival epithelium, oblique view of, 378 diam.
Ditto, front view of, 378 diam. ....
Ciliary muscle, fibres of, 198 diam.
Gelatinous nerve fibres of retina, 378 diam.
Cellated structure of vitreous body, 70 diam.
Fibres on posterior elastic lamina, 70 diam.
Portion of the iris, 70 diam.
Epithelium of crystalline lens, 198 diam. .
Ditto of the aqueous humour, 198 diam.
Hexagonal pigment of the choroid, 378 diam.
Stellate pigment of same, 378 diam. .
Irregular pigment of uvea, 378 diam.
Plate
lxvii.
Fig. 4
11
LXVII.
" 5
tt
LXVII.
" 6
a
LXVII.
" 7
tt
LXVII.
" 8
a
LXVII.
" 9
"
LXVII.
" 10
"
LXVII.
" 11
»
LXVII.
« 12
"
LXVII.
" 13
«
LXVII.
« 14
It
LXVIII.
" 1
"
LXVIII.
" 2
"
LXVIII.
" 3
"
LXVIII.
" 5
tt
LXVIII.
" 4
it
LXVIII.
" 6
it
LXVIII.
" 7
tt
LXVIII.
" 8
"
LXVIII.
" 9
it
LXVIII.
" 10
(C
LXVIII.
" 11
"
LXVIII.
" 12
It
LXVIII.
" 13
"
LXVIII.
« 14
ANATOMY OF THE NOSE
Mucous membrane of true nasal region, 80 diam.
Ditto of pituitary region, injected, 80 diam
Capillaries of olfactory region of human fetus, 100 diam.
LXIX.
" 1
LXIX.
" 2
LXIX.
" 12
ANATOMY OF THE EAR
Denticulate laminae of the osseous zone, 100 diam. .
Tympanic surface of lamina spiralis, 300 diam.
Inner view of cochlearis muscle of sheep .
Plexiform arrangement of cochlear nerves in ditto, 30 diam.
VILLI.
Villi of foetal placenta, injected, 54 diam.
Ditto of choroid plexus, 45 diam.
LXIX. '
' 3
LXIX. '
< 4
LXIX.
' 5
LXIX.
' 6
LXII. '
' 4
LXIX. '
« 9
Plates "Vm., XVII., and XXXVIII., omitted in the original edition, are likewise
here omitted. The same numbers for the other plates are observed, that the figures
in both editions may correspond.
The Plates added to the American Edition commence at Plate LXX.
PLATES ADDED
TO
THE AMERICAN EDITION
Corpuscles of lymph, 800 diam Plate lxx. Fig. 1
Corpuscles of chyle, 800 diam. . . . . . . " lxx. " 2
Fat vesicles, injected, 45 diam. ....... " lxx. " 3
Transverse sections of hair, 450 diam. ......" lxx. " 4
Cartilage from finger-joint, 80 diam. ...... " lxx. " 5
Vessels of synovial membrane, 45 diam. ......" lxx. " 6
Injected matrix of finger-nail, 10 diam. . . . . . " lxxi. "
Vessels of tendon, 60 diam. ........" lxxii. " 1
Ditto nearer muscular union, 30 diam. " lxxii. " 2
Lymphatic gland and vessels, 8 diam. ......" lxxiii. " 1
Capillaries and air-cells of foetal lung, 60 diam. .... " lxxiii. " 2
Ditto of same of child, 60 diam. ......." lxxiii. " 3
Ditto of same of adult, 60 diam. ...... " lxxiii. " 4
Branchia of an eel, 60 diam . " lxxiii. " 5
Mucous membrane of foetal stomach, 60 diam. . . . " lxxiv. " 1
Ditto, showing cells and cap. ridges of adult, 60 diam. ..." lxxiv. " 2
Ditto with cells deeper and ridges more elevated, 60 diam. . . " lxxiv. " 3
Ditto showing gastric villi, 60 diam. . " lxxiv. " 4
Villi of duodenum, 60 diam. ....... " lxxiv. " 5
Ditto of jejunum, 60 diam. ........" lxxiv. " 6
Ditto of ileum, 60 diam. ........ " lxxv. " 1
Muscular fibre of small intestine, 60 diam. ....." lxxv. " 2
Appendix vermiformis, 60 diam. ...... " lxxv. " 3
Mucous follicles of colon, 60 diam. ......" lxxv. " 4
Malpighian bodies with uriniferous tubes, of adult, 100 diam. . " lxxv. " 5
Ditto enlarged as in Bright's disease, 100 diam. " lxxv. " 6
Enlarged veins of kidney, first stage of Bright's disease, 100 diam. " lxxvi. " 1
Ditto of same, another view, 100 diam. ..... " lxxvi. " 2
Stellated veins in third stage of same, 100 diam " lxxvi. " 3
Granulation on the surface of kidn ;y, 100 diam. ... " lxxvi. " 4
A tube much dilated, 100 diam " lxxvi. " 5
Sudoriparous glands and their ducts, 70 diam " lxxvii. " 1
Ditto, more highly magnified, 220 diam. ....." lxxvii. " 2
26
INDEX OF THE ILLUSTRATIONS
Mucous membrane of gall-bladder, 50 diam.
Transverse section of muscles of the tongue, 45 diam.
Terminal vessels in cornea, 45 diam.
Cornea of viper, showing its vessels, 45 diam.
Choroid coat of foetal eye, 45 diam
Ciliary processes of eye of adult, 45 diam.
Mucous lining of unimpregnated uterus, 35 diam.
Ditto of impregnated uterus, 35 diam. .
Tuft of placenta, GO diam.
Papillae of gum, 45 diam
Ditto of lip, 45 diam.
Blood-vessels in mucous membrane of trachea, 45 diam.
Ditto of buccal membrane, 60 diam.
Ditto of mucous membrane of bladder, 60 diam. .
Plate
LXXVII. 1
<ig. 3
LXXVII.
" 4
LXXVIII.
" 1
lxxviii.
" 2
LXXVIII.
" 3
LXXVIII.
" 4
LXXVIII.
" 5
LXXVIII.
" 6
Lxxrx.
" 1
LXXIX.
" 2
LXXIX.
" 3
LXXIX.
" 4
LXXIX.
LXXIX.
" 5
INTRODUCTION.
BY THE EDITOR.
The object of the present Introduction is to furnish some practical hints
on Manipulation in Microscopic Anatomy, so that the student who is dis-
posed to pursue for himself this subject, and has not at his command other
authorities, may be provided with the information necessary to commence
his investigations.
Although plates and models are useful as companions in study, and as
giving more explicit views of authors than can be done in words, yet as
these, however excellent, can never make the student master of special
anatomy without dissection, so in the more intricate department of minute
anatomy, he who would there become a proficient, must investigate for
himself.
The same remarks apply in a manner to specimens prepared by others :
these seldom receive that close study and repeated investigation which are
willingly given to one's own attempts. The very admirable preparations
of different tissues by Hett, Topping, Darker, and others, which may now
be purchased of many opticians, should be rather regarded as standards of
success, with which the student may compare his own efforts, than as sub-
stitutes for his own manipulation.
For distinctness, it is proposed to treat the subject under three divisions :
I. Microscopes and their Accessory Instruments.
II. The Preparation of Objects.
III. The Preservation of Objects.
I. OF MICROSCOPES AND THEIR ACCESSORIES.
It will not fall within the design of this introduction, to treat either of
the theory of the microscope, or its construction. A brief description of
the various forms in present use is all that will be necessary.
Those only who have studied with the microscope, know the comfort and
satisfaction of using a good one; and by this is meant excellence not only
28 INTRODUCTION.
in object-glasses, although these are the most essential to a good microscope,
but excellence in all the details of accessory instruments, and in nice
mechanical adjustment.
It is a very common error to suppose that cheap microscopes will answer
as well for low powers as more expensive ones : that, for instance, there is
no difference in a one-inch object-glass and common eye-piece of an ordi-
nary microscope, and the same focus object-glass and eye-piece of a good
instrument : hence many persons, about commencing the study of micro-
scopic anatomy, and believing that, for the study of injected preparations, a
power of one hundred diameters will in most cases answer, purchase the
cheapest instrument they can obtain, with that degree of magnifying power,
unaware that penetration and definition are qualities that an object-glass
needs, even more than mere magnifying power — qualities that are rarely
found to exist in any degree in the cheaper microscopes.
It is in these qualities that the English and American instruments excel
the French and other continental microscopes : an observer with the former
being able actually to see more of, and see better, the construction of an
object with a glass of much lower magnifying power : the object being in
the latter case clear and well defined, while in the other, though more highly
magnified, blurred and indistinct with poor illumination. It is a great satis-
faction in viewing an object with a microscope to be able to see it as well
as any one has hitherto seen it : if not able to do this, one always feels at a
disadvantage.
An error, somewhat similar, committed by beginners, is in supposing that
a low-priced microscope (and usually therefore a poor one) is sufficiently
good to commence with, and that a more perfect instrument with higher
powers may be purchased when more familiar with its use. This is not
only poor economy, but, as already stated, such an instrument gives unsatis-
factory and often false views : it being much better economy where this is
regarded, and infinitely more satisfactory, to purchase a good instrument
with low powers at a fair price, to which the higher powers may be added
as means allow. Those who can afford a good microscope, and yet pur-
chase a poor one, commence their studies under great disadvantages.
It must not be forgotten, however, that in microscopic observation, more
depends on the observer than upon the instrument ; more upon the practised
eye, and the analytical mind, than upon the precise form of the microscope
or the number of its accessories.
The following brief enumeration of the different prominent microscope-
makers may be of service to persons at a distance about to order a micro-
scope, and who are embarrassed by the number of manufacturers, and
uncertain about the expense.
At the present time, the most elaborate and completely furnished micro-
MICROSCOPES, ETC. 29
scopes are those of English, and especially of London manufacture. A full
account of the various forms by the three principal London makers, is given
by Mr. Quekett in his " Practical Treatise on the Microscope." He, how-
ever, does not give preference to either. — Mr. A. Ross, No. 2 Featherstone
Buildings, Holborn, London, is usually considered the most prominent of
the London makers, having done more by his contributions to the literature
of the microscope, and his various improvements in its form and accessory
apparatus, than either of the other makers. His best or largest microscope
has been considered to be unsurpassed by any in the world. Its price in
London, when complete, is about $450 ; the duty on importation into this
country being 30 per cent, ad valorem. As has been mentioned in the
preface to the English edition of the present work, most of the objects
represented, are engraved as viewed with one of Mr. Ross's microscopes.
Mr. Ross makes several forms of instruments, among which the most
reasonable in price, and convenient for use, is one described in the Penny
Cyclopedia, article "Microscope."
This instrument, with object-glasses as high as ith-inch,* with the usual
accessory instruments, may be obtained in England for about $175.
Messrs. Powell and Lealand, No. 4 Seymour-place, Easton-square, Lon-
don, have of late years almost, if not quite, equalled Mr. Ross in the excel-
lence of their microscopes, and also construct several forms. One of the
steadiest and most convenient is the second size described by Mr. Quekett,
on page 77 (figure 44) of his "Practical Treatise."
The price of this instrument complete is about $350 in London, and to
those desiring a high-priced instrument the writer can safely recommend
this one, as combining great steadiness, accuracy of adjustment, and excel-
* Note. — As these fractions of an inch — ith, |th, ^th, &c. — as applied to the
focus of object-glasses, constantly recur in this introduction and elsewhere, it should
be stated that these measurements do not represent the actual distance between the
object and the object-glass in each particular case, but are used to signify what the
distance would be, if a single lens were used possessing the same magnifying power,
instead of a combination (most object-glasses being composed of three lenses instead
of a single one, and called a triplet) : in other words, a single lens, to produce the
same magnifying power as a ^th-inch triplet, would have to be a lens of |th-inch
focus. This nomenclature is unfortunate, because many are misled by it. It is,
however, in general use in England and in this country. The following table gives
the magnifying powers in diameters of Mr. Ross's object-glasses with the different
eye-pieces. The objectives of other makers do not vary much from these :
OBJECT-GLASSES.
EYE-GLASSES.
2-IN.
1-IN.
flN.
|-m.
fm.
t¥™
A. or long eye-piece, . .
. 20
60
100
220
420
600
B. or middle eye-piece, .
. 30
80
130
350
670
870
C. or short eye-piece, . ,
. 40
100
180
500
900
1400
30 INTRODUCTION.
lence in object-glasses. It is a most luxurious instrument to use. Powell
and Lealand construct another microscope, having the supports of the com-
pound body and the stage made of iron. This mounting of course consider-
ably reduces the expense, but does not diminish its value as an efficient
instrument. In this form the lever-stage is usually employed, and a micro-
scope of this description, with object-glasses as high as ith, may be imported
for about $100 ; but this sum does not include any of the expensive accesso-
ries, such as the achromatic condenser or camera lucida. Powell and Lea-
land have sent several of these instruments to this country, and they have
given great satisfaction.
Messrs. Smith and Beck, No. 6 Coleman-street (city), London, though less
prominent than either of the preceding makers, construct several excellent
microscopes; one especially, known as the "Student's Microscope," is highly
to be recommended on account of its reasonable price ; being furnished
complete with all the accessories for about $200, and combines great steadi
ness and convenience in use. The same instrument with plain stage and
object-glasses as high as ith, but without the accessories, may be had in
London for $75.
Of the French microscope-makers the most prominent have hitherto been
M. Chevalier (163 Palais Royal, Paris,) and George Oberhauser. Cheva-
lier's instrument is of the horizontal form, but capable of being converted
into the vertical or the inclined one. Though the microscope-stand and
apparatus are of good construction, the object-glasses are usually defective
in definition : such at least is the character of most of those imported in this
country. The horizontal form, recommended by Sir David Brewster as
being the best adapted for accurate observation, is to many persons fatiguing
to the eye ; and the image of the object being a reflected one, it would appear
as if some sharpness of outline must be lost by the reflection. The price of
one of Chevalier's best instruments in Paris is about $200. The accessory
apparatus is not so complete as with the English instruments.
A smaller size, similar in construction, and usually known as the "small
Chevalier," can be obtained at about half the price of the preceding instru-
ments; it is not, however, so complete in object-glasses or accessories.
The form that Mr. Oberhauser (No. 19 Place Dauphine, Paris,) adopts is
the vertical one ; a form of construction at once the cheapest and least com-
plicated. His microscopes, though often ordered from this country, and much
used on the continent of Europe, have two important faults; the first, in
common with M. Chevalier's, want of definition and penetration in the object-
glasses, and the second, inconvenience of mechanical arrangement, especially
in the means of illumination ; the mirror always being too small, and inca-
pable of affording oblique light. M. Oberhauser seems to rely more on his
short eye-pieces for increasing the magnifying power, (there sometimes
MICROSCOPES, ETC. 31
being five or six of these furnished with his microscope,) than upon his object-
glasses ; a great mistake, and always attended by loss of light and definition.
The more one studies with the microscope, the more one learns to rely on the
object-glass for power and less on the eye-piece ; objects being rarely seen
so clearly, and therefore not so well, with a very short eye-piece as with one
from two to three inches long. Views of objects afforded by M. Oberhau-
ser's combination of object-glass and short eye-piece, producing according
to his own table a magnitude of 900 diameters, are far less satisfactory, and
show less of minute structure, than the same object seen with an English ^th
object-glass and long eye-piece, producing a magnitude of not more than
220 diameters. A microscope is furnished by M. Oberhauser at about six
months' notice for $100, with a power according to his own measurement of
900 diameters.
At present, the best French microscope-makers are M. Nachet and M.
Brunner, both of Paris. The microscopes of Nachet (Rue Serpente, No. 16,)
much resembles in general form and arrangement the large-sized instru-
ments of M. Oberhauser, their excellence consisting in the superiority of
their object-glasses : they are much employed in microscopic investigations
in Paris, and are good working instruments ; the prices are about the same
as Oberhauser's, but the object-glasses are every way superior.
His largest sized instrument, complete, is sold in Paris at 650 francs. His
smallest size, at 100 francs: between these, are several intermediate sizes.
The microscope of M. Brunner (Rue des Bernardins, No. 34, Paris,) is
also a vertical one, but possesses more advantages of mechanical arrangement
than any other of the same construction ; indeed, it almost equals the more
expensive form usually adopted in England, for convenience of arrangement
and facility in use. The stage is large, and has not only a circular motion,
but also two lateral motions, made by adjusting-screws; the mirror is large,
and admirably arranged for affording oblique light. The object-glasses
supplied with this instrument are excellent, and for sharpness of definition
and light, are hardly surpassed by the best English ones. M. Brunner
also supplies the achromatic condenser, the polarizing apparatus, and other
accessories, to those who wish them ; and his prices for his best instruments
vary from $90 to $150, according to the powers of the object-glasses and
accessories furnished. The writer has no hesitation in recommending these
microscopes as the best of the vertical form, possessing, as already mentioned,
more advantages of mechanical arrangement than any other, and the object-
glasses are not excelled by any of continental make.
The rapid advances made of late years in microscopic knowledge, have
been owing, in a great measure, to improvements in the construction of
object-glasses. To this end, perhaps nobody has contributed so much as
Mr. Charles A. Spencer, of Canastota, New-York. The objectives made
32 INTRODUCTION.
by this gentleman may safely bear comparison with the best of foreign
make, and for sharpness of definition, power of penetration, and large angle
of aperture, are not excelled by any in the world. As has been already
stated, much of the excellence of an object-glass depends on its power of
penetration : this, again, depends in a great measure on the angle of aper-
ture by which the rays of light from the object enter the glass. It must be
evident that the greater the angle, the larger must be the pencil of rays.
Mr. Spencer has made some valuable experiments on this subject, and has
been enabled to obtain a curve for his object-glasses, by which in the yjth-
inch, he can give an angle of aperture of 160°. This is believed to be the
largest angle ever given to an object-glass : the greatest obtained by Mr.
Ross, was, for a Ty;h> an angle of 135°, and the one usually given to
object-glasses of the same focus by the best foreign makers, not greater than
120°. In Mr. Spencer's ith-inch object-glass, the angle of aperture is 85° ;
in the -i-th-inch, 135° ; in the objectives of foreign make, according to Mr.
Quekett, the angles are for the ^th-inch, 63s, and the |th-inch, 80°.
To Mr. Spencer is due the credit of having first resolved, with lenses of
his own construction, the fine markings on the Navicula Spencerii and
Grammatophera Subtillissima : these minute shells have since been adopted
by microscopists as test-objects for the highest powers. The Navicula
Spencerii, will exhibit one set of lines with Mr. Spencer's ith-inch object-
glass : both sets with the |th-inch. The Grammatophera Subtillissima is
a good test for a T\ih or TVth.
Of several microscopes made by Mr. Spencer, two or three only will be
here noticed. His first-class or best instrument is mounted on trunnions,
and embraces all the acknowledged improvements, in form and stage,
whereby the greatest steadiness and freedom from tremour are secured.
The price of this instrument, with all the accessories and full sets of object-
glasses, will approach $350.
The second-class instruments, complete as to object-glasses and accesso-
ries, but mounted less expensively, cost from $200 to $250.
A very efficient microscope, is one known as the "Pritchard form:" this
instrument has been somewhat modified by Mr. Spencer, and where a less
expensive instrument than either of the others is desired, this one will be
found a good working instrument, and available for all purposes of ana-
tomical study. The cost of this form, with object-glasses as high as the
ith with the usual accessories, is from $125 to $150.
Mr. Spencer also makes some simpler forms of instruments, and yet very
efficient working ones, with objectives as high as ith, the price of which
does not exceed $75.
Mr. Spencer has experienced some delay in the completion of his establish-
ment, owing to the difficulty of obtaining efficient workmen, the business
ACCESSORY INSTRUMENTS. 33
being in this country comparatively a new one, and for which it was neces-
sary to educate men and invent tools. These difficulties are now overcome,
and his establishment is in active operation.
Mr. J. B. Allen, of Springfield, Mass., has constructed several microscopes
which are said to have been very good instruments, both as to model and
object-glasses. The form is somewhat after the Pritchard model, in which
the body inclines to any angle : the object-glasses yet made have been
chiefly of low and medium powers, and have performed very satisfactorily.
Messrs. Pike and Sons, opticians, of New York, construct a microscope-
stand of great steadiness and convenience for use, the supports and general
appearance of which much resemble the large instrument of Mr. Ross.
The stage is large, being nearly four inches square, and moveable either by
adjusting-screws, and revolving after the plan described by Mr. Legg, or is
made moveable by a lever, as sometimes employed by both Powell and
Lealand, and Smith and Beck. This latter stage movement is very exact,
and allows of quick or slow motion in any direction.
The mirror is large, being about three inches in diameter, and admirably
arranged for oblique light; the quick motion is effected by rack-work, and
the slow motion by means of a conical-pointed steel screw, pressing against
the top of a slit in an inner tube, furnished with a spring : at the end of
this tube, the object-glasses are adapted.
The instrument is of considerable weight, which adds to its steadiness,
being at the same time well proportioned. Its price, with eye-pieces, all the
accessories, and without object-glasses, is about $100.
ACCESSORY INSTRUMENTS.
There are several instruments accessory to the microscope, and most use-
ful in dissection, in addition to those usually furnished with the instrument.
1. Scalpels. — The scalpels of the dissecting-case of the Medical Schools
will be necessary in making the ordinary sections, but for very minute dis-
section, much smaller-sized instruments will be found useful. The blades
of these may be either straight, curved, lancet-shaped, or probe-pointed. In
default of any instruments for this especial purpose, the small knives fur-
nished with the case for operations on the eye, may be employed.
2. Dissecting Forceps. — Small-sized forceps, both straight and curved,
are among the instruments most often required in minute dissections.
Those with exceedingly fine points, and at the same time made true, are
especially useful. The more serviceable forms are here represented :
34
INTRODUCTION,
Fig. 1.
A very convenient form of forceps, is one known as the cutting-forceps,
and is represented by figure 2 :
Fig. 2.
The sides of this instrument are riveted at the end, as those of the ordi-
nary forceps, but the cutting part consists of two scissor-shaped blades,
which overlap each other, and are prevented from crossing over too far by
a small steel pin ; the blades are bent at an angle with the sides, and by this
means the instrument can be very conveniently employed for dissecting
under a lens of half an inch focus. An instrument somewhat resembling
this, and called the microtome, is represented at figure 3 :
"It consists of two sides, like a pair of dissecting-forceps, but each terminated by
a scissor-shaped blade, arranged so that its cutting-edge is perpendicular to the broad
surface of the sides, in order to prevent the blades from opening too wide; a screw
ACCESSORY INSTRUMENTS. 35
with a fly-nut is attached to one blade, and the other moves freely upon it; the screw
is also provided with another nut, situated between the blades; the latter may be
adjusted so as to prevent the blades from being closed beyond a certain point, while the
former serves to regulate the space, that the blades may be kept open by the spring." *
This instrument is a very useful one, on account of the great precision
with which any tissue or filament may be cut, independent of any tremour
of the hand, and without deranging the preparation.
3. Dissecting Needles. — These instruments are necessary in carrying on
dissection of delicate tissues under the microscope. They may be either
curved or straight, and of different sizes. Messrs. Pike and Sons, opticians,
of New York, furnish, at a very small cost, needle-holders, in which the
needles may be changed as often as the points become broken, or otherwise
unfit for use. Straight needles may be curved by heating them in a spirit-
lamp to a red heat, and then giving them the desired curve : they should be
then again heated, and dipped in cold water to harden them.
4. Valentin's Knife. — This instrument, used in making thin sections of
soft animal tissues — like the liver, spleen, &c. — is a double-bladed knife,
the flat parts of the blades being placed against each other, and adjusted by
a screw, placed below the cutting portion of the blades. The form of this
knife is given at figure 4, and is thus described by Mr. Quekett :
JiiiiK
Fig. 4.
"This consists of two double-edged blades, one of which is prolonged by a flat
piece of steel to form a handle, and has two pieces of wood riveted to it for the pur-
pose of its being held more steadily; to this blade another one is attached by a screw;
this last is also lengthened by a shorter piece of steel, and both it and the preceding
have slits cut out in them exactly opposite to each other, up and down which a rivet,
a, with two heads, is made to slide, for the purpose either of allowing the blades to
be widely separated or brought so closely together as to touch ; one head of this
rivet is smaller than the hole in the end of the slit, and can be drawn through it, so
that the blade seen in the front of the figure may be turned away from the other, in
order to be sharpened or to allow of the section made by it being taken away from
between the blades. The blades are constructed after the plan of a double-edged
scalpel, but their opposed surfaces are either flat or very slightly concave, so that
they may fit accurately to each other, which is effected more completely by a steady
pin seen at the base of the front blade. When this instrument is required to be
used, the thickness of the section about to be made will depend upon the distance
the blades are apart; this is regulated by sliding up or down the rivet, a, as the
* Quekett's " Treatise on the Microscope."
36 INTRODUCTION.
blades, by their own elasticity, will always spring open, and keep the rivet in place;
a cut is then to be made by it, as with an ordinary knife, and the part cut will be
found between the blades, from which it may be separated, either by opening tliem
as wide as possible by the rivet, or turning them apart in the manner before
described, and floating the section out in water."
Mr. Hernstein, cutler, of New York, has made a modification of this
instrument, by making the handle curved instead of straight: this form has
the advantage of enabling the operator to hold it more firmly while making
the section ; it has the disadvantage of not allowing him to use the cutting-
edges on the concave side of the curved handle, without bringing the tissue
to be cut to the edge of the table, so that the handle has room to play below
it. Those who have not at hand one of these instruments, and cannot pro-
cure one, may make the thin section with a sharp scalpel or a thin razor.
5. Troughs. — Many delicate dissections are carried on underwater; for
this purpose, troughs are necessary on which to place the tissue to be dis-
sected. The most convenient are those made of a metal frame, about three
inches Ions:, two wide, and one inch deep, with a glass bottom, so as to trans-
mit the light when necessary. If desired, the under surface of the glass in
one of the troughs may be blackened with sealing-wax-varnish, or a piece
of black silk or common court-plaster pasted on.
In default of this form of trough, any small vessel of glass, porcelain, or
metal may be employed ; a small evaporating-dish answers extremely well.
If it is necessary to observe the object by means of transmitted light, of
course only a glass trough will answer the purpose. One larger trough,
four or six inches square, having a piece of flat cork half an inch thick,
(covered with black cloth, if desired,) and secured to the bottom by means of
the marine glue, or the compound cement, so that the tissue under dissec-
tion can be fastened with pins to the cork, will be found especially useful.
In this form of trough, dissections of entire insects, such as beetles, common
cockroaches, &c, can be carried on.
6. The Compressor. — This is an instrument by means of which pressure
may be applied at will to an object under examination with the microscope ;
various forms are in use, but the simplest and most effectual is the one repre-
sented in figure 5 :
Fig. 5.
PREPARATION OF OBJECTS. 37
" This instrument consists of a plate of brass, three or more inches long and one
and a half broad, having in its middle a circular piece of plate-glass for an object-
holder; this is slightly raised above the metal plate; at one end of the latter is a
circular piece of brass, having attached to it another piece of brass, carrying an arm
capable of being moved up and down, by means of a screw at one end, while at the
other is a semi-circle, supporting by screws a ring of metal, to the under side of
which, a piece of thin glass is cemented." *
The use of the instrument is to produce a pressure upon the object
between the plates of glass while being examined with the microscope ; the
compressor being placed upon the stage of the instrument. The object is
placed upon the under plate of glass, the arm being made to turn away for
that purpose.
7. Pipettes. — These are fine glass tubes, about eight or nine inches in
length, either straight, and of the same calibre throughout, or curved or
drawn to a fine point by means of heat from a spirit-lamp. They are useful
in applying the different reagents to the objects under examination, and also
for collecting any required portion of fluid — as urine, pus, &c. — and placing
it in the desired position for examination. They are among the most useful
of the minor accessory instruments, and can be fashioned in any shape by
the student himself.
A few only of the accessory instruments that may be used in minute
anatomy have been here described. There is much truth in the observation
of Rudolph Wagner, that the more one observes with the microscope, the
more he learns to rely on the simplest instruments; the complicated ones
giving usually more trouble than assistance. Still, there are circumstances
in which a timely use of the instruments just described will be found of
great assistance.
II.— PREPARATION OF OBJECTS.
It is designed to give but few directions for the preparation of objects for
the microscope in this place : particular directions in manipulation, for those
objects requiring an especial method of treatment, will follow the articles
in the text.
1. Fluids. — Fluids, such as blood, urine, &c, require but little prepara-
tion : a small portion of the fluid to be examined is placed on a plain glass
slide by means of a pipette, and is then covered with a small piece of thin
glass. This latter direction should be always followed, otherwise there will
be the two-fold danger of soiling the object-glass, if a high one be used, by
inadvertantly touching the fluid under examination, and also of allowing the
* Quekett's "Practical Treatise."
38 INTRODUCTION.
vapour of the fluid to condense on the object-glass, and thereby occasion an
indistinctness of vision and want of definition. Care must be taken not to
place too great a quantity of the fluid on the slide at first; one small drop is
usually sufficient. When dilution is necessary — and most of the fluids,
blood, lymph, &c, are better examined when diluted — the serum of the blood
or albumen, may be employed ; in most cases, water cannot be employed
on account of its reacting properties.
Fluids generally require higher powers for examination than solid prep-
arations. They may be first viewed with a ith-inch object-glass and then
with a |th. Any of the reagents may be introduced, without removing the
thin glass, by means of a pipette containing the reagent placed at one edge,
and a little of the fluid allowed to escape. This will be found to insinuate
itself under the glass by means of capillary attraction, and the effects should
be observed with the microscope.
2. Solids. — These usually require more care in their preparation for
examination than fluids. The hard solids, as bone, require to be cut in thin
sections, and sometimes polished before their structure can be discovered.
Particular directions for each preparation will be given at the close of the
chapters treating of their anatomy. The soft solids may be examined either
in their recent condition or be treated by various chemical agents, or be far-
ther prepared by injection. The treatment best calculated to display the
structure of each particular tissue will hereafter be given.
For making thin sections of the soft solids, the Valentin's knife or a sharp
scalpel may be used. The compressor, the small scalpels, the dissecting
needles, and the troughs for dissection will be constantly required.
Objects examined in this condition require for the most part very low
powers. If the compound microscope be used, a one or two-inch object-
glass will be power high enough. In many cases, the simple microscope
will be most efficient. In some instances, the same parts of the object require
to be examined with successive powers as high as the ith-inch object-glass.
The most difficult, as well as the most beautiful method of exhibiting the
structure of certain tissues, is by fine injection.
3. Injections. — The chief objects of minute injections are to determine the
vascularity of a tissue ; the relative order, size, and arrangement of arteries,
veins, and often-times lymphatics, and to trace the final distribution of the
larger blood-vessels in the capillaries. It will be found that different struct-
ures will present different arrangements of these vessels, always coinciding
with the differences of function.
To demonstrate these variations of structure, it is necessary that the injec-
tion should be perfect and complete. The operation is a delicate one, and
OF INJECTIONS. 39
to succeed perfectly, requires some practice ; a few attempts, however, will
convince any one how much may be attained by perseverance. Experi-
ments may first be made in comparative anatomy, and the different organs
of sheep, &c, may be always easily obtained ; and these not only afford
beautiful specimens of microscopic anatomy, but for the most part are as
difficult to inject as the same organs in the human subject, and are on
that account very good practice.
That an injection may succeed well, it is necessary, that some time should
elapse after death before the operation be attempted. It is well known that
immediately after death, a certain contractility of the vessels takes place,
which would prevent the perfect penetration of the material injected : we
must therefore wait for the relaxation of this contraction. The best time
for injecting is in summer, about twenty-four to thirty-six hours after death,
and in winter, about three days. These are general directions, which may
be changed according to the especial circumstances of the case, and the con-
dition of the organ to be injected. It would be a still greater error to wait
too long a time ; for the softened vessels would certainly be ruptured, and
extravasation of the injected material follow. This, if extensive, would not
only spoil the beauty of the preparation, but completely defeat the object of
the injection.
A serious obstacle to perfect injection is the presence of coagulated blood
and other inatters in the vessels, more especially in the veins. This point
has not been sufficiently regarded in minute anatomy, but it must be evident
that if those obstacles which irregularly contract the calibre of the vessels
could be removed, the chance of success would be much greater. A
necessary step therefore, preliminary to injection, is to wash out the blood-
vessels; this may be done by injecting tepid water or sulphuric ether, when
this latter agent enters into the composition of the injecting material. It is
also of great advantage to place the body or organ to be injected in a warm bath
for six or seven hours previous to the operation. The temperature should
be about 100° to 106° Fahrenheit. For small organs, when removed from
the body, less time will be required.
As there are several points worthy of being noted in the injection of arte-
ries and of veins, the two orders of vessels will be separately noticed.
Injection of Arteries. — As a general rule, the complete injection of the
capillary vessels, by means of the arterial trunks, is more difficult than by
the veins, for the reason that the arteries are less numerous and of less cal-
ibre than the veins. In the lungs, this disproportion does not exist; but here,
according to the experience of Rossignol, mentioned at the end of the article
on the lungs, the best injections are made by the pulmonary veins. The
arteries have the advantage of requiring less preparation than the veins, and
40 INTRODUCTION.
of being always ready; they are also more empty of coagulated blood, and
less liable to rupture, owing to the greater thickness of their walls.
Injections by the arteries should be made not by the aorta, because too
many vessels would be divided in reaching it, but by the large arteries,
which are accessible; as the carotid, brachial, crural, &c. If the injection
be made by the aorta, the visceral trunks should be first ligatured.
Injection by the Veins. — On the other hand, the veins present an obstacle
to perfect injection in their numerous valves ; it being almost impossible to
fill the vessels by one operation, owing to the repellant valvular action.
In this operation, it is sometimes necessary to inject a very liquid material
first, and after this has somewhat set, as the term is, then to inject more of
the same material, but thicker. The proportions for these divisions are
about one-third of the solid material to be injected at first, and the remaining
two-thirds in the second operation.
Another difficulty in injecting by the veins is their tendency to rupture;
this can only be prevented by using a moderate degree of force. The
existence of the coagulated blood in the veins has been already alluded to.
Inferior animals, to be injected by the veins, should be bled to death, and
the veins by which the injection is to be made, opened. The veins of the
extremities are usually injected by the superficial lateral internal and exter-
nal trunks ; when the chylo-poietic viscera are to be injected in situ, the
vessels are to be filled from the vena portse just before it enters the trans-
verse fissurb of the liver.
In either order of vessels, the opening for the canula of the syringe
should be a mere slit corresponding to the long diameter of the vessel, and
not transversely.
A young and lean subject will be found the best for perfect injection,
where this can be a matter of choice.
SYRINGE.
The first minute injections were made by Swammerdam, who taught the
art to his friend Ruysch, (born in 1638, died in 1731,) and who improved
upon Swammerdam's method.
These injections led to many discoveries, and propagated many errors.
The instrument employed by Swammerdam is still in general use in the
medical schools, and known as Swammerdam's syringe.
For making extensive injections, this instrument will answer every purpose ;
for injecting small organs and parts of the extremities, smaller instruments
must be employed. Swammerdam's syringe consists of two main parts —
the syringe proper and the canula or pipe. The canula is fastened in
the nozzle of the syringe by means of a bayonet-catch, and is of course
SYRINGES. 41
removeable at will. A modern improvement is to add a flexible tube to the
canula, so that, in the operation of forcing the injection, no injury will
happen to the vessel in which the canula is fixed, and no derangement of
the parts of the subject on the table. The canulas are of different sizes,
to correspond with the calibres of the vessels into which they are to be
inserted.
A syringe invented by Charriere, of Paris, which works with remarkable
ease and exactness, owing to the arrangement of the discs of leather which
form the piston, is advantageously used in making injections with smaller
quantities; with this syringe also are canulas of different sizes.
These syringes, with other instruments of Charriere's manufacture, use-
ful in microscopic manipulation, may be purchased at Mr. H. Balliere's
foreign book-store, No. 219 Fulton-street, New York. Many other forms
of syringe are in use, and all have their advocates ; but in general, any
form in which the working of the piston is perfectly true, and at the same
time easy, will, with proper care and attention to the exclusion of air, &c,
answer very well. The writer has made some good injections of small
organs with the ordinary ear-syringe, which is also capable of having can-
ulas of different sizes attached to it. Some of the many forms of patent
syringes sold at the druggists for making ordinary enemata, may be advan-
tageously employed, especially when the material of the injection is very
fluid, as in the method by double-decomposition, hereafter to be noticed.
These instruments would all require certain adjustments in the arrange-
ment of canulas which the student could himself make. One form of
these enema-syringes, in which the jet is continuous, and not saltatim, as in
the forcing-pump, is the best, and the syringe can be constantly supplied
with the injecting material, if necessary, by an assistant, without suspend-
ing the operation. One objection to this instrument is, that any accident
that may happen during the operation, such as rupture of a vessel, cannot
be appreciated as readily as when the piston is guided by the hand. In
ordinary injections, as already stated, the part to be injected should be
placed some hours in warm water, before the operation be attempted. The
syringe, canula, and injecting material, should be moderately heated. If
the injection is to be by the veins, and by these we are usually more suc-
cessful than by arteries, the canula, with the flexible tube, is to be
secured in the vessel previously incised longitudinally, and the canula
secured by a ligature: a second ligature should lie loose upon the canula
to secure the vessel when the operation is finished. The vein may then be
washed out by an injection of warm water; at least half an hour should
elapse, to allow the vessels to empty themselves, before the injection be pro-
ceeded with. As it is important to exclude all air in the operation, the tube
and canula should be first filled with the fluid material, the tube be tightly
42 INTRODUCTION.
corked, and the canula secured in the vessel. The next step is to fill
the syringe, and secure the tube by the bayonet-catch. The injection may
then be commenced, with a force, depending somewhat on the thickness of
the material employed ; the thinner the fluid, the less force will be neces-
sary. When it is recollected how slight is the muscular force of the heart,
it will be easy to conceive how little force will be necessary to fill the ves-
sels in favourable circumstances.
When a rupture of a large vessel occurs during the injection, and this
can be known by the greater ease with which the material enters, the ope-
ration must be suspended and the vessel secured. If the vessel itself cannot
be isolated, a ligature may be applied, including a portion of the tissue sur-
rounding it. If rupture of the capillaries takes place, the operation need
not be suspended, but pressure in the neighbourhood of the suspected rup-
ture may be applied, and the injection must be continued rather longer than
when no such accident has occurred.
The injection being finished, time must be allowed for it to set, when the
dissection may be commenced. Many patches will be found more perfectly
injected than others; and the proportionate success can only be known by
inspection with the microscope.
When the minutest capillaries are not injected, the preparation may still
be useful in displaying the second order of vessels.
Mucous membranes require to be soaked in water or washed with a
syringe, to free them from epithelium and mucus.
The minute dissection of injected tissues is best conducted in water, by
means of the trough and dissecting needles.
In conclusion, it may be observed that the operation of minute injection,
when properly performed, occupies from one to five hours, according to the
size of the specimen and the quantity of material required.
No haste should be used, for unless the material be properly prepared, and
the vessels carefully filled, one may be certain of partial or complete failure.
MATERIALS.
Many substances have been employed as the bases of fine injections, but
as the result depends more on the medium by which the solid part of the
injection is conveyed into the vessels, the most useful forms will be here
noticed in turn.
1. Injections with 'Turpentine. — In this method, materials used as paints
of various colours, are first finely ground in linseed oil, then largely diluted
with oil of turpentine. The paints most used for imparting different colours
are : Vermilion, Chrome Yellow, Prussian Blue, White-lead. In making
injections with these paints, too much importance cannot be attached to their
INJECTING MATERIALS. 43
being ground to the utmost possible fineness; otherwise the colouring parti-
cles of the injection cannot penetrate the capillaries.
These paints, already finely ground, can be procured at the stores where
"artist's materials" are sold, or they can be prepared in a "paint-mill" or
on a house-painter's slab.
The proportion of the ground paint to the oil, varies with the intensity of
of the colour; but the following scale will usually answer: For Vermilion,
•jL-th part of whole mass by weight; Prussian Blue, ^i^th; Chrome Yel-
low, Tiu th ; White-lead, yi ?th.
If it be found that the proportion of blue makes the injection too thin, the
blue may be first well mixed with the white-lead, and then a larger propor-
tion of the mixed paint employed. When too much blue is used, the colour
produced is nearly black, and therefore too strongly absorbent of light.
These injections require to be but slightly warmed, and in summer this
process may be entirely dispensed with.
When injections by this method are successful, the colours soon harden,
and are well preserved for a long time. The plan is the only one recom-
mended by M. Robin, and is much in vogue in Europe.
2. Injections with Ether.— To Dr. P. B. Goddard, of Philadelphia, is due
the merit of having first employed ether in minute injections; his method is
described by him in the Medical Examiner of Philadelphia for December,
1849, and is here quoted:
"For the purpose of making such an injection, the anatomist must provide himself
with a small and good syringe; some vermilion, very finely ground in oil; a glass-
stoppered bottle, and some sulphuric ether. The prepared vermilion paint must be
put into the ground-stoppered bottle, and about twenty or thirty times its bulk of
sulphuric ether added; the stopper must then be put in its place, and the whole well
shaken. This forms the material of the injection. Let the anatomist now procure
the organ to be injected, (say a sheep's kidney, which is very difficult to inject in any
other way, and forms an excellent criterion of success,) and fix his pipe in the artery,
leaving the rem open. Having given his material a good shake, let him pour it into
a cup, and fill the syringe. Now inject with a slow, gradual and moderate pressure.
At first, the matter will return by the vein coloured, but in a few moments this will
cease, and nothing will appear except the clear ether, which will distil freely from the
patulous vein. This must be watched, and when it ceases, the injection is complete.
The kidney is now to be placed in warm water of 120° Fahrenheit, for a quarter of
an hour, to drive off the ether, when it may be sliced and dried, or preserved in alco-
hol, Goadby's solution, or any other anti-septic fluid. For glands, as the kidney,
liver, &c, it is better to dry and mount the sections in Canada balsam : but for
membranous preparations, stomach, intestine, &c, the plan of mounting in a cell,
filled with an anti-septic solution, is preferable."
44 INTRODUCTION.
In this method, as in the preceding one, much depends on the fineness of
the colour used. The writer has examined many of Dr. Goddard's injec-
tions with ether, and can bear witness to their perfect success.
When the ether injection is employed, the preliminary steps of heating
the body and the injection must of course be dispensed with. If the veins
are to be injected, they should be washed out by an injection of pure ether.
3. Injection by Double Decomposition. — This method consists in taking
advantage of the known power of certain substances to decompose each
other, and form an insoluble compound. Upon the original method of using
these materials, Henry Goadby, Esq. (late dissector of Minute Anatomy to
the Royal College of Surgeons, London,) has made some important improve-
ments, an account of which he first published in the London Lancet, and
which has been republished in the Philadelphia Examiner for March, 1850.
Mr. Goadby thus describes the original process and his own experience:
"M. Gruby has published an account in the Comptes Rendus of some very successful
injections which he had made by employing certain fluids, which he used separately,
and which, when they met, mutually decomposed each other, and deposited the
colouring matter in the vessels themselves.
"He used saturated solutions of the chromate or bi-chromate of potash, and of the
acetate of lead: he directed that equal quantities of these fluids should be used, first
injecting all the chromate of potash, to the extent of one-half the quantity of injec-
tion supposed to be necessary, into the vessels, and subsequently the same quantity
of the acetate of lead.
"As soon as these fluids meet, they decompose each other; the acetic acid of the
acetate of lead combining with the potash to form the acetate of potash, which is set
free, and the chromic acid of the chromate of potash combining with the lead to form
the beautiful chromate of lead, which is deposited in the vessels.
" The reports which had reached me were highly confirmatory of M. Gruby's suc-
cess with these fluids, and having seen Mr. Bowman's preparations of the kidney
injected on this principle, and with the like materials, I determined to employ them.
My experiments, however, were most unsatisfactory; for, having injected a terrier
puppy, a dissection of several hours was required to ascertain whether I had succeeded
in injecting any part or not, and my best reward consisted in a patch of capillaries,
slightly painted of a pale yellow colour, and entirely wanting that roundness and full-
ness, characteristic of a good injection.
"I next procured a human foetus, and injected it, with precisely the same results.
"On making inquiry of Mr. Bowman, touching the ordinary success which had
attended his experiments, and the experiments of others, so far as he knew, he told
me that I appeared to have met with fair average results ; for that the labour of dis-
secting, consequent on using these fluids, was always great, and that the operator
must consider himself well rewarded for two or three days' work, by finding a micro-
scopic bit well injected.
"From this narration of failures, it will be evident that the fluids rarely meet in the
INJECTING MATERIALS. 45
vessels, otherwise the colour would be necessarily precipitated. With a view to see
exactly what took place, I determined to inject a piece of intestine, in which the
whole process would be under my inspection. I placed pipes in the mesenteric veins,
and secured all the cut vessels in the usual manner ; I then proceeded to throw in
the chromate of potash, and found that the potash would not wait for the lead, but
came out instantly through the parietes of the vessels as fast as it went in, and in
one broad stream covered the table. I repeated this experiment a number of times,
but with the same uniform result; on some occasions I threw in the lead also, and
as the vessels were moist with the chromate, the slight painting I have mentioned
took place; but as only equal quantities of the two fluids produce the best colour,
the excess of the lead was useless.
"Having observed, at this stage of my experiments, that the precipitated chromate
of lead is remarkably fine and soft, I determined to use it, in lieu of vermilion, with
size; and although the success was far greater than when I used the fluids separately,
the results were in no way superior to the old red injection.
"The principle involved in M. Gruby's use of these fluids — that, namely, of forming
the colour within the vessels themselves — appeared to be undeniably good, notwith-
standing it had so signally failed in my hands, and, as far as I could learn, in the
hands of all those persons who had hitherto employed it ; and I had no doubt that if
I could succeed in giving some consistence to the fluids, the results might prove more
satisfactory. For this purpose, size would not do, as it is rarely, when bought,
much too strong for use, and it would not bear further dilution. I therefore pro-
cured the highly concentrated preparation employed by pastry cooks, and sold by
by grocers, under the name of gelatine. The following is my formula for the double
injection with this material:
"Sat. solution of bi-chromate of potash, eight fluid ounces; water, eight ounces;
gelatine, two ounces.
"Sat. solution of acetate of lead, eight fluid ounces; water, eight ounces ; gelatine,
two ounces.
"Thus, gelatine, two ounces, are dissolved in sixteen ounces of fluid, and kept and
used separately as before; but the success consequent on the addition of the gelatine
was quite extraordinary; the vessels were all full and round, and there was no
extravasation; and for reasons hereafter to be explained, the microscope revealed
scenes so rich in depth, colour, and beauty, as to exceed the- best red injections I
have ever seen.
"With this form of injection I have never failed; I have injected three foetal sub-
jects so minutely, that the capillaries of the skin, and of every tissue, were perfectly
injected. Among the best specimens I obtained, I may mention injections of the
papilla? of the lips, gums, and tongue; of the pulps and capsules of the teeth; of the
conjunctiva and other tissues of the eye; of the mucous membrane of the nose and
cellular tissue; fascia; periosteum, &c; ceruminous glands, lymphatic glands, and
thyroid glands; pericardium, auricles of the heart, vasa vasorum, particularly of the
aorta and vena cava, and the vessels of all the nerve sheaths. In line, one foetus
occupied me in dissecting, ten hours a day, for two months, and was scarcely half
finished at the expiration of the time.
"Having described the success attending the use of these injecting fluids, I must
46 INTRODUCTION.
new say how they are to be mixed and used, as every thing depends on care in these
respects.
"Each parcel of gelatine must be dissolved in the water only, (eight ounces,) and
in a separate water-bath. The water-baths I employ consist of two earthern pans,
such as are applied to a child's chair, and capable of containing about one quart each;
these are fitted to two tin kettles, the broad flange of the earthern pan resting on the
rim of the kettle, the pan covered with a common saucepan-lid. The kettles should
be furnished with a bail of iron wire, like that of a glue-pot, or pitch-kettle.
"The gelatine is to be slowly dissolved in the eight ounces of water; when this is
accomplished, the eight fluid ounces of bi-chromate are to be added to the gelatine
in one pan, and the eight fluid ounces of acetate of lead to the gelatine in the other ;
each should be we'l mixed by stirring with a glass rod, a separate rod being used
for each solution, lest the chromate of lead should be precipitated.
"The fluids thus prepared, must then be strained through fine flannel (using a
piece for each fluid) into other vessels, the earthen pans cleaned, and the fluids
returned to them. The injections are now ready for use, and must be kept at a tem-
perature of about 90° by the warm water contained in the kettles.
"Directions for using the Injection. — The best subject to inject is a foetus, as there
are no cut vessels by which the injection can escape. A pipe, with a stop-cock
attached, should be firmly tied in the umbilical vein, leaving the arteries open until
the yellow injection makes its appearance, when they should be secured. It is most
essential that, for this injection, the subject be warmed through by immersion in
warm water, the temperature of which must not be higher than 90°, or corrugation
of the tissues will take place ; it will require from one hour to two hours to accom-
plish this, and the temperature must be maintained until the injection be completed.
The whole sixteen ounces of the potash preparation of gelatine must now be used,
care being taken that its temperature never exceed 90°. Some manipulators deem
care of little import in the early stage of injecting, and throw in the first few syringe-
fulls rapidly, and only exhibit caution when the subject begins to fill. In my expe-
rience, this is an error; and he who would succeed, must be equally careful and
patient throughout. It is my practice to let the piston descend so slowly, that it can
scarcely be seen to move.
" Having used the whole of the first preparation, the acetate of lead must be used,
when the colour will instantly be formed, and give the operator some idea of his
progress.
"The temperature of the subject must be kept up, and a fresh batch of injection
made and strained as before. In about half an hour the injection may be resumed,
and the bi-chromate again claims precedence; but only half the quantity need be used
now, followed by an equal quantity of the lead. At this point the stop-cock should
be turned, and the subject again allowed to rest for half an hour; the remainder of the
injections may then be used, and after this, in all probability, the subject will require
another batch. The manipulator who employs, for the first time, as much injection
for a foetus as I have already directed to be used, and who experiences the great
resistance opposed to the transmission of the last several syringes-full, especially as
the body will by this time be swollen and tense to an amazing degree, will feel
somewhat surprised to learn, that if he suspend the operation for an hour, keeping
up the temperature in the meanwhile, he will be able to throw into the subject twenty
INJECTING MATERIALS. 47
or thirty ounces more with comparative ease, and have the pleasure of seeing many
isolated congeries of vessels of the skin gradually approaching each other, and finally
anastomosing most perfectly, while the tension of the body will be so great, that if
the piston be pressed completely down, and the hand withdrawn, it will gradually rise,
and the same may, with care, be repeated several times, without causing extravasation.
"Towards the conclusion of the process, the injections should be thrown in alter-
nately ; and this should be continued, notwithstanding the prodigious distortion of the
body, as long as the injection is felt to flow in the vessels. To inject a foetus well,
on this plan, will occupy from four to five hours. The operation finished, the body
should be thrown into cold water, and should not be dissected until the next day.
" The Dissection, — Will soon reveal what has become of the injection, and is alto-
gether a disagreeable and difficult task. It will be found that nearly all the gelatine
and acetate of potash have transuded and separated the tissues widely from each
other, and that the blood has been diluted, and intimately mixed with the gelatine,
which is coloured by it.
"The majority of preparations thus injected, require to be dried, and mounted in
Canada balsam. Each preparation, when placed on a slip of glass, will necessarily
possess more or less of the coloured infiltrated gelatine, which, when dry, forms,
together with the different shades of the chromate of lead, beautiful objects, possessing
depth and richness of colour. The gelatine also separates and defines the different
layers of vessels. By this injection, the arteries are always readily distinguishable, by
the purity and brightness of the chromate of lead within them, while the veins are
detected by the altered colour imparted by the blood.
"Those preparations which require to be kept wet, can be preserved perfectly in
my B-fluid, specific gravity 1,100; the A-fluid destroys them.
"The bi-chromate of potash is greatly superior in colour to the chromate, which
yields too pale a yellow; and subsequent experience has convinced me that the ace-
tate of potash frequently effects its liberation by destruction of the capillaries, and
this, even long after the preparations have been mounted in Canada balsam ; perhaps
this may be owing to some chemical action of the acetate of potash upon them.
"Although highly desirable, as the demonstrator of the capillaries of 'normal tissues,
I do not think this kind of injection fitted for morbid preparations, the infiltrated
gelatine producing appearances of a puzzling kind, and calculated to mislead the
pathologist.
"In preparing portions of dried, well-injected skin for examination by the micro-
scope, I have tried the effect of dilute nitric acid, as a corroder, with very good results.
But probably, liquor potassse would have answered this purpose better."
The writer has inspected many beautiful injections in the possession of
Dr. Goadby, by his chemico-gelatinous method, and can confirm the fore-
going account of his success and the excellence of his method.
Dr. Goadby, in the article referred to, recommended that the nitrate of
lead be substituted for the acetate ; on experiment, however, this change has
not been found to answer, as the colour after mounting has been observed
to fade.
Other colours may also be obtained by the method of double decompo-
48 INTRODUCTION.
sition ; thus, a red precipitate, by the iodide of potassium and the bi-chloride
of mercury ; blue, by the ferro-cyanide of potassium and the peroxide of
iron, &c.
Most of the preceding remarks apply — 1st, to cases in which the whole or
large part of the subject is to be injected ; and, 2d, to cases in which both
arteries and veins are to be injected by one material.
The perfect injection of only one set of vessels or the two sets by differ-
ent materials, so as to fill the capillaries, and yet not exceed each one's
proper limits, is one of the most difficult operations in minute anatomy : it
is comparatively easy to fill both orders of vessels by one injection.
With regard to the amount of force, and quantity of fluid necessary for
the injection of only one set of vessels, no directions can be given that
would not require modification according to each particular case ; and suc-
cess must depend more on repeated trials than upon any rules.
In cases where two or more materials are to be injected, the arteries, on
account of their lesser volume, should be first filled. The colours may be
used in the following order: Arteries, blue; Veins, yellow.
When red and yellow are used, the two colours meeting in the capillaries,
form an orange tint, making it difficult to recognise each proper colour.
When the liver is to be injected, its four orders of vessels may be thus
filled : Arteries, blue ; Vena Portse, yellow ; Hepatic vein, red ; Hepatic
duct, white.
When the uriniferous tubes are to be filled, they may be injected with white.
A few other materials for fine injections may be here noticed, although
the best have been already given :
Pure Gelatine. — In using this material, Tulk and Henfrey direct that
seven parts in winter and twelve parts in summer of dried gelatine be dis-
solved to the consistence of jelly in one hundred' parts of water. The jelly
is then to be made liquid, as flowing as water, by gentle heat, and the
colouring matter added. The colouring particles must be suspended in
water : a red colour may be produced by vermilion or carmine ; blue, by
indigo or Prussian blue ; yellow, by gamboge, &c.
After the injection has been strained through a fine cloth, it is ready for
use, and must be thrown in while warm. This gelatine is the same
employed by Dr. Goad by in his method by double decomposition, and ma)r
be procured at the druggist's or grocery stores.
Fresh milk, used before the cream has commenced to form, and coloured
by a watery suspension of the finest particles of indigo, carmine, &c, may
also be used. When the injection is completed, the preparation must be
deposited in acetic acid, or dilute hydro-chloric acid, for twelve hours to
coagulate the milk.
PRESERVATION OF OBJECTS. 49
This form of injection is said to be well adapted for organs that have been
preserved for any time in weak alcohol. In this fluid, the vessels become
so contracted, that any thing like minute injection is very uncertain.
The ingredients employed by Berres and Hyrtl, of Vienna, whose
injections have become so famous, are finely levigated cinnabar, copal var-
nish, and gum mastich. For a full account of Berres' method, see his
" Microscopic Anatomy," fob, published at Vienna, in Dutch and Latin, 1837.
In conclusion, the writer would state that, from personal experience and
observation, any of the foregoing methods may prove perfectly efficient and
satisfactory, if proper time be allowed to make the injection, due attention
paid to the preliminaries, and sufficient perseverance exercised to obtain
any useful experience.
The anatomist will therefore find it to his interest to persevere in any
particular form of injection he may select, rather than make occasional
trials with different materials.
In addition to these requisites, success, in any given case, will be found
to depend much on the peculiar condition of the vessels, a certain willing-
ness on their part (if it may be so expressed) to be injected. This condition
will be more generally found in animals that have been bled to death.
III.— PRESERVATION OF OBJECTS.
To properly preserve objects that have cost much time and labour to pre-
pare, will be at once acknowledged a most important part of microscopical
manipulation. The different cements useful to the microscopist will be
first described. Not to embarrass the beginner with too long a list, the
most useful only are given.
CEMENTS.
1. Jaf annex's Gold-size. — This mixture may be obtained at almost all the
varnish stores, and consists of boiled linseed oil, dry red-lead, litharge, cop-
peras, gum-animi, and turpentine. Its cost is trifling, but it needs to be
about three years old before it will dry rapidly. It should have the consist-
ence of thick syrup, so as not to run too much when applied. If the gold-
size be too thin, it may be thickened by being rubbed up with a little lamp-
black or litharge. This cement is the most useful of all for fastening the
covers of cells, and may also be employed for cementing the cells them-
selves to the glass slides.
2. Asphaltum Cement. — This is made by dissolving asphaltum in boiling
linseed oil or turpentine, and is of fine jet-black colour. It may be used for
cementing cells to slides, or cementing down the covers of the cells. It is
4
50 INTRODUCTION.
not acted on by weak alcoholic solutions, and may therefore be used when
alcohol is employed as the mounting fluid : as a cement for the covers of
cells, it is by no means equal to the gold -size.
3. Sealing-wax Cement. — This is prepared by dissolving a quantity of
any coloured sealing-wax in alcohol, sufficient to produce a cement of the
consistence of thick syrup. Its uses are the same as the two preceding
cements, but inferior to both.
4. Canada Balsam, dissolved in ether or turpentine, and evaporated to a
consistence sufficient to allow its being laid on with a camel's-hair brush,
has been recommended as a cement for fastening cells to the glass slides.
Tt needs, however, the addition of a little heat, to render it sufficiently fluid
to make the union firm, and free from air bubbles. This heat may be
applied by means, of a spirit-lamp to the under side of the glass slide, after
the balsam has been put on, and the cell placed in the desired position.
When the balsam becomes fluid, the cell may be pressed down, and the air
bubbles will escape. This cement is apt to become brittle by age.
5. Marine Glue. — This substance is in most use abroad for cementing
cells to glass slides, and is composed of gum-shellac, caoutchouc, and naptha.
The kind best adapted for microscopic purposes, is that known in commerce,
as G. K. 4, and may be procured from Messrs. Pike and Sons, opticians,
of New York, at a small expense.
The directions given by Mr. Quekett, and others, for its use, involve a
long and tedious process, and are here omitted. A method equally good,
and consuming much less time, has been adopted by the writer, and is in
every way satisfactory : A small tin cup, with a cover, is used, capable of
holding about six ounces ; into this is poured about two ounces of Canada
balsam, and about the same quantity in bulk of the marine glue, cut in
shavings. These are placed over a spirit-lamp, or in a sand bath, and stir-
red occasionally, until they begin to boil, when the cement is ready for use.
It is then applied with a brush to the under side of the cell to be cemented
on, and pressed on the glass slide, previously warmed. By this method,
twenty-five or thirty cells may be cemented in a very few minutes, and the
cement may be put aside, and will be again ready for use on being heated
to fluidity.
6. Compound Cement. — This mixture, which the writer has found the
most useful and least troublesome of all cements, is made — first, of gum-shel-
lac dissolved in naptha, and of the consistence of syrup; this cement — as
it dries very quickly and is quite hard and firm — would be very useful by
PRESERVATION OF OBJECTS. 51
itself, were it not for its brittleness; this is obviated by mixing it with equal
parts of thick gold-size. This cement, which must be kept in a stoppered
bottle, is always ready for use, and may be applied without heat, by means
of a camel's-hair pencil, to the under side of the glass cell. This is pressed
firmly on the glass slide, and the superfluous cement may be scraped off,
when hardened. This cement dries rapidly, is not brittle, is not acted on
by any of the fluids commonly used for mounting objects, and has the great
advantage of being always ready. It may also be used for fastening the
covers of cells where a thick cement is needed. But for this purpose noth-
ing can be better than the gold-size, three or four years old.
7. Gum- Arabic Cement. — A very strong cement may be made by dis-
solving three parts gum-arabic and one part of fine sugar in distilled
vinegar.
The cement sold in the shops as the diamond cement, which depends for
its adhesiveness on the isinglass contained in it, and also the liquid glue,
which contains a large portion of gum-shellac, may be made use of as
occasion requires. The best cements, however, are the first, fifth, and sixth
of those already mentioned.
Glass Slides and Cells for preserving Objects. — The glass slide, so useful
in microscopic examinations, and so necessary in the preservation of objects,
is a plain slip of thin plate or flattened crown-glass, three inches long and
one inch wide. The size is of course arbitrary, but the one mentioned is
that recommended by the London Microscopic Society, and is in general
use by English and American microscopists : it is therefore desirable that in
exchanges and purchases, a uniformity of size should exist. The plate or
crown-glass is purchased in sheets; the former being much the best, but
most expensive, and is first cut with a glazier's diamond in slips three
inches wide; these are again cut in slips one inch in width, which gives
the necessary size: the rough edges are made smooth by rubbing them on
a cast-iron plate, with emery-powder wet with water. It is much better,
however, to have this done at a lapidary's or glass-cutter's; Mr. Isaac Tay-
lor, glass-cutter, corner of Hester and Elizabeth streets, New York, will
smooth any number of slides at the rate of fifty cents per one hundred.
Thin Glass. — The thin glass used for covering certain objects, fluids, &c,
while under examination with the microscope, and for forming the covers of
cells that are destined to preserve objects, is manufactured by Messrs.
Chance and Company, of Birmingham, solely for this purpose. It is of two
varieties of thickness, and known as thick and thin glass : in each case it is
sold by the ounce, the thin glass costing about twice as much as the other,
52
INTRODUCTION
but of course containing more in surface. Messrs. Chance and Company
have a branch of their house in New York, at No. 42 Cliff-street, and are so
obliging as to sell any quantity, however small, at much more moderate
rates than were formerly demanded by opticians and others, who imported
it themselves. The plate and crown-glass for slides may also be procured
at the same house.
For use, the thin glass is cut in squares, about three-quarters of an inch
in size, or in circles, a little less in size than the outer circumference of the
cell to be covered. In either case, the cutting is performed by a writing
diamond, the glazier's diamond being too heavy. To cut the thin glass in
squares is very easy, care being taken that the sheet of glass to be cut is
made to lie flat on a hard smooth table, or, still better, on a sheet of plate
glass slightly wet. To cut circular covers from thin glass, is rather more
difficult : it may be done by taking a thin section of glass tube, or a circular
piece of stout gutta-percha, of the size desired for the covers, and laying
it on the thin glass (this having been previously cut in strips), and then pass-
ing the diamond either inside or outside of the circle, according to the size
desired.
For those who prefer this method of cutting circular covers, a most useful
instrument has been devised by Mr. Wm. E. Johnson, of Utica, consisting
of a stout piece of German silver or other hard metal, about eight inches
long, one and a half wide, and one-eighth of an inch thick. In this plate
are drilled circles of different sizes, from T9g to |f of an inch in diameter.
The circular covers of thin glass can, by aid of this instrument, be cut of
any required size, and the weight of the metal makes the instrument less
liable to slip, than when a section of tube or gutta-percha is used. The
form of the instrument is represented at Fig. 6 :
To cut glass satisfactorily by this method, it is necessary to use a dia-
mond having a true point, or one that will cut in any direction. Most of
the writing diamonds sold, will cut but in one direction.
Mr. Quekett has described an instrument devised for the purpose of cut-
ting thin circular covers. A much simpler instrument, however, is repre-
sented in Fig. 7 :
PRESERVATION OF OBJECTS.
53
Fig. 7.
It usually forms one of the instruments furnished in a mathematical instru-
ment case, and can be readily procured at any store where such instruments
are sold : It consists of two arms united by a cradle joint ; one arm pointed,
like the arm of a pair of ordinary dividers. The other arm is about one-
half the length, having a circular opening, divided perpendicularly in the
centre. The two sides of this circle are made to approach and separate by
means of a small adjusting-screw. The original design of the instrument,
is to draw circles on paper, by means of a lead pencil fastened in the circu-
lar opening by the screw. In cutting glass, the writing diamond is substi-
tuted for the lead pencil, and after the cutting-point of the diamond is turned
in the proper direction, the diamond-holder is to be secured at the proper
distance by means of the screw: as the steel arm of the instrument usually
terminates in a sharp point, this must be removed, and a blunt point made.
This may rest on a small circle of flat lead or box-wood, or gutta-percha.
If it be found this rest is disposed to slip, a piece of chamois leather may
be pasted on the under side of the rest ; if necessary, this may be moist-
ened with a little water or a thin mucilage of gum-arabic.
The instrument having been adjusted so as to cut a circle of the required
size, is firmly held upon the thin glass, this having previously been cut in
slips a little larger than the required circles, and made to describe a circle
54 INTRODUCTION.
in the same manner as if the lead pencil and paper were used. Sometimes
it will be found better to turn the slip of glass round, holding the diamond
stationary. The pressure must be light, but steady, and the edges outside
the circle are easily removed. ,
Glass Cells. — For the preservation of injected preparations and other
thick animal structures, some kind of cell is necessary in which to deposit
the object. This cell may be made of glass, of gutta-percha, or some thick
cement, painted on the slide in the desired shape, and allowed to harden.
Those of glass are the best, and are of different kinds.
1. The Thin-glass Cell. — This cell, useful in mounting thin and delicate
structures, is made by taking a square inch of the thicker kind of thin glass,
and drilling a hole in it of about half an inch in diameter. The glass so
drilled is then to be cemented to a plain glass slide, by means of the marine
glue, or the compound cement, in the manner already described. When the
cement becomes dry and hard, the cell, after being properly cleaned, which
may be done by scraping off the harder portions of the cement with a knife,
and then washing the cell with a solution of borax, or some sulphuric ether, is
ready for use.
2. The Drilled Cell, is made in the same way, but in this form, plate-glass
of any desired thickness may be employed, according to the thickness of the
object to be mounted. Hence, if this form of cell be used, it will be neces-
sary to have them of different degrees of thickness, as well as of different
sized calibres. They are to be cemented to the glass slides in the same
manner as thin glass cells. When these cells are well made, they are the
best in use; but, as will readily be seen, it is a difficult matter to drill the
holes without fracturing the glass.
3. Tube Cells. — These are sections of stout glass tube, of different cali-
bres, from ith to |ths of an inch, cut of any desired thickness, and cemented
to the glass slide in the same manner. These sections are readily made by
means of a lapidary's wheel, charged with diamond-dust; afterwards the
cut surfaces must be ground perfectly flat, but not polished. These cells
are exceedingly neat in appearance, and can be obtained at much less cost
than the drilled cells. Mr. Mason, lapidary, No. 156 Fulton-street, has
made many of these cells for different microscopists in this city, and at much
less price than it would cost to import them. Where only one size can be
obtained, a cell of about f ths of an inch in calibre, and ith of an inch in thick-
ness and height when cemented, will be more generally useful than any
PRESERVATION OF OBJECTS. 55
other one size. It is better to have them of different sizes, where this is
possible.
4. Built-up Cells. — When neither of the preceding forms of cells can be
obtained, the built-up cells will be found a good substitute, and can be easily
made by the student himself. These consist of four pieces of glass of proper
thickness and width, cemented to a glass slide, so as to form an oblong or
square cell. Take, for instance, a piece of plate-glass, |th of an inch in thick-
ness, one inch in length, and f ths of an inch in breadth ; then with a glazier's
diamond and rule, cut off strips from each side, ith of an inch in width, and
cement these to the plain glass slide, in the precise order in which they
were cut off. This latter step in the process may be insured by marking
the different corners with ink or the point of a diamond. These cells may
be made of any size and thickness, and in these, as well as in the other
forms of cells, the marine glue or the compound cement may be used.
5. Gutfa-Percha Cells. — Another very serviceable kind of cell, which
may be employed when the drilled or tube cells cannot be obtained, is made
from gutta-percha. Dr. Goddard, of Philadelphia, was the first to adopt this
form, which is readily made in the following manner : Take a flat piece of
gutta-percha of about |th of an inch in thickness, and with a saddler's-punch,
f ths of an inch in diameter, cut several circles from the gutta-percha : then
with a punch one size smaller, or about fths of an inch in diameter, cut from
these circles a centre piece. This is to be thrown aside, and there remains a
cell, resembling a glass tube cell, ith of an inch in depth, and with the sides
-i-th of an inch thick : this is then cemented with the marine glue and Canada
balsam to the plain glass slide, in the same manner as the other forms.
Other cells may be made of white lead, melted marine glue, or gold-size
thickened with lamp-black. These substances are all to be traced on the
glass slide when in a fluid state, so as to form the necessary sized cells, and
allowed to harden before fit for use. The superfluous material may be cut
away before mounting the object.
Gutta-percha dissolved in chloroform, on account of its quickly-drying
properties, has been recommended for this variety of cell. The writer has
used it, but does not find it possesses any advantages over the other substances
already named, and indeed is not equal to the cell made with gold-size and
lamp-black.
In constructing cells of either of these materials, it has always been found
difficult to draw the cell so true in form, as to have a neat appearance. The
writer has adopted a method by which circular cells may always be
described exactly true, and made of any desired depth. For this purpose,
56 INTRODUCTION.
the little instrument with the writing diamond used in cutting circles of thin
glass, is employed.
In the present operation, a camel's-hair pencil, fine or coarse, according
to the desired thickness of the cell, is substituted for the writing diamond :
the pencil, having been dipped either in the asphaltum, gold-size, or any-
other cement, is made to describe a circle in the same manner as the dia-
mond in cutting the thin glass. Smaller cells, constructed in this way, will
be found very useful in mounting minute portions of muscular fibre and
other delicate structures that require to be viewed with high powers.
FLUIDS FOE MOUNTING OBJECTS,
These require to be varied according to the nature of the structure to be
mounted : among many that may be used for this purpose, the following are
the most useful :
It may be here remarked that all the fluids that may be employed in
mounting objects, should be prepared sometime before required for use;
otherwise many of them will be found to contain an infinite number of air-
bubbles, which will require the object to be remounted before it can be
studied with the microscope.
1. Alcohol and Water. — As in the preservation of large specimens of
general anatomy, alcohol and water is more generally useful than any
other fluid, so by the microscopist, this mixture is more to be relied on than
any other. The proportions used in ordinary preparations (equal parts of
water and alcohol) will be found too strong for most of the cements used in
microscopic manipulation ; and it has been ascertained that a weaker solu-
tion than the above will answer perfectly well as a preservative, and not act
on the cement. The proportion best adapted for this purpose, is one part
alcohol, about 60° above proof, to five of distilled water : with this fluid,
the gold-size, or asphaltum, may be safely used in cementing down the
covers of cells.
2. Goadoy's Solution. — The following formulse are those in use by Dr.
Goadby, for the second of which he was rewarded by the " Society of Arts,"
with a gold medal.
A-l Solution. — Rock salt, 4 ounces; alum, 2 ounces; corrosive subli-
mate, 2 grains ; water, 1 quart. Mix. Very astringent.
A-2 Solution. — Rock salt, 4 ounces; alum, 2 ounces; corrosive subli-
mate, 4 grains ; water, 2 quarts. Mix. Generally useful, except where
the carbonate of lime is present.
B Solution. — Rock salt, 8 ounces ; corrosive sublimate, 2 grains ; water,
FLUIDS FOR MOUNTING OBJECTS. 57
1 quart. Mix. Specific gravity, 1.100. — Two ounces of salt in addition
to each quart of water will make the specific gravity 1.148.
This solution preserves the transparency of all tissues, and is used for
terrestrial and fresh-water animals. Marine animals require the specific
gravity to be increased to 1.148 or even higher.
3. Acetate of Alumina. — The famous Gannal process, formerly so much
in vogue in Europe, consists in using one part of acetate of alumina, with
four of distilled water, either as an injection, when it is said it will prevent
decomposition, or as a fluid for mounting objects. Its destruction of bone is
an objection to its employment under certain circumstances.
4. Creosote. — This is an excellent preservative, but requires some care
in its preparation with water. One of the best methods is to mix it with
water, and then distil the mixture. The water will come highly charged
with the creosote. The only objection to the employment of this fluid, is its
tendency to turn the preparation brown. An excellent fluid, known as Mr.
Thwaite's fluid, contains creosote as an ingredient, and is thus prepared :
To sixteen parts of distilled water add one part of pure alcohol and a few
drops of creosote : stir in a small quantity of prepared chalk, and then filter:
with this fluid mix an equal quantity of camphor-water, and strain through
a piece of fine linen.
5. Glycerine. — This fluid, now to be obtained at most o the drug-stores,
forms with equal parts of water a valuable preservative for delicate tissues,
in which it is important to preserve the bright colours. Hence, for the deli-
cate colours of living infusoria, it will answer better than any other fluid.
If the glycerine be used pure, its highly refracting properties will sometimes
prevent the object from being well shown. To the glycerine, salt, corro-
sive sublimate, spirit of wine, or creosote, may be added, if desirable.
6. Canada Balsam. — This very useful material is employed when it is
desired to increase the transparency of an object, as in sections of teeth, bone,
&c, or in some instances, to mount injectings that have become dried. It
may be used with heat or without, and directions will be subsequently given
for its use in both methods.
7. Salt and Water. — A solution, containing five grains of common salt
to one ounce of distilled water, will preserve many animal and vegetable
preparations. Mr. Quekett mentions that the common objection to all saline
preservatives, viz: the growth of conferval in them, may be obviated by
58 INTRODUCTION.
the addition of a few drops of creosote or camphor mixture. This, however,
is inferior to Goadby's B-solution.
8. Naptha. — In the proportion of one part of naptha to seven or eight of
water, a good preservative is obtained for ordinary objects. It is stated that
this mixture is now generally used abroad by Messrs. Hett, Topping, and
others, as the best preservative of injected preparations. If this be true,
it is a strong recommendation in favour of its employment.
Dr. Hannover, in Muller's "Archives," 1840, recommends the employ-
ment of a solution of chromic acid as a preservative fluid, and also, as a
fluid in which soft tissues may be hardened for future dissection. In a weak
state, as one part to twenty of water, pus, mucus, epithelium, blood corpuscles,
and other delicate structures, are well preserved : when the solution is too
strong, the tissues acquire a yellow or even red colour.
The writer has not used this solution as a preservative sufficiently long
to test its merits, but can speak well of its hardening properties : brain, liver,
and other soft tissues, after being deposited in this solution a short time,
acquire a degree of hardness sufficient to allow of very thin sections.
The following excellent general directions for mounting objects, are given
by Mr. Quekett, in his work already so often quoted : " For all large speci-
mens, such as injections, the spirit and water, or Goadby's first solution, may
be used; and for others, either the creosote or glycerine solutions, as those
containing saline matter, when placed either between glasses simply, or in
the thin glass cells, are apt to crystallize slowly, and interfere with the objects
that are mounted in them. Goadby's solution, containing both salt, alum,
and corrosive sublimate, will keep animal structures that have been injected
with size and vermilion, exceedingly well ; but those in which the vessels
are filled with flake-white will have that substance destroyed in a few hours;
in these cases, either the arsenical or the spirit and water only should be
employed. The glycerine fluid, when kept for some time, is apt to become
mouldy, it should, therefore, be mixed in small quantities, and then only a
few hours before it is required. When objects are to be mounted in either
of the above fluids, it must be laid down as a rule, that they should have
been soaking for some hours in the same fluid, or in a fluid of a similar
kind ; this should be more particularly attended to, when the preparation has
to undergo dissection in water, previous to its being mounted. It has often
happened to the author to find a preparation that had been dissected in water,
and mounted in a cell in spirit and water immediately after, completely
covered over with small air-bubbles in a few hours, from the slow admixture
of the two fluids. With Goadby's solution, it does not so often happen ; but
with this, a white sediment will be sometimes deposited in the bottom of the
FLUIDS FOR MOUNTING OBJECTS. 59
cell when the preparation has been soaking in spirit for some time
previously."
Objects are usually mounted in one of four ways. These are — 1, the
dry way; 2, in Canada balsam with heat; 3, in fluid; 4, as opaque objects.
l.-THE DRY WAY.
This method is adopted in mounting objects which show best their
peculiar structure without the addition of fluid or Canada balsam. Such
objects are some thin sections of bone and teeth, some kinds of hairs,
some urinary deposits, &c. It may be stated here, however, that unless
a particular method is known, from repeated trials, to be superior to all
others, the different methods should be adopted with a view of trial, where
the specimens are large enough to divide in this way. Now, although some
sections of bone and teeth show better for being mounted in the dry way, yet
some others show better in Canada balsam ; the choice depending in some
degree on the thickness of the section, and the density of the structure. If
the specimen to be mounted be a rare one, and the quantity small, it should
be examined with the microscope before being permanently mounted. This
may be easily done, both in the dry way and in fluid. Having determined
to mount an object in the dry way, the first step is, to properly cleanse the
specimen, as it will be always found, on examination, that, no matter how
clean an object may appear to the eye, or even with a low power of the
microscope, numerous particles of dust will be found on it.
These, if not removed, may not only prevent the true structure of the
object from being determined, but by the beginner may be mistaken for part
of the structure itself. Indeed, M. Robin recommends the microscopic
study of dust-particles as a preliminary to the proper study of animal
preparations.
Ordinary preparations may be cleansed by soaking them for a few
hours, previous to mounting, in distilled water, or by washing them with a
small syringe and water. Specimens that contain grease, as sections of
bone, &c, may be cleansed by soaking them in sulphuric ether or spirits
of turpentine. After being properly cleansed, the specimen must then be
allowed to dry. If the object be a thin one, it is to be placed upon a plain
glass slide, and covered with a square or circular piece of thin glass, a little
larger than the object. The cover is then pressed firmly down, and fastened
with thick gold-size, or with the compound cement, or the diamond cement,
always being careful to paint on a thin coat of cement, at first, and a thicker
one afterwards.
If the object be too thick to allow the cover to approach the slide, the
intervening space may be filled up by small pieces of paper, card-board, or
thin gutta-percha, having a hole punched out in the centre, a little larger
60 INTRODUCTION.
than the object. These are first to be cemented to the slide ; the object is
then deposited in its place, and the cover cemented down as before.
If the specimen to be mounted be a section of lung, gland, intestine, &c,
and some of these show their structure very well when mounted in the dry
way, one of the different forms of cells before described, may be used. The
depth of the cell being always proportioned to the thickness of the object, it
being desirable to have the surface of the object as near the cover as possi-
ble, the more readily to receive the light. The cover is then to be applied
and cemented with the gold-size.
2. -CANADA BALSAM WITH HEAT.
This method is adopted in mounting thin objects that require to be made
more transparent than they are in the dry state, and at the same time such
as will not be injured by heat. Sections of bone and teeth are often mounted
in this way. The Canada balsam, or, as it is sometimes called, balsam of
fir, used in this manipulation, should be rather old and thick, as it then
requires less heat to harden it than when new and thin.
The best way of keeping it for use, is a tall vial with a narrow mouth.
From this vial the balsam may be dropped on the plain slide or object, and
will be found a better plan of proceeding than that usually recommended,
viz: of keeping the balsam in a wide-rnouthed jar, and taking the desired
quantity by means of a glass rod. In this latter method, it will not only
be found difficult to obtain the sufficiently small quantity required, but the
portion taken will contain a much greater quantity of air-bubbles than when
the balsam is dropped from the vial. The vial should be only about half-
full, and allowed to stand uncorked for a day or so, in order that the air-
bubbles, may rise to the surface, and burst. ,
The object having been properly cleansed and dried, as directed in
mounting objects in the dry way, it is to be deposited in the centre of the
glass slide, and a sufficient quantity of balsam to be dropped on it to com-
pletely cover it. For most objects, one small drop will answer. The slide
is then to be seized by means of an ordinary wire forceps with flat blades
(covered with leather, if desired), and held over the flame of a spirit-lamp;
care being taken to approach the flame gradually; otherwise the slide, if
not broken, will have an infinite number of fine cracks in it, which will
effectually spoil its further use. The slide is to be held over the flame at
short intervals until all traces of air-bubbles are removed, care at the same
time being taken to prevent the boiling of the balsam.
When there is no longer any appearance of air-bubbles, the slide is to be
removed from the flame, and a square or circular piece of thin glass, previ-
ously cleansed and ready, is to be gently warmed, not heated, and pressed
upon the object. The superfluous balsam will escape beyond the thin glass,
CANADA BALSAM. 61
and when cold may be removed with a knife, and subsequently perfectly
cleansed by means of a rag dipped in ether. A modification of this plan
of mounting is, to place the slide containing the balsam upon a piece of tin
kept for the purpose, about four inches square, with the edges bent up, to
prevent the glass from slipping off (a cover to the ordinary seidlitz-powder
box will answer very well), and to hold this over the flame of the lamp by
means of the wire forceps. In this plan, there is less danger of cracking
the glass, but no other advantage.
Still another method is, to have a small table made of tin, supported by
wire legs, sufficiently high to admit the spirit-lamp under it. The slide is
then placed on the table, and heated to the necessary point as before. A
little experience will enable one to judge how much heat is necessary to
sufficiently harden the balsam and dispel the air-bubbles.
Objects may be mounted in Canada Balsam without heat, by dropping the
balsam on the preparation, as before, and allowing it to remain uncovered
for a day or two. In this time, the air-bubbles will usually burst, or will
rise to the surface, where they may be broken by means of a needle-point.
When there are no longer traces of air in the balsam, which may at any
time be discovered by placing the slide under the microscope, and examin-
ing it with a low power, the thin glass is to be warmed, and pressed upon
the object, when the superfluous balsam will escape. The preparation is to
be set aside, and allowed to harden by drying before the escaped balsam
can be removed. This method of course requires a much longer time,
before the object can be properly finished, than when heat is employed, and
is only adapted to cases where heat would injure the object.
When injected specimens are to be mounted in balsam, they should be
placed in cells ; one of these of proportionate size and depth having been
selected, and cleaned by means of ether, or a solution of borax and water,
the object is to be deposited in the cell, and the unoccupied space filled with
the balsam dropped from the vial. The balsam should not overrun the cell,
but rise a little above the level of its edge. The slide is to be set aside for
a day, where it will be free from dust, in order that the air-bubbles may
rise to the surface, and burst. When there is no longer any trace of air in
the balsam, a square or circular cover of thin glass, properly cleaned, and
a little smaller than the outer circumference of the cell, is to be slightly
warmed in the flame of a spirit-lamp, and placed over the cell. If the
cover does not touch the cell at every point, gentle pressure is to be
employed until the superfluous balsam is pressed out.
A sharp-pointed knife may then be used to remove the balsam outside the
cell, when a thin coat of the gold-size is to be applied around the edges of
the thin glass, so as to cement it to the cell. In a few hours or a day,
62 INTRODUCTION.
another and thicker coat of the size is to be applied, or a coat of the asphal-
tum or sealing-wax cement.
Should a bubble of air enter the cell during the operation of adjusting
the cover or removing the balsam around its edges, the cover must be slip-
ped half way off the cell, and another drop of the balsam added.
When the last coat of cement is quite dry, any trace of balsam may be
removed from the slide or cover by means of a linen rag or old cambric
handkerchief, dipped in ether, care being taken not to touch the cement, as
all these are acted on more or less by the ether.
3.-0 EJECTS MOUNTED IN FLUID.
Objects mounted in fluid are usually preserved in some of the different
forms of cells already described ; but some very delicate structures — such as
muscular fibre, fibres of the crystalline lens, &c. — requiring high powers
for examination, should be mounted as fiat (as it is termed) as possible.
With preparations of this order, the following method may be adopted : A
clean plain glass slide having been selected, the object is to be deposited in
the centre: if there are several specimens of the same objects, as several
fibres of muscle, they should be slightly separated by means of a needle-
point. A drop or two of the mounting-fluid is then to be added by means
of a pipette, when the thin glass cover, square or round, is to be placed
gently on the fluid. If the object has escaped to the edge of the thin glass,
it will be much easier to remove the cover, and begin again, than attempt to
push back the specimen with a needle. A very good method to secure the
object in any desired position, is to moisten it with a little water, or spirit
and water, and allow this to evaporate, when the object will adhere to the
surface of the glass. The fluid that escapes beyond the edges of the thin
glass may be removed by means of a camel's-hair pencil, when a very thin
coating of the gold-size is to he applied around the edges of the cover.
When this is dry, another, and sometimes a third coat, must be added in the
same way. When quite dry and hard, the whole slide may be cleaned
with a solution of borax and water. This solution is at once cheap, very
cleansing, and should be always at hand.
The thin glass cell, or the cell made with any of the cements, or the
white-lead, &c, as previously described, may be also used for mounting
this description of objects. When the thjn glass cell can be obtained, this
will be found preferable to all others.
Portions of injected preparations — such as sections of kidneys, liver, intes-
tines, &c. — of different degrees of thickness, require mounting in cells of
proportionate depth. The method is nearly the same as in mounting in
cells with Canada balsam. The object being placed in the cell, the fluid is
to be added either from a vial or by means of a dropping-tube, so as to fill
OPAQUE OBJECTS. 63
the cell completely full without overrunning it. The cover is then to be
gently dropped upon the cell, and the escaped fluid must be carefully absorbed
by means of thin bibulous paper, or, still better, by a camePs-hair pencil.
If a bubble of air has entered the cell, the cover is to be half drawn off,
and more fluid added ; a thin coat of cement is then to be applied, and the
object finished, as already directed.
4. -OPAQUE OBJECTS.
It has been found that some objects, although sufficiently transparent to
allow the light to pass through them, yet show their structure better when
viewed upon a dark ground, or, as it is termed, viewed as opaque objects.
Any transparent object may be made opaque, by turning away the mirror
from the stage of the microscope, or by interposing a dark stop between the
object and the mirror. Both these methods, however, may be troublesome
at times, and objects that require a permanent dark ground may be mounted
opaque by placing a small circle of black paper or blackened silk (court
plaster will answer very well) beneath the object, if it be mounted dry ; or,
if mounted in balsam or fluid, either the paper or silk may be pasted on the
under side of the slide. The object should be covered with thin glass, as
in other methods of mounting, to prevent injury from dust.
Labelling Slides. — The best method of labelling slides, is to write the
name of the object, and the particular point it is intended to exhibit, on the
right-hand side of the slide, with a writing diamond, such as is used in
cutting the thin glass. On the left-hand side of the object may be written
the date of the mounting, the style of the mounting, whether dry or in
balsam, or the name of the fluid used. This will be readily seen to be
desirable information, as when several hundred objects are collected together,
it is impossible to remember the peculiarities of each without some memo-
randum. The advantages of each different mounting may be thus compared
when several specimens of the same object are mounted in different styles,
and this experience may be a guide in future preparations.
Some prefer to cover the slides with paper, either plain or ornamented,
and write the contents of the slide with ink. In pursuing this method, a
circle is cut from the centre of the paper by means of a saddler's-punch a
little larger than the object; the paper is then pasted on by means of the
gum-arabic cement, and the edges turned down over the edge of the slide;
another similar piece of paper is pasted on the opposite side of the slide,
and neatly trimmed off. In this method, there is usually less danger of
breaking the thin glass cover in subsequent handling, but it will be found to
consume considerable time, and, unless very well done, does not make so
64 INTRODUCTION.
neat an appearance as the first method : farther, it cannot be well employed
when any form of deep cell is used.
Cabinets. — For the purpose of preserving microscopical objects free from
dust and from danger of breakage, cabinets of different construction are
employed. Where economy in room is not consulted, those made with
shallow drawers, having a depth of about half an inch, will be found the
most convenient. In these the slides all lie on their flat surfaces, where
any particular one may be more readily reached than when they are placed
on their edges. There is also in the former method less danger of the cells
leaking or their covers being broken.
A favourite method with some, and one occupying much less room, is the
employment of drawers one inch deep, in which racks are placed at proper
distances to receive the slides on their edges. This is the most compact
sort of cabinet, and two or three thousand slides may be thus preserved in
a very small space. The objections to the plan are, the difficulty of readily
finding any desired slide, as you only can see the edges of the glass, and
not the object, and also the danger of breakage to the cells containing fluid.
A method, combining safety and compactness, is the employment of boxes
fitted with racks, and each box capable of containing two dozen slides
placed on their edges. The boxes are then placed on their ends between
permanent partitions in the cabinet; and when arranged and labelled
according to subjects, any particular box or object may be readily reached,
and all the slides while in the cabinet rest on the flat surfaces.
Still another method is, to have boxes made in the shape of books, and
filled with racks, so as to contain two dozen objects. The cover of the box
may be fastened by means of a clasp, and the boxes, when arranged in a
book-case or on the mantel-piece, have a neat appearance. The objects are
kept in the horizontal position, and being arranged in subjects, are very
accessible.
In the preparation of the foregoing Introduction, valuable assistance has
been derived from the following works, to which the student is referred for
more complete accounts of some methods of Manipulation: "Quekett's
Practical Treatise on the Microscope," "Anatomical Manipulation, by Tulk
and Henfrey," and "Du Microscope and et des Injections, par Ch. Robin."
MICROSCOPIC ANATOMY
THE HUMAN BODY
PART I. — THE FLUIDS.
The constituents which enter into the formation of the body, and
by the combination of which the human frame is built up, naturally
resolve themselves into two orders, Fluids and Solids, the latter
proceeding from the former.
In accordance with this natural division of the elements which
enter into the composition of the body, it is intended to divide this
work into two parts : the first of which will treat of those components
of our frame-work which are first formed — the Fluids ; and the
second will be devoted to the consideration of those constituents
which proceed from the fluid elements, viz : the Solids.
Of the fluids themselves, it is difficult to determine upon any sub-
division which shall be altogether without objection ; perhaps the
most practicable and useful division of them which can be made is,
into organized and unorganized.
To the above arrangement of the fluids the following exception
might be taken : all the fluids in the animal economy, it may be said,
are to be considered as organized, inasmuch as their elaboration is
invariably the result of organization. But it is intended that the
words organized and unorganized, when applied to the fluids in
this work, should have a very different, as well as a more precise
signification, and that those fluids only should be called organized
which contain in them, as essential, or, at all events, as constant
constituents, certain solid and organized particles ; while those liquids
5
66
THE FLUIDS.
which are compounded of no such solid matters, as essential portions
of them, should be termed unorganized.
In the first category, the lymph, chyle, blood, mucus, as normal,
and pus, as an abnormal fluid, would find their places together with
the milk and semen. The fluids of this class, it will be seen, belong
especially to nutrition and reproduction, and admit also, naturally,
of arrangement into two series: in the first, those fluids which are
concerned in the nutrition and growth of the species itself would be
comprised — as lymph, chyle, and blood ; and in the second, those
liquids which appertain to the reproduction, nutrition and growth of
the new species, as the milk and semen, would be admitted.
In the second category, viz : that of unorganized fluids, the per-
spirable Jluid. the saliva, the bile, and the urine, as well as probably
the fluid of the pancreas, and of certain other glandular organs,
would be found.
This arrangement of the fluids of the human body might be
represented tabularly, thus :
FLUIDS.
ORGANIZED.
UNORGANIZED.
FIRST SERIES.
Perspirable fluid.
Normal :
Saliva.
Lymph.
Bile.
Chyle.
Urine.
Blood.
Pancreatic fluid (?)
Mucus.
&.C., &c, &c.
Abnormal :
Pus.
SECOND SERIES.
Milk.
Semen.
If the terms organized and unorganized be objected to, the
words compound and simple might take their places, and would well
express the distinction which characterizes the two series of fluids ;
the former appellation being applied to those fluids which are com-
pounded of both a solid and a fluid element, and the latter to those
which do not possess this double constitution.
ORGANIZED FLUIDS.
ART. I. — THE LYMPH AND THE CHYLE.
It will perhaps render the description of the lymph and the chyle
more intelligible, if the observations which we shall have to make on
these fluids are preceded by a short sketch of the lymphatic system
itself. This system consists of vessels and of glands, which are of
the kind, which has been denominated conglobate. The vessels have
many of the characters of veins, commencing as mere radicles, which
unite with each other to form larger trunks, and their interior surface
is provided with valves : they arise from all parts of the system, even
the most remote ; those of the lower extremities and abdominal vis-
cera form by their union the thoracic duct, which, running along the
left side of the spinal column, unites with the left sub-clavian vein,
near its junction with the internal carotid, its contents becoming
mingled with the torrent of blood in that vein. The lymphatics of
the left side of the head and neck, as well as those of the arm of the
corresponding side, unite with the same thoracic duct, in the superior
part of its course. On the right side, however, a smaller separate
duct, formed by the union of the lymphatics of the upper part of that
side of the body, is frequently met with, and this empties itself into
the right sub-clavian vein. All these lymphatic vessels, in their
course, pass through the glands above referred to, and in which the
fluid or lymph contained by them doubtless undergoes further elabora-
tion. The lymphatics are remarkable for their equal and small
diameter, which allows of the passage of the lymph through them by
mere capillary attraction; they are also to be regarded as the chief,
though not the exclusive, agents of absorption in the system, the veins
likewise taking part in this process.
The lymphatics of the upper and lower portions of the body imbibe
and carry along with them the various effete matters and particles
which are continually being given off by the older solid constituents
of our frame, and which are as constantly undergoing a process of
68 ORGANIZED FLUIDS.
regeneration ; these they redigest and reassimilate, into a fluid endowed
with nutritive properties, denominated lymph, and which is poured
into the thoracic duct.
Those lymphatics, however, which arise on the surface of the small
intestines, and which, passing through the mesentery, join the thoracic
duct, have received a special appellation, being called lacteals: this
name has been bestowed upon them on account of the milk-like
appearance of the fluid which they contain, viz : the chyle, a fluid
derived from the digestion of the various articles of food introduced
into the stomach, and which also is emptied into the thoracic duct.
But the lacteals are not always filled with chyle; they are only to
be found so when digestion has been fully accomplished; when an
animal is fasting, they, like other lymphatics, contain merely lymph.
The contents of the thoracic duct likewise vary : it never contains
pure chyle, but during digestion a fluid composed of both chyle and
lymph, the former predominating, and digestion being completed, it is
filled with lymph only.
It follows therefore that, if we are desirous of ascertaining the
proper characters of chyle, our observations should not be conducted
on the fluid of the thoracic duct, but on that of the lacteals themselves.
It is a common error to regard and to describe the contents of that
duct, at all times and under all circumstances, as chyle, and it is one
which has led to the formation of some false conclusions.
We will describe first the lymph, next the chyle, and lastly the
mingled fluid presented to us in the thoracic duct.
The lymph is a transparent colourless liquid, exhibiting a slightly
alkaline reaction, and containing, according to the analysis of Dr. G.
O. Rees, 0' 120 of fibrin, with merely a trace of fatty matter.
When collected in any quantity, and left to itself, the lymph, like
the chyle, separates into a solid and a fluid portion : the solid matter
consists of fibrin, and contains mixed up with its substance numerous
granular and spherical corpuscles, identical with the white globules of
the blood ; the serum is transparent, and contains but few of the cor-
puscles referred to.
The chyle is a whitish, opaque, oleaginous, and thick fluid, also
manifesting an alkaline reaction, and containing, according to the
analysis of the gentleman above mentioned, 0 ' 370 of fibrin, and 3 ' 601
of fatty matter.*
* See article "Lymphatic System," by Mr. Lane, in Cyclopedia of Anatomy and
Physiology, April, 1841.
THE LYMPH AND THE CHYLE. 69
There are present in it solid matters of several kinds.
1st, Minute particles, described by Mr. Gulliver,* and which con-
stitute the "molecular base" of the chyle, imparting to it colour and
opacity : their size is estimated from the 3 @ fo o to the 24^00 0I" an inch
in diameter; they are "remarkable" not only for their minuteness,
but also for "their equal size, their ready solubility in aether, and their
unchangeableness when subjected to the action of numerous other
reagents which quickly affect the chyle globules."
Mr. Gulliver has ascertained the interesting fact, that the milky
appearance occasionally presented by the blood is due to the presence
of the molecules of the chyle. This peculiar appearance of the blood,
which so many observers have observed and commented upon, but
of which none save Mr. Gulliver have offered any satisfactory
explanation, is noticed to occur especially in young and well-fed ani-
mals during digestion ; as also in the human subject, in certain path-
ological conditions, and sometimes in connexion with a gouty diathesis.
2d, Granular Corpuscles, similar to those contained in the lymph,
and identical with the white globules of the blood, but rather smaller
than those, and which will be fully and minutely described in the
chapter on the Blood. Mr. Gulliver, in his excellent article on the
chyle, makes the remark that the magnitude of the globules hardly
differs, from whatever part of the lacteal system they may have been
obtained.
The granular corpuscles are found but sparingly in the chyle of
the inferent lacteals, abundantly in that of the mesenteric glands
themselves, and in medium quantity in the efferent lacteals, and in
the fluid of the thoracic duct.
3d, Oil Globules, which vary exceedingly in dimensions.
4th, Minute Spherules, probably albuminous, the exact size or form
of which it is difficult to estimate, and which are not soluble in aether,
as are those which constitute the molecular base.
Chyle, when left to itself, like the lymph, separates into a solid and
fluid portion : the coagulum, however, is larger and firmer than that
of lymph, in consequence of the greater quantity of fibrin which it
contains; it is also more opaque, from the presence, not merely of
the white granular corpuscles, but principally of the molecules of the
chyle; the serum is likewise opaque, the opacity arising from the
same cause, the peculiar characteristic molecules of the chyle.
* See Appendix to the translation of Gerber's General Anatomy, p. 89.
70 ORGANIZED FLUIDS.
The lymph and the chyle may now be contrasted together. Both
are nutritive fluids, the nutritious ingredients contained in the one
being derived from the redigestion of the various matters which are
constantly thrown off from the older solids, those of the other being
acquired from the food digested in the stomach: the one is a transpa-
rent fluid, containing but little fibrin, a trace only of oil, and but few
white corpuscles; the other is an opaque, white, thick, and oily fluid,
more rich in fibrin, and laden with molecules, white corpuscles, oil
globules, and minute spherules; the one, therefore, is less nutritive
than the other.
It has been asserted that chyle, until after its passage through the
mesenteric glands, would not coagulate; the fallacy of this assertion
has been demonstrated by Mr. Lane*, who collected the chyle pre-
vious to its entrance into those glands, and found that it did coagulate,
although with but little firmness, less indeed than it exhibited subse-
quent to its passage through the glands.
We now come to consider the nature of the contents of the thoracic
duct.
These, as already stated, vary according to the condition of the
animal; thus, if it be fasting, the duct contains only lymph; if,
however, the contents be examined soon after a full meal, they will
be found to present nearly all the characters, physical and vital, of
the chyle, and in addition, especially in the fluid obtained from the
upper part of the duct, a pink hue, said to be deepened by exposure
to the air.
This red colour has been noticed by many observers, and it is now
generally agreed that it arises from the presence in the fluid of the
thoracic duct of numerous red blood corpuscles.
The question is not as to the existence of blood discs in that fluid,
but as to the manner in which their presence therein should be
accounted for, whether it is to be regarded as primary and essential,
or as secondary and accidental.
Most observers agree in considering the presence of blood discs in
the chyle of the thoracic duct as accidental, although they account for
their existence in it in different ways.
The distinguished Hewsonf detected blood corpuscles in the
efferent lymphatics of the spleen, which empty their contents into the
* See Art. " Lymphatic System," loc. cit.
f Experimental Inquiries, part iii. Edited by Magnus Falkoner. London, 1777,
pp. 122. 112. 135.
THE LYMPH AND THE CHYLE. 71
thoracic duct, and in this way he conceived that the fluid of that
vessel acquired its colour.
The accuracy of Hewson's observation, as to the lymphatics of the
spleen containing blood corpuscles, is confirmed by Mr. Gulliver, of
the fidelity, originality, and number of whose remarks on the micro-
scopic anatomy of the animal fluids, it is impossible to speak in terms
of too high praise. Mr. Gulliver detected blood corpuscles in the
efferent lymphatics of the spleen of the ox and of the horse.
Muller, and MM. Gruby and Delafont, attribute the presence of
blood discs in the chyle to the regurgitation of a small quantity of
blood from the sub-clavian vein: if they are really foreign to the
chyle, this is the most probable channel of their ingress.
Mr. Lane thinks that the division of the capillaries, which necessa-
rily takes place in the opening of the duct, allows of the admission
into its contents of the blood discs, which are there found. Such are
the several ways in which it has been suggested that the blood
corpuscles find entrance into the thoracic duct.
Mr. Gulliver has noticed that the blood corpuscles contained in the
chyle are usually much smaller than those taken from the heart of the
same animal, and also, that not more than one-fourth of the entire
number present their ordinary disc-like figure, the remainder being
irregularly indented on the edges, or granulated. The first of these
observations, viz: that which refers to the smaller size of the blood
corpuscles found in the chyle, might be explained by supposing that
those corpuscles were in progress of formation, and that they had not
as yet attained their full development; the other remark, as to the
deformed and granulated character of the corpuscles, might be recon-
ciled with the former explanation, by supposing that some time had
elapsed between the death of the animal and the examination of
the fluid of the thoracic duct. If this manner of accounting for the
condition presented by the blood corpuscles of the chyle should be
proved to be insufficient, which I myself scarcely think it will, then
the only other mode of explaining their appearances is by supposing
that their presence in the chyle is really foreign, and that, soon after
their entrance into that fluid, the blood corpuscles begin to pass
through those changes, indicative of commencing decomposition,
of which they are so readily susceptible.
Leaving, however, for the present the question of the origin of the
red corpuscles of the blood, which will have to be more fully discussed
hereafter, we will in the next place bestow a few reflections upon the
72 ORGANIZED FLUIDS.
origin of the white corpuscles: into this subject, however, it is not
intended to enter at any length at present, but merely to make such
observations as seem more appropriately to find their place in the
chapter on the Chyle and Lymph.
It has been noticed that the white corpuscles occur in very great
numbers in the chyle obtained from the mesenteric and lymphatic
glands; this observation has led to the supposition that the white
corpuscles are formed in those glands.
Upon this question, as upon so many others, Comparative Anatomy
throws much light. It has been ascertained that the glands referred
to have no existence in the amphibia and in fishes ; in birds, too,
they are only found in the neck. Thus it is evident, that the lymphatic
glands, however much they may contribute to the formation of the
white corpuscles, are not essential to their production.
Corpuscles, very analogous to those of the chyle and the lymph,
are found in vast quantities in the fluid of the thymus gland in early
life : these corpuscles Hewson considered to be identical with the
globules of those fluids, and therefore he regarded the thymus gland as
an organ of nutrition, and as an appendage to the lymphatic system.
In this opinion he has been followed by Mr. Gulliver. That it is an
organ of nutrition, adapted to the special exigencies of early life, there
can be no doubt ; but that it is an appendage of the lymphatic system,
and that the globules with which it so abounds are the same as those
of the lymph and chyle, admits of much diversity of opinion.
The globules of the thymus have undoubtedly striking points of
resemblance with the corpuscles so frequently alluded to; they have
the same granular structure; they are, like them, colourless, and to
some extent they comport themselves similarly under the influence of
certain reagents.
There are points, however, of dissimilarity as well as of resemblance;
thus they are usually very much smaller than the lymph corpuscles,
they do not undergo any increase of size when immersed in water, and
acetic acid does not disclose the presence of nuclei.
But, above all, the corpuscles of the thymus differ from those of the
lymph and chyle in their situation; those of the latter fluids are
always enclosed in vessels in lymphatics, or lacteal lymphatics ; while
those of the former fluid, that of the thymus gland, are extravascular,
lying loosely in the meshes of the cellular tissue which forms the
foundation of the substance of the gland itself.
Now, it is impossible to conceive that solid organisms of such a size
THE LYMPH AND THE CHYLE. 73
as the corpuscles of the thymus can enter the lymphatics bodily ; if
they are received into the circulation at all, they must first undergo
a disintegration and dissolution of their structure.
Both Mr. Gulliver and Mr. Simon* regard the corpuscles of the
thymus as cytoblasts; the former, however, believes that before their
development as cytoblasts they enter the circulation, while the latter con-
ceives that they are developed in the gland itself into true nucleated cells.
It is difficult to suppose, with Mr. Simon, that the small and uniform
granular corpuscles of the thymus are developed into the large, complex
and curiously constituted true secreting cells of that gland.
Whether this be the case or not, however, it would appear that
Mr. Simon has fallen into a certain amount of error in his account of
the structure of the thymus gland, and also of other analogous glands, as
well as in the generalizations deduced by him therefrom.
Thus, Mr. Simon states, that in early life there exists in the thymus
gland " no trace whatever of complete cells ;" that it is only in later
life that nucleated cells are formed, and that these are developed out
of the granular corpuscles already referred to, and which are alone
present in the gland in the first years of its existence. The same
statements are applied to the thyroid body.
But Mr. Simon does not rest here : he regards the long persistence
of the corpuscles, which he states are to be found in all those glands
which secrete into closed cavities, in the condition of cytoblasts, as
constituting a remarkable and important distinction between the glands
in question and the true secreting glands which are furnished with
excretory ducts.
These observations are to a considerable extent erroneous, as is
proved by the fact that true nucleated cells are to be met with
abundantly in the thymus gland of still-born children, and also in
the thyroid body and supra-renal capsule ; in the last, indeed, almost
every cell is nucleated.
On this supposed essential structural distinction between the true
glands which are furnished with excretory ducts, and those anomalous
ones which are destitute of such ducts, Mr. Simon founds some
general deductions.
It is known that the functions performed by the glands without
ducts are of a periodic and temporary character, while those discharged
by the true glands are of a permanent and constant nature.
* Prize Essay on the Thymus Gland. London, 4to., 1846.
74 ORGANIZED FLUIDS.
It is also considered by some physiologists that the nucleus of every
nucleated cell is the only true and necessary secreting structure.
These views of the nature of the functions performed by the
anomalous glands, and of the importance of the nucleus, being adopted
by Mr. Simon, he thence draws the inference that the cytoblastic
condition of the cells of the thyroid, thymus, and other analogous
glands, is precisely that which is required by organs which are called
only into action periodically, and in which great activity prevails at
certain periods.
This theory is ingenious, but it has been seen that the main fact
upon which it rests is for the most part erroneous ; and, the basis of
the theory being removed, the theory itself must fall.
In order that it may be seen that the opinions entertained by
Mr. Simon, in his Essay on the Thymus, have not been over-stated, I
will introduce a few passages therefrom :
"Thus, while the completion of cells, within the cavities of the
thyroid gland, is assuredly a departure from the habitual state of that
organ, and probably the evidence of protracted activity therein ; it is
yet just such a direction as may serve even better than uniformity to
illustrate the meaning of the structures which present it; for it
shows, beyond dispute, that the dotted corpuscles are homologous with
the cytoblasts of true glands." (p. 79.)
"In the thymus one would at first believe a similar low stage of
cell development to be universal ; for in examining the contents
of the gland in early life, one finds no trace whatever of complete cells.
The dotted corpuscles are undoubtedly quite similar to those which
we have recognised as becoming the nuclei of cells in the thyroid
body, and in other organs ; there is abundant room for conjecturing
them to be of a correspondent function — to be, in fact, true cytoblasts;
■but the arguments for this point cannot be considered quite conclu-
sive, without some additional evidence."
" The completion of a cell, from the isolation of so much of the
secreted product as is collected round each cytoblast, is a very frequent
secondary process. In the true glands it is very frequent, in those
without ducts exceptional." (p. 84.)
With one other remark on the corpuscles of the thymus, we will
conclude this short chapter; mixed up with those corpuscles are
frequently to be noticed many nucleated globules, in every way similar
THE LYMPH AND THE CHYLE. 75
to the white corpuscles of the blood, but very distinct from the true
cell corpuscles of the gland; the nucleus of these white globules is of
nearly the same size as the dotted corpuscles themselves. Is there
any relation between this coincidence in size ?
We now pass to the consideration of the most important fluid in
the animal economy, viz: the blood.
76 ORGANIZED FLUIDS.
[The lacteals have their origin in the villi of the intestines, while the
lymphatics originate throughout the body in the various tissues and organs
of which it is composed.
These latter vessels are arranged in a superficial and deep set ; the
superficial running underneath the skin, or under the membranous coats,
immediately enveloping the organs in which they are found, while the deep
lymphatics usually accompany the deep-seated blood vessels. They
usually exceed the veins in number, but are less in size, and anastomose
more frequently than the accompanying veins. The origin of the lymph-
atics may be either superficial or deep : in the first mode, they usually arise
in the form of net-works, or plexuses, out of which single vessels emerge
at various points, and proceed directly to the lymphatic glands, or to join
larger lymphatic vessels.
These plexuses consist of several strata, becoming finer as they approach
the surface, both in the calibre of the vessels and closeness of reticulation.
When the lymphatics have a deep origin, their precise mode is not so easily
made out : it is probably the same as when they arise superficially.
STRUCTURE.
The lymphatic vessels, in their structure much resembling veins, have
thinner and more delicate coats ; some are quite transparent.*
For an account of structure of lacteals, see page 492.
The medium-sized and larger lymphatic vessels, according to Mr. Lane,f
have three coats ; viz : an internal, a middle or fibrous, and an external,
one, analogous to the external or cellular coat of the blood-vessels.
The inner tunic is thin, transparent, and elastic, but less elastic than the
others, being the first to give way when the vessel is unduly distended : like
the blood-vessels, it is lined with a layer of scaly or tesselated epithelium,
as in the blood-vessels. The middle or fibrous coat is very elastic, and
consists of longitudinal fibres having the characters of the plain involuntary
muscular fibres, freely mixed with fibres of cellular tissue. Herbst, Henleij:
and others, describe, with these longitudinal fibres, others of transverse and
oblique direction : these are very few in number, the great majority being
longitudinal. The external or cellular coat is elastic, and composed of
interlaced fasciculi, of areolar tissue, mixed with some elastic fibres.
The lymphatics receive vasa vasorum, which ramify in their middle and
outer coats; nerves distributed to them have not yet been discovered, al
though their existence has been inferred on physiological grounds. The}
are also endowed with vital contractility.
* Quain's "Anatomy," 5th edition, by Sharpey and Quain.
f "Cyclop, of Anatomy and Physiology," art. "Lym. System."
I Henle, " Algemeine Anatomie," Leipsic, 1841.
THE LYMPH AND THE CHYLE. 77
The lymphatics and lacteals are supplied with valves in the same manner
as the veins, and for like purposes. They usually consist of two semi-lunar
folds, but variations occasionally occur. They are altogether wanting in
the reticularly arranged vessels, which compose the plexuses of origin
before spoken of; but where they exist, they follow one another at shorter
intervals than in the veins.
Mr. T. Wilkinson King (Guy's Hospital Reports, April, 1840,) has calcu-
lated the entire number of valves in the lymphatic system at 30,000, while
the veins only contain about 5,000.
The lymphatics of fish and amphibia are usually destitute of valves, and
may be injected from the trunks : in birds, valves are less numerous than
in the lymphatics of the mammiferous animals.
" No lymphatics have yet been traced in the substance of the brain or spinal cord,
though they exist in the membranous envelopes of these parts, nor have they been
detected within the eye-ball, or in the placenta or foetal envelopes. Although no
absorbent or open orifices have been discovered in the lacteals or lymphatics, yet it
is probable, that both the lymph and chyle corpuscles are developed as cells within
the vessels; according to one view, these corpuscles of lymph, may be developed
from the liquid part of the lymph, which serves as a blastema. In this case, the
nuclei may be formed by aggregation of matter round nucleoli, which again may be
derived as germs from other cells; or, as Henle is disposed to think, two or more
fat particles may unite to form a nucleus ; upon another view, it may be conceived
that these corpuscles are formed on the inner surface of the walls of their containing
vessels, as epithelium or mucous corpuscles are produced on their supporting mem-
brane, and that this process may be connected with the absorption of lymph or
chyle with the vessels, in the same manner as secretion into a gland-duct, or other
receptacle, is accompanied by the formation and detachment of cells."*
MANIPULATION-
To procure lymph and chyle quite pure, it is necessary to take the first
from the lymphatic glands, and the second from the lacteals themselves.
Wagner has found dogs the best subjects for such experiments in compara-
tive anatomy, and on the surface of the liver and spleen, are commonly
found turgid lymphatic vessels, from which pure lymph may be obtained.
It may also be obtained quite pure by opening the thoracic duct of an
animal that has fasted for some time before being killed.
The chemical analysis of chyle usually quoted, is that of the ass, made
by Dr. Rees, and of the cat, made by Nasse.
Dr. Rees has examined the fluid contained in the thoracic duct of a
human subject, a criminal, an hour and a half after execution. From the
small quantity of food taken for some hours before death, the fluid must
* Quain's "Anatomy," by Sharpey and Quain, 5th edition.
78 ORGANIZED FLUIDS.
have consisted principally of lymph. It had a milky hue, with a slight tinge
of buff. Its analysis, compared with that of the chyle of the ass, given in
the text, shows less water, more albumen, and much less fat.
The chyle-corpuscles are most numerous in the chyle taken from the
mesenteric glands.
The lymph corpuscles, though closely resembling the colourless corpuscles
of the blood, hereafter described, are rather less in size, and not so uniformly
round.
The globules of chyle and lymph, also, differ in structure from the pale
globules of blood : in the last, two, three or four nuclei are easily seen when
the envelope is made more or less transparent, by acetic, sulphureous, citric,
or tartaric acid. But globules of lymph and chyle, like the nuclei of red
corpuscles of blood, are only rendered more distinct, and slightly smaller by
any of these acids ; so that the central parts present no regular nuclei, or
divided nucleus, such as are contained in pale globules of blood. In the
larger lymphatics and thoracic duct, are found corpuscles identical in size
and structure to the pale corpuscles of blood. When fresh, the corpuscles
of lymph and chyle swell on being mingled with pure water, as does the
nucleus of blood corpuscle. Mixed with a strong alkali, or neutral salt,
the globule becomes partially dissolved, mis-shapen, or fainter, forming a
ropy and tenacious compound with the fluid. According to Gulliver, the
average measurements of the corpuscles of lymph and chyle are the same,
viz : -rJW of an English inch. Mr. Gulliver measures the colourless cor-
4 6 0 0 o
puscles of the blood 3 ^V o °f an mc^' or about 1 larger than the lymph and
chyle corpuscles.*
For the purposes of examination and study of the corpuscles of lymph
or chyle, it is necessary to place a very small drop obtained from either of
the sources already mentioned, on a plain glass slide, wiped perfectly clean
and dry, and cover it immediately with a piece of thin glass. It is then
ready for examination with a ith or ith-inch object glass. Sometimes the
corpuscles will be better observed after the lymph is diluted with serum.
After examination in this way, the different reagents may be applied, by
introducing any one of them by means of a pipette upon the edge of the thin
covering glass ; by means of capillary attraction, the reagent will gradually
insinuate itself under the glass, and its effects must be constantly observed
with the microscope.
Plate LXX., fig. 1, exhibits corpuscles of lymph.
Fig. 2, exhibits corpuscles of chyle.
Plate LXXIII., fig. 1, exhibits a lymphatic gland, and lymphatic vessels.]
* Hewson's Worn uied by Gulliver, published for Sydenham Society, page 253.
THE BLOOD. 79
ART. II. — THE BLOOD.
Of all the fluids in the animal economy, the most interesting and
the most important is the Blood : and it is an appreciation of this fact
which has led to the concentration upon its study, in times past as
well as present, of the powers of a host of able and gifted observers,
whose labours have not been without their reward.
The knowledge of this fluid acquired by the early physician was
of a very limited character, it being confined to the observance of a
certain number of external and obvious appearances, such as the
colour, consistence, and form of the effused blood. Limited as this
knowledge was, however, compared with that which, in our favoured
day, we enjoy, it was not without its practical utility.
More recently, the chemist, who is in these times extending in all
directions so rapidly the boundaries of his domain, has cast upon this
peculiar portion of it a flood of light. Who, to look upon a dark and
discoloured mass of blood, could imagine that the magic power of
chemistry could reveal in it the existence of not less than forty distinct
and essential substances ?
Lastly, the micrographer, with zeal unweariable, has even outstripped
the progress of his rival the chemist, and brought to light results of the
highest importance. It is these results that in this work we have
more especially to consider.
In the following pages we shall have to treat of the blood under
various aspects and conditions ; we shall have to regard it alive and
dead, circulating within its vessels, and motionless without them ; as
a fluid and as a solid; healthy and diseased; or, in other words, we
shall have to consider the blood physiologically, pathologically, and
anatomically.
* Those who wish to learn the comparative size of the hlood corpuscles in the
different vertebrate animals, may find a very complete table of their measurements
in the "Proceedings of the Zoological Society, No. 152," carefully prepared by Mr.
Gulliver; or " He wson's Works," published for the Sydenham Society, and edited by
Mr. George Gulliver, pp. 237 — 243: or "Gerber's General Anatomy," edited by
Gulliver — Appendix, pp. 31 — 84.
80 ORGANIZED FLUIDS.
The blood may be defined as an elaborated fluid, having usually
a specific gravity of about 1055, that is, heavier than water; in
mammalia and most vertebrate animals, being of a red colour, but
colourless in the invertebrata;* circulating in distinct sets of vessels,
arteries, and veins; holding in solution, all the elements of the animal
fabric — fibrin, albumen, and serum, together with various salts and
bases, and in suspension, myriads of solid particles, termed globules. f
The blood would thus appear to be the grand supporter and
regenerator of the system; in early life, supplying the materials
necessary for the development of the frame, and, in adult existence,
furnishing those required for its maintainance : hence "the blood"
has been figuratively called "the life."
COAGULATION OF THE BLOOD, WITHOUT THE BODY.
The first change which the blood undergoes subsequent to its
removal from the body consists in its coagulation. This phenomenon
has been denominated emphatically, "the death of the blood," because,
when it has once occurred, the blood is thereby rendered unfit to
maintain the vital functions, and there is no known power which can
restore to it that faculty.
Although the word coagulation is usually applied generally to the
blood, yet it not to be understood that the whole of the mass of that
fluid undergoes the change of condition implied by the term coagula-
tion, which affects but a single element of the blood, viz : the fibrin.
The precise circumstances to which the coagulation of the blood is
due, have never as yet been satisfactorily explained and determined.
Some have conceived that it resulted from the escape of a vital air or
essence. Much has been said and written upon this "vital principle,"
and, it seems to me, with very little profit. It would be more philo-
* Miiller states that the quantity of blood in the system varies from eight to
thirty pounds, and Valentin found that the mean quantity of Wood in the male adult,
at the time when the weight of the body is greatest, viz : at thirty years, is about
thirty-four and a half pounds, and in the adult female, at fifty years, when the weight
of the body in that sex is at its maximum, about twenty-six pounds. According
also to Miiller, the specific gravity of the blood varies from 1-527 to 1 *057 ; arterial
blood is lighter than venous.
f In one vertebrate animal, a fish, Branchiostoma lubricum Costa, the blood is
colourless, and in the most of Annelida it is red ; the red colour, however, exists in
the liquor sanguinis, and not in the blood corpuscles.
THE BLOOD. 81
sophical, I think, to regard animal life not as an essence, or aether, but
as the complex operation of nicely-adjusted scientific adaptations and
principles. According to this view, the human frame in health would
be comparable (and yet, withal, how incomparable is it!) to a finely-
balanced machine, in which action and reaction are proportionate,
and in disease disproportionate, the injury to the machine being
equivalent to the disproportion between the two forces.*
The coagulation of the blood, in some degree, doubtless depends
upon the operation of the following causes, each contributing in a
greater or lesser degree to the result ; namely, the cessation of
nervous influence, the abstraction of caloric, the exercise of chemical
affinity between the particles of fibrin, and, lastly, a state of rest:
between motion and life a very close connexion appears to exist.f
Formation of the Clot.
A portion of blood having been abstracted from the system, and
allowed to remain for a few minutes in a state of quiesence, in a basin
or other suitable vessel, soon manifests a change of condition. This
consists in the separation of the fibrin and globules of the blood, which
go to form the clot, from the serum, which holds in solution the
various salts of the blood. In this way a rude and natural analysis is
brought about; the fibrin, being heavier than the serum, falls to the
bottom, and, by reason of its coherence and contractility, forms a
compact mass or clot, the diameter of which is less than that of the
vessel in which it is contained ; while the lighter serum floats on the
top and in the space around the clot.
Now, the only active agent in this change in the arrangement of
the different constituents of the blood, is the fibrin; and although the
globules of the blood constitute a portion of the clot, yet they take no
direct part in its formation, and their presence in it is thus accounted
for; the fibrin, in coagulating, assumes a filamentous and reticular
structure, in the meshes of which the globules become entangled,
and thus are made to contribute to the composition of the clot, the bulk
of which they increase, and to which they impart the red colour.
It was an ancient theory that the clot was formed solely by the
* It is hoped that the preceding brief remarks will not expose the writer to the
charge of being a Materialist ; between animal life and mind an essential distinction
exists.
f " Fresh blood, if exposed to a very low temperature, freezes, and may in that
state be preserved, so as to be still susceptible of coagulation when thawed." — Mullek.
6
82 ORGANIZED FLUIDS.
union of the globules with each other. The fallacy of this opinion is
easily demonstrated by the two following decisive experiments:
The first is that of Muller, on the blood of the frog, who separated,
by means of a filter, the globules from the fibrin, the latter still form-
ing a clot, although deprived of the globules. This experiment is
not, however, applicable to the blood of man, or of mammalia in
general, the globules in these being too small to be retained by the
filter. The second expedient is, however, perfectly suited to the
human blood. It is well known that if blood, immediately after its
removal from the body, be stirred with a stick, the fibrin will adhere
to it in the form of shreds ; the blood being defibrinated by this means,
the globules fall to the bottom of the basin in which the blood is con-
tained, on account of their gravity; but they do not cohere so as to
form a clot, remaining disconnected and loose.
It is difficult to determine the exact time which the blood takes to
coagulate, because this coagulation is not the work of a moment; but,
from its commencement to its completion, the process occupies
usually several minutes. The first evidence of the formation of the
clot, is the appearance of a thin and greenish serum on the surface of
the blood, in which may be seen numerous delicate fibres, the
arrangement of which may be compared to that of the needle-like
crystals contained in the solution of a salt in which crystallization has
commenced. Estimating, however, the coagulation neither from its
commencement nor from the complete formation and consolidation
of the clot, but from the mean time between these two points, it will
generally be found that healthy blood coagulates in from fifteen to
twenty minutes.
In diseased states of the system, however, the time occupied in the
coagulation of the blood, or, in other words, in the formation of the
crassamentum, or clot, varies very considerably; and it is of much
practical importance that the principle which regulates this diversity
should be clearly understood.
In disorders of an acute, active, or sthenic character, in which the
vital energies may be regarded as in excess — as, for instance, in
inflammatory affections, in pneumonia, pleurisy, acute rheumatism,
and sanguineous apoplexy : in febrile states of the system, as in the
commencement of some fevers, as in ague, plethora, and as in utero-
gestation — the blood takes a much longer time than ordinary to
coagulate, no traces of this change in the passage of the blood from a
fluid to a solid state being apparent until from sixteen to twenty
THE BLOOD.
83
minutes have elapsed. This length of time may be accounted for,
by supposing that, in the affections named, the blood is endowed with
a higher degree of vitality, and that therefore a longer period is
required for its death to ensue ; or, in other words, if the expression
may be allowed, that the blood in such cases dies hard. On the con-
trary, in disorders of a chronic, passive, or asthenic character, in all
of which there is deficiency of the vital powers — as in typhus, anemia,
chlorosis — the blood passes to a solid state in a much shorter period
than ordinary, even in from five to ten minutes. In these cases the
vitality of the blood is very feeble, and it may be said to die easily.
A remarkable difference is likewise observable in the characters of the
clot formed in the two classes of disorders named ; in the first it is
firm, and well defined; in the second, soft, and diffluent.* To this
subject we shall have occasion again to refer, more at length.
Fibrin, if left at rest for a time, undergoes a softening process, and
breaks up into an extremely minute granular substance. This
softening of the fibrin has been improperly confounded with suppura-
tion; the softened mass, however, may be distinguished from true
pus by the almost complete absence of pus globules. This peculiar
change in the condition of the fibrin has been noticed to occur both
in TDlood contained within and without the body, and large softened
clots of it are not unfrequently encountered in the heart after death.
The process always commences in the centre of these clots.
Formation of the Buffy Coat of the Blood.
Surmounting the coloured portion of the clot is observed, in blood
taken from the system in inflammatory states, a yellowish-green
stratum ; this constitutes the buffy or inflammatory crust, the presence
of which was deemed of so much importance by the ancient physician,
and which is indeed not without its pathological value. This crust
consists of fibrin deprived of the red globules of the blood; and its
mode of formation is thus easily and satisfactorily explained. Of the
constituents of the blood, the red globules are the heaviest; now,
supposing that no solidification of any one element were to take place,
these, of course, would always be found occupying the lowest position
in the containing vessel ; the fibrin would take the second rank, and the
serum the third : but such, under ordinary circumstances, not being
* It is to be remarked, that the clot is not of equal density throughout, but that
its lower portion is invariably softer than the upper, and this is accounted for by the
fact of its containing less fibrin.
84 ORGANIZED FLUIDS.
the case, and the fibrin coagulating so speedily, the globules become
entangled in its meshes before they have had sufficient time given
them to enable them to obey fully the impulse derived from their
greater specific gravity ; and thus no crust is formed. In blood drawn
in inflammations, however, this coagulation, as already stated, pro-
ceeds much more slowly; and thus time is allowed to the globules to
follow this impulse of the law of gravity to such an extent, as that
they fall a certain distance, about the sixteenth of an inch, usually,
below the surface of the fibrin, before its complete coagulation averts
their further progress; and a portion of which is thus left colourless,
which constitutes the buffy and so-called inflammatory crust of the
blood. But there are other considerations to which it is necessary
to attend, and which contribute to the formation of the buffy coat.
One of these is the greater relative amount of fibrin which
inflammatory blood contains.
A second is the increased disposition, first pointed out by Pro-
fessor Nasse, which the red corpuscles have in inflammatory blood to
adhere together and to form rolls, and the consequence of which is
that they occupy less space in the clot.
A third additional consideration, to which it is necessary to attend,
in reference to the formation of the inflammatory crust, is the density
of the blood, which bears no exact relation to the amount of fibrin,
but depends rather upon the quantity of albumen which it contains.*
The greater the density of the blood, the longer would the globules
take to subside in that fluid ; and the less its density, the shorter would
that period be. Now, inflammatory blood is usually of high density,
while with that of feeble vitality, the reverse obtains. Thus, were it
not for the fact, that in blood in the first state, coagulation is slow, and
in the second quick, the blood of weak vital power would be that in
which, a priori, we should expect to see the buffy coat most frequently
formed ; but the much greater rapidity in the coagulation of the blood
more than counterbalances the effect of density.
The blood, then, may be so dense, that although at the same time
it coagulates very slowly, yet no inflammatory crust be formed, the
patient from whom the blood is extracted labouring all the while
under severe inflammation. An ignorance of this fact has been the
source of many great and perhaps fatal errors, on the part of those
* It has been remarked, that in albuminuria, in which a considerable portion of
the albumen of the system passes off with the urine, the blood possesses a very
feeble density.
THE BLOOD. 85
physicians who have been used to regard the presence of the buffy
coat as an undoubted evidence of the existence of inflammation, and
its absence as indicating immunity therefrom. It has been remarked
that, in the first bleedings of pnemonic patients, the blood often wants
the buffy coat; this is attributed to its greater density, and which is
found, to diminish with each succeeding abstraction of blood; so
that if inflammation be present, the characteristic coat is usually
apparent also after the second bleeding.
The conditions, then, favourable to the formation of the buffy coat,
are a mean density of the blood, slow coagulation, excess of fibrin,
and increased disposition to adherence on the part of the red corpuscles.
Other circumstances doubtless exist, which in a minor degree affect
the formation of the crust : such as the density of the globules, and
the qualities of the fibrin itself. Into these it is unnecessary to enter,
as they do not vitiate the accuracy of the general statements.
The Cupping of the Clot.
At the same time that the crassamentum exhibits the buffy coat, the
upper surface of the clot is very generally also cupped. This cupping
of the clot arises from the contraction of that portion of the fibrin
which constitutes the buffy stratum, and which contraction operates
with greater force on account of the absence in it of the red corpuscles
of the blood. The degree to which the clot is cupped, therefore,
probably is in direct relation with the thickness of the crust. Its
presence was also regarded as an indication of the existence of
inflammation, the amount of cupping denoting the extent of inflam-
mation. This sign is not, however, any more than that afforded by
the buffy coat, to be considered as an invariable criterion of the
existence of inflammation.*
* Professor Nasse has pointed out a mottled appearance which is frequently
observed to precede the formation of the buffy coat, and the existence of which he
states to be quite characteristic of inflammatory blood. This appearance is produced
in the following manner : after the lapse of a minute or two, a peculiar heaving
motion of the threads or rolls formed by the union of the red corpuscles with each
other is observed to take place ; this results in the breaking up of the rolls, the
corpuscles of whieh now collect into masses, leaving, however, intervals between
them, and which become filled with fibrin ; now, it is the contrast in colour between
this fibrin and the masses of red corpuscles which occasions the blood in coagulating
to assume the mottled aspect referred to.
86 ORGANIZED FLUIDS.
COAGULATION OF THE BLOOD, IN THE VESSELS AFTER DEATH.
The coagulation, or death, which we have described as occurring
in blood abstracted from the system by venesection, takes place like-
wise— the vital influence which maintains the circulation being
removed — in that which is still contained within the vessels of the
body, although in a manner less marked and appreciable.
As also in the case of the blood withdrawn from the system, the
time occupied in the coagulation of that which is still enclosed in its
own proper vessels, varies very considerably. This difference
depends partly upon the circumstances under which the patient has
died, whether he has been exhausted or not by a previous long and
wasting illness, and partly upon temperature and, perhaps, certain
electric states of the atmosphere. In all instances, however, a much
longer period is required for the production of coagulation in blood
not removed from the body, than in that which has been withdrawn
by bleeding; this change in its condition being seldom effected, in the
former instance, in a shorter period than from twelve to twenty-four
hours subsequent to decease ; although occasionally, but rarely, it may
occur at periods either earlier or later than those named.
Signs of Death. — It has already been stated, that blood once coag-
ulated is rendered unfit for the purposes of life, and that no known
means exist capable of restoring to coagulated blood its fluid state, so
as to render it once again suited to play its part in the maintenance
of the vital functions. The accuracy of these statements is attested
by physiology, which demonstrates to us that a fluid condition is
necessary to the blood, for the correct performance of its allotted
functions. It follows, then, from the foregoing, that a coagulated
state of the blood, not in a single vessel indeed, but in the vessels of
the system generally, affords a certain indication that death has
occurred, and that therefore a return to life has become impossible.
It has ever been an object of the highest importance to distinguish
real from apparent death; and anxious searches have been instituted
in the hope of discovering some certain sign whereby the occurrence
of death is at once signalized. Hitherto this inquiry has been unsuc-
cessful; and it could hardly have been otherwise; for before the
physiologist will be able to determine the precise moment when life
ceases, and death begins, he must know in what the life consists, for
death is but the negation of life. It is probable that the mystery of
life will never be revealed to man ; if, indeed, it be any thing more
THE BLOOD. 87
than, as already hinted, the result of the combined operation of vari-
ous chemical and physical laws appertaining to matter.
Although no one single sign has hitherto been discovered indicative
of death at the moment of its occurrence, yet several appearances
have been remarked some time after death, all of which are of more
or less value in determining so important a point. Independently of
the cessation of respiration and circulation, the presence of muscular
rigidity, some other changes have been noticed to occur in different
parts of the human body soon after the extinction of life; as, for
instance, in the eye, and in the skin: these are mostly, however,
symptomatic of incipient decomposition, and the time of their acces-
sion is very uncertain: they likewise affect parts, the integrity of
which is not essential to life. A fluid state of the blood, on the con-
trary, has been shown to be indispensable to life; so that the change
which it undergoes in the vessels of the body so quickly after death,
may be employed with much advantage and certainty in determining,
in doubtful cases, whether life has become extinct or not.
It is by no means difficult to establish the fact of the coagulation
of the blood in the vessels after death. If a vein be opened, as in the
ordinary operation of bleeding, in a person who has just died, the
blood will issue in a fluid state, as in life ; but it will not leap forth in
a stream. If a little of the blood, thus procured, be preserved in a
small glass, we shall soon remark the occurrence of coagulation in it,
from which we shall know that the fibrin within the vessels has not
as yet assumed a solid form. If we repeat this operation at the end
of about eighteen hours, we shall obtain only a small quantity of red-
dish serum, in which, on being set aside for a time, no crassamentum
will be found, the only change occurring in this serum consisting in
the subsidence of the few red globules which were previously sus-
pended in it, and which now form, at the bottom of the glass, a loose
and powdery mass. By this experiment, which may be repeated on
several veins, and even on an artery, we have clearly established the
fact of the coagulation of the blood within the vessels of the body,
and therefore have ascertained, in a manner the most satisfactory,
that life is extinct.
In some instances, the blood is said to remain fluid after death:
this statement is not strictly correct, as a careful examination of such
blood will always lead to the detection of some traces of coagulation.
To the subject of the fluid condition of the blood after death, we shall
have hereafter to return, in treating of the pathology of the blood.
88 ORGANIZED FLUIDS.
When it is recollected that the heat of some climates, and the laws
and usages of other countries, compel the interment of the dead a
very few hours after decease, the importance of this inquiry will
become apparent ; and the value of any sign which more certainly
indicates death than those usually relied upon in determining this
question, will be more fully appreciated.
It cannot be doubted but that, from the insufficient nature of the
signs of death usually regarded as decisive, premature interment does
occasionally take place ; and it is probable that this occurrence is far
less unfrequent than is generally supposed, and that for each discov-
ered case, a hundred occur in which the fatal mistake is never brought
to light, it being buried with the victim of either ignorance or care-
lessness.*
We have now to proceed to the anatomical consideration of the
blood ; we have to pass to the description of the solid constituents of
that fluid, the globules ; to describe their different kinds, their form,
their dimensions and their structure ; their origin, their development,
and their destination, their properties, and their uses.
THE GLOBULES OF THE BLOOD.
The blood is not an homogeneous fluid, but holds in suspension
throughout its substance a number of solid particles, termed globules.
These serve to indicate to the eye the motion of the blood ; and were
it not for their presence, we should be unable to establish, micro-
scopically, the fact of the existence of a circulation, to mark its course,
and to estimate the relative speed of the current in arteries and veins
under different circumstances.
These globules are so abundant in the blood, that a single drop
contains very many thousands of them, and yet they are not so minute
but that their form, size, and structure, with good microscopes, can
be clearly ascertained and defined. They are not all of one kind, but
three different descriptions have been detected — the red globules, the
white, and certain smaller particles, termed molecules. We shall
take each of them in order; and notice, in the first place, the red
globules, f
* The coagulation of the blood may he retarded or altogether prevented by its
admixture with various saline matters : to this point we shall have occasion to refer
more fully hereafter.
f Malpighi first signalized the existence of the red globules in the blood, so far
back as 1665: he regarded them as of an oily nature. The words in which this dis~
THE BLOOD. 89
THE RED GLOBULES.
The number of red globules existing in the blood surpasses by many-
times that of the white. To the sight, when seen circulating in this
fluid, they appear to constitute almost the entire of its bulk. We
shall now have to consider their form, the size, the structure, and the
properties by which they are characterized.
Form. — In man, and in most mammalia, the red blood corpuscles
are of a circular, but flattened, form, with rounded edges, and a central
depression on each surface, the depth of which varies according to
the amount of the contents of each globule.* Such is the normal form
of the blood discs, or the shape proper to them while circulating in
the blood of an adult. (See Plate I. fig. 1.) In that of the embryo,
the depression is wanting, and the globules are simply lenticular. f
The blood globules, however, like all minute vesicles, possess the
properties of endosmosis and exosmosis. These principles depend for
their operation upon the different relative density of two fluids, the
one external to the vesicle, the other internal. When these two fluids
are of equal density, then no change in the normal form of the vesicles
occurs : when, however, the internal fluid is of greater density than
the external, then an alteration of shape does take place ; endosmosis
ensues, in which phenomenon a portion of the liquid without the
vesicle passes through its investing membrane, and thus distends and
modifies its form. Lastly, when a reverse disposition of the fluids
exists, a contrary effect becomes manifested; exosmosis is the result;
this implies the escape of a portion of the contents of the vesicle into
the medium which surrounds and envelopes it. The operation of
covery was recorded were as follow: "Sanguineum nempe vas in omento hystricis . . .
in quo globuli pinguedinis propria figura terminati rubescentes et corallorum rubrorum
vulgo coronam Eemulantes . . ." — De Omento et adiposis Ductibus. Opera omnia.
Lond. 1686.
Leeuwenhoek was, however, the first observer who distinctly described the blood
globules in the different classes of animals: this he did in 1673. These historical
reminiscences are not without their interest, and further references of this kind will be
introduced in the course of the work.
* The central depression was first noticed by Dr. Young. The flattened form with
the central depression on each surface, and of which a bi-concave lens would form an
apt illustration, is that which any vesicle partially emptied of its contents would
assume.
f Hewson figured the difference in the form of the blood globule in the embryo,
and in the adult, in the common domestic fowl, and in the viper.
90 ORGANIZED FLUIDS.
these principles is beautifully seen, not merely in the blood globules,
but more especially in those exquisitely delicate formations, the pollen
granules.
■ Between the density of the liquid contained within the red globules,
and that of the liquor sanguinis, in states of health, a nice adaptation
or harmony exists, whereby these globules are enabled to retain their
peculiar form. There is, however, scarcely any other fluid which
can be applied to the globules which does not, more or less, affect their
shape, most of the reagents employed in their examination rendering
them spherical. (See plate I. fig. 3.)
From the preceding observations, therefore, it follows that the red
globules, to be seen in their normal condition, should be examined
while still floating in the serum : they are best obtained by pricking
the finger with a needle or lancet.
Usually, when the microscope is brought to bear upon the object-
glass, the globules are seen to be scattered irregularly over its surface,
the majority of them presenting their entire disc to view, others lying
obliquely, so as to render apparent the central depression, and others
again exhibiting their thin edges, (See Plate I. fig. 1.) Not unfre-
quently, however, a number of corpuscles unite together by their flat
surfaces, so as to form little threads, comparable to strings of beads,
or of coins, which are more or less curved, and in which the lines of
junction between the corpulscles are plainly visible. These strings
of compressed globules bear also a close resemblance to an Oscillatoria,
and a still closer likeness to the plant described in the history of the
British Fresh- water Algae, under the name of Hcematococcus Hooker-
iana. (See Plate I. fig. 4.) The cause which determines this union
of the cells still requires to be explained, and would seem to be referable
to a mutual attraction exerted by the globules on each other. Andral
asserts that when the fibrin of the blood is abstracted, they do not
thus cohere. Professor Nasse, as already remarked, states that this
disposition on the part of the red corpuscles to unite together and form
rolls (as of miniature money in appearance), is increased in inflamma-
tory blood. The union does not, however, last long; a heaving to and
fro of the strings of corpuscles soon taking place, and which terminates
in their disruption.*
* In reptiles, birds, and fishes, the red globules are elliptical, a form possessed also
by some few mammalia, chiefly of the family CamelidcE. This fact was discovered
by Mandl, in the dromedary and paco ; and subsequently by Gulliver, in the vicugna
and llama. The oval globules of these animals, however, could not be confounded
with those of reptiles, buds, and fishes, than the corpuscles of which they are so
THEBLOOD. 91
Size. — The size of the red corpuscles of the blood, although more
uniform than that of the white, is nevertheless subject to considerable
variation. Thus, the globules contained in a single drop of blood are
not all of the same dimensions, but vary much. These variations are,
however, confined within certain limits: the usual measurement in the
human subject is estimated at about the 3 5V0 °f and inch; but, occa-
sionally globules are met with not exceeding the TIj T ; and, again,
others are encountered of the magnitude of the 32V 9 °f an mcn > tnese
are, however, the extreme sizes which present themselves.* The
difference in the size of the red corpuscles, which has been indicated,
is a character common to them in the blood of all persons, and at
every age. Another variation as to size exists, which is, that the
corpuscles are larger in the embryonic and fetal than they are in
adult existence. f This observation is important, inasmuch as it seems
to pi'ove that the blood does not pass directly from the maternal system
into the fetal circulation, but that the corpuscles are formed independ-
ently in the fetus. In states of disease, also, it has been remarked by
Mr. Gulliver that there is even a still greater want of uniformity in
the measurements presented by the red corpuscles.
much smaller, and, further, are destitute of the central nucleus, which characterizes
the blood globules of all the vertebrata,the mammalia alone excepted. The long
diameter of the blood corpuscles of the dromedary, Mr. Gulliver states to be the
s^sx of an inch, and its short the j^y ; the first of these measurements exceeds but
little the diameter of the human blood corpuscles.
Among fishes, one exception to the usual oval form of the blood corpuscle has
been met with: this occurs in the lamprey, the blood disc of which Professor Rudolph
Wagner observed to be circular ; in form then the blood corpuscles of the lamprey
agrees with that of the mammalia, but in the presence of a nucleus, the existence of
which has been recently ascertained by Mr. T. W. Jones, it corresponds with the
structure of the blood discs of other fishes.
* The first measurement given is that which is usually adopted by writers ; the
last two are those made by Mr. Bowerbank for Mr. Owen, and which are to be found
in the latter gentleman's paper on the Comparative Anatomy of the Blood Discs,
inserted in the Lond. Med. Gazette for 1839. The measurements which I have made
of the human blood corpuscle do not accord with those which are generally regarded
as correct : thus I find the average diameter of the blood globule of man to be, when
examined in the serum of the blood, about the -g-gVn °f an inch> an(i m water in which
the corpuscles are smaller, as a necessary consequence of the change of form, the
3^. The micrometer employed by me is a glass one, precisely similar to that
made use of by Mr. Gulliver, being furnished to me by the same eminent optician,
Mr. Ross, from whom his own was obtained.
f This is the opinion of Hewson, Provost, and Gulliver, and I have myself to some
extent confirmed its accuracy.
92 ORGANIZED FLUIDS.
A careful examination of the elaborate tables of Mr. Gulliver on
the measurements of the blood corpuscles, appended to the translation
of Gerber's Minute Anatomy tends to show that a general though not
a very close or uniform relation, exists between the size of the blood
corpuscles among the mammalia, and that of the animal from which
they proceed. These tables furnish more evidence in favour of this
co-relation than they do in support of the assertion that has been made,
that the dimensions of the corpuscle depend upon the nature of the
food. It would appear, however, nevertheless, that the corpuscles of
omnivora are usually larger than those of carnivora, and these, again,
larger than those of herbivora* In a perfectly natural family of
mammalia, as the rodents or the ruminants, there is also an obvious
relation between the size of the corpusucle and that of the animal.
Gerber states that there is an exact relation between the size of the
blood globules and that of the smallest capillaries. This observation
is doubtless strictly correct.
Structure. — Much diversity of opinion has, until recently, prevailed,
and does still obtain, although to a less extent, in reference to the
intimate structure of the red globule. This diversity has arisen partly
from the imperfections of the earlier microscopic instruments employed
in the investigation, and in part is due to the different circumstances
in which observers have examined the blood corpuscle. Thus, one
micrographer would make his observations upon it in one fluid, and
another in some other medium, opposite results and conclusions not
unfrequently being the results of such uncertain proceedings. These
discrepancies it will be the writer's endeavour, as far as possible, to
reconcile with each other, as well as to point out those observations
which are entitled to our implicit belief, and those which yet require
confirmation. This being done, we shall be in a position to form
some certain conclusions. The earlier microscopic observers believed,
almost without exception, in the existence of a nucleus in the centre
of each blood corpuscle. Into this belief they were no doubt led
* The largest globules which have as yet been discovered, are those of the
elephant; the next in size, those of the capybara and rhinoceros; the smallest,
according to the observations of Mr. Gulliver, are those of the napu musk-deer. The
corpuscles of the blood of the goat were formerly considered to be the smallest.
The following are the dimensions given by Mr. Gulliver of some of the animals
above named. Diameter of corpuscle of the elephant, the -^ -$ of an inch ; of capybara
the 32Y3 5 of goat, the -5^; and of napu musk-deer j^^rs- The white corpuscles
of the musk-deer are as large as those of a man; a proof that the red corpuscles are
not formed, as many suppose, out of the colourless blood globules. (See the figs.)
THE BLOOD. 93
more from analogy than from actual observation. Now, analogy,
although frequently useful in the elucidation of obscure points, affords
in the present instance but negative and uncertain evidence. In the
elliptical blood discs of reptiles, birds, and fishes, a solid granular
nucleus does undoubtedly exist; but the best optical instruments, in
the hands of the most skilful recent micrographers, aided by the appli-
cation of a variety of reagents, have failed, utterly, in detecting the
presence of a similar structure in the blood globule of the human
subject in particular, and of mammalia in general. I therefore do not
hesitate to join my opinion to that of those observers who deny the
existence of a nucleus in the blood discs of man and mammalia.*
The appearance of a nucleus is, indeed, occasionally presented;
but this appearance has been wrongly interpreted. An internal small
ring, under favourable circumstances, may be seen in the centre of
each blood corpuscle : this ring is occasioned by the central depression,
the outer margin of which it describes; and it was the observance
of it that gave to Delia Torre the erroneous impression, that each
globule had a central perforation, and therefore was of an annular form ;
and further, probably induced Dr. Martin Barry to describe it as a fibre.
The very existence, on both surfaces of the blood disc, of a deep
central depression, together with its little thickness, almost preclude
the possibility of the presence of a nucleus.
An endeavour to account for the absence of a nucleus in the blood
corpuscle of the human adult has been made by supposing that it does
really exist in the blood of the embryo. The answer to this supposi-
tion is, that no nucleus is to be found in embryonic blood, and that if
it were, it would be no reason why the nucleus should not also be
met with in the blood of the adult, seeing that the blood disc is not a
permanent structure, as an eye or a limb, but one which is perpetually
subject to destruction and renewal.
Having then arrived at the conclusion that no nucleus exists in
the blood corpuscle of man, we have now to ask ourselves the ques-
tion, what, then, is really the constitution of the red blood globule?
Some observers have compared it to a vesicle. This definition
does not seem to be altogether satisfactory; for although each
corpuscle possesses the endosmotic properties common to a vesicle,
* Among those who have asserted their belief in the presence of a nucleus, may-
be mentioned Hewson, Miiller, Gerber, Mandl, Barry, Wagner, Rees, Lane, and
Addison ; and of those who have held a contrary opinion, Magendie, Hodgkin, Liston,
Young, Quekett, Gulliver, Lambotte, Owen, and Donne.
94 ORGANIZED FLUIDS.
no membrane, apart from the general substance of the globule, (I
speak more particularly of the human blood disc,) has been demon-
strated as belonsinar to it.
Each globule in man may therefore be defined to be an organism
of a definite form and homogeneous structure, composed chiefly of the
proteine compound globuline, which resembles albumen very closely
in its properties ; its substance externally being more dense than
internally, it being endowed with great plastic properties, and, finally,
being the seat of the colouring matter of the blood.
The extent to which the red globule is capable of altering its form,
is truly remarkable. If it be observed during circulation, it will
be seen to undergo an endless variety of shapes, by which it
accommodates itself to the space through which it has to traverse,
and to the pressure of the surrounding globules. The form thus
impressed upon it is not, however, permanent; for as soon as the
pressure is removed, it again instantaneously resumes its normal
proportions. On the field of the microscope, however, the corpuscles
may be so far put out of form, as to be incapable of restoration to
their original shape.
Some observers have assigned to the red globule a compound
cellular structure, comparing it to a mulberry. It need scarcely be
said that such a structure does not really belong to it. A puckered
or irregular outline is not unfrequently presented by many globules;
this is due sometimes to evaporation, and then arises from the presence
around the margin of the disc, and occasionally over the whole
surface, of minute bubbles of air;* and at other times it is the result
of commencing decomposition, or the application of some special
reagent, as a solution of salt, in which cases a true change in the form,
but not in the structure of the globule, does really occur; its outline
becomes irregular, and the surface presents numerous short and obtuse
points or spines.f Globules in this state bear some resemblance to the
pollen granules of the order Compositce.X (See Plate I- fig. 5.)
* This vesiculated appearance of the blood corpuscles may be produced at once
by pressure.
f Mr. Wharton Jones says, " the granulated appearance " seems to be owing to a
contraction of the inner and a wrinkling of the outer of the two layers of wnich he
conceives the wall of the corpuscle to be formed.
I The opinions promulgated by some observers in reference to the intimate struc-
ture of the blood corpuscles are singular, and are rendered interesting mainly by
reason of the ingenuity of the views expressed. Mr. Addison remarks:1 "Blood
1 Experimental Researches, pp. 236, 237. Transactions of Prov. Med. and Surg. Association.
THEBLOOD. 95
Colour. — The hcematine, or colouring matter of the blood, seems
in the red corpuscle of the mammalia to be diffused generally
throughout its substance; in the oviparous vertebrata, however, it is
confined to that portion of each corpuscle which corresponds with
corpuscles, therefore, appear to consist of two elastic vesicles, one within the other,
and to possess the following structure: 1st, an external and highly-elastic tunic,
forming the outer vesicle; 2d, an inner elastic tunic, forming the interior vesicle;
3d, a coloured matter, occupying the space between the two tunics; and 4th,
a peculiar matter, forming the central portion of the corpuscle." Mr. Wharton
Jones l ascribes a somewhat similar constitution to the blood corpuscle : " The thick
wall of red corpuscle," he says, "consists of two layers. The outer is transparent,
colourless, structureless, and resisting, and constitutes about one-half of the whole
thickness of the wall. The inner layer is softer and less resisting; and is that
which is the seat of the colouring matter." Dr. G. O. Rees and Mr. Lane 2 describe
the blood corpules as containing a fluid, and provided with a nucleus composed of a
thin and colourless substance. The views of Dr. Martin Barry are, however, the
most peculiar of any ever yet published in reference to the blood corpuscle; when first
they were announced in the pages of the Philosophical Transactions, the scientific
world were taken by surprise and wonderment. Microscopes, which had long been
suffered to remain undisturbed on their shelves, were immediately had recourse to,
and many scientific men, who previously had never employed the instrument in their
investigations, were induced to procure it, in order that they might themselves bear
ocular witness of the astonishing facts related by Dr. Barry in reference to blood
corpuscles. A short abstract of Dr. Barry's views will be read by some with interest.
Dr. Barry considers that the molecules, the red corpuscles, and the white globules,
are different states of the development of the same structure, the true blood globule.
(This is also the opinion of Addison and Donne.) The first he denominates a
"disc," and the last a "parent cell." These different stages in the development of the
blood globule, Dr. Barry compares with similar conditions of the germinal vesicle of
the ovum. "The disc," he says, "is the most primitive object we are acquainted
with;" that it is synonymous with the "nucleus" of most authors, and the "basin-
shaped granules" of Vogel ; that it " contains a cavity, or depression," " the nucleo-
lus," which " is the situation of the future orifice," which he says the blood corpuscle
in certain states exhibits, and "by means of which there is a communication between
the exterior of the corpuscle and the cavity in its nucleus ;" lastly, the disc is
regenerated by fissiparous divisions. These discs are also denominated, " primitive
discs," "foundations of future cells." The "parent cells" he conceives to be made
up of an assemblage of these discs. Again, Dr. Barry states, " The nuclei of the
blood corpuscles furnish themselves with cilia, revolve, and perform locomotion;"
"the primitive discs exhibit an inherent contractile power." And of the corpuscles
themselves, he remarks, " Molecular motions are discernible within the corpuscles of
the blood," — " changes of form are observed under peculiar circumstances in the
corpuscles of the blood." These are, however, only the beginning of wonders related.
Dr. Barry elsewhere goes on to observe : " In the mature blood corpuscle (red blood
1 See British and Foreign Medical Review, No. xxvni. 2 Guy's Hospital Reports, 1840.
96 OEGAN1ZED FLUIDS.
the blood disc of the mammiferous vertebrata, viz: the outer or
capsular portion of it — the nucleus which alone exists in the blood
corpuscles of birds, fishes, and reptiles, being entirely destitute of
colouring matter.
The colour of the blood, it has long been believed, is intimately
disc), there is often to be seen a flat filament or band already formed within the
corpuscle. In Mammalia, including man, this filament is frequently annular; some-
times the ring is divided at a certain part, and sometimes one extremity over-laps the
other. In birds and amphibia the filament is of such length as to be coiled. This
filament is formed of the discs contained within the blood corpuscle. . . "The fila-
ment thus formed within the blood corpuscle has a structure which is very remarka-
ble. It is not only flat, but deeply grooved on both surfaces," in an oblique manner.
"It is deserving of notice," continues Dr. Barry, "that in the first place, portions of
coagulum of blood sometimes consist of filaments having a structure identical with
that of the filaments formed within the blood corpuscle; secondly, that in the coagu-
lum I have noticed the ring formed in the blood corpuscle of man, and the coil formed
in that of birds and reptiles, unwinding themselves into the straight and often parallel
filaments of the coagulum, changes which may be seen also taking place in blood
placed under the microscope before coagulation; thirdly, that I have noticed similar
coils strewn through the field of view when examining various tissues, the coils here
also appearing to be altered blood corpuscles and unwinding; lastly, that filaments
having the same structure as the foregoing, are to be met with apparently in every
tissue of the body." These filaments Dr. Barry conceives finally to constitute "fibre,"
whenever this elementary structure is encountered.
These multiplied and extraordinary observations of Dr. Barry, it is now necessary
to observe, remain unconfirmed in all the most essential particulars up to the present
time. Shortly after their promulgation, Dr. Griffiths,1 and Mr. Wharton Jones,2
objected to the statement of Dr. Barry, that there exists in the blood corpuscle a pri-
mordial fibre, observing that the appearances relied upon were due to decomposition.
In connexion with the subject of fibre in the blood globules, the analogy referred to
by Dr. Willshire, 3 between a dark line observed in the starch vesicle, and Dr. Barry's
alleged fibre, may be noticed, as well as the affirmations of Dr. Carpenter, 4 that Dr.
Barry had shown him, among corpuscles of the blood of the newt, preserved in its
own serum, many of a flask-like figure, and which might be compared to a pair of
bellows, and the projecting portion of which appeared to Dr. Carpenter to be a fila-
ment having a much higher refracting power than the general substance of the cor-
puscle. Dr. Barry also showed Dr. Carpenter, in blood preserved in corrosive sublimate,
a corpuscle which was evidently destitute of the ordinary nucleus, and which contained
what appeared to be a filament, presenting transverse oblique markings which
resembled those of the fibrillfe of a muscle. The observations of Dr. Barry, and the
confirmatory statements of Dr. Carpenter, will at least be possessed of historical
interest, if any real and intrinsic importance be denied to them. The views of Dr.
Barry are given at length in the Philosophical Transactions for 1840 — 1843.
l Annals of Natural History February, 1843. 2 Transactions of the Royal Society, December, 1842.
3 Annals of Natural History, 1843. 4 Annals of Natural History, 1842.
THE BLOOD. 97
connected with the presence of iron in the blood corpuscles : from the
fact, however, that iron exists in the chyle,* and in the colourless
blood of certain animals,f it is clear that the mere presence of iron is not
in itself sufficient to account for the colour of the blood ; this depends
most probably upon the state of combination of the iron in the blood.
Liebig states, as will be shown immediately, that the iron in the
blood exists in the varying conditions of peroxide, protoxide, and
corbonate of the protoxide of iron.
USES OF THE RED CORPUSCLES.
In connexion with Respiration. — Observation has taught us the
fact that the colour of the blood changes considerably, according as it is
exposed to the influence of oxygen and carbonic acid gases ; it becom-
ing bright red under the influence of the former, and dark red, almost
black, under that of the latter gas.
Now, the microscope has revealed to us the additional fact that the
colouring matter of the blood resides within the red corpuscles ; and
hence we are led to infer that the changes of colour alluded to are
accompanied by alterations in the condition of the colouring matter
contained in those corpuscles.
Further, the alterations of colour which have been mentioned take
place not only in blood withdrawn from the system, but also in that
which still circulates in the living body, the vital fluid being exposed
in the lungs to the influence of the oxygen contained in the atmosphere,
and to carbonic acid in the capillary system of vessels.
But it is not merely a change of colour which the blood undergoes,
or rather the coloured blood corpuscles undergo, on exposure to either
of the gases particularized, but they also experience at the same time,
as might easily be inferred, a positive change of condition, a portion
of one or other of the gases to which the blood corpuscles are exposed
being imbibed by them.
That it is really the red corpuscles which absorb the oxygen, or the
carbonic acid, as the case may be, admits of demonstration, and is
proved by the fact that these gases lose but little volume when placed
in contact with the liquor sanguinis, or serum of the blood.
* See article " Lymphatic System," by Mr. Lane. Encyclopardia of Anatomy and
Physiology, April, 1841.
f "The Blood Corpuscle considered in its different Phases of Development in the
Animal Series," by J. W. Jones, F. R. S. Transactions of the Royal Society, part ii.
for 1846.
7
98 ORGANIZED FLUIDS.
It is clear, then, that the coloured corpuscles are the seat in which
these changes occur. Again, from the fact that the blood becomes
bright red or arterial on exposure to oxygen, as in the lungs, and dark
red or venous on being submitted to the action of carbonic acid, as in
the capillaries, it has been inferred that they are, first, carriers of
oxygen from the lungs to all parts of the system, and, second, vehicles
for the conveyance of carbon back again to the lungs.
This inference is correct as far as it goes, but it fails to explain
why the imbibition of oxygen or carbonic acid gases should be
accompanied by changes in the colour of the blood ; and it also fails
to show why those gases themselves should be imbibed.
From the constant presence of iron in the coloured blood corpuscles,
it has been inferred that this is the base with which the oxygen and the
carbonic acid gases combine, but the exact nature of the combi-
nations thus formed it was reserved for the illustrious Liebig to make
known.
Liebig declares that, in arterial blood, the iron is in the state of a
peroxide, and in venous blood in the condition of a carbonate of the
protoxide.
To this conclusion Liebig has arrived by observing the manner in
which the above-mentioned compounds of iron comport themselves
when not in connexion with the blood, but when exposed to the same
influences as the blood itself is subjected to.
Thus, he says, " The compounds of the protoxide of iron possess the
property of depriving other oxydised compounds of oxygen, while the
compounds of peroxide of iron under other circumstances give up
oxygen with the greatest facility."
Again, " Hydrated peroxide of iron, in contact with organic matters
destitute of sulphur, is converted into carbonate of the protoxide."
Lastly, "Carbonate of protoxide of iron in contact with water and
oxygen is decomposed, all the carbonic acid is given off, and by
absorption of oxygen it passes into the hydrated peroxide, and which
may again be converted into a compound of the protoxide."
Now, the above-described changes, which the compounds of iron
when exposed to the same influences as the blood corpuscles are
themselves submitted to, precisely correspond with those alterations
which it is known and ascertained that the blood corpuscles do them-
selves experience, and therefore there is every probability in favour of the
strict accuracy of Liebig's explanation of the chemical changes which
the blood corpuscles pass through during respiration and circulation.
THE BLOOD. 99
Thus, it has been long known, that in the lungs the coloured blood
corpuscles give off carbonic acid, and imbibe oxygen: and it has also
been ascertained that during their circulation they lose a portion of
their oxygen, and acquire carbon.
Venous blood, then, exposed to the air, gives out carbonic acid, and
absorbs oxygen; but arterial blood, submitted to the same influence,
gives out oxygen, and acquires carbonic acid; the seat of these changes
being the red corpuscles.
It will be seen, on reflection, that, according to the views just pro-
pounded, the surplus amount of oxygen which exists in the peroxide,
becomes disengaged in the reduction of that oxide to the state of
protoxide: during circulation in the capillaries, this surplus is chiefly
expended in the elaboration of the different secretions which are
continually being formed in the various organs of the body.
Such is the corpuscular theory of respiration. Hereafter we shall
have to speak of a corpuscular theory of nutrition, growth, and
secretion.
In connexion with Secretion. — It is very probable that the use of
the red corpuscles is not limited to the mere office of carrying oxygen
from the lungs to be distributed to all parts of the system, and of carbon
back again to the lungs to be eliminated, but that they have an ulterior
and additional function to discharge. Thus, some observers suppose
that they exert some influence over the constitution of the blood itself,
elaborating, from the materials continually thrown into it by the tho^
racic duct, a further quantity of fibrin. There is more reason to believe,
however, that it is the white corpuscles which are principally concerned
in this process of elaboration, seeing that their structure agrees with
that which is generally possessed by true secreting cells. I therefore
myself would be inclined to attribute to the red corpuscles but little
influence over the constitution of the blood.
It may be stated that both Wagner* and Henle are of opinion that
the red corpuscles are connected with secretion, and the latter, in his
"General Anatomy," calls them " swimming glandular cells."
Effects of Reagents.
The blood globules are much modified by tne application of numer-
ous reagents, and which, therefore, may be employed with advantage
in their investigation.
* Physiology, by Willis, part ii. p. 448.
100 ORGANIZED FLUIDS.
Serum. — It has already been observed that, in the serum of the
blood, their natural element, the globules preserve unaltered, for a
time, their normal form.
Water. — The application of water causes the globules almost
immediately to lose their flattened and discoidal character, the depres-
sions on their surface are effaced, and they become spherical. This
change in the form of the corpuscles is necessarily accompanied by a
diminution of their size. (See Plate I. jig. 3.)
Spirits of Wine, JEther, Creosote. — The same results follow the
use of a variety of liquids, as spirits of wine, aether and creosote.
These agents, however, in addition, render the globules exceedingly
diaphanous, so much so indeed as that they are often with difficulty
to be discovered. In the globules rendered thus transparent, no traces
of granular contents can be detected.
Acetic acid. — This preparation first deprives the globules of their
colouring matter, thus rendering them exceedingly transparent, and
subsequently dissolves the human blood corpuscle, without residue,
but not that of a frog, &c, the nucleus of which remains entire.
(See Plate II. fig. 5.)
Ammonia. — This alkali acts in a similar manner.
Nitric Acid, Muriate of Soda. — These reagents contract the
globules, and render their outline more distinct.
Iodine. — This likewise renders the outlines more distinct, without
at the same time deforming and otherwise altering the globules.
Corrosive Sublimate. — In a strong solution of this liquid, the outlines
of the globules are more defined, and the globules may be preserved
for examination for a considerable length of time.
We shall next pass to the consideration of the white globules, and
show in what particulars of form and structure they differ from the red.
WHITE GLOBULES.
The white globules of the blood are by far less numerous than the
red; they nevertheless are more abundant than a superficial observer
would suppose : this arises from the fact that many of them are con-
cealed from view on the field of the microscope by the red globules,
which so greatly outnumber them. The white corpuscles differ from
the red in several particulars : in size, in colour, in form, in structure,
in their properties, and doubtless also in their uses.*
* Spallanzani was the first to notice the existence of two forms of globules in the
blood of salamanders; Miiller verified their presence in that of the frog, and M. Mandl
detected them in man and mammalia.
THE BLOOD. 101
Size. — In man and the mammalia the white globules are generally-
larger than the red : like those, also, their dimensions vary very con-
siderably in the blood of the same individual abstracted at any given
time, and even to an extent still greater. Their average size, when
contained in the serum of the blood, may, however, be estimated at
about the ^jVo °f an inch* (see Plate I. fig. 1) : when immersed in
water, however, they swell up, and increase very considerably in size,
in this liquid sometimes measuring the TJ~ of an inch. (See Plate I.
fig. 6.) In the blood of reptiles, especially in that of the frog, a
contrary relation between the size of the red and white globules exists ;
the latter in these, instead of being larger than the red corpuscles,
are two or even three times smaller. This fact it is important to bear
in mind, in considering the question of the transformation of the white
globules into red.
Form. — Instead of being of a flattened and disc-like form, as are
the red globules, the shape of the white corpuscle, when free, is in all
classes of the animal kingdom globular. This particular likewise
throws much light upon the disputed point as to whether the white
globules become ultimately converted into red corpuscles, and which
we shall have to treat of more fully hereafter.
Like the red corpuscles, however, although to a less remarkable
extent, the white globules, when subject to pressure, undergo a change
of form : this change is frequently well seen when viewing the circu-
lation of the blood in the capillaries, the white corpuscles often becom-
ing compressed between the walls of the vessels and the current of
red blood discs, and by which compression they are made to assume
elongated and oval forms ; like the red corpuscles, also, they immedi-
ately regain their normal form, the pressure being removed.
Structure. — In almost every relation which can be named, the
white globules would appear to be the antagonists of the red; for,
instead of being of a homogeneous texture, they are of a granular
structure throughout, each full-sized white globule being constituted
of not less than from twenty to thirty distinct granules, the presence
of which imparts to it a somewhat broken outline: these granules
are often seen, especially after the addition of water, and some other
reagents, to be in a state of the greatest activity in the interior of the
corpuscles. It is only in the blood globule of mammalia, however,
that we find this antagonism to prevail. The blood corpuscle of the
* Mr. Gulliver gives the 2T0 „- °f an inen as the average measurement of the human
colourless blood corpuscle.
102 ORGANIZED FLUIDS.
frog, and doubtless of other reptiles, as well as birds and fishes, is
assuredly a compound structure, the investing or transparent part of
each being in no way, as regards structure, distinguishable from the
substance of the human blood disc, and the nucleus also being iden-
tical in composition, though not in origin, with the white globules of
the blood, not merely of mammalia, but likewise of reptiles, birds,
and fishes. (See Plate II. fig. 5.) The form of the nucleus, in the
frog, &c, corresponds with that of the globule; that is, it is elliptical
(see Plate II. fig. 2) : water, however, affects the nucleus, as first
observed by Mandl, in the same way as it acts upon the corpuscle
itself, rendering both perfectly spherical. (See Plate W.figs. 3 and 4.)
If to globules in this condition acetic acid be added, the capsule will
be dissolved, leaving intact the nucleus, between which and a white
globule I have not been able to detect, although using an instrument
of the very best description, the slghtest structural difference: a dif-
ference does certainly exist, but it is one of size, and not of structure,
the nucleus being three or four times smaller than a white globule of
ordinary dimensions. (See Plate 11. fig. 5, and Plate II. fig. 1.)
This identity of organization between the white globule and the
nucleus of the blood disc of the frog, furnishes the strongest evidence
with which I am acquainted of the convertibility of the white glob-
ules into red, evidence which, nevertheless, I regard as wholly inade-
quate to demonstrate the reality of the conversion.
Nucleus. — The white corpuscles, under some circumstances, would
appear to be nucleated ; thus nuclei are evident in corpuscles which
have been immersed in water, or even in serum, for any length of
time, although they are not usually seen in those of that fluid imme-
diately after its abstraction from the system. I am inclined to regard
their formation as resulting partly from the operation of endosmosis,
whereby a portion of the contents of each corpuscle becomes con-
densed in the centre.
The nucleus occupies sometimes the entire of the interior of the
corpuscle, a narrow and colourless border destitute of granules, alone
indicating the extent of the corpuscle; generally, however, it is about
the one-third of its size, and is more frequently eccentric than centric.
It is usually darker than the rest of the corpuscle, and would appear
to contain a greater number of molecules. (See Plate I. fig. 6.)
Sometimes it presents to the eye of the observer the appearance of
an aperture; this appearance, although very striking, is most probably
fallacious.
THE BLOOD. 103
Mr. Addison regards the nucleus presented by the white corpuscles
as primary, an opinion in which I concur.
Properties. — The white corpuscles of the blood differ not less in
their properties from the red than they do in form and structure:
thus, acetic acid, which dissolves the latter, contracts somewhat the
former, and renders the contained granules more distinct; in water,
the red globules become globular and smaller in size, while the white
increase considerably in dimensions in the same liquid (see Plate I.
fig. 6), and finally burst in it, their molecular contents escaping. In
liquor potasses, both the red and white corpuscles are destroyed and
dissolved ; previous to which, however, in the white globules, some
interesting changes are seen to take place ; immediately on the appli-
cation of the alkali, the molecules contained in their interior are
observed to be in active motion, and in a short time the corpuscles
burst open, or explode, discharging numerous granules, amounting
sometimes to thirty or forty; and which, together with the transpa-
rent matter of the corpuscles, finally becomes dissolved. — "Frequently,
when the liquor potassee is acting with diminished energy, the cor-»
puscles give a sudden jerk, and in a moment enlarge to double or
three times their former size, without losing their circular outline:
the molecules and granules within them are more widely separated
from each other, but not dispersed; and they are seen held together,
or attached to the tunic of the corpuscle, by delicate connecting fila-
ments. This singular and instructive change does not, of course,
last long; the alkali, continuing its action, ruptures the tunic of the
corpuscle, dispersing and dissolving its contents." — Addison.
When examined in the living capillary vessels, they are seen to
manifest different properties to the red, and also to have a very different
distribution in those vessels. Thus, the white corpuscles frequently
adhere to the inner wall of the capillaries, which the red rarely do ;
and while the red globules, in circulating, occupy the centre of each
vessel, the white corpuscles are placed between this and the walls of
the vessel.
A difference may also be observed in the relative speed with which
the two kinds of corpuscles circulate, the red flowing onwards with
greater rapidity than the white. The forces which determine the
circulation in the vessels would appear to act only on the red cor-
puscles, the motion of the white globules being entirely of a secondary
and indirect character, it being communicated to them by the edge
of the current in the axis of which the red corpuscles move, in the
104 OEGANIZED FLUIDS.
same way as the stones at the bottom of a stream are rolled over and
borne onwards by the superincumbent water.
The cause of the slower motion of the white corpuscles in the
capillaries may be thus explained. A greatly retarded motion of the
fluid circulating in any vessel or channel is always observed towards
the periphral border of the current. This retardation would appear
to arise from the resistance which the circulating fluid encounters
by coming in contact with the walls of the vessel or sides of the
channel through which it flows.
In what way, however, is the difference in the position in the ves-
sels occupied by the red and white corpuscles to be explained? whv
do the former always circulate in the axis of the vessel, while the
latter are constantly placed outside this ? and what is the inference to
be deduced from this difference in their situation ?
The red corpuscles, as we know, are flattened discs, constituted of
an elastic and yielding material; and the white, on the contrary, are
globular bodies of a more dense composition and of but little elasticity.
*Now, it is very probable that the peculiar form and properties pos-
sessed by the coloured corpuscles of the blood may result in such an
adaptation and arrangement of them, the one with the other, that a
physical impossibility is presented to their indiscriminate admixture
and circulation in the same vessel with the white corpuscles.
But there are other facts which will serve to explain the difference
of position: Thus, the red corpuscles have an attraction for each
other, as is manifested on the field of the microscope by the formation
of the strings of corpuscles already referred to, where also it is seen
that they have no such affinity for the white corpuscles, which
usually lie detached and isolated from the red. On the other hand,
however, the white, as before stated, have an attraction for the walls
of the vessels through which they pass, and which is declared by
their frequent adhesion thereto.
The question may be asked, have these attractions any thing to do
with electric conditions? All the inquiries which have been under-
taken, with the view of proving that the blood is possessed of electric
properties, have hitherto signally failed to demonstrate the existence
of any.
Lastly, what inference is to be deduced from the different positions
occupied by the two kinds of blood corpuscles, and from the different
rates of their circulation in the capillaries ?
The rapid passage of the red corpuscles through the capillaries,
THE BLOOD. 105
together with their central situation, would lead the observer to infer
that they had but little direct relation with the parts outside those
capillaries; that the office discharged by them was one of distribu-
tion ; whereas the slow progress of the white corpuscles through the
capillary vessels, as well as their peripheral position, would lead to
the conclusion that a close relation existed between them and the
parts adjacent and external to the vessels. Now, these deductions
are precisely those which other facts and observations tend to con-
firm and establish, as we have already seen in reference to the red
corpuscles, and as we shall immediately proceed to show in relation
to the white globules.
While viewing the capillary circulation, it is easy to convince
oneself that no contraction of the parietes of the capillaries occurs,
and that, therefore, the motion of the blood is independent of any
action of those vessels themselves, on their contents.
USES OF THE WHITE CORPUSCLES.
The uses of the white corpuscles have not as yet oeen fully deter-
mined; enough, however, of their nature has been ascertained to
show that they are closely connected with the functions of Nutrition
and Secretion. We shall here invert the natural order in which the
description of these subjects should be entered upon, and speak first
of secretion.
Uses in connexion with Secretion. — It would appear that, for the
most part, secretions are formed in cells : the correctness of this
statement is, in some degree, proved by the fact that the lower classes
of the vegetable kingdom are entirely constituted of cellular tissue.
It is also further supported by the fact, that the essential structure
of all glands in the animal frame is that of cells.
It would appear, also, that the cells, entering into the composition
of a single organ, have the power of producing more than one kind
of secretion. This is witnessed in the petals of many flowers, the
cells of which frequently elaborate fluids of several distinct colours.
There is much reason to believe, that the granules, which are so
constantly associated with the cells, are the active agents engaged in
the production of the secretion, the exact constitution of these granules
determining the character of the secreted product.
Now, in the white corpuscles of the blood we have precisely the
same granular constitution which is seen to belong to cells which are
indisputably engaged in the process of secretion.
106 ORGANIZED FLUIDS.
From the observation of these and other facts, Mr. Addison has
been led to entertain the opinion, that the white corpuscles of the
blood "are very highly organized cells, from which the special tissues
and the secretions are elaborated."* In continuation of this subject,
Mr. Addison goes on to remark : "And it appears that the renovation
of these tissues and secretions from the blood does not take place by
the cells discharging their contents into the general mass of the
circulating current, to be separated therefrom by some peculiar
transcendental and purely hypothetical selective process of exudation,
through a structureless and transparent tissue, but by being them-
selves attached to, incorporated with, and performing their special
function in the structure."
Thus, Mr. Addison conceives that the fibrillating liquor sanguinis
is formed and elaborated in the white corpuscles of the blood, and
that it never exists in that fluid in a free state, and that its presence
in the crassamentum, and especially in that part of it which consti-
tutes the buffy coat, arises from the rupture and destruction of the
white corpuscles, and the escape of their contents. This opinion he
supports by a series of ingenious experiments, one of which may here
be referred to. The tenacious property belonging to mucus is well
known, in which respect, as well as in the smaller number of globules,
similar to the white corpuscles of the blood contained in it, it differs
mainly from pus. Now, by the addition of a drop of liquor potasses
to a little pus, which was previously white and opaque, and in which
the presence of a considerable number of white corpuscles was
ascertained by means of the microscope, its appearance underwent a
complete change, the pus became transparent and tenacious, presenting
precisely the characters of mucus. The fluid being again examined
microscopically, it was found that most of the globules were ruptured
and dissolved, and that the liquid portion of it fibrillated in the same
way as that of mucus, and that of the liquor sanguinis ; from this
and other analogous experiments Mr. Addison formed the conclusion,
that the fibrillating liquor sanguinis was derived from the white
corpuscles, and that it does not exist in the blood in a free condition.
According to Mr. Addison, the secretions, "milk, mucus, and bile,
are the visible fluid results of the final dissolution of the cells."
Hence, therefore, a secretion is the result of the last stage of the
process of nutrition. And, again, "If, therefore, the colourless blood
* "Experimental Researches," Transactions of Prox. Med. and Surg. Association,
vol. xii. p. 260
THE BLOOD. 107
corpuscles be termed "parent cells," they must be considered as
pregnant with the embryo materials of the tissues and secretions, and
not with "young blood cells."
It is scarcely necessary to observe that these highly ingenious
views of Mr. Addison are by no means established. That the cells
of glands and their contained granules are intimately connected with
secretion, there are many facts to prove ; but that the white corpus-
cles of the blood are, in the animal economy, the special organs of
secretion, and also that the secretions said to be elaborated by them,
escape from them, not by transudation through their membranes, but
are set free by the entire and final dissolution of the corpuscles, are
views which cannot be safely adopted until much additional evidence
is adduced in support of them.
The opinion entertained by Dr. Barry, that the colourless corpuscles
are "parent cells," seems to me to be purely hypothetical.
Let us now bestow a few reflections upon Nutrition :
Uses in connexion with Nutrition. — That the white corpuscles are
concerned in the process of nutrition, there is more evidence to show
than there is in favour of their connexion with that of secretion. The
question to be solved, however, is, in what way do these corpuscles
administer to nutrition ? do they contribute to nutrition and growth,
by their direct apposition to and incorporation with the different
tissues of organs? This is the opinion of Mr. Addison, who says of
them, that they are the "foundations of the tissues and the special
secreting cells, the link between the blood and the more solid struc-
tures, the unity from which the pluralities arise."
Dr. Martin Barry also adopts the notion that tissues are formed by
the direct apposition of the blood corpuscles. Dr. Barry makes no
exact distinction between the red and the colourless globules; but
from the fact of his calling the latter "parent cells" filled with "young
blood discs," it would appear that he considered that the red corpuscles
gave origin to the different structures of the body by their direct union
and incorporation with each other. This view is far less tenable than
that of Mr. Addison, and neither is supported by a sufficient number
of facts to render its accuracy any thing but exceedingly problematical.
That the white corpuscles of the blood are engaged in the process
of nutrition is proved by the fact, that they are found in increased
quantities in vessels which are actively administering to that function.
This accumulation is witnessed also in the capillary vessels of any
parts which are subjected to irritation of any sort, and in which, as a
consequence of that irritation, there is augmented action.
108 ORGANIZED FLUIDS.
The gradual collection of the white corpuscles of the blood in the
capillary vascular net-work, may be seen to the greatest possible
advantage in the tongue of the frog, as also in the web of the foot of
that coveniently-formed creature, as the result of continued exposure
of the parts to the action of air.*
But it is not alone the aggregation of the colourless corpuscles that
may be seen in the minute vessels ; their escape from those vessels
may likewise be determined by a prolonged examination of them. If,
after the continuance of this congested condition of the vessels for
twenty-four or thirty-six hours, they are again examined, it will be
obvious that certain of the corpuscles have become entangled in the
fibres which form the walls of the vessels, and that certain others
have altogether passed the boundaries of the vessels, and now lie
external to them.
Again, it is asserted, that the epithelial cells are derived from the
white corpuscles of the blood. If this be correct, it would appear
that the escape of these corpuscles is a perfectly normal and natural
occurrence.
Thus far, then, the endeavour to prove the transformation of the
colourless corpuscles of the blood into tissue cells, would appear to be
successful; but it is here the chain of evidence breaks; and beyond
the fact, which is by no means established, of their constituting
epithelial cells, we have no further proof to adduce of their structural
incorporation with the living tissues. Of this occurrence it would, of
course, be difficult to procure satisfactory demonstration, on account
of the opacity of the parts on which our examination would have to
be conducted. It may be remarked, however, that, if founded in fact,
we should expect to find a greater correspondence in the size and
form, &c, of the elementary tissues, with that of the corpuscles from
which, according to some observers, those tissues are derived. f
The corpuscular theory of nutrition, then, proposed by Mr. Addison,
* Mr. Addison states that, in order to insure a satisfactory exhibition of this
important and curious phenomenon, the parts should be irritated in some manner, as
by immersion for a minute or two in warm water at a temperature of 95° Fahrenheit,
or by permitting a few. crystals of common salt to dissolve upon it. These
methods I have tried, and have found that they have usually resulted in the entire
cessation of the circulation in the capillaries, and this has been also the case even
when a weak solution of salt in water has been applied.
f The cells of the liver and spleen resemble closely in appearance the white cor-
puscles of the blood ; between them, however, well-marked differences exist, so that
it is by no means to be inferred that the former are derived directly from the latter.
THE BLOOD. 109
in the present state of our knowledge, can only be sustained by having
recourse to a certain amount of theoretical reasoning or to particular
assumptions.
The fact, however, still remains to us, that the white corpuscles
are concerned in nutrition, although the precise manner in which they
are so is still open to investigation, and this fact is strengthened and
confirmed by the phenomena of disease. Thus, there is much
evidence to show that, wherever nutrition is impeded, the colourless
corpuscles accumulate in increased quantities in the vessels; and it is
by this accumulation, also, that we are enabled to account for the
critical abscesses and discharges which characterize some affections,
and to recognise the importance which ought to be attached to their
occurrence.
That the colourless corpuscles are really present in increased
numbers in the blood, in disease, is attested by the evidence of numer-
ous observers: thus, Gulliver,* Davy,f and Ancell,J have observed
them in unusual quantities in inflammatory affections, and especially
in such as are attended with suppuration. Mr. Siddall and Mr.
Gulliver have repeatedly observed them in vast numbers in the horse,
especially when the animal has been suffering from influenza. Donne
has likewise recognised their presence in increased quantities in
disease; and Mr. Addison finds them to abound in the hard and red
bases of boils and pimples, and in the skin in scarlatina and in most
cutaneous affections.
Several processes may have been pointed out by which the white
globules may be separated from the red, and thus be brought in a
manner more satisfactory under view. 1st. Acetic acid dissolves the
red corpuscles, leaving the white almost unchanged. 2d. A drop of
water, floated gently across a piecs of glass, on which a small quantity
of blood has been placed, will remove the red corpuscles, the white
remaining adherent to the surface of the glass. This ingenious method
was, I believe, first indicated by Mandl. 3d. The third process
depends for its success upon the defibrination of the blood by whipping,
and which has already been alluded to. If blood thus defibrinated be
set aside for a time, the red globules will subside to the bottom of the
containing vessel, forming one stratum, and the serum will float upon
the top, constituting a second layer ; but between these two layers a
* Appendix to Gerber's General Anatomy, p. 20.
f Researches, Phys. and Anal., vol. ii. p. 212.
I Lectures in the Lancet, 1839-40, vol. ii. p. 777.
HO ORGANIZED FLUIDS.
third exists; this is very thin, and is formed by the white globules,
which may be reached after the removal of the serum by means of a
siphon.* Donne points out this method in his excellent "Cours de
Microscopic" 4th. A fourth means of procuring the white globules
is described by Mr. Addison. If a portion of fluid fibrin be removed
from beneath the pellicle which is first formed over the clot, it will be
found to contain numerous white globules.
The observer, having satisfied himself of the accuracy of the various
facts brought under his notice, in the next place will be prepared to
enter into the important questions as to the origin and destination of
the globules of the blood. We will consider first the origin of the
white globules.
ORIGIN OF THE GLOBULES OF THE BLOOD.
The origin and end of the blood globules ! Whence do they come,
and whither do they go ? These are questions of the highest import-
ance ; and it could be wished that the replies to them were of a more
satisfactory and definite nature than those which we are about to
make will, it is feared, be considered.
Origin of the White Globules. — Various opinions have been enter-
tained in reference to the nature and origin of the white corpuscles
of the blood, the principal of which we will now proceed to notice.
One of the earliest notions formed respecting the white corpuscles
was that of Hewson, who believed that they were to be considered as
the nuclei of the red blood corpuscles, and hence he denominated them
"central particles:" to this conclusion Hewson was doubtless led by
observing the great and remarkable resemblance which exists between
the nuclei of the blood globules of certain animals and the white
corpuscles themselves.
Two facts, however, are known, which satisfactorily prove that the
denomination of central particles is not applicable to the white cor-
puscles, and that they do not form the nuclei of the red blood discs;
the first of these is, that no nuclei exist in the true blood globules of
the entire class of mammalia in which white corpuscles are abundantly
encountered, and the second is the great difference in size observed
* The position occupied in this case by the white corpuscles shows that they are
of lighter specific gravity than the red, a reference to which fact will also account for
their presence, in such quantities, in the bufiy coat of the blood, and will likewise
explain the reason why they first come into focus when mixed with the red globules
in a drop of water.
THE BLOOD. Ill
between the nuclei and the white corpuscles in those animals in which
the two organisms exist together in the blood.
An opinion somewhat similar to the above has been held by some
observers, viz: that the white corpuscles are to be regarded as the
"escaped nuclei" of the red blood corpuscles. The facts adduced to
disprove the former notion respecting them, are likewise sufficient to
show the fallacy of that just referred to.
By Dr. Martin Barry the white corpuscles are considered to be the
last stage of the development of the red blood disc, and he has
assigned to them the designation of "parent cells," under the impres-
sion that the granules, of which many are contained in each corpuscle,
become developed into new blood discs; this idea of Dr. Barry is
purely hypothetical, and its accuracy is but little probable.
Mr. Addison also believes that the white corpuscles represent an
advanced condition of the growth of the red blood disc, but he differs
from Dr. Barry, however, in not considering them to be parent cells,
filled with young embryos, designating the white corpuscles "tissue
cells," under the belief that they become incorporated with, and
constitute an integral portion of the solid structures of our frame- work.
The value of this theory has already been discussed.
Mandl denominates the white corpuscles "fibrinous globules," and
he conceives that the nuclei, which he states belong to all red cor-
puscles of the blood, as well as the white globules, are not primary
formations, but secondary; that these structures do not exist in the
blood while circulating within the body, but that they are formed after
its abstraction therefrom; and M. Mandl further states, that the steps
of the formation of the white globules may be witnessed on the port
object of the microscope. That this view is incorrect, not the shadow
of doubt can be entertained. The regular form and size of the white
globules, their presence in the blood the moment after their abstraction
from the system, but especially the fact that they may be seen in vast
quantities in that fluid while still circulating in the capillaries, all
negative the idea of the formation of the white globules out of the
system, in obedience to a mere physical law.
Mr. Wharton Jones, in a recent communication made to the Royal
Society, has bestowed upon the white corpuscles the appellation of
"granule cells," and that gentleman considers them to represent an
early stage in the development of the red blood globule. The peculiar
views entertained by Mr. Jones will, however, be referred to more
fully under the head of the origin of the red^lood disc.
112 ORGANIZED FLUIDS.
The white corpuscles are also synonymous with the "exudation
corpuscles" of many writers, and especially of Gerber, who has under
this denomination assigned to them a false value ; the presence of the
white corpuscles in the plastic fluid of exudations being rather
accidental than essential.
We come now to refer to the opinion entertained respecting the
white corpuscles by Muller, who denominated them " lymph corpus-
cles," conceiving them to be identical with the granular corpuscles
encountered in the lymphatic fluid. Of all the opinions and theories
of the nature of the white corpuscles alluded to, that of Muller is
probably the only correct one ; Muller, however, was not acquainted
with their existence in the blood of mammalia, but merely in that of
frogs and other analogous animals.
The opinion that the white corpuscles are red blood globules in pro-
cess of formation, is one which is maintained by many observers, and
nevertheless I regard it as erroneous. In the truth of this view, Wagner,
Baly, Gulliver, Professor H. Nasse, and, above all, Donne, are believers.
From the excellent work of the latter writer I introduce the following
remarks in relation to this point :
"About two hours after injection (with milk), rabbits, dogs, and
birds have been opened. I have collected the blood in the different
organs, in the lungs, the liver, and the spleen ; every where I have
found the blood in the state in which I have described it above,
containing a certain number of white globules in all stages of formation,
and of red globules more or less perfect : invariably the spleen has
presented to me special circumstances so established and so constant
that it behooves me to mention them, and especially since they may
throw light, at length, upon the true functions of this organ, so long
and so vainly sought. I do not dare flatter myself with having com-
pletely resolved this problem, and it is but with reserve that I express
myself in this particular.
"The blood contained in the large vessels of the spleen offers
nothing very remarkable ; but, in expressing that which is enclosed
and, as it were, combined with the tissue of this organ, one finds in
it a composition well worthy of fixing the attention. In a word, this
blood is so rich in white globules, that their number approaches
nearly to that of the perfect blood globules ; but, further, the white
globules which are there, present in as evident a manner all the
degrees of formation an& development, and the examination of this
THE BLOOD. 113
blood does not appear to me to leave any doubt upon the transition
which I have pointed out above of white globules to red corpuscles,
and upon the successive phases through which the white globules pass
to arrive at the state of perfect blood globules. This phenomenon is,
above all, striking, after injections of milk, and during the work,
which is accomplished in the space of four-and-twenty hours, of the
transformation of the immense quantity of milk globules into blood
globules. One cannot believe that this is not really the point — the
laboratory, if one may so speak — in which this transmutation is
effected, and that the spleen is not the true organ of this important
function. But I know how like facts, and how the theory which
results from them, have need to be confirmed by the researches of
other observers, to be definitively adopted with confidence."*
In answer to these observations of M. Donne, I would remark, first,
that I have never seen the different stages of formation of the white
corpuscles, and of transformation of these into red, described by M.
Donne ; and, second, that I believe that he has totally misinterpreted
the appearances presented by blood pressed out of the spleen. The
cells or corpuscles, of which that organ is itself constituted, so closely
resemble the white globules of the blood, that I feel assured that M.
Donne has failed to discriminate between the two, and that many of
his progressive stages of development are to be referred to the splenic
cells or corpuscles, numbers of which are always contained in every
drop of blood procured from the spleen.
Having now noticed the various opinions held by different observers
in reference to the nature of the white corpuscles, we will next pass
to the consideration of their origin or mode of formation. The idea
that the white corpuscles are elaborated by the lymphatic glands, has
already been referred to ; and, from the absence of these glands in the
lower oviparous vertebrata, it is evident that they cannot be regarded
as essential to their formation.
It has been stated that, in addition to the white and red globules,
numerous smaller particles, termed molecules, exist in the blood.
The white globules, in all probability, derive their origin from these
molecules, a number of them going to constitute a single white globule.
This aggregation of the molecules into masses, or globules, would
appear to result from the operation of a general law of the economy,
under the influence of which the globules unite with each other,
* Cours de Microscopie, pp. 99, 100.
8
114 ORGANIZED FLUIDS.
and become invested with a coating, or membrane, probably of an
albuminous nature.
Donne" believes also that he has traced, by direct observation and
experiment, the transformation of the minute oily and fatty particles,
found in the milk, into white globules. He injected numerous animals,
birds, reptiles, and mammalia, with various proportions of milk, and,
strange to say, the creatures thus experimented upon experienced no
injurious effect beyond a momentary shock, with, however, the single
exception of the horse, to which the experiment proved fatal in seven
different cases. If, almost immediately after the injection of the milk,
a drop of blood be withdrawn from the system at a distance from the
point where the milk was introduced, a number of the globules of the
milk may be detected quite unaltered, and which may be recognised
by their general appearance, their smaller size, and, lastly, by the
action of acetic acid, which dissolves the red globules, renders apparent
the granular texture of the white, but leaves untouched the molecules
of the milk. If the blood be again examined at about the expiration
of two hours, the smallest milk globules will be seen to have united
themselves with each other by three's and four's, and to have become
enveloped, by circulating in the blood, in an albuminous layer, which
forms around them a vesicle, analogous to that which surrounds the
wThite globules. The largest remain single, but are equally enveloped
in a like covering. These soon break up into granules, in which state
the milk globules bear a close resemblance to the white globules of
the blood, from which, finally, they are not to be distinguished. " The
blood," Donne remarks, "then shows itself very rich in white globules ;
but, little by little, these undergo modifications more and more pro-
found; their internal molecules become effaced, and dissolve in the
interior of the vesicle, the globule is depressed, and soon it presents a
faint yellow colouration : they yet resist better the action of water
and acetic acid than the fully-formed blood globules, and it is by this
that they are still to be distinguished. At length, after twenty-four
hours, or, at latest, after forty-eight, matters have returned to their
normal state; no more milk globules are to be found in the blood, the
proportion between the white globules and the blood globules, between
the imperfect and the perfect globules, has returned to what it is
ordinarily: in a word, the direct transformation of the milk globules
into blood globules is completed."
In the opinion that the milk globules are convertible into the white
globules of the blood, Donne1 is probably correct, although it must be
THE BLOOD. 115
an inquiry of much delicacy and nicety to determine this point by
direct observation. The evidence, however, in favour of his latter
position, viz : that the white globules become ultimately converted
into red corpuscles, is much more defective, and the facts upon
which he relies to sustain this view are open to question, as we have
already seen.
The view, then, of the transformation of white corpuscles into red,
I consider to be erroneous, and that the white corpuscles, as they
differ from the red, in form, structure, and chemical composition, so
they also differ in origin; and that the two forms of corpuscles are
in every respect distinct, as well in function as in origin.
From the fact of the white corpuscles of the blood being encoun-
tered in considerable quantities in the lymph and chyle, which is in
truth blood in its primitive form, it is in those fluids, doubtless, that
they take their origin, and it is in them that they are best studied.
Origin of the Red Globules. — It has already been shown that
Donne and others consider that the red globules are formed out of
the, white, which they view as true blood globules which have not
reached the last degree of elaboration. Donne sustains this opinion
by reference to the following particulars: First, that among the red
globules contained in a single drop of blood, all are not affected to the
same extent by the use of the same reagent; that some resist its
influence for a much longer period than others ; Secondly, he states,
that he has observed in some true blood globules traces of a slight
punctuation, similar to that which is seen in the white corpuscles;
and, Thirdly, in certain white globules he has noticed the compressed
form common to the red corpuscles. From the observation of these
facts, he draws the conclusion that the white globules are transformed
into red blood discs. The first particular alluded to, viz: that the
same reagent does not affect equally all the red globules of the same
blood, is doubtless to some extent correct, and may be explained by
supposing that the red corpuscles are not all of the same age, and
therefore are of different degrees of consistence. The remarks as to
the granular texture of true blood corpuscles, and the compressed form
of certain white globules, it has never happened to me to be able to
verify in a single instance; and, for my own part, therefore, I am
inclined to allow to them but very little weight in determining the
question of the origin of the red corpuscles of the blood. To the
views of M. Donne on this point a high degree of plausibility and
ingenuity must certainly be accorded ; but in considering this question,
116 ORGANIZED FLUIDS.
not merely the doubtful and even debateable nature of the evidence
adduced by M. Donne must be taken into consideration, but also the
following fact, viz: that no definite relation exists in the animal
kingdom between the size of the red and white globules compared
together. In man, and most mammalia, the white globules are larger
than the red (see Plate I. fig. 1); in most reptiles, and particularly in
the blood of the frog, they are very much smaller (see Plate 11. fig. 1) :
from whence it would result that the process adopted by nature for
the conversion of the white globules into red, would, in the two
classes of the animal creation cited, be of a character wholly different
the one from the other. In the first-mentioned, the transmutation
would be a work of decrease ; in the second, of increase, or super-
addition ; and this supposition, I conceive, would be tantamount to
charging nature with the commission of a gross inconsistency.
There are other observers, again, who believe in the formation of
the coloured blood corpuscles out of the colourless ones, in a manner
totally different from that described by M. Donne.
Thus, Mr. Jones, in a communication recently made to the Royal
Society, and entitled "the Blood Corpuscle considered in its different
Phases of Development in the Animal Series," states that the blood
corpuscle presents throughout the animal kingdom at least two phases
of development : in the first of these, the corpuscle is granular, and in
the second, nucleated : when in the former phase, it is denominated
"granule blood cell," and in the latter, "nucleated blood cell;" the
first condition, or that of granule blood cell, is synonymous with the
colourless corpuscle of the blood.
But each of these two phases presents likewise two stages in their
growth or formation; thus the granule blodd cell may be either
coarsely granular, or it may be finely granular ; and the nucleated
blood cell may be either uncoloured or coloured. The first three
stages are encountered, according to Mr. Jones, in the whole animal
series, but not the fourth stage, the coloured condition of the nucle-
ated blood cell, which is wanting in most of the Invertebrata, and in
one of the series of Vertebrate animals, a fish, the Br ancliio stoma
lubricum Costa; in all the other divisions of the animal kingdom it is
present, as in the Oviparous Vertebrata and the Mammalia.
In the latter class, the Mammalia, a third phase is super-added to
the other two, that of a "free cellceform nucleus;" this appellation
expresses the usual condition in which the blood disc in the mammalia
is encountered, and in which no nucleus can be discovered.
THE BLOOD. 117
This third phase Mr. Jones considers to be derived from the
nucleated blood cell in its second stage; the "free cellaeform nucleus"
being the escaped nucleus of the nucleated blood cell.
The facts by which this view is supported are, first, a relation in
size between the nucleus of the nucleated blood cell and the ordinary
blood disc, or "free cellaeform nucleus," and second, the occurrence,
which is, however, very rare, of nucleated cells from which the nuclei
themselves have escaped.
The "nucleated blood cell" Mr. Jones found abundantly in the
blood of an embryo ox, an inch and a quarter long ; very sparingly in
that of the elephant and horse, and not at all in the blood of the human
subject; he encountered them, however, freely in the chyle of man.
Such is a brief statement of the views of Mr. Jones in reference to
the blood corpuscle, and of the chief facts by which those views are
supported. Without taking upon myself to pronounce upon them
decidedly, I yet must confess that they carry with them but little
conviction to my mind, and that the facts adduced to sustain them
are open to considerable discussion.
If the blood corpuscles of animals in general, and of the mammalia
in particular, pass through the successive phases and stages described
by Mr. Jones, how happens it, I would ask, that in the blood of mam-
malia, and especially in that of man, while we meet with so abundantly
the first stage of the first phase, that of granule blood corpuscle, viz :
the coarsely granular stage, and also the last phase indicated by Mr.
Jones, that of free cellaeform nucleus, we do not frequently encounter
the intermediate stages and phase, through which, according to Mr.
Jones, the blood corpuscles pass? To this question I do not think it
easy to give a satisfactory reply, consistent with the opinions of Mr.
Jones. The explanation which I would give of the absence of these
transition forms is, that they have no real existence.
According to Mr. Jones, the nucleated blood cells of the Oviparous
Vertebrata are of a nature totally distinct from the ordinary blood
cells of the Mammalia, which have no nuclei, but that the nuclei of
the blood cells of the former are the analogues of the latter; this
opinion is scarcely consistent with the difference of structure and
chemical composition observed between the two. Opinions very
analogous to those of Mr. Jones in reference to the nature of the
blood corpuscles of the mammalia, viz : that they are escaped nuclei,
appear to have been entertained by Mr. Gulliver from observations
made on the horse; this gentleman supposing that the red corpuscle
118 ORGANIZED FLUIDS.
was the escaped nucleus of the white granular corpuscle, while Mr.
Jones conceives that the red blood disc is the liberated nucleus of the
same body, only in an advanced condition of its development, in the
stage of coloured nucleated blood cell.
To the appellations by which Mr. Jones designates two of his phases
of the development of the blood corpuscle, an exception may fairly
be taken. The "granule blood cell" is frequently nucleated, even
while it still retains its granular structure, and therefore the term
selected by Mr. Jones to indicate a condition of the blood corpuscle
distinct from its granular state, viz : that of nucleated blood cell, is
inappropriate, and calculated to lead to the inference that the granule
blood cell is not a nucleated body.
I reiterate then the opinion, that the white and red globules of the
blood are wholly distinct from each other — distinct in origin, in
structure, and in function.
The strongest fact with which I am acquainted (but it is one which
is not employed by M. Donne) in favour of the transmutation of white
globules into red, is this, viz : that the nucleus which exists in the blood
discs of the frog, and reptiles in general, is of a granular structure, in all
respects similar to that of a white globule, with the differences only of
size and form, the nucleus being four or five times smaller than the true
white globule, and of an oval instead of a circular outline. (See Plate
II. fig. 5.) One of these differences, as already stated — viz : that of form
— is effaced by water, which renders the nucleus circular (see Plate II.
fig. 4), in which state the only distinction between it and a white cor-
puscle, which can be detected, is the single one of size. (See Plate II.
fig. 1.) This difference, however, is so great, and coupled with the fact
that no white globules have ever been detected in the frog, putting on
the characters of a true red blood corpuscle, that the opinion that the
white globules are transformed into red blood discs, must again be
abandoned. The existence of a granular nucleus in the blood discs of
reptiles, &c, revives again the old notion, that the white globules are
the escaped nuclei ; that they are not so, is proved by the fact that no
such nuclei exist in the true blood globules of man and the mammalia,
in the blood of which white corpuscles abound.* The blood discs, it
* The following interesting remarks of Mr. Gulliver tend to confirm somewhat the
views of M. Donne; they are by no means conclusive, however: — "White globules,
about the same size as those in the blood of man, and probably identical with the
proper globules of chyle and lymph, are common in the blood of birds, and particu-
larly abundant after a full meal in the vultures and other rapacious families.
THE BLOOD. 119
has been observed, first make their appearance in the chyle: any
inquiries, therefore, instituted with the view of determining their
origin and development in man, would be more likely to prove suc-
cessful if directed to the rigorous examination of that fluid.*'
In the last place, it remains to treat of the end or final destination
of the red globules of the blood.
THE END OR FINAL CONDITION OF THE RED GLOBULES.
Every where throughout the solid constituents of the animal organ-
ization, cellular tissue abounds ; it forms the basis of every texture and
organ of the body. It is, therefore, scarcely to be wondered at that
the opinion should have been adopted, that the globules which exist
in such vast numbers in the blood were to be regarded as the primary
and even parent cells, out of which all the solid structures of our
frame took their origin. f This theory, to the mind of the earlier
micrographer, must have appeared very rational and seductive; and
so great, indeed, is the plausibility with which, even in the present
Some of the red discs, too, instead of the oval form, are often nearly or quite circular
in figure. Hence the blood of these birds would appear especially favourable to
observe any changes in the white globules ; and it seemed highly probable that these
might be transformed into the blood discs in the manner mentioned by Dr. Baly; but
although I made many observations with the view of determining this question,
nothing but negative results were obtained." — (Appendix to Gerber's General Anato-
my, p. 24.) This observation is satisfactory in one respect, viz : that it shows clearly
the connexion, which has already been dwelt upon, of the white corpuscles with
nutrition.
* For further observations on the development of the red blood disc, see the
remarks on the circulation in the embryo of the fowl.
f Among those who regard the blood corpuscles as cells, may be named Schwann,
Valentin, Addison, Remak, and Barry. Schwann describes the blood globule as a
"nucleated cell," while Valentin considers it to be a nucleus, and that which is
usually held to be a nucleus he regards as a nucleolus. Remak states, that he
has witnessed the development of the globules as parent cells, not within the blood,
but within the cells which line the walls of the blood vessels and lymphatics. The
views of Addison are confined chiefly to the white globules, which he conceives to
be the fully-developed nuclei of the red blood corpuscles, and which he believes to
be transformed into epithelial cells, &c, &c. Dr. Barry goes further than this; for
he states that every structure which he has examined arises out of the blood corpus-
cle, "the crystalline lens itself, and even the spermatozoon and the ovum." The
opinions entertained by Gerber seem to be of a nature somewhat similar to the
foregoing. It is difficult to understand, however, what his exact sentiments are: they,
at all events, go to the extent of supposing that all the solid structures of the body
are derived from preexisting germs, contained in the chyle and blood.
120 ORGANIZED FLUIDS.
day, it is frequently invested, -that it is still able' to claim a few
adherents.
If we regard with the utmost patience and attention the beautiful
spectacle of the capillary circulation in any of the more transparent
parts of animals, but especially in the tongue of the frog, we shall in
vain look for the escape from their containing vessels of even a single
red blood corpuscle, independent of a rupture of those vessels. In a
normal state, therefore, the blood globules are never free, but are
always enclosed in their own proper receptacles.
A communication, however, between the fluid contents of the
blood vessels and the tissues lying external and adjacent to them, is
doubtless established, through the operation of the principle of exos-
mosis, whereby a slow exudation of the fluid fibrin of the blood is
perpetually going forward. Now, it is the opinion of most of the
German physiologists, and it is the view best supported by facts, that
this fluid fibrin is to be regarded as the true blastema, out of which
all the different elementary tissues and structures of the body proceed,
and this not by any power inherent in itself, it being, as respects the
final form which it is made to assume, totally inert and indifferent,
and which form is impressed upon it by a vis insita, or peculiar
power and faculty belonging to each organ and structure of the
animal fabric.
While the fibrin circulates in the blood it retains its fluid form ;
soon after the cessation of the circulation, and whether within or
without the system, it passes from the fluid state to the condition of
a solid. Now, on the principle of endosmosis, which has to be so
often referred to in the explanation of numerous phenomena, in the
solidifying power of the fibrin, and in the vis insita of the different
tissues, we recognise the chief and fundamental causes which regulate
nutrition, growth, and secretion.
It would thus appear that the globules of the blood (the red globules
are more particularly alluded to) are not to be regarded as either
cytoblasts or primary cells, forming by direct apposition the solids of
the body, and that therefore they do not express the last degree of
elaboration of which the fibrin of the blood is susceptible.
Again, then, we have to ask ourselves the question, what is the end,
or final condition, of the red blood globules? Direct observation is
wanting to aid us in the solution of this difficult inquiry, which,
however, admits of an indirect reply being given : we have seen that
no means of egress from the blood vessels is, under ordinary circum-
THE BLOOD. 121
stances, permitted to the red blood globules, and therefore we are
driven to the conclusion that, having performed the important func-
tion to which we have already alluded, viz: that of carriers of oxygen
from the lungs throughout the system, and of carbon from the latter
back again to the lungs, they become dissolved, increasing by their
dissolution the amount of fluid fibrin circulating in the blood, and
which is deemed to be the true blastema.
MOLECULES OF THE BLOOD.
In addition to the red and the white globules, there exists, as already
mentioned, in the blood a third description of solid constituent, the
"molecules:" these are synonymous with the "basin-shaped" granules
of Vogel, the "globulines" of Donne, and the "primary discs" of
Martin Barry.
The term molecule, or granule, is well suited to designate these
particles; for either appellation will serve to convey some idea of
their exceeding minuteness, and which is computed rarely to exceed
the 30^00 °f an inch. They occur in great quantities in the blood,
either scattered singly throughout it or agglomerated into small and
irregularly shaped masses. (See Plate I- fig- 6.) The molecules are
usually regarded as the elements out of which the blood corpuscles
are formed : on this point, however, direct observations are still want-
ing. It is more probable that the white globules are developed out
of them than the red, and this simply by their union or aggregation.*
PECULIAR CONCENTRIC CORPUSCLES.
Besides the red and the white globules and the molecules, which
we have described as present in the blood, a fourth species of solid
corpuscle has been observed to occur in its fibrinous constituent.
These corpuscles have been repeatedly encountered by Mr. Gulliverf
in clots of fibrin in man and other mammalia, and are alike to be
found in them, whether the clots are formed in the body after death,
or in blood abstracted from the system during life.
* Since the above few lines were written on the "molecules" of the blood, I have
repeatedly remarked that in blood, on its first abstraction from the system, but few
molecules were present, while in that which has been withdrawn from the body
for some time, they have always abounded. This observation has led me strongly to
suspect that the molecules do not exist in the blood in a free state, but that wherever
and whenever they are encountered, save only in the chyle, they are to be considered
as derived from the rupture and destruction of the white corpuscles.
f See translation of Gerber, p. 31, and Appendix, p. 16.
122 ORGANIZED FLUIDS.
These corpuscles, of a very peculiar structure, as will be seen
hereafter, Mr. Gulliver has described and figured with extreme accu-
racy; and he has styled them "organic germs," "primary or nucleated
cells," and as capable of further development if placed in circum-
stances favourable to their growth. Mr. Gulliver, however, would
appear to have been quite undecided as to their real nature, and
whether they were not to be regarded as identical with the "fibrinous
globules " of Mandl.
These peculiar bodies I have myself met with in fibrinous clots
which were found in the heart after death ; and I have no hesitation
in asserting that they differ, in every essential particular, from the
fibrinous globules of Mandl, which are identical with the colourless
corpuscles of the blood.
The size of these corpuscles is subject to the greatest possible
variation; they are frequently smaller than the white globules of the
blood, but very generally three or four times larger; their form is
also irregular, but inclining, in those I have examined, to the spherical.
They consist of two parts, of nuclei and envelopes : the nucleus is
of an irregular outline, and not usually well defined without the aid
of reagents; its bulk is about the one-fourth or one-fifth of that of the
entire corpuscle; the envelope, in all the globules which have fallen
under my observation, has been compound, that is, made up of several
vesicles concentrically disposed, the one within the other. (See
Plate IV. fig. 3.)
The appearance presented by these objects bears a close resem-
blance to the vesicles of certain species of Algae, of the genus
Microcystis or Hcematococcus, these being likewise each composed
of several concentrically arranged membranes or vesicles.
Now, what is the opinion which ought to be entertained in reference
to the nature of these corpuscles? Do they really constitute an
integral portion of our organization? and do they circulate in the
living blood? or are they formed in it after death? The opinion of
Mr. Gulliver that they are primary, or nucleated cells, has already
been referred to : my own impression as to them is, that they do not
constitute an integral portion of our frame; and that, whether they
exist in the living blood, and circulate in it, or are formed in the clot
subsequent to decease, they are to be regarded as extraneous forma-
tions, probably of an entozoal character.
It does not appear that the envelopes of all the corpuscles met with
by Mr. Gulliver exhibited concentric striae, although he describes
THE BLOOD. 123
some of them as possessing this striated structure : Mr. Gulliver
speaks also of cells three or four times larger than the corpuscles, and
capable of containing the latter as nuclei. These I have not myself
encountered.
The corpuscles are not usually scattered equally throughout the
fibrinous clot, but frequently occur in groups, parts of each clot being
altogether free from the corpuscles.
Acid reagents, especially the sulphurous acid, will be found useful
in their examination.*
*
BLOOD GLOBULES OF REPTILES, FISHES, AND BLRDS.
The red globules of the blood of the reptile, the fish, and the bird,
have all certain characters in common with each other, which serve
to distinguish them from those of man and the mammalia in general.
The chief of these characteristics are their form, their size, the
presence of a nucleus, and, lastly, their greater consistence. The
compressed form belongs to the red blood globules of all animals ; in
the three classes of reptiles, fishes, and birds, however, although the
globules possess this flattened figure, instead of being circular, as in
man and the mammalia, they are in outline elliptical ; and, in place of
having a central depression, this part of each globule is slightly pro-
tuberant. This prominence is due to the presence of a nucleus,
which in the mammalia we have seen to be absent.
The size of the red globules is as distinctive as their form, it usually
exceeding, in reptiles, three or four times that of the majority of the
blood corpuscles of mammalia. The blood disc of the frog equals in
length the ttV j of an inch, while its traverse measurement is not less
than the tgVj °f an inch; now the corpuscle of the elephant, the
largest known among mammalia, reaches only the stV s °f an mcn m
diameter, f
It has already been remarked that most of the animals of the order
Camelidce are possessed of blood globules of an elliptical form, con-
stituting in this respect an exception in the class to which they
belong. These oval corpuscles are, however, so small, that they
* Since writing the above description, I have met with these concentric corpuscles
in connexion with the thymus gland which had been allowed to remain in water for
a few hours.
f The largest blood corpuscles hitherto discovered in the animal kingdom are those
of the Siren and Proteus. In the Siren, according to Mr. Gulliver, the long diame-
ter of the blood discs is the 435th, and the short the 800th part of an inch, while
in the Proteus they are stated at about the 350th part of an inch in length.
124 ORGANIZED FLUIDS.
could not be readily confounded with the elliptical globules of the
frog, &c. ; they therefore agree in size, as well as in the absence of a
nucleus, with the blood corpuscles of other mammalia, although not
in form. While every possible care has failed in satisfactorily
demonstrating the presence of a nucleus in the blood of mammalia,
not the slightest difficulty is experienced in detecting it in that of the
frog and most of the animals belonging to the classes just mentioned,
and therefore its presence is generally recognised ; although one
excellent observer, M. Mandl, is of opinion that its formation takes
' place subsequently to the removal of the blood from the system : this
idea is doubtless erroneous, as we have seen to be the case with
respect to the white corpuscles of the blood, regarding which M.
Mandl entertained a similar notion. In blood corpuscles immersed
in their own serum, and examined immediately after their abstraction,
the nucleus may be seen with a sufficient degree of clearness to enable
the observer to pronounce with confidence upon its presence. After
the lapse of a few minutes, it becomes much more apparent, so that
its composition is easily to be discerned: this arises, most probably,
from the discharge of a portion of the colouring matter of each
globule. The form of the nucleus is seen to correspond with that of
the blood corpuscle itself, and to be oval, presenting a granular struc-
ture precisely resembling that of the white globules of the blood, from
one of which it is only to be distinguished by its much smaller size
and oval form. (See Plate 11. fig. 2.)
Owing to the firmer texture and greater size of the blood globules
of the frog, their structure can be well studied, and the effects of
reagents more easily determined.
In water, the red corpuscles lose their colour, and become circular,
and indeed globular, a change of form which the nucleus is likewise
seen to undergo. (See Plate II. figs. 3 and 4.) These alterations
ensue almost immediately on the application of the water; its con-
tinued action produces an effect still more remarkable; the nucleus,
which at first occupied a central position in the globule, is soon seen
to become eccentric, and finally, rupturing the pseudo-membrane of
the corpuscle, escapes into the surrounding medium; the nucleus and
the outer portion of each globule are then observed as two distinct
structures, lying side by side (see Plate II. fig. 4) ; the latter is at
length absorbed, and then nought remains but the nucleus, which is, as
already remarked, under the influence of water rendered of a globular
form, and which is in no way distinguishable from a white corpuscle
THE BLOOD. 125
of the blood, save in the single particular of size, the nucleus being
several times smaller than the globule.
Acetic acid dissolves (if strong, almost immediately) the outer
tunic, without occasioning the prior extrusion of the nucleus, the
form of which is not materially affected, the contained granules merely
becoming more clearly defined. (See Plate II. fig. 5.)
The white globules in the blood of the frog are very numerous;
they bear no similitude of form or size to the elliptical red blood cor-
puscles, being usually perfectly spherical, and scarcely more than a
third of the dimensions of the oval corpuscles. Thus, between the
white globules in man and the mammalia and those of reptiles, an
opposite relation of size in reference to the red blood discs exists; for
while, in the former, the white corpuscles are larger than the red
globules, in the latter they are generally much smaller. (See Plate I.
fig. 1, Plate II. fig. 1.)
The plastic property possessed by the blood globules of all animals
belongs especially to that of the frog. The globules, if trailed or drawn
along the surface of a piece of glass, may be elongated to thrice
their original length, and made to assume such forms as are altogether
inconsistent with the existence of a thin and distinct investing
membrane.* (See Plate II. fig. 6.)
CAPILLARY CIRCULATION.
We have now considered the blood, both physiologically and
anatomically, out of the system, at rest and dead. We have, in the
next place, to treat of it within the body, living and circulating.
The beautiful phenomenon of the capillary circulation may be
witnessed in the more transparent parts of several animals; as, for
example, in the extremities of young spiders, fins of fishes, in the gills
of the tadpole and the newt, in the tail of the water newt, in the
web of the frog's foot, and in the mesentery of the smaller mammalia.
But it is seen to the greatest possible advantage in the tongue of the
* The extraordinary elongation of which the blood globules of the frog are
susceptible, may be seen to very great advantage by adopting the following little-
expedient: — A drop of blood being placed upon the object-glass previous to its
coagulation, and allowed to remain there for a few seconds, until symptoms of con-
solidation have manifested themselves, it is then to be extended gently with two
pins in opposite directions; if now the microscope be brought to bear upon it,
elongated corpuscles will be seen in it in vast quantities. In the production of this
change, it is the fibrin which is mainly concerned; for it is through it that the exten-
sion is communicated to the corpuscles.
126 ORGANIZED FLUIDS.
frog; an organ peculiarly adapted for the representation of the cir-
culation of the blood, from its extraordinary elasticity and transparence.
For a knowledge of this fact, science is indebted to a neighbour and
friend of mine, Dr. A. Waller, and by whom it was communicated
some years ago to M. Donne. For the exhibition of the circulation
in the tongue of the frog, in a satisfactory manner, it is necessary
that the animal should be secured in the following way : — A bandage
having been passed several times around the body of the frog, so as to
secure effectually the anterior extremities, it is next to be fastened to
a piece of cork by additional turns of the bandage; this piece of cork
should be very thin, six or seven inches in length, by about ten in
width, and perforated at one extremity by a square aperture, the
diameter of which should not be less than two-thirds of an inch. To
the margin of this aperture, the mouth of the frog, in binding it to the
piece of cork, should be brought. The frog having been thus effect-
ually secured, the soft and pulp-like tongue should be drawn out of
the mouth by means of a pair of forceps, and being spread over the
surface of the aperture, should he retained in position by from four
to six pins, the elasticity of the tissue of the tongue allowing of its
extension into a thin and transparent membrane with but little risk
of a rupture of the organ; lastly, the piece of cork should be fastened
to the stage of the microscope, in such a position that the tongue
rests over the opening in the stage. These preliminary arrangements
being effected, and a low power of the microscope being brought to
bear upon it, a spectacle of the highest interest and beauty is revealed
to the sight of the beholder. We have displayed before us, in action,
almost every tissue of the animal organization, in its simplest and
clearest form and disposition — arteries, with their accompanying veins
and nerves; muscular tissue; the blood, with its red and white
globules; epithelial cells; glands of the smallest possible complication
of structure ; and these several parts are not merely visible, but their
form, disposition, construction, and normal mode of action, are all
distinctly apparent ; the blood ever flowing, the muscles contracting,
and the glands secreting.
The circulation in the tongue of the frog is best seen, in the first
instance, by means of low powers, a larger surface of the organ being
thus brought under view, and a more exact idea obtained of .the
relative size and disposition of its numerous constituents. The
arteries may be distinguished from the veins by their fewer number,
smaller calibre, and by the fact that, while the veins increase in
THE BLOOD. 127
diameter, in the direction of the course which the blood contained
in them pursues, the arteries decrease in the course which the
current follows in them. The arteries, from their origin, diminish
in size and multiply in number, by the constant giving off of second-
ary branches ; the veins, on the contrary, become enlarged during
their progress, and lessen in number, by the continual addition of
subsidiary veins. These differences, as well as the circumstance that
the velocity of the blood in the arteries is greater than in the veins,
are abundantly sufficient to distinguish the two orders of vessels from
each other. If, now, a somewhat higher power be applied to the
objects, we shall be able to dive still further into the mysteries of
organization ; we shall not merely perceive the general motion of the
blood, but also that nearly the entire mass of that fluid consists of red
globules. We shall be able to recognise clearly their form, and to
see the different modifications of shape which they undergo in passing
by each other, and in escaping any impediment which presents itself
to impede their progress. We shall perceive, likewise, that, in the
smaller capillaries, the globules circulate in single series, and mingled
with them will be noticed occasionally a colourless globule, which, in
the blood of the frog, is not more than half the size of the elliptical
corpuscle. (See Plate V. fig. 2.) Furthermore, it will be remarked
that the circulation does not flow on in an uninterrupted stream of
equal velocity, but that certain arrests of its motion occur. These are
but momentary, and after each the current again quickly flows on
with the same speed as before ; with each action of the heart, also, a
slight impulsion of the blood in the capillaries may be clearly seen.
This instructive sight of the capillary circulation may be viewed
thus for hours, during the whole of which time the blood will be seen
flowing on with undiminished force. In certain vessels, however,
after a very long exposure of the tongue to the action of the air,
wrhereby its moisture is continually abstracted, and which acts,
doubtless, as a source of irritation, a number of the colourless globules
will be seen to have collected in the capillaries; these adhere prin-
cipally to the sides of the vessels and to each other, thus leaving
the channel still free for the passage of the red globules, which in
their course sometimes rush against the white globules with such
violence as to detach one or more of them from time to time from its
adhesion to the walls of the vessel, and which, rolling over once or
twice, joins the general current of the vessel, and is quickly carried
out of view. It would appear that any irritation affecting the
128 ORGANIZED FLUIDS.
capillary vessels, even when applied to them outwardly — as, for
example, weak chemical solutions — gives rise to the phenomenon in
question. It is to be observed, however, that at all times considera-
ble numbers of white corpuscles circulate in the larger capillaries :
these do not occur mixed up with the red blood corpuscles ; but, as
already remarked, are situated externally between them and the inner
wall of the capillaries. (See Plate ^.fig- 1.)
In the plastic power with which the red corpuscles are endowed,
we recognise a beautiful and important organic adaptation of matter
to the fulfilment of a special purpose. Were it not for this plastic
property, and were the red corpuscles of the blood, on the contrary,
of a solid and unyielding texture, it would follow, as an inevitable
consequence of the solidity of the globules, combined with their vast
number, that frequent interruption and stoppage of the circulation in
the capillaries would ensue, and which would, of course, result in the
complete derangement of the functions of the entire economy.
I come now to record an observation which, so far as I am informed,
is without parallel. On one occasion, in examining the tongue of a
frog, a portion of it broke away from the remainder; this I placed
between two plates of glass, and submitted to examination, when,
extraordinary to say, it was perceived that the circulation was still
vigorously maintained in the majority of the vessels. Anxious to
know how long this circulation would be continued, but fully expecting
to see it cease every moment, myself and a friend, John Coppin, Esq.,
of Lincoln's Inn, watched it for upwards of an hour, at the end of
which time the blood still flowed onwards in many of the vessels,
with scarcely abated vigour, though in others, often the larger ones,
the motion had altogether ceased. The mutilated portion of the
tongue was then placed in water, in which it remained during the
whole of the night; the next morning it was again examined, when
it was found that a tolerably active circulation still existed in several
of the smaller vessels. After this observation, the further examination
of the fragment was abandoned. The almost immediate cessation
of the circulation, which occurred in some of the larger vessels,
admits of explanation in the following way: — In some vessels, the
blood globules were seen escaping from their open extremities; this
effusion of the globules frequently continued for two or three minutes,
until the entire contents of such vessels became poured out, when of
course the circulation within them ceased, the circulating fluid being
expended ; in other capillaries, the current was seen to stop long
THE BLOOD. 129
before their contents had been exhausted, in which case it was usually
to be remarked that some of the blood corpuscles contained in the
vessels had collected around their orifices, thus producing an impedi-
ment to the further maintenance of the current.
The foregoing observation is one of much interest and importance;
for it seems to prove that the capillary circulation is in a great
measure independent of vital influences, and that its persistence is
mainly due to physical agencies.
With a few observations on the mucous follicles situated on the
upper surface of the tongue of the frog, we shall conclude our relation
of the capillary circulation, as witnessed in that organ. These
follicles are glands reduced to the simplest possible amount of organ-
ization: they are of a regularly spherical form, and transparent
texture ; they are situated in the mucous membrane of the tongue, to
the thickness of which they are entirely confined, as proved by the
fact that, when that membrane is dissected off, by means of a needle
the glands are raised along with it. Into each of these glands may be
seen entering it on one side, and quitting it usually on the opposite, one
of the smallest of the capillary vessels, in which the blood corpuscles
pass usually in single series; this vessel in its passage through the gland
describes usually a tortuous course ; and within it the blood corpuscles
are seen to be in a state of increased and incessant activity, appearing
to move, as it were, in a vortex, this appearance resulting from the
curvatures described by the vessel. (See Plate VII. jigs. 1, 2.)
It might be expected that, in a gland of such simple constitution,
the exact process of secretion would be rendered apparent ; in this
expectation, however, we are doomed to disappointment, no action
beyond that which we have already related being visible within it. An
endosmotic action does doubtless take place between the contents of
the gland and those of the vessel which permeates it, whereby a peculiar
product is obtained from the blood, to be fashioned and assimilated
by certain powers inherent in the gland itself, and the precise nature
of which powers is unknown to us, and it is probable that it never
will be revealed. Pass we now to the description of. the circulation
in the embryo of the chick, which possesses points of interest distinct
from those observed in the tongue of the frog.
CIRCULATION IN THE EMBRYO OF THE CHICK.
The process by which the circulation in the embryo of the chick
is displayed is one which requires considerable delicacy of manipu-
9
130 ORGANIZED FLUIDS.
lation ; the care, however, which it is necessary to bestow upon it,
for its successful exhibition, is amply repaid by the surpassing beauty
of the spectacle which presents itself to the beholder. It is best seen
in the third, fourth, and fifth days of the incubation of the egg.
For the purpose of showing it satisfactorily, the egg should be broken
at the side, and a portion of the shell cautiously removed, without at
the same time raising with it the subjacent membrane (membrana
testae) ; this should next be peeled off with the same degree of caution
as that with which the shell itself was previously raised.
Immediately beneath this membrane, the tyolk itself will be seen
floating in the midst of the colourless albumen, and sustained in posi-
tion by the beautifully spiral chalazce, which, proceeding from the
yolk, are fastened into that portion of the membrana testes which cor-
responds with the poles of the egg-shell.
Imbedded in the surface of the yolk of an egg, on the third, fourth,
and fifth days of its incubation, the embryo will be visible, and issuing
from its umbilicus will be seen the vessels which ramify in such
graceful order through the membrane of the allantois.
The embryo is almost invariably placed uppermost in the yolk, so
that it most generally presents itself beneath, whatever part of the shell
has been broken. This position results from the lighter specific grav-
ity, and is, moreover, facilitated by the spiral formation of the chalazse.
The purposes fulfilled by this position of the embryo are obvious
and striking, it being thus so placed as to receive directly the caloric
which is continually emanating from the parent hen, and being also
more immediately submitted to the influence of the oxygen of the air.
In an embryo then thus placed in situ, in the third, fourth, and fifth
days of its development, and with the unaided sight, the rudiments of
almost all the organs and members may be clearly recognised, the eye
and the regular contractions of the heart, together with the vessels
departing from it to ramify through the area vasculosa being particu-
larly conspicuous. With a low power of the microscope, the course
of the blood in the vessels, together with the form and size of the white
and red corpuscles, may be clearly distinguished.
The ramifications of the vessels in the area vasculosa present an
arborescent distribution ; their entire course may be traced from their
commencement in the aorta to their termination on the border of the
membrane of the area vasculosa.
Now, the great point of interest in the circulation of the chick is
that the passage of the blood may be witnessed throughout. Thus,
THE BLOOD. 131
the blood expelled from the heart by the contraction of the ventricle
into the aorta, may be traced through this vessel, and all its subse-
quent divisions and sub-divisions, until it reaches the ultimate arterial
radicles, passes from these into the corresponding radicles of the veins,
and from these again into the larger venous trunks, by which it is
reconveyed to the heart, the circle of the circulation being thereby
completed.
There are two ways in which the circulation in the embryo of the
fowl may be viewed, either while it is still occupying its natural posi-
tion on the surface of the yolk, (and this I think is by far the most
preferable method,) or the embryo may be altogether detached from
the yolk by means of an armed needle, and subsequently placed on a
watch-glass filled with warm water at a temperature of 96°. During
the operation of detaching the embryo, the egg itself should also be
immersed in water at the temperature just mentioned. This latter
process is one, however, of much nicety, and frequently fails in con-
sequence of the rupture of some of the finer vessels, the blood becom-
ing effused, the different parts of the embryo obscured, and a stoppage
put to the circulation.
But it is not alone the contemplation of the circulation in the
embryo of the chick which is so interesting and instructive; the study
of the entire development of the ovum, from its commencement to its
termination, reveals facts of the highest importance, and full of wonder.
The examination of the blood of the embryo fowl is especially
instructive, the mode of formation of the red corpuscles admitting of
determination in a manner the most satisfactory.
In the red corpuscles contained in the blood of the embryo in the
first days of its development, a remarkable variation of size will be
detected, some of them being three or four times larger than others,
and the smallest consisting almost entirely of a nucleus surrounded by
a faint and delicate envelope. Between the two extremes of size,
every possible gradation is presented. (See Plate IX. fig. 1.)
This variation in the dimensions of the corpuscles becomes scarcely
less apparent if they be immersed in water, in which they become
perfectly spherical. (See Plate IX. fig. 2.)
A diversity of size, almost as remarkable as that which exists
between the red blood corpuscles of the embryo fowl, will be observed
also in those of the young frog which has but just emerged from its
tadpole state. If a drop of the blood of this young frog be compared
with that of a full-grown frog, the corpuscles in the former will be
132 ORGANIZED FLUIDS.
remarked to vary greatly in dimensions, while in the latter they will
be seen to present a much greater uniformity of size. (See Plate IX.
figs. 4, 5.)
Now, the inferences to be deduced from this great diversity of size
are palpable, and are, first, that the red blood corpuscle is at its origin
small, and only attains its full dimensions after a given period ; and,
second, that the nucleus is the part of the corpuscle which is first
formed, the coloured investing and perfectly smooth portion of it being
gradually developed around this subsequently. This view is incon-
sistent with the notion entertained by many, that the red blood cor-
puscles result from the gradual assumption by the white globules of
the characteristic distinctions of the red blood discs ; for were this
really the case, we should be at a complete loss to account for the
remarkable differences of size to which we have adverted.
A similar mode of development to that which has been described as
belonging to the red blood corpuscles of the embryo fowl, appertains
also, I believe, to that of all the Oviparous Vertebrata.
The development of the coloured blood corpuscle of the Mammalia,
I conceive to agree also with that of the other Vertebrata in the fact
of its being small at first, and subsequently and gradually attaining its
normal proportions, but to differ from that of the Oviparous Verte-
brata in not being developed around a central nucleus.
DISSOLUTION OF BLOOD CORPUSCLES.
But if the blood of the embryo fowl is well adapted for the study of
the origin and development of red blood corpuscles, that of the adult
fowl is no less fitted for ascertaining their end and final destination.
Some observers have entertained the idea, already expressed in this
work, that the older blood discs become melted down in the liquor
sanguinis, and thus, by their dissolution, increasing the amount of
fibrin held dissolved in that liquid. To the adoption of this notion
they were driven, because they were unable to dispose of the red
blood disc in any other way, and which other facts had made apparent
to them could not be regarded as persistent structures.
In proof of the accuracy of this statement respecting the melting
down of the corpuscles, they had not, however, a particle of direct
evidence to adduce. I will now proceed to show that the view refer-
red to may be substantiated by positive observation.
In almost every drop of the blood of an adult fowl, a number of
certain pale and usually colourless corpuscles will be seen, having a
THE BLOOD. 133
nucleus of the same size and structure as that of the ordinary red
blood disc distinctly visible in the midst, the investing portion of each
corpuscle at the same time being invariably smooth and destitute of
granules.
These corpuscles vary in size, in form, and in colour; the larger
ones, which are equal in dimensions to the fully-developed blood discs,
usually retain a faint colouration, and are invariably of an oval form ;
while the smaller ones, many of which consist of merely a nucleus
and a closely-fitting envelope, are perfectly colourless, and for the
most part, although not always, spherical. (See Plate lH-fig. 3.)
Now, there is no difficulty whatever in detecting these pale and
mostly spherical corpuscles with a good instrument, nor is there the
slightest danger of confounding them with the white corpuscles, which
are also to be seen retaining their uniformly molecular aspect.
The corpuscles just described exist not merely in the blood of the
adult fowl, but they may be detected, with similar facility, in every
Oviparous Vertebrate animal the blood of which I have examined;
and they abound in the blood of tritons and frogs. (Plate IX. j6g\ 5.)
But further, there may be detected in the blood of adult Oviparous
Vertebrata, not merely the delicate and pale corpuscles referred to,
but also numbers of naked nuclei — that is, of nuclei deprived of all
trace of investing membrane. (See Plate IX. figs. 3 and 5.)
These nuclei should, however, be examined with care, and a nice
adjustment of the object-glass ; for it will be found, on close examin-
ation, that many of them, though appearing at first sight to be naked,
are not really so, but are invested by a scarcely-perceptible envelope.
Now, these large and slightly-coloured oval corpuscles, the smaller
perfectly colourless and mostly spherical ones, and the naked nuclei,
represent progressive states of the dissolution of the red blood disc.
When first I noticed these pale corpuscles and nuclei, I was dis-
posed to think that they represented stages in the upward develop-
ment of the red blood disc : this opinion was, however, dispelled, by
observing that the pale and colourless corpuscles often exceeded
greatly in size the smaller true and coloured blood corpuscles.
There is one circumstance connected with these pale corpuscles
which does not appear to admit of any very satisfactory explanation,
viz : their occurrence on the field of the microscope in groups.
A word or two as to the seat or locality in which the wTork of
development of blood corpuscles, and subsequent dissolution of them,
is conducted. Physiologists appear always to have been on the look-
134 ORGANIZED FLUIDS.
out for some organ of the body, the especial purpose of which in the
animal economy they conceived should be the elaboration of the blood
corpuscles; and some of them, as Hevvson and Donne, not knowing
well what office ought to be assigned to that much-discussed organ,
the spleen, have on various grounds considered it to be the laboratory
in which the work of development is carried on. Of the dissolution
of the red blood discs, no definite or decided observations hitherto
appear to have been made by any observer.
Observation has convinced me that the development of blood cor-
puscles is not assigned to any particular organ of the body, but that it
occurs within the blood-vessels during the whole course of the circu-
lation and of life. During the first formation of the blood in early
embryonic life, the corpuscles are said to be formed in the cells,
which by their union with each other give origin to the capillary
vessels.
Further, it is probable that, while it is in arterial blood that the
work of development of blood corpuscles is most active, it is in the
venous fluid that the converse work of dissolution is mainly effected.
The development of blood corpuscles is also most active in very
early life, when growth is rapid ; and it is likewise more active than
ordinary in adult existence, after haemorrhages, and in persons of the
plethoric diathesis. In like manner it may be presumed that the dis-
solution of red blood corpuscles proceeds more quickly in anaemic
conditions of the system, and in old age, while at the same time, at
the latter period, development of new corpuscles is more tardy.
It is now hoped that a more satisfactory explanation of the origin
and end of the red blood disc has been given than it was feared, when
the writer first approached the consideration of these difficult, though
most important, questions, it would have been in his power to have
afforded.
VENOUS AND ARTERIAL BLOOD.
Venous and arterial blood differ in certain important respects from
each other; arterial blood is of a brighter colour, and coagulates more
firmly than that which is venous. The difference in colour is due to
the presence in the former of oxygen, and in the latter of carbon in a
state of combination not yet well determined. Venous blood, when
exposed to the action of oxygen, soon acquires the vivid red colour of
arterial blood, and this, when submitted to the influence of carbonic
acid, as speedily assumes the dark hue of venous blood.
The greater or less firmness in the clot formed is owing to the
THE BLOOD. 135
different amount of fibrin contained in the two fluids, and which is
greatest in that which is arterial ; the coagulum of which, therefore,
possesses the greatest density. The differences detected by the
microscope in the blood corpuscles of arterial and venous blood are
scarcely appreciable. Gerber states that the "tint of colour exhibited
is various ; bright in the globule of arterial blood, dark red and some-
what streaky in that of venous blood :•" this difference of colour, which
doubtless exists, it is easier to infer than positively to demonstrate by
means of the microscope. While arterial blood is richer in salts,
venous blood contains a greater proportion of fatty matter.
There are several substances which effect a change in the colour
of the blood : thus, oxygen, the concentrated solutions of salts with an
alkaline base, and sugar, turn dark venous of a bright florid or arterial
red ; this reddening being accomplished by the salts and sugar, even
when the blood is placed in a vacuum, or an atmosphere of hydrogen,
nitrogen, or carbonic acid gasses.
Newbigging* hath also remarked that venous blood takes the tint
of vermilion in a cup, at those situations at which it is painted with
the green oxide of chrome ; and Taylorf has confirmed the observa-
tion that the colours which contain the oxide of chrome brighten the
tint of blood.
On the other hand, bright or arterial blood is darkened, or even
blackened, by contact with carbonic and oxalic acids, and by its
admixture, according to Henle, with distilled water.
Sulphuric acid, and other acids which are agitated with the blood,
change its colour from red to blackish brown.
The nitrous and nitric oxides cause vermilion blood to take a deep
purple tint. J
The power possessed by those substances which brighten the colour
of dark venous blood, is supposed to be derived from the oxygen
which they contain, and by means of which a chemical transforma-
tion in the condition of the red element of the blood, the hematine, is
effected, a portion of oxygen being absorbed during the change of
colour. Those substances, however, which cause arterial blood to
assume the tint of venous blood, are presumed to exert their influence
by means of the carbon of which they are compounded, and a portion
of which becomes imbibed during the work of transmutation.
* Edinburgh New Philosophical Journal, October, 1839.
f Lancet, February, 1840.
| Henle, Anatomie Generale, tome premier, page 471.
136 ORGANIZED FLUIDS.
Henle, nevertheless, considers that these several alterations of
colour arise rather from mechanical than chemical causes, and that
they depend upon the state of aggregation of the particles of the
colouring matter, these being differently disposed according to the
nature of the reagent employed.
Thus, Henle remarks*, " It is evident that the colour of the blood
is brightened under the influence of substances which oppose the dis-
solution of the hematine in the serum, and maintain or reestablish the
flat form of the corpuscles, as the concentrated solutions of salts and
of sugar ; while pure water, which dissolves the colouring matter, and
causes the corpuscles to swell, deepens the colour of the blood."
Hamburgerf , according to Henle, has even observed that weak
solutions of the chlorides render the colour of the blood deeper, while
their concentrated solutions make it pass to vermilion.
Again, according to the observations of Schultz, it would appear
that the red blood corpuscles are flattened by the action of oxygen,
while the effect of the application of carbonic acid is to cause them
to swell up, and assume a more or less globular figure.
On this fact, Henle reasons thus : Accompanying these changes of
form there are alterations in the state of aggregation of the colouring
matter of the corpuscles; thus, in oxygen, or in any saline solutions,
the plasma remains clear and colourless, the blood discs being flat-
tened, and the colouring matter contained within them condensed;
while in carbonic acid or water the plasma becomes coloured, by the
escape of a portion of the hematine from the corpuscles, which swell
up, and assume a form approaching more or less the globular.
Now, the difference in colour between venous and arterial blood
Henle maintains may be accounted for by reference to the form of
the corpuscles, and the consequent condition of the particles of the
colouring matter.
And it is also by reference to the state of the colouring matter that
Henle accounts for the fact that blood which has once acquired a very
dark colour is thereby rendered incapable of reassuming the bright
hue of arterial blood on the application of oxygen or saline solutions,
because, he says, that the pigment which had escaped into the plasma,
under the influence of the carbonic acid, cannot be made to enter
into the corpuscles again, when by means of oxygen they are again
flattened.
*Loc. cit. page 471.
f Hamburger, Exp. circa Sanguinis Coagulationem, pp. 32. 42.
THE BLOOD. 137
The colour of the blood, then, according to Henle, depends upon
the single fact of the form of the corpuscle, and that this colour is so
much the more bright as these are flat.
Finally, in support of his theory, Henle refers to changes of colour
presented by certain inorganic substances from an alteration in the
state of aggregation of its constituent particles: thus, it is well known
that the ioduret of mercury recently sublimed is yellow; in cooling,
its colour passes to scarlet, and pressure determines this change in an
instantaneous manner.
Such is Henle's mechanical theory of the changes of colour expe-
rienced by the blood on the addition of reagents ; a theory which,
however ingenious it may be, I deem to be insufficient to account for
the very remarkable alterations of colour to which the vital fluid is
subject.
The changes of colour of dark blood to a vermilion hue, and of this
again to the deep tint of venous blood, admit of a chemical explana-
tion being given, the essential element of the former change being
oxygen gas, and of the latter carbonic acid gas. Thus, even the
remarkable effect of the application of the chlorides may be accounted
for by reference to the well-known operation of chlorine as a bleach-
ing agent, viz : through the power which it possesses of depriving
water of its hydrogen, and altering the state of combination of the
oxygen.
With respect to the observations of Schultz on the effect of carbonic
acid and of oxygen in altering the form of the red blood corpuscles,
and on which fact the entire of Henle's theory rests, I would observe
that, in conjunction with Mr. Miller, the gentleman who manifests so
much of patience, skill, and intelligence in the execution of the draw-
ings of this work, and who is moreover an excellent chemist, I have
made many experiments, with the view of ascertaining the power
possessed by the former reagent in modifying the form of the elliptical
corpuscles of the blood of the frog, the blood being in some cases
submitted to the direct action of the gas, and in others the animal
itself being subjected to its influence.
The result of these experiments, on my mind, is the conviction that
the effect of this gas on the figure of the corpuscle is not appreciable.
I am, therefore, disposed to allow but little weight to the mechanical
theory of the changes of colour experienced by the blood.
Venous blood does not present precisely the same tint of colour, or
the same characters in all parts of the system : thus, the blood found
138
ORGANIZED FLUIDS.
in the vena portse is deeper in colour than any other venous blood,
and, according to Schultz, it does not redden either on the application
of ox)Tgen gas or of salts, and does not coagulate, or gives but a divided
clot; it is richer in water, in cruor, and in fat, and poorer in albumen,
than ordinary venous blood.
It would be a point of much interest to determine whether arterial
or venous blood contains the greatest number of blood corpuscles.
The experiments which have hitherto been made, with the view of
determining this question, are most unsatisfactory, and contradict
each other.
MODIFICATION'S OF THE BLOOD CORPUSCLES THE RESULTS OF DIFFERENT EXTERNAL AGENCIES.
Peculiar Modification of the Effect of commencing Desiccation.
If the red corpuscles be examined a few minutes after their
abstraction from the system, in a drop of blood which has been spread
out between two plates of thin glass, it will be seen that many of
them, and especially those which are situated near the margin of the
drop, present an appearance very different from that which belongs
to them in their ordinary and natural condition. They now no longer
exhibit the flattened form with the central depression, but have become
converted into little spheres, the surface of which, instead of being
smooth, is now rough and tuberculated. (See Plate I. fig. 5.) Blood
corpuscles thus changed have been compared to mulberries in appear-
ance. This alteration is supposed by Donne to depend upon com-
mencing desiccation, and to arise from deficiency of serum, the
mulberry-like globules being but imperfectly bathed in that liquid.
No very satisfactory explanation of the exact nature of the change
has as yet been given. MjM. Andral and Gavarret* suppose that the
mammillated appearance of the corpuscles arises from the adherence,
to the surface of the globules, of a number of the exceedingly minute
molecules of the fibrin ; this explanation is probably more ingenious
than correct. If a number of the altered globules be carefully and
closely examined, it will be remarked that they do not all exhibit
precisely similar appearances ; that in some globules, for instance, it
will be observed that the contour is but slightly broken or indented ;
that in others the indentations of the surface are more considerable,
and the small spaces between them consequently more prominent;
and again, in other globules, and which are indeed by far the most
* Essai d'Hemalogie Pathologique, par G. Andral, page 23.
THE BLOOD. 139
numerous, it will be obvious that the whole surface has become dis-
tinctly tuberculated, each tubercle, of which there are several to each
globule, appearing to be of a spherical form, and resembling a minute
bubble of some gas, probably of oxygen, or carbon, according as the
blood is arterial or venous. That they are really of a gaseous nature
is proved, I think, by the fact of their gradual formation as well as
dissipation. M. Andral states, that in blood which has been deprived
of its fibrin, the corpuscles never exhibit the peculiar granulated or
tuberculated aspect which we have described ; and this fact he adduces
in support of the opinion entertained by him, that this peculiar con-
dition of the globules is due to the accumulation on their surface of
the molecules derived from the fibrin.
Mr. John Quekett is also of the opinion that this peculiar condition
of the blood globules of which we have been speaking, is occasioned
by the adherence to their edges of granules which he considers to be
derived from the interior of the corpuscles themselves. See "Observ-
ations on the Blood Discs and their Contents," Microscopic Journal,
vol. i. p. 65. For further observations on this granulated appearance
of the corpuscles, see Part I. p. 31.
MODIFICATIONS THE RESULTS OF DECOMPOSITION OCCURRING IN BLOOD ABANDONED TO ITSELF
WITHOUT THE BODY.
In blood abandoned to itself, and exposed to atmospheric influences,
changes of form and appearance speedily begin to manifest themselves
in the red corpuscles. These changes occur in regular order; they
first become wrinkled, deformed, and tuberculated; they next lose
their flattened and disc-like shape, becoming globular and smooth;
their colouring matter escapes from them, and they present a livid
hue. In this condition they are with difficulty discoverable in the
blood ; finally, they dissolve, and all traces of them disappear. These
successive changes are all produced in the course of a very few hours :
the exact period, however, varies with the temperature of the atmos-
phere and actual condition of the blood when extracted from the system.
MODD7ICATIONS THE RESULTS OF DECOMPOSITION OCCURRING IN BLOOD WITHIN THE
BODY AFTER DEATH
The changes which we have described as occurring in blood
abandoned to itself without the system, take place likewise in the red
corpuscle of that which is contained within the body after death, and
this even with a greater degree of quickness than in the former case ;
140 ORGANIZED FLUIDS.
the time, however, bears a relation to atmospheric conditions, to
temperature, as well as, especially, to the nature of the malady to
which the patient has succumbed. If the affection which has occa-
sioned death be of a nature to exhaust profoundly the vital powers
— if it be a chronic disease of long duration, as a typhoid fever — the
period requisite for the production of these changes will be very
short; so brief, indeed, that the alterations may be detected in the
corpuscles almost immediately after the extinction of life. It is of
much importance that the changes resulting from decomposition, and
which occur in the dead body, should not be confounded with real
and pathological alterations of the red corpuscles.
CAUSES OF INFLAMMATION.
Exciting Cause.
The fact which has been alluded to in the preceding pages, of the
accumulation of the white and red corpuscles in the tongue and web of
the frog, as a consequence of the application of irritation, bears a close
relation to the phenomena of inflammation, and shows that the exciting
cause of inflammation, whatever it may be — such as a blow, exposure
to cold, burns, scalds, or the application of irritating substances —
acts usually through the medium of the nervous system, the impression
produced on it impinging upon the structures to which the ultimate
nervous nbrillee are distributed, viz: the vessels in the which a series of
results ensue which together constitute the condition of inflammation.
Proximate Cause.
When the white and the red corpuscles of the blood accumulate
in the capillaries of a part in normal quantity, those vessels may be
considered to be in a state of "vital turgescence ;" when, however, they
are present in those vessels in abnormal proportion, then the capilla-
ries may be said to be in a state of "inflammatory turgescence."
Now, the term "congestion" indicates a condition of the vessels
intermediate between vital and inflammatory turgescence, and which
may be denominated " congestive turgescence."
In vital turgescence, a phrase which indicates the condition of the
vessels in a state of normal nutrition, the capillaries are slightly
increased in calibre, and are pervaded by an unusual, though perfectly
normal number of corpuscles, both red and white, but especially of
the latter, some of which adhere to the walls of the vessels.
THE BLOOD. 141
In congestive turgescence, or in congestion, the calibre of the
capillaries is more considerably increased in size, and a greater and
abnormal number of white and red corpuscles, especially the former,
are collected in the vessels. These corpuscles, if the turgescence ter-
minates in resolution without advancing to the condition of inflamma-
tion, do not undergo any structural changes, but enter again into the
circulation, their removal being determined by the discontinuance of
the exciting cause, and by the vis a tergo of the circulation, which
drives the corpuscles onward.
Lastly, in inflammatory turgescence, the diameter is very con-
siderably enlarged, and their interior is filled with a very greatly
increased and abnormal quantity of white and red corpuscles, these
accumulating to such an extent as either to seriously obstruct, or
altogether destroy, the circulation in those vessels. This condition
of the vessels is always accompanied by certain structural alterations,
which effect not merely the corpuscles themselves, but also the vessels
and parts adjacent to them ; these alterations being merely attributable
to the impediment presented to the onward progress of the blood in
the capillaries by the accumulation in them of the blood corpuscles.
We now know that the proximate cause of inflammation consists
in an abnormal accumulation of the corpuscles of the blood in the
minute capillary vessels, and which accumulation we perceive must
inevitably impede the function of the part in which the vessels are
thus surcharged, alter its structure, and finally tend to a sympathetic
disturbance of the entire economy. For this discovery we are
indebted to the microscope. It will thus be seen that some of the
ancient hypotheses in reference to the proximate cause of inflammation
were not so very far wrong, and that most of them recognise the
fact, that it is the capillary vessels and blood corpuscles which are
mainly concerned in the production of the phenomena of inflammation.
Finally, inflammation may, like congestion, terminate in resolution;
but, unlike congestion, it always leaves permanent traces of its
visitation, the resolution being but incomplete. It may terminate,
also, in "hepatization," or in "purulent infiltration." The fibrin of
the blood is the chief agent in producing the consolidation of the
structure known by the term hepatization, while it is the white cor-
puscles analogous to those of the blood, as will be seen hereafter, that
give rise to the purulent formation.
142 ORGANIZED FLUIDS.
PATHOLOGY OF THE BLOOD.
We now come to the consideration of the most important division
of our Chapter upon the Blood, viz: that which treats of the patho-
logical changes which that fluid undergoes, and a full and clear
understanding of which is so necessary to the safe and successful
treatment of disease.
These pathological alterations are numerous, and engage not
merely the solid constituents of the blood, the white and red corpus-
cles, but also its fluid elements, the fibrin and the albumen; the
abnormal conditions of each of which principles of the blood we shall
find to be accompanied by a distinct train of morbid phenomena.
It may be- said that the fibrin and the albumen being entirely of a
fluid nature, and not holding solid particles of any magnitude in
suspension, they ought not to be considered in a work devoted to
microscopic anatomy. We shall find, however, that these several
constituents of the blood are so intimately associated, that, in order
to understand any one of them fully, it is necessary that we should
possess a knowledge of the others also, and therefore I consider that
their discussion comes within the legitimate scope of this work.
For much of our knowledge of the pathology of the blood we are
indebted to the united researches of MM. Andral and Gavarret, to
whose valuable essay we shall have occasion hereinafter to make
frequent reference.
Pathology of the Red Corpuscles of the Blood.
The scale of the red corpuscles of the blood, relative to that of the
other elements, varies considerably, even in states of health. The
mean proportion of red corpuscles is estimated by MM. Andral and
Gavarret at 127 in every thousand parts of the vital fluid. This
scale may, however, be elevated to 140, or depressed to 110; the
variations in the quantity of the red globules within these limits being
compatible, however, with a physiological or healthy condition of the
blood, although the higher scale, 140, is allied to a state of plethora,
while the lower, 110, borders upon the opposite state, of anaemia, and
both of which may be regarded, if not as diseases in themselves, at
least as powerful, auxiliary, and predisposing causes of many morbid
conditions of the system.
THE BLOOD. 143
Increase in the Number of the Red Corpuscles. — Plethora.
An increase in the number of the red corpuscles of the blood exists
in that condition of the system which has been denominated the
plethoric, and which increase constitutes its chief element. The
authors already cited found the mean proportion of the red globules
in the thirty-one cases in which the blood was submitted to examin-
ation, to be in every thousand parts 141 ; the minimum 131, and the
maximum 154. With this increase in the number of the red cor-
puscles, it was not found that any other element of the blood had
become either augmented or diminished.
The symptoms which indicate the existence of plethora, whether
they be organic, or functional and mental, all admit of a ready and
satisfactory explanation by a reference to the increased quantity of
the red corpuscles.
The existence of a state of plethora implies high vital powers ;
there seems to be in the plethoric, as it were a super-abundance of
life, and which is imparted to all the parts and organs of the system
alike. The plethoric diathesis would appear to be more frequently
hereditary than acquired, and no degree of high and nutritious feeding
will induce it in the system of some persons, although an opposite or
anaemic state may be produced in all by the abstraction of a proper
quantity of suitable nourishment.
The general symptoms which characterize the plethoric diathesis,
are a well-developed muscular system, voluminous thorax, a deep-
coloured skin, and a ruddy complexion; coinciding with these
physical and outward appearances, we find much functional activity
to exist, the respiration is free and unembarrassed, the digestion quick
and active, the pulse is full and strong, and the motions of the body
are performed with celerity and power. This functional activity
appertains also to the operations and emotions of the mind; the
plethoric is quick in thought, hasty and violent in temper.
The injected skin, the brilliant complexion, are to be explained by
reference to the increased quantity of the red corpuscles which cir-
culate in the blood, and which alone are the seat of colour, while the
great organic development and the functional and mental activity
depend partially upon the greater amount of oxygen of which the
blood corpuscles are the carriers to all parts of the system, and which
is so essential to the vigorous performance of the vital processes and
manifestations.
144
ORGANIZED FLUIDS.
The characters exhibited by blood which has been withdrawn from
the system are likewise consistently explained by reference to the
augmented quantity of the red blood corpuscles ; thus the blood in
plethora, immediately on its abstraction, is observed to be of a deeper
colour, and the clot formed subsequently by its coagulation of a larger
size ; this, although voluminous, is of mean density, and never exhibits
the buffy coat, which circumstances are accounted for by the fact
that, as already remarked, in the blood of plethoric persons there
exists necessarily no excess of fibrin.
Accompanying the plethoric condition, and dependent upon it, we
have frequently a number of grave pathological manifestations, apo-
plexies, haemorrhages, congestions, vertigos, noises in the ears, and
flashes of light before the eyes; all of which are most generally greatly
relieved by venesection, which withdraws from the system a portion
of the super-abundant red blood corpuscles.
Decrease in the Number of the Red Corpuscles. — Ancemia.
The term anaemia indicates a state of the system the very reverse
of that which obtains in plethora: in it the red blood corpuscles,
instead of being in excess, are greatly below the physiological stand-
ard. The authors quoted found, in sixteen cases of commencing
anaemia, the mean of the red globular element of the blood to be 109;
and in twenty-four examples of confirmed anaemia, 65; that is, almost
one-half less than the standard which belongs to health. In one case
of anaemia in the human subject, M. Andral found the scale to
descend so low as 28 ; a depression which one would scarcely suppose
to be compatible with life.
In spontaneous anaemia it is stated, that it is the globules alone
which are affected, and that in it, as in plethora, the other elements
of the blood undergo neither augmentation nor diminution ; in acci-
dental anaemia, however, resulting from direct losses of the vital
fluid, the normal standard is of course disturbed; for in haemorrhages,
and especially in first bleedings, it is chiefly the globules which escape,
and this would lead to the relatively higher scale for the fibrin.
As anaemia depends upon a condition of the blood the very opposite
of that which exists in plethora, the symptoms also in these two
constitutional conditions are the reverse of each other; instead of
the vascular and injected skin, we find it to be livid and exsanguine,
these appearances extending also to the mucous membranes; in
THE BLOOD. 145
place of the accelerated functions, we notice that the vital actions
are sluggishly performed, and that the mental powers are feeble.
The blood abstracted from the system exhibits a paler tint than is
usual, and the clot is small, and floats in the midst of the serum,
which is very abundant; small, however, as the crassamentum is,
it is yet of considerable density, as might be expected from the
remark which has already been made, viz: that the fibrin exists in its
normal proportion, and therefore is in excess over the globular
element of the blood which is deficient; it is for the same reason
also that we frequently notice upon the surface of the clot the buffy
coat ; the density of the clot, and of the crust which covers it, are so
much the more marked as the anaemia is considerable.
The existence of the miscalled inflammatory crust in anaemic states
has long been known, although not satisfactorily accounted for.
The pathological disorders to which anaemia gives origin are
numerous : the general debility, the disordered digestion, the difficult
respiration, the palpitations of the heart, the faintings, are well
remembered.
There is a state of the system, well described by Andral, which
stimulates plethora, but which is really allied to anaemia, and to
which the term false plethora might be given; in this we have the
injected skin and many other indications of plethora; it is to be
diagonosed, however, by means of the constitutional disturbances
which coincide with those of ordinary anaemia.
It is in anaemic conditions of the system that we detect the remark-
able bruit de soufflet, in reference to which Andral in his essay on
the blood has instituted some useful researches, the chief result of
which is the establishment of the fact, that the intensity and persistence
of the bruit is in exact proportion to the severity of the anaemia.
In pregnancy we have a slight example of an anaemic condition of
the blood, and in chlorosis we see anaemia to prevail with various
degrees of severity. In phthisis the scale of the red corpuscles is
likewise much reduced, but not to the extent to which its reduction
is witnessed in chlorosis ; and this is the more remarkable from the
circumstance that in the former disease it is those organs which are
affected, between which and the red corpuscles a close connexion
exists. In cancer also the number of the blood corpuscles is
reduced: in phthisis the diminution precedes and accompanies
the whole course of the affection, while in cancer it occurs only at
an advanced period of the disease, and arises principally from the
10
146 ORGANIZED FLUIDS.
continual losses of blood to which cancerous patients are so subject.
In disordered states of the system, purely nervous, we find also the
red element of the blood to be deficient. The scale of the red globules
in a number of cases in which the blood of phthisical patients was
submitted to examination oscillated between 80 and 100.
Increase in the Number of the Red Corpuscles under the Influence
of Recovery and of certain Medicinal Agents.
Under the influence of recovery the red blood corpuscles increase
in number, and have a tendency to attain to their physiological
standard, which, when reached, they may even exceed, until at length
they mount up to the scale which denotes the existence of the
plethoric condition.
Certain medicinal substances exhibit likewise much influence in
increasing the number of the red corpuscles; of these the most
remarkable is iron, under the effect of which remedy the pale com-
plexion of the chlorotic will be seen gradually to acquire the tone and
colour indicative of health and strength.
Effect of Disease upon the White Corpuscles.
The white corpuscles of the blood have not hitherto received that
amount of attention which has been bestowed by so many observers
upon their associates the red corpuscles ; indeed, it is only in these
latter times that their investigation has been pursued with that
degree of care which, from their importance, they so well merit, and
observations are still wanting upon their condition in states of disease.
It has already been remarked that an increase in their number has
been frequently observed to occur in various diseases, and especially
in such as are accompanied by suppuration and great exhaustion of
the vital powers. Of the precise cause of this increase, no very
satisfactory explanation has been offered, and the following attempt
at an explanation is presented to the consideration of the reader with
much hesitation. In most serious disorders, the function of nutrition
and assimilation is more or less impeded. Now, supposing that these
white corpuscles are essentially connected with nutrition, and that
while the cause which determines their formation still continues
in operation, that which regulates their assimilation is suspended,
there would result, as an inevitable consequence, an accumulation of
the white corpuscles in the blood.
THE BLOOD. 147
Deficiency of Fibrin in Fevers, as in Typhus, Small-pox, Scarlatina,
Measles.
The important researches of MM. Andral and Gavarret establish
the fact, that, in that much-debated class of maladies, fevers, there
is a deficiency in the blood of its spontaneously coagulable element,
the fibrin. In the Essai d 'Hematologic no scale of the diminution in
the amount of fibrin is given; it is shown, however, that in some
fevers, and especially in the commencement, the deficiency of fibrin
may be but small; and that in others, particularly when symptoms of
putridity have manifested themselves, and which may ultimately
complicate all fevers, the loss of fibrin is considerable, and further
that the intensity of symptoms is in direct relation to this loss, being
great when the diminution of fibrin is also great.
It is not to be understood, however, that the deficiency of fibrin
constitutes the essence or real and specific cause of fever; for this
we must look to some other agent or fact, probably to the contami-
nation of the general mass of the blood by the imbibition of some
deleterious and subtle miasma. That the deficiency in the amount
of fibrin is not the cause of fevers, we find to be proved by the facts
that this class of maladies attacks persons of every possible variety
of habit and constitution, and in many of whom, at the onset of the
disorder, no deficiency of fibrin can be detected; and the same view
is likewise confirmed by the circumstance which must have attracted
the attention of every physician, viz : that the primary condition and
inherent powers of the system determine and control but to a com-
paratively slight extent the course which the malady may take, and
which course seems to be dependent upon the nature and quality of
the infecting agent itself. The inference, then, which may be derived
from the fact that a deficiency of fibrin exists in the blood of persons
afflicted with fever, is, that the tendency of the cause of fever, a
miasma, or whatever else it may be, is to occasion a depreciation of
the physiological standard of the fibrin in the blood, and not that the
deficiency is in itself the exciting cause of fever.
Between this diminution in the normal proportion of the fibrin and
the various hemorrhages, which are so often observed to complicate
fevers of all kinds, a corelation doubtless exists, although the precise
manner in which this deficiency leads to such a frequent recurrence
of hemorrhage is not clearly understood, and the only way in which
148 ORGANIZED FLUIDS.
this can be explained is by the supposition that in fevers from the
cause assigned, viz : the small quantity of fibrin, the solids generally,
and the blood-vessels in particular, lose a portion of their solidity, and
readily give way to the force of the fluid contained within them.
The hemorrhages referred to are frequently observed in small-pox,
in which the blood is effused into the pustules; in scarlatina, in which
fluxes take place from various parts of the body; and in typhus, in
which we- have frequent buccal hemorrhages, and the formation of
petechiae.
Cotemporaneous with this diminution in the amount of fibrin, we
do not find that any other element of the blood is constantly affected,
although it occasionally happens that the red globules are in excess.
The clot in typhus, in which, of course, the deficiency of fibrin is
considerable, is large, filling almost the entire of the vessel which con-
tains it; is soft, being readily broken up on the slightest touch; it is
flat, and ill-defined, and the serum in which it floats is of a reddish
colour.
The flat form and softness of the clot is to be explained by reference
to the diminished amount of fibrin, while its great size is accounted
for by the imperfect expression of the serum from the crassamentum,
as well by the fact that the red corpuscular element of the blood exists
usually in its normal proportion, and is not unfrequently found to be
even in excess.
The important distinction which exists between symptomatic or
organic fevers, and idiopathic, or non-organic fevers, is very essential
to be borne in mind, for in the former no such deficiency of the fibrin
exists as we have seen to belong to the latter; the blood in inflamma-
tory affections, as will be shown hereafter, exhibiting a state of its
spontaneously coagulable element the very reverse of that which
belongs to the blood of idiopathic febrile disorders. It must also be
recollected, that an idiopathic fever may, during its progress, become
complicated with organic lesion, a circumstance which would affect
materially the amount of fibrin in the blood, its effect being to increase
the proportion of that constituent.
Increase in the Amount of Fibrin in Inflammatory Affections, as in
Pneumonia, Pleuritis, Peritonitis, Acute Rheumatism, SfC.
While in the class of febrile disorders, of which we have just spoken,
a deficiency of the fibrin in the blood exists, in another series of
affections, the inflammatory, this element is found to be in excess
THE BLOOD. 149
To constitute an inflammation, however, two "concurrent circum-
stances are required; it is not alone necessary that the proportion of
the fibrin should be increased, but also that an organic lesion should
have occurred, these two pathological alterations bearing a close and
constant relation with each other.
Since, then, the spontaneously coagulable element of the blood in
the one class of disorders, viz : fevers, is deficient, while in the other
class, inflammations, it is super-abundant, it follows that the specific
cause which gives origin to these two orders of maladies operates in
two opposite directions; its tendency in the one being to diminish,
and in the other to augment the quantity of fibrin.
The law of the increase in the quantity of fibrin in inflammatory
disorders manifests itself under very remarkable circumstances; such,
indeed, as one would imagine to be but little favourable to its mani-
festation : thus, in the case of an inflammation supervening on typhus,
in which we have seen that the normal scale of fibrin undergoes a
depression, a disposition to the augmentation of that scale will become
apparent. In the example of typhus complicated with local lesion, we
have two forces in operation; the tendency of one of which is to
diminish the amount of fibrin, and of the other to increase that amount;
and the result of which forces operating at the same time is the pro-
duction of a mean effect.
The proportion of fibrin in man in a state of health is estimated at
3 parts in every 1000 of the blood. In a case of inflammation occur-
ring in the course of typhus, the scale was found to be h\ in persons
affected with chlorosis, in which we have seen that it is the globular
element of the blood which is deficient, and attacked with capillary
bronchitis, acute articular rheumatism, erysipelas, and pneumonia,
the proportion varied from 6 to 7 and 8; in acute inflammations
occurring in healthy individuals, it oscillated between 6 and 8; and
in a less number of cases, between 7 and 10. The highest scale
recorded by M. Andral is 10; and this was met with only in pneu-
monia, and acute rheumatism, while the lowest was only 4 : this
scale borders upon that which is regarded as normal, and is encoun-
tered only in sub-acute inflammations.
It is not merely, however, in pure and extensive cases of inflamma-
tion that the proportion of fibrin in the blood becomes augmented,
for we find it also increased in every organic affection which is
accompanied by even a slight degree of inflammation : thus in phthisis,
at the period of the elimination of the tubercle, as well as in cancer,
150 ORGANIZED FLUIDS.
in which there is inflammation of those portions of the organs, the
seat of the disease which immediately surround the tuberculous, or
cancerous deposit, we have also an increased amount of fibrin in
the blood. This increase, even in the last periods of the disorder
in phthisis, rarely exceeds 5 parts in the 1000. The blood in con-
sumption exhibits then not merely an excess of fibrin, but also a
depreciation in the proportion of its red element to the extent shown
under the heading AncBmia.
There is one condition of the system compatible with a state of
health, under which also the proportion of the fibrin in the blood
is augmented, and that is gestation. It is stated, however, by
M. Andral, that this increase manifests itself only in the three last
months of pregnancy, previously to which the scale of the fibrin is
found to be slightly depreciated. This augmentation goes on increas-
ing from the sixth to the ninth month, and is greatest at the comple-
tion of the term of utero-gestation, which fact offers a satisfactory
explanation of the reason of the liability to inflammatory attacks on
the part of women recently delivered. The condition of the blood,
therefore, in the last periods of pregnancy is allied to that state of the
vital fluid which is especially indicative of the existence in the system
of an inflammation.
The characters presented by the clot in inflammation are almost
the reverse of those which distinguish it in fevers. It is of moderate
size, of firm texture, frequently cupped, and its surface usually covered
with the buffy coating of a variable thickness. The theory of the
formation of this peculiar layer has already been entered into, and
the various circumstances under which it has been encountered have
now been noticed ; we have seen that it occurs in two very different
states of the system, that it is present on the clot of blood abstracted
in ansemic conditions, as well as on that formed in blood withdrawn
in inflammatory states ; in the first of these there is, in comparison
with the red corpuscles, a relative increase in the proportion of the
fibrin, and in the second, a positive augmentation of that important
element of the blood.
The fact of the existence of a super-abundance of fibrin in the blood
in inflammatory states may be in some measure inferred from the
circumstance of the escape in inflammation of a portion of its fibrin, and
which doubtless is attended with a certain degree of relief to the organ
affected. In many cases, however, it is not alone the fibrin which
escapes, and which is liable to become organized, but also the other
THE BLOOD. 151
constituents of the blood, its red and white corpuscular element, (the
latter probably constituting the pus which in certain severe cases is
met with,) and the serum : these constituents, however, are not sus-
ceptible of organization, and are, where recovery takes place, removed
from the situation of their effusion by absorption.
The discovery of the fact, that in inflammatory disorders an excess
of fibrin is formed, explains the exact manner in which blood-letting
proves so serviceable, viz : by removing from the system directly a por-
tion of its super- abundant fibrin; so powerful, however, is the cause
which determines the formation of this excess of fibrin, that in spite
of the most energetic and frequent use of the lancet, the scale of that
element of the blood will frequently, and indeed does generally, ascend.
Condition of the Blood in Hemorrhages.
Reference has been made to the frequent occurrence of hemorr-
hages in two very distinct classes of disorders, the plethoric and the
febrile. In the first, we have seen that it is the red element of the
blood which is absolutely in excess over the other constituents of that
fluid, while, in the second, it is the fibrin which is deficient, the
globules being unaffected, and existing usually in their normal pro-
portion. Thus, relatively to the fibrin in both series of affections, the
globules are always in excess, in reference to the first series, the pleth-
oric, being absolutely so, and to the latter, relatively super-abundant.
While it is this excess of the red globules which probably deter-
mines the occurrence of hemorrhages, the nature and degree of these
losses of blood are modified by the amount of fibrin which that fluid
contains. Thus, the character of the hemorrhages occurring in
plethoric individuals is very different from that encountered in persons
labouring under fever in most of its forms ; in the first, we have
copious epistaxes and the effusion of blood into the substance of the
brain, constituting sanguineous apoplexy; in the second, almost any
tissue of the body may be the seat of the effusion ; the blood may escape
from the nose, the gums, the throat, or the bowels, or it may be
poured out beneath the skin in patches, constituting petechiae, which
we meet with so frequently in severe cases of typhus, and in scurvy.
The hemorrhages to which the plethoric are liable are for the most
part salutary, while those which take place in fevers are as generally
prejudicial. The treatment to be adopted in the two cases is very
different ; in the one, it may be necessary to have recourse to vene-
section, with the view of lessening the scale of the red globules, and
152 ORGANIZED FLUIDS.
in the otner, such a mode of proceeding would in all probability be
fatal, the object in it being to restore to the blood its normal proportion
of fibrin.
The distinction which has here been dwelt upon between the
hemorrhages to which the plethoric are exposed, and those to which
the system is obnoxious in febrile disorders at an advanced period of
their attack, corresponds with the division of hemorrhages into active
and passive ; the former, or sthenic type, denoting the active, and the
latter, or asthenic, the passive hemorrhages.
In disorders in which usually we have no excess of the red globules,
but in which the fibrin invariably exceeds its usual quantity, as the
inflammatory, and in affections in which the red element is constantly
deficient, but in which the red fibrin retains its proper proportion, as
in anaemic states, and especially chlorosis, we find that hemorrhages
are of very rare occurrence, and hence again we are led to recognise
the accuracy of the statement, that the essential conditions for the
occurrence of hemorrhages are an excess of the red corpuscles, as
well as in certain cases a deficiency of the spontaneously coagulable
element of the bloed, viz : the fibrin.
Between the condition of the blood, in which there is a deficiency
of fibrin, as in most fevers, and that state of the system which occupied
so much of the attention of the ancient humeral pathologist, and which
has been denominated the putrid, an exact identity exists, and the
gresrter the depression in the scale of the fibrin, the more manifest
does the putridity become. While the blood is still circulating within
its vessels, we can scarcely conceive of its becoming putrid ; never-
theless, so great in some cases is the deficiency of fibrin, and so
proportionate the consequent tendency to putridity, that even during
life certain symptoms indicative of this condition become manifest, as
the extreme prostration of the strength, the foetor which belongs to all
the excretions, and the vital principle having escaped, the external
signs of decomposition almost immediately appear.
The characters of the blood in hemorrhages scarcely differ from
those which we have pointed out as belonging to it in fevers ; from
the small quantity of fibrin, and the excess of red globules, we find
that the clot is large, ill-formed, very soft, and never covered with the
buffy coating, and that finally, in a very short time, it undergoes
almost entire dissolution, the only trace of solid matter in the blood
consisting of a few shreds of fibrin.
There is one disease, viz: scurvy, in which a condition of the
THE BLOOD. ] 53
blood, as regards its fibrin, exists analogous to that which character-
izes fevers, and in which also the same tendency to repeated hemorr-
hages and to the formation of petechiae belongs, as is witnessed in fevers.
It is a question for consideration whether the deficiency of the
fibrin referred to is the real cause of the proneness of the blood to
decomposition and dissolution; and whether, if this be the case, there
is not some other prior cause which leads to and regulates the extent
of the diminution of the physiological standard of the fibrin.
The experiments of Magendie show that the mixture of certain
alkaline substances with the blood not merely preserve it in a fluid state,
but restore it to the fluid form, even after it has once coagulated. M.
Magendie injected into the veins of living animals a certain quantity
of a concentrated solution of the sub-carbonate of soda, and found that
in the dead bodies of these animals the blood was almost entirely in a
fluid state, and that even during life they presented many of the
symptoms which are acknowledged to denote a state of dissolution of
the blood.
The alkaline condition of the blood in scurvy, in which the prone-
ness to hemorrhage is so great, is well known.
A fluid state of the blood is said to exist in those who have died
from the bite of serpents, and it is most probable that in like manner
the effect of the imbibition of a poisonous miasma is to cause the
blood to retain its fluidity.
The deplorable effects which sometimes ensue from a dissection-
wound are most probably due to the entrance into the blood of a
poisonous matter, and in fatal cases we have all the signs indicative
of a dissolution of the blood.
It is likewise asserted, that any violent impression made on the
nervous system, either through the influence of some strong moral
emotion, or as the result of a blow, especially on the pit of the stomach,
an electric shock, as of lightning, retards, or altogether prevents, the
coagulation of the blood, while at the same time it destroys life. That
the same effect is likewise produced, though in a manner less obvious
and less sudden, by the slow and continued operation of any cause
which depresses the power of the nervous influence, so as at length
to effect the health prejudicially, cannot be doubted.
The proneness of children to hemorrhages, their liability to febrile
disorders, and the difficulty of restraining the bleeding which flows
from any breach of continuity which the skin may have suffered,
especially that of a leech-bite, in infants, are well known. The state
154 ORGANIZED FLUIDS.
of the blood in children is not commented upon by the talented
authors to whom we have had such frequent occasion to refer in their
important pathological essay on the blood; it is most probable,
however, that while its globular element is somewhat in excess, that
in fibrin it is equally deficient.
With one other remark we will bring this short chapter on hemorr-
hage to a conclusion, and proceed in the next place to consider the
effect produced upon the economy by the deficiency of another element
of the blood. The statistical and historical details of epidemics clearly
prove that those dire forms of disease, of which extensive and alarm-
ing hemorrhages were such frequent complications, have in these
latter times become much more rare. This happy result is doubtless
due to the advances made in the arts and sciences, and to their more
extensive application in the improvement of the hygienic condition of
mankind.
Decrease in the Normal Proportion of Albumen.
It is now generally known, that the majority of cases of dropsy
depend upon a pathological alteration of some solid organ of the body,
as the heart and the liver; most persons are also aware of the fact
that other cases of dropsy occur, which do not arise from any such
morbid organic condition, but have their origin, according to MM.
Andral and Gavarret, in a pathological degeneration of one of the
elemental constituents of the blood.
In the dropsy which attends the advanced stages of the affection
known by the name of Bright's disease of the kidney, in that which
supervenes upon scarlatina, in hydropsies arising from insufficient and
improper diet, as well as in those which occasionally follow suddenly
suppressed perspiration, it has been observed that the urine is always
albuminous, and the writers just mentioned have ascertained the
existence of a fact which stands in close relation with the albuminous
excess in the urine in the instances enumerated, viz : that the blood
is itself in these cases, on the contrary, deficient in albumen. Trie
knowledge of these two facts, therefore, and the observation that their
occurrence is so generally associated with dropsical effusion, has led
MM. Andral and Gavarret to entertain the opinion that a close con-
nexion exists between the deficiency of albumen in the blood and
the forms of dropsy alluded to, and which is probably that of cause
and effect.
In speaking of non-organic dropsies it has, until recently, been con-
THE BLOOD. 155
ceived sufficient to say that they depended as a cause upon impover-
ishment of the blood ; but this expression we now know to be vague,
inasmuch as it does not convey any exact notion of the real changes
which the blood may have undergone: we have seen that the blood
may be rich in its red globules or in its fibrin, and also that it may be
poor in these elements in almost every proportion and degree. Let
us see whether a deficiency of either of the two constituents just
named predisposes to dropsies. In anaemic states, and in chlorosis
especially, we have an impoverished state of the blood, and in these
we know that it is the red corpuscles which are deficient; and yet
daily experience shows us that dropsy in such states, and particularly
in chlorosis, even in its most severe forms, is a very rare termination.
In febrile disorders again, we have, for the most part, an impoverished
condition of the blood, arising from the depression in the scale of the
fibrin, and yet of these we do not find dropsical effusion to be by any
means a frequent result.
It is not excess of water in the blood which gives rise to dropsy,
for, if that were the case, then would it frequently occur in the dis-
order to which we have referred, chlorosis, in which a greater
proportion of water than is ^normal exists in the blood.
The causes of impoverishment of the blood enumerated therefore
do not act as exciting causes of dropsy : there remains but one other
element of the blood, the albumen, for our consideration, and this we
have seen to be constantly deficient in the blood in certain forms of
dropsy, and we are therefore constrained to adopt the conclusion that
this depreciation in the scale of the albumen is intimately associated
with the occurrence of those forms.
It does not appear, according to M. Andral, that the albumen can
undergo a spontaneous depreciation in the blood, similar to that of which
we have seen that the red globules and the fibrin are susceptible ; this,
if correct, is very remarkable, and hence it would follow that when-
ever a deficiency of the albumen of the blood exists, invariably, at the
same time, the urine would be found to be albuminous, provided
always that no dropsical effusion existed, the effect of some organic
malady.
In most organic dropsies the diseased organs act as exciting causes
of the serous effusion by the mechanical impediment which their altered
structure and enlarged size present to the circulation in the vessels,
and which, therefore, relieve themselves by permitting the escape of
a portion of their contents. In Bright's disease, although the kidney
156 0RGAE1ZED FLUIDS.
is affected, that organ does not concur in the formation of the dropsy,
except in a manner altogether indirect, and to such an extent only, as
that the pathological alteration which its substance undergoes is of
such a nature, as to afford greater facility to the passage of the
albumen through it.
The serosity effused in cases of dropsy is not identical in its con-
stitution with the serum of the blood ; it contains usually far less of
the inorganic constituents which are held in solution in healthy serum,
as well as a far less proportion of albumen, than that which belongs
to serum in its normal state. The physiological standard of the
albumen in the blood is eighty in every thousand parts ; in sixteen
cases in which the serous effusion was analyzed by M. Andral, the
scale was found to oscillate between 48 and 4, these two numbers
representing the highest and the lowest proportions. In six cases of
hydrocele, the amount of albumen was, as represented in the following
figures, 59, 55; two of 51 ; 49, 35. It should be remarked that none
of these analyses refer to cases of dropsy connected with excess of
albumen in the urine. It would be interesting to ascertain the amount
of the albuminous element contained in the serum effused in such cases.
MM. Andral and Gavarret state that they did not find that either
the cause of the hydropsy, or its seat, excited any influence over the
quantity of albumen of the effused serum; but they remarked that the
amount did in some degree depend upon the condition of the consti-
tution, and that the more robust its state, the greater the proportion
of the albumen: in this way the higher scale exhibited in the six cases
of hydrocele may be accounted for, their occurring in persons all of
whom were young and strong ; and thus, also, the great depression
of that scale may be explained in those whose constitutions have been
weakened by repeated tappings.
Two explanations may be given of the reason why blood less rich
than ordinary in albumen should give rise to serous effusion. The
first is, that the abstraction of the albumen may alter the density of the
serum, and thus permit more readily its escape through the walls of
the vessels; the second is, that blood deprived of its albumen becomes
less yielding, and so glides less easily along the walls of the capillary
vessels, thus occasioning in them an obstruction to the circulation
and consequent effusion of serum. Of these explanations, the former
is perhaps the more probable.
The proportion of water in all serous effusion is, of course, con-
siderable, and is greatest in those cases in which there is least
THE BLOOD. 157
albumen. The mean proportion of water in the serum of the blood
is 790 in 1-000 parts ; in the fluid of dropsies the highest scale hitherto
observed is 986, and the lowest 930.
The fluids effused in burns and scalds, and as the result of the
application of a blister, and which are always preceded by some
degree of inflammation, are also rich in albumen. The very curious
observation is made by M. Andral, that in cases where dropsical
effusion exists in more than one situation in the same individual, that
in each locality the fluid effused may exhibit a very different propor-
tion of albumen. Thus, in a woman attacked with an organic
affection of the heart, there were thirty parts of albumen in the fluid
of the pericardium, while there were but four parts in the serosity of
the cellular tissue of the inferior extremities.
In having thus ascertained the different modifications in quantity
which the three great elements of the blood may undergo — the globules,
the fibrin, and the albumen — it yet must be confessed that the patho-
logical history of the blood is still very far from being rendered com-
plete. It is more than probable that rigorous chemical analysis will
disclose the fact, that the several extractive as well as inorganic
substances which exist in the blood, vary greatly in amount in the
numerous disorders to which the human body is liable. From the
great quantity of these substances which are found in the urine, it
would appear that the grand purpose fulfilled in the economy by this
excretion is that of regulating their amount in the blood, and of
reducing it to a standard consistent with a physiological condition of
the system.
Into this branch of the pathology of the blood inquirers have as yet
scarcely entered ; and there can be no doubt but that investigations
instituted in this direction would be attended by the development of
many important facts.
Therapeutical Considerations.
The practical value to be attached to the various particulars related
in the preceding pages on the pathology of the blood, is so obvious
that it needs not to be illustrated at any great length.
The knowledge of the particular element of the blood which in any
state of the system or disease may be affected, inasmuch as it discloses
the chief cause of such condition or malady, furnishes the practitioner
with an unerring principle upon which the nature and the extent of
the treatment adopted should be founded. Hitherto, the chief guides
158 ORGANIZED FLUIDS.
in practice have been based upon experience and clinical observation;
both, doubtless, of high importance; but still not in many cases
sufficient to detect the cause of a malady, and therefore not in them-
selves equal to the determination of the exact line of treatment to be
pursued, or of the extent to which that line should be followed.
We are now not merely acquainted with the bare fact, derived
from experience, that in anaemic conditions of the system the different
preparations of iron are useful, but we have dived deeper into the
mysteries of organization, and we now know the reason why iron is
necessarily so beneficial in the disorders to which such a condition
of the system gives rise.
The precise objects to be held in view, in the employment of every
remedial appliance in the treatment of inflammatory affections and
fevers, we are now acquainted with ; and by our present knowledge we
can judge of the propriety and extent of usefulness of the various
plans of treatment which in times past have been had recourse to, or
which still continue to be applied; and we can detect the reason why
one particular mode of treatment should have been more successful
than another.
Becquerel and Rodier's Pathological Researches on the Blood.
MM. Becquerel and Rodier* have traversed the same ground as
MM. Andral and Gavarret in reference to the blood, which they have
examined both in health and disease.
These authors confirm many of the more important results obtained
by antecedent observers, but question the accuracy of some of those
results, and add new facts in relation to the normal and abnormal
composition of the blood.
The results which confirm those which had been previously obtained
are the following:
1. The augmentation of the fibrin in inflammations, the establish-
ment of which fact is especially due to MM. Andral and Gavarret.
2. The diminution of the globules in chlorosis, in the condition
denominated the anaemic, and under the influence of fasting; a fact
stated by M. Lecanu, and confirmed by MM. Andral and Gavarret.
3. The diminution of the globules from hemorrhages and anterior
bleedings ; a result which, signalized for the first time by MM. Prevost
* Gazette Medicate de Paris, 1844. "Recherches sur la Composition du Sang
dans l'etat de Sante et dans l'etat de Maladie."
THE BLOOD. 159
and Dumas, has been confirmed in the numerous analyses of MM.
Andral and Gavarret.
4. The little influence of bleedings upon the scale of the fibrin.
5. The diminution of the albumen in the malady of Bright, as
indicated by Gregory, Rostock, Christison, Andral and Gavarret.
Of the results which differ from, and perhaps invalidate those of
antecedent observers, the principal are —
1. That the scale TVVo> given as representing the mean of the
globules in a state of health, is too low, and is not the same in man
and in woman.
2. That the scale representing the fibrin as T/fj is too high.
3. That there is not alone in plethora an augmentation of the
globules, as signalized by M. Lecanu, and as has been admitted by
MM. Andral and Gavarret.
4. That the scale of the globules is not preserved in its normal
proportion in the majority of acute affections.
5. That the depression in the scale of the fibrin in severe fevers
is but little constant.
The more important of the new results are the following:
1. That the scale 141 expresses the mean number of the globules
in man in a state of health, and that of 127 represents the average in
woman.
2. That the ordinary scale of the fibrin is 2*2, and the mean 3.
3. That in plethora there is an augmentation of the quantity of
the mass of the blood.
4. That the influence of disease upon the composition of the
blood is to occasion from the commencement a diminution in the
proportion of the globules, and this diminution continuing during the
progress of the malady, ends in the production of the anaemic condition
of the system.
5. That there is an absolute excess of fibrin in many cases of
chlorosis and of pregnancy, and that its diminution is far less constant
than has been considered in fevers.
6. That the albumen of the blood diminishes under the influence
of illness; that it is more considerable in inflammations; and further,
that the diminution is in direct relation with the augmented amount
of fibrin, which it may be presumed is formed at the expense of the
albumen ; that there is not only a very great diminution of albumen
in the malady of Bright, but also in certain affections of the heart,
accompanied by dropsy, and in certain severe forms of puerperal fever.
160 ORGANIZED FLUIDS.
7. That the amount of cholesterine and of acid fats increases as
we advance in age ; but that this increase is not felt until from the
fortieth to the fiftieth year ; that it is also found in augmented quantities
in the blood in constipated states of the system, and in jaundice, with
retention of the bile and decoloration of the fasces.*
The Blood in the Menstrual Fluid.
The menstrual fluid contains all the elements of the blood, especially
the red and white corpuscles, and it is therefore in the same manner
as the blood itself susceptible of coagulation. In addition to the con-
stituents of the blood, we find the uterine discharge to be composed
of vaginal mucus, mixed up with numerous epithelial scales, which it
has acquired in its passage along the vagina.
Unlike, however, in one respect the blood itself, which in a state of
health is alkaline, the menstrual fluid is acid, its acidity arising from
its admixture with the vaginal secretion.
Transfusion of the Blood.
It has been stated, and the statement is most probably correct, that
between the size of the blood corpuscles and that of the capillaries
of the same animal, an exact relation exists, and it is by reference
to this fact that the fatal effects which have so often ensued, from the
transfusion of the blood of one animal into the vessels of another, have
been apparently so satisfactorily explained. The little vessels, it
has been said, are too small to admit the larger globules of the new
blood; a mechanical impediment is thus offered to the circulation of
the blood in the capillaries, which stagnates in them, giving rise to
constitutional disturbance, and ultimately to death. This explanation,
plausible as it appears, has been shown by recent experiments to be
erroneous, and that the true cause of the fatality which has so often
attended the operation of transfusion, depends upon the difference
which exists in the qualities of the fibrin in the blood of two different
animals, or even of two distinct individuals ; this is shown by the
fact that the transfusion of blood deprived of its fibrin is never followed
by the serious results to which reference has been made. Notwith-
standing this fact, it is yet very evident that if the blood of an animal,
the corpuscles of which are much larger than the human blood disc,
* The above remarks are abbreviated from an abstract of MM. Becquerel and
Rodier's work on the blood, by MM. Millor and Reiset, contained in the " Annuaim
de Chimie," for 1846.
THE BLOOD. 101
and at the same time are of a different form and structure — such as,
for instance, those of some birds — be introduced into the vessels of
man, a very serious and probably fatal mechanical impediment would
be presented to their circulation through the capillaries. Blood cor-
puscles' of a circular form, and but little larger than those of man,
might indeed make their way through the vessels in consequence of
the plastic nature of the globuline which composes them.
The new globules thrown into the system by the operation of
transfusion, although they would circulate for a time with the other
blood globules, would doubtless all become destroyed and removed in
the course of a few days, and this especially if the blood corpuscles
were different from those of the animal upon which the transfusion
had been practised.
The Blood in an Ecchymosis.
When a part is bruised to such an extent as to occasion the rup-
ture of the minute capillaries and vessels contained in it, blood is
effused, constituting an ecchymosis. The same effect sometimes takes
place, not as the result of the application of external violence, but
from disease, the solid tissues, and that of the vessels especially, giving
way through debility, and permitting the escape of their contents, as
occurs in malignant and putrid fevers, in Purpura Hemorrhagica,
in scurvy, and in bed-sores.
If a portion of the effused blood be removed from the bruise, and
examined microscopically, the globules will be observed to be wrinkled
and irregular in form ; corresponding with and depending upon internal
changes in the condition of the blood effused, and which are indicative
of the occurrence of decomposition, certain external appearances
will be noticed ; the skin will appear mottled, different hues of black,
green, and yellow being intermixed, and varying in intensity until
the period of their total disappearance.
The phenomena of decomposition precede the disappearance of
the red corpuscles which are removed from the seat of injury, and
are returned to the circulation in a state of solution. Now, were the
opinion true that the blood corpuscles are applied directly to the for-
mation of new tissue, a very different result to the decomposition and
solution of the globules, to which we have referred, would be antici-
pated, and we should expect to find that the extravasated blood had given
rise to an adventitious and organized product, an event to which
ecchvmoses never lead.
11
162 ORGANIZED FLUIDS.
The Effects of certain remedial Agents upon the Constitution and
Form of the Blood Corpuscle.
We have seen, in the remarks on the effects of reagents, that many
solutions and substances applied to the corpuscles, after their abstrac-
tion from the system, modify their form, appearance, and properties.
Thus we have seen that in water, as in any other analogous liquids
of less specific gravity than the serum of the blood, that the corpuscles
lose their normal form, and become circular, their colouring matter
passing at the same time into the fluid.
We have likewise. observed that in liquids of an opposite character,
and the density of which equals or exceeds that of the blood, their
form is preserved, and even rendered flatter than ordinary: thus,
their shape is well maintained or but slightly affected in the white of
egg, urine, the saliva, concentrated solutions of sugar, of the chlorides
of sodium, and of ammonium, and the carbonates of potassa and
ammonia.
The blood corpuscles likewise preserve their form in the solutions
of other substances, the density of which would not appear to be very
great, but which are possessed of very strong and decided properties :
thus, they maintain their shape well in a solution of iodine, and become
but slightly contracted in that of chloride of sodium; while, according
to Henle, the primitive flattened form of corpuscles, swollen by the
imbibition of water, may be restored to them by the application of
the concentrated saline solutions.
Nitric acid produces an irregular contraction of the corpuscles. It
has been remarked in like manner that a host of substances affect
the colour of the corpuscles.
But it is not alone the form and colour of the blood corpuscles
which are affected by the contact of reagents; their properties also
are modified by them.
Thus, the corpuscles to which iodine has been added are so hardened
by it, that they experience little or no change of form on the addition
of water.
The same is the case, according to Henle, after treatment by nitric
acid.
The acetic, and one or two other acids, it is known, dissolve the
corpuscles of the mammalia without residue, but leave almost unaf-
fected the granular nucleus contained in the red blood corpuscles of
oviparous vertebrata.
THE BLOOD. 163
The above are some of the more striking effects produced in the
form, colour, and constitution of the blood corpuscles out of the sys-
tem, on their treatment by reagents.
Now, there is evidence to show that blood corpuscles, while they
are circulating in the body, are likewise affected, although to an
extent less considerable, and therefore less appreciable, by substances
and solutions introduced into the system through the medium of the
lungs or of the stomach.
Thus, we know that the blood changes its colour in the lungs and
during its circulation through the capillaries, and that these changes
are dependent upon the relative amount of oxygen and of carbon
contained in the corpuscles.
Again, it has been asserted by Schultz, as already mentioned, that,
accompanying these alterations of colour, there are also changes of
form, the corpuscles becoming more or less circular in carbonic acid
and hydrogen gases, and flat in oxygen gas. This assertion I have
myself failed to verify.
It cannot be doubted, however, but that the form of the red blood
corpuscle must vary according to the variations of density experienced
by the liquor sanguinis, and further but little hesitation can be felt
in admitting that this alteration of density does really attend upon
particular conditions of the system ; thus, in inflammatory affections,
the liquor sanguinis is assuredly more dense than it is in states in
which an opposite condition of the blood exists, that in which the
watery element abounds.
After very copious imbibition of water, also, it can scarcely be
doubted but that the density of the blood is lessened, and that the red
corpuscles are modified in shape in consequence.
Thus much for colour and form ; let us see if we are acquainted
with any fact capable of proving that the constitution of red blood
corpuscles is also influenced by the introduction into the stomach of
remedial agents.
Schultz relates the fact that the corpuscles of the frog, in the
mouth of which during life iodine had been placed, resisted for a
longer time the action of water.* The truth of this most interesting
and important observation I have myself verified.
The blood corpuscles of a frog, which were subjected to the vapour
of iodine, underwent no appreciabe change of form in water for
nearly an hour during which they were observed, a time more than
* Das System der Circulation. Stuttgard, 1836, p. 19.
164 ORGANIZED FLUIDS.
sufficient to ensure the complete change of shape and subsequent
disintegration of the blood discs of a frog not similarly treated.
It may be observed that in the case related, starch failed to detect
the presence of iodine, although this was set free by previously dis-
solving the corpuscles by means of acetic acid.
After the relation of the above facts, it is evident that remedial
agents do affect in several important particulars the blood corpuscles
of the living animal, and it is further probable that a considerable
proportion of their remedial influence is dependent upon the nature
and extent of their power in modifying the red blood disc.
The Importance of a Microscopic Examination of the Blood in
Criminal Cases.
In criminal cases it is sometimes a matter of the highest importance
to the furtherance of the ends of justice, that the nature of certain
stains, observed on the clothes of an accused person, should be clearly
ascertained.
The fact usually to be determined is, whether the stains in question
are those of blood or not. Now, in the decision of this important
matter, the microscope comes to our aid in a manner the most deci-
sive and convincing.
If the stain be a blood stain, and if its examination be properly
conducted, the microscope will lead to the detection in it of the blood
corpuscles themselves, both white and red.
The inquiry having been proceeded with thus far, and the stain
having been proved to be one formed by blood, it still remains for
decision, whether the blood thus detected is human or not.
In the solution of this difficulty the microscope likewise affords
considerable assistance, and this of a kind which can be obtained in
no other way. Although by this instrument we are not able to assert
positively from an examination of the blood stain itself, free from
admixture with any other organic material, that the blood is really
human, we yet shall have it in our power very frequently to declare
the converse fact, viz : that a certain blood stain is constituted of
blood which is not human, a particular on the knowledge of which
the life of an accused individual might depend.
Thus, if we find that the blood globules are of a circular form, and
destitute of nuclei, we may safely conclude that they belong to
an animal of the class Mammalia, although, at the same time, we in
all probability should not be able to pronounce upon the name of the
THE BLOOD. 1G5
mammal itself; if, on the contrary, the blood corpuscles are elliptical,
and provided with a granular nucleus, we may be equally certain
that they do not appertain to that class, but either to the division of
birds, fishes, or reptiles.*
By the size also as well as the form of the corpuscles, some idea of
the animal from which the blood was derived might be formed ; and
if we cannot pronounce with certainty upon this, we shall at all
events, and at all times, be able to go the length of affording negative
evidence, and of asserting that the corpuscles do not represent the
blood of certain animals which might be named, and a knowledge of
which fact might prove of extreme importance.
To show the valuable nature of the evidence which it is in the
power of a medical man who makes a right use of the microscope
frequently to afford, in criminal inquiries, we will suppose the follow-
ing case:
A person is apprehended on the suspicion of having been concerned
in a murder. On his clothes are observed certain stains; upon these
he is questioned; he admits that they are blood stains, and states that
he had been engaged in killing a fowl, and that in this way his clothes
had acquired the marks. The stains are now submitted to micro-
scopic examination ; the blood of which they are constituted is found
to belong to an animal of the class Mammalia, and not to that of
Aves; discredit is thus thrown upon the party suspected, fresh
inquiries are instituted, fresh discoveries made, and the end of all is
the conviction of the accused of the crime imputed.
But a third question presents itself, to which it is very necessary
that a satisfactory reply should be made, viz : did the blood, of which
the stain is constituted, flow from a living or dead body? This query
we will proceed to answer.
If a vessel be opened during life, or even a few minutes after death,
the blood which issues from it in a fluid state will quickly become
solidified from the coagulation of the fibrin.
But if. on the other hand, a vessel be opened some hours after
death, the fluid blood which escapes will not solidify because it con-
tains no fibrin, this element of the blood having already become
coagulated in the vessels of the body in which it still remains.
Now, this act of the solidification of the fibrin is deemed by many
* The only animals of the class Mammalia which have blood corpuscles of an
elliptical form, are those of the order Camelidcc ; they are, however, very small, and
destitute of nuclei.
166 ORGANIZED FLUIDS.
to be a vital act, and to be the last manifestation of life on the part
of the blood.
It would appear, however, that the coagulation of the blood should
not be regarded as a vital act, seeing that blood which has been kept
fluid for some time by admixture with saline salts will coagulate when
largely diluted with water, and also, that blood which has been frozen
previous to coagulation will undergo the process of solidification after
it has been rendered fluid again by thawing.*
Presuming, then, that the coagulation of the blood is not an act of
vitality, the inference to be deduced from the presence of coagulated
fibrin in blood stains, in which the corpuscles may be detected, is
scarcely weakened thereby, since the finding of such fibrin in such a
situation, and in connexion with the blood corpuscles, scarcely admits
of a rational and probable explanation of its occurrence being given
apart from the idea that the blood had issued from a body either liv-
ing or but just dead, and in which coagulation of the fibrin in the
vessels had not occurred.
The blood stains, therefore, which contain coagulated fibrin in
them, it is but little doubtful, must have proceeded either from a liv-
ing individual, or from one but just dead ; while, on the contrary, it
is as little to be doubted, but that those stains which do not contain
solidified fibrin, must have emanated from a body dead some hours,
or from blood which had already been deprived of its fibrin.
From the disposition and form also of the blood spots, some idea
can be formed as to whether the blood had sprit out of a living body
or not.
A few observations may now be made, first, on the length of time
after the formation of blood stains at which the corpuscles can be
detected ; and second, on the best mode of proceeding in the exam-
ination of those stains.
From observations which I have made, it would not appear that it
is necessary that the blood stain should be recent. I am inclined to
think that the period scarcely admits of limitation.
Thus in blood stains six months old, I have observed the corpus-
cles presenting very nearly the form and appearance proper to them
when recently effused, and previous to their becoming dried up.
In the blood of the frog, six months after its abstraction from the
* Dr. Polli has related a case in which the complete coagulation of the blood did
not take place until fifteen days after its abstraction. — Gazzetta Medica di Milando,
1844. ■
THE BLOOD. 167
animal, I have observed the corpuscles, both red and white, and in
the former, the characteristic granular nuclei with so much clearness,
that it would have been an easy matter to have studied upon them
the development of blood corpuscles.
The observance of one precaution, at least, is necessary for the
successful exhibition of the microscopic characters of blood stains.
Thus, water should never be applied to them, nor indeed any other
fluid, the density of which is less than that of the serum of the blood,
for all such liquids will occasion the discharge of the colouring mat-
ter of the blood corpuscles and an alteration of their form ; thus the
circular but flattened corpuscles of the Mammalia will assume a glob-
ular shape, as will also the elliptical blood discs of birds, fishes, and
reptiles ; one of the greatest points of difference between the blood
corpuscles of the former and latter classes being thereby effaced.
Blood stains, therefore, should be moistened, previous to examina-
tion, with some fluid, the density of which nearly equals that of the
liquor sanguinis; and I have found the albumen of the egg to pre-
serve the form of the corpuscles excellently well.
Failing, however, in detecting the blood corpuscles, a result scarcely
to be anticipated, assistance may be derived from a toxicological
examination of the blood.
The only tests peculiar to the blood are those which have relation
to the haematine. This principle it would, however, be difficult to
obtain from blood stains in sufficient quantity for the purposes of
copious chemical analysis.
Nevertheless, corroborative evidence of the suspected character of
a stain might be obtained by its general chemical analysis, and which
should be treated as follows:
The stain should first be moistened with cold distilled water; as
much of the matter of it should then be removed as possible, and
placed in a test tube with an additional quantity of water. This
being agitated, the colouring material, if the stain be a blood stain,
will be dissolved by the water, imparting to it a pinkish colour, while,
provided the blood flowed from the body during life, or at all events
within a few minutes of decease, suspended in the liquid, will be seen
shreds of fibrin.
This solution, when heated to near the boiling point, will become
turbid, and deposit flakes of albumen.
The same thing will occur when it is treated with nitrate of silver
or bichloride of mercury.
168 ORGANIZED FLUIDS.
The addition of a strong acid or alkali turns the colouring matter
of a brown tint.
These results, however, are common to other mixtures of animal
substances in combination with colouring matter besides the blood,
and no one of them is perfectly characteristic.
It would therefore appear that the microscope is capable of reveal-
ing evidence much more satisfactory in reference to the nature of
blood stains, than that which it is possible to derive from chemical
examination.
Finally, it may be observed, that during the examination of blood
stains, other substances may be detected in connexion with them, the
presence of which would reveal not merely their nature, but also the
seat from which the blood forming them had flowed ; thus, some of the
various forms of epithelial cells and of hairs, may occasionally be
encountered in them.
We now bring to a conclusion this long article upon the grand for-
mative fluid of the system, the blood, and pass to the consideration of
other fluids of the economy, viz : pus and mucus.
THE BLOOD. 109
PREPARATION.
[Fresh blood may be examined by placing a very small quantity on a
plain glass slide, thinning it with a little serum, and quickly covering it with
a piece of thin glass. The object is then ready for examination, and will
require a power of 600 to 650 diameters, to well define its corpuscles. The
different reagents may then be introduced by means of a pipette : the most
striking in their effects, are water, acetic acid, nitric acid, and alcohol.
Perhaps the most marvellous sight that the microscopist can behold, is
that of the circulation of the blood. For this purpose, the frog is usually
selected, and instructions have already been given for preparing the tongue,
so as to show this phenomenon.
There are other portions of the frog in which the circulation may be
readily seen ; one of these is the transparent part of the web of the hind
feet. In this manipulation, the body of the frog is to be secured to the
frog-plate, by means of a narrow bandage or piece of tape. Those who
do not possess a frog-plate, may readily make one by taking a piece of thin
board about six inches long, and three inches wide; in this, a hole an inch
square is to be cut near one end. The frog, secured in the bag, is tied to
the solid part of the thin board, in such a manner that the web of the foot
may be brought over the hole. The foot is then stretched out to the utmost,
and fastened in this condition by means of strings tied to the toes, and
secured to small pegs, or tacks, driven in at the margin of the board.
Another method of securing the web in a state of tension, is by means of
pins run through the toes, and fastened to the board. The plate, when ready,
is placed upon the stage of the microscope, and the web may be examined
by means of a power from 50 to 100 diameters. Any very transparent
part may be examined with a much higher power, even to 670 diameters.
The web should be kept moist with clear water.
Mr. Quekett observes, (page 339) " A frog so mounted, is capable of exhibit-
ing many of the effects of inflammation ; if, for instance, a spot in the web
be touched with the point of a needle, or a small drop of alcohol, or other
stimulating fluid be placed upon it, the circulation will stop in that part for
a longer or shorter period, according to the amount of injury inflicted ; the
vessels in the neighbourhood will soon become turgid, and even sometimes be
entirely clogged up with blood; if no further stimulus be applied, they will
be seen to rid themselves of their contents as easily as they became full, and
after a time, the circulation will be restored in every part. For those who
are unacquainted with the parts which may be observed with the micro-
scope, in the foot of the frog, it may be as well here to state, that the
majority of vessels in which the blood is seen to circulate, are veins and
capillaries; the former may be known by their large size, and by the blood
moving in them from the free edge of the web towards the leg ; also, by their
170 ORGANIZED FLUIDS.
increase in diameter in the direction of the current ; the latter are much
smaller than the veins, and their size is nearly uniform ; the blood also cir-
culates in them more quickly. The arteries are known by their small size,
and by the great rapidity with which the blood flows in them ; they are far
less numerous than either of the other vessels, and, generally speaking, only
one can be recognised in the field of view at a time ; in consequence of
their being imbedded deeper in the tissues of the web than the other ves-
sels, the circulation cannot be so well defined as in the latter. The black
spots of peculiar shapes that occur in all parts of the web, are cells of pig-
ment, and the delicate hexagonal nucleated layer, which, with a power of
one hundred diameters, can be seen investing the upper surface of the web,
is tesselated epithelium."
If the lung or mesentery of the frog be desired for exhibition, and they
will both be found to display the most beautiful sight that can be conceived,
the following method must be adopted : The frog must be dipped in water,
at about 120° temperature; this heat will destroy muscular action, but will
not suspend the circulation. The animal is then to be opened, and the lungs
full of air will protrude ; one of these is bent over on a plain glass slide,
and may be then viewed with a low power. The mesentery may be dis-
sected out, and viewed in the same way.
When the tad-poles of the water-newt and frog can be found, and they
are abundant in the latter summer and early fall months, the tails of these
little creatures afford beautiful views of the circulation. No further prepa-
ration is necessary than enveloping their bodies in bibulous paper, leaving
their tails to project ; they are then placed on the stage of the microscope
in a watch-glass or live-box, and without any pain or injury to the animal,
may be observed for hours, by keeping the bibulous paper moistened with
water.
PEESEEYATION.
The blood corpuscles may be readily preserved for future examination,
by placing a small quantity of fresh blood on a plain glass slide, and rapidly
passing the slide backwards and forwards, so as to dry the blood as soon as
possible. The corpuscles will then be found to be but little altered in form ;
they are then to be covered with a piece of very thin glass, which must be
cemented down with gold size, taking care to paint on a very thin layer at
first, and a thicker one afterwards, when the first has become dry. Blood
corpuscles, so preserved, will keep for years. They may also be preserved
in the flat cell, with Goadby's A-2 solution, or in a weak solution of chromic
acid, care being taken that the cell be tightly sealed.
Specimens of the blood of many birds, fishes, reptiles, and mammalia,
may be readily procured, and when preserved in the manner already
described, will form objects of great interest.]
MUCUS. 171
ART. III.— MUCUS.
We have seen that the blood consists of two parts, the one fluid,
the liquor sanguinis, the other solid, the globules ; the same constitu-
tion belongs also to mucus as well as to some other of the animal
fluids, as, for example, pus and milk.
Mucous globules find their analogue in the white corpuscles of the
blood, while the fluid portion of mucus resembles closely the fibrin of
the blood, fibrillating or resolving itself into fibres in the same manner
as the fibrin. From this fact there can be no doubt but that the
transparent or fluid constituent of mucus is mainly composed of fibrin.
It is probable that the fluid portion is the only essential constituent
of mucus, and that the globules are connected with it merely in an
indirect and secondary manner, notwithstanding that their presence
is all but constant. The correctness of this view is in some measure
sustained by the fact, observed first by M. Donne, that the mucus
obtained from the neck of the uterus, in young girls, is invariably
free from corpuscles.
It is with the solid particles of the mucus that we shall be chiefly
occupied, for they more properly enter into the domain of the micro-
scope; the fluid element eludes to a great extent the power of this
instrument, and the detection of its properties enters principally into
the province of the chemist.
GENERAL CHARACTERS.
Healthy mucus, in its fluid state, is a transparent, viscid and jelly-
like substance, which does not readily become putrescent; in its dried
condition, it assumes a dark appearance, and a horny and semi-
opaqe texture ; in water it swells up, reacquiring most of the prop-
erties which characterized it when recent. It sometimes exhibits an
acid, and sometimes an alkaline reaction, according to the exact
structure of the mucous membrane by which the mucus is itself
secreted.
Mucous membranes, therefore, as might be inferred from the con-
cluding passage of the preceding paragraph, do not all present a
constitution precisely similar the one to the other ; and on their differ-
ences of organization a division of them into three classes may be
instituted, as has been pointed out by M. Donne.
172 ORGANIZED FLUIDS.
The first class of mucous membranes comprises those which are
contiguous to the outlets of the body, and which are to be regarded •
as extensions of the skin, participating in all its properties: thus, the
fluid secreted by this class of mucous membranes manifests, like that
of the skin, an acid reaction, and the same epithelium which invests
the latter belongs also to the former; in other respects the corres-
pondence is likewise exhibited, the membranes under consideration
manifest the same sensibility, the same freedom from hemorrhage,
which characterize the skin; they in like manner ulcerate less readily,
and are never furnished with the vibratile cilia which belong to the
second class of mucous membranes, viz : the true. This first-described
class of membranes may be denominated false mucous membranes;
and, as an example of it, the vagina may be cited.
The membranes which belong to the second class are situated
more internally than the last, and have scarcely any thing in common
with those of the first class : the mucus secreted by them constantly
exhibits an alkaline reaction, and the. epithelium which invests them
is of a totally different structure, the cells which constitute it being
cuneiform, and in some situations provided with numerous vibratile
cilia: the general properties of this class of membranes are also
opposed to those of the previous division: thus, they are but little
sensitive to the touch, are frequently the seat of hemorrhages, and
ulcerate with much facility. The membranes of this class are to be
considered as the true mucous membranes, and that which lines the
trachea and bronchi may be instanced as the type of this class.
The third class is more artificial than the two preceding ; the
membranes which it comprises exhibit in a greater or less degree
the characters of each of the divisions already described, between
which they are intermediate in situation, as in structure, participating
in the characters of the false or true mucous membranes more or less,
according to the preponderance of either of these classes. The
membranes of this division may be called mixed, and those of the
mouth and nose may be regarded as typical.
Now, however useful for the purposes of description the above
classification may be, it must still be remembered that it is, to a very
considerable degree, arbitrary ; the membranes which we have described
as false mucous membranes belong rather to the skin than to true
mucous structure, while the mixed membranes exhibit only the grad-
ual transition from the external skin to the internal true mucous
membrane: thus, strictly speaking, there is but one class of mucous
mucus. 1 73
membranes, and that the true. Corresponding with the differences
which have been pointed out as characteristic of the three classes of
mucous membranes, there are others appertaining to the mucus
secreted by each of these orders of membranes, and which arise from
their diversity of structure, and which serve to distinguish the mucus
of the one class from that of each of the other classes.
1st. The mucus proceeding from true mucous membranes is vis-
cous and alkaline, containing, imbedded in its substance, numerous
spherical, semi-transparent, and granular corpuscles of about the
2 2V0 °f an mcn m diameter (see Plate XL fig. 1),* having a some-
what broken outline, as well as occasionally epithelial cells more or
less cuneiform, and sometimes, provided with cilia. These corpus-
cles are for the most part nucleated, they are not at first soluble in
water, but swell up in that fluid to two or three times their former
dimensions (see Plate XI. fig. 3), and, like the white globules of the
blood, to which they bear the closest possible resemblance, they con-
tract somewhat under the influence of acetic acid, and are soluble in
a concentrated solution of ammonia.
2d. The mucus secreted by false mucous membranes, or those which
are analogous to the skin, although more or less thick, does not admit
of being drawn out into threads, is acid, and, in place of spherical
globules, contains numerous scales of epithelium, which differ from
true mucous globules in their much larger size, flattened form, and in
their irregular and very frequently oval outline: these scales, like the
true mucous corpuscles, are nucleated, and the nuclei comport them-
selves with chemical reagents, in the same manner as the globules of
mucus.
Example: — the mucus of the vagina. (See Plate XII. fig. 1.)
3d. The mucus proceeding from the mixed or transition membranes
is sometimes acid, sometimes alkaline, at others neutral, and contains
a mixture of true mucous corpuscles and epithelial scales, the relative
proportion of each of which varies according to the exact structure
of the membrane by which it is furnished. (See Plate XII. fig. 2.)
These divisions of the mucus into three different kinds, although to
some extent artificial, as already observed, are yet not without their
practical utility.
* A law having reference to size, and the importance of which will be hereaftef
demonstrated, may here he announced. It is that the several structures, especially
the corpuscular ones, entering into the composition of the animal organization, hear
a near relation of size the one to the other.
174 ORGANIZED FLUIDS.
The microscopical and chemical characters of mucus likewise vary
much, not merely according to the general organization of the mem-
brane by which it is secreted, but also in accordance with the condi-
tion of the membrane itself, with the degree of irritation or inflam-
mation to which it is subject, and with the precise nature of the
disorder by which it is affected ; thus, sometimes, the mucus secreted
by the lining membrane of the nose is thin and watery, the fluid
element being in excess, and at others it is thick and opaque, its solid
globular constituents super-abounding. Its colour also as well as its
consistence exhibits various modifications in pathological states,
being sometimes white, greenish or yellow.
The description of the different forms of epithelial cells alluded to,
and which are occasionally encountered in the mucus mixed up with
true mucous corpuscles, belongs not to the fluids, and will be given
in detail under the head of Epithelium, in that division of the work
which is devoted to the consideration of the solids of the human
body; the structure, form, size, properties and nature of the true
mucous corpuscles may here be described with advantage.
MUCOUS CORPUSCLES.
Structure. — The mucous corpuscles, which are colourless, and
mostly of a circular form, are each constituted of a nucleus, an envel-
ope, an intervening fluid substance, and numerous granules, which
are diffused generally throughout the entire of the corpuscles, being
contained within the cavity of the nucleus, in the space between this
and the outer envelope, and, lastly, in the substance of the envelope
itself; this arrangement imparting a granular texture to the entire
corpuscle. (See Plate XL)
The nucleus, like the corpuscle itself, is a circular body of about
one-third, or one-fourth its size : it sometimes occupies a central, but
very frequently an eccentric position in the mucous globule : it is not
at all times visible, although very generally so, without the addition
of reagents, the best being water and acetic acid.
The addition of water to mucous corpuscles discloses, in the
majority of them, but a single nucleus (see Plate XI. Jig. 3) ; in some,
however, two and even three or four nucleoli appear, these resulting
from the division of the substance of the single primary nucleus.
1 The effect of a weak solution of acetic acid is the same as that of
water, except that an additional number of corpuscles are seen after
its application to possess the divided nucleus, while in others the
mucus. 175
single nucleus is observed to be oval, and occasionally contracted in
the centre — this form being the transition one from the single to the
double nucleus. (See Plate XJ.fig. 4.)
If undiluted acetic acid be used, then all the corpuscles will present
a compound nucleus, consisting of two, three, four, or five nucleoli,
the usual number being two or three; the investing membrane at the
same time under its influence loses its granular aspect, and appears
transparent and smooth. (See Plate XI. fig. 5.)
The formation of these nucleoli maybe thus explained : — The effect
of acetic acid is to contract the entire corpuscle ; on the nucleus,
however, it would appear to operate with such force as to occasion
a complete division of its substance.
The divided nucleus has been observed by many observers in the
pus globule, but its occurrence in the mucous corpuscle has not been
generally noticed; this division of the nucleus has been considered to
constitute an exception to the law of the development of a cell around
a single nucleus ; whether it ought to be so regarded is doubtful, see-
ing that these multiplied nuclei are usually the result of the operation
of a powerful reagent, and are but rarely visible, unless as the conse-
quence of the application of some reagent.
Mr. Wharton Jones has endeavoured to meet this conceived
exception, by supposing that the nucleoli are all enclosed within the
membrane of the nucleus. I have myself, however, failed to detect
the existence of any envelope surrounding the nucleoli.
Form. — The form of the mucous corpuscle, although usually
spherical, is subject to considerable variety, this depending frequently
upon the density of the fluid in which it is immersed, but occasionally
also upon the amount of pressure to which it may be subjected.
Thus, in fluid which is very dense, the operation of exostosis is set
up between the corpuscle and the fluid medium which surrounds it,
whereby a portion of its contents passes into that medium, as a con-
sequence of which its investing membrane collapses, and exhibits a
variety of forms. (See Plate XI. fig. 2.)
Corpuscles thus affected nevertheless retain the power of reassuming
the form which properly belongs to them when they are immersed in
Water or any other liquid, the density of which is less than that of the
fluid contained within the cavity of the corpuscle itself. (See Plate
XL fig. 3.)
The form of the mucous corpuscle is also subject to alteration from
another cause, viz: pressure. Thus, it is often seen to be of an oval
176 ORGANIZED FLUIDS.
form in thick and tenacious mucus; this shape results from the pres-
sure exercised upon the corpuscles by the almost invisible fibres into
which the fluid part of mucus resolves itself, and which often become
drawn out in the adjustment of the mucus on the port-object of the
microscope. (See Plate XII. Jig. 3.)
The oval shape thus impressed upon it is permanent, because the
pressure of the fibres of the solid mucus ceases not to act: if the
pressure, however, be direct, and the corpuscle be. immersed in a
thinnish fluid, it will resume the spherical form, the compressing
force being removed, owing to the elasticity with which it is endowed.
Size. — The size of the corpuscle is also liable to much variation,
this resulting mainly from the condition of the fluid, as to density, in
which it is immersed.
Thus, in water, or any other fluid, the density of which is less
considerable than that of its contents, the corpuscle imbibes by
endosmosis the liquid by which it is surrounded, to such an extent as
to cause it to exceed, by two or three times, its former dimensions.
(See Plate XI. Jig. 3.)
By reference, then, to the two particulars referred to, viz: the
density of the medium in which it dwells, and pressure, we are enabled
to explain all the varieties of form and size which the mucous cor-
puscle presents.
Properties. — From the preceding remarks on the structure, form,
and size of the mucous corpuscle, we perceive that in all these par-
ticulars, it accords closely with the white corpuscles of the blood;
we shall now proceed to show that there are other points of resem-
blance between the two organisms.
Thus reagents affect mucous corpuscles in a manner precisely similar
to that in which they act upon the white globules of the blood; water
causes them to increase in size, acetic acid contracts them somewhat,
and renders the nucleus and the molecules more distinct. Between
mucous corpuscles and the white globules of the blood there is, then,
a structural identity ; but let us see if there be not also a Junctional
correspondence.
NATURE OF MUCOUS CORPUSCLES.
Mr. Addison* conceives "that mucous and pus globules are altered
colourless blood-corpuscles," from which opinion it is evident that
gentleman believes that the white corpuscles of the blood pass normally
* Transactions of Prov. Med. and Surg. Association, vol. xii. p. 255.
mucus. 177
through the walls of the blood-vessels, although he does not appear
satisfactorily to have witnessed the exact manner of their escape.
The perfect identity of organization existing between the colourless
corpuscles of the blood and mucous and pus globules, would predis-
pose the mind to adopt that view as sufficient and correct, which
endeavoured to prove that they all had a common origin in the blood.
It must nevertheless be remembered that the notion of the identity
in origin of the mucous and pus globule with the colourless blood-
corpuscle, rests upon the single supposition that the latter does really
escape from the blood-vessels, in which originally it is formed.
It seems to me, however, that this statement, to which I was myself
at one time disposed to attach some importance, may be fairly chal-
lenged, seeing that the direct passage of the white corpuscles of the
blood appears never to have been clearly witnessed.
Moreover, the idea of any such escape of the white corpuscles is
opposed to that view which reasoning alone wTould lead one to enter-
tain; thus, if the colourless corpuscles of the blood possessed the
power of escape from their vessels, no good reason could be advanced
why the red globules should not also pass through them.
If the capillary vessels terminated by open mouths, which we know
that they do not in their normal state, then indeed it would be highly
probable that mucous and pus corpuscles were the white corpuscles
of the blood, escaped from the vessels.
I am disposed, then, to question the accuracy of the view enter-
tained by Mr. Addison, and to believe that the globules of mucus are
formed externally to the blood-vessels; the mucous glands or crypts
which are scattered so abundantly over the surface of all mucous
membranes, having a considerable share in their formation.
That the mucous-bearing glands are intimately connected with the
development of mucous corpuscles seems proved by the fact, that the
fluid expressed from them is filled with corpuscles of a smaller size
than ordinary mucous globules, and destitute of any admixture with
epithelial scales; these corpuscles certainly could not have found
entrance into the cavities of the glands from without. (See Plate
XL ^.6.)
The opinion that the mucous corpuscles are formed externally to
the blood-vessels, is also supported by the observations of M. Vogel,
who remarked that the plastic exudation which covers the surface of
a recent wound contains, at first, only minute granules : these after a
time become associated in two's and three's, and surrounded by a
12
178 ORGANISED FLUIDS.
delicate envelope; finally, fully-formed mucous or pus corpuscles
appear in the liquid.
Henle believes that the white corpuscles of the blood, of lymph
and of chyle, as well as those of mucus and pus, are elementary cells ;
and he says of the pus corpuscles that they are nothing else than
elementary cells in process of being transformed into those of
the tissue which the organism regenerates in the injured part; and of
the white globules of the blood he writes, they are, without the least
doubt, transformed into blood corpuscles.
This opinion of Henle accords closely with that of Addison, who
believes, as already stated, that out of the white globules of the blood,
all other corpuscles met with in the body are formed, the former
escaping from the blood-vessels.
I also regard the white corpuscles of the blood as elementary or
tissue cells, although at the same time the views entertained by myself
respecting them differ from those both of Henle and Addison. Thus,
I do not consider, with the former, that the colourless corpuscles are
transformed into red blood discs, nor with the latter, that every other
cell met with in the animal organism, proceeds from the white
corpuscles of the blood.
The white corpuscles of lymph, chyle, and blood, I conceive to be
transformed into the epithelial cells, which constitute the epithelium
with which the internal surface of the vessels of the entire vascular
system is provided.
The corpuscles of mucus I conceive to have an origin distinct
from the colourless globules of the blood ; but in like manner I regard
them as elementary or tissue cells, believing that they are finally
developed into the different forms of epithelium encountered upon the
surface of mucous membranes.
The corpuscles of pus are also elementary cells and mostly altered
mucous corpuscles.
The view just expressed as to the nature of the white corpuscles
of the blood, is one which has but recently impressed itself upon my
mind. It is not opposed, however, to the opinion previously put forth
of the connexion existing between these corpuscles and nutrition,
seeing that, whether in their early stage of development as colourless
blood globules, or in the more mature condition of their growth as
epithelial scales, they are doubtless to be regarded as secreting organs,
and as effecting some important change in the constitution of the
liquor sanguinis.
mucus. 179
The only respect in which the opinion that the colourless globules
of the blood are converted into the scales which "constitute the lining
epithelium of the vessels is at variance with a previously-expressed
view, is in relation to the escape of those globules as a usual occur-
rence; an opinion of Mr. Addison, in which I was formerly disposed
to concur, but which I am now inclined to reject.
A final reason which may be stated for disbelief in the identity as
regards the origin of the colourless corpuscles of the blood and
mucous globules, is the difficulty, not to say impossibility, of explaining
how these colourless corpuscles, having precisely the same form and
origin in the commencement, should, in one situation, be developed
into a shape and a structure so totally dissimilar to that which the
same corpuscles in another position exhibit, the varieties of form and
structure of epithelial scales into which the white corpuscles are
supposed to be developed being so considerable.
Mucous globules, then, are to be regarded as young epithelial scales,
as are also the colourless globules of the blood; they both have a like
structure and a corresponding function to perform, but they have a
different origin; thus, the mucous globules are developed externally to
the lymphatics and blood-vessels, while the colourless blood corpuscles
are formed within those vessels.
The further consideration of the ulterior development of mucous
corpuscles, or young epithelial cells, will come more appropriately
under the head of Epithelium.
Blood corpuscles not unfrequently occur mixed up with mucous
globules, as in the mucus thrown off during parturition (see Plate
XII. jig. 1), and as in the rust-coloured expectoration of Pneumonia.
THE MUCUS OF DIFFERENT ORGANS.
After the threefold division of mucus which we have given, founded
upon the structure of the membranes by which it is secreted, and
after the description which has been entered upon of the peculiarities
appertaining to the mucus of each of those divisions, it will be
unnecessary to enlarge at any length upon the characters presented
by the mucus secreted by the membrane which belongs to each
particular organ or part; it will be sufficient just to enumerate the
names of the membranes by which each description of mucus is fur-
nished, and to point out any peculiarities which the mucous secretion
of any particular organ may present: this having been done, and the
distinctive characters of the three forms of mucus having been
180 ORGANIZED FLUIDS.
recalled to mind, we shall then be in a position to assign to the mucus
of each locality its principal characteristics.
Thus, the mucus furnished by the nasal and bronchitic mucous
membranes, and which may be called nasal and bronchitic mucus, as
also that of the digestive tube, from the pyloric orifice of the stomach
unto near the termination of the rectum (the caecum alone excepted),
of the urethra, prostatic gland, vesiculae seminales and the uterus,
belongs to the first division of mucus, viz : that which is secreted by
the true mucous membranes. (See Plate XII. fig. 3.)
The mucus of the vagina presents the best example of the mucus
of the second class, which is secreted by the false mucous membranes.
(See Plate XII. fig. 1.)
Lastly. The mucus of the mouth, rectum and bladder, appertains
to the third description of mucus, and which is supplied by the mixed
mucous membranes. (See Plate XII. fig. 2.)
Vaginal and Uterine Leucorrhea.
One practical result arising from the discrimination of mucus into
different kinds may here be alluded to ; thus, by means of the differ-
ence in the microscopic characters of the mucus secreted by the
uterus and that furnished by the vagina, it is in our power to decide,
in cases of leucorrheal discharge, whether the affection has its seat
in the mucous membrane of the uterus or in that of the vagina. The
mucous membrane of the uterus, as we have seen, belongs to the
class of true mucous membranes ; that of the vagina, on the contrary,
to the false mucous membranes. Now, if the leucorrhea be uterine,
the discharge will present the globules characteristic of the secretion
produced by the class of true mucous membranes ; if, on the other
hand, it be vaginal, the mucus will contain the epithelial scales which
belong to the mucus of false mucous membranes; moreover, the
former mucus will be alkaline, and the latter acid.
Effect of Acid Mucus on the Teeth.
The degree of acidity presented by the mucus of the mouth varies
considerably, according to the relative proportions of mucus and
saliva which exist in the mouth at the time at which the reaction of
its secretions is tested, and which proportion differs both at differen'
times of the day and in different states of the system, and especiallj
of the stomach. The mucus of the mouth we know to exhibit ir
states of health an acid reaction, while the saliva, on the contrary,
MUCUS. 181
manifests an alkaline constitution ; the tendency of these two fluids
is therefore to produce a neutral secretion, and this explanation will
account for the opposite results which have been obtained by different
observers. The best time to ascertain the chemical reaction of the
buccal mucus is in the morning, when there is an accumulation of it
on the tongue and around the gums; and the best method of deter-
mining the acid or alkaline qualities of the saliva, is first to scrape
the tongue well, and as far as possible free the mouth of mucus, and
then proceed to test the saliva as it issues from the orifices of its ducts.
A highly acid condition of the mucus of the mouth is assuredly
productive of injurious effects upon the teeth. Although this state
of the buccal mucus cannot be regarded as giving rise to the peculiar
caries to which the teeth are so remarkably liable; nevertheless, it
cannot be doubted that it predisposes the teeth to this affection, and
that it hastens greatly the progress of the decay when once this has
commenced. To correct the condition of the stomach, if it be faulty,
the internal administration of alkalies should be had recourse to; and
to remedy the local acidity, tooth powders, composed principally of
of some alkaline carbonate, should be employed.
The Vaginal Tricho-Monas.
M. Donne has discovered in the vaginal mucus of women labouring
under discharges, either specific or otherwise, a new species of human
parasite belonging to the order of Infusoriae. This animalcule,
owing to its resemblance to the spherical mucous globules with which
it is constantly associated, is with difficulty discoverable by those
who are not practically familiar with its appearance, and the mode of
detecting it. Thus, it presents nearly the same size, form, granular
structure, and colour as the mucous corpuscles alluded to; it is to be
distinguished from these, however, by the independent locomotive
power which it possesses, the movements which it performs being
produced principally by means of a long lash or cilium with which
its anterior extremity is furnished, and the presence of which causes
the animal to lose somewhat its circular contour, and assume a form
approaching the oval ; in addition to this long cilium, three or four
other shorter cilia exist, which surround the mouth, and which can
only be satisfactorily detected when the motions of the animalcule
become somewhat retarded. (See Plate XII. fig. 6.) In order that
it may be seen alive and in active movement, it is necessary that the
mucus containing it should be submitted to examination as soon as
182 ORGANIZED FLUIDS.
possible after its removal from the vagina; the animal once dead, it
is then almost impossible to distinguish it from a mucous corpuscle.
M. Donne, on first discovering this parasite, was for some time in
doubt as to whether its occurrence was to be regarded as having any
connexion with the specific disorders of which the vagina is sometimes
the seat, and he has at length arrived at the conclusion that no such
relation as that suspected exists, and that any inflammation, specific
or otherwise, sufficiently active to give rise to the secretion of
puriform matter, may be accompanied by the tricho-monas which has
been described.
In addition to the positive characters which have been indicated,
denoting the presence of this animalcule, there is another altogether
indirect which serves to signalize its existence in the vaginal mucus,
and this is the presence in it of air-bubbles, which are not encountered
in healthy mucus.
Vaginal Vibrios.
The tricho-monas is not the only animalcule which lives in the
mucus of the vagina; there are frequently met with in it minute
vibrios, which, to be satisfactorily seen, require to be viewed with a
magnifying power of not less than the ji? of an inch.
In the same manner as the tricho-monas, they always occur in
connexion with pus globules ; they are not, however, any more than
the tricho-monas, to be regarded as indicating the existence of specific
or venereal affections, although they are not unfrequently met with
in the secretion of chancres of an undoubtedly specific character.
pus. 183
ART. IV. PUS.
GENERAL CHARACTERS.
Healthy, phlegmonous, or laudable pus, is a fluid of the colour
and consistence of cream, readily miscible with water, in which after
a time it sinks; it does not admit of being drawn out into threads,
and exhibits usually an alkaline, though sometimes an acid, reaction.
Like mucus, which it resembles so closely, pus is made up of two
constituents, the one fluid, the other solid; these, if allowed to stand
at rest for a time, will undergo a spontaneous separation from each
other, the corpuscles subsiding to the bottom, and the fluid or serum
floating upon the top; this also will be frequently observed to be
covered with a delicate film composed of oil globules. The fluid
portion of pus, as of mucus, is probably the only essential, as it
certainly is its only distinctive constituent; but while the latter is
sometimes free from globules, the former is never without a greater
or less amount of corpuscles, on the presence and numbers of which
its opacity, its colour, and its consistence mainly depend.
The general characters of pus, however, undergo many changes in
disease; thus its consistence, colour, smell, and all other sensible
qualities, vary greatly in pathological conditions.
IDENTITY OF THE PUS AND MUCOUS CORPUSCLE.
The globules of pus resemble in all essential particulars those of
true mucus, the characters of which have been already described;
thus, they present the same form, the same constitution, and they
comport themselves in a manner almost identical with chemical
reagents. (See Plate XI. fig. 1, and Plate XIII. fig. 1.)
In one respect only can a difference in the effect of reagents on the
pus and mucous corpuscles be detected; this difference is, however,
one of degree, and not of kind; thus, the mucous corpuscle is less
readily acted upon by the acids than the pus globule; in the former,
a solution of acetic acid, not too concentrated, will often disclose but
a single, although large, nucleus ; while the same solution applied to the
latter, will render apparent seldom less than three or four nucleoli.
(See Plate XIII. fig. 2.) This is, however, by no means a constant
result, and the effect of the application of strong acetic acid to the
mucous globule is almost invariably to render apparent three or four
184 ORGANIZED FLUIDS.
nucleoli; so that, from the circumstance of the number ot nuclei
disclosed by acetic acid, no opinion can be formed as to the nature
of the corpuscle, whether it be a mucous or a pus corpuscle. Of the
accuracy of this view, notwithstanding that a contrary opinion is
held by many observers, not a doubt can be entertained.
It is not in every example of pus that we find the well-formed and
spherical corpuscles, which characterize healthy and normal pus. In
the pus which has been long secreted, as in that of old abscesses, we
find but few corpuscles, the majority being broken up and reduced to
their elementary particles. (See Plate XIII. fig. 5.)
The best examples of pus corpuscles are seen in pus which has
been recently secreted, as in that just formed on some healthy
granulating surface. (See Plate XIII. fig. 1.)
When, therefore, pus and mucous globules are spoken of, it is not
to be understood that these terms indicate two distinct structures,
but merely the occurrence of the same solid element in two fluids,
which, although usually presenting some points of difference, are in
all probability not essentially distinct.
THE NATURE, ORIGIN, AND FORMATION OF PUS CORPUSCLES.
In having indicated the nature of mucous globules, we have also,
to a very great extent, pointed out that of pus corpuscles, seeing that
the corpuscles of both have an organization precisely similar.
One of the earliest opinions formed in reference to the nature of
pus was, that it was constituted of blood deprived of its colouring
matter, a view which was entertained even before the discovery of
the blood corpuscles themselves.
Subsequently to the period of the detection of the red corpuscles
in the blood, many observers have conceived that pus consists of
these corpuscles altered merely in colour.
A third opinion in reference to the formation of pus and mucous
globules is that of Vogel, who maintained that they arose out of a
transformation of the epithelium, the nuclei of which constituted the
corpuscles. This view, although not without ingenuity, has but little
even of probability to recommend it, and it will be perceived that it
is the very reverse opinion to that which is maintained in these pages,
and which is, that the epithelium is itself derived from mucous and
pus globules.
We have already, under the head of Mucus, adverted to the
opinion of Addison, that mucous and pus globules are altered colour-
pus. 185
less blood corpuscles, an opinion which we have also endeavoured to
refute, principally by reference to the impossibility, save from lesion,
of the escape of the white corpuscles from their containing vessels.
Reference has also been made to the view entertained by Henle
respecting the nature of pus corpuscles, who says of them that they
are nothing else than elementary cells in process of being trans-
formed into those of the tissue, which the organism regenerates in
the injured part.
I also agree with Henle in considering pus corpuscles to be
elementary cells, but I differ from him in not regarding them as
representing the cells of the tissue in which the pus is formed.
Pus corpuscles I conceive to be identical with mucous corpuscles,
and these again are to be regarded as repi'esenting an early stage in
the development of epithelial scales.
Further, it is here supposed that the formation of pus is to be
viewed in the light of a salutary process, and as indicating the effort
on the part of the organism, where suppuration occurs as the result of
lesion of any kind, to repair the mischief sustained, and which it
does by the elaboration of pus corpuscles capable of being transformed
into a protecting epithelium.
In support of this view, reference may be made to the fact that it is
by no means uncommon to encounter epithelial scales mixed up with
the ordinary pus corpuscles contained within the cavity of an
abscess, or covering the surface of an old ulcer.
But, it may be asked, how happens it then that all pus corpuscles
do not become converted into epithelial scales, and that so many of
them are discharged or thrown off from the system without attaining
to the higher degree of development of which they are stated to be
susceptible ?
This arrest of development doubtless arises from the rapidity with
which the pus corpuscles are formed, and which is indicative of the
strength of the Vis medicatrix naturce, the result of which is that the
earlier formed corpuscles become displaced by the more recently
developed ones, and are thus removed without the sphere of growth,
in consequence of which they perish.
Having thus considered the nature of pus corpuscles, we will next
endeavour to form some opinion in reference to their origin and mode
of formation; in these respects also an essential correspondence
doubtless exists between pus and mucous globules.
Mandl attributes to the pus globule the same mode of formation
1S6 ORGANIZED FLUIDS.
which he has described as belonging to the white corpuscles of the
blood, that is, that they are formed external to the vessels by the
aggregation of molecules precipitated from the fibrin, and hence
Mandl terms both the white and pus corpuscles "fibrinous globules."
This view of the formation of pus corpuscles is supported also by
the observations of Vogel (already cited) made upon abraded surfaces.
Mandl, therefore, is most probably correct in his opinion as to the
mode of formation of pus corpuscles, viz: by precipitation; but it is
at the same time almost certain that they are not constituted of fibrin,
as supposed by that micrographer : this may be inferred from the
different manner in which acetic acid acts upon fibrin and pus
corpuscles; thus, the former swells up, and is rendered soft and friable
by its application, while the latter under its influence become smaller,
and their contained molecules more distinct.
Donne dissents from Mandl's view altogether. At page 191 of the
Cours de Microscopie, M. Donne expresses himself as follows: —
"Thus I do not admit that the globules of pus are formed at the
expense of the fibrin of the blood ; that they ought to be considered
as a sort of precipitate of the fibrinous part of the fluid blood; and in
spite of their analogy of structure and composition with the white
globules of the blood, I nevertheless do not admit that they have any
thing in common in their origin and in their intimate nature .with
these last. I regard the globules of pus as a product of special
secretion direct from the pus forming membrane."
There appears to me to be much of error in the preceding observa-
tions: there is doubtless very much in common between the white
corpuscles of the blood and pus globules, viz: a common mode of
formation and a common function to perform.
At the same time it must be admitted, with Donne, that the surface
or membrane, from which the pus proceeds, is also intimately associated
with the development of the pus corpuscles.
DISTINCTIVE CHARACTERS OF MUCUS AND PUS.
We have now to ask ourselves the question, which doubtless many
have applied to themselves before, viz: what are the distinctive
characters between mucus and pus revealed to us by the microscope,
and the satisfactory recognition of which has been deemed to be of so
much importance?
To this inquiry no sufficient answer has as yet been returned: this
difficulty the microscope has failed to solve; and this, in all probability,
pus. 1S7
for the very adequate reason, that between the fluids in which a
distinction has been sought, no microscopic difference exists. The
inquiry has been made on the false assumption that mucus and pus
are really essentially distinct ; and its importance has been magnified
by the idea that it would impart, as indeed it undoubtedly would do,
if real, increased assistance in the diagnosis of disease.
Since, however, the establishment of the fact that pus may be
formed independently of any appreciable structural lesion, much of
the interest which was supposed to attach to this inquiry has been
lost, and that which still appertains to it has been further lessened by
the demonstration at which we have arrived by means of the micro-
scope, of the perfect identity of pus and mucous corpuscles.
Now, the manifestation of this identity by the microscope is not
less a triumph of that instrument than if it had really proved that the
notion of physiologists was actually founded on fact, and that there
does really exist a tangible difference in the microscopic characters
of the two fluids.
Notwithstanding the absence of any positive known microscopic
character, whereby at all times, and in all conditions, pus may be
discriminated from mucus, this want of knowledge, arising from the
very sufficient fact to which allusion has already been made, viz:
that no such character really exists, the two fluids under discussion
may frequently be distinguished, at a glance, by certain outward and
physical properties and appearances, and this is especially the case
when they occur without admixture with each other.
These differences in the outward character of the two fluids are
not always, however, equal to their discrimination, and which arises
from the fact, that they are all of them subject to the greatest possible
variation, so that there is not one which can be regarded as truly
distinctive. Thus, in morbid conditions, the one fluid will pass by
insensible degrees into the other, or they will both be mingled together
in such proportions as to set at defiance all physical means employed
to distinguish them.
But it may be said that the chemist can at all times distinguish pus
from mucus: there can be no doubt but that, when all other means
have failed, he can occasionally arrive at a tolerably accurate con-
clusion, but it is conceived that his powers in this respect are also
limited.
Now, the physical and chemical difficulties encountered in the
endeavour to discriminate pus from mucus arise in all probability,
188 ORGANIZED FLUIDS.
from the same cause which rendered it microscopically impossible so
to do, viz : that no constant or essential difference does really belong
to these fluids, whereby at all times they may be characterized.
Normal mucus and pus may be contrasted as follows : Mucus is
a thick, tenacious, and transparent substance, easily admitting of
being drawn out into threads, not readily miscible with water, in
which it floats, not so much from its less specific gravity as from the
circumstance of its great tenacity, allowing it to retain in its substance
numerous air globules, which thus render it specifically lighter than the
water: it exhibits sometimes an acid, and sometimes an alkaline reac-
tion, according to the nature of the surface from which it proceeds ;
and it contains imbedded in its substance solid particles of two forms,
globules and scales: the former are present in alkaline mucus, the
latter in that which manifests an acid reaction.
Pus, on the contrary, is a thick, opaque, somewhat oily substance,
which does not admit of being drawn out into threads, is readily
miscible with water, in which it sinks ; its chemical reaction varies,
being sometimes alkaline, at others acid : the solid particles which it
contains are mostly of one kind, globules : these are always very
abundant, and float freely in the fluid portion of the pus, while in that
of mucus they are unable to do so on account of its tenacity.
Healthy mucus and pus, when thus contrasted, may frequently be
distinguished from each other, but it is in unhealthy conditions of
these two fluids, and especially when they occur mixed together in
variable proportions, that the difficulty of discrimination is felt, and
that the want of a certain and positive character, whereby the
diagnosis may be always established, is experienced.
This mixture of mucus and pus may actually exist, or it may not,
in cases of suspected phthisis, in which sputa are present. Now, it is
in cases of this description that we recognise the importance of the
discrimination of these substances, and it is precisely in these and
similar instances that the microscope utterly fails us, for the want of
an ascertained and tangible difference in the two fluids submitted to
the test of its powers.
Even the most marked physical qualities of pus, such as its opacity
and tenuity, may all be effaced by the employment of certain reagents,
and converted into those which are characteristic of mucus; thus,
pus, by the addition to it of liquor potasses or of ammonia, is rendered
transparent, and is transformed into a thick and tenacious substance,
resembling mucus closely. This singular fact has been noticed by
pus. 189
both Addison and Donne, and on it the former clever observer has
built a theory remarkable for its ingenuity, but which is here, never-
theless, deemed to be incorrect.
The change of pus, from an opaque substance to a transparent one,
doubtless results from the solution of the pus corpuscles, and to the
presence of which the colour and opacity of pus is due ; of the
increased density and tenacity of the pus thus treated, it is less easy
to afford a satisfactory explanation.
Addison thus accounts for it: The mucus and pus globules, he says,
contain filaments imbedded in a fluid; these. the liquor potasses sets
free by dissolving the envelopes of the corpuscles, and it is upon these
filaments that the tenacity of mucus, and of pus so acted upon,
depends. Mr. Addison, however, carries his reasoning upon the fact
of the conversion of pus into a fibrillating substance similar to mucus
still further. The white corpuscles of the blood, he states, also
contain fibres, and that these corpuscles, immediately on their abstrac-
tion from the system, burst, giving issue to the contained filaments.
These filaments he conceives to constitute the fibrin of the blood,
which he declares does not exist in that fluid as fibrin, but is only
liberated from the corpuscles after the abstraction of the blood from
the system.
The entire of this theory is here conceived to be erroneous, and
this for the following reasons :
1. The existence of such filaments in the white corpuscles has not
been proved.
2. The bursting of these corpuscles, referred to by Mr. Addison,
is an occurrence which is rarely, if ever, seen to take place while
they remain imbedded in the liquor sanguinis.
3. The actual consolidation of the fluid fibrin may be witnessed to
occur on the field by the microscope in a drop of blood, and wholly
independent of any rupture of the white corpuscles, which remain
without appreciable alteration.
There is some consolation, however, in knowing that this inquiry
is not of so much importance as it would appear; for even were we
able to make the distinction which has been the subject of so many
anxious thoughts, and decide that pus did exist in the sputa, yet this
fact, viewed separately, would not prove that disease of the lungs did
really exist, since it is ascertained that pus may be formed without
any structural lesion; and, further, if lesion were really present, it
would not necessarily follow that this had its seat in the cells of the
190 ORGANIZED FLUIDS.
lungs, for it might be situated either in the bronchi or larynx. Thus,
even in this supposed case, the diagnosis would be subject to consider-
able uncertainty.
Various opinions have been expressed by different observers in
favour of the possibility of distinguishing pus from mucus. To some
of these we will now refer.
There is always met with in pus, in greater or less quantity, globules
of oil; the presence of these was conceived by Gueterboch to afford
a sign, absolutely distinctive, between pus and mucus ; that they are
not so, however, is proved by the fact that similar globules are
occasionally encountered in normal mucus.
Weber conceived the idea that the fluids might be distinguished by
the size of the globules contained in them, the pus globule being twice
as large as that of mucus : this character is likewise too uncertain,
and too variable for the purposes of discrimination.
Lastly, Gruithuisen indicated, in solutions of pus and mucus in
water, certain animalculae; those generated in the former being
different from those formed in the latter solution. By means of these
he asserted that pus might always be known from mucus; but the
infusoria described by him are not confined to the fluids in question,
but are such as are formed almost indifferently in any solution of
animal matter. It would appear, then, that up to the present time no
satisfactory and direct means of distinguishing pus from mucus have
been detected, and this for the reason assigned, that the two fluids are
essentially identical.
DISTINCTIONS BETWEEN CERTAIN FORMS OF MUCUS AND PUS.
Although it is impossible to discriminate between true mucus and
pus by means of the microscope in a positive manner, we are yet
enabled to distinguish with that instrument false mucus from pus,
because in this mucus the corpuscles exist in their fully developed
form of tesselate epithelium. Now, this power of discrimination is
not without importance, as will be perceived immediately.
Many persons on arising in the morning are in the habit of expec-
torating more or less of a substance bearing much resemblance to
pus. This habitual occurrence is not unfrequently a source of much
uneasiness, not merely to the person the subject of it, but also to his
medical adviser whom he is led to consult upon it.
Now, in such cases as these, it is often in our power to dispel the
anxiety of our patient and our own at the same time ; for the solid
pus. 191
constituents of such sputa are frequently found to consist almost
entirely of epithelial cells, in which case we may safely pronounce
that they are not purulent; if, on the contrary, the sputa contain only
globules, the evidence which this fact would furnish, although appar-
ently, and indeed most probably, unfavourable, would still be but of a
doubtful nature.
Again, the microscope will frequently determine the nature of a
suspected fluid, by indicating in it the existence of shreds of cellular
tissue, muscular fibrillae, and a variety of other organisms which enter
into the formation of the human body; and by the presence of one
or more of which, not merely the nature of the puriform matter may
be ascertained, but also the locality from which the pus had itself
proceeded.
DETECTION OF PUS IN THE BLOOD.
From what has been said in reference to the structural identity ot
the white corpuscle of the blood with that of mucus and pus, we are
prepared for the announcement that no known characters exist
whereby the presence of pus in the blood may be established by the
microscopic examination of that fluid.
That the elements of pus in some cases are really present in the
blood, circulating with it, scarcely admits of a single doubt, since it
is not unfrequently met with in situations, such as on the lining
membranes of the vessels, where it is utterly impossible for it to
remain without some portion of it becoming commingled with the blood.
The same fact is also proved by the spontaneous absorption ot
large collections of matter, an occurrence which is not unfrequently
witnessed, and which is only to be accounted for on the assumption
that the elements of pus are again absorbed into the blood from
which originally they were derived.
There can scarcely be a question, then, that pus is occasionally
contained in the living blood, although we possess only indirect
means of establishing this fact ; and according to the views here
entertained, it may be present in the blood in two ways: thus, as we
have seen, it may be formed in the blood-vessels themselves, or it
may be formed without those vessels, and again reabsorbed into the
blood from which in every case it almost immediately proceeds.
But pus, as we know, is composed of two elements, the one fluid,
the other solid, the globules. Now, we must not expect to see pus
circulating in the blood as pus, although that liquid may contain all
192 ORGANIZED FLUIDS.
the elements of pus: the fluid portion of course, as soon as it enters
the circulation, is dissipated, the solid alone remaining, and this does
not constitute pus, but is only one element in the constitution of
that fluid.
In certain states of disease, the presence in the vessels of an
unusual number of white corpuscles has been observed; now it is
but little probable, that these are derived from the reabsorption of
pus, which had been previously formed without those vessels ; it is
more natural, and more consonant with known facts, to suppose, that
this accumulation is to be regarded as an indication that the disposi-
tion to the formation of pus, on the part of the blood and of the
system, exists to an unusual extent, and that such a condition of the
vital fluid always precedes sudden and extensive purulent collections.
Except in the case of the formation of pus in the blood-vessels
themselves, it is scarcely possible to suppose that the pus corpuscles
are taken bodily into the circulation again; but it would rather
appear, from the condition of pus in most abscesses, that the corpuscles
become disintegrated and reduced to their elementary particles, and
that thus they enter the circulation again in a fluid state.
The artificial admixture of pus with the blood immediately after
its escape from a vein, and before its coagulation has commenced, is
productive of somewhat singular results. The clot formed in blood,
which has been mixed with one quarter part of its own quantity of
pus, is soft, diffluent, and dark coloured, sometimes almost livid, and
the red corpuscles are found to be wrinkled and deformed, part of
their colouring matter having escaped from them and passed
into the serum.
These changes ensue in from twenty-four to forty-eight hours, and
possibly result from the state of decomposition in which the pus itself
might have been when introduced into the blood, and which condition
it communicated to the mass of the blood itself.
There are many substances and fluids having resemblance to pus
which are not really purulent; thus, softened clots of fibrin, which
are so frequently encountered, especially in phlebitis, bear the closest
possible similitude to true pus in general appearance, and yet in their
intimate structure they are totally dissimilar, as may be clearly
determined by means of the microscope.
If a portion of softened fibrin be examined microscopically, it will
pus. 193
be found to be made up of a granular material, from which pus
corpuscles, or corpuscles similar to them, are either entirely absent,
or in which they occur but in very small numbers. Now, with true
pus, the reverse is the case; the corpuscles are its chief and most
conspicuous element.
It is only by means of the microscope that the nature of softened
fibrin can be ascertained; until within the last few years it has always
been mistaken for true pus, and the occurrence of masses of fibrin
thus altered in the blood-vessels has led to the opinion that the
formation of pus in them is not an unfrequent event.
On the other hand, fluids are sometimes met with which look very
unlike proper pus, and which are yet found on examination to be
veritable pus. These facts show the necessity of a careful microscopic
examination in all important and doubtful cases.
METASTATIC ABSCESSES.
Another notion, the erroneousness of which has been rendered
manifest by means of the microscope, is that which has been enter-
tained in reference to the removal of an abscess seated in one part of
the body, and its subsequent deposition in another situation.
The knowledge of the existence of pus corpuscles in the fluid of
abscesses, and the fact that no channels exist by which they can be
conveyed bodily from one part of the system to another, clearly show
that any such translation of the matter of an abscess as that
presumed is an occurrence beyond the range of possibility.
Abscesses may indeed be reabsorbed into the system, as daily
observation teaches us to be the case, and other purulent depositions
take place subsequently to the resorption of the matter of the first
abscess ; but the elements of pus, and assuredly its solid constituents,
are not carried into the constitution bodily and without alteration;
the corpuscles doubtless become disaggregated, and in all probability
reduced to a fluid state previous to absorption, so that it cannot be
the same purulent matter which constitutes the pus of supposed
metastatic abscess.
The simultaneous or consecutive occurrence of abscesses in
different parts of the body, may be satisfactorily explained by reference
to the condition of the system, or perhaps more immediately of the
blood itself, which is evidently charged with purulent matter, and of
which it. relieves itself by the formation of abscesses.
13
194 ORGANIZED FLUIDS.
VENEREAL VIBRIOS.
M. Donne has discovered in- the pus of syphilitic primitive
ulcerations, and of chancres which have not been treated with topical
applications, numerous vibrios of excessive tenuity. (See Plate
XIII. fig. 6.)
These vibrios are not encountered in the pus of secondary
chancres, nor even in that of buboes, which, according to the
experiments of M. Ricord, is capable of giving origin to a chancre
by inoculation.
Neither are they to be met with in the pus proceeding from
wounds, nor in fetid pus altered by the contact of the air.
Again, in the instances in which suppuration has been artificially
excited around the edge of the glans penis, the ordinary situation of
primary syphilitic ulcerations, the vibrios are invariably found to be
wanting in the discharge thus created. This experiment proves that
locality has nothing to do with the development of the vibrios.
Finally, if inoculation be practised with the pus of a chancre
containing the vibrios, the matter of the pustule resulting from the
inoculation will also be found to contain the animalcules.
Now, the inference to be deduced from these several facts and
experiments is, that if the vibrios in question be not intimately
connected with the propagation of the syphilitic virus, that the matter
of syphilis is at least peculiarly fitted for their development.
It is probable that the presence of these vibrios accounts, in a
great measure, for the beneficial effects of topical applications,
which act by killing the animalcules.
MILK. 195
ART. V.— MILK.
The general aspect and qualities of milk are known to all; they
need not therefore be here detailed.
Healthy and fresh milk, when submitted to the action of test paper,
exhibits an alkaline reaction: in states of disease, however, and some
time after its removal from the mammary gland, it frequently
manifests more or less of an acid reaction.
Like the other fluids which have as yet been described in this
work, milk is made up of two distinct elements, the one fluid, the
serum — the other solid, the globules; these, a few hours after its
abstraction from the system, and when left at rest, undergo to a
certain extent a spontaneous separation from each other, the larger
globules, ascending to the surface, forming a scum or cream, while
the smaller remain diffused through the subjacent serum.
The following analyses will serve to give an idea of the
composition of milk.
The relative proportions of the organic constituents of human
milk are thus estimated by Simon :
88 • 06 water.
3 ' 70 caseine.
4 "54 sugar.
3 • 40 butter.
0*30 salts, extractives, &c.
The inorganic components of the milk of the cow are computed
as follows by Haidlen :
Chloride of sodium - - 0 ■ 024.
Chloride of potassium - -0144.
Soda - - - -0-042.
Phosphate of lime - - 0'231.
Phosphate of magnesia - - 0 ■ 042.
Phosphate of the peroxide of iron - 0*007.
From the above brief sketch of the constitution of the milk, it will
be seen that a very close analogy exists between that fluid and the
blood : like it, the milk is made up of two parts — the one solid, the
other liquid ; like it, too, it contains all the elements requisite for
nourishment and development, it serving for both during a very long
period of the life of the human species.
196 ORGANIZED FLUIDS.
THE SERUM OF THE MILK.
The separation of the serum and the globules, accomplished in an
imperfect manner naturally, is more completely effected artificially
by filtration; the serum, by means of the ordinary filtering paper,
may be obtained transparent and colourless, almost free from globules,
these being for the most part retained upon the filter.
It may, however, be observed, that the first portions of serum
which pass through the paper will be more or less coloured in conse-
quence of their containing a certain number of the smaller globules,
which had escaped through the interstices of the paper; these
coloured and semi-opaque portions of serum should be rejected.
The serum contains dissolved in it the sugar, and the principal
portion of the cheese of milk, as well as certain salts, the principal
of which are pointed out in the analysis of Haidlen.
The cheese or caseine is an animal principle, which in its proper-
ties approaches closely fibrin: it is precipitated by the mineral, the
acetic, and the lactic acids.
Although the greater portion of the caseine exists in the milk in a
fluid condition, M. Quevenne appears to have established the fact,
that it is also present in a solid state in the form of globules, these
being exceedingly small, and refracting but slightly the light; the
same globules may also be detected in recently precipitated cheese.
(See Plate XV. fig. 5.)
M. Donne has shown that these cheese globules may be demon-
strated by the process of filtration; thus, the first few drops of the
milk of the cow, the ass, or the goat, which pass through the filter,
and which are generally white and opaque, being rejected, and the
second portion of filtered milk being preserved, and allowed to remain
undisturbed for a few minutes, it will be seen to separate into two
parts, the inferior of which is clear and transparent, while the
superior is somewhat opaque. Now, if a drop of the fluid of this
inferior layer be examined with the microscope, it will be found to
contain an innumerable quantity of globules of exceeding minuteness,
and refracting the light but feebly, as well as occasionally other
globules more rare, larger, and refracting the light very strongly; the
former are the cheese globules, and the latter the proper milk globules.
MILK. 197
THE GLOBULES.
It is to the presence of the globles which occur in such vast quan-
tities in each drop of healthy milk that the colour and opacity of that
fluid is due.*'
These globules are of perfect rotundity, their surface being smooth,
presenting a pearly aspect, and refracting the light strongly; the cir-
cumference of each globule is dark and the centre light : the globules
vary greatly in size; the smallest, which are in active molecular
movement, being reduced to mere points, and not exceeding the
t 8-7oo of an inch, the largest frequently attaining the 20V0 of an inch,
and the medium size ranging between the 4 oV 0 of an inch in diameter
and the 45V o- (See Plate XIV. fig. 1.) In milk which is healthy,
the globules float freely in the serum, and do not adhere to each other.
Such is the form, appearance, and variety of size exhibited by the
milk globule; much difference of opinion has existed in reference
to its organization, some observers conceding to it a very complex
structure, others denying it even the most simple organization.
Some of the more remarkable of the opinions entertained by the
more noted investigators may here be referred to.
According to Turpin, "the structure of the milk globule consists
of two spherical vesicles, fitting the one into the other, and enclosing
in their interior very fine globules and buttery oil."f
Mandl says, " the globules of milk ought then to be considered as
organized corpuscles, composed of a membrane probably formed of
cheese, and of contents which constitute the butter." J
Henle writes, the globules of milk "are not simple molecules of
grease, and have an independent membrane surrounding them ;"§
this he elsewhere states to be probably composed of caseine, in which
respect there is an agreement of opinion between Henle and Mandl.
The complex structure ascribed to the milk globule by Turpin it is
altogether impossible to demonstrate ; and the experiments and obser-
vations which have hitherto been made in reference to its constitution
* Leeuwenhoek first clearly indicated the existence of these globules in the milk
in the following terms: " Vidi multos globulos, similes sextas parti globuli sanguinei;
et etiam alios, quorum bini terni aut quaterni se invicem modo attingebant, fundum
versus descendere; et multos varies magnitudinis globulos in superficie fluitantes,
inter quos posteriores adipem sive butyrum esse judicabam."
f Annates des Sciences Naturelles. j Anat. Micros, p. 53.
§ Anat. Gen. t. vii. p. 522.
198 ORGANIZED FLUIDS.
are entirely opposed to his view, which may safely, therefore, be con-
sidered to be incorrect.
Mandl founded his belief of the existence of a distinct membrane
enveloping the globules mainly on the following observation: He
remarked that if a little drop of milk be compressed strongly between
two plates of glass, the upper plate at the same time being drawn
over the surface of the other in a straight line, the milk globules will
be broken up by the compression, and drawn out into a certain form :
if a magnifying-glass be applied to the globules thus compressed, they
will be seen to present the appearance of long pale and straight lines,
with smaller straight lines placed usually at right angles to the larger
ones. "These little lines," he says, "are nothing else than the curled
membranes of the globules, the contents of which, the butter, consti-
tuting the long streaks : we may easily convince ourselves of this by
adding a little water. The streaks disappear, and we see in their
place oleaginous drops of different forms, while the little membranes
remain either attached to the glass or indifferently curved, swimming
in the serum. These membranes are insoluble in ether, which dis-
solves the drops."
These observations of Mandl, presuming for a moment that they
are accurate in every particular, are yet insufficient to prove the
existence of a distinct membrane surrounding the globules, although
they certainly would be so, if correct, to establish the fact that they
are constituted of two different substances, the one of which is soluble
in ether and the other insoluble. Had iodine been employed, and
had it been imbibed by the supposed membrane, and turned of a deep
brown, the reality of the existence of the membrane in question might
have been considered as demonstrated : but we know that iodine does
not affect the colour of the milk globule in the least.
I am far, however, from attaching the smallest importance to the
experiment of Mandl, because I conceive that he has misinterpreted
the appearances which he noticed. The larger streaks are not con-
stituted of a single elongated globule, but are made up by the union
of several milk globules, as is evident — first, from the size of the
streaks, and, second, from the traces which they bear of such a com-
position in themselves; as, for example, the occurrence of contractions
at certain intervals, while the smaller lines, and which are most
generally absent, are formed usually by other globules of less size
joining at an angle the larger streaks. The solubility of the one in
ether and the insolubility of the other in that reagent, I have not been
able to observe.
MILK. 199
The opinion of Henle, that the milk globule is furnished with an
envelope, rests chiefly upon the manner in which acetic acid acts
upon it.
Henle thus describes the effects of the application of acetic acid:
" Treated by dilute acetic acid, the globules of milk undergo, little
by little, a remarkable change; some of them become oval or take the
the form of a biscuit; upon others, appear gradually on one or many
points a smaller globule, which rests upon the margin, and increases
in an insensible manner." *•■*.*« If more acetic acid be added,
the milk globules appear, as it were, melted down with smooth but
irregular borders : they approach the one to the other, and unite into
large masses, which resemble perfectly melted fat which has run
along in an irregular manner. When to a drop of milk are added
two drops of concentrated acetic acid, and the mixture then placed
under the microscope, we no longer perceive any regular globule of
milk, or, at least, we discover but very few: the most are reduced
into one or several irregular particles, which, with the naked eye,
may be distinguished upon the surface of the drop, which otherwise
has become clear. The same changes are produced in the space of
a few days, when the milk, abandoned to itself, becomes acid by the
metamorphosis of its sugar."*
These ingenious observations of Henle, like those of Mandl, are
yet insufficient to demonstrate the existence of a distinct and organ-
ized membrane surrounding the milk globule, although they would be
assuredly so, if correct, to render it quite certain that it is enveloped
with a coating of a material very distinct from fat, and probably of
the nature suggested by Mandl and Henle
Here, again, however, it becomes a question whether the appear-
ances noticed by Henle have not been misinterpreted, and whether
the internal buttery substance does really protrude through apertures
in the envelope of the globule occasioned by the action of acetic acid:
in the first place, it seems to me that the milk globules are too small to
allow of the determination of the point in question with any degree
of certainty ; and, secondly, that in those instances in which observers
might fancy that an escape of the included substance of the globule
through its envelope had really occurred, such an appearance is, in
all probability, due to the adhesion together and partial fusion of two
or more globules. (See Plate XV. fig. 4.)
* Henle, Anat. Gen. p. 521, 522.
200
ORGANIZED FLUIDS
There are other observers again — as Wagner, Nasse, arid
QueVenne — who would deny to the milk globule all organization, and
who regard it as of a perfectly homogeneous nature.
The truth in this instance, as in so many others, would appear to
lie in the mean. That the milk globule is not provided with a
distinct and separate membrane, similar to that of the mucous
corpuscle, is proved by the impossibility of demonstrating the existence
of any such structure, as well as by the absence of a double line
around its margin, the non-effect of iodine, and the coalition of the
globules resulting from pressure, first observed by Dujardin.
That it is not constituted of a single perfectly homogeneous
substance, is also demonstrated by the observations of Mandl and
Henle, and especially by those of the latter observer on the effects
produced by acetic acid.
That the milk globule is not wholly composed of fatty matter, is
shown by its insolubility in boiling water raised to a very high tempera-
ture, in boiling alcohol, in the alkalies, and by the effects of the
application of acetic acid. Ether dissolves the milk globules : their
solution, however, it does not entirely accomplish on its first applica-
tion, although the ether, the moment it comes in contact with the
globules, causes them to lose their rotundity, to fall down, and to run
together into masses of various sizes, but most of which still present
a circular outline.
If a drop of milk be examined microscopically, after its treatment
by ether, a hasty observer might conclude, from noticing so many of
the circular masses alluded to, that the reagent had not exerted any
influence on the milk globules, and that these masses were the
unaltered globules. This view, however, a little reflection would
soon show to be incorrect; for many of the circular bodies now
noticed on the field of the microscope are larger than even the largest
milk globules, and all of them are flat and semi-fluid. (See Plate
XV. fig. 3.)
The several facts now adduced, while they prove that the milk
globule is not organized in accordance with the interpretation of the
.word organization usually given, yet seem sufficient to establish the
fact that it is composed of two distinct organic products — the one
internal and fatty, and the other external, and possessed of properties
distinct from fat.
This explanation of the constitution of the milk globule serves to
explain also satisfactorily the facts above alluded to, viz: the non-
MILK. 201
action of boiling water, alcohol, and alkalies, all of which affect more
or less fat, as also the slower operation of the ether: it also shows
why boiling alcohol should immediately dissolve the milk globules,
to which a little acetic acid had been previously added, this latter
reagent first removing their outer coating, which is insoluble in alcohol.
Between the globules of the previously-described fluids — those of
the lymph and chyle, of the blood, mucus and pus, and globules of
milk — no structural or functional relation whatever exists ; the former
being complex and definite organizations or cells, and the latter
constituted of two distinct substances indeed, yet want entirely the
attributes of cells, being destitute of nucleus and cell wall.
It is of the globules just described that the cream is constituted,
their accumulation on the surface of the milk being due to their
lighter specific gravity; it is also by their incorporation with each
other, and which is effected by the operation of churning, that butter
is formed.
COLOSTRUM.
The milk which is secreted the first few days after child-birth has
been denominated colostrum : it differs very considerably from
ordinary milk, being of a yellow colour, of a viscous consistence,
and containing a very large proportion of milk globules, which give
rise to the formation upon it of a thick layer of cream; when treated
with ammonia, it becomes glairy and tenacious.
Corresponding with the outward characters of the colostrum, there
are others indicated by the microscope not less remarkable : thus, the
larger true milk globules which occur in it are but ill-defined, being
irregular in form and size, appearing as though they were but imper-
fectly elaborated, and presenting rather the aspect of oil globules,
while the smaller ones are like a fine powder strewn through the
serum, and adhering to the surface of the larger globules, which also,
in place of floating freely and separately in the serum, are agglomer-
ated together as if held in union by some viscous material. (See
Plate XIV. figs. 4 and 5.)
But besides the state of the ordinary milk globules just described,
there are found in the colostrum peculiar corpuscles of a totally
distinct structure : these were first discovered and described by M.
Donne, who has denominated them " Corps granuleux."
These corpuscles are mostly several times larger than the milk
globules, are less regular in form, although usually more or less
202 ORGANIZED FLUIDS.
spherical in outline, and present a uniformly molecular aspect and a
yellow coloration; the edges of the corpuscles sometimes appear
smooth, as if possessed of an envelope ; at others, their margins are
rough, and convey the impression that they are destitute of any
external covering. See Plate XIV. figs. 3 and 4.) Occasionally one
or more milk or oil globules are imprisoned in the substance of the
corpuscles, which then occupy the position, although they do not
discharge the office, of a nucleus.
Some difference of opinion is entertained respecting their intimate
structure: Gueterboch, and probably Donne,* conceive that they are
furnished with an investing membrane, and therefore that they are
veritable cells, while Henlef regards them as masses or aggregations
of granules agglomerated together in an amorphous and mucoid
substance ; an opinion in which I concur.
Donne states that the colostrum corpuscles are soluble in ether, and
therefore that they are of a fatty nature : the fact of their solubility,
however, seems to me to be difficult to verify ; and from observations
which I have made, I cannot help thinking that this point is scarcely
as yet established. Certain it is that corpuscles larger than mucous
globules, and in every way similar to the colostrum corpuscles, save
that traces of nuclei may be detected in them, appear in colostrum
treated with ether.
The " Corps granuleux " are insoluble in the alkalies, J are coloured
brown by iodine, and the substance which unites the granules is
dissolved by acetic acid.§
The state of the milk just described does not continue without
alteration, each condition which has been alluded to undergoing a
daily modification : thus the milk globules from day to day acquire
greater uniformity of size and shape, they no longer adhere together,
but float freely and singly in the serum, which does not become viscid
on the addition of ammonia, the smaller dust-like globules also
altogether disappearing ; at the same time the number of the colostrum
corpuscles diminishes until at length none exist. (See Plate
XIV. fig. 1.)
These several changes are all accomplished in the course of a few
days, so that by the end of the twenty-fourth day, the milk has
usually entirely passed from the condition of colostrum, and presents
only its ordinary characters. The colostrum, however, does not
* Cours de Microscopie, p. 401. f Anal. Gen. t. vii. p. 525.
J Donne, loc. cit. p. 401. JHenle, loc. cit. t. vii. p. 525.
MILK. 203
always pass through its various modifications in the time specified ; it
may do so in either a shorter or a longer period than that stated:
thus, the existence of the milk in the form of colostrum can scarcely
be regarded as affording any very certain test whereby the age of
the milk may be determined.
The colostrum corpuscles would appear to be almost peculiar to
the human subject, for while their presence in the milk of woman is
almost constant, their occurrence in that of animals — as the cow, the
ass, and the goat — i%rare and exceptional.
Professor Nasse states that they disappear sooner in women who have
borne many children than in those who have had but a single child.
Mucous corpuscles are also occasionally encountered in the colos-
trum. They are, however, neither very generally present, nor do
they occur in any very great numbers.
The colostrum, or first milk, is possessed of purgative qualities.
PATHOLOGICAL ALTERATIONS OF THE MILK.
Persistence of this Fluid in the condition of Colostrum.
It has been stated, that usually by the end of the twenty-fourth
day after child-birth, and frequently at a much earlier period, the
colostrum has lost all its distinctive characters, and the milk has
arrived at its perfect condition.
This transformation of the colostrum into fully- elaborated milk, it
has been observed, is not always effected in the time named : it may
be accomplished in either a shorter or a longer period ; thus, the milk
in some cases loses the chief characters of colostrum in as short a
space of time as three or four days, while in others it retains them for
months after the birth of the child, and even until the end of lactation.
This persistence of the milk in the state of colostrum may be
present without any suspicion of its existence being entertained, the
milk exhibiting its ordinary outward appearances.
It is, therefore, only by means of the microscope that its true
condition can be ascertained. Examined with this instrument, the
characteristics of colostrum will be detected ; thus, the globules which
do not float freely in the serum, and which are large and ill-formed,
will be seen to adhere together in groups, as though held in union by
some viscous substance, and intermixed with them will be noticed
numerous colostrum corpuscles.
It cannot be doubted but that such persistence of the milk in the
form vi colostrum exerts a most injurious effect upon the child : the
204 ORGANIZED FLUIDS.
colostrum is, as we know, possessed of purgative properties; these,
during the first days of the life of the infant, are necessary; their
continuance cannot but impair its strength and health.
Recurrence of Colostrum.
M. Donne has established the interesting fact that milk which has
entirely lost the character of colostrum, and which has reached its
perfect maturity, may again pass into the state^of colostrum at any
period during the course of lactation.
Thus, the milk which had at one time presented the constitution of
perfectly formed milk has been seen by M. Donne to acquire gradually
that which is indicative of the colostrum, it becoming viscous, and
the globules contained in it, instead of floating freely and singly in
the serum, uniting with each other, forming irregular masses, the
granular and mucous corpuscles at the same time being present in it
in considerable quantities.
In the instances in which the recurrence has been observed,
engorgement of one or both of the mamary glands has usually
preceded it.
When but one gland is affected, the milk of that gland only presents
the characters of colostrum, that of the opposite side retaining its
usual properties and constitution.
The recurrence of the colostrum would appear to depend, as a
cause, either upon lesion of the mammary gland, or upon a deranged
or vitiated condition of the health.
Influence of prolonged Retention of the Milk on its Constitution.
M. Peligot has made the observation, important in a practical point
of view, that the milk which has been allowed to remain for a long
time in the breast becomes thin and watery, an effect which is
contrary to that which occurs in reference to most other secretions
of the economy, the urine and the bile, the density of which is
heightened by retention.
Thus, if the milk abstracted at one time, and which has been long
secreted, be divided into three parts, each being received successively
into a distinct vessel, the first milk will seem to be poor and watery,
the second more rich, and the third the most so of the entire. The
first portion is to be regarded as that which has been longest formed,
and the third as the most recently secreted.
MILK. 205
The knowledge of the above fact leads to one practical result in
the case in which the milk is too rich for the digestive powers of the
child ; thus by allowing such milk to remain for a longer period than
usual in the breast, a fluid of lighter quality and less abounding with
nutritive principles will be obtained.
A second effect of prolonged retention or engorgement of the milk
in the breast is to occasion the aggregation of the globules into
masses. (See Plate XIV. fig. 6.)
Pus and Blood in the Milk.
Having now described those constituents by the combination of
which milk is formed, as well as the several conditions in which
these may be encountered, we may next refer to those structures
which occasionally occur in milk as the result of disease.
Thus, the corpuscles of both pus and the blood are sometimes
encountered in the milk, those of the former fluid occurring much
more frequently than those of the latter.
The puriform matter which issues from the breast in cases of
abscess of that gland is made up of a mixture of pus and milk glo-
bules, with occasionally blood discs. (See Plate XV. fig. 1.)
But both pus and blood corpuscles* the latter very rarely, may be
contained in the milk which issues from the breast through its natural
channels.
I was so fortunate as to meet with an excellent example of blood
in the milk, the occurrence of which is so rare that Donne, at the
period of the publication of the " Cours de Microscopie," and with
all his researches on the milk, had never encountered a single instance
of such pathological alteration in the human subject. The case in
which this occurred was that of a young woman confined of her first
child ; the milk not appearing at the usual time, the friends became
anxious, and one of them, more officious and more ignorant than the
rest, had the nipples drawn with such vigour and effect as to cause
the extraction of a liquid half blood and half milk. (Plate XV. fig. 2.)
The occurrence of blood corpuscles in the milk can only take place
as the consequence of a rupture of some of the smaller blood vessels
which are distributed through the mammary gland.
The above facts clearly show the impropriety of applying an infant
to the breast in cases of inflammation and suppuration in that organ.
Not the least difficulty need be experienced in the detection of pus
and blood corpuscles in the milk, their form and structure being so
206 ORGANIZED FLUIDS.
totally dissimilar to those of the proper milk globules. Reagents
also affect the different kinds of corpuscles differently. Thus, the
milk globules are soluble in ether, which does not materially affect
the pus and blood corpuscles, the latter of which is dissolved by
acetic acid, and the former only by the caustic alkalies.
The Milk of Syphilitic Women.
M. Donne has made repeated attempts to discover in the milk of
women labouring under syphilis, in different forms, some element
which would account for the transmission of the affection from the
mother to the infant. These endeavours were, however, entirely
fruitless ; nor is this result other than what might have been antici-
pated, for it is scarcely to be supposed that the venereal virus exists
any where in a tangible form ; and if it really does so, it would still
be a matter of impossibility to point out the channels by which any
solid matter could make its way through the system and mingle with
the secretion of the mammary gland.
The Milk of Women in the Case of the premature Return of their
Natural Epochs.
The milk of women in whom the natural periods have returned
during the course of lactation, has likewise been carefully examined.
Except in a single instance, however, it has not been found to present
any thing remarkable in its characters. In the case referred to, it
had degenerated to the condition of colostrum, and contained the
granular colostrum corpuscles.
THE MILK OF UNMARRIED WOMEN.
The breasts of many women who have not been married are fre-
quently found to contain an abundance of milk, and from those of
most, more or less of a milky fluid can be obtained.
This milk exhibits all the characters of colostrum, containing even
the peculiar corpuscles which distinguish that condition of the milk ;
it is therefore, like the first milk, to be regarded as an imperfectly
elaborated substance.
THE MILK OF WOMEN PREVIOUS TO CONFINEMENT.
The breasts of most women during the last few weeks of gestation
contain more or less milk, which also presents all the characters of
colostrum.
MILK. 207
The quantity of milk contained varies greatly; in some cases a
few drops of a milk-like fluid only can be obtained ; in others it is
more abundant ; and again, in other instances, it is still more plentiful,
and rich in quality.
The question may be asked, does there exist any relation between
the quantity and condition of the milk before confinement, and its
state when it has arrived at perfection after this event has occurred ?
In other terms, can one pronounce, by the milk in the breasts, before-
hand, whether a woman will have a sufficient quantity of milk to
nourish her infant ?
This question, which so often presents itself to the consideration
of the medical practitioner, M. Donne has discussed at some length,
and to it he replies thus :
" The secretion of the mammary gland," he says, " is after con-
finement in constant relation with the state which it presents during
gestation, so that it is possible to know in advance, by the observation
of its characters during the last months of pregnancy, what its
condition will be when it shall have acquired all its activity after
parturition."* This law, he states, is so general, that in the sixty
observations which he has made on women of all ages and tempera-
ments, he has met with but two or three exceptions.
Pregnant women Donne divides into three classes, founded upon
the characters presented by the colostrum during the last months of
gestation :
1st. Those in whom the secretion is small, and the viscous liquid
contains scarcely any milk globules, mixed with a very few colostrum
corpuscles.
2d. Those in whom the colostrum is more or less abundant, but
poor in milk globules, which are small, ill-formed, and containing
also colostrum and mucous corpuscles.
3d. Those in whom the colostrum is very abundant, rich in milk
globules, which are of good size, and unmixed with any other cor-
puscles save those proper to the colostrum.
Now, the indications to be deduced from the different states of the
colostrum just described are —
That the first state appertains to women in whom the secretion of
milk after child-birth is either very little, or in whom there is pro-
duced but a serous milk, poor in nutritive elements, and therefore
insufficient for the nourishment of the child.
* Cours de Microscopk, p. 406.
208 ORGANIZED FLUIDS.
That the second condition indicates those in whom tne secretion
of milk after confinement is either small or abundant in quantity, but
which is always poor and serous.
That the third state of the colostrum belongs only to such women
as have an abundant supply of milk of good quality.
THE MILK OF WOMEN WHO HAVE BEEN DELIVERED, BUT WHO HAVE NOT NURSED
THEIR OFFSPRING.
The mammary gland of women who have borne children, but who
have not nursed them, is frequently found to contain milk many
months after confinement.
This milk always presents the characters of colostrum.
MILK IN THE BREASTS OF CHILDREN.
A milk-like fluid can frequently be expressed from the breasts of
infants and young children, both male and female.
This fluid, examined microscopically, has been found to exhibit all
the characters of ordinary milk; and, in some cases, the colostrum
corpuscles have even been detected in it.
DIFFERENT KINDS OF MILK.
The milk of one mammiferous animal resembles so closely that of
another that it is often a matter of impossibility to distinguish, either
with the naked eye or by means of the microscope, the different kinds
of milk.
The milk of the ass may, however, be generally known by its
watery aspect, its bluish tint, and its lightness; that of woman by the
promptitude with which the layer of cream is formed upon it; but it
is, above all, by the taste that the several kinds of milk are charac-
terized : thus, the taste of the milk of the cow can scarcely be con-
founded with that of the ass or goat, nor can the flavour of the milk
of woman be mistaken for that of any of these.
The microscope aids but little in the discrimination of the different
kinds of milk: the globules of the milk of the goat are certainly
smaller than those of the other species named, and those of the ass
are less numerous; nevertheless, these characters are so little con-
stant that they are not, in many instances, sufficient to distinguish
them from the milk of the cow or of woman.
The number of globules contained in the milk of different animals
doubtless varies considerably; but there is as much variation in this
MILK
209
respect as in those just referred to; and, therefore, this difference is
not sufficient to distinguish the several kinds of milk.
RELATIVE PROPORTIONS OF THE ELEMENTS OF MILK.
Chemical analysis indicates a very great variety in the relative
proportions of the different nutritive ingredients of milk; and this, not
merely with respect to the milk of different animals,, but also in refer-
ence to that of the same species, and even of the same individual, at
different times.
The truth of these remarks will be evident from an examination of
the following analyses :
Analysis of the Milk of Woman, by Peyen.
Butter, - - - - 5-16
Sugar and cream, - - - 7 ' 80
Analysis of the same, by F. Simon.
Water, ....
Caseine, ....
Sugar, ....
Butter, — -
Salts, extractive matter, &c,
88
06
3
•70
4
54
3
40
0
30
100
00
Analysis of the Milk of Woman, the Cow, the Goat, and the Ass, by Meggenhofen,
Van-Stiptrian, Liuscius, and Bonpt, and Peligot.*
Woman.
Cow.
Goat.
Ass.
Butter,
8-97
2-68
456
1-29
Sugar,
120
5 68
9 12
6-29
Caseine,
1-93
895
4-38
1-95
Water,
87-90
84'69
81-94
90-95
It will be seen from the above analyses that the milk of woman is
the richest in butter, while that of the ass contains the smallest
amount of that element.
The assertion made by Donn&, that the quantity of butter in the
milk of the same species stands in relation with that of the other
essential ingredients of the milk, although supported by the researches
of Peyen and Peligot, is contradicted by those of F. Simon. Accord-
* This analysis is copied from the Cours de Microscopie of Donne.
14
210 ORGANIZED FLUIDS.
ing to the analyses of Simon, the quantity of sugar is greatest imme-
diately after delivery; a few days being passed, this diminishes, and
the amount of caseine, which was at first very small, undergoes a
gradual augmentation. The butter Simon considers to be the most
variable element of the milk, its variations not being reducible to
any law.
The relative proportion of the different ingredients of the milk of
animals may be modified, and almost altered, at will, by the adoption
of a certain regimen.
GOOD MTT.V.
The purity and the richness of milk were formerly estimated by its
specific gravity, which is about 1 '032; if the milk was poor in cream,
or if it was diluted with water, it was supposed that the gravity of the
fluid would be in the first case increased, and in the second lessened.
The cream being the lightest element of the milk, its deficiency or
its abstraction would, of course, increase the density of the remaining
fluid, and the addition of water, after the removal of the cream, which
is also of less weight than milk which is even pure and rich, would,
of course, raise the gravity of the milk either up to or even beyond
its natural weight.
Now, the abstraction of the globular element of the milk and the
addition of water are the two frauds most frequently had recourse to;
and they are of such a nature as to elude detection by reference to
the specific gravity of the milk, when they are both put in practice
in combination.
The specific gravity test of the purity and richness of milk is, then,
one which is fallacious, and therefore but of very little value.
It has been proposed by M. Quevenne, not merely to estimate the
specific gravity of milk, but also to measure the layer of cream which
forms upon it by repose. This ingenious method is scarcely more to
be depended upon than the preceding, and is put at fault by the fact
that the addition of water favours the ascension of the cream.
Thus, the layer of cream formed on milk to which water has been
added will be thicker than that of unadulterated milk, this effect being
the consequence of the lessened specific gravity resulting from the
addition of the water.
Donne has made the statement, which is borne out by the analyses
of MM. Peyen and Peligot, that the globular or buttery element of
the milk stands in relation, in the milk of the same species of animal,
MILK. 211
though not in different species, with the other nutritive ingredients of
milk, the cheese and the sugar. The analyses referred to are the
following :
Milk of Woman, analyzed by M. Peyen.
Butter, - - 5-16 5-18 5 20
Sugar and cheese, 7 • 80 8*10 9 ■ 80
Milk of Asses, analyzed by M. Peligot.
Butter, - - 1-55 1-40 1'23 1'75 1-51
Sugar and cheese, 10 '11 7 '97 7 34 8"25 7 -80
Donne, therefore, proposes to estimate the purity and the richness
of milk by means of the globular element contained within it. The
eye alone will, in some measure, indicate the number of globules con-
tained in the milk; for, since the opacity of milk is due to the presence
of the globules, it may be concluded that the milk which is white and
opaque is rich in globules, while that which is watery and transparent
is poor in the same.
The microscope, however, is a more certain means of determining
the number of the globules, although by means of this instrument we
can only arrive at an approximative knowledge of their amount.
In order to estimate as nearly as possible the number of globules
existing in the milk, M. Donne has invented an apparatus which he
has termed a lactoscope. By means of this instrument, the milk can
be examined in very thin layers ; and in proportion to the opacity of
the milk spread out in such layers, so will be its richness — the deeper
the stratum, the richer the milk.
There is one fallacy attending the use of this instrument which
requires to be noticed; this, however, is one which has reference to
its employment in testing the quality of the milk of the cow, the ass,
and the goat, and not of the milk of woman.
The milk of commerce is frequently adulterated with substances,
such as chalk and flour, which are intended to heighten its colour
and opacity ; the presence of these then in the milk would, to a cer-
tain extent, lessen the value of the opinion to be deduced from an
examination of the milk with the lactoscope of Donne.
The effect, however, of the admixture of chalk and flour, in height-
ening the opacity of milk, is not so considerable as might be supposed,
and this is especially found to be the case when it is spread out in thin
212 ORGANIZED FLUIDS.
layers, as in the lactoscope. Moreover, the presence of an insoluble
substance in the milk might be detected by means of the microscope.
Applied to the examination of the milk of woman, the lactoscope
would not be subject to the above fallacy.
Having now shown that the globules constitute an important ele-
ment of the milk, and the methods by which their number may be
ascertained, we may, in the next place, describe more particularly the
qualities of good milk.
Healthy milk may be defined to be an alkaline fluid, having a spe-
cific gravity of about 1 : 032, holding in suspension numerous perfectly
spherical and discrete globules, soluble in ether, and therefore of a fatty
nature ; and, in solution, cheese and sugar, together with various salts.
If, on the contrary, the milk be viscous or acid — if the globules be
ill-formed or few in number — if they adhere together in masses, and
do not roll freely and separately in the serum — if also this contain the
colostrum corpuscles — then the milk is either imperfectly elaborated
or diseased.
Whenever the proper globules of the milk occur abundantly, are of
the usual size, and are equally diffused throughout the serum, we may
conclude that the other nutritive elements of the milk are likewise
present in due proportion. (See Plate XIV. fig. 1.)
It must be held in mind, however, that the milk of different animals
does not contain normally the same relative amount of nutritive
ingredients: thus, the milk of woman is especially rich in cream,
while that of the goat and ass is but poor in that element.
POOR MILK.
Not unfrequently the milk is found to contain a less quantity of
globules than ordinary : the milk in which a deficiency of its globular
element exists appears watery and transparent, and is also usually of
greater specific gravity than good milk. (See Plate XIV. fig. 2.)
This condition of the milk is one of its most common as well as
most serious states in its consequences to the child.
At the same time that the milk is poor in globules or in cream, the
serum may be either deficient in quantity, or it may be in excess.
In either case, such milk, whether it be human or not, is deficient
of the amount of the nutritive ingredients necessary for the growth
and development of the child, which, instead of increasing in size,
daily diminishes, becoming faded and emaciated. In the instances in
which milk containing a super-abundance of serum is received into
MILK. 213
thj stomach, that organ becomes distended and weakened by its
engorgement with a fluid, the digestion of which brings with it little
or no nourishment.
An infant whose strength is reduced by the poverty of the milk
given to it, is not unfrequently the subject of diarrhoea, which still
further lessens its powers.
An opposite condition of the milk to that just described frequently
exists, viz : that in which its nutritive principles are in excess, a fact
which is most readily ascertained by an examination of the state of
the globular element of the milk: this being super-abundant, it may,
as already shown, be concluded that the sugar and cheese likewise
occur in unusual quantities. (See Plate XIV. fig. 5.)
This condition of the milk is not to be regarded as an alteration
of its qualities, but merely as an exaggeration of them ; nevertheless,
it is one which is often incompatible with the well-being of the child.
This rich milk is often too strong for the digestive powers of the
child, whose nutrition in consequence suffers: it, moreover, is some-
times the occasion of colic and diarrhoea.
The state of the milk just noticed, and its consequent effects upon
the child, may be modified, and even entirely remedied, by a judicious
regulation of the diet, as well as by permitting the milk to remain in
the breast for a considerable time, the effect of which retention is to
render it more watery; the infant, also, should not be allowed to take
the breast except at long intervals.
At the same time that the globules are more numerous in milk
which is rich, they are also larger. The size of the globules is like-
wise found to undergo an increase from the first days of lactation,
and this increase continues for some months afterwards : thus, the
globules of the third month are larger than those of the first month,
and those of the sixth month still larger, the number of the very
small globules having diminished very considerably. The increase
in the size of the globules referred to, is not, however, so uniform or
so constant as to allow of the determination from it of the age of the
milk.
ADULTERATIONS OF MILK.
There are but few articles of general consumption more adul-
terated, and on which more frauds are practised, than the milk.
The more usual substances employed for the purpose of adultera-
214 ORGANIZED FLUIDS.
tion are water, flour or starch, chalk, and the brains of sheep; of
these, water is the one which is most frequently had recourse to, and
which is the most difficult to detect.
The effect of water in altering the specific gravity of milk has
already been referred to ; and it has been shown that the result of its
addition to milk, a portion of the cream of which has been abstracted,
is to restore the specific gravity which usually belongs to it.
Donne has shown that, however much the gravity of milk may
vary, the density of the serum of the milk is almost constant. This
fact is interesting and important; for, by a knowledge of it, the dete-
rioration of milk by its admixture with water, or with some other
substance of the same density with it, may be ascertained. The
serum is constantly heavier than water; adulteration with it would
then cause the serum to exhibit a less specific gravity than that
which should properly characterize it; the conclusion to be deduced
from this circumstance being that the milk has been deteriorated,
most probably, by the addition of water.
The adulterations with flour and sheep's brains are readily detected
by means of the microscope. The fraud by the former may be
recognised by the peculiar form of the flour granules, as well as by
the action of iodine upon them (See Plate XV. jig. 6) ; and that by
the latter may be distinguished by the detection, in the fluid, of more
or less of cerebral structure, and especially of the nervous tubuli.
The chalk in the milk is readily revealed by its effervescence with
hydrochloric acid, as well as by its weight, which causes it to subside
at the bottom of the vessel containing the milk.
FORMATION OF BUTTER.
Several explanations have been proposed with the view of deter-
mining the exact cause of the amalgamation of the cream globules
with each other, and the formation of butter.
Some have supposed that the trituration to which the globules are
subject in the churn, determines their union and incorporation with
each other ; but it is known that the amalgamation is not a gradual
process, as it would be were their union to depend upon trituration,
but that it takes place in a manner almost instantaneous: moreover,
agitation might fairly be presumed to have a contrary effect on the
globules, which participate in the properties of oil, and that it would
cause their further sub-division.
A second hypothesis conceives that a chemical alteration in the
MILK. 215
condition of the globules is determined by the presence of the air:
this has been shown to be erroneous by the fact that butter will form
in vacuo.
A third theory presumed that an acid state of the milk always
preceded the formation of the butter : this notion is disproved, since
butter is formed of cream, the alkalinity of which is purposely pre-
served by the addition of soda or any other alkali.
Donne thus explains the formation of butter : " The butter glob-
ules," he says, "are surrounded in the cream by cheese in a viscous
state: this matter isolates the globules the one from the other, and is
opposed to their union. The churning coagulates the cheese in
which the globules are imbedded, and, once separated from this, the
grease globules unite and agglomerate together easily."
It is doubtful how far this explanation, though more satisfactory
than its predecessors, really accounts foi\the instantaneous formation
of the butter.
MODIFICATIONS EXPERIENCED BY MILK ABANDONED TO ITSELF, AND IN WHICH
PUTREFACTION HAS COMMENCED.
The first change which the milk undergoes, subsequent to its
abstraction from the system, is that which has already been referred
to, and which consists in the separation of the globular or buttery
element of the milk from its other constituents, and its ascension to
the surface of the fluid, where it forms the layer of cream; this
change in the arrangement of the components of the milk is deter-
mined by the lighter specific gravity of the proper milk or butter
globules.
All the milk globules do not, however, ascend and join those which
constitute the cream : it is chiefly the larger ones which do so, the
smaller remaining diffused through the subjacent milk, to which they
impart the degree of opacity which belongs to it.
These smaller globules are not, however, equally scattered through
the skimmed milk, the greater portion of them being spread through
the upper stratum of it, and the lower appearing almost clear and
transparent, containing but few butter globules, and these the smallest,
as well as the minute cheese globules already described.
These changes consist merely in a different disposition of the
normal constituents of milk, and are unaccompanied by any alteration
in the constitution of its elements. The next series of alterations
have reference to the decomposition of the milk, and are attended by
changes in the actual state and composition of the milk.
216 ORGANISED FLUIDS.
The first change experienced by the milk, indicative of com-
mencing decomposition, is that from an alkaline to an acid condition.
This acidity, slight at first, goes on increasing, until at length other
alterations are produced; thus, the layer of cream becomes thicker
and thicker, condenses itself into a mass, and finally presents almost
the appearance of butter; at the same time the cheese is coagulated,
and precipitates itself to the bottom of the liquid: a portion of it,
however, frequently remains suspended in the milk, in consequence
of its retaining a number of butter globules, which lessen its specific
gravity. Soon, however, other changes show themselves, still more
indicative of putrefaction: the layer of cream swells up, becomes
more yellow, and a fungus springs up upon its surface, the Penicillum
glaucum. This at first presents the appearance of white velvet ; but
afterwards, as soon as the fungus has reached the period of fructi-
fication, it assumes a green colour.
The idea of M. Turpin, that this fungus had its origin in, and was
developed from, the milk globule, scarcely requires a serious refutation.
At the same time, the odour of the milk undergoes a complete
change : sweet when it is fresh, it becomes acid as it decomposes, and
gives out more especially the smell of cheese.
Examined with the microscope, in addition to the fungus alluded to
above, numerous infusory animalcules will likewise be detected.
Now, the changes above described, and which are experienced by
the milk of every animal, will be more clearly understood if the milk
be previously filtered, and the butter and the serum being obtained
separately, those alterations which ensue in each be noticed.
It will be observed, that it is the butter, or non-azotised substance,
which undergoes the acid fermentation, and on which the fungi are
principally and most generally developed.
The serum, on the contrary, becomes alkaline, and exhibits the
ammoniacal or putrid fermentation, this depending upon the azotised
principle which it holds in solution, viz : the cheese.
It will be remarked, also, that the serum, in changing, does not
exhibit the striking odour of cheese which the milk itself gives out
under the same circumstances, and from which it may be concluded
that a certain amount of butter is necessary to produce the peculiar
smell of cheese.
The phenomena to which the putrefaction of milk give rise result,
then, from two kinds of fermentation ; the acid, in which the buttery
element of the milk is concerned, and the alkaline, resulting from the
decomposition of the caseine.
MILK. 217
THE OCCURRENCE OF MEDICINES, ETC., IN THE MILK.
The extreme rapidity with which the formation of milk from the
blood is effected is most surprising, and is only equalled in the animal
economy by that with which the urine is itself secreted.
The rapid secretion of milk from the blood serves to explain the
almost immediate appearance in the former fluid of various chemical
reagents and articles of food introduced into the system through the
medium of the stomach.
Thus, many articles taken as food, or as medicine, have been
detected in the milk a few minutes after they have been received into
the stomach. The colouring matter of madder-root, the odorous
principles of garlic, turpentine, &c. — neutral salts, nitrate of potas-
sium— have all been encountered in the milk.
These particulars show the necessity of great precaution in the
prescribing of remedies for a nursing mother, and explain the great
susceptibility of children at the breast to the influence of the medicine
administered to the parent.
[Farther than the directions already given for the examination of Lymph,
Chyle and Blood, it is not thought necessary to add any instruction for the
study of the fluids just treated of, the manner of preparation and examina-
tion being precisely the same, and the different reagents most striking in
their effects having been fully indicated in the text.
The preservation of most of the fluids will be found a difficult matter, as
most of the preservative solutions employed would so act on the constituents
of each fluid, as to render them comparatively useless. The corpuscles of
the blood are easily preserved in the manner indicated at the close of the
chapter on that subject.
Those of lymph, chyle, mucus, pus, and milk, are best preserved in the
flat cell with the naphtha-water, or with Goadby's B-solution, in the manner
already indicated in the chapter on preservative fluids.
With all possible care, however, these preparations will soon lose their
value, as the corpuscles will undergo more or less change, and therefore
cease to have the same characters, as fresh specimens of the same fluid.]
218 ORGANIZED FLUIDS.
ART. VI. — THE SEMEN.
The seminal fluid, arrived at its perfect state, as when it is ejacu-
lated, is not a simple liquid, the secretion of a single organ, but is
compounded of the several products furnished, though not in an equal
proportion, by the testicle, the epididymis, the vas deferens, the pros-
tate gland, the glands of Cowper, the vesiculae seminales, and the
follicles of the urethra.
But the spermatic fluid is also in another sense a compound pro-
duct; thus, like the fluids which have already been described, it is
made up of a liquid and a solid element, the latter consisting of
numerous organized particles suspended in and diffused through the
former ; these particles are of more than one kind, and may be divided
into those which are essential and those which are non-essential:
those which belong to the first category are the spermatozoa, the sem-
inal granules, and the spermatophori; and those which appertain to
the second, are the mucous corpuscles and epithelial scales : these last
constituents occur but seldom, and are difficult to discriminate from
the seminal granules and the spermatophori.
The spermatic fluid, resulting from the above combination of solid
and fluid elements, is then usually a thick semi-opaque and gelatinous-
looking substance, of a grayish, whitish, or yellowish tint, and endowed
with a peculiar and penetrating odour, which Wagner states does not
belong to the sperm previous to its departure from the testicle itself.
It is, above all, the spermatozoa, from the liveliness of their
motions, the variety of their forms, the peculiarity of their develop-
ments, and their functional importance, which impart interest to the
study of the spermatic fluid, and which the microscope has shown to
occur in it in such vast numbers.
SPERMATOZOA.
The spermatozoa* are the most distinctive, as well as the most
interesting, constituent of the semen, and once detected, the nature
of the fluid under examination can no longer be doubted.
*In reference to the discovery of the spermatozoa, the following passages are con-
tained in Leeuwenhbek (Opera, t. iv. p. 57) : "N. Hartsoeker (Prccven der Doorsich-
ikunde, s. Specimina dioplrices, p. 223) says that he made known the spermatic
animalcules in 1678, in the "Journal des Savants." I attribute the discovery to
THE SEMEN, 219
Each spermatozoon consists of two portions, an expanded part, to
which has been assigned the several names of "disc,"' "head," and
"body," and an attenuated extremity, which is called "tail."
The spermatozoa present great varieties in size and form: these
variations are, for the most part, constant in a natural family and
genus, and are always so in a simple species : thus, a knowledge of
the particulars of form and size of the seminal animalcules is fre-
quently sufficient to distinguish many groups, genera, and individuals
from each other: spermatozoa are, therefore, capable of affording
assistance in classification.
Form.
In the class Mammalia especially, with which, in this paper, we are
chiefly concerned, the spermatozoa vary greatly in shape; but in sev-
eral of the more natural groups of that class, one determined form and
magnitude may be detected throughout the different species consti-
tuting such groups.
In man, and in some animals which approach near to man in their
organization, the spermatozoa are small, the head or disc is ovate, the
narrow extremity forming the summit of the disc, and the tail, pro-
ceeding from its broader end, diminishes in size from its origin to its
termination, which is so fine, that its extreme point can with diffi-
culty be discerned. (See Plate XVI. fig. 1.)
In the rat and m the mouse the seminal animalcules are large, and
their form peculiar ; the head is half sagittate, and moveable upon the
tail, which is long, and attached not to the base of the arrow-like
head, but to its side: frequently the head is curved, in which case it
resembles the blade of a curved cimeter. (See Plate XVII.)
In the guinea-pig, also, the magnitude of the spermatozoa is great,
and the shape remarkable : in this animal the head is large, ovate,
concave on one side, and convex on the other, the tapering and elon-
gated cauda arising from the narrow end of the oviform head, which
may be compared in form to a mustard-spoon. (See Plate XVII.)
Hamm. He brought me, in 1677, some gonorrhoea! matter, in which he found ani-
malcules with a tail, which, according to him, were produced by the effect of decom-
position. I afterwards examined fresh human semen, and I then perceived the same
bodies. They were in motion, but in the liquid portion; in the thick part they
remained immoveable. They were smaller than the corpuscles of the blood, rounded,
obtuse before, pointed behind, with a tail five or six times as long as the body."
The description of Leeuwenhoek appeared for the first time hi the Philosophical
Transactions, December, 1677, and January and February, 1678.
220 ORGANIZED FLUIDS.
In birds, two singular types occur, the one characteristic of the
order Passeres, the other typical of the Rapaces, Scansores, Gallince,
Gralla, and Palmipedes. In the first, the head of the spermatozoon
is elongated and spiral, resembling a corkscrew; the number of coils
and the acuteness of the angles vary in different species ; usually
two, three, or four turns are described; the attenuated and greatly
produced tail proceeds from the finer end of the spire, and between it
and the body no exact line of demarcation exists. (See Plate XVI.
Jig. 2.) In the second, there is a distinct division into head and tail,
and the former is elongated, as in the order Passeres; but, in place
of being spirally coiled, is straight; the tail, arising abruptly from the
body, is of great tenuity, of equal diameter, and the length exceeding
but little that of the body.
The various forms assumed by the spermatozoa among the other
vertebrate and invertebrate animals, it is unnecessary here to describe :
the shape of those, however, belonging to the Tritons and Salaman-
ders, from their great peculiarity, may be briefly noticed. At the
junction of the body and tail of each spermatic animalcule an enlarge-
ment exists, the excessively attenuated caudal extremity being curved
spirally round the body.
The effect of water in modifying the form of the spermatozoa is
remarkable, it frequently causing them, when applied in large quan-
tities, to coil up and form themselves into rings : this effect of the
application of water is supposed to depend upon some hygroscopic
property possessed by the spermatozoa.
Frequently the spermatozoa are seen to occur on the field of the
microscope, grouped together in bundles, the bodies all lying one way,
and fitting by their concavities into each other. (See Plate XVII.)
This arrangement, as will be seen hereafter, is connected with the
evolution of the spermatozoa.
Occasionally, in man and other animals, the head and tail are sepa-
rated from each other, and lie apart; this separation is doubtless
either the result of violence or the effect of decomposition. Henle*
states that he has seen the tail move independently of the head.
Size.
Much diversity exists in the size of the spermatozoa in different
animals, although but little difference can be detected in those of the
same individual. Wagner, however, has made the observation that
* Ajiat. Gen. p. 534.
THESEMEN. 221
their magnitude varies greatly in different individuals of the same
species. These variations are, however, of course, confined within
certain narrow limits. In the Mammalia, the spermatozoa of
man are among the smallest, while those of the guinea-pig and rat
are among the largest hitherto discovered. . In the birds the seminal
animalcules of the order Passer es are very large, and especially those
of the chaffinch.
Structure.
When first the spermatozoa were discovered, and their lively
motions observed, much reluctance was entertained to regard them
as independent animals or beings; and upon this point, even among
modern physiologists, there is still an absence of accord, some of
them attempting to explain the movements exhibited on purely
physical principles.
Not many years ago, a celebrated and talented continental observer
thus expressed himself, in terms more ingenious than accurate, in
reference to the nature of the spermatozoa:
"When we place upon the object-glass of the microscope the
semen of a subject who enjoys all the energy of his generative
faculty, we there see corpuscles more or less rounded or oval, having
a sort of caudiform appendix : some have made animalcules of these
little bodies, since they have seen that they move, and have believed
to have recognised in their movements a determined direction, a
character which they thought could only appertain to animated
beings. And as among the microscopic animalcules which they
knew there are those which are provided with a tail more or less
prolonged and more or less dilated, they have assimilated to them the
little animalcules of the semen, and have made them Cercarice.
"But you are about to see that the conformation and the move-
ments of the corpuscles in question may be explained naturally,
without our being obliged to have recourse to the hypothesis of which
I have spoken. It is certain that we find in the sperm little gelatini-
form masses, more or less rounded, oval, and having one part
prolonged into the form of a tail, like, in a word, to the drawings
which Buffon and many other observers have given us of the pre-
tended spermatic animalcules. These little masses float in a material
less consistent than themselves, and even fluid. But at first their
oval form results evidently from the manner in which they reflect the
222 ORGANIZED FLUIDS.
light, and afterwards as the fluid in which they are suspended — a fluid
which is itself more or less viscous — attaches itself strongly to them,
it results that in the microsco-chemical movements which take place
in the sperm, the corpuscles which it encloses seem to have a tendency
to escape from the kind of glutinous material which contains them.
This material, seeking, if we may express it thus, to retain them,
accompanies them to the situation only where they find themselves to
be arrested by a filamentous prolongation, which presents sufficiently
well the appearance of a tail, and even of a flexible tail, by reason of
the lateral movements which the little body makes in its progression.
There is merely in all this, as you see, a mechanical phenomenon, and,
in the movement which there takes place, but a physical effect of the
contact of two materials of different densities ; contact which pro-
vokes these materials to mingle together and to form but one, as
arrives at the end of a time more or less long. Abandon the semen
to itself, taking care that its watery part cannot evaporate by placing
it in an atmosphere saturated with humidity, at the end of a certain
time the mixture of the two materials will be complete, and you will
perceive no longer any thing but a homogeneous fluid; the pretended
animalcules have disappeared.
"If we wish to show you at the same time veritable microscopic
animalcules and the little gelatiniform masses which move in the
vehicle of the sperm, you will find a great difference between the
first and these last. I may fortify my opinion on this subject with
that of Buffbn and Spallanzani, who have denied that the masses of
which I speak wrere animalcules.
"Among the persons who have admitted the existence of these
beings, there are those who have carried their pretension so far as to
class them in genera and species by taking the form of the dilated
extremity for the principal zoological character. Some micrographers,
also, remarking the differences in the corpuscles of the sperm,
according as one procures this liquid from the testicle, the vesiculse
seminales, or after its ejaculation, have pretended, from that circum-
stance, to describe a series of evolutions in the development of these
so-called Cercarice. They have told us that these animals do not
exist in the product which occupies our attention at the moment that
it is formed; that they appear but in the vesiculae seminales; that in
these they are as yet but simple globular animals; that in their
progress they become developed by the production of their caudal
prolongations. Lastly, it has been pretended — doubtless with the
THE SEMEN. 223
design of marking with ridicule the opinions which we have reported —
it has been pretended, I say, that the spermatic infusorias became
among us, for example, veritable homuncules, having little arms,
little legs, &c. But this is sufficient in itself to put us on our guard
against an optical illusion which has unfortunately seduced a great
number of persons, from Leeuwenhoek, one of its first favourers, even
to MM. Prevost and Dumas, who in these latter days have still main-
tained the existence of the spermatic animalcules."
In the present day, it is needless to enter into any refutation of the
above views ; it cannot, however, fail to be observed by the reader,
that they are weakest just where they should exhibit the most strength,
that is, in the explanations given as to the form and motions of the
spermatozoa.
Those physiologists who deny the animality of the spermatozoa
would, of course, be very reluctant to admit of the existence of any
thing like organization in them; while those, on the other hand, who
entertained a belief in their animal nature, would be most anxious to
establish the fact of such organization.
The greatest possible difference of opinion, then, exists as to whether
the spermatozoa are organized or not, and, if organized, as to the
extent to which they are so.
In the centre of the disc of the spermatozoa of man and some
other animals a light spot has been observed ; this some have imag-
ined to be a stomach; others, again, have rejected this idea, and thus
account for its presence : the disc, they say, is not ot equal thickness,
and, like the red blood corpuscle, is thinnest in the centre, and which
part, therefore, exhibits a lighter tint than the remainder: this latter
view is most probably the correct one. The first opinion is enter-
tained by Valentin, and the second by Dujardin and Henle. Miiller
conceived the spot in question to be a nucleus.*
Leeuwenhoek remarked upon the spermatozoa of the ram two
clear spots; at another time, numerous little points in the interior; a
third time, two semi-lunar striae, united by a longitudinal line; he
figures also in those of the rabbit a multitude of little globules — one
of them, larger than the rest, being placed near the tail.
Gerber assigns a most complex structure to the spermatic animal-
cules of the guinea-pig, describing stomachs similar to those of the
poly gastric infusorise, an anus and sexual apparatus; and conceiving
*Muller's Physiology, p. 635.
224 ORGANIZED FLUIDS.
the existence of these several parts to have been established, he thus
expresses himself in reference to the nature of spermatozoa in general :
"The compound organization of the seminal animalcules and their
production by no equivocal generation, but in particular sexual
organs, and by the means of ova, to all appearance proclaim their
affinity to the Entozoa."*
Valentin f has described an almost similar amount of organization
in the spermatozoa of the bear: "The clear spermatozoa of the bear,"
he writes, "which in external form approach those of the rabbit,
present distinct traces of internal organization, to wit, an anterior
and posterior haustellate mouth, and internal cavities or convolutions
of an intestine."
Again, Dujardin J has described and figured certain irregular knots
and lobular enlargements at the root of the tail of the human sperma-
tozoa; these have been noticed by Wagner, who believes that they
occur only as the effects of certain alterations experienced by the
animalcules in consequence of their long stay in urine, and especially
when this fluid has contained at the same time a quantity of puriform
sediment.
Wagner likewise points out, as occurring now and then, but by no
means constantly, a small prominence or trunk-like process situated
on the anterior part of the body of human spermatozoa: this, or a
similar projection, he also states to be much more regularly present
in the seminal animalcules of the bat, in which they occur as pointed
spines. The same observer has, moreover, noticed upon one or two
occasions the caudal end of the body to be double, bifid, or forked,
and once too the body appeared to be double, as in a bicephalous
monster.§
The above comprise all the particulars which have hitherto been
promulgated in reference to the organization of the spermatozoa;
scarcely any one of them has, however, been sufficiently established :
we are therefore not authorized to receive them as proved, and to
build any reasoning upon them : the most which we are warranted
in deducing from them amounts to this, that traces of organization
have been discovered in the spermatozoa, the precise nature and
extent of which have not as yet been satisfactorily determined.
* Gerber's General Anatomy, translated by Gulliver, p. 337.
f Repertorium, 1837.
I Ann. des Sciences Nat. viii. p. 293. plate 9. 1827.
§ Elements of Special Physiology, pp. 10. 16.
THE SEMEN. 225
Notwithstanding his observations, given above, Wagner* states
that he has been utterly unable, after varied, repeated, and long-
continued examination, to discover true internal organs in the sperma-
tozoa. Sieboldf has also been equally unsuccessful in his endeavours
to detect such, as also HenleJ and Koelleker.
The determination of the fact that the spermatozoa are possessed
of even the smallest amount of organization, would involve their
classification in the animal kingdom, and the description of the
different forms which occur as so many distinct species.
The view of the animal nature of the spermatozoa would appear
to gather strength, and to admit almost of positive demonstration, by
reference to their very remarkable motions.
MOTIONS OF THE SPERMATOZOA.
It is impossible that any thing can convey a more just idea of life
than the spectacle of a drop of the seminal fluid in which the
spermatozoa are in active and ceaseless motion.
Sometimes, indeed, when the semen is thick and tenacious, the
movements of the contained spermatozoa are but feeble, the density
of the liquor seminis presenting too great an impediment to the free
motion of these minute creatures.
Often, however, in such cases, when the fluid has been diluted with
water or with some other liquid, as serum or milk, of less density
than itself, the spermatozoa, being now set at liberty, will frequently
be seen to resume their locomotive powers, and to move about with
the greatest activity. All the spermatozoa, however, contained in a
drop of semen which has undergone dilution will not start into
motion at once; many of them will remain for a time perfectly
motionless, and then suddenly, and, as it were, by an act of volition,
begin to move themselves in all directions.
Mode of Progression.
The motions of the spermatozoa are effected principally by means
of the tail, which is moved alternately from side to side, and during
progression the head is always in advance.
The strength of the spermatozoa is considerable, it enabling them,
when they are immersed in either blood or milk, to cast aside, with
* Loc. cit. p. 17. f Siebold in Weigman's Archiv. 1838.
\ Anatomie Generate, t. vii. p. 531.
15
226 ORGANIZED FLUIDS.
the greatest ease, the globules which may present themselves to
impede their progress.
The spiral spermatozoa of the Passeres advance by a movement
of rotation of the body, the tail remaining extended and motionless,
acting rather as a rudder than as an organ of locomotion. The
spermatozoa of the other orders of birds, and which consist of a
cylindrical body to which a short and attenuated tail is attached,
"scull themselves forward with their tails, either striking them slowly
and with wide sinuosities, or more quickly and shortly, as when a
whip is shaken ; they thus advance in circles with a quivering
motion, holding the body extended in a straight line, although they
also now and then bend this in various directions from side to side."*
The spermatozoa of the tritons and salamanders usually lie coiled
up in the form of a ring, and seem to spin round as upon a pivot ; at
the same time a second wavy and tremulous motion, like that pro-
duced by cilia, is observed; this arises from the rapid rotatory or
spinning movement of the very delicate tail with which the sperma-
tozoa of these animals are furnished, and which is wound spirally
round the body. Wagner at one time entertained the notion, which,
however, he subsequently discarded, that the wavy motion referred
to was produced by a ciliary apparatus. Sometimes the coiled
spermatozoa have been seen to unrol themselves and to cross the
field of the microscope with slow serpentine motions.
Furthermore, in the various motions executed by the spermatozoa,
they exhibit all the characters of volition; thus they move sometimes
quickly, at others slowly, alter their course, stop altogether for a time,
and again resume their eccentric movements. These movements it
is impossible to explain by reference to any hygroscopic properties
which may be inherent in the spermatozoa, they appear to be so
purely voluntary. A strong argument, therefore, in favour of the
independent animality of the spermatozoa may be derived from a
consideration of the nature of their motions.
Duration of Motion.
The length of time during which the motions of the spermatozoa
continue, either after the escape of the seminal fluid, or after the
death of the animal, varies very considerably; thus it is maintained,
for a longer period in warm weather than in cold, and when the
semen is retained within its natural reservoirs than when it is
* Wagner's Elements, p. 18.
THE SEMEN.
227
removed from those receptacles. The spermatozoa of some animals
also preserve their powers of locomotion for a longer period than
those of others ; thus, the seminal animalcules of birds die very soon
after the death of the bird; according to Wagner, frequently in from
fifteen to twenty minutes;* occasionally, nevertheless, the sperma-
tozoa have been found moving in birds which have not been opened
until some hours have elapsed after death: those of the Mammalia
have been observed in motion for a very long period after the removal
of the semen from the testicle, and after the death of the animal;
but it is in fishes that the spermatozoa retain their powers of locomo-
tion out of the body for the longest period, even for many days.
According to Dujardin,f the spermatozoa live thirteen hours in the
testicles of the mammalia after the death of the animal.
LamperhoffJ has found living semen in the vesiculse seminales of
dead men, in which the spermatozoa retained the power of locomotion
for twenty hours.
Wagner§ has observed them exhibiting motion at the end of
twenty-four hours.
Donn6|| states that he has watched their movements for an entire
day, and that he has observed them in motion even on the second day.
It is, above all, in the place of their final destination that the
spermatozoa live for the longest period ; thus, Leeuwenhoek first,
and other observers subsequently, have discovered them in a living
condition in the uterus and Fallopian tubes of a bitch seven days
after connexion,^! and Bischoff** has found them alive eight days
after intercourse in the rabbit.
The great length of time during which, under certain circum-
stances, the spermatozoa retain the faculty of locomotion, furnishes
another strong argument in favour of their independent vitality.
Effects of Reagents.
The seminal animalcules retain their locomotive powers for a very
long time in fluids of a bland nature ; for example, in blood, milk,
mucus, and pus ; on the contrary, in reagents of an opposite character,
and in those possessed of poisonous properties, they soon cease to
move : thus, in the saliva and urine, unless these fluids be very much
* Wagner, loe. cit. p. 21.
\ Diss, de Vesical. Semin.
II Cours de Microscopic, p. 284.
** Miiller, Archiv. p. 16. 1841.
f Annates des Sciences Nat.
5 Loc. cit. p. 22.
IT Opera Omnia, 1. 1. b. p. 150.
228 ORGANIZED FLUIDS.
diluted, their motions are soon destroyed, and immediately cease in
the acids and alkalies, in alcohol, iodine, strychnine, and the watery
solution of opium.
The addition of water to the spermatic animalcules usually pro-
duces a remarkable effect, increasing greatly for a time the rapidity
of their motions, which after the lapse of a minute or two entirely
cease; this reagent, as well as the saliva, exerts a further peculiar
influence upon them, causing them to curl up into circles or rings.
Poisons introduced into the system, and destroying the life, are
stated not to affect the motions of the spermatozoa; an assertion to
be received with some degree of hesitation : in cases of poisoning by
prussic acid, I have usually found the spermatozoa to be motionless,
even when viewed immediately after death.
The urine has the property of preserving the spermatozoa entire for
weeks and months ; and Donne1 has detected them in that fluid after
an interval of three months.
The result, then, of the application of reagents, furnishes an addi-
tional argument in favour of the animality of the spermatozoa, and
one which it would be difficult, if not impossible, satisfactorily to
controvert.
SPERMATOPHORI.
The only essential solid elements contained in the seminal fluid
arrived at its perfect state, as in the vas deferens, and when ejacu-
lated, are the spermatozoa; occasionally, however, there are encoun-
tered in it, as non-essential constituents, mucous corpuscles, epithelial
scales, and the seminal granules : the spermatic liquid, however,
obtained from the body of the testicle, contains not only the several
structures already named, but also minute and bright granules, and
the compound cells or sperm atophori, the bright granules and the
seminal corpuscles probably represent stages in the development of
the spermatophori.
The several structures now named are all occasionally met with in
the ejaculated semen; their occurrence in it is to be regarded rather
as accidental than as essential ; the spermatophori belong to the tes-
ticle, the tubuli seminiferi of which in many cases are almost filled
by them.
The spermatophori differ greatly from each other, both as respects
size and the number of secondary cells or nuclei contained within
them ; the smaller parent cells are about TJ\ o °f an mcn m diameter
THE SEMEN. 220
in man, and contain usually but a single nucleus, while the larger
ones attain the magnitude of j ±-q of an inch in breadth, and include
not unfrequently as many as six or eight nuclei, or, more properly
speaking, secondary cells. Between the two extreme sizes given,
every gradation presents itself, and many spermatophori contain but
one, two, three, or four nuclei, which are the numbers most frequently
encountered.
The secondary cells, like the primary or parent ones, are globular,
and those contained within the same parent cell are usually of the
same dimensions ; the centre of these cells occasionally presents a
bright spot. (See Plate XVI. fig. 1.)
Not unfrequently certain large and perfectly transparent cells are
encountered; these are, in all probability, the older spermatophori,
the contents of which have been discharged.
It would appear, therefore, that the development and dissolution of
the spermatophori are effected entirely within the tubes of the testes.
Cells, which Wagner has denominated seminal granules, occur, as
already remarked, mixed up with the undoubted spermatophori ; these
first are smaller, and do not contain nuclei; whether they are really
distinct from the latter, it is not easy to determine. If but one kind
of cell occurs in the testicle, then a double function must be assigned
to it : thus, in the first place, the secretion of the liquor seminis must
be effected by it ; and, in the second, the development of the sperma-
tozoa occurs within its cavity; in which case the spermatophori
would be the homologues of the cells of other glands, only in so far as
they discharge an analogous function, and are secreting organs ; in
the ulterior office allotted to them, that of being receptacles in which
the spermatozoa are evolved, they stand alone in the animal economy,
and are certainly without analogues in any other gland of the body.
It is most probable, however, that two kinds of cells coexist in the
testes — the one secreting and corresponding with the cells of other
secerning organs ; the other kind, of a peculiar nature, without par-
allel in the animal economy, and devoted to the development of the
spermatozoa.
DEVELOPMENT OF THE SPERMATOZOA.
Not the least interesting part of the history of the spermatozoa is
that having reference to their development.
Wagner was the first to state that the spermatozoa are developed
within the spermatophori just described.
230 ORGANIZED FLUIDS.
This interesting discovery of Wagner has been amply confirmed
by the extended observations of Kcelliker, Siebold, Valentin, and
Lallemand.
Wagner thus describes the evolution of the spermatic animalcules
in the spermatophori of a bird : " In the course of their development,
a fine granular precipitate is observed to form between the included
nuclei, by which these are first obscured and then made to disappear,
and linear groupings are produced, which anon proclaim themselves
as bundles of spermatozoa, already recognisable by slight traces of a
spiral formation of one extremity. (See Plate XVI. fig. 2, g.) It
were hard to say whether the fine granular precipitate is to be
regarded as the product of a process of resolution occurring to the
nuclei, or a new formation ; as, also, whether the spermatozoa spring
out of or only in and amidst the yolk-like matter, or matter that is at
all events comparable to the yolk of eggs in general. The vesicles
now assume an oval form (see Plate XVI. fig. 2, h), the globules dis-
appear, the granular contents diminish; the seminal animalcules are
well grown, and lie bent up within the cyst ; their spiral ends are
more conspicuous. The delicate covering (involucrum) is now
drawn more closely around the bundle of spermatozoa it includes, and
where it covers their spiral ends anteriorly it assumes a pyriform out-
line (see Plate XVI. fig. 2, i), and at the opposite extremity is perhaps
at this time open ; but it is difficult to speak decisively on this point.
The cysts are now very commonly bent nearly at right angles or like
knees, but at length they appear stretched out and straight, and have
attained their full size. (See Plate XVI. fig. 2, k.) The capsules of
these vesicles are at all times, and especially towards the end of their
existence, highly hygroscopic; the addition of a little water causes
them to burst, the masses of spermatozoa rolled up like a little skein
of thread or silk escape, and occasionally at this stage exhibit motions
individually, which, however, while the. animalcules continue in the
ducts of the testes, are frequently not to be observed, and are never
either general or remarkable. The spermatozoa, after the rupture of
the cyst, advance in freedom to the vas deferens."*
The process Wagner states subsequently to be precisely similar in
man and the Mammalia, although it is more difficult to follow it in
them.
The accuracy of the above account of the development of the
spermatozoa has been admitted by most other observers in all respects
* Translation of Wagner's Elements, by Willis, pp. 25, 26.
THE SEMEN. 231
save one important one: thus, Koelliker has shown that the evolution
takes place in the included or secondary cells, and not, as Wagner
describes it, in the spaces between these, a single spermatic animal-
cule being formed within each ; the granules enclosed in these cells
disappear gradually as the spermatozoon assumes a definite form, and
Koelliker further supposes that these granules constitute, by their union
with each other, the substance of the spermatozoa which escape from
both the secondary and primary cells by the rupture of their investing
membranes. When the spermatic animalcules have escaped from
the secondary cells, and these have disappeared, the spermatozoa form
a bundle which is still included within the larger primary cell ; some-
times the seminal animalcules are irregularly disposed within its
cavity, but more frequently they are applied directly to each other,
the heads lying one way, and the tails in the opposite direction. This
disposition of them is often preserved even after their escape from the
spermatophori, during their stay in which the spermatozoa usually
remain quite motionless.
The interesting and important fact of the development of the
spermatozoa in the secondary cells, or ova, as they should now be
called, Koelliker first ascertained by the study of their evolution in
the guinea-pig;* subsequently, he extended his observations, and
found that the spermatozoa in man were evolved in a manner pre-
cisely similar.
Valentinf during his inquiries observed masses of filaments in the
mother cells of the rabbit and bear, and Hall man J noticed the same
thing in those of the rays ; he does not, however, speak of the trans-
formation of the included nuclei or ova.
In the class of invertebrate animals, it is most probable that a sim-
ilar method of development prevails.
The spermatozoa are not encountered in equal numbers in all parts
of the testicle, the more remote convolutions of the tubuli seminiferi
containing chiefly the simple granular cells and the spermatophori,
while it is only in those which approach near to the epididymis that
they occur in any numbers; in this situation they usually lie immedi-
ately beneath the membrane of the seminiferous tube, and external to
the spermatophori, their long axes being disposed in the direction of
that of the tube itself. In the vas deferens the spermatozoa are pres-
* Beitrag. p. 56. tab. 11. fig. 20. f Repert. p. 145. 1837.
\ Muller, Archiv. p. 471. 1840.
232 ORGANIZED FLUIDS.
ent in vast numbers, and with scarcely any admixture of the other
solid elements of the testes.
It is in the epididymis that the different stages of development of
the seminal animalcules are best seen side by side.
The spring is by far the most suitable period for the study of the
development of the spermatozoa, and birds, especially those of the order
Passeres, present the best examples in which to trace their evolution,
because in them the seminal animalcules are large, and the reproduc-
tive function is excessively active for a brief and determined period.
Wagner* has shown that from the commencement of the time of
moulting, and through the entire winter, the testes of birds undergo
an extraordinary degeneration, the spermatozoa and the spermato-
phori being entirely obliterated, and the volume of the testes reduced
to at least the twentieth or thirtieth of the size to which they attain
in spring. Thus, the testis of the common chaffinch is in winter not
larger than a millet-seed, while in spring it exceeds a pea in size.
The same degeneration is doubtless experienced during winter,
although to a less extent, by most animals of the class Mammalia.
THE SPERMATOZOA ESSENTIAL TO FERTILITY.
The spermatozoa do not exist in the testes of mammalia at all
periods of life : thus, they do not make their appearance in that organ
in man until the period of puberty, and they disappear gradually as
old age advances. It is impossible, however, to determine the time
at which they are first developed, or at which they cease to exist in
that organ, because the period of puberty differs in different individ-
uals, and some men are aged in constitution when others of the
same years are hale and robust. Certain it is, that some men retain
the power of engendering until a very advanced age, of which fact
the celebrated Parr presents a memorable example, he having become
a father at the extraordinary age of 142.
The number also of the spermatozoa contained in the seminal fluid
varies in different individuals, and is usually in proportion to the
activity of the reproductive function, and this again is dependent to
a great extent upon the constitutional powers as well as upon the
mode of life.
The activity, then, of the reproductive faculty in man is in many
cases a good test of health.
The above few facts favour the idea of the essentiality of the
* Elements, pp. 28 and 29.
THE SEMEN. 233
spermatozoa; others, however, of a stronger kind, still remain to be
mentioned.
Wagner has instituted some most interesting inquiries in reference
to the condition of the spermatozoa in male hybrids, and especially in
ma^e hybrid birds, and he finds, that in them the characteristic ani-
malcules are either altogether wanting, or occur but in small numbers,
and are ill-formed and ill-conditioned; the hybrids in which the sem-
inal animalcules have been thus found to be absent or degenerated,
have been ascertained to be incapable of having offspring.*
Again, Leeuwenhoekf discovered living seminal animalcules in the
uterus and Fallopian tubes of bitches seven days after connexion. J
Prevost and Dumas§ have more recently made the same observa-
tions at the same length of time after intercourse.
Siebold|| has detected the spermatozoa in a living state in the uterus
and Fallopian tubes eight days after connexion. snj
Lastly, BischoffTl and Martin Barry** have observed the sperma-
tozoa not merely in the uterus and Fallopian tubes, but also on the
ovary itself.
From these facts it is therefore evident that the spermatozoa are
essential to fecundity, although the precise manner in which they
are so is still involved in the greatest obscurity. It is supposed by
some observers, that they make their way into the ovum itself: this
notion is as yet without evidence to support it.
It would be most interesting to determine whether impregnation
could be procured by the artificial introduction of semen, the animal-
cules of which were dead; there is every reason to believe that in the
many cases in which the artificial injection of the seminal fluid has
* Loc. cit. pp. 30 — 34. f Opera Omnia, p. 150.
\ Leeuwenhoek signalized the discovery of the living spermatozoa in the uterus
and Fallopian tubes, in the following words : " Nudo conspiciens oculo, nullum mas-
culum semen canis in ea esse dicere debuissem; at eandem mediante bono micro-
scopio, summse mese voluptati immensam viventium animalculorum multitudinem;
semen nempe canis masculum contemplabar. His peractis, dictam aperiebam tubam,
in fine suae crassitudinis, ac ibidem quoque magnam seminis masculi canis contem-
plabar copiam, quod semen illic vivebat, et hoc modo quoque cum dextra egi tuba,
ac in eadem quoque immensam seminis viventis canis masculi copiam observavi. . .
Materiam qua matrix concita est, observans, majorem adhuc viventium animalculorum
copiam deprehendebam."
\ Annales des Scien. Nat. t. iii. p. 122.
|| Miiller, Archiv. p. 16. 1841. IT Wagner's Elements, p. 66.
** Researches in Embryology, Second Series, Phil. Trans, p. 315. 1839.
234 ORGANIZED FLUIDS.
been successful, the contained spermatozoa were in a living condition;
and from all that is yet known in relation to the animalcules, there is
strong presumption to believe that the experiment referred to, viz:
the introduction of semen, the animalcules of which were dead, would
be unattended with success.
One remarkable experiment of Spallanzani, however, deserves to be
referred to. Most observers agree in saying, that the spermatozoa of
the frog die after some hours of immersion in water. It is known,
however, that Spallanzani succeeded in fertilizing the ova of frogs
with spermatized water, containing three grainsof seminal fluid to
eighteen ounces of water, thirty-five hours after the mixture had been
prepared, and this, in a chamber with the thermometer at from seven-
teen to nineteen degrees; and again, that in an ice-house, the ther-
mometer being three degrees above zero, the spermatized water
preserved its prolific power for fifty-seven hours.
Now, the tendency of this interesting experiment is certainly to
prove the possibility of fertilization occurring with semen, the sper-
matozoa of which are dead: this inference would appear, however, to
be negatived by another ingenious experiment of MM. Prevost and
Dumas, who filtered the seminal fluid, and found that the fluid portion
which passed through the filter would not vivify the eggs, while the
more solid part, consisting of the spermatozoa, produced the results
peculiar to the seminal fluid.
Jacobi succeeded in fertilizing the ova of a carp with semen which
had been contained within the body of the fish for four days; but it
is well ascertained that the spermatozoa of fishes in general live for a
much longer period than that named.* Some have supposed that
the only use of the spermatozoa is by their movements to hasten the
advance of the semen towards the Fallopian tubes.
PATHOLOGY OF THE SEMINAL FLUID.
The quantity of seminal fluid secreted varies greatly according to
the age and constitution of the individual. In young men, and in
those whose health is vigorous, the secretion is rapid and abundant;
in the aged, and in those whose vital powers are feeble, it is but slow
and scanty. It is, however, in severe states of disease that the amount
of seminal fluid secreted is greatly diminished, if the formation of it
be not in some cases altogether suspended for a time. Under the
* Several most interesting particulars in reference to artificial impregnation are
given in Wagner's Elements, chap. iii.
THE SEMEN. 235
influence of recovery, the quantity of semen formed again undergoes
an augmentation.
An inordinate secretion of the seminal fluid, as also its prolonged
retention in the testes, are sometimes the causes of involuntary sem-
inal discharges, which, however, are far more frequently occasioned
by organic weakness, the result of over-indulgence.
If these emissions be very frequent, the ejaculated semen will be
found to be thin and watery, and to contain comparatively few
spermatozoa.
It is unnecessary to describe here the destructive effects of these
emissions on the constitution.
It is often a matter of great importance to determine, independently
of any revelation on the part of the patient, whether in any particular
case seminal effusions exist.
This fact, it is in the power of the microscope, according to some
observers, in all cases to declare with the most absolute certainty.
After each effusion of semen, in whatever way occasioned, a cer-
tain amount of that fluid will still remain behind, adhering to the
surfaces of the urethra; this, of course, contains the seminal animal-
cules, which will be washed away on the first passage of the urine
through the urethra.
The great object, then, is to establish the fact of the existence of
spermatozoa in the urine : this may be accomplished in two ways ;
either by filtration or decantation, the latter being perhaps the pref-
erable method of the two; the spermatozoa, being heavier than the
urine itself, always subside at the bottom of the vessel, and where
they may always be found, if present in even the smallest numbers.
The urine, as already mentioned, has the property of preserving
the seminal animalcules, which may be detected in it months after
their discharge from the urethra.
M. Donne* states, that he has never succeeded in detecting the
seminal animalcules in the urine, unless as the consequence of an
emission of semen, and which may have occurred either during con-
nexion, in an involuntary manner, or through masturbation. Now,
if this be true, the occurrence of the spermatozoa in the urine declares
positively the fact, that a discharge of semen has been sustained, and
this particular is often in itself sufficient to enable a medical man to
form an opinion of the case.
It seems to me, however, by no means sufficiently proved, that an
* Cours de Microscopie, p. 318.
236 ORGANIZED FLUIDS.
escape of the seminal fluid with the urine does not take place inde-
pendently of any distinct emission. I am inclined to think that such
escape is an habitual occurrence even with the most healthy, especially
with the continent, and that by it the surcharged testes are relieved
whenever requiring such relief.
This view is to some extent supported by the observations of Dr.
John Davy* and Wagner :f the former excellent observer states
that on examining the fluid from the urethra after stool in a healthy
man, he had always detected spermatozoa.
In connexion with the above few remarks on the pathology of the
semen, we may refer to the observations of Donne" on the effects of
an exceedingly acid condition of the mucus of the vagina, and a
very alkaline state of that of the uterus itself, on the vitality of the
spermatozoa.
The mucus of the vagina, in its normal state, is slightly acid, this
degree of acidity being perfectly compatible with the life of the sem
inal animalcules; but Donn6 has shown that under some circum-
stances— as from congestion, irritation, or inflammation — this mucus
becomes so strongly acid as to destroy in a few seconds the vitality
of the spermatozoa.
Again, the mucus of the uterus in its healthy state is slightly alka-
line, but not so much so as to exert any injurious effects upon the
spermatozoa; in conditions of derangement and disease, however, it
becomes so alkaline, as Donne" has shown,J that in like manner with
the acid mucus of the vagina, it kills the seminal animalcules in a
very short space of time.
Now, after what has been said and detailed in reference to the
essentiality of the spermatozoa, it can scarcely be doubted that
women whose vaginal and uterine secretions are so disordered, are
inapt to conceive, and this from the effect of their vitiated secretions
upon the spermatozoa.
It would be interesting to determine whether the spermatozoa are
ever entirely absent from the semen of man: it is very probable that
in certain rare cases they are so, and from the facts already ascer-
tained there can be no doubt that those individuals whose spermatic
fluid is devoid of its characteristic living element, would be wholly
incapable of having offspring.
It is probable that in the impotent the spermatozoa are almost, if
not entirely, extinct.
* Edin. Med. Surg. Jour. vol. ii. p. 50. t Loc. cit. p. 21.
t Cours de Microscopie, p. 292.
THE SEMEN. 237
APPLICATIONS OF A MICROSCOPIC EXAMINATION OF THE SEMEN TO LEGAL MEDICINE.
The detection of the spermatic animalcules is frequently a matter
of high interest and importance in a medico-legal point of view.
There are three classes of cases in which the microscope, by
revealing the presence of spermatozoa, is capable of forwarding the
ends of justice, and of bringing conviction home to the guilty.
1st. In cases of suspected violation.
2d. In determining the nature of doubtful stains observed on the
bed-clothes, &c.
3d. In unnatural offences.
With respect to those cases which come under the first division, it
may be observed that the medical testimony on which these are
usually decided is too often of such a nature as to lead to the acquittal
of a really guilty individual ; the medical man, judging merely from
external appearances, being compelled to give evidence either directly
favourable to the prisoner, or which is at best but of a doubtful
character.
In suspected violation, then, when the evidence to be deduced from
an outward examination is insufficient for the formation of a satis-
factory and decided opinion, the microscope may frequently be
employed with the greatest advantage.
If the offence imputed has been committed, and if connexion has
really occurred, then by means of this instrument, provided too long
a time has not elapsed from the period of the occurrence, that is to
say, a period not exceeding from twenty-four to forty-eight hours, the
spermatozoa will be detected in the mucus, properly examined, and
obtained from the upper part of the vagina: now, the detection of these
in such a situation is a demonstration that intercourse has taken place.*
The examination of the urine of women whose persons are sus-
pected to have been violated would also frequently furnish evidence
of the fact by manifesting the presence in it of the spermatozoa, which
in its passage through the vagina it had washed away from its walls.
With reference to the second class of cases mentioned, those
requiring for their satisfactory elucidation the determination of the
nature of suspicious stains, here again, by means of the microscope,
evidence the most conclusive may frequently be obtained.
* Donne, in the Cours de Microscopie, states that he has detected the spermato-
zoa in the vaginal mucus of women admitted into the hospital, in which instances it is
most prohable that connexion had occurred at least some hours previous to admission.
238 ORGANIZED FLUIDS.
Now, if the stains in question be formed by the seminal fluid, and
if they be not too old, the microscope applied to them will detect in
them the spermatozoa.
With regard to the length of time at which the spermatozoa may
be detected in the matter of a stain, I have reason to think that this
has scarcely a limit: I have myself noticed them in the semen several
weeks old, and they then appeared to have undergone scarcely a
single appreciable change, the spermatophori contained in the seminal
fluid being equally well seen.
In examining stains occasioned by the seminal fluid, it is advisable
to use the same precautions as those which were pointed out in
reference to blood stains, and to moisten them with either serum or
albumen.
The reader's imagination will suggest to him numberless cases in
which the determination of the nature of suspected stains would be
a matter of the utmost importance, and would lead to the production
of evidence of the greatest consequence, and in no other way
obtainable.
Lastly, with reference to the third class of cases, those of unnatural
offences: here also the microscope, by revealing the presence of the
spermatozoa in the rectum, or on some other part of the body, may
throw great light on occurrences which otherwise would in all proba-
bility be buried in complete oblivion and mystery.
An examination of this kind was assigned by the magistrates in
France some years ago to two physicians, on the occasion of an
assassination in a hotel. A traveller having been killed by a young
man whom he had received into his chamber during the night, justice
was interested to know whether semen would be found in the rectum
or not.*
It is known that in death by hanging, an emission of the semen
usually occurs, and this, in the absence of other proofs, has been
adduced as a sign of death by suspension. It would appear, however
that such an indication is not without its sources of fallacy.
It is thus apparent that in the cases here referred to, the microscope
is capable of affording positive evidence of a most important and
conclusive kind; on the other hand, the negative testimony deduci-
ble from its application in these cases is not without its value.
* See Annates d'Hygiene Publique el de Medecine Legale, Paris, 1839, t. xxi. pp.
168 and 466.
THE SEMEN. 239
SEMEN.
[In making examinations of the seminal fluid, the purest and most con-
centrated will be found in the vas deferens or epididymis The sooner this
is examined after the death of an animal, the less change will be detected,
and the motions of the spermatozoa will be most active. If a small drop of
the fluid is placed on a plain glass slide, covered with thin glass, and placed
in the field of the microscope, many of the spermatozoa will be seen in active
motion, with a ith-inch object-glass. It will be found better to dilute the
fluid before covering it with the thin glass. For this purpose, albumen, or
a little water which has -^\th part of salt or sugar dissolved in it, will answer,
or, still better, a little serum of the blood. When properly diluted, the
thin glass is applied, as before, and the seminal animalcules will be much
better defined than without this dilution. The reagents most striking in their
effects have already been pointed out.
PRESERVATION.
The seminal animalcules may be preserved, either in their own fluid, or
in a weak solution of salt and water, or of chromic acid. In either case,
the flat cell, or the thin glass cell, is to be employed, and the cover cemented
with gold-size. In this condition, they will keep for many years.]
UNORGANIZED FLUIDS.
ART. VII. — SALIVA, BILE, SWEAT, URINE.
The fluids comprised under the heading of Unorganized Fluids
differ from those of the first division, viz: the Organized, in that
they do not contain, as essential elements, organized structures; solid
organic particles are indeed usually to be encountered in them, but
these are to be regarded either as accidental, or at all events as non-
essential adjuncts, and which appertain usually to the structure of
those organs from which the fluids have themselves proceeded.
The presence and nature of the solids contained in the Unorgan-
ized Fluids serve to indicate, to a considerable extent, the condition
of the glands by which they have been secreted, and thus frequently
throw great light upon their pathology.
There is, however, one kind of solid constituent which is found
almost constantly in these fluids, viz: the crystals of various salts:
these being, however, unorganized, their consideration does not prop-
erly belong to a work devoted to descriptions and delineations of
organized tissues.
It is proposed, therefore, in order to render the application of the
microscope to human physiology and pathology as complete as possi-
ble, to prepare a separate treatise on the subject of the crystallizations
formed in the various fluids, &c, of the body, under the title of
Human Crystallography.
We will now pass in review the fluids comprehended in the division
of Unorganized Fluids. In reference to some of them, but little
remains to be said, as will have been inferred from a knowledge of
their structureless character. In the treatise on Crystallography,
however, many interesting and important details will be given.
The Unorganized Fluids comprise the saliva, the bile, the sweat,
the urine, and the gastric, pancreatic, and lachrymal fluids; these
THE SALIVA,
211
several fluids especially deserve the name of secretions, since they
are elaborated by large and complexly organized glands.
THE SALIVA.
The saliva is a peculiar fluid secreted by the parotid, sub-maxillary
and sub-lingual glands, from which it is conveyed by certain ducts
into the mouth, where it becomes mingled with the buccal mucus.
The amount of saliva secreted during the day is estimated at from ten
to twelve ounces; during salivation, either spontaneous or induced
by mercury, the quantity may exceed two or three quarts. It is
worthy of remark, however, that in these latter cases the mercury has
never been detected in the saliva.
Mitscherlich* made the following observations on a person having
a salivary fistula, and in whom the saliva could be collected directly
as it flowed from Steno's duct. He found that there was no flow of
saliva while the muscles of mastication and of the tongue were in
complete repose, and all nervous excitement avoided. He observed,
also, that during the acts of eating and drinking, especially at the
commencement, the secretion was most abundant, and in proportion
to the stimulating nature of the food and the degree to which it was
masticated. From two to three ounces of saliva flowed from the
duct in the course of twenty- four hours.
The solid constituents of the saliva are composed of fat, ptyalin,
watery and spirituous extractive matters, a little albumen, certain
salts, a trace of sulphocyanogen, mucous corpuscles, epithelial scales,
and, lastly, corpuscles resembling mucous globules, which have been
termed salivary corpuscles, and which are probably nothing more
than epithelial cells in progress of development.
The salts of human saliva are, according to Mitscherlich, chloride
of calcium, lactates of soda and potash, soda, either free or combined
with mucus, phosphate of lime, and silica.
In certain pathological states Simon detected in the saliva acetic
acid, and a considerable quantity of a substance resembling caseine.
The saliva is with difficulty to be obtained in a pure state, it being
generally intermixed with a greater or less quantity of buccal mucus ;
now the normal reaction of the saliva is alkaline, that of mucus acid;
it therefore follows, the fluids in question being thus intermingled in
variable proportions, that the reaction presented by the fluid obtained
varies according to the relative quantity of each ingredient; thus.
* Rust's Magaz. vol. xl.
16
242 UNORGANIZED FLUIDS.
sometimes the saliva, when tested, will appear to be acid, alkaline, or
neuter, and the same will be the case with the buccal mucus.
The true reaction of the saliva, then, can be ascertained only by
obtaining it unmixed with the mucus of the mouth, and then testing
it; this may be effected by first washing the mouth with water, and
then applying the test-paper to the saliva as it flows from the orifice
of its ducts.
The fact referred to of the admixture of the two fluids, saliva and
mucus, will serve to explain why test-paper, applied to the upper
surface of the tongue, exhibits frequently an acid reaction, while that
placed beneath it manifests the presence of an alkaline fluid.
In morbid states the normal reaction of the saliva may undergo a
complete change, and it may become either neuter or acid : this
alteration has been especially observed to occur in deranged condi-
tions of the stomach, in acute rheumatism, in cases of salivation, and,
according to Donne\ in pleuritis, encephalitis, intermittent fevers,
uterine affections, and amenorrhea.
Acid saliva doubtless exerts a very injurious effect upon the teeth.
The admixture of the saliva with mucus is readily shown by means
of the microscope, which reveals the presence of mucous epithelial
scales in all stages of their development; as the scales found in the
sweat are derived from the desquamation of the epidermis, so are
those of the saliva and mucus from that of the epithelium.
The saliva, as well as the sweat, yields on evaporation crystals of
the various salts referred to in the analysis.
Blood corpuscles are sometimes present in the saliva and mucus;
these proceed usually from the gums.
The uses of the saliva in the animal economy are classified by Dr.
Wright as follow:
Active. — 1. To stimulate the stomach and excite it to activity by
contact. 2. To aid the digestion of food by a specific action upon
the food itself. 3. To neutralize any undue acidity of the stomach
by supplying a proportionate alkali.
Passive. — 1. To assist the sense of taste. 2. To favour the
expression of the voice. 3. To clear the mucous membrane of the
mouth, and to moderate thirst.
The bile, like the unorganized fluid already described, presents but
little of interest to the microscopist in its normal state.
THE SWEAT. 243
It happens, however, occasionally, when it has been retained in the
gall-bladder for a long time, in consequence of which it has become
inspissated, that it does contain solid and coloured particles.
These particles have been noticed by Scherer* and also by Dr. H.
Letheby of the London Hospital, who was so considerate as to trans-
mit, for my examination, a portion of inspissated bile, containing
them, as also plates of cholesterine, in great numbers.
The bodies in question consist of two parts, an external colourless
investing portion, and an internal coloured and granular matter; this
disposition of the colouring matter imparts to them the aspect of
" pigment cells," which, in fact, Scherer considers them to be.
There are but three kinds of cells, which, if cells at all, they could
be by any possibility, viz: liver, epithelial, or pigment cells. Now,
they are certainly neither of the first two mentioned, as may be
inferred from the dissimilarity of size, appearance, and structure with
these; and they are as surely not "pigment cells," because such
structures do not enter into the organization of the liver.
It is, then, conceived that these cell-like bodies are not true cells,
but are to be regarded as masses of concrete mucus, enclosing more
or less biliary colouring matter; the great differences observed in
their form, size, and general appearance, are all opposed to the notion
of their being definitely organized cells.
The meconium of infants very generally contains the cell-like
bodies described, together with intestinal mucus, cuneiform epithelium,
and occasionlly cholesterine in a crystalline form.
THE SWEAT.
The sudoriparous glands, distributed over the whole surface of the
body, constantly secrete a very considerable quantity of watery
fluid: this fluid passes off usually in the form of an insensible vapour;
in some cases, however, as under high external temperature, active
exercise, and in certain stages and forms of disease, it collects on the
skin in the form of drops, which, in drying up, deposit their solid
constituents over the whole extent of the cutaneous surface : it is
then more particularly termed sweat.
Many attempts have been made to determine the amount of fluid
passing off by the skin; the average quantity, according to Seguin
amounts to about twenty-nine ounces of fluid, the maximum to five
* Unlersuchungen, &c, p. 103.
244 UNORGANIZED FLUIDS.
pounds, and the minimum to one pound, eleven ounces, and four
drachms.
The amount of solid constituents carried off with the fluid is,
comparatively, very small, not exceeding in the twenty-four hours
seven or eight scruples ; the remainder being merely water, retaining
in it -carbonic acid and nitrogen, the quantity of the former gas being
increased by vegetable diet, and the amount of the latter by an
animal regimen.
Simon has established the existence, in normal sweat, of —
1. Substances soluble in ether: traces of fat, sometimes including
butyric acid.
2. Substances soluble in alcohol: alcohol extract, free lactic or
acetic acid, chloride of sodium, lactates, and acetates of potash and
soda, lactate or hydrochlorate of ammonia.
3. Substances soluble in water : water extract, phosphate of lime,
and occasionally an alkaline sulphate.
4. Substances insoluble in water: desquamated epithelium, and,
after the removal of the free lactic acid by alcohol, phosphate of lime
with a little peroxide of iron.
The quantity of fluid exhaled is subject to very great variations;
thus, it is increased by a dry and light atmosphere, while it is dimin-
ished by a damp and dense condition of the air. It is at its minimum
at and immediately after meals, while it is at its maximum during the
actual period of digestion. The cutaneous perspiration is in antago-
nism with the urinary secretion; thus, an excessive secretion of
urine diminishes that of the skin, and a diminution of the activity of
the kidneys is usually followed by an augmentation of that of the
sudoriparous glands.
But little of interest, in a microscopic point of view, attaches to
this fluid; the only solid organic constituent contained in it being
detached scales of epidermis, which is ever undergoing a process of
destruction and renewal; these scales, therefore, do not form part of
the sweat, but become mixed up with it in a secondary manner.
The copious formation and discharge of the cutaneous fluid which
occur under certain circumstances, thus do not merely afford a relief
to internal organs, but serve, also, by detaching and washing away
the older and useless cells, to cleanse the epidermis, and to render this
more efficient as an evaporating surface.
The crystals formed on the evaporation of the sweat, in states of
THE URINE. 215
health and disease, have been but little studied; it is probable that a
knowledge of them would lead to the discovery of some facts of interest.
The cutaneous fluid, it is known, is in health acid ; there are some
situations, however, in which it is constantly alkaline, as in the axilke,
about the genital organs, and between the toes ; this, probably, arises
from its admixture with the secretions of the small follicles which
are situated in those parts.
The sweat, like the urine, is to be regarded as a cleansing fluid,
the system being through it relieved of certain surplus and effete
matters.
The pathology of the sweat is but little known ; albumen has been
observed in it by Anselmino, in a case of febris rheumatica, and
Stark states, that it may be met with in the sweat in gastric, putrid,
and hectic diseases, and also on the approach of death. The amount
of acetic acid, ammonia, and the salts, may all be increased. Uric
acid and quinine have been found in the sweat, the latter preparation
being of course at the time administered medicinally.
THE URINE.
Few fluids have been more studied of late years by the micro-
scopist than the urine; this has arisen from the elegance of form,
variety of composition, and important character of the numerous
crystalline deposits which are formed in it in states of health and
disease, and which can be satisfactorily determined only by the aid
of the microscope.
The great advantage of the application of the microscope over
that of chemical tests to the study of the urine is, that the indications
which it affords are not merely certain, but also prompt and facile,
while the results obtained through the agency of chemistry, although
not less certain, are often tedious and difficult.
The description of the various crystals formed in the urine is
reserved for another occasion ; in this place will be noticed only the
organic constituents which occur in normal and abnormal urine.
In order that the pathological alterations to which the urine is
liable may be more clearly understood, it will be advisable, first, to
describe the appearance and the constitution of healthy urine.
Healthy urine, when first passed, is a limpid fluid of an amber
colour, emitting a peculiar odour, exhibiting an acid reaction, and
having a specific gravity of about 1011.
Abandoned to itself, it soon loses its limpidity, becomes troubled,
246
UNORGANIZED FLUIDS
and putrefies more or less quickly, according to its chemical consti-
tution and the state of the temperature.
The following is Berzelius' analysis of healthy urine, and with
which all other subsequent analyses have been found to agree to a
very considerable extent: 1000 parts contained —
Water,
-
933 00
Solid residue,
-
67 00
Urea,
-
30-10
Uric acid,
-
100
Free lactic acid, lactate of
ammonia
alcohol
and water extract,
-
1714
Mucus,
-
0 32
Sulphate of potash,
-
371^
Sulphate of soda,
-
316
Phosphate of soda,
-
2 94
Biphosphate of ammonia,
-
165
Chloride of sodium,
-
4-45'
Chloride of ammonium,
-
150
Phosphate of lime and mag]
lesia,
100
Silicic acid,
-
0 03>
Fixed
L salts,
15 29.
It will be seen from the above analysis that healthy urine does not
contain the nitrogenized principles albumen, fibrin, or caseine, which
are encountered so frequently in urine voided in disease.
The only solid organized constituents which are constantly encoun-
tered in healthy urine, are mucous corpuscles and epithelial scales;
these do not form part of the urine, but belong to the structure of
the mucous membrane of the bladder and urethra, and both of them
may be detected with the greatest facility by the microscope. On
account of their greater specific gravity, they subside at the bottom
of the vessel containing the urine, where they may, at most times, be
procured for examination.
Occasionally, however, in the urine of man, under the circum-
stance already referred to in the article on the semen, the sperma-
tozoa are present in the urine also.
PATHOLOGY OF THE URINE.
The organic principles contained in diseased urine may be divided,
firstly, into those which are usually encountered in that fluid in a
THE URINE. 247
state of solution, but which do yet, under certain circumstances,
assume the solid form ; and, secondly, into those which, being definite
organisms, occur only in a solid condition. Albumen, fibrin, caseine,
and fat, belong to the first, and the blood and pus corpuscles to the
second division.
Albuminous Urine.
Albumen is frequently present in the urine in disease; it has been
noticed to occur especially in Bright's disease of the kidney, and in
the urine passed after scarlatina.
If the albumen be present in any considerable quantity, nitric acid
or bichloride of mercury will cause a precipitate, and the urine will
become turbid on the application of heat, and deposit flocculi of
coagulated albumen.
The colour, specific gravity, and reaction of albuminous urine are
various ; thus, it may be either light or dark coloured, it may be of
high or low specific gravity, it may exhibit either an acid or an
alkaline reaction, or it may be neutral.
When the albumen is small in quantity, heat is the most efficient
test for its detection; it is only when the urine manifests a decided
alkaline reaction, that nitric acid is preferable, the albumen being
held in solution by the free alkalies.
Urine may, however, become turbid from the application of heat,
even when no albumen is present ; this arises from precipitation of
the earthy carbonates; in these instances, the addition of nitric acid
will immediately disperse the cloudiness, and the reapplication of heat
will not occasion any further precipitation.
Dr. G. O. Rees has observed that the urine of persons who have
been taking cubebs or balsam of copaiba is rendered turbid by nitric
acid, although it contains no albumen; this urine, however, is not
affected by heat.
From the facts contained in the two preceding paragraphs, it
follows that a precipitate might possibly ensue on the application
of heat, and by the addition of nitric acid, and yet no albumen be
present in the urine.
If the precipitate yielded by nitric acid, added to urine impregnated
with the active principles of cubebs or copaiba, be examined with the
microscope, it will be found to consist of minute oil bubbles, which
are of course readily soluble in ether.
248 UNORGANIZED FLUIDS,
Fibrinous Urine.
Fibrin has been encountered in the urine independently of the
other constituents of the blood : Zimmerman* has described seven
cases of fibrinous urine.
Such urine, if the fibrin existed in it in any quantity, would
coagulate or form a clot.
It is necessary in these cases not to confound mucus with fibrin ;
the former, under the microscope, exhibits the well-known mucous
corpuscles, while the latter appears either filamentous or simply
granular.
Fatty Urine.
The urine may contain fat, either separately or conjointly with
albumen, or with caseine, and probably also sugar: the urine holding
fat in a free state may be called fatty ; that in combination with
albumen, chylous ; and lastly, the urine in which fat occurs in con-
nexion with caseine and sugar may be denominated milky urine.
Fatty urine has been observed to occur frequently in persons labour-
ing under phthisis; the fat, as the liquid cools, forming a thin pellicle
on its surface, the nature of which may be at once ascertained by the
microscope, which, if it be really fatty, will reveal the presence of
innumerable fat globules.
Cases have been recorded in which the quantity of fat has been so
considerable that it could be detected with the naked eye.
Chylous Urine.
Chylous urine is a white semi-opaque fluid, and contains both fat
and albumen; the former may be detected by means of the micro-
scope, and the latter will be coagulated by heat, by nitric acid, and
the bichloride of mercury. Examined microscopically, the coagu-
lated albumen exhibits a granular texture.
This form of urine has been observed principally in cases of gout.
Milky Urine.
True milky urine is of very rare occurrence, there being but two
or three well-authenticated cases of it recorded; urine containing the
constituents of chyle having doubtless been described, in many
instances as milky urine.
* Zur Analysis und Sunthesis der pseudoplastischen Prozesse, Berlin, 1844, p. 129.
THE URINE. 249
The fat in milky urine occurs in combination with caseine, and
probably with sugar also.
The fatty constituent may be detected as in the previously-decribed
urines, the fatty and the chylous, by means of the microscope, and the
caserne will be precipitated by the addition of a little acetic, dilute
sulphuric, or hydrochloric acid, the flocculi of which, examined micro-
scopically, will exhibit a granular, and even in many cases a globular con-
stitution ; they will contain also a greater or less number of fat globules.
Urine containing caseine in solution may be distinguished from
albuminous urine by the application of heat, which in the latter will
occasion a precipitate, none being formed in the former, unless, indeed,
a considerable quantity of nitric acid be also present in the urine,
when a temperature of 104° Fah. will be sufficient to occasion the
precipitation of the caseine.
It is not to be supposed, by the use of the term milky urine, that
the milk, as such, ever exists in the urine, and that it finds its way
there from the mammary gland by metastasis; the utmost that is to
be inferred, from the existence of the principal elements of milk in the
urine, is, that the kidney, in place of the mammary gland, has sepa-
rated those elements from the blood.
Excess of Mucus in the Urine.
In catarrhus vesica, an affection to which old persons are particu-
larly liable, mucus is secreted in considerable quantities, and is voided
with the urine.
This mucus subsides to the bottom of the vessel, is semi-opaque,
thick, and ropy; examined with the microscope, mucous corpuscles
and epithelial scales are encountered in it.
In those cases in which the urine is very alkaline, the mucus is
observed to be particularly tenacious and thready; this condition
results from the action of the free alkalies contained in the urine upon
the constitution of the mucus.
Blood in the Urine.
Blood is frequently contained in the urine, and voided with it; thus,
it is frequently encountered, in greater or less quantity, in the follow-
ing cases : in inflammation of the kidneys, in injui'ies of those organs,
or of the bladder itself, in cases of stricture from the introduction of a
catheter, from the passage of renal or urinary calculi, and, lastly, from
chronic disease of the kidneys and bladder.
250 UNORGANIZED FLUIDS.
The best test of the existence of the blood in the urine is the
detection of the blood corpuscles by the microscope ; blood, however,
may exist in the urine, and yet no corpuscles be detected, these having
been dissolved by the acids of the urine. Failing, however, to detect
the blood discs, if blood really be present, then the albumen, fibrin,
and hematin will still remain, and may be distinguished by suitable
reagents.
From the colour of urine, no conclusion can be formed as to the
existence of blood in it, as urine of a deep blood-colour is some-
times met with, which on examination is found not4o contain any
trace of blood.
Pus in the Urine.
It has already been stated in these pages that no absolute distinction
exists between mucus and pus; and, therefore, it follows that it is in
most cases impossible to determine, with any degree of certainty,
whether pus exists in the urine or not.
If, however, the sediment rendered with the urine want the tenacity
of vesical mucus, and contain the granular corpuscles common to
mucus and pus, there is reason to suspect that the fluid in question is
really purulent.
The diagnosis will, however, be greatly assisted by reference to the
history and symptoms of the case ; thus, if there be rigors and hectic
fever, the probability of the existence of pus will be much strengthened.
There is one circumstance which requires to be mentioned, and
which greatly increases the difficulty of discrimination between mucus
and pus. In some cases of purulent urinary deposits, the urine is
alkaline; now, the effect of the action of alkalies on pus is to convert
it into a transparent and tenacious substance in every respect resem-
bling mucus, and which, therefore, cannot be distinguished from it.
There are but few details interesting to the microscopist connected
with the Gastric, the Pancreatic, and the Lachrymal fluids; it will,
therefore, be unnecessary to treat of them at any length. It is to the
chemist and physiologist chiefly that the gastric fluid is interesting.
They all, however, but especially the gastric and the lachrymal secre-
tions, contain mucous corpuscles and epithelial scales, derived from
the desquamation of the epithelium of the surfaces by which they are
secreted, and over which they pass.
THE URINE. 251
Obs. — At page 135, the opinion is attributed to Mr. Addison, that
the white corpuscles of blood, mucus, and pus contain filaments;
whereas it would appear, from a closer examination of the text, that
the statement of that gentleman only goes to the extent of asserting,
that' the fluid enclosed in those corpuscles resolves itself in its escape
into the filaments, of which the fibrinous portions of blood, mucus, and
pus are under certain circumstances observed to be constituted.
252 UNORGANIZED FLUIDS.
URINE.
[In the pathology of the urine, the microscope has now become of equal
value with chemistry ; a proper consideration of this whole subject would
require a volume of the size of the present one, and therefore it is not here
attempted. For reference on this subject, especially on the microscopical
characters of urine, the student may consult "Simon's Chemistry of Man,"
" Bird on Urinary Deposits ;" " Practical Manual on the Blood," by John Wm.
Griffith; "On the Analysis of the Blood and Urine," by G. Owen Rees;
"A Guide to the Examination of Urine," by Alfred Markwick; "Frick on
Renal Diseases;" "Prout on do."
Those who wish to study the pathology of the urine, with the microscope,
will find the following hints useful. After allowing the urine to stand for a
little time, more or less sediment will take place. This is to be drawn up
by means of a pipette, and a drop placed on a plain glass slide, and covered
with thin glass. It is then ready for examination, first with a one-fourth
inch object-glass, and afterward with a one-eighth. This high power is
necessary to recognise the presence of blood, mucus, or pus corpuscles, or
the minute crystals of oxalate of lime.
When the presence of an undue quantity of lithate of ammonia is sus-
pected, the test-tube or other glass vessel containing the urine must be
heated gently, when the supernatant fluid, with the lithate, may be poured
off", or removed with a pipette. Most of the urinary sediments can be well
preserved ; the most transparent, such as oxalate of lime, &c, are best
mounted in fluid. For this they are prepared by being repeatedly washed
in distilled water, until all trace of gummy matter, so often combined with
urinary deposits, is removed. They are then placed on a plain glass slide,
or in a thin glass cell, mixed with a little water by means of a pipette, and
the water allowed to evaporate. A drop or two of alcohol and water, of
Goadby's solution, or of the creosote-water, is to be added, and the thin glass
cover applied and cemented with gold size, care being taken that no air-
bubbles are present.
Other urinary deposits, requiring to be rendered more transparent, are
best preserved in Canada balsam. The deposit must be well washed as
before, and after being placed on the glass slide, and the water allowed to
evaporate, must be mounted in balsam with heat, as directed in the chapter
on the Preservation of Objects. Certain deposits are best preserved in the
dry way, such as uric acid, &c.
Other sediments, and these are chiefly salts, are best mounted in syrup,
made thick, and mixed with a little gum. This is to be used in the same
way as the balsam without heat, and the sediment deposited in the thin
glass cell, or that made with asphaltum or other cement. Castor oil has
been successfully used as a medium for mounting urinary deposits. In this
method, no heat is necessary.]
PART II. — THE SOLIDS.
The division of the various constituents of the animal fabric into
the two orders of Fluids and Solids, although a very ancient one,
is yet, to a certain extent, arbitrary and artificial. The truth of this
observation is rendered apparent on reference to the several fluids,
the description of which has just been brought to a conclusion, and
all of which contain suspended in them, either as essential or as
accessory elements, various solid and organized particles : the liquid
portion of some of these compound fluids exhibiting also a distinctly
organized constitution; as, for example, the liquor sanguinis and the
fluid parts of mucus and of pus.
The distinction referred to is not, however, without its use, and is
sufficiently well founded to serve the purposes of classification.
Of the Solids themselves it is unnecessary to make any formal sub-
divisions : they will simply be treated of in the order of their natural
relationship with each other.
Thus, the various solid structures entering into the constitution of
the animal organism will be described consecutively as follows, each
forming the subject of a distinct article : Fat, Epithelium, Epidermis,
Pigment Cells, Nails, Hair, Cartilage, Bone, and Teeth; the vari-
ous Tissues, the Cellular, under which head Ligaments and Tendons
will be described, the Elastic, the Muscular, and the Nervous,
including the description of the Brain and Nerves ; the Glands, Ves-
sels, Membranes ; and, lastly, the Pathology of the Solids, will be
treated of.
254 THE SOLIDS.
ART. VIII. — FAT.
The transition from the fluids to the solids would appear to be a
very easy and natural one through the substance about to be described :
thus, fat bears an evident relation to both the former and the latter,
remaining during life in a soft and semi-fluid state, and after death
becoming hard and solitl; it is, however, to the milk globules among
the fluids that it manifests the closest affinity, the fat vesicles, espe-
cially those of early life, and the milk globules resembling each other
in form, in appearance, and in the manner in which reagents act
upon them.
Fat is made up of the aggregation of a number of globules or ves-
icles, which some deem to be true cells, and which are held in juxta-
position by intersecting bands of cellular tissue; these vesicles, have
a smooth surface, semi-opaque texture, and they reflect the light in
the strongest manner.
Contents. — The contents of fat vesicles usually present a homoge-
neous appearance; sometimes nevertheless — as when undergoing
decomposition, and when they have been subjected to pressure — they
exhibit a granular aspect ; these contents are of an oily nature, and
chemists have detected in the lard of the pig the organic products,
oleine, stearine, margaric acid, a yellow colouring matter having the
odour and the nauseous taste of bile, and the chemical salts, chloride
of sodium, acetate of soda, and traces of carbonate of lime and oxide
of iron. It is probable that of these constituents the presence of the
chloride of sodium depended on the mode of preparation of the lard.
Form. — The form presented by the fat vesicles is various, but is
usually either globular, oval, or polygonal. The first shape is encoun-
tered in the fat of young animals especially (see Plate XVIII. fig. 1);
the second in that of adults (see fig. 2); and the third in situations
where the fat is subjected to considerable pressure, and on solidifica-
tion after death. The fat vesicles of the pig are described as being
elongated and kidney-shaped. This shape, however, is of rare occur-
rence, and cannot be regarded as the ordinary and characteristic form,
which is most generally more or less spherical or oval. Raspail,
observing this exceptional form, was led to institute from it an erro-
neous comparison between fat vesicles in general and the starch
granule.
FAT. 255
Size. — The fat vesicles of the adult are usually several times larger
than the solid corpuscles of any of the fluids described — the blood,
mucus, and milk; the size of the fat vesicles in any given quantity
of fat is not uniform ; but, like the globules of milk, varies exceedingly,
the dimensions of the larger vesicles surpassing several times those
of the smaller.
One exceedingly interesting law has been observed in reference to
the size of fat vesicles; thus, it has been ascertained that their
average magnitude increases from infancy up to adult age : in accord-
ance with this law, the fat cells of an infant will be found to be
several times smaller than those of a full-grown person, and those of
a child again of an intermediate size. This law will be apparent from
an examination of the figures given. (See Plate XVIII.)
Colour. — The colour of fat is subject to considerable variations,
but it usually exhibits a tinge, more or less deep, of yellow. The fat
of young animals is usually of a lighter colour than that of the full-
grown and aged; this may be seen by a comparison of the fat of an
infant with that of an adult, or of the fat of the calf with that of the
ox; in the former it is almost white, while in the latter it frequently
exhibits a deep and golden hue. The differences of colour referred to
doubtless denote differences in the relative proportion of the different,
constituents of fat.
In some animals, also, fat of various bright colours is encountered,
especially in Birds, beneath the skin of the beak and of the feet; in
the Crustaceae and in some of the Reptilia. In the Triton, the fat is
of a deep orange-colour, approaching to red. The coloration of the
iris of birds depends, according to Wagner, upon a fat which is
accumulated in drops, and perhaps also in cells.
Consistence. — The consistence of fat is different in different
animals, and also varies in accordance with the temperature; thus,
the fat of the pig is softer than that of the ox or sheep; that of the
human subject is intermediate between both in its consistence, and
all kinds of fat are harder in cold than in warm weather. The varia-
tion in the solidity of fats depends upon the amount of stearine and
oleine which they contain ; the hard fats containing a greater quantity
of stearine than the soft fats, in which the oleine is greatest.
Structure. — Most observers agree in assigning to each fat vesicle
a distinct investing membrane, notwithstanding which fact the proofs
adduced by them of the existence of such a structure are by no
means so decisive as to render such a conclusion any thing more
256 THE SOLIDS.
than doubtful: thus, micrographers, hitherto, have been unable to
demonstrate the presence around normal fat vesicles of an enveloping
tunic, but have been contented to rest their opinion upon the indirect
and uncertain evidence to be derived from a knowledge of the action
of reagents ; upon testimony, in fact, analogous to that upon which
Henle and Mandl decided in favour of the existence of a membrane
surrounding the milk globule.
Schwann, indeed, states that he found the membrane of the fat cell
to be almost as thick as the blood globule of man in an infant affected
with mollities ossium*
Henle also has observed around the obscure periphery of a fat cell
a strait and clear band, but could not assure himself that this was
not the result of an optical illusion. f
The above are the only trustworthy observations of a direct char-
acter recorded in proof of the existence of a distinct tunic to the fat
vesicle, and they are evidently not of a satisfactory or decisive nature.
The indirect testimony procured from a knowledge of the action of
reagents is as follows: Ether is stated to render the contents of the
fat vesicle fluid and transparent, without, at the same time, diminishing
its size, as is proved by the fact that on the resolidification of its
contents, the vesicle presents the same form and dimensions as at first.
Again, acetic acid, according to Henle, acts upon the fat vesicle
as upon the milk globule, destroying the membrane in different places ;
it permits the escape of a number of globules of oil or grease, which,
like pearl-drops, remain attached to the larger vesicle.
Ether, however, produces other effects than those usually described,
and which are mentioned above; thus, when applied to the fat
vesicles of the pig, many of them will be seen to burst, and to collapse
frequently to less than the fourth of their original size, losing, at the
same time, all definite form ; and, in proportion as the vesicle collapses,
one large circular drop, or two or three smaller ones, will be seen
gradually to form around and envelope the shrunken vesicle, which
is, however, never entirely dissolved.
There are other observers again, as Schwann and Henle, who
consider that fat vesicles are not merely provided with an envelope,
but that they are true cells, possessing both cell wall and nucleus.
Thus, Schwann noticed in the wall of the fat vesicles of the child
already referred to, a nucleus of round or oval form, sometimes
flattened, and sometimes not so.
* Mikroskopische Untersuchungen, p. 140, f Anal. Gen. p. 422.
FAT. 257
Furthermore, Henle writes, "very frequently the wall presents a
salient point on some part of its extent, and in that position exists a
nucleus, or a trace of a nucleus. Sometimes there are two nuclei,
and in very many cases they cannot be observed at all."*
Again, Mandl has made the observation in examining the fat tissue
of young rabbits, and especially in taking the little masses of fat
which lie along the vertebral column in the interior of the pectoral
cavity, that the vesicles appear but half filled, and that they consist of
two parts, an inner one conveying the aspect of a drop of oil, and an
outer membranous portion, f
Such are the facts hitherto recorded in favour of the presence of a
nucleus in the fat vesicle: it will be seen that although they are more
definite and satisfactory than those adduced in proof of the existence
of an investing membrane, yet that they are scarcely in themselves
sufficient to set at rest the question of its cellular nature.
The observations, then, cited above, while they fail to demonstrate
sufficiently the true organization of the fat vesicle, yet render it
extremely probable that it is really cellular. In favour of this view,
a few additional observations have occurred to myself, which are
conclusive on one of the two debated points of the organization of
the fat vesicle. The first have reference to the outer membrane. If
a thin slice of any of the softer fats placed between two plates of
glass be pressed firmly, though not with too great violence, and
subsequently be examined with the microscope, it will be seen that
the vesicles have not run into each other, but still preserve their
individuality.
Again, ether applied to the fat vesicle does not entirely dissolve it ;
even when it causes it to burst and collapse, a residue always remains,
and this probably is membranous.
Furthermore, if a thin slice of fat be placed between two plates of
glass, and having been forcibly compressed, be examined with the
microscope, it will be seen that some of the vesicles have burst,
discharging a portion of their contents, the membrane of the fat
vesicle then becoming visible, and declaring its existence by certain
folds and markings, into which it falls on the escape of its contents,
and by the jagged outline of the rent through which those contents
passed. (See Plate XIX. jig. 2.)
Finally, decomposition produces an effect somewhat analogous to
that occasioned by pressure; the fat vesicles burst, and their fluid
* Anal. Gen. p. 422. f Anaiomie Microscopique, p. 141.
17
258 THE SOLIDS.
contents escape, leaving the membrane in most cases entirely empty,
and which, as well the aperture in its parietes, may be easily detected
with the microscope ; the soft contents of the vesicles break up, and
resolve themselves into globules of an oil-like appearance. (See
Plate XIX. fig. 4.)
The second set of observations relate to the nucleus.
If a thin slice of the fat of the pig be pressed as before between
two slips of glass with a moderate degree of pressure, and then be
submitted to the microscope, in very many of the cells will be seen
a dark nucleus-like body- This experiment will not, however, always
succeed. (See Plate XIX. j%. 1.)
A body of a similar description, but of a more defined form, is very
frequently encountered in the decomposing cells of marrow fat; this
nucleated condition of the cells preceding their rupture. (See Plate
XIX. fig. 3.)
Again, in some fat cells contained in a small encysted tumour
removed from over the nasal bones, and kindly sent, to me for
examination by W. H. Ransom, Esq., of University College Hospital,
(to whose zeal and intelligence I am indebted for many interest-
ing specimens of morbid structure,) nucleoid bodies were distinctly
visible even without pressure, although they became more apparent
after a gentle degree of compression had been applied. (See Plate
XIX. fig. 6.) The apparent nuclei in the cases related differed from
each other somewhat, being more defined and darker in the two
latter than in the former; the cells themselves too were not identical
in appearance ; thus, the margins of those of the pig and of the
human marrow fat were smooth and distinctly defined, while those from
the tumour were less regular and distinct. (See Plate XIX. figs. 1 . 3. 6.)
Now these nucleus-like bodies in the several cases mentioned,
although occupying the position of nuclei and presenting the appear-
ance of such, it is very possible were not in reality true nuclei; it
seems to me that their formation might be accounted for without any
reference to a nucleus. Thus with respect to the nucleod bodies in
the cells of the pig produced by pressure, their formation might be
explained as follows : the mutual compression of the fat vesicles upon
each other would tend to occasion a condensation of the semi-fluid
contents in the centre of each, and in this way the appearance of
nuclei would be produced.
Again, the semblance of a nucleus in the decomposing cells might
be supposed to depend upon the partial escape by endosmosis of the
FAT. 259
contents of those cells, the portion remaining in them representing a
nucleus merely from the position occupied by it in the centre of the cells.
The formation of the nucleated bodies in the third case would seem
to point to and to require a different explanation. Decomposing fat
frequently exhibits a crystalline arrangement; now, it is conceived
that the outer part of each vesicle had become softened and broken
down, in consequence of commencing decomposition or of disease,
preparatory to its assuming the crystalline form, the central part at
the same time remaining unaffected.
It will be seen that the preceding observations, in relation to the
presence of a nucleus in fat vesicles, are not decisive, although they
add weight to those of anterior observers, and render it still more
probable that they are really nucleated cells.
The facts adduced, however, in reference to the existence of an
investing membrane are quite conclusive.
On the vesicles of decomposing human fat, it is a common occur-
rence to meet with stelliform figures, each being composed of a
number of delicate striae radiating from a central point. On the
smaller vesicles but a single figure of this description will usually be
met with, but on the larger there may be three or four. When but
one is present, it usually covers about a third of the surface of each
vesicle. (See Plate XIX. fig. 5.)
Henle* observes of these that they might be metamorphoses of the
nuclei of the cells; "nevertheless," he says, "they have more analogy
with crystalline deposits."
The occurrence of two, three, or four of these on the same cell is
opposed to the idea of their connexion with the nuclei; and the
observation of Mandl, who noticed their formation on butter, is con-
clusive on this point.f
Vogel,J as also Gerber,§ regard the figures in question as groups
of crystals of margaric acid.
Distribution. — The fat vesicles are distributed in groups, which lie
near to and follow the course of the blood-vessels. (See Plate XVIII.
fig. 1.) This arrangement is particularly evident in the mesentery
and omentum, and may be compared to that of a bunch of grapes, the
fat vesicles representing the grapes, and the vessels the stalks of the
bunch: in one particular only does the comparison fail; thus, each
* Loc. cit. p. 423. f Anat. Mia, f. 143.
% Arileilung zum Gebrauche des Mickroskops, p. 289. tab. 111. fig. 2.
§ Gerber's General Anatomy, translated by Gulliver.
280 THE SOLIDS.
grape of the bunch receives and is attached to a separate pedicle,
which is not the case with the fat vesicles, although one observer has
asserted that a separate vessel is distributed to each vesicle. The groups
of fat vesicles occurring in young animals, in which each globule is
circular, may be compared to heaps of shot piled up upon each other.
In those situations in which the fat occurs in thick and dense masses,
the arrangement referred to is- somewhat different. The fat vesicles
are still parcelled out into groups by means of intersecting cellular
bands ; but the several groups lie in close contiguity, instead of being,
as in the former case, separated from each other by distinct intervals.
Thi'oughout these masses, too, but few blood-vessels are distributed.
The intimate arrangement of the fat vesicles having been thus
briefly sketched, it remains to describe the general distribution of fat
throughout the body.
In man, fat is developed principally in the loose cellular tissue ; it
is encountered forming a layer of variable thickness in that which is
situated immediately beneath the skin; in the serous membranes, as
in the omenta, the mesenteries, and the epiploa; on the surface of
the heart, and around the kidney.
In certain situations the sub-cutaneous fatty layer experiences an
increased development designed to fulfil certain peculiar intentions;
thus, in the soles of the feet, the palms of the hands, in the female
breast, in the region of the pubis, and over the glutei muscles, espe-
cially over those of the Hottentot women, fat is developed usually in
considerable quantities.
This superficial layer of fat is also generally thicker in children
and in women than in men.
Again, there are other peculiar situations in which fat is almost
invariably encountered, as in the orbit, in the articulations, where it
constitutes the glands of Havers, in the shafts of the long bones
forming the marrow, in the vertebral canal, and in many other
localities where vacancies occur which require to be filled up. The
marrow differs only from ordinary fat in that the cells composing it
are more circular, with but little admixture of cellular tissue.
On the other hand, there are situations in which, under no circum-
stances, is fat developed, as in the eyelids, in the axillae, between
overlapping muscles, and in the genital organs.
Quantity. — The amount of fat varies greatly in different species of
mammalia, in different individuals of the same species, and in the
same animal at different times.
PAT. 261
Thus, certain animals seem to have a peculiar aptitude for the
formation of fat, as the pig.
Again, the various members of one family are sometimes observed
to be remarkable for the constitutional predisposition exhibited to the
formation of fat. Again, other families are met with equally remark-
able for their indisposition to fatten.
Lastly, in some animals the fat accumulates at particular periods
in greatly increased quantities, as in the hibernating mammalia, and
in the. larvae of insects. In man the fat usually undergoes an aug-
mentation after the meridian of life has been passed.
Castration peculiarly predisposes the system to the formation of fat.
Occasionally, also, fat is secreted in vast and abnormal quantities :
where this augmentation is general, it constitutes the diseased condi-
tion of obesity; and where it is only partial, it gives rise to tumours,
often of great magnitude.
In general, a certain degree of fatness argues a healthy and vigorous
condition of the system, while its excess or inordinate accumulation
denotes either a degree of weakness of constitution or a peculiar and
unexplained state of the system.
Disappearance. — Of all the solids in the body, fat is developed and
destroyed with the greatest rapidity: in illness, it disappears with sur-
prising quickness, and is formed again, under the influence of recovery,
with almost equal celerity.
The exact changes which occur during the disappearance of fat
are unknown; whatever they may be, they doubtless affect each
individual fat vesicle throughout the body, and their nature being
ascertained in a single cell would serve to explain the disappearance
of fat over the entire body. It is uncertain whether the contents of
the vesicle disappear, the membrane remaining, or whether both are
effaced together. Beclard says that the fat vesicles themselves disap-
pear.* Hunter, on the contrary, assures us that they may be distin-
guished even when they are empty. f Gurlt states that they contain
serosity in place of grease in lean animals. J
The immediate cause of the disappearance of fat most probably
depends upon interrupted nutrition ; the contents of the cells escaping
through their walls become absorbed by the lymphatics, and thus
removed into the circulation. This view is supported by the observa-
* Analomie Generate, p. 163.
f "Remarks on the Cellular Membrane," in Med. Obs. and Inq., vol. ii., Lon., 1757.
I Physiologie, p. 20.
262 THE SOLIDS.
tion of Henle, who states that, after repeated losses of blood, the quan-
tity of grease in the blood augments considerably, on the surface of
which it is often seen swimming as a cream or pellicle.
Uses. — The uses of fat are manifold and important.
1st. It serves to impart softness to the texture of the skin.
2d. It adds grace and symmetry to the outlines of the body.
3d. In certain situations, as in the soles of the feet, in the palms of
the hands, and over the glutei muscles, it serves as a protection against
the effects of pressure.
4th. Being a bad conductor of caloric, it prevents the too rapid
dissipation of the heat generated in the system.
5th. It is to be regarded as a reserve store of nourishment set apart
by the system during the period of its health and strength, and
designed to meet certain exigencies, when the inhei'ent powers of the
constitution are called into requisition, as in times of hunger and
sickness.
Distinctive Characters of Oil Globules. — The contents of fat ves-
icles are, as already stated, of an oleaginous nature, which, when they
escape from the vesicles, assume the form of oil drops; these are often
met with in the various fluids and solids of the system apart from the
fat vesicles, from which it is necessary that they should be discrimi-
nated. There are several characters by which oil globules may be
distinguished from true fat vesicles; thus, they are of a fluid nature,
are usually perfectly spherical, and, on account of their fluidity, in
place of being globular, are generally flat; they are seen sometimes
to alter their shape, as when they roll over on the surface of the
object-glass, or come in contact with obstacles; they reflect the light
less powerfully, and, lastly, the slightest degree of pressure causes
them to coalesce.
There is but little probability of confounding oil globules with air
bubbles ; these have a different colour, reflect the light differently, and
are perfectly globular.
See Appendix, page 538.
FAT. 263
PAT.
[No farther hints are necessary on the preparation of fat for examination,
or the use of reagents while under examination, than those given in the text.
In order to display the blood-vessels of the fat vesicles, their injection is
necessary. These vessels are represented in Plate LXX., fig. 3, and their
existence is referred to in the Appendix, page 538.
These vesicles can only be injected when the injecting material is very
fine, and the operation is perfectly successful. In those instances in which
the papillae of the skin are well injected, the fat vesicles will also be found
more or less completely injected ; the injection must be made from the
main vessel, usually the vein, that supplies the part.]
264 THE SOLIDS.
ART. IX. — EPITHELIUM,
As the external surface of the body is invested with a cuticle which
has received the name of Epidermis, so are its internal free surfaces
in like manner clothed with a delicate pellicle which has been denom-
inated Epithelium.
Both the epidermis and epithelium are constituted of cells : there is
this difference, however, between them, that while the former, by the
intimate union and super-imposition of its cells, exists as a distinct and
continuous membrane, the latter, owing to the feeble cohesion of its
constituent cells, can scarcely, except in certain situations, be shown
to exist as a united and extended structure.*
The epidermis and epithelium are, therefore, hardly to be regarded
as distinct structures, but rather as the same, the differences observed
between them being merely modifications, the result of the different
circumstances to which they are each subject.
The essential identity of the two may be shown by an examination
of the epidermis at the outlets and inlets of the body, where, by gradual
transition, it may be traced inwards into the condition of epithelium;
and this, also, traced from within outwards, will be observed gradually
to acquire the characters of epidermis; so that, within a certain dis-
tance of the termination of the cavities of the body, which open
externally, the epithelium may also be demonstrated as a distinct
membrane; this membrane may be followed in man from the lips as
far backwards as the posterior part of the mouth, also passing over
the tongue; and in the horse and in birds it may be shown to exist in
the stomach and gizzard.
The epithelium will be first described, inasmuch as its organization
would appear to be more simple than that of the epidermis, which, by
modifications of its cells, is converted into so many apparently distinct
structures.
It has been remarked that the internal free surfaces of the body are
covered by epithelium: these surfaces comprise those of both the
* Leeuwenhoek first discovered in the mucus of the vagina little scales, which he
presumed formed the internal membrane of that canal, and from which he conceived
they become detached by coitus. (Opera,t. i. p. 153. 155.) He likewise noticed that
the mucus of the mouth contained scales, (Ibid. t. hi. p. 51,) and he saw also the
cylindrical epithelial cells of the intestinal cavity. (Ibid. p. 54. 61.)
EPITHELIUM. 2G5
open and the closed cavities, the former of which include the aliment-
ary canal from mouth to anus, the genito-urinary organs and passages
of both the male and female, and the respiratory track, consisting of
the trachea, bronchi, cells of the lungs, and nares; the latter consist
of the great serous sacs of the head, chest, and abdomen, and the lesser
ones of the pericardium, tunica vaginalis, the cavities of the joints,
and of the lymphatic and blood vessels, including the heart.
The bursas are said by Henle* not to be furnished with an investing
epithelium — a statement to be received with some degree of hesitation.
It would appear, therefore, that, with the single doubtful exception
alluded to, every free surface of the body is invested with its own
appropriate epithelium, the ventricles of the brain even being lined
with an epithelium proper to them, and the surface of the cornea being
covered with one also. The existence of an epithelium in this latter
situation may be directly proved by means of the microscope : and it
may be inferred from the observation of the fact, that in the general
casting of the epiderm of snakes and other reptiles, a delicate film is
likewise thrown off from the surface of the cornea.
The epithelium has not the same character in the different situ-
ations in which it is encountered, but the cells of which it is composed
differ in form and size, according to age and the locality occupied by it.
The several varieties of epithelium may be reduced into two prin-
cipal types, in the first of which the cells are more or less circular or
polygonal, and in the. second are elongated and conoid. These two
forms may be distinguished by the appellations of Tessellated or Pave-
ment Epithelium, and Cylindrical or Conoidal Epithelium. (See
Plate XX. figs. 1 and 2.)
The Conoidal Epithelium admits of sub-division into Naked
Conoidal Epithelium and Ciliated Conoidal Epithelium.
TESSELATED EPITHELIUM.
Form. — The cells of this description of epithelium form many
layers, are flattened, and either circular, polygonal, or irregular in
outline: the younger cells are mostly of the first shape, and are
thicker than the older ones, which are irregular in form, thin and
membranaceous, while the polygonal cells are encountered more
particularly in certain situations, as on the choroid plexus, pericar-
dium, and serous membranes in general. The polygonal shape is
* Anal. Gen. vol. vi. p. 225.
266 THE SOLIDS.
produced by the mutual compression exerted by the cells upon each
other, and consequent adaptation.
Size. — The size of the cells of pavement epithelium varies both
according to age and locality; the younger and deeper seated cells
are of course smaller than the older and more superficial ones; the
larger cells are met with in those situations where the epithelium is
continuous with the epidermis, as in the mouth and oesophagus, the
vagina, urethra, and bladder, the commencement of the rectum, the
inferior division of the nares, lining the eyelids, and covering the
cornea. (See Plate XX. Jig. 1.) On the contrary, the epithelium
of the pericardium, ventricles, aorta, and of most of the closed cavi-
ties, is composed of cells which are very much smaller in size than
those of the localities previously enumerated. (See Plate XXII.)
Structure. — Epithelial cells illustrate faithfully the doctrine of cell
development, each consisting of a nucleus, cell wall, and intervening
space enclosing fluid, both the nucleus and the cell wall exhibiting a
granular composition.
It has been observed, that the younger cells are thicker than the
older and fully developed ones, which become reduced to mere mem-
branous expansions, from which it follows that the space intervening
between the nucleus and cell wall is greatest in the younger cells,
while it is almost obliterated in the older. The smaller cells are also
more granular than the larger : now, these two facts stand in close rela-
tionship with the function discharged by these cells, and which is so
much the more active as the cavity is large and the granules numerous.
The nucleus is likewise best seen in the younger cells: in the older
ones it becomes either entirely obliterated, or it escapes from the
cavity of the cell, the position which it previously occupied in it
being indicated by a depression; it is for the most part circular; but
occasionally, and particularly in certain localities, it is found to be
oval, as in the epithelium of the lower two-thirds of the uterus, in
that of the pericardium, and also in that of the blood-vessels, the
aorta excepted ; it sometimes occupies a central position in each cell ;
at others it is eccentric.
The properties of pavement epithelial cells, as well as their form,
size and granular texture, alter also with age : thus the younger cells
are dissolved, with the exception of the nucleus, by acetic acid, while
the same reagent applied to the older ones produces scarcely any
appreciable effect.
Epithelial cells, on the addition of water, or after death, become
EPITHELIUM. 267
white and opaque — a common effect of water on all animal struct-
ures. The change in the case of the epithelial cells probably depends
upon the coagulation of their fluid contents; and to it the character-
istic dulness of the eye after death is due.
Distribution. — This form of epithelium is more extensively dis-
tributed than the conoidal variety: it is encountered on the free and
serous surfaces of all the closed cavities, as of the cranium, thorax
and pericardium, abdomen and tunica vaginalis, lining the lymphatic
and blood vessels; even the ventricles of the brain itself, in which it
rests immediately upon the cerebral substance, are not free from it:
it is met with likewise near the terminations of those cavities which
open externally, as in the mouth, where it extends as far backwards
as the cardiac extremity of the stomach, in the lower portions of the
nares, whence it passes into the frontal sinuses, in the vagina and uterus,
the lower two-thirds of which it lines, as also the urethra. In the male
subject it passes over the glans penis, and then enters the urethra.
The epithelium of the urinary apparatus should perhaps be referred
to the pavement epithelium : its cells, however, vary very consider-
ably in form: thus, many of them decidedly resemble the variety of
epithelium under discussion ; others, however, are clavate, the narrow
or fixed extremity being often produced into a long thread or filament;
and again, others imperfectly represent the conoidal variety of epithe-
lium; these last, as well as the clavate cells, are met with in the
greatest quantity in the upper part of the bladder, and in the ureters.
CONOIDAL EPITHELIUM.
Form and Size. — The cells of this form of epithelium are much
more regular in size and shape than those of the tesselated or pave-
ment kind : the term cylindrical usually applied to them is, however,
far from accurate, since they do not possess, even in a slight degree,
the outward form of a cylinder : the word conoidal, here used, serves
to express much more closely the real form of the cells of this variety
of epithelium, although it fails to give an exact idea of their shape:
thus, the cells in question are not merely conical with flat summits,
but each cone is flattened at the sides, so that when the bases of the
cones are seen directly, they exhibit the appearances of ordinary
polygonal tesselated epithelium; the side view of the cells will at
once make manifest their distinctness. (See Plate XX. Jig. 2.)
Conoidal epithelial cells are usually disposed more or less vertically
to the surface upon which they rest, their narrow extremities being
268 THE SOLIDS.
turned downwards, and attached to that surface, and the broader and
free ends being directed upwards.
Structure. — The cells of conoidal epithelium have precisely the
same structure as those of the previously described kind; that is,
they consist of nucleus, cell wall, granules, and fluid contents: the
chief difference is one of form and not of structure.
The nucleus is almost invariably oval, the long axis corresponding
with that of the cell itself: it is often so large as to occasion the cell
to assume a ventricose form, it being contracted immediately above
and below the part in which the nucleus is situated. Some observers
speak of two nuclei in a single cell: this, however, must be an
exceedingly rare occurrence, as I have never yet met with a single
example of the kind.
The conoidal epithelium is, as already remarked, divisible into
two kinds.
Naked Conoidal Epithelium.
Distribution. — This sub-division of epithelium, to which the des-
cription just given more immediately applies, is met with investing
the mucous membrane of the alimentary canal, extending from the
cardiac extremity of the stomach to within two or three inches of the
rectum; it is encountered likewise lining the several ducts and prolon-
gations which communicate with this: thus, this form of epithelium
exists in the gall-bladder, where it is of a deep yellow colour, in the
ductus communis choledocus, in the pancreatic duct, and in the
mucous crypts or follicles imbedded in the mucous membrane; It is
found also in the upper portion of the nares, in the salivary ducts, in
the appendix vermiformis, and in modified form in the vas deferens.
In the stomach, the naked conoidal epithelium does not exist in an
unmixed form ; it occurs intermixed with pavement epithelial cells,
probably derived from the oesophagus, and carried down during
deglutition.
It is in the gall-bladder, the small intestines and the appendix
vermiformis, that the naked conoidal epithelium exists in the greatest
perfection,
Ciliated Conoidal Epithelium.
The cells of this variety of conoidal epithelium agree precisely in
form, size, and arrangement with those of the first described sub-
EPITHELIUM. 209
division, the only difference being, that they are possessed of the
singular addition of vibratile cilia.* (See Plate XXI. jig. 3.)
The cilia taper from base to apex, and are attached to the thick-
ened margins of the summits of the cells, ten or twelve of them
belonging to each. In the frog they would appear to be not merely
attached to a circular line, but also to the segment of the cell
described within this. (See Plate XXI. jig. 1.)
During life, the cilia are in a constant state of activity: the power
by which their motions are effected is, however, involved in the
greatest obscurity: it can scarcely be the result of muscular structure,
as some have supposed, since the entire cilium is many times smaller
than the smallest muscular fibre. The idea has been put forth that
the cilia are hollow; that they communicate with a vessel which
runs along their bases, containing fluid ; and that they are moved by
the successive injection and expulsion of this fluid.
One fact has been observed, which affords countenance to the
above explanation of the motion of the cilia, viz : that this takes
place in a determined direction : commencing in the cilia on one
side, it runs along them to the opposite, the several cilia being thus
successively called into action. It is this peculiar character of the
motion of the cilia which has led to its comparison with the waving
of a corn-field over which the wind passes in successive gusts. The
motion, in whatever way effected, is singularly beautiful, and, strange
to say, exhibits many of the characters of volition : thus, it will some-
times cease altogether for a time, and then suddenly commence again.
It is also sufficiently powerful to effect the entire displacement of the
cell or corpuscle to which the cilia are attached, and many of which
may frequently be seen moving freely and quickly about, usually in
circles, in the field of the microscope. This curious spectacle is
most readily witnessed in the ciliary cells of the trachea of the frog,
which are of a different form from those of the mammalia, being
rounded in place of elongated and conoidal. (See Plate XXI. jig. 1.)
The combined motion of the cilia is also capable of putting in
movement either fluids or solid particles which may come into contact
with them. This fact those who are given to microscopic investi-
* To Purkinje and Valentin especially belong the honour of making known in all
its extent the phenomenon of ciliary motion, and which before that time had been
observed only in some few of the lower animals, and concerning the nature of which
many errors prevailed. They discovered it in the respiratory and female genital
organs in 1834. (Mailer, Archiv. 1834, p. 391.)
270 THE SOLIDS.
gation will have had many opportunities of verifying, and one may
easily at any time acquire the proof of it by mixing with the fluid in
which the cilia are acting some fine powder, as, for example, of carbon.
The motion of the cilia, when acting in combination, is stated to
take place always in a determined direction from within outwards.
It would appear, however, from the observations of Purkinje and
Valentin* that the direction is capable of reversion : thus, these
observers saw the accessory branchiae of the anodon vibrate during
from six to seven minutes in one direction, and afterwards, during
the same lapse of time, in an opposite.
The influence of physical and chemical reagents upon the vibratile
movement has been carefully examined. Thus, if a portion of
vibratile epithelium be touched or scraped, the motions of the cilia will
become more active, and sometimes commence again even after they
had become extinct. They cease at a temperature below the freezing
point, and at a degree of heat sufficient to occasion the coagulation
of the animal fluids. Galvanism destroys their action, but in a local
manner — a fact which a reference to the constitution of epithelium
by the union of separate cells may serve to explain. Among chemical
reagents, narcotics are without influence; acetic and the mineral
acids destroy the motion, as also caustic ammonia, nitrates of potash
and of silver. The serum of the blood prolongs its duration. Urine
and white of egg are without effect upon it. Bile instantly destroys
the activity of the cilia.
The ciliary motion soon ceases after death in the mammalia, but
continues in many of the invertebrata, and especially in several of
the mollusca, as, for example, in the river muscle and the oyster, for
days after the death of the animal.
It would appear, therefore, that each ciliated corpuscle bears the
closest possible resemblance to many of the infusory animalcules,
and it is questionable whether its claim to be regarded as a distinct
entity be not equally strong.
Distribution. — Ciliated epithelium has not been as yet discovered
among the mammalia in any closed cavity, but always in situations
which communicate with the air; thus, it is met with, as is generally
known, lining the trachea and bronchi, extending even to their
minutest ramifications ; again, it is encountered in the Fallopian
tubes, and lining the upper third of the cavity of the uterus of adult
animals, but not that of young mammalia. There is yet another
* Motus Vibrat., p. 67.
EPITHELIUM. 271
locality in which I believe it also to exist, viz: in the convolutions of
the tubuli serniniferi of the epididymis.
On the other hand, there are many situations in which it has been
repeatedly asserted to exist, but in which patient and repeated inves-
tigation has failed to reveal its presence; as, for example, in the
ventricles of the brain,* covering the pia mater, and lining the eyelids
and frontal sinuses.f
The epithelium of these several parts, on the contrary, is pavement
and not ciliated epithelium. (See Plate XXIV.)
Purkinje,J in describing the epithelium of the ventricles, does so
most circumstantially, and states that he followed the vibratile move-
ment in the sheep from the lateral ventricles through the third
ventricle, and by the aqueduct of Sylvius into the fourth.
Valentin § confirms the accuracy of this description as regards man.
We find Henle|| describing the epithelium of the ventricles as a
cuneiform ciliated epithelium; and in Gerber's General Anatomy,
we remark that it is stated to be a tesselated ciliated epithelium. It is
singular how so great an error could have originated, and still more
so how it could have been so long perpetuated.
DEVELOPMENT AND MULTIPLICATION OF EPITHELIUM.
I
Each epithelial cell is first detected as a nucleus without any
appearance of cell wall around it: this, however, may exist, closely
embracing the nucleus, even from the earliest period at which this
can be observed. After a time, however, a transparent border
becomes visible, surrounding the nucleus: the width of this goes on
gradually increasing, until at length the full dimensions of the cell
have been attained: now, the outer limit of this border doubtless
indicates the cell wall, the clear space between it and the nucleus
being in the younger epithelial cells filled with fluid. In the conical
epithelium the cell wall is not developed equally around the nucleus
as in the pavement epithelium, but chiefly in two opposite directions.
It has been observed, that young epithelial cells are thicker and
rounder than the older ones ; it has also been remarked, that they are
more granular; facts which stand in close relation with their func-
tional activity.
It has been noticed likewise, that the nucleus in the progress of
* Purkinje in Miiller, Archiv. 1836, p. 289.
f Henle, Anat. Gen. t. vi. p. 252. \ Miiller, Archiv. 1836.
\ Repertorium, 1831, p. 158. 278. || Anat. Gen. tvi. p. 253.
272 THE S O L I D 3 .
development becomes either obliterated, or that it escapes from the
cell. Now, it has struck me that this disappearance of the granular
nucleus and granules of the cell wall might possibly be connected
with the reproduction or multiplication of epithelial cells, as well as
of cells occurring elsewhere than in the epithelium, and that each
granule might in reality be an epithelial cell in embryo. This is of
course but a conjecture: it is one, however, which would appear not
to be contradicted by any other known fact, and to have analogy in
its favour; the mode of reproduction among the lower algee being
precisely similar.
The occurrence of two nuclei in the same cell has been recorded
by some observers, and who have from this fact drawn the inference,
that epithelial cells are multiplied by division. This method of
increase cannot, however, be presumed to prevail to any extent, since
it is a circumstance of extreme rarity to meet with two nuclei in the
same cell.
NUTRITION OF EPITHELIUM.
The epithelium has no immediate or structural connexion with the
parts which lie immediately beneath it, neither does it receive blood-
vessels and nerves from those parts ; it is simply dependent upon them
for the supply of nourishment, of which it is the recipient, and which
is derived from the blood-vessels distributed throughout the tissue of
the true skin lying beneath it, and from which vessels the plasma is
continually escaping by transudation or exosmosis.
DESTRUCTION AND RENEWAL OF EPITHELIUM.
The epithelium in every part of the body is continually undergoing
a process of destruction, and consequent renewal.
It is less easy to establish the fact of the destruction of the epi-
thelium in the closed cavities than in the open; nevertheless, that it
really does take place even in these, may be inferred from the observa-
tion of the fact that the cells of epithelium encountered in such local-
ities represent every degree of development, many of the older ones
also being destitute of nuclei, and more or less broken into fragments.
It is probable, however, that the process of destruction is slower in
the closed than in the open cavities.
In the open cavities, the destruction of epithelium is doubtless more
considerable and more rapid; it is also more easy to determine in
these; thus, during mastication, deglutition, and digestion, a consider-
EPITHELIUM. 273
able amount of epithelium becomes disturbed, removed from the sur-
face to which it was attached, and mixed up with the saliva, mucus,
gastric fluid, food, &c, and finally is discharged from the system with
the faeces, in which, by microscopic examination, it may readily be
detected.
The fact of the gradual and continual destruction of epithelium
may likewise be ascertained by an examination of the several fluids
discharged from the system, as the saliva, the mucus, from either
mouth, nose, lungs, urine, seminal or menstrual fluids, in all of which
the microscope will reveal an abundance of epithelial cells.
The same fact may also be determined by a microscopic examina-
tion of the scum which collects during the night on the lips and
around the base of the teeth of many persons.
In certain situations the epithelium undergoes not merely a gradual,
but also a periodical destruction, as in the uterus at the monthly
periods and after parturition.
The continual destruction of epithelium having been thus rendered
manifest, its renewal follows as a matter of necessity.
In irritation of the mucous membrane of the bronchi, nose, and
alimentary canal, it is possible that the epithelium, during the period
of the continuance of the irritation, is entirely destroyed.
. USES OF EPITHELIUM.
* The first use of the epithelium is a passive one, it serving like the
epidermis as a protection to the more delicate parts which lie imme-
diately beneath it.
The second use is active, the epithelium doubtless being an import-
ant agent in secretion.
Each epithelial cell may be regarded as a gland reduced to its most
simple type or condition, it embodying all that is essential in the
largest and most complex secreting organ, viz: the true secreting
structure.
The nature of the fluid secreted by epithelial cells is not every
where identical, but varies according to their exact structure and the
locality in which they are found : thus, in some situations, they secrete
serum, as in the serous sacs : in others mucus, as in the mouth, nose,
alimentary canal, &c; in others synovia, as in the joints; in the
stomach and in the duodenum, they assist in the elaboration of the
fluids which are there found.
That the epithelial cells are the real agents engaged in the pro-
18
274 THE SOLIDS.
duction of the several fluids named, is rendered certain by the facts
that they correspond precisely with the undoubted secreting structure
of true glands; and further, that in the situations where they are
found, no other organization exists to which the function of secretion
could with any degree of probability be assigned.
• The importance of the office discharged by the epithelium explains,
then, the universality of its distribution.
The diffusion of epithelial or secreting cells over the surface of
membranes which require to be kept continually moistened by a suit-
able fluid, affords a beautiful example of the wise adaptation of means
to an end: by no other means than that employed could the end in
view be so surely accomplished, or with so great an economy of space.
The above-described uses of epithelium are common to it wherever
encountered: the third use is mechanical, and accomplished only by
the ciliated form of epithelium.
It has already been observed that the force of the combined action
of the cilia is so great as to enable them to carry along with or drive
before them fluids, and even solid particles which may happen to come
in contact with them : it has likewise been remarked that the direction
of their united action is invariably from within, outwards or towards
the outlets of the body; at least it is so among the mammalia. From
a knowledge of these facts it is not difficult to suggest the probable
use of vibratile epithelium in the localities in which it has hitherto
been discovered in man and the mammalia.
Thus in the bronchi and trachea, it may be presumed to be
designed to facilitate the escape from those passages of any foreign
particles which may have found entrance to them.
Again, in the Fallopian tubes and upper portion of the uterus, it can
scarcely be questioned, but that its use is to hasten the progress of
the ovum from the ovary to the uterus; and, presuming that the
direction of the action of the cilia may be, and is sometimes reversed,
the vibratile epithelium of these parts may be further intended to
ensure the more speedy transmission of the seminal fluid along the
Fallopian tubes to the ovary, upon which it has been detected by more
than one observer.
EPITHELIUM. 275
EPITHELIUM.
[Microscopic examination has revealed . the fact that many tumours
supposed to be cancerous, especially certain tumours about the lips, were
composed of degenerated epithelium. Ecker* has described these tumours
of the lip, and denominated them bastard cancer of the lip. It is now
ascertained that these tumours are not confined to the skin, but occur in the
mucous membranes. Rokitansky has found them on the lining membrane
of the larynx, trachea, stomach, intestines, and bladder. They may be also
met with on the dorsal aspect of the hand, on the cheeks, scrotum, prepuce,
and it may be the chimney-sweep's cancer is but an epithelial tumour.
Lebert regards them as benign, since they contain no cancer-cell. Roki-
tansky and Bruck consider them malignant. Dr. Gorup Bezanes regards
the important question to be, not whether these tumours may be benign, but
whether they are altogether exempt from malignity: his observations con-
firm the opinion of their malignity.
See Archiv. Gen. de Med. torn xxm. p. 76, Mai, 1850.
See also Dublin Quart. Jour. August, 1850, p. 255.
PREPARATION.
The text has already indicated the different localities from which the
various forms of epithelium may be obtained.
The pavement or scaly epithelium may be best studied by scraping any
of the serous membranes gently with a knife, and examining the particles
removed. Many of the cells after removal will be found to adhere together.
The addition of a little weak ascetic acid will render the angles of the
scales more apparent.
The conoldal variety of epithelium is easily obtained by macerating any
of the mucous membranes, as, for instance, a portion of the alimentary canal.
By this process, the epithelium becomes detached, and may be collected and
viewed with the microscope. The ciliated variety possesses most interest.
The cilia may be seen in motion by taking a small piece of the mantle of
an oyster or mussel, folding it upon itself, and placing it under the micro-
scope so as to allow the cilia to project. The edge of the beard will also
show the cilia in motion. The fragment should be moistened with water,
and covered with thin glass; a power of about 250 diameters is necessary
for good observation. The currents caused in the water by the cilia in
motion may be readily detected by the suspension of fine particles of car-
mine or charcoal in the water. These particles are first seen attracted by
the ciliary motion, and then repelled.
* Archiv. fur Physiol Heilkunde, 1849.
276 THE SOLIDS.
In quadrupeds the ciliary motion may be observed by taking a small
portion of ciliated mucous membrane from an animal recently killed, and
folding it in the manner already indicated^
In man the cilia may be seen in motion in recently detached nasal polypi.
They may also sometimes be discovered in mucous discharges.
The ciliary motion may be studied on a larger scale in many of the fresh-
water infusoria, so abundant during the summer and fall months in small
ponds and stagnant pools.
Epithelial cells may be preserved in the flat or thin glass cell, suspended
in a weak solution of chromic acid, or Goadby's B-solution.]
EPIDERMIS. 277
ART. X. — EPIDERMIS.
The entire of the external surface of the body is invested with a
membrane which has been denominated epidermis, formed of super-
imposed layers of nucleated cells (see Plate XXIV. fig. 3), and the
number of which layers is greatest in those situations in which the
membrane is subject to the most pressure, as in the palms of the
hands and soles of the feet, in which the epidermis sometimes attains
the thickness of the TV, or even the \ of an inch.*
The form, structure, and development of the cells composing the
epidermis are in every respect identical with those of the tesselated
variety of epithelium already described; thus, first, the younger and
deeper-seated cells are spherical in outline, and almost globular, while
the older and more superficial cells become irregular in form, expanded,
thin, and membranaceous ; secondly, like those of the tesselated epi-
thelium, the cells consist of a nucleus, cell-wall, cavity, and granules;
it is, however, worthy of remark, that the nucleus, as well as the
majority of the granules contained in the epidermic cells, disappear
at an earlier period of development than do those of the epithelium —
facts which will be explained when the uses of the epidermis come to
be treated of; thirdly, the plan of development is the same in the two
cases, the cell-wall being developed around the nucleus, which is the
part first formed.
Thus far, then, there is a close correspondence between the epider-
mis and epithelium ; so close, indeed, as to make it apparent that the
two are but modifications of one and the same structure. The chief
respects in which it diners from the epithelium are in the compact
and firm union of the cells with each other, whereby it forms a distinct
and continuous membrane, and in the paucity of granules dispersed
throughout the cells.
The epidermis also stands in precisely the same relation with the
parts beneath it as the epithelium; thus, it has no structural con-
nexion with those parts, and receives neither blood-vessels nor nerves
from them, but is simply dependent upon them for the plasma which
is continually escaping from the blood-vessels of the true skin. This
* Leeuwenhoek first observed that the epidermis was composed of scales placed
one against the other, and also that, after a certain lapse of time, they were cast off,
and their place supplied by others.
278 THE SOLIDS.
want of structural connexion is shown by the fact that a portion of
the cuticle may be detached without its removal occasioning either
pain or hsemorrhage.
This separation of the epidermis from the dermis frequently takes
place during life, as from a burn, scald, or blister, or from the effusion
of serum, the result, not of injury, but of disease. After death, and
on the commencement of decomposition, the epidermis may be
detached in large masses, the prolongations sent down to the sebace-
ous and sudoriferous glands also coming away with it.
The epidermis does not merely cover the whole external surface
of the body, but sends processes into its various outlets, as the mouth,
nose, rectum, vagina, and male urethra ; these prolongations soon lose,
however, the characters of epidermis, and acquire those of epithelium.
The epidermis likewise sends down processes into the sebaceous
and sweat glands, and which, forming a perfect tube, serve to convey
the secretions of those glands to the surface, on which they open as
raised and rounded papillae, with central depressions and apertures.
(See Plate XXIII. figs. 1 and 2.)
A sheath of epidermis likewise encircles the base of each hair.
The number of these infundibuliform processes and salient papillae
which open on the surface is immense, and may be stated at about
3,000 to the square inch, which, computing the number of square
inches of surface in a man of average size at 2,500, would give
7,500,000 for the entire surface of the body.
In addition to the papillae, we observe on the surface of the epider-
mis a great number of lines or furrows which map it out into a net-
work of small polygonal and lozenge-shaped spaces ; these are of two
kinds, the one large and coarse, and corresponding with the flexures
of the joints; the others smaller, occupying the interspaces between
the larger, and also being generally distributed over the surface of the
epidermis, where the articular furrows have no existence. The plan
of arrangement of the smaller lines is as follows: A number of straight
lines, usually from six to ten, radiate, like the rays of a wheel from its
centre, from each hair-pore; these usually come in contact with the
lines proceeding from other hairs. These radiating lines thus mark
out the surface into triangular spaces, between which are usually
situated two or three other pores, those of the sebaceous and sweat
glands; from each of these also similar radiating lines proceed; these
unite with the coarser lines given off from the hair follicle, and occa-
sion a still further sub-division of the surface of the epidermis into
triangular spaces. The result of this minute sub-division is to occasion
EPIDERMIS. 279
the whole surface of the epidermis to assume a minutely and beauti-
fully reticular appearance. The coarser lines are best seen in the
palms of the hands and soles of the feet, while the smaller and finer
lines may be readily traced, following the disposition just described on
the back of the hand.
The effect of water in rendering the cells of tesselated epithelium
white and opaque has been referred to: its long-continued application
to even the living epidermis produces a similar result, which most
persons must have observed, although some would be at a loss to
account for it; thus, the skin of the fingers of those who have been
engaged in washing for some hours becomes of a pearly whiteness.
It sometimes happens that epidermic cells are developed in increased
and abnormal quantities, giving rise to tumours, and which are by no
means of uncommon occurrence.
EPIDERMIS OF THE WHITE AND COLOURED RACES.
Between the epidermis of the white and the coloured races there is
a perfect identity of structure ; the only difference is, that the young
epidermic cells of whites contain little or no colouring matter, or
pigment granules, except in certain situations, while those of blacks
are filled with them; this difference can scarcely be regarded as per-
manent or structural ; it is one rather of degree than kind, and over
which, moreover, climate exerts an all-powerful influence.
We have continual opportunities of witnessing the effect of climate
in increasing .the amount of pigmentary matter in the skin. All have
noticed that after a few years' residence in a hot country, the skin of
many individuals becomes several shades darker than it was pre-
viously, and that even the inhabitants of the same country are darker
during the summer than in winter.
It would appear, therefore, to be very possible that climate alone,
operating through many ages, would be sufficient to change the colour
of the skin from white to all the varying shades of red, olive, and black,
met with among the different families of the human race.
DESTRUCTION AND RENEWAL OF EPIDERMIS.
The epidermis, like the epithelium, is constantly undergoing
destruction and renewal; the evidences of this are, however, more
obvious and striking in the case of the epidermis, than were those
adduced in proof of the destruction of the epithelium.
Thus the destruction of the epidermis is proved by a variety of facts:
By the gradual disappearance from the skin of indelible stains, such
as those produced by nitrate of silver or nitric acid.
280 THE SOLIDS.
By scraping the soles of the feet after immersion in warm water;
the white and powdery material which is obtained, often in large
quantities, examined with the microscope, will be found to consist of
epidermic scales.
By the use of the warm bath; floating on the surface of the water
will be observed more or . less of a thin and whitish scum ; this
consists of desquamated epidermis.
By rubbing the moist skin with a rough towel; a considerable
amount of epidermis, visible to the naked eye, will be removed.
The skin of new-born children is frequently observed to be
covered with a white and soap-like crust; this, examined with the
microscope, will be found to consist of epidermic scales mixed up
with sebaceous matter.
The last proof to be adduced of the desquamation of the epidermis
is one derived from disease; after inflammation of the skin, whether
that of erysipelas, scarlatina or measles, the epidermis peels off, a
new one being previously formed beneath the old.
Among many of the amphibia and reptiles, the casting of the
epidermis is a periodical occurrence; in man, on the contrary, it is
a constant and gradual process normally, although it is also occasion-
ally periodic from disease.
USES OF THE EPIDERMIS.
The principal uses of the epidermis are threefold.
The first and chief use is to serve as a protection to the more
delicate parts which lie immediately beneath it.
The second is to prevent the too rapid dissipation of the caloric of
the system.
The third use has reference to secretion. It is evident, however,
that the importance of the epidermis as a secreting organ is not con-
siderable, seeing that the external surfaces of the body do not require
to be kept moist, to the same extent as the internal." That the epider-
mis does not very actively administer to secretion might be inferred
from the* transparency of the fully-developed cells, the faintness of
the nuclei, and the paucity of the granules contained within them.
Epidermic cells are also capable of absorption, a fact which their
change of colour after long immersion in water testifies.
By far the best description of the anatomy of the epidermis which
has fallen under my notice is that contained in the admirable chapter
on the Anatomy and Physiology of the Skin attached to the second
edition of Mr. Wilson's work on the Diseases of the Skin.
EPIDERMIS. 281
EPIDERMIS.
[In the paper by Mr. Rainey, referred to in the Appendix, he divides the
epidermis into two layers, the superficial layer or cuticle, and the deep layer
or rete-mucosum of other authors. The deep layer rests on the basement
membrane covering the papillae, and fills up the grooves between them: this
layer is composed of nucleated cells, in different stages of development:
those below being very small, probably only cell nuclei, those in the centre
are most perfect, and those above approaching the condition of epidermic
scales.
The superficial layer, or cuticle, extends from a little beyond the apices
of the papillae to the surface, and consists of flattened cells, which have
become converted into scales. These scales are not affected by action of
acetic acid, or strong solution of potassa, while by these reagents, the
nucleated cells are entirely destroyed.
In the Appendix, already alluded to, the author has referred to the state-
ment made by Mr. Rainey, that no true duct from the sudoriparous glands
exists in either layer of the epidermis, the passage being a spiral one
through the epidermic cells and scales. ( Vide Plate LXXV1IL, figs. 1, 2.)
The lining of the sudoriparous duct, separated with the epidermis after
maceration, is the epithelial lining of the duct, and not the entire duct, as
stated by some writers.
The epidermis may be readily examined in thin vertical sections made
with the Valentin's knife, or sharp scalpel. The fresh skin will be found
best for this purpose, and those portions from the heel or palm of the hand
show the structure best: these maybe farther dissected with the needles
under the microscope and in water, and other sections may be treated with
acids and alkalies. In some instances, thin sections can be better made
when the skin has been hardened, and rendered more firm than in its
natural state.
For this purpose, a strong solution of carbonate of potassa, diluted nitric
acid, or sulphuric ether, may be used. When sufficiently thin sections can
be obtained without this process, the structure is more readily made out,
and with a good Valentin's knife, this is not usually difficult to do. By
continued maceration, the epidermis may be separated in layers ; this pro-
cess is necessary to exhibit well the deep layer or rete-mucosum.
When desired, sections of epidermis may be mounted in fluid for preser-
vation: but in this condition they will be of little service, unless to show the
spiral passages and external orifices of the sudoriparous ducts. The rete-
mucosum is also best preserved in fluid.]
282 THE SOLIDS.
ART. XI. THE NAILS.
The horny appendages of the feet and hands, the nails, do not
constitute a distinct structure or type of organization in themselves,
but are merely modifications of one which has already been described,
viz : the epidermis.
Nails, therefore, consist of cells similar to those of which the
epidermis is itself constituted, with the difference that they are harder,
drier, more firmly adherent to each other, and that in the majority
the nucleus is obliterated. (See Plate XXV.)
To display the cellular constitution of nails, some little nicety is
required; it may be shown, however, in the thin scrapings of any
fragment of nail submitted to the microscope, as also by soaking the
nail in a weak alkaline solution, and which, acting upon and dissolv-
ing the inter-cellular and uniting substance, sets free the cells.
The cellular structure of nails may also be shown, even without
previous preparation, by a careful examination of the root and under
surface of the nail, in which situations young and nucleated cells may
usually be detected.
The younger nail cells, like those of the epidermis in the coloured
races, contain pigmentary matter.
Nails, however, are not simply constituted of super-imposed and
adherent cells, but these are regularly disposed in layers or strata,
each of which probably indicates a period of growth.
These layers, marked by striae, may be clearly seen on any thin
section of nail, whether longitudinal or transverse; they do not appear
to follow any very definite course; usually in a longitudinal slice,
they run from above, downwards and forwards; sometimes they are
horizontal, but I have seen instances in which the striae were directed
obliquely backwards, in place of forwards. In the transverse section,
the striae are less strongly marked, and run usually moi'e horizontally.
(See Plate XXV.) Occasionally they are seen to pass in opposite
directions, and to decussate. I am disposed to think that the one set
of striae visible are rather apparent than real, and are produced by the
knife employed in making the section.
It is usually easy to distinguish the superior from the inferior edge
of a slice of nail; the former will generally appear quite smooth,
while the latter will be rough and uneven. (See Plate XXV.)
THE NAILS. 283
Such is a brief sketch of the structure of nails:* their form, posi-
tion, and mode of connexion, may next be considered.
Each nail may be said to be quadrilateral and convex from side to
side, as it is also very generally from before backwards ; the three
posterior margins are received into a groove formed by a duplicature
of the dermis and epidermis, the anterior margin alone being free.
The root and sides of the nail, the former consisting of about one-
fifth of its extent, are intimately attached to both surfaces of the
groove; the inferior aspect of the body of the nail is likewise firmly
adherent to the derm beneath it, except for a small distance at its
anterior part.
The nail, then, is attached to the dermis by its root, and by a
portion of its inferior surface; this attachment, however, is scarcely
to be considered as structural, since it consists of a mere adaptation
of the opposing surfaces of the dermis and nail. The surface of the
dermis upon which the nail rests, it is known, is not smooth, but is
raised into papillae ; to these the nail adapts itself, and in this way the
two become intimately united.
It is in this manner, also, that the longitudinal lines observed on
most nails are produced, and the appearance of which has induced
some observers to entertain the idea that they are of a fibrous, and
not a cellular constitution.
Nails are, to a considerable extent, hygroscopic, becoming by the
imbibition of fluid soft and yielding.
DEVELOPMENT OF NAILS.
Nails are developed somewhat differently from the epidermis, of
which we have stated that they are a modification; thus, they do not
increase by the equal development of new cells on the entire of their
under surfaces, but they grow from a point, from the base or root of
the nail.
The reality of this mode of development becomes evident from the
following considerations:
1st. That the younger nail cells are found principally at the root
of the nail.
2d. That if the relative situations of two spots or stains be
*The first exact description of the nail and of the disposition of the derm which
supports it was given by Albinus (Adnotal. Acad. lib. ii. 1755, p. 56), but Schwann
showed that the nail had a lamellated structure, and that the lamellaj are composed
of epidermic scales. (Mikroskopische Unlersuchungen, 1839, p. 90.)
284
THE SOLIDS.
observed, it will be seen that during the growth of the nail, they
preserve precisely the same relation with each other, only that they
gradually approach the end or free margin of the nail, which at
length they reach, and from which finally they are worn away. This
observation proves the absence of interstitial growth, and shows that
the nail increases in length by additions made to the root.
Although it is certain that the longitudinal growth of nail occurs
by the development of cells at the root, yet it is also evident that its
thickness is increased by the formation of new cells on its under
surface, where they may usually be detected with the microscope in
a partially developed state. This double development explains why
the nail is thinnest at the root, where only a single method of growth
prevails.
The junction of the root with the body of the nail is indicated by
a semi-circular line, and the former is not merely thinner than the
latter, but it is also softer and whiter; whiter in consequence of the
subjacent dermis containing in that situation fewer blood-vessels, and
its papillae being smaller.
From the pi-eceding account of the development of nails, it follows
that when these sustain any loss of substance on their upper surfaces,
this loss is never repaired, but remains without alteration until it
reaches the free margin of the nail.
Epithelium, epidermis, nails, and some other structures of the body,
never seem to attain to a stationary state; they are throughout the
wThole of life undergoing a process of development; this, in the case
of the nails of man, renders the interference of art necessary to
remove from time to time the redundant growth.
It is probable, however, that if the nails were not cut, but allowed
to grow at will, they would not exceed a certain length; among the
Chinese, who do not pare their nails, they are usually about two
inches long.
Nails doubtless sustain a loss of substance beyond that which they
experience from occasional cutting, as from friction and the des-
quamation of the cells from the inferior and anterior portion of each
nail, and which may be inferred to take place from the fact that the
matter which accumulates beneath the extremities of the nails is to a
great extent made up of epidermic or nail cells.
It has been estimated that the entire body of a nail, from the root
to its free margin, is developed in from two to three months.
The third month of intra-uterine life is the earliest period at which
THE NAILS. 285
the nails can be detected ; they then consist of nucleated cells, and
rather resemble soft epidermis than the hard and horny texture of
fully-developed nails.
A nail which has been once entirely destroyed is always regen-
erated in a very imperfect manner, it being usually seamy and
irregular in consequence of the disturbance and injury sustained by
the adjacent dermis, and the markings of which are impressed upon
the nail.
Nails are subject to deformity in certain chronic maladies of the
heart and lungs, especially in cyanosis and phthisis. It has been
suggested that this may depend upon the state of the circulation in
the vessels of the dermis.
The various modifications of nail met with throughout the animal
kingdom, the claws of birds and carnivora, the hoofs and horns of
ruminants, have essentially a similar structure to the nails of man.
The hoof of the horse and of some other animals is traversed from
above downwards by the spiral ducts of the sebaceous glands.
NAILS.
[The structure of nails is examined in thin sections and scrapings, placed
in the field of the microscope, and covered with a drop of water, or oil of
turpentine.
The secreting vessels of the nail, so well described by Mr- Rainey in his
paper quoted in the Appendix, can only be seen after injection, and the
removal of the nail. A foetal subject is well adapted for this injection. A
hand or foot of an adult may sometimes be so well filled as to exhibit these
vessels.
The sections or scrapings of the nail, may be preserved dry, in fluid, or
in balsam, the choice depending on the thickness of the specimen. The
injected matrix, &c, is best preserved in fluid; for this purpose, alcohol
and water, or Goadby's B-solution, may be employed,
See Appendix, page 541.
Plate LXXI. represents the different vessels as described by Mr. Rainey.]
THE SOLIDS
ART. XII. — PIGMENT CELLS.
Colouring matter is found in the animal organization in two
states, either diffused throughout the fluid contents of colourless cells,
as in fat cells generally, but especially in those of the iris of birds,
and as in the liver cells, and red blood discs, or it is limited to the
granules contained in certain peculiar cells, the parietes of which are
also colourless, which have received the name of pigment cells, and
which we are now about to describe.
Pigment cells have precisely the same structure as those of
epithelium and epidermis, the description of which has just been
brought to a conclusion; that is, they consist of cell wall, nucleus,
cavity, and granules; the only difference between the two is, that the
granules in the one case are coloured, and in the other colourless:
as may be inferred from their similarity of organization, a similar
mode of development prevails in both.*
All the varieties of colour of the eye and of the skin, observed
among the different members and families of the human race, depend
upon the number of pigment cells and the shade and intensity of the
colouring matter enclosed within the pigmentary granules; the deeper
the colour, the more abundant the pigment cells, and the greater the
depth of colouring contained in the granules; thus, of course, the
pigment cells scattered beneath the epidermis of the Ethiopian are
far more numerous than those found beneath that of the white race,
and the colouring; matter of the granules is doubtless also darker.
In the white, however, a greater or less number of pigment cells is.
almost invariably found in certain situations, as in the eye, on the
internal surface of the choroid, and the posterior aspect of the iris
and ciliary processes, also between the sclerotic and choroid; in the
skin at certain localities where it is placed beneath the dermis and
epidermis, as in the areola round the nipples, especially of women,
and about the perinaeum and genital organs.
In the black races, pigment cells follow a similar distribution in
* Mondini (Comment. Bonon, t. vii. 1791, p. 29,) was the first observer who made
accurate microscopic observations on the pigment of the eye. He stated that the
pigment is not simply mucus, but a true membrane formed of globules disposed in
quincunx. The son all but completed the work which the parent began : he found
that each globule is made up of little black points. Finally, Kieser (Be Anamorphosi
Oculi, 1804, p. 34,) described the pigmentary membrane as a cellular tissue containing
corpuscles.
PIGMENT CELLS. 2S7
the eye; but beneath the epidermis, as also under the nails, they
form a continuous stratum composed of super-imposed layers of cells.
There are yet other situations in which pigment cells have been
encountered : thus, Valentin* has signalized the occurrence of pig-
mentary ramifications in the cervical portion of the pia mater, to
which they impart a blackness perceptible to the unaided sight.
Again, Wharton Jonesf has described a thin but evident layer of
brown pigment in the membranous labyrinth of the ear of man. It
has been observed in other mammalia, in which it is still more
marked, in the same situation, by Scarpa, Comparetti, and Breschet. J
The brown spots, known by the name' of freckles, with which the
faces of most persons are more or less covered in summer, are due to
a development of pigment cells.
A development of pigmentary matter frequently takes place as the
consequence of disease; thus, it is of common occurrence to meet
with growths either entirely or in part composed of pigment cells, the
tumours, with the proper structure of which it usually thus inter-
mingled, being those of cancer or medullary fungus.
The nature of the pigment-like matter found in the lungs and
bronchial glands of aged persons and animals has been the subject of
much discussion ; nor has it been as yet decided whether it be true
pigment, or merely a deposition of carbon. Pearson§ maintained
the opinion that the colouring matter is the powder of carbon, since
neither chlorine nor the mineral acids act upon it.
In those remarkable lusus natures, Albinoes, there would appear to
be an absence of pigmentary granules in all parts of the body, even
in the eye: the pigment cells themselves are stated to exist, but to be
wanting in their characteristic coloured contents.
Pigment cells do not present the same size, form, and character
wherever they are encountered.
Thus, those of the choroid are adherent, large, flattened, polygonal,
mostly hexagonal, with clear nuclei and margins; occasionally, how-
ever, it happens that both nuclei and cell wall are obscured by the
number and disposition of the contained granules : the cells are mostly
of uniform size as well as shape, in consequence of which regularity
they form a very beautiful microscopic object; sometimes, however,
* Verlaufund Enden der Nerven, p. 43.
f Article Hearing in the Cyclopaedia of Anatomy and Physiology, t. ii. p. 529.
I Rtcherches sur VOrgane de VOiiie de V Homme, Paris, 1836, in 4to.
\ Philosophical Transactions, 1813, pi. ii. p. 159
^Sy THE SOLIDS.
one cell is observed to be larger than the rest, octagonal, and sur-
rounded by a number of cells of smaller size than ordinary, and
mostly pentagonal.
According to Henle,* the contained granules are situated in the
posterior part of each cell, while the nucleus is placed in its anterior
division ; it is this arrangement which allows of the nucleus being so
clearly seen ; in those cases, however, in which the nucleus is
obscured, acetic acid will frequently bring it into view; this, if con-
centrated, will dissolve the cell wall, set free the granules, and leave
the nucleus.
Schwann states that he has seen the pigmentary granules in the
cells of the choroid in active motion.
The cells of the choroid form by their adherence a membrane resem-
bling the most regular and beautiful mosaic pavement in miniature.
The pigment cells of the posterior face of the iris and ciliary
processes are smaller than those of the choroid, are for the most part
round, or approach that form, and so filled with the corpuscles that
the nucles and margin of the cell is not usually visible.
In the skin, the pigment cells are placed between the dermis and
epidermis ; they do not there form a layer of equal thickness, but
accumulate in the depressions left between the papilla?, forming many
super-imposed layers, while on these they are spread out in a single
thin layer, and are often much scattered. It is to this circumstance,
as well as the thickness of the epidermis, and the state of repletion of
the cells, that the varying shades of the colour of the skin of the
same individual depend. In the negro, the cells resemble much in
form those of the choroid, being either perfectly hexagonal, polygonal,
or irregularly rounded ; the nucleus can be well seen in those cells
which are less filled.
Among the white race, the pigment cells in those situations in
which they occur beneath the skin are fewer in number, smaller,
more rounded, and frequently resemble little masses of corpuscles
rather than distinct cells; nevertheless it is even here sometimes
possible to distinguish the nucleus and cell wall.
There exists between the internal face of the sclerotic and the
external of the choroid a fibrous tissue of a brown colour; this, when
these two coats of the eye are separated, remains attached in part to
the one, and in part to the other; that, however, which adheres to
the sclerotic has received a distinct name, and is called lamina fusca.
* Anat. Gen. vol. vi. p. 295.
PIGMENT CELLS. 289
Now, the colour of this layer is due to the presence, scattered among
the fihres, of pigment cells of a very peculiar form and construction ;
they are mostly very irregular in size and shape, are marked with a
clear central spot, which indicates the locality of the nucleus, and
from the margin of many of them proceed filamentous processes of
variable number and size, and the extreme points of which are mostly
colourless, and are not dissolved by acetic acid.
Pigment cells of analogous construction exist on the external surface
of the choroid, and also on the cervical portion of the pia mater.
Mixed up with perfect pigment cells a greater or less number of
pigment granules are always observed ; these are among the smallest
objects in nature, and, on account of their minuteness, it is in them
that molecular action in all its activity is best seen: they are not
spherical in form, but are flattened, so that they appear as discs, lines,
or points, according as the surface, side, or end presents itself to the
eye of the observer.
It is probable that it is by means of these granules that pigment
cells are multiplied.
Climate, and particular states of the system, as pregnancy, have
much effect in increasing the amount of pigmentary matter beneath
the skin; from the latter cause, the areolae around the nipples
frequently become of a deep chocolate colour. Of the influence of
the former, it is scarcely necessary to cite examples : it may be
remarked, however, that freckles are due to the development of pig-
ment cells, brought about by the action of the summer's sun.
This augmented development of pigment cells may be rationally
explained by the increased determination of blood to the dermis of
the breast from increased activity of function in that organ during
pregnancy, and to the general surface from the effect of the sun's heat.
It is questionable whether all the varieties of colour of the human
species have not originated in climateric causes, operating through
many ages.
It may also be questioned whether pigment cells are not susceptible
of being developed into those of the epidermis. If the epidermis of
a negro, raised from the surface by means of a vesicatory, be exam-
ined with the microscope, it will be noticed that the most external cells
contain a considerable amount of colouring matter, which, as this
resides in solid granules and not in a fluid, it is difficult to suppose
had entered the cells by endosmosis.
Pigment cells are capable of regeneration, in a part in which they
19
290 THE SOLIDS.
have been destroyed: it is necessary, however, that the subjacent
dermis be not too deeply injured ; the cicatrices remain for a consid-
erable time nevertheless without colour.
The skin of the children of negro women does not acquire its full
depth of colouring for some days after birth.
Pigment cells are developed at a very early period of intra-uterine
life. The uses of pigment in the skin are not well understood; that
in the eye is doubtless of importance in the discharge of the functions
of that organ: it is known that the Albinoes, in whom it is either
absent or exists but in small quantities, are incapable of supporting a
strong light.
Pigment cells of particular forms occur among some of the lower
animals. Those of the internal surface of the choroid of fishes and
birds, situated in front of the ordinary coloured cells, have the form
either of short sticks or clubs. The argentine pigment of the iris
and peritoneum of fishes is composed of elongated corpuscles. The
pigment cells placed beneath the epidermis of the frog are for the
most part stellate.
PIGMENT CELLS.
[Pigment cells are most readily studied on being detached from the
choroid coat of the eye, by means of a fine needle. On rupturing the cells,
the pigmentary matter escapes ; and with a high power of the microscope,
numerous black or brown molecules will be observed. These molecules
measure from TTin to g jio o of an incn in diameter.
These cells may also be studied with advantage in the cuticle of the
negro, which may be detached after slight maceration, and also in the skin
of the frog.
The pigment cells in the frog, will be found to consist of long, irregular,
jagged processes.
Cells containing pigmentary matter are well preserved in the flat cell
with fluid.]
HAIR. 291
ART. XIII. — HAIR.
We now come to the description of another epidermic modifica-
tion, viz: hairs; these, however, are much more complex in their
structure than any which have been hitherto described, and are less
obviously derived from the epidermis.
As in the case of most of the solids described in this work, we shall
first discuss the different particulars relating to form and size, and next
proceed to the description of structure.
FORM OF HAIRS.
Hairs consist of two parts, a root and a stem : in speaking of the
form of hairs, reference is made to the latter. Hairs, then, are elon-
gated, and more or less cylindrical developments of the epidermis.
They depart, however, in most cases, from the character of a true
cylinder in two respects; first, they are not perfectly spherical, but
are seen to be, when viewed transversely, either oval, flattened, or
reniform (see Plate XXIX.) ; and secondly, they are not of equal
diameter throughout, being thickest at about the junction of the lower
and middle thirds of the stem, of smaller diameter from this part down-
wards towards the root, and still more reduced in size as the free
extremity is approached, and which, in a hair which has not been
recently cut, terminates in a point, the diameter of which is frequently
several times less than that of the more central parts of the shaft.
(See Plate XXIX.)
This form is best seen in hairs of medium length, as those of the
whiskers, eyebrows, axillae, and pubis, in which also the flattened and
oval shapes are principally detected.
The hairs which approach most closely the cylindrical, are those of
the scalp.
Henle* makes the interesting statement, that the curling of hair
depends upon its form, and that the flatter the hair, the more it curls,
the flat sides being directed exactly towards the curve described.
From this it follows, that the hair of negroes would exhibit in a very
marked manner this flattened form.
* Anat. Gen., vol. vi. p. 314.
292 THE SOLIDS.
SIZE OF HAIRS.
Hairs differ remarkably in size, both as regards length and breadth:
they differ not merely in different individuals, in different localities
'in the same person, but also in any one given situation, as the scalp
or pubis.
The hairs of the scalp are the longest; those of the scalp of women
are many times longer than those of the same part in man, and accord-
ing to the measurements of Mr. Wilson, they are also thicker. Next in
length come the hairs of the chin of man. Among women, instances
have been known of the hair extending from the scalp to below the
feet, and the beard of man not unfrequently reaches to the waist.
The shortest and smallest hairs are those covering the general sur-
face of the body, and which are reduced to mere down (lanugo).
The thickest hairs of the body are those of the whiskers, chin, pubis,
and axilla?; the finest, those distributed over the general surface; the
hairs of the scalp are of intermediate diameter.
The hairs of children are finer than those of adults, and those of
the head of men than those of women.
It cannot be doubted but that frequent cutting and shaving of the
hair tends to increase its thickness.
STRUCTURE OF HAIR.
Each hair admits of division into two parts, the root and stem;
and each of these, again, allows of still further sub-division : thus, the
root consists of the prolongation of the hair proper, or stem, termi-
nating in an expanded portion, which has been termed the bulb, and
of a double sheath; the stem also is divisible into cortex, medulla, and
intervening fibrous portion, which constitutes the chief bulk of the
hair. (See Plates XXVIII. and XXIX.)
These divisions of the root and stem of hairs suggests its comparison
to a tree, the stem of which also resolves itself into cortex, medulla,
and intervening woody or fibrous substance. The comparison is also
heightened by the similar relation in which both stand to the parts
around them, viz : the soil in the case of the tree, and the dermis in
that of the hair.
ROOT OF HAIR.
We will first describe the root, because it is the source from which
the hair is developed: this, as already noticed, consists of two parts,
the sheath and the bulb.
HAIR. 293
The Bulb. — The bulb is the expanded and basal portion of the stem
of each hair : it is usually two or three times the diameter of the hair
itself, and is sometimes excavated below : it is constituted of granular
cells, which are either circular, angular, or elongated in form ; the
spherical cells, form the extremity of the bulb, the polygonal ones its
surface, and the elongated cells are placed above the spherical ones,
of which they are modifications, and beneath the angular cells of the
surface of the bulb. Acetic acid will be found useful in displaying
the cellular structure of the bulb.
In healthy hairs this bulbous portion of the stem is always coloured,
which is not the case with gray hairs. (See Plate XXVIII.)
The part of the stem of the hair immediately above the bulb, and-
included within its sheath, exhibits the structure of the body of the
stem itself, being divisible into scaly cortex, fibrous intervening sub-
stance, and granular medulla.*
Sheath. — The bulb and lower portion of the stem of the hair is
included in a sheath consisting of two distinct layers, an outer and an
inner. (See Plate XXVIII. fig. 1.)
The outer layer is an inversion of the epidermis : it first merely
encircles the portion of the stem of the hair beneath the level of the
epidermis : it next surrounds the inner layer of the sheath, to which it
soon becomes intimately adherent; finally, it forms a cul-de-sac around
the bulb of the hair.
The fact of the inverted sheath of the epidermis forming a pouch
around the bulb of the hair, may be inferred from the circumstance,
that when the epidermis peels off as the result of decomposition, the
hairs usually come away entire with it ; its continuation, moreover,
around the bulb may be shown in transverse sections of the skin of
the axillae and whiskers, in which the hairs penetrate into the sub-
cutaneous fatty substance. (See Plate XXVIII. fig. 1.)
This outer layer is colourless, is possessed of considerable thickness,
and is evidently made up of granular cells similar to young epider-
mic cells.
In most hairs, whether coloured or uncoloured, which have been
forcibly removed from the skin, this outer layer is usually torn across,
the rupture occurring almost invariably at a little distance from the
bulb of the hair: the root of the hair, then, below this breach of con-
tinuity, consists only of the inner layer of the sheath and of the stem
of the hair ; and at this situation the root, to the naked eye, appears
* See Appendix, p. 549.
294 THE SOLIDS.
contracted: this is, however, but an appearance, the result of the
absence of the outer layer, and of the expansion of the stem into the
bulb. (See Plate XXVIII. fig. 2.)
The inner layer of the sheath is an eversion or revolution of the
epidermis, and is an offset or continuation of the outer layer, com-
mencing at the lower part of the bulb : it is colourless, possessed of
considerable thickness, its diameter being about one-third of that of
the stem of the hair in its thickest part : it tears readily in the longi-
tudinal direction with a somewhat uneven fracture ; and hence may-
be inferred to be of a fibrous constitution, as may be shown to be the
case : its inner surface is marked with reticulated lines, the impressions
of the cortical scales of the shaft of the hair.
This inner layer is not of equal diameter throughout, but tapers
gradually from below upwards: it is well defined both internally and
externally, except where it comes in contact with the bulb internally,
with which its inner edge or surface becomes incorporated; above, it
terminates in a thin border at a little distance below the level of the
skin. (See Plate XXVIII. fig. 1.)
The outer layer, although adherent to the inner at its lower part,
does not become incorporated with it : the latter, except at the point
indicated, preserves every where its independence and individuality.
The two layers, it will thus be seen, might with much convenience
have been described, as two distinct sheaths, an inner and an outer:
to do so, would be, however, to lose sight in some measure of the
similar origin and nature of the two.
In the fact, however, of the inner sheath exhibiting a fibrous struc-
ture, and of its incorporation with the bulb, it would appear to have
more structural affinity with the fibrous portion of the stem of the
hair itself than with the outer layer or cellular sheath.
This inner layer might be appropriately termed the "modelling
sheath," since it doubtless regulates the form and dimensions of the
shaft of the hair, the substance of which when first developed is soft
and plastic. Henle describes the inner layer as fenestrated : this
structure I have never seen exhibited.
Shaft of the Hair.
The stem or shaft of the hair is divisible, as already observed, into
cortical, medullary, and fibrous portions.
Cortex. — The cortical part of the hair consists of a layer of scales,
imbricated upon each other after the manner of tiles upon the roof
HAIR. 295
of a house. (See Plate XXIX.) These scales are best seen in the
larger hairs of the whiskers and pubis, and in the small downy hairs;
they are smaller than the ordinary cells of epidermis, and are rarely
seen to be nucleated. Maceration of the hair in sulphuric acid
causes them to fall off, and in this way their size, form, and structure,
may be satisfactorily studied.
The scales are absent from the points of the finer hairs. In con-
sequence of their imbrication upon each other, their little thickness,
and of the double contour presented by their free edges, they
frequently convey the appearance rather of anastomosing fibres
running round the hair than of distinct scales.
A hair rolled between the fingers always advances in a given
direction, viz: towards the apex: this results in part from the taper-
ing form of the hair, and partly from the more or less spiral disposition
of the scales.
Fibrous Layer. — The fibrous portion of the stem of the hair
constitutes its chief substance and bulk, forming two-thirds of the
entire diameter, one-third on each side of the medulla. In hairs which
are not too dark, the constituent fibres may be seen in situ: they are
most palpably brought into view either by scraping the hair with a
knife or by crushing it after masceration in sulphuric acid : they are
also best seen in the larger hairs and near the centre of the shaft.
Henle describes the fibres as flat, with uneven edges, and is in
doubt as to whether they are branched or not. To my observation
they appear much smaller than they are stated to be by Henle, and
are spherical and simple. (See Plate XXIX.)
These fibres have a cellular origin, and are formed by the elongation
of the inner cells of the bulb, in which their gradual extension into
perfect fibres may be traced.
• They are stated by most observers not to extend to the extreme
point of the hair; and the same statement is likewise made in refer-
ence to the medullary canal and cortical scales. Of what, then, it
may be fairly asked, is the point of the hair constituted, since every
structure entering into the formation of the shaft is denied to it?
The assertion that the fibres do not extend to and form the apex of
the hair is evidently erroneous. In the examination of the points
of a number of hairs which have not been recently cut, fibres, often
separated from each other and loose, will frequently be detected.
(See Plate XXIX.)
The whole of the fibres of the stem, however, do not extend its
296 THE SOLIDS.
entire length, the majority terminating long before the extremity is
attained; and it is to this fact that the attenuated form of the hair
is attributable. In some hairs the fibres are seen to terminate at
regular distances, their points describing transverse lines on the stem
of the hair.
The splitting, of such common occurrence in hairs which are
allowed to attain an excessive length, is due to a separation of the
fibres from each other.
The fibrous portion in young and healthy hairs is coloured.
Medullary Canal and Medulla. — In most hairs which are not of
too deep a colour a medullary canal may be detected running up the
centre. This commences in the upper portion of the bulb, runs
along the shaft, but ceases as it approaches the apex: its diameter
varies with that of the hair itself, but usually bears the proportion of
a third of its thickness. (See Plates XXVIII. and XXIX.)
Henle is uncertain whether this canal is lined by a distinct mem-
brane or not, but inclines to the opinion that it is so.
The medulla or contents of this canal exhibit a granular appear-
ance, and are made up of pigment granules, a few perfect pigmentary
cells, and particles of coloured oil ; it is therefore in the medulla that
the greatest amount of colouring matter of the hair is situated. (See
Plate XXVIII. fig. 1.)
At the very commencement in the bulb of the hair, the medulla
has distinctly a cellular origin.
In young and healthy hairs it is also continuous throughout the
entire extent of the medullary canal; in old and discoloured hairs,
on the contrary, its continuity is frequently interrupted by distinct
intervals, and it only partially fills the cavity of the canal .even
where it is present.
The medullary canal and medulla is best seen in the larger hairs,
which are not of too deep a colour, and in gray hairs: in the fine
and downy hairs of the general surface of the body, the canal and
its contents, as a necessary consequence, are almost entirely absent.
In some rare instances, two medullary canals have been observed
in the same hair. In the sable, the medulla has a distinctly cellular
structure throughout.*
* The first accurate observations on hair were made by Hook, Micographia, 1667,
Obs. 32. tab. v. fig. 2., and Leeuwenhoek, Opera, t- iv. p. 46.
HAIR. 297
FOLLICLE OF THE HAIR.
Each hair is implanted in a distinct depression in the dermis, the
base of which especially is freely supplied with nutrient vessels: this
depression is also lined by an invagination of the epidermis, and
which becomes ultimately the outer layer of the sheath of the root
of the hair as already described. (See Plate XXVI. fig. 3.)
Between this layer, however, and the shaft of the hair for a short
distance before it rises above the level of the skin, a space or cavity
is left; into this space the canals of one or more sebacious ducts
generally open, and in it also entozoa frequently develope themselves.
It sometimes happens that two or more hairs are contained in the
same follicle (see Plate XXVI. fig. 3) : in these cases, however, each
hair has a distinct modelling sheath. In some animals, the location
of a number of hairs in one sheath is the ordinary mode of arrange-
ment; in the pig, for example, the hairs are usually thus associated in
three's, as also occasionally in man.
The hair follicle or crypt is best seen by examining thin vertical
slices of the skin.
The length of the hair follicle and the consequent depth of implant-
ation of the hair varies, but is often equal to the twelfth or sixteenth
of an inch ; the hairs of the head, of the whiskers, of the pubis, and
of the axillae, penetrate into the sub-cutaneous cellular tissue; those of
the eyelids and ears, to the subjacent cartilages : the roots of hairs in
genera], however, do not penetrate beyond one-half the depth of the
corium, in the substance of which they are buried.
It is usually stated that the bottom of the follicle is occupied by a
papilla furnished with blood-vessels and nerves, on which the bulb of
the hair immediately rests ; and that it is owing to this papilla that
the base of the bulb, when removed, exhibits a concavity. This
description, in the case of tactile hairs, may be correct, but is surely
not so when applied to hairs in general. Each hair does indeed rest
upon a papilla, but it is one which is destitute of blood-vessels and
nerves, and which is cut off from all direct vascular communication
by the cul-de-sac formed by the outer lamina of the sheath. This
papilla may be described as a compound cellular vesicle, and is
probably the true germ of the hair; it is on it that the bulb of the
hair is situated, and which occasions the depression which this
generally displays when it has been forcibly extracted. This germ
is best seen in gray and light-coloured hairs.
298 THE SOLIDS
GROWTH OF HAIR.
The growth of hair takes place at the root, and is the effect of the
development of new cells, which is continually in progress in the bulb,
and which afterwards become modified into those of the scaly cortex
and fibrous stem ; these new cells, coming behind the older ones, contin-
ually press them forwards, and thus occasion the elongation of the hair.
But the elongation of each hair takes place in a manner very differ-
ent from that just mentioned, not from the development of new cells,
but by the gradual elongation and extension of the cells already
formed after they have quitted the bulb, and when they come to form
the shaft of the hair. This mode of elongation — it can scarcely be
called development — is proved by the gradual tapering of the hair
which takes place after the point has been removed: of the truth of
this fact, not the slightest doubt can be entertained.
At the period of puberty, a growth of hair takes place in certain
situations in which previously it was not apparent, as on the chin,
cheeks, in the axillae, and on the pubis, abdomen, and chest; this
development is an effect of the great functional activity which exists
at that period, and which is the occasion of the increased and rapid
growth of the several constituents of the body which then takes place.
The earliest periods at which the rudiments of hairs in the human
fcetus have been observed is from the third to the fourth month : the
hair follicle is formed in the first place, next the bulb, and then the
sheath and stem of the hair, which, in the early period of its develop-
ment, is curved upon itself.
Hairs are occasionally developed in certain peculiar situations, as
on the mucous membrane of the conjunctiva, the intestines, and gall-
bladder, in the ovaries, and in steatomatous and encysted tumours.
Hairs may be transplanted, and, it is said, will grow after such
transplantation in consequence of the adhesions and organic connex-
ion established between them and the adjacent tissues — a fact of
which practical advantage might be taken if correct.
When a hair has obtained the full term of its development, accord-
ing to the researches of Eble, it becomes contracted just above the
bulb : this change probably announces its death and approaching fall.
REGENERATION OF HAIRS.
Hairs are peculiarly susceptible of being affected by the condition
of the health, even more so than the epidermis. If this be vigorous,
HAIR. 299
as a rule to which there are many exceptions, it will be found that
the hairs themselves are thick, and firmly set in the skin: if, on the
contrary, the powers of the system be debilitated from any cause, the
hairs will either fall off spontaneously, or a very slight degree of force
will serve to dislodge them from their connexions.
If the bases of those hairs which fall out of themselves be examined,
or which are removed by combing and brushing, it will be seen that
the bulb alone has come away, the entire sheath and germ remaining
behind. In such cases, the hair is doubtless regenerated, and after
its regeneration, is usually stronger than it was previously. (See Plate
XXIX.)
It has not yet been ascertained by positive experiment whether the
hair is capable of reformation in those instances in which both bulb
and sheath have been removed: it is most probable, however, that
where they have been entirely abstracted, no renewal of the hair
could ensue.
It is possible that in some cases the apparent regeneration of the
hair arises, not from the development of new hairs in the primitive
sheaths and upon the old germs, but from the formation of new hair
follicles and germs : of this, however, no proof has as yet been given.
That a regeneration of new shafts of hair is continually in progress,
whether from new germs or the older ones is not known, is proved by
the detection of small and pointed hairs just emerging from the skin
in the scalp of even old persons.
NUTRITION OF HAIR.
Hairs are nourished in the same way as the epidermis itself; that
is, they do not receive into their own structure either blood-vessels or
nerves, but derive their nutriment from vessels which are so distrib-
uted as to come into close contact with the tissues to be nourished.
This indirect reception of the nutrient plasma explains the very
great susceptibility of the epidermis and its several modifications to
be influenced by causes affecting the general health, and in conse-
quence the circulation and the qualities of the circulating fluid.
The epidermic tissues being placed in situations the most remote
from the centre of the circulation, are endowed with but a feeble
degree of vitality, and which is readily destroyed by causes affecting
the amount and nature of the circulating fluid received by them.
The nutrient vessels and sentient nerves of each hair are distributed
around and outside the sheath, and not in a raised papilla, as generally
300 THE SOLIDS.
described, although this may really be the case in the large hairs of
the whiskers of some animals, as, for example, the tactile hairs of the
seal, &c. The fact of the hair usually penetrating below the level of
the true skin and into the sub-cutaneous fatty tissue seems to dis-
prove the notion of a distinct and vascular papilla.
DISTRIBUTION OF HAIRS.
Hairs are distributed over the entire surface of the body, with the
exception of the palms of the hands, soles of the feet, and last phalanx
of the toes and fingers : there are, however, situations in which they
are developed in increased quantities, as on the integument of the
scalp, on that of the eyebrows, on the margins of the ciliary cartil-
ages, and after the period of puberty, on the chin, cheeks, axilla, pubis,
abdomen, chest, and at the entrance of the nares and ears.
The number of hairs found in these several situations differs very
considerably in different individuals, according to age and condition
of health.
Individuals of the male sex also are generally more hairy than
females, in whom also no development of hairs takes place on the chin,
cheeks, chest, and abdomen.
Of the number of hairs which exist on the entire surface of the
body, some idea may be formed from the measurements of Withof.
The quarter of a square inch furnished 293 hairs at the synciput, at
the chin 39, at the pubis 34, on the fore-arm 23, at the external border
of the back of the hand 19, and on the anterior surface of the thigh
13. Upon the same extent of surface, Withof counted 147 black
hairs, 162 brown, and 182 flaxen.
Hairs of great length and strength are often developed in consider-
able quantities in different parts of the body, in moles and naevi.
DffiECTION OF HAIR.
The hair follicles are not placed vertically in the skin, but obliquely,
and the hairs which issue from them consequently themselves run in
the same oblique direction. (See Plate XXVI. jig. 3.)
The apertures of most of the follicles look downwards, and hence
we find in most cases that the points of the hairs, when fully devel-
oped, are similarly directed.
In addition, however, to this general arrangement and distribution,
it will be seen that in early life the hair follicles are disposed in lines,
the apex of one follicle nearly touching the base of the next: the lines
HAIR. 301
thus described are not straight, but are more or less curved, and
divergent or convergent, after the manner of the lines upon the case
of an engine-turned watch: the hairs which issue from the follicles
thus take particular and determinate sweeps, which it is unnecessary
to describe in detail.
It occasionally happens, from some cause or other, that the hair
follicles are implanted in a manner the reverse of that which should
obtain: this is especially seen in those of the scalp of children, in
whom frequently certain tufts of hair grow up, and incline in a
direction opposed to that of the contiguous hair. This mal-disposition
of the hair is the source of much trouble and annoyance to anxious
nurses and mothers, who spend much time in endeavouring to bring
the refractory lock into order.
In this endeavour there can be no question but that it is possible to
succeed, as is proved by the very different arrangement which the
hair of the head is made to follow in accordance with the manner in
which it is dressed.
ERECTION OF HAIR.
Man, to a certain extent, and many animals in a considerable degree,
possess the power of erecting the hairs. This power in man is limited
to the hairs of the head, in many animals it is much more general.
Most persons, on sudden exposure to cold, and on experiencing of
any emotion of fear or horror, feel a creeping sensation pass over the
head: this sensation is accompanied by a certain degree of erection
of the hair, but not indeed to such an extent as to cause it " to stand
on end." JMow, this erection is the result of the distribution of fibres
of elastic and contractile tissue throughout the substance of the
corium, and which, interlacing among the hair follicles, occasion the
erection of the hairs themselves.
The distribution of these fibres, and their connexion with the bases
of the hairs, are well seen in the skin of the hog.
COLOUR OF HAIR.
The colour of the hair depends upon the same cause as that of the
skin and eye, and is due to the presence of pigment granules and cells ;
these are contained principally in the medullary canal, but are also
interspersed between the fibres of the stem ; they first become manifest
in the upper portion of the bulb of the hair.
The depth of the colour of the hair very generally bears a relation
302 THE SOLIDS.
to the development of pigmentary matter in other parts of the system,
as in the eye and beneath the skin. To this rule, however, some
remarkable exceptions are occasionally encountered.
The colour of the lighter hairs, as the red and flaxen, would appear
to depend less upon the number and depth of colouring of the pigment
cells and granules, than upon the presence of minute globules of a
coloured oil.
In the hair of Albinoes but little colouring matter is present; and in
gray hairs, also, the colour has deserted the pigment cells and granules.
Hair is decolorized by long contact with chlorine.
It is generally stated as an undoubted fact, that the hair may turn
white, or become colourless, under the influence of strong and depress-
ing mental emotions, in the course of a single night. This singular
change, if it does ever occur in the short space of time referred to,
can only be the result of the transmission of a fluid possessing strong
bleaching properties along the entire length of the hair, and which is
secreted in certain peculiar states of the mind.
GRAY HAIR.
If a gray hair be contrasted with an unaltered one from the head
of the same person, the following differences will be noticed between
the two. The gray or white hair will be observed to be almost
colourless, the bulb and fibrous portion will be destitute of colour, the
medulla alone retaining a slight degree of coloration: this, however,
is collapsed, and in place of being continuous throughout its length,
will be seen to be interrupted at intervals. (See Plate XXVIII. fig. 2.)
The unaltered hair, on the contrary, is distinguished by characters
the reverse of those exhibited by the gray hair; thus, the buib, stem
and medulla are all deeply coloured, and the latter fills the entire
cavitv of the medullary canal, and is continuous throughout. (See
Plate XXVIII. ^.1.)
Gray hair retains a considerable degree of vitality, as is proved by
its growth continuing for many years after its loss of colour.
PROPERTIES OF HAIR.
Hairs are remarkable for their strength, their elasticity, durability,
and for the difficulty with which they undergo the process of decom-
position: their strength results probably from their fibrous constitution;
in their elasticity and durability, they partake of the character of all
horny structures.
HAIR. 303
The strength of hair is proved by the fact that a single hair will
bear a weight of 1150 grains.
Its elasticity is shown by the readiness with which each hair, when
extended, returns to its original size and shape, as well as by the fact
that the numerous hairs forming a curl or lock will recover their
ordinary form and disposition after extension.
Its durability is shown by the persistence of hairs throughout many
years of life.
Lastly, its indestructibility is proved by the occurrence of hairs in
the tombs of persons buried for ages.
A hair, however, which has been very forcibly extended, will not
return to quite its original length, but will remain a certain degree
longer than it was previous to the extension. A hair may be
extended a third of its length without breaking; elongated a fifth, it
remains a seventeenth longer than it was before ; it continues a tenth
longer after having been extended a fourth, and a sixth only after
having been drawn out as much as possible.
Hairs, when they are dry, become electrical by rubbing, and emit
sparks: this is well known with respect to the coat of the cat, and
Eble has observed the same thing to occur in man.
Hairs are also eminently hygroscopic, and imbibe moisture from
the air and from the skin, in consequence of which they lose their
set or curl, and become flaccid and straight.
Nitrate of silver blackens the hair, a sulphuret of silver being
formed, and it is of this ingredient that the majority of hair dyes are
chiefly constituted. The concentrated mineral acids, especially the
nitric, dissolve the hair, as does also caustic potash.
When heated, hairs take fire, and burn with a fuliginous flame,
emitting the odour of bone, and leaving a residue of carbon. To
dry distillation, they yield a quarter of their weight of carbon, which
is difficult to incinerate, the products being empyreumatic oil, water
charged with ammonia, and combustible gases, which comprise sul-
phureted hydrogen. The ashes contain oxide of iron, traces of oxide
of manganese and silica, and of sulphate, phosphate, and carbonate of
lime.
THE HAIRS OF DIFFERENT ANIMALS.
The precise structure of the hairs of different animals varies con-
siderably : those of the mammalia resemble the hairs of man, or differ
only in the degree of their development, as the whiskers of the
carnivora and rodents, and manes and tails of horses, the bristles of
304 THE SOLID.
pigs, &c. : it is in these largely developed hairs that the structure can
be best determined : thus, in the majority of them it is stated to be
easy to detect the vessels and nerves of the papillae on which the
bulb rests, and which penetrate into it: nerves have been detected
by Eble in the cat,* by Rapp in the seal, porcupine, and many other
animals, f and by Gerber in the pig. J
In the hairs of the musk-deer, there seems to be no separation
of parts into scaly cortex, fibres and medulla, the entire hair being
uniformly cellular.
In that of the sable, the fibrous portion is absent, and there is only
scaly cortex and cellular medulla.
In the hairs of most rodents, the medulla is divided by dissepiments,
and in other animals, as the sable, it is composed of large and dis-
tinct cells.
The hairs of the mouse, bat, and martin, are branched or knotted.
In the spines of the porcupine and hedge-hog, the inner bark pene-
trates in longitudinal bands into the cavity of the medullary canal,
and thus divides the medulla itself into incomplete segments ; the
transverse view of such spines represent a starred or rayed figure.
In birds, hairs are replaced by feathers, which are to be regarded
as modified hairs.
THE USES OF HAIR.
The uses of hair are manifold.
In certain situations, as on the head, it is to be regarded as an
ornament.
In other localities, as on the cheeks and chin, it imparts character
and expression to the face.
In others again, as on the pubis and about the genital organs, it
serves the purpose of concealment.
The general use of hair, wherever encountered, it being a non-
conductor of caloric, is to preserve the warmth of the system.
Those situated at the entrance of the nares and meatus auditorius
externus, are placed there to prevent the entrance of foreign bodies,
insects, &c.
It is difficult to assign any use to the hairs of the axillae.
It is very probable that hairs have other uses, and that they exert
some influence in regulating the electric condition of the body.
* Von den Haaren, t. 11. p. 19. f Verrichtangen desfreuften Nervenpaares, p. 13.
J Allgemeine Anatomie, p. 79.
HAIK. 305
HAIR.
[Plate LXX., fig. 4, represents transverse sections of the human hair.
Transverse sections of the hair, sufficiently thin to show the cellular
structure, are somewhat difficult to make. When an instrument can be
obtained, such as is used for making thin sections of wood, they can be
prepared by taking a number of hairs, and gluing them together by means
of some adhesive material, so as to form a solid mass. This bundle is then
placed in the machine, properly wedged, and the transverse sections readily
made.
Another method, is to puncture a cork with a fine needle, and insert or
drive hairs in it ; when a sufficient number of hairs have been thus intro-
duced, thin sections of the cork may be made with a sharp scalpel or razor.
In these sections will be found some of the hairs cut transversely, and suffi-
ciently thin to show their structure.
Sections of the beard may be obtained by repeating the operation of
shaving a couple of hours after the beard was first cut ; on the razor will be
found minute points of hair. Some of these, when separated and spread out
with the needle, will exhibit transverse, others longitudinal sections.
When these are sufficiently thin to show their structure, they should be
mounted dry ; but if too thick to show well in this condition, they may be
rendered more transparent by being mounted in balsam.
The hairs of different animals present great varieties of structure, and
their study will be found replete with interest.]
20
306 THE SOLIDS,
ART. XIV. — CARTILAGES.
Cartilages are among the most solid structures entering into the
constitution of the animal organization; they are, however, not less
remarkable for their elasticity and flexibility than for their solidity.
The essential element of the several fluids and solids hitherto
described in the course of this work, we have seen to be cells: this
cellular composition is exhibited in a high degree by cartilages.
The texture and colour of the cartilaginous tissue varies consider-
ably : it presents either a white or bluish-white semi-transparent and
homogeneous appearance, or it is yellow, and exhibits a fibrous texture.
These differences of texture and of colour indicate a difference of
structure, upon which a division of cartilages into the true and fibro-
cartilages has been based.
TRUE CARTILAGES.
True cartilages consist of cells, contained in cavities, which are
themselves formed in a solid and hyaline inter-cellular substance.
They comprise all those cartilages which cover the articular extre-
mities of the bones (that of the glenoid fossa and of the head of the
inferior maxilla alone excepted), the cartilages of the entire respiratory
apparatus (with the exception of the epiglottis and the cuneiform car-
tilages), those cartilages which are to a considerable extent free and
independent, and which have been denominated figured cartilages, as
those of the ribs, the ensiform cartilage ; the trochlea of the eye, the
nasal cartilages, and the Corpuscula triticea in the lateral hyo-thyroid
ligaments. (See Plate XXX. figs. 1 and 2.)
The true cartilages are distinguished from the fibro-cartilages by
their bluish and transparent aspect.
Structure of True Cartilages.
True cartilages consist, as already mentioned, of hyaline matrix,
cavities, and cells; each of these constituents will be described in
succession.
Hyaline Matrix. — The inter-cellular substance, or hyaline matrix,
although it does not usually present any distinct traces of organization,
yet contains, scattered through it, numerous granules of different sizes,
and many of which are to be regarded as the cytoblasts from which
new cells are continually being developed.
CARTILAGES. 307
The amount of this inter-cellular substance varies in different car-
tilages, and is greater in fully-developed than in very young cartilage.
Cavities. — The cavities of true cartilages vary both in size and form;
in shape they are irregular, although for the most part elongated.
They are, in most cases, to be regarded as simple excavations or
fossae in the hyaline matrix; in others, however, it would appear from
the observations of Henle,* Bruns,f and Schwann, J that they are
lined by a distinct membrane, and which is indicated by a double
contour, by the difficulty experienced in setting free the contained
cells, and by the fact that, by boiling, the inter-cellular substance is
dissolved, while the cavities remain as distinct corpuscles.
Such cavities would stand in the relation of parent cells to those
which they include.
Cells. — The cells of cartilages are very different from those occur-
ring elsewhere in the animal organization; they are distinct in their
form and in the character of their contents.
Cartilage cells, like the cavities in which they are enclosed, are
irregular in size and shape; they are, however, generally elongated,
sometimes flattened and compressed; at others, they are perfectly
spherical : these several shapes depend upon the degree of pressure to
which the cells are subject, and which is greatest at the free margins
of the cartilages where the compressed form occurs, and least in the
centre where the spherical cells are chiefly encountered. Each cell
contains a nucleus, which is either smooth or granular; it includes
also very generally one or more shining and globular bodies of an
oleaginous or fatty nature, and which, in many cases, are to be
regarded as transformed nuclei.
The cells usually lie as it were scattered irregularly throughout the
inter-cellular substance ; in some cases, however, they are arranged in
definite order; thus, in the condensed margin of all the true cartilages
the cells are compressed, and lie with their long axes disposed parallel
to the surface. (See Plate XXX. fig. 1.) Again, in the ribs, they
radiate in straight lines from the centre towards the circumference:
this disposition of them accounts for the fibrous fracture which they
exhibit when broken across, as also for the fact of their being divis-
ible into thin transverse layers. The linear arrangement of the cells
in the fully-developed cartilages of the ribs is very frequently not
perceptible.
In very thin cartilaginous laminae, as those forming the alae of the
* Anal. Gen., vol. vii. p. 364. -f Allg. Anat., p. 215. \ Mikrosk. Untersuch
308 THE SOLIDS.
nose, the difference in the form of the central and peripheral cells
does not exist, the entire inter-cellular substance being filled with
small and rounded cells.
The cells usually occur singly in the hyaline matrix; they are,
however, frequently encountered in groups of two, three, or four cells,
each of which is distinct, and describes a more or less regular seg-
ment of a circle: this disposition of the cells is connected with their
mode of multiplication, as will be seen hereafter.
Again, groups of secondary cells sometimes occur, especially in the
inter-vertebral fibro-cartilages, included in the membrane of the pri-
mary or parent cell. (See Plate XXXI.)
Moreover, Henle* has noticed a peculiar arrangement of the cells
of the cartilages which cover the articulating surfaces of the larger
bones. On the free surface, the cells are as in most cartilages small,
flattened, and disposed horizontally; the deeper seated cells become
larger and longer; their axes, on the contrary, being directed either
vertically or obliquely to the surface ; sometimes also the cells,
although separated by distinct intervals, are arranged the one above
the other in such a manner as that the superior appears to be a con-
tinuation of the inferior; at others, an inferior cell appears to divide
into two others, placed above it, and thus represents a bifurcation.
Henle also states, that he has seen not unfrequently the outline of a
cavity prolonged from one longitudinal series of cells to a neighbour-
ing series. It is very possible, Henle goes on to observe, that these
cavities form part of a system of elongated canals, which, taking an
undulous course, and sometimes bifurcating, traverse the cartilage
from its inferior to its superior surface, and which, when one makes
a section, are divided into twro portions, the one remaining in one
segment, the other in the other segment. This structure, he proceeds
to remark, explains sufficiently why articular cartilages exhibit a
fibrous fracture, and why the earlier observers believed them to be
composed of fibres which ran perpendicularly to the thickness.
This ingenious notion of Henle, although it serves to account for
some hitherto unexplained phenomena connected with the articular
cartilages, is yet of very doubtful application even to them, and cer-
tainly no such arrangement of the cells and cavities as that just
described belongs to the majority of true cartilages, or to any of the
fibro-cartilages.
NSar the surface, the articular cartilages are more laminated, and
may be separated into thin lamellae.
* Anat. Gen., vol. vii. p. 366.
CARTILAGES. 309
In the smaller articular cartilages, the number of cavities and cells
is more considerable, and the superficial layer of cells is not so well
marked: the peripheral cells are small indeed, but for the most part
rounded; a few are found in the neighbourhood of the bone, of an
elliptical figure, but the middle layer presents circular cavities, with
cells which are either single or multiple.
Nuclei. — The nuclei contained in cartilage cells are mostly granular,
but sometimes present a smooth aspect, and then are scarcely to be
discriminated from particles of oil or fat: in form they are sometimes
rounded, but in general they are irregular in shape, and follow more
or less closely the contour of the cells in which they are enclosed;
they also frequently enclose a nucleolus.
Usually but a single nucleus is contained in each cell; occasionally,
however, two, three, and even several are included within it; and
sometimes it happens that one or more of these is invested by a dis-
tinct cell-membrane. (See Plate XXXI.)
The cells also include, as already remarked, particles of oil of a
globular form and of a shining aspect; it has been suggested that
these may probably in some cases be transformed nuclei.
The distinction of cartilages into true and fibro-cartilages, although
useful for the purposes of classification, is to some extent artificial;
since, on the one hand, some of the true cartilages, as old age
approaches, become converted into fibro-cartilage, and on the other,
the fibro-cartilages themselves, in the early period of their develop-
ment, do not contain fibres, the cellular substance being hyaline, and
identical with that of true cartilages.
The conversion of hyaline cartilage into fibro-cartilage has been
observed to occur only in those cartilages which are subject to
become ossified, as those of the ribs, the thyroid, &c.
Where ligaments are inserted* into true cartilaginous tissue, this in
the neighbourhood of such insertion always exhibits a fibrous struc-
ture, in consequence of the fibres of the ligament penetrating into
the inter-cellular substance. These fibres are of a nature totally
distinct from proper cartilage fibres, as will be seen hereafter.
FIBRO-CARTILAGES.
Fibro-cartilages differ chiefly from true or hyaline cartilages, in
that the homogeneous inter-cellular substance is replaced in them by
fibres endowed with elasticity ; a transformation of structure of
which we have seen that certain of the true cartilages are suscep-
tible. (See Plate XXXI.)
310 THE SOLIDS.
The fibro-cartilages include those of the articulations which are
united by synchondrosis, as the intervertebral cartilages, and that of
the symphysis pubis; the epiglottis and the cuneiform cartilages; the
articulating cartilages of the glenoid cavity, and of the head of the
superior maxillary-bone; the inter-articular cartilage of the sterno-
clavicular articulation; the cartilages of the ear, of the Eustachian
tube, of Santorini, and those of Wrisberg.
There are, however, other differences besides the structural one
alluded to; thus, fibro-cartilages are more opaque than the true, are
of yellow colour more or less deep, and are endowed with a higher
degree of elasticity and flexibility.
The fibres do not follow the same distribution in every fibro-
cartilage : thus, in the tube of Eustachius, in the symphysis pubis, in
the inter-articular cartilage of the sterno-clavicular articulation, in
those of the tempero-maxillary articulation they are placed nearly
parallel to each other; in the inter- vertebral cartilages, they ascend
vertically from one osseous surface to the other; in the cartilages of
the epiglottis and ear, they are curved and interlacing.
In the outer part of each inter- vertebral cartilage, the fibres form a
distinct and compact stratum of a yellow colour, no cartilage cells in
that situation intervening between them; the number of fibres, how-
ever, gradually diminishes towards the centre of the cartilage, which
at the same time becomes less and less dense and firm, until at length
in the very axis it is semi-fluid.
The cells of fibro-cartilages do not differ very materially in form and
structure from those of true cartilages ; they usually, however, contain
more fat, are more readily separable from the fibrous base in which they
are lodged, and oftener encountered in the condition of parent cells.
The cells of the inter-vertebral cartilages and of the epiglottis
present some interesting forms and modifications : thus, the cells
which are situated in the harder parts of those cartilages are, on a
vertical section, seen to be narrow and much elongated; while many
of those imbedded in their soft and central parts are large and per-
fectly globular; many others of these, again, are in the condition
of parent cells, and enclose either numerous nuclei or else many
perfectly-formed secondary cells ; lastly, cells occasionally present
themselves made up of concentric vesicles enclosed one within the
other. Groups of adherent nuclei are also frequently met with
deprived of an investing membrane. For representations of these
several forms of cells, see the figures.
CARTILAGES. 311
Henle* describes as occurring in the epiglottis certain large,
spherical, or oval cells, presenting in their interior an oblong cavity,
from which proceed little branched tubes, which extend in all direc-
tions, even to the surface of the cells. These cells would appear to have
some analogy with the osseous corpuscles. I have made diligent search
for them in the epiglottis, but hitherto have failed to meet with them.
The fibro-cartilages are not soluble to the same extent in boiling
water as the true, which are almost entirely so, and therefore yield
less chondrine or jelly. The cells of these cartilages also resist the
action of the water for a longer period than the inter-cellular sub-
stance, f
NUTRITION OF CARTILAGE.
Cartilages are among the number of non-vascular substances — that
is, they do not, in general, receive into their own tissue distinct
blood-vessels, but derive their nourishment from those which are
distributed to the parts adjacent to them.
Thus, the articular cartilages are supplied with nutriment from the
vessels which are so freely distributed to the extremities of the bones;
in young children, and sometimes even in adults, the synovial mem-
brane which covers the free surfaces of the cartilages also carries
vessels which assist in their nourishment.
The independent or figured cartilages, as the ribs, &c, are sur-
rounded by a membrane, composed of condensed cellular tissue,
called the perichondrium : in this membrane the vessels which afford
nutriment to the enclosed cartilages ramify. The ribs, moreover,
contain grooves or canals, which, commencing on the inner edge
of the rib, first run towards the centre, and then continue to pass
forwards for some distance : these canals also contain blood-vessels.
In the centre of ribs about to ossify, a distinct medullary canal,
containing blood-vessels in abundance, is clearly perceptible.
Vessels are also contained in the fatty masses enclosed in some
of the joints, and called the glands of Havers ; from these the
adjacent cartilages doubtless imbibe a portion of nutrient plasma.
Among fibro-cartilages, the synchondroses are stated to receive
vessels. Nerves have not, as yet, been discovered in cartilages,
which may be irritated for any length of time without the slightest
pain being occasioned.
* Anal. Gtn., vol. vii. p. 370.
f Meckauer (Carlilag. Slructura, 1836,) appears to have been the first to give,
under the direction of Purkinje, a complete and accurate description of the cartilages
of the human body.
312 THE SOLIDS.
During ossification, between the cartilage to be converted into
bone and that which is to remain as the articular cartilage, a layer
of vessels passes, which, as the ossification advances, gradually retire,
and wholly disappear soon after birth.
As cartilages do not contain vessels, they are not subject to those
disorders which depend upon errors of the circulation; that is, they
are not liable to inflammation and its consequences. Ulceration
of cartilages is indeed described by writers ; but this term is wanting
in accuracy when applied to the erosion of which cartilages are
susceptible, and which is effected not through any operation occur-
ring in the cartilage itself, but through the action of vessels which,
proceeding from the synovial membrane, dip down into the cartilage,
and occasion its partial absorption. For the same reason, cartilages
do not readily become atrophied by pressure : thus, when an aneurism
destroys the bodies of the vertebrae, the inter-vertebral cartilages are
not at the same time removed, but resist for a long period the con-
tinued compression to which they are subject.
There is, however, one description of cartilage in which blood-
vessels regularly appear, viz: cartilages of ossification, in which may
be included the costal and' thyroid cartilages, their presence proceed-
ing and accompanying the process of the formation of bone.
Cartilages, like all the extravascular tissues, imbibe fluid readily:
thus, when immersed in a coloured solution, they assume the tint of
the liquid in which they are placed. In jaundice, according to
Bichat,* they present a greenish yellow tint, from the imbibition of a
portion of the bile with which, in this disorder, the system is so
pregnant.
GROWTH AND DEVELOPMENT OF CARTILAGES.
Cartilages, as already observed, consist of cells imbedded in a hyaline
or fibrous base. In considering, then, the development of cartilages,
the growth of both the cells and the inter-cellular substance must be
discussed.
We will first describe the multiplication of cartilage cells.
The Cells. — Cartilage cells are multiplied in two ways.
1st. By the division of a single cell into two or more parts, each of
which becomes, when the separation is completely effected, a distinct
cell. The reality of this method of increase in the number of cells
will become evident, on the attentive examination of almost any thin
*Anal. Gen.,t. iii. p. 192.
CARTILAGES. 313
section of cartilage, in the cells of which, but especially in those placed
near the natural border, the several stages of their division may be
clearly and satisfactorily recognised. (See Plate XXX.)
2d. By the development of cytoblasts either in the inter-cellular
substance, or else in parent cells. This mode of increase is a true
reproduction, new cells being continually formed and developed.
The first process of multiplication is of a nature totally distinct from
reproduction ; for although by it the cells are multiplied, no new ones
are developed. There is the same difference between the two forms
of cells, that having its origin in the division of a single cell, and that
developed from a cytoblast, as there is between a slip and a seed.
(See Plates XXX. and XXXI.)
The parent or primary cells, filled with the second or even the
third generation of new cells, may be detected in abundance in almost
any cartilage, but especially in the inter-vertebral cartilages. It is
worthy of notice, that the parent cells are usually situated near the
centre of each cartilage, while the single cells, in which the process
of division is best seen, are mostly found outside these. From this
arrangement we may infer that the deeper-seated cells are older than
those of the circumference. Whether the latter are derived from the
former, or whether they are formed on the external margin of the
cartilage, it is not easy to decide ; it is most probable, however, that,
from the circumstance that the parent cells are principally found in
the centre of the thicker cartilages, and that it is in this situation that
ossification commences, that the second conjecture is the correct one.
It is a singular fact, that the development of cartilage cells may be
as readily followed out in old cartilages as in young, numbers of cells
in process of division and in the stage of parent cells being readily
distinguished in each. As after maturity cartilages do not undergo
any increase in size, and as from the preceding observations it would
appear that new cells are continually being evolved, it must be pre-
sumed that the very old cells are absorbed and their place supplied
by the younger ones.
In the multiplication of cartilage cells by division, a correspondence
may be traced between cartilages and many of the lower tribes of
animals and vegetables, especially with the majority of the algae ; and
in the development of secondary cells in parent cells, they exhibit a
still closer analogy with certain algae of the genera Hcematococcus and
Mycrocyslis, the cells of some of the species of which it would be
impossible to distinguish from the isolated cartilage corpuscles of the
epiglottis and inter-vertebral cartilages.
314 THE SOLIDS.
In these methods of multiplication, cartilage cells would appear
almost to stand alone in the animal economy: thus, it is certain that
the red blood corpuscles, epithelial cells, and their various modifica-
tions into epidermis, nails, pigment cells, and hairs, are not multiplied
either by division or by the development of secondary, enclosed in
primary or parent cells.
The analogy existing between the cells of cartilages and those of
certain algas has been noticed by Dr. Carpenter, in the third edition
of his "Principles of Human Physiology."
The Inter -cellular Substance. — Very young cartilages, and also the
smaller ones of adults, are constituted almost entirely of cells, with but
little admixture of inter-cellular substance. As, however, these young
cartilages grow in size, the relative amount of this substance increases,
and the space between the cells becomes greater.
The augmentation of the inter-cellular substance takes place prin-
cipally by a deposit of new layers on the exterior surface during the
period of the development of cartilages; this mode of increase is
proved by their separation after long-continued maceration into dis-
tinct laminae.
A second mode of increase of the inter-cellular substance has been
stated to exist by Henle,* principally in the cartilages of ossification,
and under no circumstances in the fibro- cartilages, viz : by the thick-
ening of the walls of the cells, which become confounded with or
melted down into the inter-cellular substance, the cavity in which the
cells are lodged being diminished, or this also augmenting at the same
time. The proofs adduced in favour of this method of increase are
not convincing.
It has already been stated that in the true cartilages which are
subject to ossification, fibres appear; these fibres, as well as the anal-
ogous ones of fibro-cartilages, are probably of a nature wholly distinct
from those of ordinary cellular tissue, and which have their origin in
cells ; under no circumstance can either cells or nuclei be discovered
in the fibres of cartilages.
Cartilage is not capable of regeneration: when it has been frac-
tured, the union of the surfaces is very incomplete, and principally by
means of cellular tissue.
The formation of cartilage almost invariably precedes the develop-
ment of bone, of which we shall shortly have to speak more particu-
larly in the Chapter on Bone.
* Anat. Gen., vol. vii. p. 376.
CARTILAGES. 315
Masses of cartilage are also occasionally produced upon the exter-
nal surface of the synovial membrane of joints; these are at first
peduncated, but at length cease to have any connexion with the organ-
ization, and move freely about in the cavity of the joints.
Occasionally, though rarely, cartilage is developed in the cellular
tissue of glands, forming a solid tumour, which was first described by
Muller, under the name of Enchondro?nab and of which I recently had
the pleasure of receiving a very excellent example from Dr. Letheby.
USES OF CARTILAGES.
The uses of cartilages are of a mechanical nature, depending upon
certain physical properties.
Thus, we find them to be situated in localities where solidity is
required in combination with flexibility and elasticity.
In the larynx, the flexibility and elasticity of cartilages assists in the
modulation of the voice.
In the nose, so liable to injury, their flexibility often allows this
organ to sustain severe blows without detriment.
The articular cartilages protect the bones from injury to which they
would be otherwise so subject in the sudden and violent exertions of
the body, as in jumping, on account of their solid and unyielding nature.
The inter-vertebral cartilages are exceedingly elastic and flexible,
and permit the free movement of the spinal column in almost any
direction, and which is so necessary in the execution of the various
motions of the body.
The articulations united by synchondrosis, as that of the pubis,
are remarkable for their strength, although at the same time it admits
a slight degree of extension and compression.
Lastly, the epiglottis is enabled to preserve the erect position so
essential to the maintenance of life in consequence of its exceeding
elasticity.
316 THE SOLIDS.
CARTILAGE.
[For an elaborate and complete account of "the intimate structure of
articular cartilage," see a paper on that subject, with plates, by Jos. Leidy,
M. D., of Philadelphia, published in vol. xvii. (new series) of the American
Journal of Medical Sciences, pp. 277-294.
The development of cartilage is of course best studied in the fetal subject.
In the adult, cartilage may be examined in their vertical sections.
Articular cartilage is easily separated from bone, after slight immersion in
acid.
Preparations of cartilage should be preserved in cells with fluid.
Plate LXX., fig. 5, Cartilage from the finger-joint, showing terminal loop-
ings of vessels.]
BONE. 317
ART. XV.— BONE,
The next tissue to be considered is the osseous.
Bones are divided after their form into long, flat, and irregular:
long bones consist of a body or shaft termed diaphysis, hollowed out
in the centre into the medullary canal, and of two extremities called
Epiphyses, and which in early life are distinct from the shaft; each
long bone, moreover, is made up of two modifications of bony struc-
ture, the cancellous and the tabular; the former is loose and reticular,
the latter hard and compact: of the one, the great bulk of the
epiphyses are constituted; of the other, the diaphysis is chiefly formed:
in flat and irregular bones, the medullary canal is wanting ; the first
consist of an inner and outer table of compact bony tissue, enclosing
a thin plate of cancellous structure, termed Diploce, and the latter
are composed principally of cancelli, enclosed in thin and irregular
osseous laminae.
STRUCTURE OF BONES.
The two elements into which all bones resolve themselves are
osseous corpuscles and laminae ; the latter, according to the plan of
their arrangement and development, give rise to the cancelli, medul-
lary canals, and plates of which bones are constituted.
Cancellous Structure.
The cancellous structure of bone is made up of thin and inoscu-
lating plates of bony matter, which enclose spaces between them, and
all of which freely communicate with each other : these spaces are
called medullary cells. Each plate is also compounded of several
laminae, in the intervals between which a few bone corpuscles exist.
The fact of the free communication of the medullary cells is proved
by the two following experiments :
Thus, when mercury is poured into a hole made in the exremity of
a long bone, or on the surface of a flat or short one, it will traverse
all the medullary cells, and escape by the apertures which exist
naturally on the exterior of bones.
Again, if a bone be cut through at one of its extremities, the
natural openings on its surface being at the same time closed, and if
318 THE SOLIDS.
then the bone be exposed to the action of heat, all the marrow will
escape slowly by the cut extremity.*
The spaces described by the medullary cells are irregular in size
and form, those which are first developed being smaller than those of
older formation (see Plate XXXIV. fig. 3, 4) : they are usually of
an elongated shape, their long axes being parallel to that of the bone
itself: when viewed transversely, they are seen to be more or less
rounded, but irregular in outline : it is in the transverse sections that
the bone cells and lamellae are best seen.
Medullary cells in the recent state are filled with fat vesicles, with
blood-vessels, and with granular nucleated cells analogous to those of
epithelium: these last occur in considerable quantities in the cancelli,
and especially in those of fetal bones, in which the fat vesicles are
for the most part absent. (See Plate XXX. fig. 4.)
They inosculate freely with the medullary canals situated in the
outer and compact plates of bone.
Canalicular Structure.
The compact tissue of bones is traversed by canals, which have
been termed medullary from the fact of their being in communication
in the long bones with the great central medullary cavity, and from
the circumstance of their being partly occupied with medullary
matter. They are also called Haversian, after their discoverer.
These canals are situated between the laminae of which bone is
composed, and take a course in the long bones, in which they are
best seen, parallel to their axes, being also joined together by short
transverse branches : they thus form a net- work of tubes analogous
to that exhibited by the minute vessels which they convey and pro-
tect; the form and sizes of the meshes vary: in the long bones they
are elongated. (See Plate XXXII. fig. 4.)
They communicate, in the long bones, with the medullary cavity,
dilating into cells or vesicles, from which a short tube proceeds
previous to their entrance into it; they also open upon the external
surface of all bones by somewhat expanded apertures, and inosculate
freely with the medullary cells.
Medullary canals are not all of equal diameter throughout the
compact tissue of a bone ; those situated between the external plates
are two or three times smaller than those which are placed more
internally. (See Plate XXXII. fig. 1.)
*Bichat, Anatomie Generate, t. 111. p. 25.
BONE. 319
In a transverse section, the canals are seen to be either circular,
oval, or rarely angular.
In the flat bones, the comse of the medullary canals is more irreg-
ular than in the long bones; in the parietal bones they proceed
diverging from the parietal protuberance towards the margins of the
bone; and in the frontal from the supra orbitar ridge towards the
coronal suture.
In the long bones, near their extremities and in the vicinity of the
articular cartilage, these canals end in blind or csecal extremities, a
single canal passing up into each of the prominences, into a number
of which the articular surface of bone is elevated.*
It is these canals, which impart the striated structure presented by
bone, and which is visible to the unassisted eye; in longitudinal
sections, they are frequently cut through, and their cavities exposed.
The contents of medullary canals are similar to those of the medul-
lary cells, of which they are to be regarded as a modification, there
being an insensible transition from the one to the other.
Drs. Todd and Bowman recognise two forms of Haversian canals,
one of which carries veins, the other arteries, a single vessel being
distributed to each ; those canals which contain the veins are stated
to be larger than those which convey the arteries, and to be dilated
into a pouch or sinus at the situation where two or more canals unite
to form a single larger tube.
Lame lice.
The more essential constituents of true and fully developed bone
are, as already observed, lamellae and bone cells; the medullary cells
and canals just described are merely definite spaces existing between
the lamellae, the arrangement and ultimate structure of which we shall
in the next place proceed to notice.
It is principally by the successive development of new lamellae that
bones increase in diameter; these are usually deposited in the direc-
tion of the axis of the bone; if, therefore, a transverse section of a
long bone be made and examined with the microscope, the lamellae
will be seen to be arranged as follows: First, several layers will be
observed to pass entirely round the bone ; secondly, others will be
noticed encircling each Haversian canal; and lastly, irregular and
incomplete lamellae occupy the angular spaces intervening between
* See Med. Chir. Rev. No. x. p. 528.
320 THE SOLIDS.
the sets of lamellae concentrically disposed around each canal. (See
Plate XXXII. figs. 1, 2, 3.)
The number of layers which pass interruptedly around the bone
are not very numerous, being generally less than twelve; the amount
of those which encircle each Haversian canal varies from two or
three to upwards of twelve, the smallest number of lamellae usually
appertaining to the smallest canal. (See Plate XXXII. fig. 1.)
Examined with an object-glass of the fourth of an inch focus, the
lamella, after the separation of its earthy matter by means of dilute
hydrochloric acid, exhibits a delicate structure, the precise nature of
which it is not easy to determine ; its surface will be seen to be marked
out into innumerable lozenge-shaped spaces, one side of each of which
is concealed by a dark shadow, and the divisions between which are
without shadow. (See Plate XXXIII. fig. 4.)
This interesting structure was first distinctly pointed out by Dr.
Sharpey,* who conceives that it arises from the crossing and union
of fibres; these, however, cannot be traced out and displayed as sepa-
rate fibres, owing, it is presumed, to their being united or fused
together at the points where they cross each other; it sometimes hap-
pens, however, that at the torn edge of a lamella a short projecting
process may be seen, which presents much the aspect of a true fibre.f
The appearance presented by a lamella thus figured might be com-
pared to the engine-turned case of a watch, and it might also be con-
ceived that it was produced by the union of a number of diamond-
shaped cells, and not by the crossing of fibres.
One argument in favour of the fibrous constitution of the lamellae
O
may be derived from the fact that the cancelli of bone in process of
development clearly exhibit a fibrous structure.
Cross sections of the lamellae may also sometimes be observed to be
marked with short and radiating lines, which most probably depend
upon the structure already noticed.
The osseous lamellae are likewise perforated necessarily with
numerous minute apertures occasioned by the canaliculi of the bone
cells, and which, when seen with a low power, appear like so many
* Quain's Anatomy, 5th edition, part ii. p. cxlii.
f It would appear to he prohahle, from the following quotation, that Henle had
seen the structure ahove described. " The lamellae examined on their flat side have
appeared to me to he generally hyaline or finely dotted, but sometimes also fibrous ;
the fibres are either pale, and as thougli composed of grains, or obscure and rugged;
one never succeeds in isolating them for a certain space, because they are branched,
interwoven, and, in a word, perfectly identical with the fibres of fibro-cartilages."
BONE. 321
small dots ; they contain, also, scattered throughout their substance,
multitudes of granules of earthy matter.
The only really necessary constituents of bone would appear to be
the cellular tissue and earthy matter. The combination of these two
forms bone in its simplest condition. The medullary cells, Haversian
canals, and bone cells, are connected only with the growth and nutri-
tion of bone, and occur seldom, except where the size of the bony
formation renders their presence necessary for its growth and support.
Bone Cells.
Distributed throughout the cancellous and compact portions of bone,
cells of a peculiar structure occur in considerable quantities.
Concerning the nature of these cells, much difference of opinion
prevails; by some they are described as mere vacuities existing in
the tissue of the bone; by others as hollow cells, as nuclei of cells,
and as true nucleated corpuscles. That the bone cells take then-
origin in nucleated cells, cannot be doubted.
The circumstances which have given rise to the notion of their
being mere vacancies or lacunae, are the passage of fluids through
them, their infiltration with solid matter, and the optical appearances
sometimes presented by them. All these circumstances admit, how-
ever, of explanation on the supposition of their corpuscular origin.
That they are derived from granular cells may be proved, it seems
to me, by the study of the development of bone, they being in growing
bones first traceable as nucleated corpuscles, a condition to which
they may be again reduced in an adult bone by the removal of the
earthy matter. This appearance is best seen in the large bone cells
of the Siren, Proteus, or Menobranchus.
The bone cells, which are very numerous, are situated between the
osseous laminae already described, and by which they are compressed;
they thus present in all sections of bone an elongated or flattened form,
and in transverse cuttings those facing the Haversian canals appear
not merely elongated, but also slightly curved, the concavity of the
arc being directed inwards towards the canals, and the convexity out-
wards in the contrary direction. (See Plate XXXII. Jigs. 1, 2.)
When viewed as transparent objects, they appear black, and when
as opaque, they are of a pearly whiteness.
From the margins of each bone cell proceed a number of branched
canals, which, passing through the lamellae situated on either side of
the cell, inosculate freely with the canaliculi given off by the bone
21
322 THE SOLIDS.
cells of the contiguous lamellae (see Plate XXXII. fig. 3) ; this pro-
cess of inosculation being frequently repeated between the cells of
each lamella, a communication is thus established between the me-
dullary cavity on which the canaliculi of the first series of cells
opens, the Haversian canals, and the external surface of the bone.
The reality of this communication may be attested, by applying a
drop of oil of turpentine to a section of dry bone placed beneath the
microscope, when the passage of the fluid through the bone cells may
be followed with the eye. This experiment was first suggested by
Drs. Todd and Bowman.
The canaliculi of bone cells treated with acid usually disappear, the
body of the cell alone remaining.
The size of the bone cell throughout the whole of that osseous ver
tebrate series, stands in relation to that of the red blood disc ; and Mr.
Quekett, who has instituted an inquiry into their form and size in a
great variety of animals, has arrived at the conclusion that the class
to which any animal belongs, whether that of Beasts, Birds, Reptiles,
or Fishes, may be determined by the two particulars referred to.
This discovery is likely to be especially useful in the determination of
the true position in the' animal series of many fossil bones, which but
for it, would have continued to be enveloped in uncertainty and
conjecture.
In many osseous fishes, the bone cells appear to be wanting, they
having merged into canaliculi, which are often of considerable size.
Marrow of Bones.
The medullary cavity of adult long bones, the medullary cells, and
the larger medullary canals, all contain a loose cellular tissue, in the
meshes of which a greater or less amount of marrow or fat cells is
enclosed. (See Plate XXX. figs. 3, 4.)
In foetal and very young bones the fat vesicles are wanting in the
three situations named, the place of fat being supplied by immense
numbers of the small granular nucleated cells, which have already
been referred to. (See Plate XXXIII. fig. 5.)
It has been stated that the medullary cavity, cells, and canals all
communicate freely; the marrow therefore and its enclosing cellular
tissue are every where continuous.
Periosteum.
The external surface of all bones, with the exception of their artic-
BONE. 323
ular extremities, is covered with a dense membrane composed of
fibrous tissue, which is very rich in blood-vessels, and which is called
the periosteum.
The internal surface of the medullary cavity, cells, and larger
Haversian canals, is also lined by a vascular membrane much more
delicate in structure, which may be regarded as an internal periosteum.
It is by means of the vessels which ramify through these mem-
branes that the nourishment of the bone is secured.
Vessels of Bone.
Bones are richly supplied with blood-vessels, which penetrate every
part of their structure.
Thus externally, branches, principally arterial, proceed from the
periosteum, enter the numerous apertures of the Haversian canals,
and, ramifying through these, form a capillary net-work; these external
periosteal vessels may be seen with the unaided eye, extending into
the bone like so many fine threads, on the cautious detachment of the
periosteum.
Again, in the long bones, a large artery penetrates by an oblique
canal situated at the junction of their upper' and middle thirds, into
the medullary cavity, and sends branches upwards and downwards,
which ramify on the membrane of the medulla or internal perios-
teum; some of these proceed onwards into the medullary cells, and
others inosculate with the capillaries of the Haversian canals already
referred to.
The flat and irregular bones are furnished not with a single vessel
of large calibre, but with several of smaller size.
These larger arteries are accompanied by veins, whereby a portion
of the venous blood is returned from the bone.
Breschet,* moreover, has described in the flat bones, and especially
in those of the cranium, a system of osseous canals, which contain
only veins, and which are furnished with valves, which is not the case
with the other veins of bones.
The walls of these canals, which ramify after the manner of vessels,
are pierced with apertures, by which they receive small capillaries:
they traverse principally the spongy portion of bones, afterwards they
pass through the compact part, and finally terminate on the external
surface of the bone.
* N. A. N. C. xxiii. P. i. p. 361.; Recherches Anat. Physwlog. el Pat. sur le Sys-
teme Veineux, Paris, 1829. fol.
324
THE SOLIDS
These canals are best seen in the flat bones of the cranium, which
should be dried, and the outer table of compact substance removed.
Lymphatics have been observed in some few instances in bone.
Nerves of Bone.
Nerves have not hitherto been satisfactorily traced into bones;
nevertheless, the great pain experienced in diseased conditions of
them proves incontestably the existence of nervous fibrillee.
GROWTH AND DEVELOPMENT OF BONE.
Growth of Bone. — The situations in which the chief increase of
bone occurs are commonly stated to have been accurately determined
by means of the different madder experiments instituted by numerous
observers.
If an animal be fed for a short time with the root of madder, its
bones will become tinged with the colouring matter of that plant,
between which and the phosphate of lime of the bone a great affinity
exists.
On a close examination of sections of a growing long bone it will
be observed, however, that the tissue of the bone is not uniformly
coloured, but that in a transverse cutting the colour is principally
situated in the outer part. The same fact is shown also in longitudi-
nal sections, which, however, if they embrace the entire length of the
bone, will also be observed to be tinged with the colouring matter
towards either extremity.
Again, if a magnifying glass be applied to a thin transverse section
of the growing bone of an animal fed upon madder, each Haversian
canal will be seen to be surrounded by its ring of colour. For this
beautiful illustration of the effects of madder we are indebted to Mr.
Tomes. (Plate XXXIII. fig. 6.)
These several observations have been presumed to prove that bones
increase in length principally by additions of new matter to their
extremities, and in breadth by the deposition of new laminae of bone
on their outer surface, as well as by the formation of fresh lamellae
in each Haversian canal, which last grow and expand in size simul-
taneously with the laminae placed external to them after their first
formation.
Now, although it is very probable that bones increase in diameter
to a great extent by the addition of new matter on the external sur-
face, and although it is quite certain that they become elongated by
BONE. 325
the formation of bony matter at their extremities, it appears to be
most clear that we are not justified in coming to any such conclusion
from the results of the experiments with madder. All that these cel-
ebrated experiments really seem to prove is, that bones in contact
with blood-vessels containing the colouring matter of madder, readily
imbibe and retain that principle in common with the liquor sanguinis.
The bones of old animals are coloured with much more difficulty
than those of young; a few hours in very young animals being suffi-
cient to ensure their colouration.
Development of Bone. — We come now to consider the exact pro-
cess of the development of bone.
Bone is developed either in membrane or in cartilage ; when in the
former, it may be termed intra-membranous, and when in the latter,
intra-cartilaginous ossification.
Intra-membranous Form of Ossification. — We will consider, first,
the intra-membranous form of ossification. Dr. Nesbitt* was the first
to distinguish between the two types of ossification. More recently
Dr. Sharpeyf has described clearly and satisfactorily the steps of the
intra-membranous development. This form he considers to belong
to certain flat bones of the cranium, as the parietal and portions of
the frontal and occipital bones, as well as to the outer surfaces of the
long bones.
The first perceptible ossification of the parietal bone, which may be
selected as one of the best examples of this form of osseous develop-
ment, consists of a net-work of spicula of bone, the outermost of
which radiate in lines towards the circumference, and are connected
by short transverse branches. (See Plate XXXIII. figs. 1, 2.)
As the ossification proceeds, the first formed spicula, in the centre
of the bone, become greatly increased in thickness, and the spaces
between them much diminished in size; the ossification continues
thus to spread and consolidate until the parietal meets the neighbour-
ing bone, with which it is at length united by suture.
If, however, the microscope be brought to bear upon one of the
newly-formed spicula before the entire bone has attained any con-
siderable development, it will be seen that the ossific deposit takes
place in the fibres of fibro- cellular tissue, intermingled with which
numerous granular and nucleated cells occur; these fibres, which are
disposed in bundles, invariably precede the deposition of bony matter,
* Human Osteogony, Lond. 1736.
f Dr. Quain's Anatomy, edited by Mr. Quain and Dr. Sharpey, 5th edition.
326 THE SOLIDS.
and mark out the course of the future spicula. (See Plate XXXII.
fig- 3.)
The granular cells just noticed have been observed by Dr. Sharpey,
who remarks upon their distribution in the direction of the future
spiculse, and who considers that they are connected in some way or
other with the process of ossification.
There can scarcely be a question but that they are the bone cells
in a rudimentary state, their conversion into which it is not difficult
to trace.
Now, it does not appear that cartilage is at all concerned in any
one stage of the development of the parietal bone of the human
embryo. In that of the sheep, and some other animals, a lamina or
cartilage is present in connexion with the parietal bone ; but this takes
no part in the process of ossification, but merely serves as a support
to the newly-developed bone, and extends beneath the first-formed
portion of it alone.
As the ossification advances still further, the interstices between
the first-formed spicula become filled up, grooves appear on the sur-
face of the bone; these radiate from the centre towards the circumfer-
ence, and ultimately become converted into canals, which, being lined
with a number of concentric laminae, at length constitute the com-
plete Haversian canals. The bone is then completely formed.
Intra-cartilaginous Ossification. — It has, until recently, been sup-
posed that the formation of bone always takes place in cartilage; this
notion, as we have seen, is erroneous.
Ossification is also usually described as the conversion of cartilage
into bone; this idea will be presently shown to be equally erroneous,
and the fact demonstrated that the intra-cartilaginous ossification does
not differ essentially from the intra-membranous form.
If the microscope be brought to bear upon a thin longitudinal sec-
tion of an ossifying foetal bone, in connexion with its cartilaginous
epiphysis, the following particulars will be noticed :
First, it will be observed that the cartilage cells in the neighbourhood
of the bone, instead of being scattered irregularly throughout the inter-
cellular substance, are arranged in several consecutive and alternating
rows or files, the lowermost of which dip into and are surrounded by
osseous cups and septa; that the cells forming the lower portion of
the lowest tier are larger, and less compressed, than those which enter
into the formation of the upper part of each lower series, and that they
are separated from each other by distinct portions of inter-cellular
BONE. 327
substance. Secondly, it will be remarked that the extremities of the
still soft bony spicula invade and extend into the spaces which inter-
vene not merely between the rows of cells, but also between the indi-
vidual cells, and further, that granular and probably cytoblastemic
particles are deposited in this inter-cellular substance, particularly
where this comes into contact with the cartilage cells themselves.
(See Plate XXXIV. figs. 1. 4.)
As the process of ossification advances, the cell-wall of the cartilage
cells becomes absorbed; granular corpuscles are next generated in
the primary cancellus ; after which the nuclei of the cartilage cells
(which are observed to become smaller, the deeper they lie in the
bone) are removed by absorption; finally, the small septa intervening
between the individual cartilage cells are removed, the larger medul-
lary spaces being thus formed. (See Plate XXXIV. fig. 4.)
Furthermore, in these precursory and even in the older spicula,
fibres analogous to those in which the spicula of the parietal bones
are developed, may be abundantly detected.
Such is a brief sketch of the several steps of the intra-cartilaginous
form of ossification.
Now, the process which we have just described, is constantly in
progress ; cartilage cells on the one side are continually being devel-
oped in the epiphysis; they are also constantly marshalling themselves
into rows or columns, the lowermost cells of which dip into the can-
celli and become absorbed ; on the other side, the cancelli of the bone
are continually invading the inter-cellular spaces of the cartilage.
It is thus that a bone grows in length. Each epiphysis of a long
bone, however, after a time, becomes a centre of ossification; this
proceeds to meet that of the shaft; a layer of cartilage usually, how-
ever, intervenes between the two, until the period of the full develop-
ment of the osseous system, when this layer becomes absorbed, and
the shaft and the epiphysis become consolidated by bony union. The
first trace of ossification of the epiphysis in the human subject is
usually apparent at about the ninth month.
We have now to ask ourselves the question, how does the bone
increase in diameter? We have shown that it is generally considered,
as proved by the madder experiments already referred to, that a long
bone increases in breadth by the deposition of new lamellae at the
circumference, as well as in the cavities of ihe medullary and Haver-
sian canals; but we have seen also from what has been already said
in reference to the different sizes of the external and internal Haver-
328 THE SOLIDS.
sian canals and their mode of formation, that each of these canals is
continually undergoing a process of expansion, and it is by this
expansion that the chief increase of the diameter of a bone takes place.
It was formerly supposed that a layer of cartilage existed in all grow-
ing bones on their external surfaces, but we now know that such is
not the case, and that the new osseous deposit takes place in fibres.
If it were necessary that a layer of cartilage should exist in the situ-
ation named, it would be equally requisite that it should be present in
each medullary cell, and in each Haversian canal.
The small granular corpuscles already referred to as occurring in
the cancelli of all bones, but especially in those of the foetus, it would
thus appear are developed in considerable quantities at a very early
period of the development of bone ; they are generally apparent in the
third or fourth tier of the first formed and small cancelli, and while
the nuclei of the cartilage cells yet exist. (See Plate XXXV. fig. 3.)
It will now be perceived that the intra-cartilaginous form of ossifi-
cation is identical with the intra-membranous type in all essential
particulars.
It will also readily be seen that this view of the process of ossifi-
cation differs very considerably from the more recently expressed
opinions on the subject ; those, for example, of Drs. Todd and Bow-
man, and of Mr. Tomes.
The authors of the "Physiological Anatomy" consider that the
nuclei of the cartilage cells become developed ultimately into the
bone cells.
There are many considerations which would lead to the conclusion
that such a transformation is but little probable, the following of
which may be referred to:
The formation of bone, independent of cartilage, as in the intra-
membranous type of ossification.
The small number of the cartilage cells, compared with the vast
quantities of bone cells which exist in even a young bone.
The impossibility of explaining why the permanent cartilages
should not, like the temporary, be constantly subject to ossification,
since they are both organized in precisely the same manner.
The proof that cartilage cells have no further stage of development
to pass through, manifested by the fact of the occurrence of parent
cells in all cartilages, whether temporary or permanent.
The chief new points contained in Mr. Tomes's views* are the
* See Art. " Osseous Tissue," Cyclop of Anatomy and Physiology.
BONE. 329
ossification of the walls of the several cartilage cells which form each
roll or column, and the conversion of a number of these, by the
absorption of the contiguous walls of the cells into a single cavity or
tube, which becomes filled with a granular blastema; this tube Mr. T.
considers to be an Haversian canal, and its wall to constitute ulti-
mately the outer lamina of such canal.
The arguments adduced in disproof of the opinion that the nuclei
of the cartilage cells become converted into bone corpuscles, apply
with equal force against the idea of the calcification of the walls of
the cartilage cells.
Bone Cells. — Bone cells, then, according to the views of the author,
are not transformed nuclei of cartilage corpuscles, but take their
origin in distinct granular cells, which may be clearly seen in the
growing spiculae of bone dispersed among the fibres in which the
earthy matter of bone is first deposited, and which at length become
entirely imbedded in the earthy deposition.
As, however, it is most probable that a development of bone cells
and new laminae of bone are ever in progress even in adult bones,
we should expect to encounter in the cancelli of bones of every age
fibres of cellular tissue and granular cells; both these do occur in
them, and especially the latter, which are met with in great numbers.
These granular nucleated cells are more numerous in foetal and
young bones than in those of older formation ; in the former, indeed,
they almost entirely fill up the cavities of the cancelli : in the latter,
although they are still numerous, their place is supplied with fat
vesicles, which are not present in the former.
It seems to me to be not improbable that two kinds of granular
cells may exist in the medullary spaces, &c, one consisting of rudi-
mentary bone cells, and the other connected with the elaboration of
marrow, which occupies the medullary cavity, medullary cells, and
larger Haversian canals.
It might be supposed that these granular cells were the white cor-
puscles of the blood escaped from the ruptured vessels, the red blood
discs having been absorbed ; this notion is, however, disproved by the
fact that many of them are much larger than the colourless corpus-
cles of the blood. (See Plate XXXIII. Jig. 5.)
The existence of a granular blastema in the cancelli, &c, of bones
was first observed by Drs. Todd and Bowman,* who considered that
it was concerned in the development of blood-vessels.
* Physiological Anatomy, chap. v.
330 THE SOLIDS.
Presuming it to be proved that the bone cells are derived from true
corpuscles, we have yet to decide whether we are to believe with
Schwann,* that they are complete cells, and that the canaliculi are
prolongations of the walls of these cells ; that, in fact, they possess a
structure conformable with that of the stellate pigment cells of the
skin of the frog, or of the lamina fusca of the eye ; whether we are
to consider with Gerber,f Bruns,J and E. H. Mayer,§ that they are
the nuclei of primitive elementary cells, and that the canaliculi are
prolongations of these; whether, again, we are to regard them with
Henle|| as the cavities of cells, the walls of which have become
thickened, and the canaliculi of which proceed from the central cavity
through the thickened walls of the cells, as do the porous canals of
many vegetable cells; lastly, whether we are to believe, with Todd
and Bowman, that the canaliculi proceed from the nucleus, which
afterwards becomes absorbed, and that thus the lacuna is left.
That the first view is the correct one, and that the bone cells are
to be regarded as complete corpuscles, the canaliculi of which are
formed by the extension of the cell wall, is, I think, proved by watch-
ing the formation and development of bone cells in growing spiculae
and by the action of dilute hydrochloric acid, which, by removing
the earthy matter, allows the granular texture, which originally char-
acterized them, to be again seen.
The last points left for consideration in reference to the develop-
ment of bone are, the modes of formation of the medullary cavity,
medullary cells, and Haversian canals.
Formation of Medullary Cavity. — Traversing the substance of
each cartilaginous epiphysis, a number of large and branched canals
may be seen in both transverse and longitudinal sections. (See Plate
XXXV. figs. 1, 2.)
The majority of these proceed directly from the ossified part of
the shaft in connexion with the epiphysis ; in this situation they are
of larger size, and are also fewer in number, than they are higher up
in the epiphysis, not exceeding usually five or six, but becoming multi-
plied, by the giving off of branches, to as many as fourteen or sixteen ;
others, however, enter the epiphysis from the sides, near the junction
of the bone and cartilage.
The interior of these canals is occupied with blood-vessels and
* Mikroskopische Untersuchungen, pp. 35. 115.
f Allgemeine Anaiomie, p. 104. \Ibid. pp. 240. 252.
\ Miiller, Archie. 1841, p. 210. II Anal. Gen. t. vii. p. 409.
BONE. 331
with granular nucleated cells, precisely like those existing in the
medullary cells of bone. (See Plate XXXV. fig. 3.)
The cartilage cells in a transverse section of the canals immediately
surrounding their orifices are disposed in a rayed manner.
Having thus described the structure, contents, and distribution of
these canals, we will next inquire their use. (See Plate XXXV.
tig. 3.)
If a number of transverse sections be made, not merely of the
cartilaginous epiphysis, but also of the bone in connexion with it,
and if these be examined in the order of their removal, it will be
observed, first, that in those sections which are made from the cartil-
aginous epiphysis most removed from the bone, the apertures of
these canals are small and numerous (see Plate XXXV. fig. 1) ;
second, that in the sections taken from the proximal end of the epiph-
ysis the canals are fewer in number and their orifices larger (see
Plate XXXV.) ; thirdly, that in other slices, which include a portion
of both cartilage and bone, the latter always commences on the
circumference of the section, proceeding gradually inwards, the
portion of cartilage surrounding the canals in question being the last
to become ossified (see Plate XXXV. figs. 2, 3) ; fourthly, in
cuttings made below the cartilage and through the bone, spaces four
or five in number, filled with granular cells corresponding in situation
with the afore-described canals, will be observed; fifthly, in others
carried still deeper into the bone, these several apertures will have
coalesced into one large space — the rudimentary medullary cavity.
From these several particulars, I therefore infer that the canals in
question are intimately connected with the formation of the medullary
cavity ; and that the absorption of the cancelli situated between each
of them is brought about by the vessels contained within them, aided
also probably by the granular cells.
Were the canals merely destined to convey to the cartilage the
nourishment necessary for its transformation into bone, it might be
expected that they would serve as so many centres from which the
ossification would proceed ; we have seen, however, that the cartilage
in their immediate vicinity is the last to be removed, and its place
supplied by bony cancelli.
Medullary Cells. — The primary cancelli are small, studded with
granules, form closed cavities, and do not contain bone cells. (See
Plate XXXIV. figs. 2, 3.) The secondary and larger cancelli are
formed by the absorption of the numerous septa of the primary
332 THE SOLIDS.
cancelli ; they do not form closed cavities, but communicate freely
together, and contain bone cells imbedded in their parietes. (See
Plate XXXIV. fig. 4.)*
Haversian Canals. — The Haversian canals are generally described
as being formed by the filling up of certain of the medullary cells, in
consequence of the successive deposition of new laminae of bony
matter. It seems to me, however, to be very questionable whether
they are formed in the manner indicated, and if so, such is assuredly
not the general mode of their formation.
I am induced to take a different view of their formation, and con-
sider they originate as follows :
The surface of all bones, whether long, flat, or irregular, is observed
to be marked with numerous grooves of different sizes and depths.
In the recent state, these are occupied with blood-vessels, and it is
around them that successive layers of bone are deposited, until at
length the vessels become entirely included, and a perfect canal is
formed.
In transverse sections of long bones, grooves and partially developed
canals may generally be seen along the outer margin of the cutting.
This view of the formation of the Haversian canals also accords
well with other characters presented by transverse sections of bone.
Thus, in all such, it will be seen that the smallest Haversian canals
are situated in the external part, while the larger canals are placed
internal to these : it will also be observed, that the smaller canals are
surrounded by the fewest number of concentric lamellae, and the
larger by the greatest number. (See Plate XXXII. fig. 1.) Now, the
fact of an additional number of lamellae encircling the larger canals
proves two things: first, that these large Haversian channels are of
older formation than the small; and second, that each lamella grows
or expands after its deposition, whereby the calibre of such canals
becomes increased, which is contrary to the generally entertained
notion of the formation of the Haversian canals, viz : by the filling up
of the large cancelli, brought about by the continual deposition of
new osseous lamellae, the outermost of which, for such a result to
ensue, must remain stationary in point of size.
ACCIDENTAL OSSIFICATION.
The abnormal growth and development of bone is a very common
pathological occurrence. Thus, we have it occurring on the surface
* See No. x. Med. Chir. R. p. 528.
BONE. 383
of the bones themselves in the form of exostoses, in the permanent
cartilages, in the cellular tissue of muscles, glands, the ovaries, mem-
branes, as the coats of the arteries, and probably occasionally also
in that of every other tissue and organ of the body.
It is not, however, every ossific deposit which presents all the
characters of bone: thus, those contained in the ovaries, in the
mesenteric glands, and in the coats of the arteries, usually want the
more conspicuous elements of bone, the bone cells and lamellae,
although these have been met with in ossific depositions remote from
all connexion with bone.
In the reparation of fractures, we have a development of true bone
preceded by the formation of cartilage.
334 TH"E SOLIDS.
BONE.
[Longitudinal and transverse sections of bone, to display the true struct-
ure, require so much time and trouble in the preparation, that when it is
possible to purchase them, this course will be found to be more advisable.
For those who desire to make their own preparations, the following instruc-
tions are added :
A section, either longitudinal or transverse, having been made as thin as
possible with a fine saw, it must be reduced still farther by a flat file.
When this process cannot be farther carried on, the section is to be placed
between two hones, and being kept moistened with water, the honing is to
be pursued until the section becomes sufficiently thin to show the structure.
This point should be ascertained by occasional observations with a low power
of the microscope. When sufficiently reduced, the section may be polished
by carefully rubbing it on a strip of chamois-leather with putty-powder.
If it be very thin, it should be mounted dry ; in this condition, a good pol-
ish will much increase its value; but if the section be not very thin, it
should be made more transparent by being mounted in balsam; in this
method, no polish will be necessary.
Mr. Quekett has observed that in some instances when the bone was
deposited in balsam, and heat then applied until the balsam has boiled, the
structure of the bone has been beautifully displayed.
Sections of bone, before being mounted, should be cleansed from grease
and dirt by being soaked for some hours in sulphuric ether.
" The vessels of bone may be recognised while it is yet fresh by the colour of the
blood contained in them, but they are rendered much more conspicuous by injecting
a limb with size and vermilion, depriving the bones of their earth by means of an
acid ; then drying and putting them into oil of turpentine, by which process, the
osseous tissue is rendered transparent, while the injected matter in the vessels retains
its red colour and opacity."*
As already stated in the text, the lamellae are easily separated by macera-
tion in dilute hydro-chloric acid.]
* "Quain's Anatomy," by Sharpey and Quain, 5th ed.
TEETH. 335
ART. XVI. — THE TEETH.
The tissue of the teeth is to be regarded rather as a modification
of the osseous, than as a distinct type of structure : the truth of this
remark is especially apparent on an examination of two of the three
substances which enter into the formation of each tooth, viz: the
cementum and dentine ; the third constituent, the enamel, is more
nearly related in its organization to the epithelium, of which indeed
it is a condition.
Each tooth consists of two parts: the body or crown, and the root
or fang; the limits of these are indicated by a slight contraction
called the neck; the crown is either simple or divided, and the same
is the case with root also : those teeth which have a simple crown are
called incisors and canines, those with a double crown bicuspids, and
those with the crown quadruply divided molars. Again, the sub-
stance of each tooth is divisible into three portions, each of which
presents characteristic differences; these have received the names of
dentine, cementum, and enamel.
The dentine, also called the ivory, forms the chief bulk of the tooth,
occupies a central position, and its interior contains the pulp cavity.
The enamel forms a layer of compact substance, which immediately
surrounds that portion of the dentine of which the crown of the
tooth is made up.
The cementum, also called crusta petrosa, has a distribution the
very reverse of the enamel, and extends principally around the fangs
of the teeth, and terminates at the neck of the tooth, in fact, just
where the enamel commences.
STRUCTURE OF THE TEETH.
Having thus sketched the general position of the three constituents
of the teeth, the consideration of the intimate structure of each may
next be entered upon.
Dentine. — The dentine is constituted of numerous tubes imbedded
in an inter-tubular substance; these tubes commence at the pulp
cavity, on the surface of which they open, and from which they
proceed in a radiate manner, terminating on the borders of the
dentine ; those arising from the upper part of this cavity ascend almost
vertically, those from the sides more obliquely, and those from the lower
portion pass either horizontally outwards, or else descend somewhat.
336 THE SOLIDS.
These tubes diminish in size from their commencement to their
termination: they are branched; at first they divide in a dichotomous
manner; their subsequent ramifications are numerous, minute and
arborescent, and they inosculate freely with the similar branches
proceeding from the adjacent tubes : those tubes which proceed
towards the cementum are remarkable for the very great number of
branches into which they divide.
The tubes of the dentine in their passage outwards do not run in
straight lines, but describe in their transit two or three large curves,
and each of these primary curves, when examined with a higher
power of the microscope, will be observed to be made up of numerous
smaller and secondary curves ; both the large and small curvatures
of one tube correspond with those of another.
Such is the usual course and distribution of the tubes of the dentine :
several modifications of them, however, still remain to be noticed.
Thus, sometimes a tube in its passage will dilate into a bone cell,
and again proceed onwards to its destination as a tube; at others, a
number of them, even in the centre of the dentine, will break up and
form a cluster of bone cells; again, at others, the tubes frequently
become transformed into, or terminate on the margin of the dentine
in bone cells. This gradual transformation of the dentinal tubes into
bone corpuscles, and their termination in the same, is especially seen
in that portion of the dentine contiguous to the cementum.
The usual method of termination of the dentinal tubes, is in fine
and inosculating branches on the surface of the dentine. Sometimes,
however, the tubes anastomose in a peculiar manner, and form distinct
loops; at others, the terminal branches pass out of the dentinal sub-
stance, and extend either into the cementum or the enamel; this
extension into the former is a very frequent occurrence.
For illustrations of these several modifications, the majority of
which have been pointed out by Mr. Tomes, in his excellent lectures,*
see the figures.
The surface of the dentine presents many elevations and depres-
sions : to these the enamel is accurately adapted ; it also exhibits the
hexagonal impressions of the enamel fibres.
The substance of the dentine is seen also occasionally to be trav-
ersed with canals for blood-vessels, analogous to the Haversian canals
of bone.
* See " Lectures" in Medical Gazette.
TEETH. 337
The pulp cavity of the teeth of old persons frequently becomes
filled up, and even obliterated, by a secondary formation of dentinal
substance, and which may be called the secondary dentine. This
dentine results from the ossification of the pulp by the vessels of which
it is ttaversed, and from the margins of the canals containing which
the dentinal tubes proceed in a radiate manner. (See the figures.)
Mr. Nasmyth regarded this secondary dentinal formation as dis-
tinct from the other structures of the tooth, and called it the fourth
dentinal constituent.
The dentinal tubes form but one element of the dentine ; the other
is the inter-tubular substance.
This is described by Mr. Nasmyth as constituted of elongated cells,
in the form of bricks placed end to end, and a tier of which exists
between every two tubes : Henle, on the other hand, declares it to be
fibrous. It would appear not to present any regular tissue, but to be
simply granular.
Occasionally, I have encountered in it globules of various sizes
refracting the light strongly, and presenting the appearances of oil or
fat vesicles. It has occurred to me that these might be fat cells
which had become included in consequence of the ossification of the
pulp, and which always contains a greater or less quantity of fat
cells. (See figure.)
Some sections of dentine which I have examined have exhibited
numerous reticulated markings, the results of fracture of the inter-
tubular tissue, and occasioned probably by the preparation of the
section. Fracture of the dentine is capable of reunion.
Cementum. — Of the cementum it will not be necessary to say very
much, it possessing the structure of bone, and containing both bone
cells and Haversian canals; the latter, however, but seldom. (See
the figures.)
The quantity of cementum differs in different teeth ; in many cases
it is very inconsiderable, but it usually increases with age.
In those cases in which there is but a slight development of
cementum, a layer of considerable thickness, formed of numerous more
or less hexagonal cells, and extending over the whole of that portion of
the dentine not covered by enamel, may, in most cases, be clearly seen.
This layer, Mr. Tomes speaks of as a granular layer; it is, however,
distinctly and regularly cellular. It is not easy to decide whether it
should be regarded as a distinct and permanent structure of the tooth, or
22
338 THE SOLIDS.
whether it merely forms the basement substance in which the cementum
is developed; my own impressions incline to the former view.*
A layer of granules, having the aspect of imperfectly developed
bone cells, is usually situated apparently between the dentine and
cementum, but really in the substance of one or other of these; this
layer might well be called the granular layer, and to it the description
of Mr. Tomes seems more applicable.
Mr. Nasmythf describes the cementum as passing over the entire
surface of the enamel of the tooth ; this would appear, so far as the
human tooth is concerned, to be an error. A cellular lamina, how-
ever, does really invest the enamel in very young teeth, but this is
soon worn away: this layer, however, has nothing to do with the
cementum, but is considered by Mr. Tomes to be derived from the
inner surface of the membrane of the tooth sac. It may be seen in
the teeth of the calf and horse.
Cementum is rarely, if ever, developed in the pulp cavity, although
it has been stated to be so by many observers. The cementum is not
unfrequently traversed by tubes, similar to and derived from those of
the dentine.
It will now be very evident that dentine and cementum do not
differ essentially from each other, and that both are but modifications
of ordinary bone.
Enamel. — Examined with an object-glass of one-fourth of an inch
focus, the enamel exhibits a fibrous appearance.
The fibres radiate outwards from the surface of the dentine, some-
what in the same manner as do the dentinal tubes themselves; they
are simple, short, somewhat attenuated towards either end, and pass
towards the margin of the enamel in a waved manner, sometimes
decussating, forming plaits or folds, and this occurs especially when
the surface of the dentine is concave. Viewed with a glass of the
eighth of an inch focus, they present the appearance of elongated and
many-sided crystals, and in transverse sections they are seen to be
hexagonal or polygonal ; in some instances, however, and especially
* The following is Mr. Tomes's description of this layer : " In the inter-tubular
tissue, hemispherical or elliptical cells are found, especially near the surface of the
dentine of the fang, where they form a layer joining the cement. This, in a paper
read before tbe Royal Society, I described as the granular layer; on the coronal sur-
face of the dentine they are not numerous. With these cells the dentinal tubes com-
municate, as do others coming from the cemental cells."
f Memoir read before the Medico-Chirurgical Society, by Alexander Nasmyth, Jan.
22d, 1839.
TEETH. 339
in the enamel fibres of young teeth, a minute canal may be traced
running along each fibre. (See the figures.)
It is uncertain whether each fibre is constituted of a single cell, or
whether several unite to form it : the appearance, in some cases, of
faint transverse markings would render it probable that the latter
opinion is the correct one.
Near the surface of the dentine, linear interspaces may sometimes
be noticed between the enamel fibres; with these spaces the tubuli
of the dentine frequently communicate, and when they exist in any
number, or extend nearly through its entire thickness, they produce
a pearly appearance of the enamel, and render it brittle.
Thin longitudinal sections of the enamel, in connexion with the
dentine, generally exhibit numerous linear fractures, which extend
through its entire thickness, and which most probably arise from
their mode of preparation. Sections of enamel also usually present
numerous wavy lines, and which are occasioned by the instrument
employed in making the cuttings.
Structure of the Pulp.
The centre of the dentine of all teeth is hollowed out into a cavity;
this is occupied with a soft and reddish mass, easily separable from
the walls of the cavity, the pulp.
The pulp is made up of numerous blood-vessels, the walls of which
are constituted of delicate and nucleated cells, of nerves, or ganglionic
cells, and larger granular cells placed principally on the surface of the
pulp, external to the other structures which enter into its formation.
These external granular cells are supposed to play an important
part in the development of the dentine, and to which more particular
reference will be made hereafter.
The pain experienced in tooth-ache arises from inflammation of the
nerves of the pulp, and which is frequently left exposed to the contact
of the air in consequence of the removal of the dentine, by which in
sound teeth it is enclosed, as the result of caries.
DEVELOPMENT OF THE TEETH.
The subject of the development of the teeth may be considered
under two heads : under the first, the general development of the teeth
will be briefly noticed; and under the second, the special develop-
ment of their several constituents will be treated of.
Into the various particulars in reference to the general develop-
340 THE SOLIDS.
ment of the teeth as organs, it would be inconsistent with the design
of this work to enter at any length. It will be sufficient to observe,
that preparations are made for the formation of the milk teeth at a
very early period of intra-uterine life ; that the first trace of the future
tooth is manifest in the form of a papilla placed in the primary dental
groove, and consisting of granular and nucleated cells ; that around
this papilla a membrane is developed, with an open mouth, thus form-
ing a follicle; from the margins of this aperture processes of the
mucous membrane, of which the follicle is constituted, are developed,
and these uniting with each other close the opening, and convert the
follicle into a sac. With the closure of the mouth of the follicle, the
first or follicular stage of the development of the teeth is terminated,
and the second or saccular stage commences. The number of oper-
cula developed from the margins of the follicles is determinate, being
two for the incisives, three for the canines, and four or five for the
molars. In the second or saccular stage, the papilla takes the form
of the tooth, of which it is the representative, the base dividing in the
case of the molars into fangs, and its apex assuming the shape of the
crown of the tooth, in the place of which it stands : in this stage also
a blastemic matter, consisting of plasma and nucleated cells, is devel-
oped in the space intervening between the papilla and the sac, and
adherent to the inner surface of the membrane of the latter, by which,
indeed, it is generated; lastly, the papillae become capped with tooth
substance or dentine.
With the passage of the teeth through the gums the saccular stage
terminates, and the third or eruptive stage is entered upon.
The second or permanent teeth pass through stages precisely sim-
ilar to those of the first or milk teeth, the papillae and follicles being
developed in crescent-shaped depressions placed in the posterior walls
of the follicles of the milk teeth, and which together constitute the
secondary dentinal groove.*
Having now obtained a general idea of the development of the
* For further particulars relating to the general development of the teeth, consult
the admirable paper of Mr. Goodsir, contained in the Edinburgh Medical and Sur-
gical Journal. From the researches of that gentleman we learn that the papillee of
the teeth appear in the upper jaw before the lower; that those of the milk teeth are
developed in three distinct divisions — a molar, a canine, and an incisor; that the molar
is the first formed, the canine the second, and the incisor the third; also, that the first
molar is developed before the second, and the first incisor before the second. In the
permanent teeth the papillse, with the exception of the anterior molar, appear at the
mesial line first, and proceed backwards.
TEETH. 341
teeth, we shall be prepared to understand the mode of development of
the individual tissues of the teeth, a subject which has been studied
more particularly by Mr. Nasmyth, Professor Owen, and Mr. Tomes.
Formation of the Dentine. — It would appear to be a universal law
of development, that all animal and vegetable tissues should take their
origin in cells; of this law the teeth present a striking and beautiful
example.
Thus, the dentine is formed out of the cells placed on the formative
surface of the papilla or dentine pulp. This view of the formation of
the dentine originated with Mr. Nasmyth,* and its accuracy has been
confirmed by the investigations of subsequent writers, and especially
by those of Professor Owen and Mr. Tomes.
Mr. Owen, in his work, "Odontography," describes with great
minuteness the several steps of the conversion of the cells of the pulp
into dentine, and also enters upon the consideration of the develop-
ment of the other tissues of the teeth.
According to Mr. Owen, the cells of the pulp, which are larger and
more numerous on the surface, become arranged in lines which are
placed vertical to that surface; subsequent to this arrangement, the
nuclei are seen to divide, first longitudinally into two portions, each
of which becomes a perfect cell, also provided with a nucleus; these
again divide, but in a contrary direction, viz : transversely ; thus, four
secondary cells are formed within the cavity of the primary cell, and
out of its single nucleus. The number is not, however, limited to
four, but each nucleus may give origin to many secondary cells. The
primary cells are placed end to end, as are also the secondary cells;
these last elongate considerably, until at length they coalesce, thus
forming the tubes of the dentine ; the primary cells remaining as such,
and in some adult human teeth being faintly visible. The primary
and secondary cells, however, although placed end to end, do not
form straight lines, but describe greater and lesser curves, the greater
being formed by the primary cells, and the lesser by the secondary;
these are the curvatures to which reference has been made in the
description of the tubes of the dentine.
The views of Mr. Tomes,f although not essentially at variance with
those of Professor Owen, yet differ from them in some important par-
ticulars. Mr. Tomes describes the primary cells themselves as dividing
*" Memoir on the Development and Organization of the Dental Tissues," by Alex-
ander Nasmyth, August, 1 836.
t Medical Gazette, Lecture V.
342 THE SOLIDS.
longitudinally into two or more secondary cells, but not transversely ;
subsequent to this division, each cell elongates, and at length unites
with those above and below it ; thus forming the dentinal tubes. Some-
times two cells unite with but a single cell placed beneath it, and it is
in this way that the branches of the dentinal tubes are produced,
Thus, according to Mr. Tomes, the wall of the primary cell, as well
as its nucleus, enters into the formation of the dentinal tubuli ; while,
according to Professor Owen, the nuclei alone give rise to these tubes,
the walls of the parent cells not undergoing elongation, but remaining
to constitute a considerable portion of the inter-tubular tissue.
In the human tooth I have been unable to detect the existence of
the primary cells of the dentine.
Covering the dentine pulp, a thin transparent membrane exists;
this, on its outer surface, is marked with numerous hexagonal depres-
sions, into which the enamel fibres are received.
Formation of the Enamel. — Reference has been made to a blastemic
matter, consisting of nucleated cells imbedded in a granular matrix,
and situated between the dentine pulp and the inner surface of the
sac of the tooth; this is the enamel pulp.
The cells of which this is formed are larger than those of the den-
tinal pulp, more transparent, and with nuclei which are less distinct;
they adhere to the inner surface of this sac, which is formed of a pro-
cess of the mucous membrane of the mouth itself, and from which,
indeed, they are evolved.
This membrane, like all mucous membranes, consists of two layers,
an outer basement of fibrous and vascular layer, and an inner colour-
less and blastemic layer; and it is from this last that the enamel cells
proceed. It is marked with depressions similar to those existing on
the surface of the membrane of the dentinal pulp, and into which the
terminations of the fibres of the enamel are received.
It is out of the cells just described that the enamel fibres are formed,
and this in a manner almost similar to that in which the tubes of the
dentine are themselves developed; thus the cells are first arranged in
vertical lines ; these commence in the depressions on the inner sur-
face of the tooth sac, and proceed from without inwards. The cells
next elongate until they touch each other by either short or oblique
surfaces; some of them coalesce by their extremities, and thus form
fibres in which earthy matter is deposited, and which at length ter-
minate in the hexagonal depressions situated on the outer surface of
the membrane of the pulp of the dentine.
TEETH
313
The nuclei elongate with the cells, and either disappear altogether,
or else remain as minute cavities running down the centre.
At first the union between the fibres is but slight, so that in newly-
formed enamel they may be easily separated from each other when
placed in water, to which they will impart a whitish appearance, in
consequence of their separation and diffusion through the fluid.
According to Mr. Tomes, also, numerous spaces exist between the
fibres in newly-formed enamel; and it is owing to the presence of
these that young enamel owes its opacity and brittleness.
We thus perceive that the enamel is to be regarded rather as a
modification of the epithelium than of bone.
The development of both dentine and enamel may be well studied
upon the teeth of young pigs, or kittens, at the birth.
Formation of Cementum. — The cementum pulp is formed between
the external surface of the dentine and the internal of the sac of the
tooth, it being intimately united to both.
It consists, like the pulps of the other tissues of the teeth, of nucle-
ated cells imbedded in a granular matrix: these cells are described
by Mr. Tomes* as resembling those of temporary cartilage, being oval
in shape, and having their long axes placed transversely, and at right
angles, to the length of the tooth.
The cells nearest the surface of the dentine are the first to become
ossified; and when their ossification and development is completed,
they form the stellate or bone cells of the cementum. Some consider
that the nuclei of these cells alone give origin to the bone cells, and
appearances may be observed, even in adult cementum, which are
favourable to this opinion.
The cementum is often seen to be traversed by fibres derived from
the outer layer of the membrane of the tooth-sac, as well as by tubes
prolonged into it from the dentine.
Notice has already been taken of the small hexagonal cells con-
tained in the cementum, and situated principally upon the outer surface
of the dentine, and a doubt was expressed whether these were to be
regarded as forming a part of the structure of the cementum, or
whether they constituted a distinct organization.
The cementum is particularly liable to an increased and abnormal
development constituting exostosis.
It would thus appear, on the one hand, that the cementum and
dentine are but modifications of each other, and also of one and the
* See Lecture V.
344 THE SOLIDS.
same tissue, the osseous; while, on the other, it is evident that the
enamel is a modification of the epithelium.
Mr. Nasmyth describes the cementum as passing over the crown
of the tooth and surface of the enamel, in a thin layer composed of
hexagonal cells and fibres; this layer exists only on the surface of
the enamel of the young teeth of the human subject, and it is not
composed of dentine, but consists of either a few of the unelongated
cells of the enamel pulp, or, as Mr. Tomes considers, of the inner
surface of the sac of the tooth.
Nature of Caries of the Teeth.
Various opinions have been entertained in reference to the nature
of the peculiar decay denominated caries, to which the teeth are
so liable. Some have supposed that it is a vital process resulting
from inflammation. The fact that dead teeth, that is, teeth which
have been removed from the jaw and are again employed as artificial
teeth, undergo a similar decay to that which affects the living teeth,
proves that it is not essentially a vital action, although it cannot be
questioned but that the condition of vitality and the state of develop-
ment of the teeth must exert a powerful influence over the progress
of the decay. Other observers regard the decay of the teeth as a
purely chemical phenomenon, the earthy matter of the teeth being
removed by the action of free acid in the saliva: this view of its
nature certainly explains many of the circumstances connected with
dental caries, and is supported by the fact already cited, viz: that
dead teeth are susceptible of the change.
Two facts, however, require to be determined before the chemical
theory of the decay of the teeth can be considered to be proved ;
first, that the saliva is in every case of dental caries really acid; and
second, that the portion of the tooth which is subject to the carious
action is really dead : upon both of these points considerable doubts
may be entertained.
For myself, I have long entertained the idea that the real and proxi-
mate cause of the decay of the teeth was to be found in the presence
of some parasitical production, and that the condition of vitality of
the teeth and of the states of the saliva were to be considered merely
as predisposing causes to the affection.
This idea acquires some confirmation from an examination of the
carious matter of a tooth; in it vast quantities of minute threads or
filaments, possibly those of a fungus, are invariably to be discerned,
TEETH. 345
as well as numberless dark granules and irregular masses, bearing in
some cases the aspect of true cells.
The question may be asked, are these threads, granules, and cell-
like masses any thing more than the decomposing elements of the
dentine, in which tissue it is that the chief ravages of the decay
occur ? The answer is, possibly not ; but the surprising numbers of
these filaments and the testimony of Mr. Tomes are opposed to the
idea that they are the remains of the tubes of the dentine. Mr. Tomes
thus writes in his tenth Lecture in reference to the tubes of the
dentine : " A transverse section of carious dentine, rendered soft like
cartilage from the loss of its lime, presents a cribriform appearance.
The tubuli seem enlarged and rather irregular, quite unlike the figure
they present in healthy dentine : this would indicate that the solvent
enters and acts upon the parietes of the tubes previous to affecting
the inter-tubular tissue, and that the parietes of the tubes are there-
fore the first to disappear. I feel quite certain that in the cases I
have examined, and they are numerous, the parietes of the tubuli, so
distinguishable in healthy dentine, have almost, if not wholly, disap-
peared with the removal of the lime."
Nature of Tartar on the Teeth.
Tartar of the teeth consists of phosphate of lime mixed up with
the mucus of the mouth and epithelial scales: it contains also occa-
sionally animalcules and vegetable growths, which find in the animal
matter of the tartar a convenient nidus for their development. The
accumulation of tartar around the necks of the teeth results from an
opposite condition of the saliva to that to which chemists ascribe
dental caries, viz: an alkaline state of it.
TEETH.
[The substance of the teeth being harder than that of bone, thin sections,
which should be made in different directions, must be first cut by means of
a lapidary's wheel charged with emery or diamond-dust. These sections
are then farther reduced in the same manner as those of bone — first, by the
files, next by the hones, and lastly polished. Like bone, they may be
either mounted in balsam or dry ; the latter method is. preferable when the
section is sufficiently thin to show well the structure.]
34G
THE SOLIDS.
ART. XVII. — CELLULAR OR FIBROUS TISSUE.
The truth of the scientific dictum, that every living thing proceeds
from a germ or ovum, is now generally admitted, and so also it may
be said that each portion of the fabric of such living entity takes its
origin in a cell, the early and embryonic condition of every organ
and structure being reducible to that of a cell.
It was not, however, this consideration that induced the older
anatomists to apply the term cellular to the tissue about to be
described, they having but little knowledge of the structure of the
elementary cell, or of its universal presence.
They were led to denominate the tissue, into the description of
which we are about to enter, cellular, in consequence of observing
the areolae or spaces left between the fibres of which it is composed,
and which they erroneously considered to be cells. The cellular
tissue, then, though like all other tissues, taking its origin in cells,
inasmuch as in its fully developed state it consists of fibres, would be
more accurately denominated the fibrous tissue, as indeed by many
modern anatomists it really is : the term cellular tissue is, however,
one of so ancient a date, and one, moreover, in such general use, and
so well understood, that it seems to be scarcely advisable to abandon
the use of it altogether.
The cellular or fibrous tissue, however, as ordinarily encountered,
is constituted not of a single description of fibre, but consists of two
kinds intermingled in different proportions, and each of which is
possessed of distinct characters and properties.
The most remarkable difference between the two descriptions of
fibrous tissue is, that the one is white and inelastic, and the other
yellow and elastic : each of these will be described under different
heads, and the former before the latter.
INELASTIC OR WHITE CELLULAR OR FIBROUS TISSUE.
Tendons, Ligaments, Membranes, fyc.
The inelastic fibrous tissue is very generally distributed throughout
the body: it constitutes the principal portion of tendons, ligaments,
and fasciae : of the fibrous membranes, the dura mater, pericardium,
CELLULAR OR FIBROUS TISSUE. 347
periosteum, perichondrium, tunica albuginea of the testicle, and
sclerotic coat of the eye; also, of the serous, synovial and mucous
membranes, as well as of the skin, and it forms likewise the principal
constituent of the loose cellular tissue which is so abundantly devel-
oped throughout every tissue and organ of the body, but which is
invariably present in large quantities wherever motion is necessary,
as in the axilla, between the fasciculi of muscles, and in the course
of the vessels.
When endowed with a distinct form, as in the case of the tendons,
it may be called morphous inelastic cellular tissue, and when it has
no circumscribed shape, the term amorphous may be applied to it:
when constituting membrane, it exists in the state of condensed
fibrous tissue ; and when it merely binds organs together, or allows of
the motion of parts, it maybe called loose or reticular cellular tissue.
There is, however, a form of the inelastic fibrous tissue which
requires not merely a separate name, but a distinct notice. This
form is met with in the great omentum, and consists in the fact of
spaces of irregular size and form being left between the fibres, and
hence it may be termed areolar cellular tissue. The best examples
of it are met with in the omenta of children and lean persons, which
contain but little fat. (See Plate XL. fig. 4.)
The inelastic cellular tissue is made up of innumerable unbranched
threads or fibres of equal calibre, of great tenuity, which appear
white to the unassisted sight, but of a yellow colour when viewed
under the microscope, and which have a great disposition to assume
a waved or zigzag arrangement, the folds formed being comparable
to those in which a loose skein of silk is often observed to fall. (See
Plate XXXIX. fig. 6.)
When dried, the inelastic cellular tissue assumes the transparent
appearance and consistence of horn; in water, the fibres swell up
somewhat, become opaque and white, but still preserve their form :
in acetic acid, they swell up greatly, become indefinable, soft and
gelatinous: the addition of a mineral acid will, however, bring the
fibres again into view. A
The remarkable effect of acetic acid on the inelastic fibrous tissue,
has suggested the idea to Mr. Bowman that "it is rather a mass with
longitudinal parallel streaks (many of which are creasings), and which
has a tendency to slit up almost ad infinitum in the longitudinal
direction."
There are several considerations which may be urged in disproof
348 THE SOLIDS.
of this view; the first is, the mode of development belonging to this
tissue ; the second, the fact that the fibres are all of nearly an equal
diameter; and the third is, that the tissue still retains its fibrous
constitution even after the application of acetic acid.
The white fibrous tissue is employed wherever a strong and
inelastic material occupying but little space is required.
A degree of elasticity not unfrequently appears to belong to this
tissue; but this is rather apparent than real, and depends upon the
extent of its admixture with the next form of fibrous or cellular
tissue to be described, viz: the elastic. (Plate XXXIX. jig. 1)
ELASTIC CELLULAR OR FIBROUS TISSUE.
The elastic cellular or yellow fibrous tissue is distinguished from
the inelastic form by its branched filaments, the diameter of which is
unequal, its elasticity, its deeper colour, and the absence of any
appreciable effect on the addition of acetic acid. (See Plate XL. jig. 1.)
Like the inelastic fibrous tissue, it rarely occurs in an unmixed
form, being mostly intermingled with it in variable proportions : thus,
it is encountered in tendons, ligaments, and, indeed, in all forms and
conditions of the inelastic cellular tissue; it constitutes the principal
portion of the ligamenta sub-flava and nuchas, of the transverse fascia
of the abdomen, of the crico-thyroid and thyro-hyoid membranes, of
the chordae vocales, of the internal lateral ligament of the lower jaw,
of the stylo-hyoid ligaments, of the middle coat of the arteries, and
of the membrane uniting the rings of the trachea and its ramifications.
It is also met with in considerable quantities beneath the mucous
membrane of the oesophagus, at the base of the epiglottis, in main-
taining which in the erect position it is probably mainly instrumental,
in the lungs and in the integuments of the penis.
The elastic cellular tissue presents some differences of appearance
and structure, in certain of the situations in which it is encountered :
thus, in the tendons and in the smaller blood-vessels (Plate XL. jigs.
1, 2, 3. 5) the fibres are very slender, appear to be but little branched,
and contain at intervals nuclei in the same manner as do the fibres
of unstriped muscles; in the reticular cellular tissue again, they are
slender, unbranched, and without nuclei (see Plate XXXIX. jig. 7) ;
in the ligamenta flava and nucha?, in the crico-thyroid and thyro-hyoid
membranes, the fibres are thick, much branched, curled, and inter-
woven, but they do not present nuclei (see Plate XL. jig. 1) ; in the
larger arteries, the fibres are slender, and are united together so as to
CELLULAR OR FIBROUS TISSUE. 3 19
form areolae (see Plate XL. fig. 2), while in the smaller blood-vessels
they are distinctly nucleated, as already observed.
There is little doubt but that the several forms of elastic tissue just
described do really represent different stages and states of the same
structure ; and it will be observed, that some of them, and especially
that of the small blood-vessels, approach very closely in structure
and appearance to that of unstriped muscular fibre : the fibres of the
former differ, however, in being sparingly branched, and in their
more slender diameter.
It is not easy, without the addition of reagents, to distinguish the
two forms of fibrous or cellular tissue from each other when mixed
together: nevertheless, when the two are well separated, the elastic
fibres may be frequently singled out from the inelastic, in consequence
of their presenting a darker and stronger outline, as well as of their
following a more curled and tortuous course. (See Plate XXXIX.
fig. 7.) Acetic acid applied to a portion of mixed cellular tissue, at
once allows the elastic fibres to be clearly seen, rendering the inelastic
fibres transparent, and almost invisible.
There are several parts of the human organization described by
modern minute anatomists and physiologists as being in part com-
posed of unstriped muscular fibre; these are the skin, dartos, nipple,
clitoris, penis, the ducts of the larger glands, as the ductus communis
choledochus, the ureters, and vasa deferentia. Now, I find that all
these parts, which I have examined with care, owe their contractility,
and their power of erection, to the presence of the nucleated form of
the elastic tissue which has been described as existing in tendons and
the smaller blood-vessels, and not to any form of muscular fibre; and
further, that in the majority of them, and especially in the dartos,
penis, clitoris, and nipple, this elastic tissue is confined almost entirely
to the blood-vessels, the walls of which it constitutes : this fact may
be readily ascertained in the instance of the dartos by taking a small
fragment of that membrane when in a fresh condition, and having
spread it out on the surface of a piece of glass without the addition
of any fluid, then submitting it to the microscope, when the number,
size, and course of the blood-vessels may be traced, and the disposition
of the intervening fibrous inelastic tissue recognised: in the recent
state, however, the vessels are filled with blood, the presence of which
prevents the satisfactory detection of the elastic constituent of the
blood-vessels : if now, however, acetic acid be applied to the fragment
of membrane thus spread out, the inelastic fibrous tissue will become
350 THE SOLIDS.
indistinct, the red blood corpuscles contained in the vessels will be
dissolved, and the tissue of the blood-vessels clearly brought out.
(Plate XLIII. fig. 3.)
The extent of contraction of which the dartos is susceptible is very-
great, and the act of contraction must of course exert a very powerful
influence over the circulation of the blood in its vessels. In the
contracted state of this membrane, the slender fibres of the elastic
tissue, as well as their nuclei, are frequently curled up in a spiral
manner, an arrangement by which any amount of shortening may be
secured.
The contraction of the tissue of the dartos, and indeed of all elastic
tissue, is evidently not a physical, but a vital act: this is shown by
the relaxation and contraction which it experiences in sympathy
with the condition of the vital powers, as well as with any causes, as
heat and cold, which affect these powers.
The corpora cavernosa penis and corpos spongiosum urethrae are
almost entirely composed of blood-vessels, and the peculiarity of
these parts consists in the large size of the vessels, and in their
repeated inosculation. (Plate XLIII. j%. 4.)
In the lungs, the blood-vessels are so numerous, that they, in this
case, also constitute the principal portion of the fabric of these
organs: — this may be beautifully seen in the lungs of the lower
reptiles, as the triton and frog.
Henle has described a peculiar arrangement of the fibres of elastic
tissue. "I have already said," he remarks, "that the fibres of the
cellular tissue are for the most part united into a number more or less
considerable, and thus form flattened bands of different thickness.
These bands unite in their turn to produce others larger, or even
membranes, and thus, sometimes they apply themselves parallelly to
each other ; at others, they cross each other in the most varied
directions. When the cellular tissue fills the interstices of organs
under the form of a soft mass, easy to displace, and extensible, the
bundles may be perceived without the least preparation, seeing that
they cross and interlace in all directions, and that even to the naked
eye, they represent a net-work of delicate fibres. The size of the
bundles, which I call primitive bundles, or after their origin, the
fibres of the cells of cellular tissue vary from the 0'003 to the 0 006
of a line. The majority of the primitive bundles are deprived of
special envelope: the fibres may easily be detached, the one from the
other, and separate, when one bends a bundle strongly. But in many
CELLULAR OR FIBROUS TISSUE. 351
situations they are interlaced, and held together by filaments, which
differ from the fibres of cellular tissue by their chemical and micro-
scopical peculiarities, while in certain respects they approach the
fibres of elastic tissue; of which we shall give a description further on.
They are almost still finer than the fibres of cellular tissue, quite flat
and homogeneous, but with outlines much more obscure, and they are
distinguished, above all, by the considerable folds, which they describe
when they are in a state of separation. In order to recognise them,
it is necessary to place the cellular tissue in contact with acetic acid :
in this acid the bundles of cellular tissue become transparent, swell,
and cease to appear fibrous, while the filaments which envelope them
undergo no change. In this manner it happens that a bundle, which
appears to be composed of the ordinary interlaced fibres of cellular
tissue, comports itself after having been treated with acetic acid, as a
transparent cylinder divided by contractions often very regular, and
which one soon observes to be caused by a filament which runs
spirally around the bundle; or also by separated rings placed at a
greater or less distance from each other I have rarely succeeded in
reducing the turns to a single filament, and I am obliged in conse-
quence to leave undecided the question, whether it does not sometimes
happen that many filaments are rolled spirally around a bundle. The
formations which I have described show themselves in no part in a
more beautiful manner than in the delicate and firm cellular tissue,
which is situated at the base of the brain beneath the arachnoid,
between the vascular trunks and the nerves, and which becomes
distended into isolated filaments, on extension, as, for example, in any
part of the circle of Willis. There I have never sought the spiral
filaments in vain; nevertheless, analogous bundles, encircled with
spirals, may be seen also upon other parts of the economy, in serous
membranes, in the sub-cutaneous cellular tissue, in the skin, and even
in the tendons."*
It appears to me that Henle has misunderstood the structure, and
consequently the nature of the formations noticed by him: there can
A be little doubt but that these, in place of being bundles of filaments
composed of inelastic fibrous tissue encfrcled with a spiral coil of
elastic tissue, are in reality hollow cylinders, vessels in fact in progress
of formation, consisting of, in the stage described by the German
physiologist, an inner transparent and apparently structureless tunic,
enclosed in a coil of elastic fibrous tissue.
* Anal. Gen. vol. i. pp. 377, 378.
352 THE SOLIDS.
The correctness of this view is established by the very convincing
fact, that the tubular formation in the condition just described may
be traced up to the state of perfect blood-vessels, some of which may
also now and then be seen dividing into branches, and containing,
moreover, blood corpuscles. Several of the stages of the development
of these vessels are seen in Plate XL.fig. 3.
DEVELOPMENT OF CELLULAR TISSUE.
Exact observations are still required on the subject of the develop-
ment of both the elastic and the inelastic forms of the cellular or
fibrous tissue, and especially of that of the latter form. Schwann and
all other observers after him have described the cellular tissue as
taking its origin in cells of an elongated form, from the extremities of
which fibres, mostly branched, proceed, the cells themselves ultimately
becoming absorbed : microscopists, however, have not as yet attempted
to point out the differences which doubtless exist in the development
of the two forms of cellular tissue, but have for the most part con-
tented themselves with the above general description.
It appears to me that the observations already made on the devel-
opment of the cellular tissue apply only to the yellow or elastic kind ;
and to this conclusion I am led by the fact that observers describe
the elongated nuclei as giving origin to branched filaments; and we
know that the fibres of the inelastic fibrous tissue are simple, and not
branched.
According to my observations, both forms of cellular tissue origin-
ate in cells.
The cells of the white fibrous tissue exist first as rounded nuclei,
around which the cell wall gradually makes its appearance, and these
cells when fully formed are large, granular, elongated, fusiform, and
from each extremity at length proceeds a single unbranched thread,
which gradually becomes extended into a filament or fibre, which is
produced by the growth and extension of the cell wall itself, and the
extremity of which unites for the production of an elongated thread
with that proceeding from the other cells placed above and below it :
finally, the process terminates by the absorption of the nuclei. (See
Plate XLIII.jffe. 2.)
The cells of the yellow fibrous tissue also exist, at 'first as nuclei,
then as fusiform cells, but. differ from those of the white fibrous tissue
in the subsequent steps of their development, in that the cells are dis-
posed in lines, each fibre being formed, as is the case with the unstriped
DEVELOPMENT OF CELLULAR TISSUE. 353
muscular fibre, by the union of the filaments, proceeding from each
series of linearly disposed cells, and in that the filaments proceeding
from the cells are very frequently branched. (See Plate XXXIX. figs
1, 2. Plate XL. figs. 3. 5.)
The above-described mode of development may be followed out in
longitudinal and cross sections of tendon treated with acetic acid; also,
in the smaller vessels of the pia mater, and in those placed in the
mixed cellular tissue which separates the different striped muscular
fasciculi: we thus perceive, that in the case of the yellow fibrous
tissue, many nuclei are required to form a single filament ; and further,
that there is a strong analogy in the mode of its development with
that of muscular fibre, as also in the physical properties of the two
tissues.
In the fibrillation of the fibrin of the blood we have an example of
the formation of filaments independently of any development from
cells, and at one time I conceived that the fibres of the white fibrous
tissue might possibly originate in a similar manner.
23
354 THE SOLIDS.
ART. XVIII. — MUSCLE.
Few of the animal tissues have been more extensively examined
than the muscular: the multiplied observations made on its structure
have, however, led neither to that uniformity of opinion respecting it,
nor, indeed, to that accurate knowledge of its minute anatomy, which
might have been anticipated; of the truth of this position, evidence
will be shortly adduced.
Muscles admit of division into the voluntary, or those which are
under the control of the will, and the involuntary, or those of which
the action takes place independently of the will; the former consist
of the muscles of animal life — those, for example, of locomotion — and
the latter embrace those of organic life, as the muscles of the aliment-
ary canal (the sphincters of the oesophagus and anus excepted, which
are to a certain extent voluntary), the heart, the uterus, the bladder, &c.
It will be observed, that the involuntary muscles, or those of
organic life, usually encircle the hollow viscera; there are some other
situations, however, in which involuntary muscular fibres are met
with, as in the trachea and its bronchial ramifications, the iris, the
sarcolemma, and, according to some observers, as Bowman, they are
also encountered in the dartos and covering the excretory ducts of
the larger glands, as the ductus communis choledochus, the ureters,
and vasa deferentia; and it is with them a matter of question how
far the contractility of the skin, and the erection of the penis, clitoris
and nipple, may be dependent upon the presence of involuntary mus-
cular fibrillae. In the preceding article I have, however, shown that
the contractility of these parts depends upon the presence of a nucle-
ated form of elastic tissue, allied to unstriped muscular fibre in many
of its properties, but yet distinct therefrom.
Corresponding with the division of muscles into voluntary and invol-
untary, there exist differences of structure: thus, the muscles under
the control of the will are all striped, while those which are not under
its influence are unstriped. To this rule, however, one remarkable
exception may be mentioned, viz: the muscles of the heart, the action
of which is to a great extent involuntary, and which are yet striped :
this exception is rather apparent than real, as will be seen hereafter.
MUSCLE. 355
STRUCTURE OF MUSCLE.
A striped muscle is made up of a number of unbranched fibres, each
of which is included in a distinct sheath, the sarcolemma, and consists
of a number of threads or fibrillae : the fibres again are collected into
sets or bundles called lacerti; these are held together, and yet separ-
ated by a mixed form of cellular tissue, which also contains fat vesicles,
blood-vessels and nerves.
An unstriped muscle consists of fibrillae, intermingled with fibrous
tissue: these do not form fibres, and consequently there is no
sarcolemma.
Between striped and unstriped muscle there is no essential or spe-
cific structural difference: the one is not to be regarded as typically
distinct from the other, but both should rather be considered as differ-
ent conditions in the development of one and the same tissue. Of
this position, evidence will be hereafter adduced.
According to the above view, muscular fibre presents two grand
stages of development; the first of which is represented by the
unstriped fibrilla, and the second by the striped muscular fibre.
We shall first describe the structure of the unstriped muscular
fibrilla, because it represents an earlier condition of development than
the striped.
Structure of Unstriped Muscular Fibrillce. — Unstriped muscles
consist of fibrillae which are unbranched, rather broad, somewhat flat,
and which contain, imbedded in their substance, elongated and gran-
ular nuclei. (See Plate X.hl. fig. 2.)
The fibrillae usually run parallel to each other, and form thin layers
and fasciculi, which are separated from each other by cellular tissue,
and frequently interlace.
The nuclei are sometimes imbedded in the substance of the fibrillae,
without at the same time increasing their diameter: at others, they
render the fibrillae ventricose from their great size ; and again, in other
cases, they protrude from their sides. (See Plate Uhl.fig. 2.) They
are best seen after the addition of acetic acid.
Unstriped muscles are doubtless freely supplied with blood-vessels
and with nerves.
The unstriped muscle is called into action with greater difficulty
than the striped; its action is also slower, and of a peculiar kind, giv-
ing rise to the vermicular and peristaltic motion, seen especially in
the intestines.
356 THE SOLIDS.
This slower and less energetic action results from its lower degree
of organization.
The muscular structure of the heart, the action of which is to a
considerable extent involuntary, requires a special description. The
muscular tissue of this organ has been usually supposed to constitute
an exception in its structure to that of other involuntary muscles, and
that while it performed the office of an involuntary muscle, it yet
possessed the structure of a voluntary muscle, its fibres being striped.
Mr. Bowman, one of the very best authorities on the structure of
the muscular fibre, gives the following description of the tissue of the
heart : " The cross stripes on the fibres of the heart are not usually
so regular or distinct as in those of the voluntary muscles. They are
often interrupted, or even not visible at all. In some of the lower
animals their sarcous elements never form transverse stripes. These
fibres are usually smaller than the average diameter of those of the
voluntary muscles of the same subject by two-thirds, as stated by Mr.
Skey."*
This description is very imperfect, and in some respects, according
to my observations, incorrect. Thus, the muscular substance of the
heart does not form fibres at all, but consists simply of fibrillae, which
agree in every respect with those of other involuntary muscles, save
in their transverse striation: thus they have the same considerable
diameter: they are, in like manner, abundantly nucleated (see Plate
XLI. fig. 3), and they have the same arrangement, interlacing with
each other, and not forming fibres included in a sarcolemma, as is the
case with the voluntary muscular tissue. The transverse striae, too,
have not the deep and permanent character belonging to the fibrillas
of ordinary striped muscle, as is evinced by the fact that acetic acid
effaces all vestige of striation.
It thus appears that the muscles of the heart agree in structure
much more closely with that of other involuntary muscles, which is
contrary to what is generally supposed, than they do with that of the
voluntary muscles.
Thus, then, the structure and the function of the muscles of the
heart are in accordance, and not in antagonism, as is usually con-
ceived, the single point of difference between its fibrillae and those of
other involuntary muscles consisting in the feeble transverse striation,
the presence of which evinces a somewhat higher degree of develop-
ment, as well as a greater power of contractility.
* Physiological Anatomy, p. 161.
MUSCLE
357
St 'ructure of Striped Muscular Fibre. — The striped muscle consists
of fibres: each of these is included in a distinct envelope, termed
Sarcolemma, and is made up of a number of lesser fibres or fibrillae.
(See Plate XLII. fig. 1.)
The fibres vary very considerably in size, not merely in different
animals, but also according to the age of an animal, and even in a
single bundle of the same animal, some of them being three or four
times larger than others, and the smaller being usually adherent to
the larger fibres; a fact which has reference to the development of
muscular tissue, and which will be explained when we arrive at the
consideration of that portion of our subject. (See Plate XLII. fig A)
The difference in the size of the fibres according to age is very
remarkable, those of the foetus being several times smaller than the
fibres of the adult. (See Plate XLIL fig. 1, and Plate XLIII. fig. 1.)
They differ also to a very considerable extent in form as well as
magnitude: thus, in a cross-section and in a recent state, they are
seen to be more or less angular and compressed, but still preserving,
in most cases, much of the character of cylinders. In the dry con-
dition, this angularity is greatly increased, and to this state of the
fibres the representations hitherto given chiefly refer. (See Plate
XLII. fig. 5.)
The fibres, both great and small, are, as already observed, arranged
in bundles or lacerti, of variable size; those of the same bundle run
parallel to each other, and the different bundles are separated, and yet
held together by mixed fibrous tissue.
Examined with a moderate power of the microscope, each fibre
is seen to exhibit numerous transverse striae, which are placed at
tolerably regular distances from each other: some fibres, also, and
especially such as have been preserved in spirit, present numerous
fainter longitudinal striae.
When viewed with a somewhat higher object-glass, and when each
fibre has been torn into pieces by needles, its entire bulk will be seen
to be made up of a number of slender threads of equal diameter,
which present a distinct transverse striation.
It was formerly very generally supposed that the transverse lines
on the striped muscular fibre were produced by a filament which
wound spirally around it : this notion is, doubtless, erroneous, as
indeed it is now generally allowed to be.
It has been observed, that the fibrillae are themselves marked with
transverse striae : now, it is not difficult to convince one's self that the
358 THE SOLIDS.
striation of the fibre is produced by the striae of the fibrillar, the striae
of one fibrilla corresponding with that of another, and thus giving rise
to a line which extends entirely across the diameter of the fibre.
The correctness of this explanation might have been easily inferred
from a knowledge of the composition of the striated muscular fibre
of banded fibrillae, and from the aspect of the transverse line itself,
which, when examined with a high power of the microscope, does
not present the appearance of an uninterrupted and continuous line,
such as would be produced by the winding of a filament around it,
but rather of a line formed by the apposition of a series of dots or
shorter lines ; in which manner, indeed, it is that the striation of the
fibre is really produced, as we have seen.
The fibrillae contained in each fibre are unbranched, of great
tenuity, of nearly equal diameter (see Plate XLII. fig. 1), and their
number varies greatly, amounting in the larger fibres to as many as
fifty or sixty, while in the smaller they may not exceed from one to
five and upwards, according to the breadth of the filament.
The striae present a very uniform and strongly marked character:
the spaces between them are not, however, equal: thus, they are
sometimes rather longer than the diameter of the fibrilla: at other
times, they are shorter, and when the striae are very close, the fibrilla
becomes ventricose or moniliform.
Much difference of opinion prevails as to the nature of the striation
exhibited by the fibrillae. Drs. Sharpey* and Carpenterf incline to
the opinion that each fibrilla consists of a series of particles or cells
cohering in linear series, and that the lines indicate the point of
junction of these ; Mr. Erasmus WilsonJ attributes a still more
complicated structure to the striated fibrilla. He believes that two
kinds of cells exist in each fibrilla; a pair of light cells, separated by
a delicate line, being interposed between each pair of dark ones.
Lastly, Bowman considers that the lines indicate the divisions
between particles, which he denominates "sarcous elements."
My own view of the nature of these lines differs from that of all
the gentlemen named. I consider that the lines in question are
produced by the simple corrugation or wrinkling of the threads at
regular distances : a view, the accuracy of which is all but proved
by a consideration of the development of muscular fibre, and by the
* Quain's Anatomy, 5th edition, vol. ii. p. 168.
f Human Physiology, p. 176.
\ Manual of Anatomy, 3d edition, p. 16.
MUSCLE. 350
action of acetic acid on the fibrillar of the heart, the transverse
markings of which it entirely obliterates.
The fibrillae are, as already stated, included in a sheath, the sarco-
lemma of Bowman, both together constituting the fibre. The sheath
cannot at all times be seen: it may, however, frequently be so, and
especially when the fibrillae have been torn across, the sheath at the
same time not having been divided, its greater elasticity enabling it
to resist the force which was sufficient to rupture the muscular
fibrillae. It is in such cases that the best view of this membrane is
obtained. (See Plate XLU. fig. 1.)
Treated with acetic acid, each fibre discloses most distinctly a
considerable number of elongated and granular nuclei, the outlines
of which are in some cases visible, even without the application of
the acid. (See Plate XLII. fig. 2.)
Of these nuclei, Mr. Bowman remarks: "In the fully-formed fibre,
if it be large, they lie at various depths within it; but if small, they
are at or near the surface. They are oval and flat, and of so little
substance, that though many times larger than the sarcous elements,
and lying among them, they do not interfere with their mutual apposi-
tion and union." "It is doubtful whether the identical corpuscles,
originally present, remain through life, or whether successive crops
advance and decay during the progress of growth and nutrition: but
it is certain that as development proceeds, fresh corpuscles are depos-
ited, since their absolute number is far greater in the adult than in
the foetus, while their number relatively to the bulk of the fibre at
these two epochs remains nearly the same."*
The above description is in part only correct. Thus I find, first,
that the nuclei are invariably situated on the external surface of the
fibre, the majority within the sheath, and either adherent to this, or to
the exterior fibrillae, some also being placed on the outer surface of
the sarcolemma; facts which throw much light upon the development
of the muscular fibre; secondly, that the nuclei are not usually free
nuclei, but are contained in most cases in filaments in every way
similar to those of unstriped muscle, and with which they are identical.
Were the nuclei really scattered throughout the substance of a
muscular fibre, they would infallibly destroy the parallelism of the
striae, and greatly interfere with its contractile power.
The interpretation to be given of the location of the nuclei and
fibres of unstriped muscle in the situations indicated, will be explained
* Physiological Anatomy, vol. i. pp. 158, 159.
360
THE SOLIDS.
when the subject of the development of muscular fibre is considered ;
at the same time, also, the point raised by Mr. Bowman, as to the
persistence of the nuclei, will be. discussed.
The fibres of the upper part of the oesophagus are striped, while those
of the lower half are unstriped. It has been considered a matter of
uncertainty whether the two pass by insensible gradations of structure
into each other, or whether they terminate abruptly. I believe, after
careful examination, that the latter supposition is the correct one.
With a few remarks upon the peculiar views entertained by Mr.
Bowman, in reference to the structure of the striated muscular fibre,
the discussion of the structure of muscle may be brought to a
conclusion.
"It was customary," writes Mr. Bowman,* "both before and since
his time (the time of Fontana), as at the present day, to regard the
fibre as a bundle of smaller ones, whence the term primitive fasci-
culus, first given to it by him, and adopted by Muller; but this view
of the subject is imperfect.-' The fibre always presents, upon and
within it, longitudinal dark lines, along which it will generally split
up into fibrillae ; but it is by a fracture alone that such fibrillae are
obtained. They do not exist as such in the fibre. And further, it
occasionally happens that no disposition whatever is shown to the
longitudinal cleavage; but that, on the contrary, violence causes a
separation along the transverse dark lines, which always intersect the
fibre in a plane perpendicular to its axis. By such cleavage, discs,
and not fibrillae, are obtained, and this cleavage is just as natural,
though less frequent, than the former. Hence, it is as proper to say
that the fibre is a pile of discs, as that it is a bundle of fibrillae : but, in
fact, it is neither the one nor the other, but a mass in whose structure
there is an intimation of the existence of both, and a tendency to
cleave in the two directions. If there was a general disintegration
along all the lines in both directions, there would result a series of
particles, which may be termed primitive particles, or sarcous
elements, the union of which constitutes the mass of the fibre.
These elementary particles are arranged and united together in
two directions. All the resulting discs, as well as fibrillae, are equal
to one another in size, and contain an equal number of particles.
The same particles compose both. To detach an entire fibrilla, is to
abstract a particle of every disc, and vice versa. The width of the
* Physiological Anatomy, vol. i. pp. 151, 152.
MUSCLE. 361
fibre is therefore uniform, and is equal to the diameter of any one of
its fibrillae, and is liable to the greatest variety."
This view of the structure of the. striated muscular fibre is inge-
niously conceived and well expressed; nevertheless, it can be shown,
I think, notwithstanding its ingenuity, to be incorrect.
There are two considerations which appear to me to be sufficient
to disprove the view just propounded. The first is, that the rudi-
mentary muscular fibre consists of one or more threads or fibrillae,
containing imbedded in them a number of elongated nuclei, which,
however, have no correspondence with the transverse markings ; and
the second is, that, while any muscular fibre may at any time be
readily separated into its component fibrillae, the simultaneous trans-
verse cleavage spoken of and figured by Mr. Bowman is an occurrence
of extreme rarity, and one, moreover, of which I have never been able
to perceive the slightest trace in any muscular fibre which has fallen
under my notice.
It would thus appear that the older view is the correct one, and
that the striped muscular fibre is made up, as already described, of a
variable number of fibrillae enclosed in a tubular sheath.*
Blood Vessels of Muscles. — Muscles are copiously supplied with
blood-vessels; the larger vessels are contained in the cellular tissue
separating the fascicles or lacerti of the muscles, and which serves to
support and to conduct them ; the smaller vessels or capillaries are
not encircled by cellular tissue, but penetrate between the fibres,
forming numerous capillary loops and meshes, having their long axes
disposed in the direction of the length of the fibres. This arrange-
ment of the capillaries is shown in Plate XLI. fig. 4.
Much of the colour of a muscle arises from the blood enclosed in
the vessels, but not all, a portion of it being contained in the muscular
fibres themselves.
It is evident that the contraction of the fibres exercises much
influence upon the capillary circulation, reducing the calibre of the
capillaries to such an extent as that the blood-corpuscles can pass
through them only in an elongated form.
In the course of the larger vessels, imbedded in the inter-fascicular
cellular tissue, fat corpuscles are often abundantly distributed, as
represented in Plate XLI. fig. 1 .
Nerves of Muscles. — Muscles are also abundantly supplied with
nerves, principally those of locomotion. Burdach has figured and
* See Appendix, page 548.
362 THE SOLIDS.
described the nerves in muscles as forming loops, which either join
other neighbouring loops or else return into themselves. The figure
and description given by Burdach have been adopted by almost all
succeeding anatomists ; notwithstanding which, I would observe, that
I have never seen the nerves terminating in muscle in the manner
indicated; not, however, that I doubt the fact of their doing so,
because such a mode of termination is common to nerves; but would
simply infer from this, that the loop-like arrangement is neither very
general nor very obvious.
According, then, to the latest physiologists, nerves, strictly speaking,
really have no termination whatever in muscles : an opinion, the
accuracy of which is more than doubtful.
I find that the nerves, after branching in a dichotomous manner,
have a real termination, and that from time to time certain tubules
leave the main trunks, and end in the formation of elongated and
ganglioniform organs situated between the fibres of muscle. (See
Plate XLLJig. 4.)
UNION OF MUSCLE WITH TENDON.
The unstriped muscular fibrilla is rarely, if ever, attached to tendon
or aponeurosis : the striped fibre, on the contrary, is almost con-
stantly so.
Two errors have prevailed in reference to the union of the striated
muscular fibre with tendon.
The first has reference to the form of the extremity of the fibre in
connexion with the tendon; the second to the precise mode of junc-
tion between the two.
Thus, most observers have described and figured the fibre as
terminating in a conical point, from which the fibres of the fibrous
tissue of the tendon proceed in a straight line.
This description is contrary to fact, both as respects the form of
the fibre and its mode of union with the tendon: muscular fibre is
rarely, if ever, inserted vertically into a tendon or aponeurosis ; but in
all the instances which have fallen under my observation, the insertion
has been either oblique or occasionally at right angles with the tendon;
the extremity of the fibre being in the one case also oblique, and in
the other truncate : this termination is the very opposite of that
usually attributed to it. Let us next see in what way the two struc-
tures are united. In no one instance have I ever seen the fibres of
the fibrous tissue of the tendon unite themselves directly with the
muscular fibre : on the contrary, the mode of junction has always
MUSCLE. 3G3
been effected in the following manner: — the sheath of each fibre is
prolonged upon the surface of the tendon where the union is oblique,
and certain of the fibres of the tendon are extended upon and inter-
lace with the terminal portions of the muscular fibres and their
investing sheaths. (See Plate XLII. fig. 4.)
MUSCULAR CONTRACTION.
Many attempts have been made to determine the exact changes
which the muscular fibre undergoes in its passage to a state of con-
traction; these attempts do not appear to me to be altogether satis-
factory and successful.
The earliest opinion formed, in reference to muscular contraction,
supposed that during contraction the fibres and fibrillae of muscle are
disposed in a zigzag manner, such a disposition of the fibres of course
having the effect of materially shortening the muscle. (Plate XLIII.
fig- 5.)
The advocates of this view seem to have overlooked the fact that
fibres thus disposed, having no fixed or direct points from which to
act, would have their power by such an arrangement rather diminished
than increased: this idea has therefore been justly discarded, and an
account of the nature of muscular contraction, much more closely
approximating to the truth, substituted in its place.
Mr. Bowman, who has written by far the best account of muscular
contraction which has yet appeared, discriminates between passive
and active contraction of muscle : the former he conceives to be a
uniform act, involving and affecting equally the entire mass of the
muscle : the latter, on the other hand, he considers to be a partial act,
implicating, first, a particular part or parts of a fibre ; subsequently
leaving these, and advancing to other and neighbouring parts of the
same fibre.
This view is founded principally upon the experiment detailed
below, made upon a fibre of the claw of a crab, which still retained
its contractility. "In an elementary fibre from the claw, laid out on
glass, and then covered with a wet lamina of mica, the following
phenomena are always to be observed: The ends become first con-
tracted and fixed. Then contractions commence at isolated spots
along the margin of the fibre, which they cause to bulge. At first
they only engage a very limited amount of the mass, spreading into
its interior equally in all directions, and being marked by a close
approximation of the transverse stripes. These contractions pull
364 THE SOLIDS.
upon the remainder of the fibre only in the direction of its length;
so that along its edge the transverse stripes in the intervals are very
much widened and distorted. These contractions are never station-
ary, but oscillate from end to end, relinquishing on the one hand what
they gain on the other. When they are numerous along the same
margin, they interfere most irregularly with one another, dragging
one another as though striving for the mastery, the larger ones con-
tinually overcoming the smaller; then subsiding, as though spent,
stretched by new spots of contraction ; and again, after a short period
of repose, engaged in their turn by some advancing wave. This is
the first stage of the phenomenon. At a subsequent stage, the ends
of the fibre commonly cease to be fixed, in consequence of the inter-
mediate portions, by their contraction, receiving some of the pressure
of the glass. The contractions, therefore, increasing in number and
extent, gradually engage the whole substance of the fibre, which then
is reduced to at least one-third of its original length."*
To this experiment, which I have never been able successfully to
repeat, some exceptions may be taken. Thus, it is known that water
has a powerful and remarkable effect in exciting muscular fibre which
still retains its irritability to contraction, and the nodulated aspect of
the fibre mentioned, may have been due to the fact that the fibre was
not entirely immersed in water (the piece of mica being merely
moistened), but only touched by that fluid at certain intervals, which
most probably corresponded with the bulgings of the fibre referred to.
This explanation is supported by the effect of water on recent mus-
cular fibre, entirely immersed in that liquid. Thus, on the moment
of immersion, the fibres contract greatly in length, increase in a
corresponding proportion in bulk, become irregularly bulged and
nodulated: the transverse lines on the fibres disappear, the longitu-
dinal lines at the same time becoming more strongly marked than
usual. (See Plate XLII. jig. 3.) These several effects are due to
the extraordinary, unequal, and doubtless, also, abnormal contraction
induced by the stimulus of water. Presuming, therefore, that in the
experiment referred to, the phenomena occur in the order described,
yet it would not be safe to adopt the conclusion, from this, that they
represent the several stages of the normal contraction of a muscular
fibre. Again, it might be argued, that the nodular condition described
as belonging to a muscle in a state of active contraction would be
most unfavourable for the full exercise of the power of contraction,
* Physiological Anatomy, pp. 180,181.
MUSCLE. 365
seeing that the nodules of one fibre would necessarily interfere with
those of the contiguous fibres, and thus impede its own as well as
their contraction.
For the above reasons, therefore, I would place but little reliance
upon the experiment quoted, and prefer to adopt an explanation more
simple in its character, and yet entirely sufficient to explain the
condition of a muscle during its state of most active yet entirely
normal contraction.
I conceive that no distinct line of demarcation exists whereby
active and passive muscular contraction can be discriminated: the
two are but different degrees of the same power, and manifest them-
selves by phenomena which differ not in kind, but simply in extent.
If a muscle of the leg of a frog be isolated from its fellows, or if
the tongue of the same animal be extended and pinned to the margins
of an aperture made in a piece of cork, the only change which can be
observed to take place in the muscular fibre, when stimulated to con-
traction, consists in an approximation of its striae, neither waves nor
nodules manifesting themselves in its course.
Again; immersion of muscular fibre, which has almost lost its con-
tractile power in water, will be followed by an approximation of the
striae, and a proportionate increase in the diameter of the filament.
Now, the approximation of the striae is the only visible sign which I
have ever been able to detect in natural muscular contraction ; and it is
amply sufficient to account for the shortening and increase in diameter
which a muscle undergoes during its state of most active contraction.
The distance between the striae in a fibre placed somewhat on the
stretch, as are all muscular fibres in their natural state, and in that
which is in a state of contraction, varies greatly, and is very evident,
the striae in the contracted fibre being often one-third or even one-
half closer together than they are in the fibre in its ordinary state
of tension. The approximation of the striae to the extent just men-'
tioned, presuming the entire length of the fibres to be in a contracted
condition, would reduce the length of the muscle in the same pro-
portion, viz: to the extent of a third or even one-half.
Muscular contraction, then, I would define to be a simple shorten-
ing of the fibres of a muscle, accompanied by an increase in their
breadth ; this shortening in the striped muscular fibre being evinced
by an approximation of the transverse striae, as well as by an increase
in its diameter, while in the unstriped fibre it is manifested solely by
an increase in the thickness of the fibrillae. (Plate XJAI.jig. 3. a, b.)
306 THE SOLIDS.
Whether, in muscular contraction, the whole length of the fibres
of a muscle is engaged, or part only of their length, or whether, during
the continuance of the contraction of a muscle, its fibres remain in a
state of quiescence ; or whether they undergo an alternate contrac-
tion and relaxation, in obedience to the interrupted stimulus derived
through the medium of the nerves, it is not easy to determine with
certainty; nevertheless, it is most probable that where the contraction
is very intense, and long sustained, such an alternation of condition
does exist.
The stiffening of the body, which occurs after death, known by the
terms "rigor mortis," "cadaveric rigidity," is due to muscular con-
traction. This rigidity usually comes on a few hours after death;
and after continuing for a variable time, not exceeding six or seven
days, again disappears. There is much variety, however, in the
exact periods of the advent and departure of the rigidity: it has been
observed to come on latest, attain its greatest intensity, and to last
longest in the bodies of robust persons, who have either died of short
and acute diseases, or who have suffered a violent death. On the
contrary, it has been remarked to set in soonest, and to disappear
earliest, in persons of feeble constitution, and those who have died of
a lingering and exhausting malady.
The' immediate cause of cadaveric rigidity has never yet been
satisfactorily explained. Some have supposed that it depends upon
the coagulation of the blood in the capillaries — an hypothesis scarcely
tenable: others, with more reason, conceive that it proceeds from
the solidification of the fibrin of which muscle is chiefly constituted —
that it is, in fact, a phenomenon precisely analogous to the coagulation
of the fibrin of the blood.
An explanation differing from both of the former has suggested
itself to my mind. I conceive that muscular contraction may possibly
be brought about by the stimulus of the thinner and more watery
parts of the blood, &c, acting on the still irritable muscular fibre,
and which are known to escape from their containing vessels very
shortly after the extinction of life. Of this passage of fluid through
the walls of its receptacle, we have a familiar instance in the case of
the gall-bladder and its contents.
Two other points require to be briefly alluded to, in relation to the
subject of muscular contraction: the first is the muscular sound
heard on applying the ear to a muscle in action, and which has been
MUSCLE. 3G7
likened by Dr. Wollaston* to the distant rumbling of carriage-wheels ;
the second relates to the fact made known by MM. Bequerel and
Breschet, that a muscle during contraction experiences an augment-
ation of the temperature.
DEVELOPMENT OF MUSCLE.
The muscular tissue, like the majority of those which have hitherto
been described, takes its origin in cells.
The term fibre is applicable only to the striped form of muscle, in
which a number of fibrillse are included in an investing sheath common
to them; these striped fibrillse of the striped fibre of voluntary muscles,
are analogous to the unstriped fibrillse of the involuntary muscles.
The process of the development of muscle may be divided into
three stages:
In the first, isolated cells, arranged in linear series, unite to form
the unstriped fibrilla, the nuclei remaining.
This stage appertains to all unstriped muscular fibre.
In the second, the transverse striee or markings appear upon the
fibrillse, the nuclei still remaining.
This stage is permanently exemplified in the muscles of the heart,
temporarily in the voluntary muscles of the foetus, and probably also
in some few other muscles.
In the third period, the fibrillse become very slender, the transverse
markings more defined, and the nuclei altogether disappear.
This condition is represented in all the fully-developed striped
muscles of animal life.
But the striped voluntary muscular fibre, even of the adult, con-
stantly exhibits, and is constantly passing through the three stages
just described ; a fact not generally known. It has been ascertained,
indeed, since the time of Valentin, that the striped muscular fibre of
the foetus originates in cells, and also that cell nuclei are contained
in each fibre of the adult ; but it has not been perceived that the
fibrillse also proceed from cells, and that the stage of muscular devel-
opment, that of unstriped muscular fibre, likewise exists in the volun-
tary muscles of both the foetus and the adult.
It has been supposed, as we have already seen, that the nuclei
which are met with in the striped muscular fibre are scattered
throughout its entire thickness : this has been shown to be erroneous,
and also that the nuclei are situated only on the exterior of each fibre.
* Phil. Trans. 1811.
368 THE SOLIDS.
Now, in every adult striped muscular fibre, we find the nuclei
under the following circumstances : some few of them are in a free
state; others, more numerous, are contained in fibrillae, both striped
and unstriped; of these fibrillae, the majority are on the inside of the
sarcolemma; but some of them are also on its exterior, adhering to
its surface, and constituting a considerable part of its substance:
lastly, internal to these nucleated fibrillae, other fibrillae, which form
the chief bulk of each fibre, exist destitute of nuclei.
With a good defining object-glass many of these unstriped fibres
may be traced for a considerable distance along the fibre, and may
be observed to contain as many as twenty nuclei. .
From these several facts it would thus appear, that striped and
unstriped muscular fibre do not represent distinct types of structure,
but that each is to be regarded as a different stage in the development
of the same. The unstriped muscular fibrilla passes through but one
stage of growth, and then its development becomes permanently
arrested : the fibrillae of the heart, &c, attain a higher degree of
development, the nucleated fibres becoming marked with transverse
striae ; after which their growth permanently ceases : lastly, the
striped fibrillae of the voluntary muscles reach the third and last
period in the development of the muscular tissue, having their nuclei
obliterated, and becoming exceedingly slender.
It would appear, also, that new fibrillae are constantly being devel-
oped, even in the adult muscular fibre.
But certain appearances may be observed which render it extremely
probable that not merely new fibrillae are constantly being developed,
but also that new fibres are continually being formed.
Thus, it is a common thing to meet with unstriped and even striped
fibrillae, which are slightly adherent to the external surface of the
sarcolemma ; again, small muscular fibres attached to the larger
fibres, and consisting of but very few fibrillae, may constantly be
observed. (Plate XLII. fig. 4.)
In the uterus we have a very remarkable example of a periodic
development and subsequent absorption of unstriped muscular fibrillae.
The last point to which reference need be made is, to the doubt
expressed as to "whether the identical corpuscles originally present"
(in the fibre) "remain through life, or whether successive crops
advance and decay during the progress of growth and nutrition."*
This matter is no longer doubtful : the particulars observed in relation
* Loc. eit, pp. 182, 183.
MUSCLE. .}".)
to the development of muscular fibre enable us to give a solution of
the difficult v. Thus, there is no question but that successive crops
of corpuscles or nuclei are continually being formed in both the
striped and the unstriped muscles, and that those in the former are
permanent, while in the latter they are only transitory.
It will be readily perceived that the above-detailed views of the
structure and development of the muscular fibre differ, in very many
important particulars, from those generally entertained. According
to the views of most physiologists, the unstriped muscular fibre is the
analogue of the striped fibre ; while, according to those of the author,
the striped fibrilla is the analogue of the unstriped fibrilla, or "fibre"
of most writers. Dr. Carpenter, in the third edition of the '•'Princi-
ples of Human Physiology," thus clearly gives expression to the
notion that the striped and unstriped muscular fibres are the analogues
of each other. "From the preceding history, it appears that there
is no difference at an early stage of development between the striated
and the non-striated forms of muscular fibre. Both are simple tubes,
containing a granular matter, in which no definite arrangement can
be traced, and presenting enlargements occasioned by the presence
of the nuclei. But while the striated fibre goes on in its develop-
ment, until the fibrilla?, with their alternation of light and dark spaces,
are fully produced, the non-striated retains throughout life its original
embryonic character." The description just quoted, in its application
to the fibrillce of the striped and unstriped muscle, would be most
true, but in its comparison of the unstriped fibrillar with the entire
striped fibre, it is completely at fault.
There is considerable discrepancy between the views entertained
by Bowman and Valentin, and those expressed in this work, in relation
to the development of muscle, as will be evident from the statement of
them by the former gentleman. "The researches of Valentin and
Schwann have shown that a muscle consists, in the earliest stage, of
a mass of nucleated cells, which first arrange themselves in a linear
series, with more or less regularity, and then unite to constitute the
elementary fibres. As this process of the union of the cells is going
forward, a deposit of contractile material gradually takes place within
them, commencing on the inner surface, and advancing towards the
centre, till the whole is solidified. The deposition occurs in granules,
which, as they come into view, are seen to be disposed in the utmost
order, according to the two directions already specified. These
granules or sarcous elements being of the same size as in the perfect
24
370 THE SOLIDS.
muscle, the transverse stripes resulting from their opposition are of
the same width as in the adult; but as they are very few in number,
the fibres which they compose are of corresponding tenuity. From
the very first moment of their formation these granules are parts of a
mass, and not independent of one another; for, as soon as solid matter
is deposited in the cells, faint indications of a regular arrangement in
granules are usually to be met with. It is common for the longitudinal
lines to become well defined before the transverse ones: when both
are become strongly marked, as is always the case at birth, the nuclei
of the cells, which were before visible, disappear from view, being
shrouded by the dark shadows caused by the multitudinous refractions
of the light transmitted through the mass of granules ; but they can
still be shown to exist in the perfect fibre, in all animals, and at all
periods of life, by immersion in a weak acid; which, while it swells
the fibrous material of the granules, and obliterates their intervening
lines, has no action on the nuclei."
According to the views entertained by the author, a striated mus-
cular fibre, in the earliest period of its development, consists of cells
arranged in linear series : these unite together, giving origin to the
fibrilla and not the fibre, and that each fibrilla of a fibre is, in like
manner, developed from cells.
Dr. Sharpey, in the fifth edition of Quain's "Anatomy," makes the
remark, in treating of the subject of the development of muscle, " But
much still remains to be explained by future investigation." The
truth of this remark it is conceived is, in some degree, exemplified in
the foregoing article on muscular fibre.
MUSCLE.
371
MUSCLE.
[To what the striation of muscular fibre is owing, is not yet satisfactorily
established. The opinion of Drs. Sharpey and Carpenter, again referred to
in the Appendix, and seemingly adopted by the author, that the striation, or
dark spots on the fibrillse, indicate the cavities of the cells which compose
each fibrilla, is more probably the correct explanation. The junctions of
these cells, according to the same authorities, are further marked by delicate
transverse lines, intermediate between the cells. These lines are readily
seen in the muscular fibre of the pig, with a power of 600 diameters.
That the striation depends on the corrugation of the muscular fibre, a
theory which the author seemed disposed to adopt in his explanation of
Plate XLIIL, fig. 6, is not probable. The striations are too regular to result
from such cause.
Professor Kolliker has ascertained that non-striated muscular fibre more
generally enters into the structure of different organs, than was usually
believed. His researches on this subject have been very laborious, and an
abstract of the results obtained by him has been published in the eleventh
number of the "British and Foreign Medico-Chirugical Review," for July
1850. This abstract is so clear and concise, and affords such assistance to
the student, that it is here inserted.
ON A NEW FORM OF SMOOTH OR NON-STRIATED MUSCULAR FIBRE.
BY PROFESSOR KOLLIKER.
"Kolliker describes the smooth muscles as composed of short, isolated fibres,
each containing a nucleus. He calls them muscular or contractile fibre-cells, and
gives three varieties:
1. "Short, round, spindle-shaped, or rectangular plates, like those of epithelium,
0-01"' long, and 0-006"' broad.
2. " Long plates of irregular rectangular, spindle or club-like shape, with fringed
edges, 0-02'" long, and 0-001'" broad.
3. " Narrow, spindle-shaped, round, or flat fibre, with fine ends, which are either
straight or wavy, 0-02'", or even 0-25'" long, and 0-002'" to 0'01'" broad.
" The first and second of these forms are only to be found in the walls of vessels ;
the first may be mistaken for the cells of epithelium.
"These muscular fibre-cells are composed of soft, light yellow substance, which
swells in water and acetic acid, in which last it becomes of a paler colour. There is
no appreciable difference between the outer and inner parts, though in acetic acid it
would seem as if each fibre-cell had a delicate covering. Their substance is homo-
geneous, with longitudinal stripes ; and they often contain small pale granules,
sometimes yellow globules of fat. Each fibre-cell has without exception a pale
nucleus, sometimes only perceptible in acetic acid. Its form is peculiar, being like a
small staff rounded at each end. The substance of the nucleus is homogeneous;
its length is 0-006'" —0-004'", its breadth 0-0008" —0-00013'". The muscular
fibre-cells lying side by side, or end to end, form the smooth muscles as they appear
to the naked eye. They may be divided into:
£72 THE SOLIDS.
1. "Purely smooth muscles containing no other tissue; such are those of the
nipple, corium, of the interior of the eye, of the intestines, of the perspiratory glands
of the axilla, of the cerumen glands ot the ear, of the bladder, of the prostate, of the
vagina, of the small arteries, of the veins and lymphatics.
2. "Mixed smooth muscles, which contain, besides the muscular fibre-cells, cellu-
lar tissue, nuclear fibre, and elastic fibre: such are the trabecula? of the spleen and
corpora cavernosa of both sexes. They are also found in the tunica dartos, gall-
ducts, the fibres of the trigonum vesicae, the circular fibres of the larger arteries and
veins, the long and transverse fibres of the prostata, urethra, Fallopian tubes, and of
the womb: they change by imperceptible transitions into the first form; this is the
case in the trachea, bronchi, urethra, the inner muscular layer of the testicles,
seminal ducts, &c.
"Kolliker says, that he has found smooth muscles in the skin to a far greater
extent than is generally supposed. In the sub-cutaneous cellular membrane of the
scrotum, penis (prepuce), and the anterior portion of the perineum, they are well
developed. The greater number seems to exist in the tunica dartos; in the peri-
neum and prepuce there are fewer. In the tunica dartos they form a muscular coat
resembling, on a small scale, the tissue of the bladder. In the nipple and areola
(especially in the female), the smooth muscles are strongly developed, somewhat
resembling those of the tunica dartos, but having no fibrous covering. In the areola,
up to the base of the nipple, they are arranged in circular order; in the nipple they
are circular and vertical, the ducts passing between them. Some lie in the corium,
and form the corpus reticulare; others belong to the sub-cutaneous tissue. Smooth
muscles are also found in every part of the body covered with hair, in the hair-bulb,
and in the upper portion of the corium. In the parts not covered with hair, such as
the palm of the hand, the smooth muscles are wanting. One or two bundles of
muscular fibre encircle each hair-bulb or sebaceous gland. Kolliker remarks, that
the tensor choroidese does not insert itself into the processus ciliaris, but that it lies
fiat on its anterior surface, and that it arises from the canalis schlemmii. The
sphincter pupillae, he says, may be easily seen in the eye of the white rabbit, and in
the blue eye in man, on removing the uvea. In man it is \'" broad, and forms the
pupillar edge of the iris. He has also observed a muscular ring near the annulus
iridis minor. The dilator pupillse does not form a continuous membrane, but seems
to consist of isolated bundles of fibres passing between the muscles to insert them-
selves in the edge of the sphincter. He has never seen the anastomosis of these
fibres mentioned by Todd and Bowman. The writer thinks that the elements of all
these muscles are smooth muscular fibre, thougli he admits that he has seldom suc-
ceeded in isolating the muscular fibre-cells in the human body. He does not think
that the M. cochlearis discovered in the ear by Todd and Bowman deserves the name
of a muscle; he is rather disposed to consider it as a ligamentous structure, and calls
it the ligamentum spirale; he looks upon it as a means of attachment for the zonula
membranacea. Remarking that the smooth muscles of the intestines resemble one
another in their histological characters, he points out one peculiarity, viz : that they
present a knotty appearance with ends running out into fine spirals. He thinks that
it is not improbable that the knots are due to a contraction of the fibre. The fibre-
cells of the intestine seem to be striped, as if they were composed of an envelope
and some homogeneous striped contents. No muscular fibre is found among them,
but they are covered and bound together by cellular membrane.
MUSCLE. 373
" The small perspiratory glands seldom possess smooth muscular fibres, although
these are always present in the large perspiratory glands of the axilla, and in the
cerumen glands of the ear.
"Kolliker does not admit the presence of muscular fibre in the lacteal glands.
"In the lungs he finds that the structure of the small and large bronchi is the
same. Outside of the epithelium they present a layer composed of longitudinal
fibres of areolar tissue, and a number of strong, fine, elastic fibres. Then follow one
or more circular layers of smooth muscular fibre, with some nuclear fibre running
transversely ; lastly, a layer of cellular tissue, with nuclear fibre. He never could
find muscular fibre running longitudinally through the bronchi. With respect to the
vesicles of the lungs, he could come to no satisfactory conclusion. Long nuclei are
seen in the walls of the vesicles, but they are not so long and narrow as those of
the smooth muscles, and appear to him to belong to the capillaries. The smooth
muscles of the trachea and bronchi resemble in their elements those of the intestines.
In the ox, the gall-bladder, the ductus cysticus, d. choledocus, and the ducts lying
out of the substance of the liver, present a large amount of muscular fibre of the
smooth species. It is strongly developed in the canals, in which it is so disposed
longitudinally; in the gall-bladder this is not so much the case, a transverse, and
even an oblique layer of the fibres being placed between two longitudinal layers.
In the human body, the muscular structure is very faintly developed in the gall-ducts.
Kolliker could only discover a very delicate layer at all approaching muscular fibre.
In the pancreatic ducts of the human body, no trace of muscular fibre exists. In the
lacrymal apparatus there are no muscular fibres: in the ductus stenonianus none;
the ductus whartonianus has a very faint layer of smooth muscular fibre.
"No part of the internal structure of the kidney shows traces of museular fibre;
it is only in the calices and pelves that it becomes apparent. The muscular fibres
of the pelves and calices are composed of an outer longitudinal coat, and an inner
transversal layer; they are continuations of the same in the urethra, and all partake
of the general characters of smooth muscular fibre. Supposing the disposition of
the muscular fibres of the bladder to be well known, the writer observes that the
trigonum vesicas consists of a pretty strong layer of pale yellow fibres immediately
under the mucous membrane; this is to be considered as an expansion of the
longitudinal fibres of the urethra.
" The canaliculi of the testes have no muscular fibres, but on the inner side of the
interior surface of the tunica vaginalis communis, smooth muscular fibre is evident.
The vas deferens presents a thick layer of smooth muscular fibre, forming an outer
longitudinal, a middle transverse, and an oblique layer directly under the mucous
membrane. The canaliculi of the epididymis present the same conditions of their
walls as the vasa deferentia. Kolliker thinks he has seen some muscular fibres in
the body of the epididymis. The ductus ejaculatorii are formed like the vas defer-
ens ; the seminal vesicles present also the same conditions. Both coverings of the
prostate — that derived from the seminal vesicles, and its own peculiar covering — are
more or less muscular.
" The pars membranacea urethrae possesses but little smooth fibre, compared with
the prostate. Under the mucous membrane (whose cellular tissue is rich in elastic
or nucleus-fibre) there is a layer of longitudinal fibre, mostly composed of fibro-
cellular membrane, containing nuclear fibre and contractile fibre-cells: this layer is
374 THE SOLIDS.
succeeded by another of transverse fibre belonging to the musculus urethralis; it
also contains smooth muscular fibre. In the pars cavernosa urethra the fibres are
but slightly developed; but they are still found at a certain depth.
"The corpora cavernosa may be considered as highly developed muscular
structures, furnished with peculiar blood-vessels, since the smooth muscular fibres
exist in the fibrous septa, even in the glans.
" The inner portions of the uropoietic viscera in the female resemble those of the
male witli regard to their structure. The urethra has, besides the longitudinal
fibres, a transverse layer of smooth muscular fibre. Fallopian tubes have a thick,
middle layer of longitudinal and transverse fibre ; the elements of which are smooth
muscular fibre-cells, with moderate-sized nuclei. The smooth muscular fibre is with
difficulty isolated in the virgin state ; but in the gravid uterus it is seen in great per-
fection. In the fifth month Kolliker saw bundles of red fibre of the smooth muscular
kind, mixed with cellular membrane, without nucleated fibre; the fibre-cells were
spindle-shaped, and very long. As pregnancy advances, no new cells seem to form;
but those already formed increase in size. Sometimes they measure j^" ' -\" ' ',
they are spindle-shaped, and ran out into long, thin tails. After birth, they rapidly
decrease in size. The middle or vascular layer of the uterus is rich in smooth mus-
cular fibre; it differs only from the inner and outer coat, in the fibres crossing each
other in every direction.
" The ligamenta uteri anteriora et posteriora present a red fibrous tissue, enclosed
in the two folds of the peritoneum; in this, smooth muscular fibre maybe traced.
In the ligamenta ovarii very few are found. The writer says he has seen muscular
fibre in the lower portion of the anterior fold of the peritoneum; on the ligamenta
lata these fibres expand between the folds, and he even thinks that they insert them-
selves in the walls of the pelvis. Directly under the mucous membrane of the
vagina, a layer of muscular fibre exists, stretching from the bottom of the vagina to
the vestibule, and containing a thick plexus of veins; it is composed of longitudinal,
but more especially of transverse, long fibre-cells, with wavy ends. The structure
of the clitoris, glans clitoridis, bulbus vestibuli, &c, is analogous to that of the
corpora cavernosa in the male.
"In the spleen of the human body, Kolliker has never been able to discover smooth
muscular fibre, either in its covering, or in the larger fibrous bands; but in the
microscopical fibrous bands he has found elements which he thinks are of a muscular
nature. He also states, that in birds, reptiles, and fishes he has found some muscu-
lar fibre in the fibrous bands of the spleen. The existence of smooth muscular
fibre in the blood-vessels and lymphatics is indubitable; Kolliker recommends the
middle-sized arteries and veins for examination. In the aorta and trunks of the
pulmonary arteries, the middle coat is composed alternately of muscular and elastic
membrane, with fibro-cellular tissue. These muscles consist of fibre-cells, contain-
ing nuclei. The larger veins of the human body present, externally to their lining, a
single or double layer of elastic fibre, a simple coat of transverse muscular fibre-cells,
mixed with cellular tissue, to which succeeds externally a coat of longitudinal fibres.
In the middle-sized veins there is a middle coat of a pale reddish colour, composed
of alternate transverse and longitudinal fibres; the former are of fibro-cellular tissue
and contractile fibre-cells. Towards the periphery, the muscular structure decreases.
The veins of the uterus, which in the unimpregnated state present no peculiarities.
MUSCLE. 375
acquire a great development during pregnancy with regard to length and organization.
This does not so much proceed from the thickening of their walls, as from the
increasing size of the fibre-cells existing in the middle coat before pregnancy, and in
certain changes in the outer and inner coat caused by their acquiring a considerable
quantity of smooth muscular fibre. The very large veins which pierce the inner
muscular coat of the uterus at the point of attachment of the placenta, and which
communicate with its uterine portion, make an exception to this rule, as they have
only longitudinal muscular coats, which with the epithelium form the walls of the
vein.
"The following veins have no muscular structure:
1. " The veins of the uterine portion of the placenta.
2. "The veins of the cerebral substance, which are formed of epithelium and
cellular membrane.
3. " The sinuses of the dura mater.
4. "Breschet's veins of the bones.
5. "The venous cells of the corpora cavernosa in the male and female.
6. "Probably the venous cells ef the spleen. The muscular fibres of the
lymphatics are like those of the veins, they exist sparingly in the trunks, and in
greater number in the smaller branches."
MANIPULATION.
Muscular fibre is best studied by placing a small fragment of muscle
on a glass slide, moistening it with water, and tearing it with fine needles,
until the fibrillse are made apparent.
The sarcolemma or sheath of muscular fibre may be displayed on
rupturing the fibrillse by tension ; the sarcolemma will sometimes remain
unbroken after the fibrillse are ruptured, and may thus be examined. Another
method is to immerse the fibre in water before irritability be extinguished ;
the fibre imbibes the moisture, then contracts, and presses out the fluid
which raises the sheath into vesicles.
The study of the muscular fibre in the inferior animals is replete with
interest, the largest fibres being found in fishes and reptiles. In the lobster
and shrimp, the fibrillas are well seen, even after they have been boiled.
The muscular fibre of the pig is worthy of examination; it is so capable
of being resolved into oblong squares by sufficient magnifying power, that
it has been adopted as a test for object glasses of high power.
Mr. Quekett states that the nerves of muscular fibre are best studied in
the thin layer of muscle, which forms part of the abdominal wall of the frog.
Some of the capillary vessels maybe also here seen: these vessels, how-
ever, are best observed after they have been filled with fine injection when
their relation to the primary fasciculi can be made apparent.
Muscular fibre, whether injected or not, is best preserved in fluid, in flat
or thin glass cells, so it may be examined with high powers.]
376
THE SOLIDS.
ART. XIX; — NERVES.
The nervous system has been divided into two orders or lesser
systems; the cerebro-spinal, which includes the brain and spinal cord,
together with the nerves which proceed therefrom, and the sympa-
thetic systems. The former, which admits of still further leading
divisions, presides over animal life, its nerves administering to sensa-
tion, and being distributed to the principal organs of locomotion, the
muscles, as well as to those of the senses; the latter is connected
with the functions of organic life, and supplies principally the viscera
and glands with nerves.
Corresponding with the presumed functional differences of the two
systems, there are also certain structural differences, the nature of
which will shortly be described.
STRUCTURE OF NERVES.
Cerebro-spinae System. — The nervous matter constituting the
cerebro-spinal system consists of two very distinct substances, a gray,
cineritious, cellular, or secreting structure, and a white, conducting,
or tubular structure.
Secreting or Cellular Structure. — The very numerous situations
in which the gray matter of the brain and spinal cord is encountered
need not here be described at any length: it will be sufficient to
observe, that in the cerebrum it occupies principally an external sit-
uation, a layer of it of about the one-eighth of an inch in thickness,
extending over the entire surface of its convolutions; but that it is
also found in lesser quantities in several localities in the interior of
the cerebrum, as in the optic thalami, corpora striata, tuber cinereum,
crura cerebri, &c; that, on the other hand, in the cerebellum, pons
Varollii, medulla oblongata, and spinal cord, it is deep seated, forming
the central portion of these organs.
The secreting substance, or gray matter of the brain, is made up
of a granular base, in which are contained numerous nucleated cells
of different sizes and forms. In the gray matter of the convolutions of
the brain the granular base is very abundant, the cells small and round,
and in less proportion than the base itself: in the tuber cinereum, in
the cerebellum, and in the gray matter of the cord, the small granular
cells are extremely abundant, and the granular base is diminished in
quantity. (See Plate XLV. figs. 2, 3.) ■
NERVES. 377
Now, the granular base and the small granular cells constitute the
principal portion of the substance of the gray matter, wherever-
encountered: in certain localities, however, cells of different forms
and of considerable magnitude are met with: these cells have been
termed ganglion cells.
Ganglion Cells. — Ganglion cells are encountered in different por-
tions of the cerebro-spinal system, as in the locus niger of the crura
cerebri, in the gray matter of the arbor vitas, and corpus dentatum of
the cerebellum; in the medulla oblongata; in the spinal cord for its
entire length, and according to Valentin and Purkinje, in all the extent
of the cerebral hemispheres, especially in the posterior lobes, and in
the gray lamina of the spiral fold of the cornu Ammonis.
These cells vary greatly both in size and shape; many of them
attain a very considerable diameter, and they are, almost without
exception, all provided with caudate prolongations, which are fre-
quently branched. (See Plate XLIV. fig. 4.)
The ganglioniform cells of the locus niger are for the most part
small, and irregularly stelliform in shape: those of the gray matter
of the cerebellum are pyriform, the spinous and often-branched
processes, usually two or three in number, proceeding from their
narrow extremities: many of the cells of the medulla oblongata are
triangular, the spines arising from the angles, and being much pro-
duced, those of the spinal cord are usually very large, irregular in
form, and are furnished with numerous prolongations.
These cells are highly and uniformly granular: they frequently
contain pigmentary matter, and enclose a nucleus, which again is
provided with its nucleolus, and both of which are remarkable for
their exceeding brilliancy.
Ganglion cells are, doubtless, connected with the secretion of the
nervous element or fluid : the use of the prolongations with which
they are furnished, and the precise relation of these with the adjacent
structures, the smaller secreting cells and the nerve tubules, is not yet
well ascertained: it has been conjectured, however, that the caudiform
processes are directly continuous with the tubules ; a view which is
certainly incorrect.
Mixed up with the ganglion cells wherever met with, but especially'
with those occurring in the gray matter of the cerebellum and spinal
cord, a considerable number of branched and nucleated fibres may be
seen, similar in appearance and structure to those of unstriped muscle,
and more particularly resembling the gelatinous filaments of the sym-
pathetic system, from which they in all probability really proceed.
378 THE SOLIDS.
There is a second description of ganglion cell, not contained in
either the brain or spinal cord, but found in the various ganglia, as
the Casserian, Optic, Ophthalmic, Spinal, &c, formed in connexion
with the nerves of the cerebro-spinal and sympathetic systems, and
which may be here described.
These cells resemble the ganglion corpuscles already noticed in
their general structure, but differ from them in form, being more or
less round in shape, and destitute of the branched processes belonging
to the latter. (See Plate XLV. fig. 4.)
The mode of multiplication of ganglion cells is not well understood :
it is possible that the numerous granules contained in each are the
germs of the future cells Adhering to the surface of many of the
larger ganglion cells of the second form, a number of nucleated par-
ticles or lesser cells may frequently be observed, forming a kind of
capsule around them, which, however, is entirely external to the
proper membrane of the cells. (See Plate XLV. fig. 4.)
Tubular Structure. — The white fibrous substance of the brain,
spinal cord, the nerves of motion and of special sensation, is composed
of unbranched tubules, the diameter of which is subject to considerable
variation. The tubules of the cerebrum are exceedingly slender, as
are also those of the nerves of special sense : those of the cerebellum,
spinal cord, posterior root of spinal nerves, and of the sympathetic
system, are of somewhat larger calibre, while those of the motor
nerves are of still larger size, and of firmer texture. See the figures.
The tubules of the white substance of the cerebrum are especially
prone to become dilated at intervals, or varicose. (See Plate XLIV.
fig. 7.) This condition was formerly supposed to be natural, and it
was presumed that by this character the nerves of special sense
could be discriminated from those of motion: there is little doubt,
however, but that this varicose condition of the fibres is abnormal,
and that it is produced by the pressure and disturbance to which
they are subject during examination. The tubules of the cerebellum
are subject to a like change, although in a less degree; those of the
nerves of motion are but little prone to the alteration, these becoming,
when much disturbed, broken into fragments, many of which assume
a globular form, and all of which are greatly corrugated. (See Plate
XUY. fig. 1.)
The nerve tubules contain a fluid matter, and it is the collection
of this fluid in certain parts of each tubule, the result of pressure,
which occasions the distension of the membranous wall of the tubes.
NERVES. 3T9
and which gives rise to the varicose condition described. Such is,
at least, the most probable explanation of the exact nature of this
condition.
The tubules of the cerebrum, cerebellum, spinal cord, and motor
nerves, &c, present an average diameter: nevertheless, much differ-
ence may be detected in the size of the tubules taken from the same
portion of the nervous system : those of the spinal cord agree in their
average size with those of the cerebellum.
The tubes of the cerebrum, of the nerves of special sense, and of
the cerebellum, are so small, that it is impossible to ascertain with
certainty the amount of organization which really belongs to them :
this, however, is not the case with those of the motor nerves, which
are so much larger. (See Plate XLIV. jig. 1.)
Each tube of a motor nerve consists of an investing sheath or
neurilemma, an inner elastic and but little consistent matter, the
"white substance of Schwann," which forms a pseudo membrane,
and which includes the third constituent of the nerve tube, a soft and
semi-fluid matter, which, however, would appear in some cases to
become solid, and to exhibit a fibrous fracture: this matter has been
termed the "axis cylinder."
It is a matter of some difficulty to display the investing sheath, or
neurilemma, around the fibres in their fresh and unaltered state: it
may, however, be easily detected, and its structure 'recognised in a
portion of motor nerve which has been immersed for some hours in
spirit : it will then be seen that it is made up of nucleated fibres, the
nuclei in the sheath of fcetal nerve tubes being of considerable size,
and presenting a smooth aspect. (See Plate XLIV. jig. 2.)
Todd and Bowman describe the outer membrane of the nerve
tube, and to which alone the word neurilemma should be applied,
"as an homogenous and probably elastic tissue of extreme delicacy,
analogous to the sarcolemma of striped muscle, and, according to our
observation, not presenting any such distinct longitudinal or oblique
fibres in its composition as have been described by some writers."
It will be observed that this description does not accord with that
given by the author.
The white substance of Schwann, on the contrary, is best seen in
the motor nerve tubes, which are perfectly recent, and which have
been but little disturbed : its thickness is indicated by a double line
which runs along each side of the tube : it does not present any trace
of organization : it is very elastic, and its contraction gives rise to the
380 THE SOLIDS.
corrugated appearance presented by the tubes of motor nerves which
have been disturbed and broken. (Plate XLIV. fig. 1.)
The existence of -the third constituent of the nerve tube, the "axis
cylinder" of Rosenthal and Purkinje, is best determined by the immer-
sion of the fibres in either ether or acetic acid, which breaks it up into
granules and vesicles. (Plate HJAV.fig. 3.)
In albumen the nerve tubes and nervous tissue in general undergo
but little alteration, and it is therefore in this fluid that its examination
is best conducted.
But the tubes of the white fibrous material of the cerebrum,
cerebellum, and spinal marrow, just described, form one element only
of its structure; another is invariably present, forming indeed the
greater portion of its substance; and it is somewhat strange that it
should have been overlooked by observers: this element consists of
globules of every possible size, which, when free from pressure and
undisturbed, are perfectly spherical, but which are put out of shape
by the slightest compression or disturbance. It is not easy to deter-
mine whether these globules are true cells or not: they present the
greatest possible variety of size : they have the colour and consistence
of oil; but nevertheless appear to be hollow, and frequently present a
spot which bears much resemblance to a nucleus. (See Plate XLIV.
fig. 6.)
It now only remains to be observed, that the nerves of special
sense, as the optic, olfactory, and auditory, present a structure pre-
cisely analogous to that of the white substance of the cerebrum.
Sympathetic System. — The nerves entering into the formation
of the sympathetic or organic system, differ both in appearance and
structure from those derived from the cerebro- spinal system: thus,
the great sympathetic cord itself, as well as the organic nerves con-
nected with it, present a reddish gray colour, are soft and gelatinous,
and do not readily admit of division in the longitudinal direction,
although they are easily torn across by any extending force : these
differences of colour and of consistence are dependent upon a differ-
ence of structure. The great sympathetic cord itself, and the organic
nerves connected with it, are composed of two distinct descriptions
of fibre; first, of the ordinary tubular fibre, which, however, is of
small diameter, and therefore readily becomes varicose, and second,
of nucleated filaments, in every appreciable respect resembling those
of unstriped muscular fibre. Henle has called these fibres "gelatinous
nerve fibres."
NERVES. 381
The relative proportions existing between these two kinds of fibre
differ in different nerves : thus, in some cases, the gelatinous fibres
are by far the most numerous ; in others, the tubular fibres prepon-
derate. The gelatinous or gray filaments are best seen in what are
called the roots of the sympathetic ; that is to say, in the branches
which, accompanying the carotid artery, proceed from the superior
cervical ganglion to the fifth and sixth pair of cerebral nerves, and in
those which descend from the same ganglion and follow the course
of the carotid. In these the proportion of tubular fibres' is but small,
as one to six; and they are also isolated from each other, each being
surrounded with a number of gelatinous fibres. This disposition of
the nucleated fibres has led Valentin to consider that they form a
sheath around the tubular fibres, each gray nerve, according to that
observer, being composed of a number of fascicles or bundles. Henle,
however, objects to this view, considering that the fibres are too large
for a sheath, and remarking that the gray nerves do not separate into
such bundles, but divide much more readily in such a way as that the
tubular fibre, is found at the border of the bundle. Henle, therefore,
considers it to be more natural to regard the gray nerves as forming
solid threads, composed of nucleated filaments, between which the
tubular fibres run.
The tubular fibres are more numerous than in the roots of the
great sympathetic, in the majority of the visceral nerves, in the
branches which proceed from the cardiac and hypo-gastric plexuses,
&c; in these the tubular fibres may be seen enclosed within the gray
filaments, forming many bundles. Their number becomes still more
considerable in the great sympathetic cord itself and the splanchnic
nerves; the cardiac nerves are almost entirely formed of tubular
fibres. In all these nerves the tubular fibres are observed to be of
smaller diameter than they are in those which are distributed to the
voluntary muscles.
In consequence of the great difference which exists between the
structure of the tubular nerve fibre and that of the gelatinous nerve
fibre, it has been a matter of doubt with some observers whether the
latter should be regarded as a true nerve fibre or not.
The following is a brief enumeration of the various anatomical
and microscopical facts hitherto recorded, both in favour of and
opposed to the opinion of the nervous character of the gelatinous
filaments just described.
The chief structural considerations which may be urged in favour
382 THE SOLIDS.
of the opinion that the nucleated filaments associated with the various
nerves of the sympathetic system are true nerve filaments are —
1st. The origin of the gelatinous filaments from the ganglia of the
sympathetic, as first distinctly affirmed in the researches of Volkmann
and Bidder.*
2d. The tubular character of these filaments, as shown by T.
Wharton Jones. f
3d. The peripheral distribution of the gelatinous filaments, as
asserted by many observers, but particularly by Bidder, who even
states that he succeeded in counting their number in the transparent
septum of the auricles of the frog's heart.
4th. The peculiar structure of the ganglion caecum, discovered by
Mr. T. Wharton Jones, in connexion with one of the ciliary nerves
of the dog. J
5th. The variable, yet fixed proportions of gelatinous and tubular
fibres occurring in different nerves, as described especially by Henle.
6th. The occurrence, as stated by Todd and Bowman, of nucleated
filaments very similar to the gelatinous fibres of the sympathetic, "in
parts where their nervous character is indubitable, as in the olfactory
filaments, and the nerve in the axis of the Pacinian corpuscle, exhibits
very much the same appearance, save that it is devoid of nuclei. "§
7th. The resemblance borne, according to the observations of
Schwann, || between the tubular nerve fibre in the early stages of its
development, in which it is described as being nucleated, and the
adult gelatinous fibre.
8th. The origin of the gelatinous filaments from the cells themselves
composing the ganglia of the sympathetic, as the observations of
several observers tend to prove.
These various facts thus briefly referred to, could they all be fully
depended upon, would, doubtless, make out not merely a strong, but
even a convincing and unanswerable case in favour of the nervous
character of the gelatinous filaments: unfortunately, however, those
facts which, if they could be relied upon, would be the most conclu-
sive, are open to question: such, for instance, as the peripheral
distribution of the gelatinous filaments, their presumed origin from
* Die Selbstandigkeit des Sympathislten Nervensyslems durch Analomische Unter-
suchungen nachgewiesen Von J. H. Bidder und A. W. W. Volkmann. Leipsig, 1842.
f Lancet, April 24th, 1847. \ Lancet, November 14th, 1846.
§ Physiological Anatomy, part hi. p. 142.
11 See Wagner's Physiology, translation by Willis.
NERVES. 383
the ganglionic corpuscles, and the asserted resemblance between the
tubular nerve fibre in an early stage of its development and the fully-
grown gelatinous filament: it will presently be shown, indeed, in the
observations on the growth of the primitive nerve tubule, that no
such resemblance exists.
Subtracting, then, the points referred to in the 3d, 7th. and 8th
headings, no one conclusive fact remains of the position that the
gelatinous fibres are really nervous.
Against the opinion that the gelatinous filaments are nervous, may
be urged :
1st. The positive structural identity between the gelatinous nerve
filament and the fibrilla of unstriped muscle, and the great improba-
bility, as a consequence, that one and the same structure should have
to perform two such distinct functions as must necessarily belong to
a muscular fibre and a nerve tube.
2d. The apparent structural unfitness of nucleated filaments to
serve as a conducting medium of the nervous force.
3d. The evidently tubular character of the nerve filaments in parts
which, from their nature, we should expect would be preeminently
supplied by the gelatinous filaments.
4th. The fact of the non-occurrence of gelatinous fibres, separate
from the tubular, is strongly opposed to the idea of the independence
of the former.
The above short summary will serve to give some idea of the state
of the much-canvassed question of the nervous or non-nervous char-
acter of the gray or gelatinous filaments of the sympathetic.
STRUCTURE OF GANGLIA.
The ganglia consist of the peculiar globules already described, of
nerve tubules, and of gelatinous filaments.
Each ganglion is enclosed in an investing tunic of fibrous tissue?
a continuation of the common envelope of the nerves which enter and
depart from it, and which sends down dissepiments which divide the
contained globules into parcels, and thereby give the ganglion the gen-
eral arrangement and character of a gland.
The gelatinous nerve filaments in the ganglion form a kind of inner
capsule, and their arrangement is thus described by Henle: "Besides
the nervous fibres properly so called of the soft nerves, one meets
with also, in the ganglions of the great sympathetic, gelatinous fibres
which have special relations with the ganglionic globules. The fibres
384 THE SOLIDS.
of a bundle expand in the form of a funnel, in order to embrace a
globule or a series of globules, and unite together afterwards afresh,
to separate again a second time. In this way we often come to draw
out of a ganglion entire threads of gelatinous fibres, which are dilated,
in the manner of a chain of pearls, and enclosing the globules in their
dilatations."
The proper tubular fibres enter the divisions of the ganglion in
bundles, subsequently separate from each other, and ramify among the
ganglion globules in a waved and serpentine manner.
The arrangement of the ganglion globules and nerve tubules just
indicated, tends to show that these are really the only essential
elements of a ganglion.
The ganglia are supplied with blood-vessels.
It will be apparent from the above description that the ganglia have
all the structural characteristics of glands, and therefore there can
be little question but that they are really glandular organs, and that
the tubular fibres which pass through them carry away the fluid,
which is destined to exercise its influence on the parts and organs to
which the nerves are themselves distributed.
The question as to the origin of either the. tubular fibre or the gela-
tinous filament from the ganglionary corpuscles, is still an undecided
one, the weight of evidence being opposed to the idea that either order
of fibres has any origin from these corpuscles.
ORIGIN AND TERMINATION OF NERVES.
Origin. — But little that is certain is known respecting the exact
mode of origin of the numerous tubules composing the nerves, and of
the precise relation of these with the cellular or secreting element of
the ganglionic centres. The observations of Dr. Lonsdale,* however,
render it highly probable that the greater portion at least of the nerve
tubes have a looped origin in the brain and spinal cord : that gentle-
man having made out the interesting fact, that in two fetuses, in the
one of which both the brain and spinal cord were deficient, and in the
other the brain only, the extremities of the nerves, which extended
into the cavities of the spinal column and cranium, were made up of
looped nerve tubes imbedded in an imperfectly developed granular and
cellular matter, apparently of a ganglionic character. Now, from
what is known respecting the laws of development, it would appear to
* Edinburgh Medical and Surgical Journal, No. cxvii.
NERVES. 3S">
be a perfectly justifiable and natural inference, that the nerve tubes,
when fully developed, have a similar mode of origin.
According to some observers, certain nerve tubes are connected
with and take their origin from the prolongations with which the cau-
date variety of ganglionary cells are provided ; this view, however, is
confidently denied by many other investigators, and the point is one
which is still involved in considerable uncertainty : for myself, I would
observe, that I have never succeeded in making a single observation
favourable to such a conclusion. Notwithstanding, however, the
doubts which are now entertained respecting the modes of origin of
nerve tubes, the question is assuredly one which, at some future day,
will be satisfactorily determined by direct observation.
It is also still uncertain whether nerve tubules originate in the
ganglia not included in the brain, as in those connected with the
encephalic nerves, and those of the sympathetic system.
When speaking in the preceding remarks of the origin of nerves,
that extremity of them is implied which is in connexion with the brain
and spinal cord: it is questionable, however, in the case of the nerves
of special sense, whether it would not be more proper to consider
their peripheral rather than their central extremities as their true
origins; a view supported by the consideration that the .sensations
arise in, and proceed from, the organs of the senses inwards towards
the brain, the great centre of nervous structure and force, as well as
by the fact, that the peripheral extremities of these nerves are gener-
ally, if not invariably, connected with ganglionic cells; such an
association of the two elements is known to exist in the eye, in the
ear, in the nose, and probably exists also in the papillae of the tongue
and skin.
Termination. — It was not known until within the last four or five
years that nerves had any real termination: it was up to that time
generally considered that the nerve tubes invariably ended in the
same manner as it is now supposed that they originate, viz : in loops ;
and there can be little question but that such a mode of termination,
though not universal, is at least very frequent: thus, the arrangement
of the primitive nerve fibres in loops has been described by Valentin,
in the pulps of the teeth; by Muller, in the membrana nictitans, and
in the mucous membrane of the throat of the frog; in the papillae of
the skin and tongue, by Todd and Bowman. The loops are formed
by one or more of the nerve tubes, separating themselves from the
bundle of tubes composing every nerve of any magnitude, and after-
•25
386 THE SOLIDS.
wards either passing into and mingling with those of a neighbouring
nerve, or else returning back to that from which originally it started.
It is now, however, very certain that some at least of the nerve
tubes have a real termination : this is indisputably the case with the
single filaments which enter the Pacinian bodies; it has also been shown
to occur with many of the primitive tubes distributed to muscles.
PACINIAN BODIES.*
The Pacinian bodies are found in considerable numbers attached
to the cutaneous nerves of the hands and feet, especially to those of
the extremities of the fingers and toes ; they are also met with, though
more sparingly, on other spinal nerves, on the plexuses of the sympa-
thetic, but never on the nerves of motion, and in the mesentery ; in
that of the human subject, however, they are only with great difficulty
to be discovered, owing to its thickness, and the quantity of fat usually
contained in it : in the mesentery of the smaller mammalia, as the cat,
rabbit, &c, and more particularly when these are in a lean state, they
may be readily discerned with the naked eye, and the entire of their
structure followed out without even the employment of a reagent: it
is, therefore, in these animals that they are studied to most advantage.
The Pacinian bodies vary greatly in size, but are usually as large
as the head of a pin of ordinary magnitude; they are of an oval or
pyriform shape, are perfectly translucent, attached to the nerve
filaments by short pedicles, and occur either singly or sometimes in
pairs. (See Plate XL VI. fig. 1.)
So large are these peculiar bodies, that the whole of their structure
may be followed out with object glasses of an inch and half-inch foci;
when examined with these magnifying powers, each Pacinian body is
observed to consist of numerous concentric lamellae or capsules
disposed with much regularity; these lamellae are formed of white
fibrous tissue, contain numerous nuclei in their substance, and are-
separated from each other by distinct intervals which contain fluid ;
the spaces intervening between the plates do not communicate and
diminish gradually, but regularly from without inwards, so that the
* The discovery of these remarkable bodies constitutes one of the happiest and
most beautiful results of the application of the microscope to minute anatomy.
Pacini first noticed them in 1830, subsequently in 1835; but it was not until 1840
that he gave an account of them. — (Nuoci organi scoperli nel Corpo umano dal Dolt
Filippo Pacini, Pislqja.) A. G. Andral, Camus, and Lacroix, announced their exists
ence at a Concours at Paris, in 1833, but do not appear to have recognised their real
character.
NERVES. 387
central lamellae are almost in contact with each other, from which
cause they present a darker aspect than do those having appreciable
spaces dividing them the one from the other: these capsules have
been distinguished from the rest by the term the "inner system of
capsules." It is this regular disposition of the lamella?, together with
their gradual approximation, which imparts so beautiful an appearance
to these strangely constituted organs. The capsules, however, are
not continued to the very centre of the Pacinian body; but in that
situation a cavity, having a somewhat elliptical form, and filled with
fluid, exists. This cavity opens externally by means of a canal which
pierces the whole of the lamellae, and the sides of which canal are
formed by the union of those lamellae ; into this canal a single nerve
tube passes, enters the central cavity just described, which it trav-
erses from end to end in a straight line, terminating in a slightly
enlarged extremity, which is described as being attached to the inner
wall of the distal end of the central chamber; the nerve tube, imme-
diately on its entrance into this chamber, loses its double and defined
border, in consequence, it is presumed, of the absence of the white
substance of Schwann. (Plate XLVI. figs. 2, 3.)
Such is a brief and general description of the Pacinian body ; one
or two other points of a less evident character still remain to be
noticed. It has been stated that the capsules contain elongated
nuclei in their parietes, that they are formed of fibrous tissue, and
that the spaces between them have no communication with each
other: if the outer and larger capsules be carefully examined, it will
frequently be observed that they present a double edge, separated by
a faint interval, and conveying the impression that each capsule is
made up of two distinct membranes ; it is in this interval that the
nuclei are lodged: that the inter-capsular spaces do not communicate
with each other, is proved by the fact, that when the outer capsules
are pierced through, the fluid escapes only from the spaces which
have been opened into; if the whole of the capsules have been
divided, the entire corpuscle immediately collapses. (It is a curious
fact that a Pacinian body, allowed to dry up, does not again absorb
fluid, and expand to its natural size.) It has also been observed that
the capsules are united to each other at the proximate extremity of
the Pacinian body along the sides of the canal already described:
according to Pacini, they are also bound together at the distal end by
a band of fibrous tissue, which he calls the "inter-capsular liga-
ment :" the existence of this ligament has been denied by Henle and
88S
THE SOLIDS.
Kolliker.* Todd and Bowman do not deny its existence, but state
that they have seldom seen it reach the surface of the corpuscle.")"
Pacinian bodies not unfrequently present varieties of form and
structure: it is possible that many of these admit of explanation on
the supposition that in some instances they are multiplied by self-
division: thus, sometimes the distal end of the central chamber is
bifid, the nerve tube being also divided; in others, a single corpuscle
will be found to contain two distinct chambers and nerve tubes, each
being surrounded by a certain number of capsules, but which again
are themselves included in a number of other capsules which embrace
both the sets of inner membranes: again, in other instances, two
Pacinian corpuscles, entirely formed, but yet not altogether separated
from each other, being connected by a few of the capsules, will be
situated upon a single primitive nerve tube: a fourth peculiarity,
which may be noticed more frequently than any of the others, is the
curling back of the extremity of the central chamber, the innermost
capsules describing the same curvature. (See Plate HhYI.figs. 4, 5.)
•DEVELOPMENT AND REGENERATION OF NERVOUS TISSUE.
Development of nerve fibres. — The following is the account given
by Schwann of the development of the nervous cords as rendered by
Willis in his translation of Wagner's "Physiology," the references to
the figures only being omitted. "The nerves appear to be formed
after the same manner as the muscles, viz : by the fusion of a number
of primary cells, arranged in rows into a secondary cell. The primary
nervous cell, however, has not yet been seen with perfect precision,
by reason of the difficulty of distinguishing nervous cells while yet
in their primary state from the indifferent cells out of which entire
organs are evolved. When first a nerve can be distinguished as such,
it presents itself as a pale cord with a longitudinal fibrillation, and in
this cord a multitude of nuclei are apparent. It is easy to detach
individual filaments from a cord of this kind, in the interior
of which many nuclei are included, similar to those of the primitive
muscular fasiculus, but at a greater distance from one another. The
filaments are pale, granulated, and (as appears by their farther devel-
opment) hollow. At this period, as in muscle, a secondary deposit
takes place upon the inner aspect of the cell membrane of the
* Ueber die Pacinisclien Kbrperchen an den Nerven des Menschen und der Sauge-
ihiere. Zurich, 1844.
f Physiological Anatomy, vol. i. p. 397.
NERVES. 389
secondary nervous cell. This secondary deposit is a fatty white-
coloured substance, and it is through this that the nerve acquires its
opacity. With the advance of the secondary deposit, the fibrils
become so thick, that the double outline of their parietes comes into
view, and they acquire a tubular appearance. On the occurrence of
this secondary deposit, the nuclei of the cells are generally absorbed ;
yet a few may still be found to remain for some time longer, when
they are observed lying outwardly between the deposited substance
and the cell membrane, as in the muscles. The remaining cavity
appears to be filled by a pretty consistent substance, the band of
Remak, and discovered by him. In the adult, a nerve, consequently,
consists, 1st, of an outer pale thin cell membrane — the membrane of
the original constituent cells, which becomes visible when the white
substance is destroyed by degrees; 2d, of a white fatty substance,
deposited on the inner aspect of the cell membrane, and of greater or
less thickness; 3d, of a substance, which is frequently firm or consist-
ent, included within the cells, the band of Remak."
The author's observations lead him to entertain views of the devel-
opment of the primitive nerve tube essentially distinct from those
expressed by Schwann in the account quoted above : according to
these observations, the outer covering of the nerve tube does not
consist of a structureless membrane, as is supposed by Schwann, as
well as most other observers, but is constituted of a nucleated form
of fibrous tissue. (See Plate XLIV. jig. 2.) Now, the nuclei
observed by Schwann the author believes to be concerned in the
development of the fibres, of which the proper membrane of each
primitive nerve tube is wholly constituted, and that they do not by
their growth give origin to a transparent tubular membrane.
In the nerve tubes of both young and adult animals, smooth bodies
of an oval form and large size, their diameter exceeding that of the
tube itself, may always be observed ; the nature of these, and the
part taken by them in the structure and development of the nerve
tube, I have not been able to determine.
Development of Glandular Nerve or Ganglionary Cells. — The
nervous matter composing the two or three systems into which, in
the present day, it is divided, presents all the essential and distinctive
characters of a true gland, so that its description would have been
more correctly given under the general heading of " Glands."
The nerve or ganglionary cells present essentially the same structure
as all other glandular cells, and are doubtless continually passing through
390 THE SOLIDS.
the same phases of development and destruction during the progress
of nutrition and secretion.
The secreting or glandular cells in the brain and spinal marrow are,
for the most part, aggregated into distinct masses, the term ganglia
being equally applicable to these masses as it is to those existing in
connexion with the nerves of the sympathetic system. Henle con-
siders that the principal development of new cells takes place on the
outer surface of the brain, which is the most vascular from its con-
tiguity to the pia mater, and that the more mature cells are gradually
conveyed inwards, coming thus into nearer connexion with the tubu-
lar or conducting fibres, the disintegration and removal of the older
cells determining the movement of the cells from without inwards.
This view, as applied to the gray matter of the convolutions of the
brain, is probably correct, and is to some extent confirmed by an
observation which I made several months since, viz : that the cortical
substance of the cerebellum consists of two distinct portions, separated
by a well-defined line, perceptible with a common magnifying-glass :
the outer portion is made up of a granular base, containing but few
fully-developed cells, while the inner portion consists almost entirely
of completely-formed cells. The distinct separation of the cortical
or secreting matter of the cerebellum into two portions is very remark-
able, and the purpose fulfilled by such an arrangement wholly obscure.
Regeneration of Nervous Matter. — The regeneration of the primi-
tive nerve tube admits of proof, both by experiment and direct observ-
ation. The experimental proof consists in the simple division of
nerves, and even in the removal of portions of them : the parts to
which the nerve is distributed, of course at first, lose their sensory
and motor endowments: these, however, after a variable time, are
more or less perfectly recovered, thus completing the experimental
proof. The direct proof is derived from the former : the recovery
of the power of a nerve after the excision of a portion of it, argues
strongly the fact of the regeneration of the nerve tubes; and this
result, by a careful microscopic examination, can be positively demon-
strated: the number of tubes in the renewed part of the nerve is
stated, however, to be less than in the original portions; and this in
part explains the reason of the restoration of the functions of a divided
nerve being usually but imperfect. Other proofs of the regeneration
of the nerve tubes may be gathered from the more or less complete
restoration of various sensitive and motor parts of the body, as well
as from the reunion of parts which have been entirely detached from
the body, as the nose, the top of the finger, &c.
NERVES. 391
With respect to the regeneration of the glandular element of the
nervous matter, but little definite or microscopic is known: from
analogy, however, it may be inferred, that like other cellular structures,
as the epidermis, epithelium, &c, it also is capable of a more or less
complete reproduction.
RESEARCHES OF M. ROBIN.
The following is a translation of an abstract made by the author
himself, M. C. Robin, of a paper communicated to the Royal Academy
of Sciences at the Seance of June 21st, 1847, entitled "Researches
on the Two Orders of Elementary Nerve Tubes, and the Two Orders
of Ganglionary Globules which correspond to them."
" The end of these researches is to show that the ganglions of the
spinal nerves and of the great sympathetic, do not give origin to
elementary nerve tubes, as many modern anatomists admit, as Han-
nover, Valentin, Remak, Bidder, and Volkmann, &c, &c. ; but that
all the nerve tubes arise exclusively from the spinal cord and the
encephalon; consequently that one can only regard these ganglions
as special little nervous centres, performing, with respect to certain
functions, the same office as does the cerebro-spinal centre for the
other functions. These reflections naturally occur to the mind when
one sees the cavity of the tubes or elementary nerve fibres given off
from the spinal cord, or from the encephalon, merge into the cavity
of the ganglionary globules at one of their poles, and reappear at the
opposite pole of the globule in the same manner that they entered.
"Setting out from a globule (cell), these nerve tubes proceed to lose
themselves in the organs. Thus, those peculiar cells, the agglomera-
tion of which constitutes the ganglions of nerves, are no other than
organs which are interposed between the origin of the nerve tube and
its termination at a determined point of its course, and, perhaps, there
is more than one upon each tube : they interrupt it in its course to
allow it once more to reappear; they change it, they modify its
structure at a point to immediately restore it.
" The authors who have hitherto written upon the subject have not
observed the entrance and exit of each elementary tube at the two
opposite poles of each globule, but only the one or the other. It is
this circumstance which has led them to consider each of these gang-
lionary globules as a little nervous centre of origin for each tube.
" There is yet another fact, still more important than the first, which
has not been pointed out by anatomists who have studied the structure
of nerves.
392 THE SOLIDS.
"They have all described but one order of globules: there are,
nevertheless, two which differ, the one from the other, in numerous
characters, deduced from the consideration of size, form, contents,
walls, &c. One of these orders of globules is always in connexion
with the elementary nerve tubes of animal life, or the large tubes, &c.
The other is associated especially with the elementary tubes of organic
or sympathetic life, or with the small tubes, &c. One never finds the
large tubes communicating with the second order of globules, and
reciprocally the small tubes are never in connexion with the poles of
the globules of the first order.
"It follows, from these facts, that one can no longer doubt the
existence of the two orders (altogether distinct) of elementary nerve
tubes named above, which, nevertheless, some authors have done
recently. (Kolliker.)
"The two orders of globules, and of the corresponding tubes, exist
in the posterior or sensitive roots of the nerves of the spinal cord, but
the globules do not exist in the anterior or motor roots.
"They exist also in the ganglions of the encephalic nerves and of
the great sympathetic; only in these last there is a much greater
number of globules and of slender tubes, than of globules and of large
tubes (thirty or fifty to one), more or less according to the ganglions.
In the spinal ganglions, on the contrary, there are about four or five
globules and large tubes to one of the other kind.
"These facts tend to confirm the observations of anatomists who
have pointed out the existence of the two orders of elementary tubes
in the nerves of animal life, and those of the great sympathetic, but
with predominance of the large tubes in the first, and of the slender
tubes in the second; notwithstanding which, no one of them has
pointed out the existence and the difference of the two orders of
ganglionary globules,
"The absence of ganglionary globules on the anterior or motor
roots of the spinal nerves anatomically distinguishes the elementary
tubes of motor nerves of animal life from those of the sensitive nerves.
But this decisive character can be remarked only in the short course
of the roots of the spinal nerves before their union and the mixture of
their tubes. If wishing to push still further the deductions to be drawn
from the preceding facts, we demand of ourselves what functions
should be attributed to the ganglionary globules, we should answer,
that they are the modifiers of the action which takes place in the
sensitive and in the organic nerves; but it is impossible to determine
the nature of this modification.
NERVES. 393
"Since the ganglia of the sympathetic and of the cereb#o-spinal
nerves enclose the same ganglionary globules, and the same element-
ary tubes, but only in different proportions, we see that we cannot,
with Reil, Bichat, &c, acknowledge two nervous systems independent
of each other. This opinion is founded on the communications of
the great sympathetic with the spinal nerves; on the fact of nerves
being furnished to the abdominal diaphragm of birds, exclusively by
the great sympathetic (Sappey) on the partial and successive substi-
tution of sympathetic nerves for spinal and encephalic in a great
many vertebrata."
The above highly interesting observations of M. Robin need con-
firmation, and it is to be hoped that microscopic anatomists will direct
their attention to the subject. In the many examinations which I
have made of ganglia, I have never recognised the presence of two
orders of ganglionary cells, nor have I ever perceived any attachment
between the tubes and cells. I would remark, however, that I have
made no examination of the ganglia and their constituent cells since
the publication of the researches of M. Robin. There is one defect
in the abstract of the author, of which we have given a somewhat
literal translation, viz : that the distinctive characters of the two
orders of ganglionary cells are not recited : it will be observed, also,
that no mention is made of their occurrence in either the brain or
spinal cord : from this I should judge that M. Robin was not acquainted
with the delicate cells described by me in Part X. of this work, as
existing in vast numbers in the white substance of the cerebrum, cere-
bellum, spinal cord, and nerves of special sense wherever this occurs.
394 THE SOLIDS.
NERVES.
[The examination of the nerves is best conducted by cutting thin slices
with a very sharp scalpel, or flat-bladed knife, in different directions, and
subjecting these to moderate pressure, having previously moistened them with
water or with serum. Other sections may be gently dissected with fine
needles, and the fibrillse separated. In all instances, the sooner the nerves
are examined after death, the more readily will their structure be determined.
Hints have already been given for viewing the neurilemma, the white
substance of Schwann, and the " axis cylinder " of Rosenthal and Purkinge,
and the localities pointed out in which the Pacinian bodies are found.
Dr. Stilling* gives the following instructions for examining the spinal
cord :
"I place a fresh spinal cord, and medulla oblongata, as they are taken from the
body, in weak spirit, and allow them to remain in it twenty-four hours; then I pour
off the spirit, and place fresh but stronger spirit on the parts, which, after two or
three days, is again poured off, and then the strongest rectified spirit is used; the
specimens being allowed to remain in it from four to eight days, acquire by degrees
such hardness as to allow of the finest sections being made. The sections being
provided (if from a recent cord), are then to be extended by means of a compres-
sorium. Low powers are best adapted for the examination; a lens of two-inch
focus being first used, and then others of higher power."
He directs the sections to be made with a sharp and broad razor, the sur-
face of which must be kept moistened with the spirits of wine.
Preparations of nerves can only be preserved in fluid ; for this purpose,
the naphtha-water, chromic acid, or Goadby's B-solution may be employed.]
* Lancet, Oct. 7th, 1843.
ORGANS OF RESPIRATION. 395
ART. XX. — ORGANS OP RESPIRATION.
The organs of respiration seem to stand alone in the animal
economy, and not to exhibit any strong structural relationship or
affinity with any other organ or organs comprised in that economy.
In their position and general form they bear some resemblance, in
the mammalia at least, to glands : this resemblance, however, is more
apparent than real, as becomes evident from the single consideration
that the lungs are essentially destitute of the innumerable granular
cells which constitute the chief bulk of true glands, and form their
distinctive and essential element. In a strictly natural arrangement,
the lungs would be more properly and correctly described in connexion
with the circulatory apparatus ; for essentially they are vascular organs,
their only indispensable constituent being blood-vessels, so situated,
indeed, as to admit of their being brought continually into contact
either with air, or with water impregnated with air.
The great object aimed at in the formation of the lungs of mam-
malia is the construction of organs which shall occupy but little
comparative space, and which shall yet present a greatly extended
surface, throughout which the blood and air may be brought into
close approximation. We shall now proceed to describe the manner
in which this purpose is accomplished.
The tissue of the lungs of man and other mammalia may be divided
into two systems of apparatus : the first comprises the circulatory or
vascular apparatus, consisting of arteries and veins, together with the
plexuses formed by the union of the capillaries proceeding from both
sets of vessels; the second comprises the respiratory or aeriferous
system, which includes the bronchial tubes, the air cells, and the
ciliated epithelium. The intimate structure of the lungs will be best
understood by an examination in the first place of the aeriferous
apparatus.
AERIFEROUS APPARATUS.
The aeriferous apparatus of the lungs consists of bronchial tubes
and air cells.
Bronchial Tubes. — The bronchial tubes are formed of cartilaginous
rings united by elastic tissue: the rings, however, are imperfect, and
are only present in the larger tubes, as those of the first, second, and
third or fourth diameters: in the smaller tubes they are absent, these
being composed entirely of a nucleated form of fibro-elastic tissue:
396
THE SOLIDS.
they divide repeatedly in a dichotomous manner : it is not easy, how-
ever, to determine the number of divisions which each bronchial tube
undergoes after its entrance into each lobule ; it would appear, how-
ever, that the intra-lobular ramifications are less numerous than the
inter-lobular branchings, the bulk of the lobule consisting chiefly of
air cells.
The bronchial tubes are lined throughout by mucous membrane,
which is invested by a stratum of cylinder ciliated epithelium. The
smaller bronchial tubes are eminently elastic and contractile, by
virtue principally of the elastic tissue of which they are chiefly
formed. This elasticity is still further increased in the case of the
larger tubes by the presence of muscular fibrillee of the unstriped kind.
Air Cells. — The air cells are minute cavities of variable size, of an
angular form, not dilated, which communicate freely with each other,
and the parietes of which are formed of a diaphanous, tough, highly
elastic and delicately fibrous membrane, which contains and supports
the capillary blood-vessels, and the interior of which is lined by a modi-
fied mucous membrane also invested with a layer of ciliated epithelium.
From this description, it becomes evident that the air cells contain
the same structural elements as the smaller bronchial tubes themselves,
and that they therefore differ from these solely in form and arrange-
ment, possessing precisely the same general physical properties, being
in the same manner highly elastic, a property mainly dependent upon
the abundance of fibro-elastic tissue present in the lungs. (See
Plates XLVII. and XLVIII.)
That the air cells do really communicate freely with each other (a
fact which is now generally admitted, but which is yet denied by
Dr. T. Williams*) may be satisfactorily determined in many ways.
Thus, it is by no means difficult to see the circular and ever patent
openings of communication, both in injected and uninfected lungs ;
again, by injection with size, perfect casts of the cells may be
obtained : these casts, when a fragment of lung is torn up in water,
readily escape, by which means the variety presented by the cells in
form and magnitude may be accurately determined, as well as the
shape and number of the openings of communication. (See Plate
XLVIII. Jig. 2.) Not unfrequently these casts are more or less
coated with the epithelium lining the cells, as also represented in the
figure just referred to.
* "Essay on the Structure and Functions of the Lungs." College of Surgeons
London, 1842.
ORGANS OF RESPIRATION. 397
So perfect and consistent are the models of the air cells procured
in this way, that for some time I was led to entertain the idea that
each little mass of size was really enclosed in a delicate and structure-
less membrane, which I conceived to be the true air cell lining, and I
have scarcely yet been able to discard the notion altogether from my
mind. If the lung be injected with tallow, we do not procure casts
in the same number and perfection, because the tallow adheres closely
to the sides of the air cells. Sometimes I have seen casts even with-
out injection; but the occurrence of these is rare. It is, therefore, yet
possible that I have not been deceived, and that a structureless mem-
brane does really line the air cells, a modification of the mucous lining
of the tubes, the "basement membrane" of Bowman.
It would appear from an examination of these casts, that the num-
ber of openings of communication varies from one to five; usually,
however, but one, two, or three, are present.
When looking attentively at these casts, covered with epithelial
cells, and labouring under the impression that they were really distinct
structures, I have sometimes perceived cells of glandular epithelium,
one much larger than the rest, with a transparent border ; and this I
fancied was a fresh cell membrane in process of development.
The presence of epithelial scales in the air cells was first observed
by Mr. Addison;* but that gentleman was unable 10 determine
whether these were ciliated or not; subsequently Mr. Raineyf
advanced the statement that healthy air cells contain no epithelium.
In sections of recent lungs, it is a very easy matter not merely to
determine the existence of epithelium in the air cells, but also the
fact of its cylinder and ciliated form and character. Circular and
oval epithelial cells also occur; these are most probably ciliated cells
in a less advanced condition of development. (See Plate XLVIII.
fig. 3. and Plate XLIX. fig. 2.)
It has been stated that the air cells vary in size. This is the case
with even contiguous cells, as may be seen by a reference to the
figures : the air cells in the lungs of an adult are also much larger
than those of a child.
The fact of the epithelium extending from the bronchial tubes into
the air cells, would seem in itself to imply that the mucous membrane
*" Observations on the Anatomy of the Lungs," by Thomas Addison, M. D., 1841.
— Transactions, Medico- Chirurgic Society.
f "On the Minute Structure of the Lungs, and on the Formation of Pulmonary
Tubercle," by George Rainey. — Transactions, Medico- Chirurgic Society, 1845.
398 THE SOLIDS.
also lined them, at least in a modified condition, which is contrary to
the opinion expressed by Mr. Rainey.
VASCULAR APPARATUS.
The vascular apparatus of the lungs consists of arteries and veins:
these vessels, after numerous ramifications in the inter-lobular spaces,
unite together on the surface of the air cells, through the medium of
a beautiful and elaborate system of plexuses, each air cell being
furnished with its own separate plexus.
The manner in which the vessels, either arteries or veins, are dis-
tributed throughout each lobule is as follows: — first, large branches,
after having reached the lobule through the inter-lobular spaces,
extend over an area of several cells (see Plate XLVII. fig. 2) ; from
these, secondly, a number of smaller vessels proceed, which run in
the spaces between the cells, forming loops around them (see Plate
XLVII. fig. 3); third and last, from these inter-cellular vessels the
capillaries constituting the plexuses are given off. (See Plate XLIX.
fig. 3.) This distribution of the vessels is especially evident on the
pleural surface of the lung.
From the preceding description it does not appear that the capillarv
plexus belonging to each air cell is compounded of both venous and
arterial capillaries, but that in most cases it consists entirely of capil-
laries derived exclusively either from a vein or an artery.
It is thus evident that an air cell with its investing plexus of capil-
laries contains all the essential constituents of an entire lung, and
therefore that each air cell may be regarded as a lung in miniature.
It is well known that it is frequently a matter of great moment, in
a medico legal respect, to discriminate between a lung naturally
inflated and one artificially so: the test proposed, and ordinarilv
employed and relied upon, seems to me to be unworthy of full confi-
dence. I allude to the hydrostatic test: it is stated that, by firm
pressure, all the air contained in a portion of lung artificially inflated
may be expressed, so that it will sink in water; but that this cannot
be done in the case of a lung naturally inflated ; a portion of air will
always remain unexpressed sufficient to keep it afloat. I see no good
reason for this constant difference, since it is perfectly certain that a
lung may be most completely and entirely injected with air or fluid,
far more completely, I should be inclined to say, than occurs with air
naturally inspired, except perhaps during a forced inspiration. Not-
withstanding the uncertainty which seems to me to be attached to
ORGANS OF RESPIRATION. 399
this test, I yet consider that by a careful examination of the condition
of the blood vessels in the two lungs, the question may in most cases
be satisfactorily determined, whether has the lung been artificially or
naturally extended with air?
Previous to birth, it is known that the circulation of blood through
the lungs is of a very limited character, and that it is only after that
period, and during the first act or acts of respiration that the great
mass of vessels, principally capillaries, become carriers of blood.
The vessels, then, in the one case, viz: before respiration, will be
almost devoid of blood, and, in the other, after that act, replete with
that fluid.
Dependent upon this difference in the condition of the vessels, we
shall notice certain distinctive features, both general and micro-
scopical, in the case of the artificially and the naturally inflated lung.
The former, after inflation, will be observed to collapse to nearly its
previous size on the escape of the air : it will present a pale appear-
ance, especially evident if the lung be cut into, and when examined
with a lens, it will be seen that the inter-spaces between the lobules
and cells are pale, not being occupied with red vessels. Now, on the
other hand, the latter will be characterized by appearances the very
reverse: it, after inflation, will not collapse to nearly its previous size;
it will be somewhat red, and the intervals between the lobules and
cells will be seen to contain red vessels, in which, as well as in the
capillaries, the higher powers of the microscope will reveal the exist-
ence of red-blood discs.
PATHOLOGY.
Now that the normal anatomy of the lungs is well understood, the
several pathological conditions of those organs admit of a precise
and satisfactory explanation. The principal diseases of the lungs,
upon the exact nature and seat of which the microscope affords,
directly or indirectly, satisfactory information, are Emphysema,
Asthma, Pulmonary Apoplex)^, Pneumonia, and Tubercle.
Emphysema. — The essential pathological and microscopical char-
acters of Emphysema consist in an enlargement and rupture of a
greater or less number of air cells, whereby the cavities of several
distinct cells become thrown into one, with sometimes the escape of
air from the ruptured air cells into the inter-lobular cellular tissue.
When the air cells are simply dilated and ruptured, without any
escape of air from them, the Emphysema is lobular ; when, on the
400 THE SOLIDS.
;
contrary, the air passes from the cells into the cellular tissue, which
unites the lobules to each other, the Emphysema is termed inter-lobular.
It cannot be doubted but that this condition of the lungs interferes
very greatly with the efficiency of these organs ; the extent of surface
over which the air and blood are brought into contact being very
considerably diminished.
Asthma. — The microscope has revealed the fact that the smaller
bronchial tubes and air cells are principally constituted of a form of
elastic tissue, which, possessing marked physical properties, is yet, to
a certain extent, under the control of the nervous system. It is then
the irregular action and contraction of this tissue, determined partly
by physical causes and partly by irregular and unequal impressions
arising from internal causes conveyed to this tissue by the nerves,
which occasion and account for the distressing and peculiar symptoms
of Asthma.
Pulmonary Apoplexy. — Pulmonary apoplexy is simply a highly
congested condition of the vessels, which are principally capillary.
of the lungs. A congested vessel is of greater diameter than an
uncongested one, and, therefore, is capable of containing, and really
does contain, a far larger quantity of blood than the vessel in its
normal state. There are many stages or degrees of congestion and
of pulmonary apoplexy: the congestion may be slight, may engage
only one lung or a portion of one; the dilatation of the vessels may
be but trifling, and therefore the increased quantity of blood conveyed
by them will be but small; or, on the other hand, the congestion may
be very great, both lungs may be affected, and the dilatation of the
vessels may be considerable; the quantity of blood also contained in
such vessels will be very great. In cases of trivial or partial conges-
tion, a slight retardation in the progress of the blood only occurs ; in
the more severe and complete cases, the blood accumulates in the
vessels to such an extent as that the circulation is totally annihilated,
death being the necessary result of such a condition of things.
In what way may the occurrence of this congestion be explained,
and what is the cause of the cessation of the circulation? The cap-
illary vessels of the lungs are, of course, incapable of coveying beyond
a certain quantity of blood : any causes, therefore, and there are sev-
eral, which drive in upon the lungs a greater amount of the vital fluid
than its vessels are capable of circulating, would produce congestion:
the first effect of which is an accumulation of blood in the vessels;
the second, an enlargement of those vessels, the coats of which are
ORGANS OF RESPIRATION. 401
highly elastic, as a necessary consequence of the first; third, a total
cessation of the circulation, arising from the rapid aggregation of the
blood corpuscles in the vessels. The various degrees of congestion
may be followed out with the microscope in the most satisfactory
manner in the tongue of the frog, or in the web of the feet of that
creature. Some of the vessels will be but slightly dilated; other
capillaries, which in their normal state are capable of conveying only
a single row of corpuscles, will now be observed to contain two or
three rows; in others, again, the blood will have ceased to move
altogether.
These several changes in the condition of the blood and its vessels
during congestion, are all unaccompanied by structural alterations, by
which character congestion may be distinguished from inflammation.
Pneumonia. — The phenomena of congestion precede those of pneu-
monia, of which indeed it may be considered as the first stage; the
second stage of pneumonia, consists in the rupture of some of the
capillary vessels, and the escape of a portion of their contents (whence
proceeds the characteristic rust-coloured expectoration), as well as the
effusion without rupture of coagulable lymph through the walls of the
vessels, the consolidation of which in the air cells constitutes the con-
dition of the lung known by the name of hepatization : these results
are probably necessary consequences of the protracted congestion :
the third stage of pneumonia is attended by the formation and excre-
tion of granular cells in large quantities, imbedded in a fibrinous fluid :
the excreted matter may be either mucus, constituting the stage of
resolution, or it may be pus, when the pneumonia is said to terminate
in purulent infiltration: the difference between the two excretions is
one of degree rather than of kind. With respect to the nature and
origin of the granular corpuscles, some physiologists will have it that
they are the white corpuscles of the blood escaped from the vessels —
an opinion completely untenable: they doubtless have an origin
external to the blood vessels, and are to be regarded as of an epithelial
character, representing as a rule the peculiar epithelium of the surfaces
or parts from which they emanate.
Tubercle. — The earlier microscopic observers approached the
investigation of tubercle, especially of tubercle in the lungs, with the
expectation of finding in tubercular matter some peculiar element
or structure which should account for the fatality and apparent malig-
nity of that fearful affection, not knowing fully the true structure of
the organs of respiration, and therefore not perceiving clearly that this
26
402 THE SOLIDS.
fatality is occasioned rather by the peculiar structure of the lungs
themselves, than by any malignity in the character of the tuberculous
formation. Some of these observers have even fancied that they have
discovered in the matter of tubercle peculiar and characteristic cells :
it is now scarcely necessary to remark, that careful and extended
microscopic investigation does not warrant any such conclusion.
One of the most accurate views with which I am acquainted
respecting the nature of tubercle, is that put forth by Dr. Addison:*
"Tubercles of the lungs," he writes, "are composed of objects
originating from blood corpuscles, which have been arrested in their
circulation through the minute vessels of the structure of the air cells.
So long as this retardation is confined to the colourless corpuscles,
the morbid actions which ensue are strictly those of an abnormal
nutrition, and various forms of imperfect and degenerated epithelium
are the results ; but if it extend, so as to interfere with the free cir-
culation of the red corpuscles, we then have all the phenomena of
inflammation. No new elementary particles are formed to constitute
a tubercle, and although from the insidious nature of the primary
actions, from the delicacy of the structure, and the important charac-
ter of the function of the lungs, the treatment of tubercular diseases
must always be attended with more than common difficulties, still
there is every reason to believe that they are susceptible of prevention
and cure, especially if our efforts for the attainment of these ends be
enforced previous to the appearance of a cough, which is not a con-
comitant of the first stages of tubercular deposition in the lungs."
My own views of the nature of tubercle in the lungs differ in one
important respect from those of Dr. Addison ; that is, with reference
to the precise origin of the imperfect and degenerated epithelial cells.
Dr. Addison conceives that they are derived immediately from the
blood itself, while I consider that they proceed from the epithelium,
which has been described as lining the air cells themselves.
A tubercle, then, I would define as an accumulation of epithelial
scales, the imperfect and degenerate representatives of the true
epithelial cells of the organ or part in which the tubercle is itself
developed.
* "Experimental Researches." — Transactions of Provincial Medical and Surgical
Association, vol. xi. pp. 287, 288.
ORGANS OF RESPIRATION. 403
A tubercle of the lungs, at the earliest period of its formation, is
exceedingly small, occupying a single cell only ; when this cell becomes
filled with tubercular matter, a rupture of its membrane occurs, and
thus the extension of the tubercle takes place from cell to cell; this
extension at the same time being accompanied by a destruction and
displacement of numerous of the capillary plexuses.
After the above description, it need scarcely be observed that
tubercles of the lungs are not vascular.
404 THE SOLIDS.
LUNGS.
[The presence or absence of epithelium in the air-cells of the lungs is a
point of considerable importance, since Dr. Hassall defines tubercle to be an
accumulation of degenerate epithelial scales in the air-cells; a definition
that would possess little value if no epithelium was there present.
Since the paper by Mr. Rainey, in 1845, referred to in the text, in which
he contended that the air-cells were not furnished with epithelium, the same
gentleman has extended his inquiries to the lungs of inferior animals, and
he here finds in several instances demonstrative proof of the non-existence
of epithelium. His paper* thus refers to the opinion of those who still main-
tain "that the air-cells are lined with ciliated epithelium."
"The demonstration of this supposed fact has been attempted by filling the air-
passages with tallow or size, and then submitting the lung thus treated, and the casts
taken from the air-cells, to examination with the microscope. I may observe that
all the ramifications of the bronchial tubes have a very complete lining of ciliated
epithelium, which, by such a mode of preparation, might have been easily detached,
and broken up, and fragments of it forced into the air-cells; hence, such a mode of
procedure seems ill calculated to determine a point of so much delicacy. I am ready
to admit that corpuscles of various kinds may occasionally be found in the air-cells,
but these have not the most remote resemblance, either in their quantity or manner
of arrangement, to a lining of epithelium, especially of that kind which is called
ciliated epithelium. Mr. Addison was the first who described an epithelium, lining
the air-cells, w7hich he states to be in the form of round nucleated scales, with from
one to fifteen or more nuclei observable in a single scale." — (Philosophical Transac-
tions, 1842, Part ii. p. 162.)
" It is very evident from this description that Mr. Addison must have mistaken the
nuclei in the coat of the capillaries for an epithelium, an error which it is very easy
to commit, in examining the uninjected lungs, and which error can only be cor-
rected by comparing the lungs uninjected with those in which the capillaries have
been filled with injection. I have frequently seen the curve formed by a capillary
projecting beyond the free border of the pulmonary membrane, where it forms a
communication with an adjoining cell, presenting so much the appearance of a delicate
epithelium, that, had I not more than once seen a vessel in a similar situation in the
injected lung, I might have mistaken it for a portion of epithelium, lining an air-cell,
and considered that the air-cells have a lining, if not of ciliated, yet of pavement
epithelium, as some anatomists of the present day imagine."
Mr. Rainey describes the bronchial tubes of birds to be lined with ciliated
epithelium, as in mammals. The air-cells he found to be so infinitely small,
that it is impossible for them to be lined with epithelium, as he found upon
measurement that the epithelial scales from the bronchus of a pigeon were
_i_ of an inch in length, and -^^0 0I> an mcn *n breadth, while the air-
* Medico-Chir. Transactions, 1849.
ORGANS OF RESPIRATION. 405
cells, or air-spaces, on an average, measured only g^V o °f an mcn m
diameter, and some were even smaller.
He also observed that in the kangaroo many of the air-cells were so
minute, that a single cell of epithelium would have entirely filled them, and
that in the rat and mouse, in which the ciliated epithelium is of the same
size as in man, many of the air-cells were too small to receive an individual
particle.
Mr. Rainey considers that the essential and only true organs of respira-
tion, or rather of the aeration of the blood, are the pulmonary capillaries,
with the blood in them.
Quain and Sharpey* believe the air-cells to be lined with delicate, thin,
transparent mucous membrane, covered with a stratum of squamous epithe-
lium. This membrane, by a doubling inwards of itself, forms the intervening
septa.
MANIPULATION.
In addition to the methods already pointed out for the study of the air-
cells, the lung may be artificially inflated, and then allowed to dry. Thin
sections of the dried lung may then be made, and the size, shape, and num-
ber of air-cells readily examined. The capillaries can only be viewed by
injecting them ; this may be done by either the pulmonary artery or vein.
In the foetal subject, the lungs, with the rest of the organs, may be injected
from the umbilical vein.
Rossignol's experience in the injecting of the capillaries of the lungs is
worth here recording. He found that injections by the bronchial arteries
returned by both the pulmonary and bronchial veins, but not by the
pulmonary artery.
2dly. That the injections by the pulmonary arteries returned entirely by
the pulmonary veins, but not by the bronchial arteries; and 3dly, that by
injecting the pulmonary veins it was easy to fill all the other vessels ; viz :
the pulmonary artery and bronchial arteries and veins.
Portions of injected lung are best preserved in fluid. They should be
mounted in cells, just deep enough to allow the cover to be applied without
coming in contact with the object, as it is necessary sometimes to change
the focus of the object-glass so as to penetrate to the bottom of an air-cell ;
the fluid may be either spirit and water, naphtha, or Goadby's B-solution.
Some injected lungs show well when mounted in the dry way.
Plate LXXIII., fig. 2, shows capillaries and air-cells of the fcetal lung.
" " fig. 3, do. of an infant.
" " fig. 4, do. of an adult.
" " fig. 5, Bronchial laminae of an eel.]
* "Quain's Anatomy," by Sharpey and Quain, 5th edition, p. 1153.
406 THE SOLIDS.
ART. XXI; — GLANDS.
Much uncertainty has until recently prevailed as to what really
constitutes a gland : some have considered those only as true glands
which are furnished with distinct openings or excretory ducts; others
again have regarded those organs only as glands which give forth a
secretion: the former view of a gland would exclude the yascular
glands as well as some others, and the latter, although it would include
these, and, doubtless, also every other glandular structure, is not a
sufficiently obvious or structural character, the secreted product of
glands in many cases being furnished in small and scarcely apprecia-
ble quantities, and which again are immediately, on their formation,
absorbed, in some cases, into the circulation. Again, secretions are
supplied by parts and extended surfaces to which, although they are
essentially glandular, the term gland would scarcely be applicable ; of
this nature are the free surfaces of all membranes covered by epithe-
lium, as the mucous, serous, synovial, &c.
We have still then to inquire, first, what are the essential structural
elements of which all glandular organs or parts are constituted? and,
second, what is the exact definition to be given of a gland?
The researches of modern microscopists have indisputably proved
the fact, that the only essential elements of a secreting structure are
granular cells and a circulating fluid, the secreted product being
formed out of the latter by the vital endowments resident in the former.
According to this definition, the blood itself is to a considerable
extent glandular, inasmuch as it contains a vast number of granular
cells to which the elaboration of the fibrin is, in all probability, due.
Again, the free surfaces of all membranes are glandular; the epi-
thelium covering them constituting the one essential glandular element :
the varieties in the size and form of the cells representing this epithe-
lium have been already described in a former chapter of this work.
Following up this general definition of glandular structure, a gland
may be defined as a collection or aggregation of granular cells placed
in close approximation with a formative fluid, contained, ordinarily,
but not essentially, in the blood-vessels.
This definition of a gland embraces not merely those glands which
are provided with orifices or excretory ducts, but also those which
GLANDS. 407
have no such external or apparent channels of excretion, as the
vascular and other glands.
While it is certain that secretion takes place in the cavities of the
granular cells, as may be actually shown to occur in the hepatic,
renal and sebaceous cells, there is much reason to believe, from the
rapid and continual development and dissolution of successive genera-
tions of cells, as especially evident in the case of those of the
stomach and small intestines, that this secretion is liberated in many
instances only by the dissolution of cells themselves. From this view
of the relation existing between the secretion and the cells, it
would appear that the secretive process is accompanied by an
endosmotic action.
In the case of fat cells, the secretion is rarely eliminated, the
secretive process is exceedingly slow, and the oleaginous matter is
stored up and retained within the cavities of the cells themselves, the
growth of the cell membrane keeping pace with the increase in the
amount of its fatty contents.
The idea of fluidity is almost inseparably connected with our
notions of a secretion ; secretions, however, are not essentially fluid,
for there are solid secretions as well as fluid; the sebaceous matter
of the glands of the prepuce is a solid, and the urine of many ser-
pents, as the boa, is also stated to be solid. There is little doubt,
however, but that most and perhaps all secretions are fluid during the
act of their formation, and that the solidity acquired by certain of
them occurs after their perfection and elimination.
In a strictly systematic arrangement of structures, the majority of
the glands might well be described in connexion with the internal
and external integuments of the body, the skin, and mucous mem-
brane, since in very many glands, the secreting structure is contained
within, but most probably not developed from inverted processes of
these tissues. Such an arrangement of the glands, although a very
natural one as far as it goes, would yet not embrace all the glands;
the vascular and some others would be excluded from it.
The proof of the position that very many glands, and even the
most complex ones, are contained in offsets of the various modifica-
tions of mucous membrane and outer integument, observers have
stated to be derived from an examination of these organs in an
embryonic condition, when even, it has been affirmed, the most elab-
orate and varied of them may be seen as simple follicles or sacs,
springing from the general membrane covering the skin or lining the
internal cavities.
408 THE SOLIDS.
It would appear, however, from recent and trustworthy observa-
tions, that the principal glandular organs of the body have each a
separate development, and that it is only after they have been more
or less completely formed that they become attached to the surface
of the skin or mucous membrane, upon which their secretions are
poured.
Numerous divisions of glands have been proposed by different
writers: the majority of these do not require any special notice:
there is one, however, originating with Mr. Goodsir, which would
appear to be ingenious and philosophical, which deserves especial
mention. That gentleman divides glands into two types or classes;
the distinctions existing between which are founded upon observations
derived from the study of the early development of these organs.
In the first type of glandular structure, the follicles which are at
first distinct from the excretory duct, but which subsequently become
united with it, are regarded as parent cells, the granular cells con-
tained within them being secondary formations, which are continually
in process of development, springing from a germinal spot situated
either at the bottom of the follicle, if this be short, or over its entire
surface, if the follicle be tubular : in this class, the follicle is a
permanent structure.
In the second type, the follicle is also a parent cell, but is not a
permanent structure; and having attained its maturity, it bursts,
discharges the secondary cells contained within it, and finally shrivels
up, its place being supplied by other similarly organized cells.
In this type, but one gland is included — the testis.
The arrangement of glands proposed below, in a tabular form,
would appear to be one of the least objectionable, as well as the most
practical for purposes of description:
CLASSIFICATION OF GLANDS.
a UNI-LOCULAR GLANDS.
Follicles. Solitary Glands.
Stomach Tubes. Aggregated Glands.
b. MULTI-LOCULAR GLANDS.
Sebaceous Glands. Mucous Glands.
Meibomian Glands. Labial Glands.
GLANDS. 409
Glands of Hair Follicles. Buccal Glands.
Caruncula Lachrymalis. Gingival Glands.
Glands of Nipple. Lingual Glands.
Glands of Prepuce. Tonsellitic Glands.
Stomach Glands.
Tracheal Glands.
Vaginal Glands.
Uterine Glands.
c. LOBULAR GLANDS.
Salivary Glands. Mammaiy Glands.
Pancreas. Liver.
Parotid Glands. Prostate Gland.
Submaxillary Glands. Cowper's Glands.
Lachrymal Glands.
d. TUBULAR GLANDS.
Brunner's Glands. Ceruminous Glands.
Sudoriferous Glands. Kidneys.
Axillary Glands. Testes.
e. GANGLIONARY GLANDS.
COMPOCyD, SIMPLE.
Brain and Cerebellum. Ganglia of Encephalic Nerves.
Medulla Oblongata & Spinal Cord. Ganglia of Sympathetic Nerves.
/. ABSORBENT GLANDS.
Lacteal Glands. Lymphatic Glands.
g. VASCULAR GLANDS.
Spleen. Thyroid.
Supra-renal Capsules. Pituitary Body.
Thymus. Pineal Gland.
h. GERM-BEARING GLANDS.
Ovaries.
It is doubtful whether the glands admit of any strictly natural and
at the same time convenient classification. The more simple glands
pass by almost insensible gradations into the more complex, thus
leaving but few salient points available for purposes of division. The
separation of the multi-locular from the lobular glands is to a great
410 THE SOLIDS.
extent arbitrary, and is adopted simply from its convenience. Per-
haps the best division which could be proposed of those glands which
are provided with excretory ducts or openings, is into follicular and
tubular glands.
It is very probable that one of the organs introduced into the
division of lobular glands, viz : the liver, will hereafter have to be
removed from that division and placed by itself near to the vascular
glands, should some recent researches in reference to the termination
of the biliary ducts be confirmed.
It is also probable that further research will disclose the fact that
certain of those glands arranged as mucous glands do not all possess
precisely the same structure.
UNI-LOCULAR GLANDS.
FOLLICLES.
Crypts and follicles are inverted, and sometimes tubular prolonga-
tions of one variety of mucous membrane, termed compound, and to
which that of the alimentary canal, the gall-bladder, the uterus and
the Fallopian tubes belong.
In the stomach and in the large intestines these follicles are so
closely set in the membrane, that, from the mutual compression exer-
cised upon each other, they assume a more or less angular figure ; in
the small intestines there are fewer follicles, in consequence of the
great number of villi present in these, and they are not angular, but
round. These follicles, which, in the small intestines, are called the
follicles of Lieburkuhn, are met with under two very different condi-
tions; in each of which they present a very distinct appearance, being
in the one case — that is, in their perfect state — lined by epithelium,
and in the other being destitute of this epithelium. (See Plate L.
figs. 1. 6.)
The epithelium lining the follicles of the alimentary canal, is of the
same kind as that which covers the inter-spaces between the follicles,
and is of the conoidal variety. It lines the entire follicle with a beau-
tifully regular layer of united epithelial scales, which are so large that
they nearly fill up the cavities of the follicles, a small circular channel
only being visible in each: this is usually occupied by the mucus
secreted by the cells, and appears at the mouth of each follicle as a
mere depression, surrounded by a circle of radiating epithelial scales.
To see the epithelium in the follicles of the human stomach, and
even to see the follicles in the mucous membrane of this organ at all,
GLANDS. 411
requires that it should be examined immediately after death, as the
lapse of a few hours is sufficient to allow of the action of the gastric
juice to such an extent as to dissolve the follicles entirely.
The follicles dip into the thickness of the mucous membrane to a
variable extent in the small and large intestines; their extremities
reach nearly to the sub-mucous cellular tissue, and in the lower part
of the rectum they are much elongated, and continued for some
distance into the sub-mucous fibrous tissue between the mucous and
muscular coats; the follicles usually terminate in rounded and some-
times even in dilated and bifurcated extremities! (Plate L. j%. 7.)
The object attained by these innumerable follicular inversions of
the mucous membrane of the stomach and intestines is obvious, viz :
a greatly extended surface for secretion.
The mucus with which the intestinal canal is so abundantly pro-
vided, is chiefly secreted by the epithelium contained in these follicles.
Todd and Bowman thus describe the epithelium of the stomach cells
in the "Physiological Anatomy:" ''They [the epithelial particles]
seem to lie in a double series, the deeper being in course of develop-
ment, while the more superficial is in course of decay. It has appeared
to us that each particle, when arrived at maturity, has, besides the
nucleus, granular contents enclosed, and that at a subsequent period
the granular contents escape at the free extremity by a dehiscence or
opening of the wall, at that part, having the transparent husk with its
nucleus subsisting for some time longer. The clear structureless
mucus, which is almost always found occupying the cells and cover-
ing the surface of the membrane, seems to be the altered contents of
these particles after their escape ; for the uniform existence of a minute
cavity in the centre of it, when it fills the cells, shows that it has
oozed out from every part of their wTall so as gradually to fill them up."
The ridges or spaces between the follicles of the stomach and large
intestines in the human subject are occupied with a plexus of vessels
larger than capillaries (see Plate U.fcg. 1) ; these are situated on the
deep surface of the basement membrane, while the epithelial scales
are upon its superficial surface : in the cat, and many other animals,
the inter-follicular spaces, instead of being occupied by a plexus of
vessels, contain only a single vessel, which freely inosculates with the
neighbouring vessels, thus mapping out the spaces between the follicles
into somewhat irregular hexagons. (See Plate LI. fig. 2.)
412 THE SOLIDS
STOMACH TUBES.
The tubes of the stomach are prolongations of the basement mucous
membrane lining the follicles of that organ. (See Plate h.figs. 3, 4, 5.)
These tubes take a parallel course, end in irregularly-dilated extrem-
ities, are arranged in sets of three, four, or five tubes, each of which
corresponds with a follicle, and represents the number of tubes which
open into that follicle: it is only however, near their entrance into
the follicles that they are thus parcelled out: at their termination they
would appear to be independent of each other, and to be separated by
equal intervals, as represented in Plate lu.Jig. 3.
The stomach tubes, unlike the, mucous follicles, are filled with
spheroidal or glandular epithelial cells: these cells, however, do not
quite fill up the cavity of the tubes, but leave in the centre of each a
channel or canal, along which the fluid secreted by the cells flows,
until at last it reaches the follicle into which it is poured.
The fluid secreted by these cells is, doubtless, the true solvent or
gastric fluid.
The tubes I find to exist not merely in the stomach, to which they
are generally described as exclusively belonging, but also in the upper
part of the duodenum, which shows that in the human subject this
portion of the intestine is to be regarded as a kind of second stomach.
I have observed the occurrence of these tubes more than once, both
in the duodenum of man as well as of other mammalia.
The fact of the mucous membrane lining the duodenum being
frequently dissolved some hours after death, in the same manner as
that of the stomach, would in "itself lead to the inference that these
tubes were present in the upper part of that division of the aliment-
ary canal.
Messrs. Todd and Bowman figure the tubes as more or less
branched previous to their entrance into the follicles, an observation
which I can confirm: these gentlemen also thus describe a modifica-
tion of the follicles and tubes near to the pylorus: "Here, in many of
the lower animals which we have examined — for example, in the dog,
and it may with probability be inferred, in man also — a change occurs
in a very gradual manner, but evidently of an important kind. The
membrane is of a paler tint, and its cells seem not to terminate at once
in the true stomach cells already described, but are prolonged into
much wider cylindrical tubes, lined with the same columnar epithelium,
and descending nearly or altogether to the deeper surface of the com-
GLANDS. 413
pound membrane. For the most part, these prolongations of the
celis — or, as we shall term them, pyloric tubes — end, at length, in very
short and diminutive true stomach tubes; but we have likewise found
them terminating in either flask-shaped or undilated extremities, lined
throughout with the sub-columnar variety of epithelium."
The stomach tubes are each surrounded by a plexus of vessels.
Sec Plate LXXIV., figs. 1 — i.
FALLOPIAX AND L"TEREN"E TUBES.
Tubes somewhat similar to those of the stomach exist, according to
the observations of Mr. Bowman, in the mucous membrane of the
Fallopian tubes and stomach.
"The lining membrane of the Fallopian tubes, as well as that of the
uterus, is of a compound nature, especially during gestation, and con-
sists of tubules arranged vertically to the general surface. It is to be
observed that the cilia only clothe the general surface, and that the
epithelium lining the tubules is spheroidal or intermediate between
that and the prismatic. It is a form of the glandular variety, and
bears no cilia.*
SOLITARY GLANDS.
The solitary glands are scattered irregularly over nearly the whole
surface of the same small and large intestines ; they vary consider-
ably in size — the larger glandulae being found principally in the lower
portion of the large intestines, and admitting of easy recognition
without the aid of lenses; while the smaller glands, situated in the
lesser bowel, are scarcely visible, except in states of disease, when
their cavities are filled with secretion. Plate LI1. fi&. 6, is a drawing
of these glands, as they appeared in a case of muco-enterite in one
of the small intestines, while Plate LI. Jig. 6, is a representation of
them as found in the larger bowel in a case of English cholera
in a child.
These glands are simple sacs or cells, filled with a fibrinous fluid,
containing imbedded in it innumerable spheroidal and granular cells,
somewhat smaller than ordinary mucous corpuscles.
I have observed these glandulae both with and without central
orifices; these have been more frequently absent than present; hence
it is very probable that their normal condition is that of a closed cell,
and that when these cavities become filled with secretion, thev rupture,
and thus permit their contents to escape, the orifice subsequently
closing up again.
* Cyclopedia of Anatomy and Physiology, Art. "Mucous Membrane," voL iii.
414 THE SOLIDS.
Not unfrequently, these glands in certain animals, but not generally
in man, are observed to be surrounded by a circle of short and tubu-
lar caeca; these by some observers are regarded as follicles of
Lieburkuhn, and it is uncertain whether their bases communicate
with the cavities of the glands or not, but it is generally stated not to
communicate with the interior of the glandules.
The distribution of the vessels around these glands presents nothing
remarkable.
AGGREGATED GLANDS.
The aggregated, agminated or Peyer's glands, are present in the
lower portion of the ilium only.
They occur in patches of various sizes, each of which is made up
of a considerable number of distinct glandules, having much the
same structure, form and volume, as the solitary glands, an aggrega-
tion of which they may be considered to be. These patches may be
readily recognised without the assistance of glasses.
In the "glandulae aggregatae," central apertures are occasionally
present, and they are not unfrequently surrounded by the short
tubular caeca already spoken of: the inter-spaces between the gland-
ulae in the human subject are very generally covered with villi. The
size and limits of these glands may be best determined by injection.
When examined with glasses, as they lie in the mucous membrane
in situ, they appear rounded and flat, presenting many dark spots,
the nature of which is not understood : when viewed sideways, they
are seen to be really of a flask-shape, the narrow extremity of the
flask being turned towards the surface of the mucous membrane.
(Plate 111. figs. 3, 4.)
In inflammation of the mucous membrane of the ilium, a frequent
concomitant of low fevers, these glands are often found to be entirely
eaten away, but sometimes they are only so far eroded as to present,
in place of closed glands, a number of open cells or follicles.
MULTI-LOCULAE GLANDS.
SEBACEOUS GLANDS.
The sebaceous glands are very generally distributed over the
surface of the body, probably not less so than the sudoriferous glands,
there being but two situations in which they are stated to be absent
GLANDS. 415
viz: the palms of the hands and the soles of the feet. On all other
surfaces of the body the two kinds of glands are constantly associated
together, the sudoriferous being much more numerous than the seba-
ceous glands.
They are found especially more or less deeply imbedded in those
portions of integument which are copiously clothed with hair, as the
scalp, whiskers, beard, axilla, pubis, scrotum, and perineum. They
also exist, however, in abundance in certain situations not usually
invested with hair, as in the integument of the forehead, face, and
nose, in the meatus auditorius externus of the ear, and for a certain
distance up the anterior openings of the nares: those situated around
the nipple of the female are particularly large, while those of the
prepuce are not merely of considerable size, but yield a solid and
unctuous secretion of a peculiar and penetrating odour.
Those glands which exist in situations which are naturally clothed
with hair, always open into the hair follicles; while those present in
parts not furnished with such a covering, yet nevertheless open into
follicles, which, although from the absence of hairs they cannot be
called hair follicles, must yet not be regarded as essentially distinct
from hair follicles, since they in some cases do really contain hairs.
As there are varieties of sebaceous matter, so are there sebaceous
glands which differ structurally from each other; thus, the cerumen
glands of the ear present a conformation typically distinct from all
other sebaceous glands, belonging to the tubular type of glands, with
which they will be described.
There are characters, however, in the possession of which all
sebaceous glands agree, save, perhaps, the cerumen glands, and these
are in the semi-solid nature of their secretion and in the mode of its
formation and elimination.
The secretion of the sebaceous glands, like other secretions, is
formed within the cells, which are very large, and in which it exists
in the form of little spherical and shining particles of various sizes ;
these cells, when filled with the secreted matter, are thrown off with-
out rupture from the glands in which they have been formed, probably
by the development of fresh cells behind them, so that in general, the
sebaceous secretion consists of an aggregation of such eliminated
cells. Some few of the cells, however, do burst, and allow of the
escape of their contents.
The sebaceous cells, like other secreting cells in an early stage of
development, are granular and nucleated.
416 THE SOLIDS.
In the character of their secretion, the sebaceous glands exhibit
considerable affinity with the mammary glands. The milk globules,
however, are formed without the cells, and not within them, as is the
case in the sebaceous glands.
The sebaceous glands, exclusive of the ceruminous, manifest con-
siderable variety in size, form, and arrangement. They may be thus
arranged: first, the Meibomian glands; second, the glands of the
Hair Follicles, the hairs being in some cases present in the follicles,
and in others absent from them; third, the glands of the Nipple;
fourth, the glands of the Prepuce: and fifth, the glands of Carunculee
Lachry males.
Meibomian Glands.
The Meibomian glands are situated on the inner surface of the
eyelids, between the conjunctiva and the tarsal cartilages; they are
of an elongated form, and disposed in a vertical manner.
The number of these glands in the two eyelids is usually not less
than forty; in one instance I counted eighteen in the upper eyelid,
and twenty-two in the lower. Their general form and arrangement
differs somewhat in the two eyelids; thus, in the lower, they are of
nearly equal length, and are arranged in a parallel manner, while in
the upper they are much longer, almost as long again, their origins
describing an arc ; and in place of being disposed parallelly, they
radiate from each other. These differences depend upon the corres-
ponding differences in the size and form of the two eyelids.
Each gland consists of a number of follicles or sacs which open
into a central canal, which pierces the conjunctival membrane at the
margin of the tarsal cartilages. The follicles are usually filled with
cells, which may be seen through their wTalls. These cells present a
bright and shining appearance from the oily nature of their contents.
(See Plate Ull.fig. 2.)
Glands of Hair Follicles.
The external surfaces of the body, with few exceptions, the palms
of the hands and soles of the feet being the principal of them, are
covered with the hair follicles, which are placed at tolerably regular
distances from each other, and the apertures of which are visible
even without the aid of glasses.
The hairs which issue from these follicles differ in character accord-
ing to their situation: those of the scalp being long and fine; those of
GLANDS. 417
the beard, &c, short and thick; while those clothing the general sur-
face of the body are not merely short, but also exceedingly slender.
In certain situations, the hair follicles are frequently without hairs,
as on many parts of the face; this, however, is the exception rather
than the rule, as very fine hairs are generally present over the entire
surface of the face.
It is into these hair follicles that almost all, if not all, sebaceous
glands open.
The sebaceous glands of the hair follicles consist of several distinct
cells or sacculi, each of which has a separate excretory duct ; two or
more of these ducts — there being sometimes three, four, or five — open
into one common duct, which last opens upon the sides of the hair
follicles: there are usually two, but sometimes more of these common
ducts, and very frequently several of the primary excretory tubes
open directly into the hair follicle. The ducts are large, and usually
straight; but occasionally, like those of the sudoriferous glands, they
are slightly spiral. (See Plate hill. Jig. 1. 3.)
Those sacculi which open into the hair follicles by distinct ducts
are to be regarded, as separate glands. In the hair follicles of the
scalp, the glands are usually binary.
The glands of the hair follicles are not confined to the external
surfaces of the body, but are continued for a certain distance along
several of the outlets. Thus, they occur in the lower part of the
anterior openings of the nares, in the meatus auditorius externus, in
the palpebral conjunctiva, in the caruncula lachrymalis, in the vulva,
and on the interior surface of the prepuce.
The sebaceous glands vary greatly in size, being, in certain situ-
ations, much larger than in others, as in the eyelids, ears, nose, around
the nipples, especially of the female, and on the inner surface of the
prepuce.
The cells contained within the ordinary sebaceous glands differ, in
no respect, from those of the Meibomian glands already described.
It is in the hair or sebaceous follicles that the well-known parasite, the
Steatozoon Folliculorum, whose economy has been so well described
by Mr. Wilson, is found ; it being placed in these in an inverted posi-
tion, the head being turned inwards, as though the animalcule had
crept into the follicles from without. Many of the follicles frequently
contain more than one parasite.
27
118 THE SOLIDS.
Caruncula Lachrijmalis.
The caruncula lachrymalis is usually described as formed of a single
large sebaceous gland : it is not so, however, but is constituted of a
considerable quantity of mixed fibrous tissue and of blood-vessels, in
the midst of which several, usually four or five, distinct sebaceous
glands are imbedded.
These glands, like other sebaceous glands, also open into follicles,
which are certainly hair follicles, although, in the human subject, they
do not usually contain hairs. That they are really hair follicles, how-
ever, is proved by the fact that in the sheep, minute hairs do constantly
issue from them.
Glands of Nipple.
The sebaceous glands imbedded in the integument which forms the
areola around the nipple, so conspicuous in the female, differ from
other sebaceous glands principally in their larger size, which allows
of their being readily perceived without the assistance of glasses.
Glands of Prepuce.
The glands of the prepuce are also remarkable for their large size,
as well as for the peculiar characters of the secretion which they
furnish: one of these being its semi-solid consistence; a second, its
penetrating and remarkable odour
MUCOUS GLANDS.
The great agents in the secretion of mucus are the cells contained
in the follicles with which all compound mucous membranes are
furnished ; there is, nevertheless, a description of gland very generally
distributed, differing anatomically from the follicles also called mucous,
and which is, in like manner, supposed to furnish a mucous secretion.
It is, however, very probable that as there are structural differences
between the two, so are there differences in the nature of the secretion
elaborated by them.
Before entering into a description of the mucous glands, it will not
be out of place to present to the reader the results of some additional
researches on the structure of mucous membranes: at a former page
of this work, it was stated that mucous membranes may be divided
into simple and compound, according as they contain follicular invo-
lutions, or are destitute of such inverted processes ; and that the com-
GLANDS. 419
pound membranes were that of the alimentary canal from the cardia
downwards, of the gall-bladder, and of the uterus and Fallopian ubes,
according- to Bowman. Further observations have, however, shown
me that on the one side the mucous membranes of he mouth
(including that which lines its roof, which invests the tongue, and
which covers the tonsils, uvula, and epiglottis), of the oesophagus
down to the cardia, of the vagina and neck of the uterus, of the vesiculae
seminales, as well as the Schneiderian membrane, are also compound;
while, on the other, the mucous membranes of the Eustachian tubes, of
the trachea, and bronchial tubes, of the bladder, and of the unimpreg-
nated uterus, and Fallopian tubes, are simple mucous membranes.
The follicles of the mouth are somewhat large, scattered, and mostly
simple ; those of the oesophagus are small, and not unfrequently divided
into branches near their extremities; the follicles of the vagina resem-
ble somewhat those of the oesophagus ; but are much more branched,
very many of the follicles terminating in several offsets, and becoming,
in fact, perfect multi-locular glands : the follicles of the Schneiderian
membrane are the largest hitherto noticed, and appear to be simple
inversions of the membrane.
It has been stated that the mucous membrane of the uterus and
Fallopian tubes is simple; in which respect there is a difference
between the observations of the author and those of Mr. Bowman.
Considerable pains have, however, been taken to arrive at the truth ;
and it is conceived that the mucous membrane of the parts cited
affords one of the best examples which could be given of a simple and
delicate mucous membrane. The membrane covering the lips of the
uterus and lining the orifice of that organ is, however, like that of the
vagina, follicular — the follicles in the latter situation being particu-
larly large; and it is these follicles which yield the thick and tenacious
mucus which usually more or less completely plugs up the uterine
orifice.
Mucous glands occur in very many and different localities, in sev-
eral of which they have received distinct names, taken from the parts
or situations in which they have been found. Thus, we have labial,
buccal, tonsillitic, lingual, and tracheal glands ; following up a similar
kind of nomenclature for these glands, we might add to this list
Eustachian, palatine, pharyngial, and bronchial glands; also, glands
of the uvula.
In the roof of the mouth the mucous glands are very numerous,
forming almost one continuous glandular layer, provided with many
420 THE SOLIDS.
orifices, disposed at tolerably regular distances from each other : they
are also numerous in the tonsils, but much less so in the uvula : on
the dorsum of the tongue, mucous glands occur but very sparingly,
and mostly near the root of this organ.
There are some few situations in which mucous glands have been
described as present, in which they would appear to be entirely absent ;
as on the margins of the gums, where they have been called gingival,
in the uterus and vagina, where they have been named uterine and
vaginal glands: in the stomach, also, where they are known as the
lenticular glands, they are very frequently wanting.
There are also certain glands which have not been generally placed
in the category of mucous glands, which, nevertheless, are really
structurally identical with them: of this nature, are Brunner's and
Cowpers glands.
From the preceding observation, it follows that Brunner's and
( -owper's glands should be described with the other mucous glands :
it will, however, be seen hereafter that the former present certain
resemblances to the tubular, and the latter to the lobular glands.
Messrs. Todd and Bowman* regard the mucous glands as identical
in structure, and probably in function also, with the salivary glands:
that they are not salivary glands, however, may be shown, first, by
the anatomical differences which may be pointed out as existing
between mucous and salivary glands, as well as, secondly, by the
fact that mucous glands occur in situations — as in the trachea, &c. —
where they could serve no purpose as salivary glands. Mucous
glands occur in two forms: a simple and compound form. In its
simple or simplest form, a mucous gland consists of a single duct, in
communication, at its origin, with a saccated membrane, each saccu-
lus of which forms an imperfect follicle. In its compound form, it
consists of several ducts, each of which, at its origin, is in like
manner in connexion with a bunch of incomplete follicles.
The chief anatomical characters which distinguish mucous glands
from the salivary, to which, indeed, they bear considerable resem-
blance, depend upon the fact that, in the mucous glands, the follicles
are incomplete; that is, they open into each other, and into a common
central cavity, from which the single efferent duct proceeds ; while
in the salivary glands each follicle is a distinct body of a rounded or
oval form, and provided with a small primary efferent duct.
Independent of the important differences indicated in the preceding
* Physiological Anatomy, p. 1 82.
GLANDS. 421
paragraph, there are others, viz: the larger size of the follicles of the
mucous glands, and the coarser and firmer texture of the membrane
which constitutes their parietes.
That the follicles do really communicate with each other, is proved
by the numerous circular apertures which they frequently present,
and which reminds one of those of the air-cells of the lungs. (Plate
LIILj^. 4.)
The epithelium contained within the follicles is very small, the
majority of the cells being spherical.
The membrane of the follicles would appear to be fibrous, and is
sufficiently resisting to preserve their form under ordinary pressure
and manipulation.
BRUNNER'S GLANDS.
These glands have been already referred to under the head of
mucous glands, with which they are structurally identical.
I was led, for a short time, into the error of arranging them with
the tubular glands, in consequence of observing that each of the
larger glands of Brunner was generally furnished with several tubu-
lar ducts; and this led me at first to infer that they were formed
entirely upon the tubular type, which is not the case.
In those instances in which more than one duct proceeds from
what appears to be a single gland, this gland is not really simple, but
compound ; that is to say, it is formed of several clusters of follicles
held together by fibrous tissue, and from each of which a separate
efferent duct proceeds.
The glands of Brunner occur only in the duodenum, and occupy
usually the upper two-thirds of that intestine: their number and
extent of distribution vary, however, in different subjects.
For further particulars, see the description of the Mucous Glands.
COWPER'S GLANDS.
Cowper's, or the anti-prostatic, glands are, as already mentioned,
mucous glands, being the largest examples of this description of gland
met with in the human body.
The description given of these glands by authors in general, their
large size and their apparent constitution of lobules, were the reasons
which led to their being temporarily classified with the lobular glands.
The description given of the mucous glands applies in every
respect to these.
422 THE SOLIDS.
A knowledge of their true structure and relationship explains their
use, concerning which many vague conjectures have been hazarded.
LOBULAR GLANDS.
SALIVARY GLANDS
The salivary glands include the parotid, sub-maxillary, and lingual
glands, together with the pancreas.
These several glands resemble each other very closely in structure,
as well as in the characters of the secretions furnished by them.
The salivary glands consist of lobes and lobules, on the surface of
which the blood-vessels ramify ; the lobes are made up of the lobules,
and the lobules themselves consist of follicles of a rounded or oval
form, and each of which is furnished with a minute efferent duct,
which, uniting with the other ducts of the same size, forms other
larger ducts, and these, uniting again with others of still larger calibre,
at length form, by their union, the main excretory tube of these
organs. (Plate LIV. figs. 1, 2, 3, 4, 5.)
The follicles contain numerous minute granular cells ; and those of
the pancreas, in addition, frequently many shining globules of an
oleaginous character.
Such is a brief description of the salivary glands in their adult
form : in their embryonic condition, however, they do not consist of
lobes and lobules, but the terminal efferent ducts end in single folli-
cles, which afterwards become multiplied, until at length clusters of
them appear — the incipient lobules. (Plate LIV. figs. 1, 2.)
The structure of these glands may be readily followed out without
the aid of injection.*
* It will be observed, that the above description of the salivary glands agrees
closely with that ordinarily given. An examination of these glands, instituted since
this description was in type, has convinced me that they approach in organization
very nearly to the mucous glands, of which they are to be considered as a variety.
The salivary glands differ indeed from the mucous in the particulars already men-
tioned, viz : in the less size of the follicles, and in their more complete shape, but
nevertheless are formed upon a similar type of organization. The efferent duct with
which each of the follicles of the salivary glands is said to be furnished is so short,
that it in very many instances scarcely deserves the name of such; the general
arrangement is that of a number of follicles, almost sessile, clustering around the
terminations of the salivary ducts.
GLANDS. 423
LACHRYMAL GLANDS.
These glands resemble the salivary in all essential structural partic-
ulars : they are, however, separated from them in consequence of the
difference in the character of the secretion which they furnish.
MAMMARY GLANDS.
The mammary glands do not require any lengthened description,
since they also are formed upon precisely the same type as the sali-
vary and lachrymal glands.
The principal structural difference has reference to the efferent
ducts. Each salivary gland is furnished with but a single excretory
duct, while to each mammary gland there are as many as eight or
ten ducts which open on the apex of the nipple: the ducts of the
mammary gland are also remarkable for their great capacity, for it is
in them that the milk principally collects when it is allowed to
accumulate.
When the follicles of a mammary gland in an active state are
examined, vast numbers of milk globules, of various sizes, will be per-
ceived within them; and lying in the midst of these, the small gran-
ular secreting cells will be seen: these, however, do not contain milk
globules, from which it follows that the milk corpuscles are not formed
within the granular cells, but external to them, although still within
the cavity of the follicles. (Plate ~LYV.Jigs. 3, 4, 5.)
Mammary glands exist in the human male as well as female breast,
the essential structure being the same in both, as proved by the many
cases now on record, in which infants have been suckled by men.
In childhood and old age the mammary glands consist of white
fibrous tissue, in the midst of which traces only of the follicles can be
perceived.
Numerous lacteals arise from the neighbourhood of the follicles; by
these, the more watery parts of the milk are absorbed when this is
retained for any length of time within the breast, and in this way the
distension of that organ is from time to time relieved.
LIVER.
The liver has been described as consisting, like the other glands of
the lobular form, of lobes, lobules, and follicles or acini; and, indeed,
in some of the lower animals, this organ has such a constitution. It
has, nevertheless, recently become a matter of very great doubt
424 THE SOLIDS.
whether in the Mammalia, at least, the same type or organization
prevails, and whether the structure of this gland in this class of animals
is not of a totally different kind.
The mammalian liver consists indeed of lobes and lobules, but the
question is as to the existence of the follicles or acini furnished with
their efferent ducts.
In the adult liver, the division into lobes, even, is essentially arbi-
trary; so that, hi fact, it is of lobules alone that the liver is entirely
composed.
Lobules. — The lobules of the liver are aggregations or masses of
granular or secreting cells, of a more or less angular form, first resting
upon, and then traversed by, branches of the hepatic vein, and enclosed
on all sides by a process of the capsule of Glisson. The intervals
separating the sides of two lobules from each other are called inter-
lobular fissures, and those which exist where three or more lobules
touch each other, inter-lobular spaces.
These lobules, for the most part, are perfectly distinct from each
other; nevertheless, not unfrequently two of them are more or less
united together, as is seen especially on the surface of the liver, and
in preparations in which the hepatic system of vessels has been
injected. (Plate lAY.fig. 6. Plate LY.fig. 1.)
The lobules of the liver are of sufficient size to be easily recognised
with the unassisted sight: they vary, however, in dimensions, not
merely in the liver of different animals, but likewise in that of the
same: in some animals, also, as in the rabbit and pig, their form, as
well as their size, may be clearly defined; and in these they are
evidently angular. (Plate LV. fig. 1.)
Such is a brief description of the lobules of the liver : the supposed
follicles or acini are nothing more than the intervals between the
meshes of the capillary vessels which ramify through the substance of
the lobules, and the outlines of which vessels may be readily followed,
even without the aid of injection, their course being indicated by a
number of dark lines.
Mr. Kiernan supposed that the acini were really follicles, and that
they occupied the spaces which he conceived existed between the
meshes of his lobular plexus of biliary ducts.
The secreting apparatus of the liver consists not only of lobules and
their component cells, but also of biliary ducts and gall-bladder.
Biliary Ducts. — In his admirable paper on the liver, inserted in the
"Philosophical Transactions" for 1833, Mr. Kiernan describes the
GLANDS. 425
biliary ducts as terminating in the substance of the lobules in a com-
plicated net- work of minute biliary vessels, which he termed the lobular
biliary plexus. Much doubt, however, has recently been cast upon the
accuracy of this description, notwithstanding that it has received the
confirmatory testimony of very many high microscopical authorities.
The first observer who, I believe, expressed doubts of the existence
of a lobular biliary plexus was Mr. Bowman, to whose numerous
microscopical researches science is so much indebted.
More recently still, Dr. Handfield Jones, in a paper "On the Secre-
tory Apparatus of the Liver,"* has not merely expressed the same
doubts, but has entered fully into the reasons on which his opinion
is based.
Dr. Jones founds his belief of the non-existence of a lobular biliary
plexus upon the following observations :
" First, the non-existence of basement membrane in the interior of the lobules,
which, in common with Mr. Bowman," he writes, "I have been unable to detect; yet,
were this simplest constituent of a duct present, it could hardly escape notice, espe-
cially as hi other glands it admits of being readily demonstrated; at the broken margin
of a lobule it may be well seen that the broken extremities of the linear series are
quite free, and exhibit no trace of any containing membrane. Secondly, if the margin
of a lobule be carefully examined, where it forms the sides of a fissure, the basement
membrane may often be clearly seen, and through its transparent texture the terminal
cells of the linear series are easily distinguished, resting against and contained by it.
Now, were the membrane inflected to form lobular ducts, surely some indentation or
irregularity would be visible at the margin of the lobule, but I have often traced the
outline carefully without observing any such. A third proof is supplied by the result
of some experiments which I made on rabbits. I tied the duct. com. choled., and
shortly after death, which took place at periods varying from two to four days, I
examined their livers: these organs were found to be beset on the surface and
throughout their substance with numerous spots of deep yellow colour, evidently
produced by accumulation of bile; a section of these spots, examined under the
microscope, showed that they were very partial, never extending throughout the
whole of a lobule, but frequently situated in two or more adjacent; their outline was
always well defined, and not the slightest appearance of a distended plexus of ducts
could be observed. This last evidence appears to me conclusive. I can hardly con-
ceive that, if any plexus of anastomosing ducts existed, the accumulation of bile
should take place in definite spots, and those not always situated in a single lobule,
but in two or three adjacent."
Of the proofs of the existence of a lobular biliary plexus, supposed
to be derived from injection, it may be remarked, that these are, in all
probability, fallacious, the injection escaping from the extremities of
the biliary ducts, and passing into, generally, branches of the portal
* Philosophical Transactions, 1846.
426 THE SOLIDS.
vein from which it extends irregularly into the lobular capillary plexus,
and it is this plexus, filled with injection from the biliary duct, that
Mr. Kiernan, it appears to me, took for a lobular biliary plexus. It
still, however, must be regarded as a singular circumstance that the
injection should so generally pass, after its escape from the ducts, into
blood-vessels, in place of becoming extravasated around the apertures
of the ducts from which the injected material has escaped.
Presuming it, then, to be concluded that there is no lobular biliary
plexus, let us next inquire in what manner the biliary ducts do really
terminate.
From the further researches of Dr. Handheld Jones, contained in
a recent paper communicated to the Royal Society, and entitled "On
the Structure and Development of the Liver," it would appear that
the biliary ducts terminate in the vertebrate series of animals in the
inter-lobular fissures and spaces in closed and rounded extremities.
(Plate LVII. fig. 1.)
If a branch of the hepatic duct be taken up with the forceps, it may,
by delicate manipulation, be dissected out from the surrounding paren-
chymatous tissue. A branch thus prepared, when placed under the
microscope, will be seen to be composed of numerous ramified biliary
ducts of various sizes : the extremities of a majority of these are even
broken off; but several are evidently entire, and these are rounded,
as represented in Plate LVII.^g-. 1.
These ducts are not simple tubes, formed of basement membrane,
but are lined by a regular layer of epithelial scales : these serve to
secrete the mucus, which partly occupies them ; and their presence
accounts for the great difficulty experienced in getting the injection
to flow along the ducts.
The experiment of dissecting out a branch of the hepatic duct from
the parenchymatous tissue of the liver is most readily performed in
the soft livers of most fish; as the plaice, sound, &c; but it may be
also effected in the livers of the various mammalian animals.
The author has repeatedly examined branches of the hepatic duct
thus prepared, and his own independent observations fully corroborate
those of Dr. Handheld Jones, to whom for his very carefully con-
ducted inquiries on the intimate structure of the liver, physiological
anatomists are much indebted.
The mucous membrane lining the larger hepatic duct is, according
to the observations of Mr. Kiernan, follicular.
Secreting Cells. — The secreting structure of the liver, as of all
GLANDS. 427
other truly glandular organs, is cellular, the majority of the cells being
perfect, and consequently nucleated, but some few consisting of nuclei
only, the most essential element of the cell. Each cell may contain
more than one nucleus.
These cells are disposed in series, which radiate from the centre of
each lobule, occupied by the lobular hepatic vein : the radii are not
formed of single rows of cells placed simply end to end, but the cells
frequently partially overlap each other. (Plate LIV. fig. 6.)
This linear disposition of the cells would appear to be determined
by the radiated arrangement of the vessels which proceed on all sides
from the central hepatic vein.
Dr. Jones considers that this arrangement of the cells is connected
with the secretion of the bile, and that it facilitates the transmission of
this fluid from the centre to the circumference of the lobules : when
it has reached this, it is discharged into the inter-lobuiar fissures and
spaces, to be absorbed into the ducts by an endosmotic action deter-
mined by the denser mucoid fluid contained within them.
Dr. Handfield Jones has also observed that frequently the cells are
not merely disposed in linear series, but that they likewise coalesce
with each other by their opposed margins, whereby the cavities of
several cells are made to communicate with each other. This union
of the cells Dr. Jones considers to be intended to facilitate still further
the transmission of the bile along the series of cells; and he seems
disposed to regard it, if not absolutely essential to this transmission,
yet as of very general occurrence. There can be no question, how-
ever, but that, in the great majority of cases, the bile is passed from
cell to cell, independent of any such union : this is proved by the ex-
ceeding rarity of the occurrence of rows of cells united in the manner
described and figured by Dr. Jones.
The same accurate observer considers that the first secretion of
bile takes place in the most central cells of the lobule, and that this
fluid is accumulated in the greatest quantity, and its elaboration per-
fected, in the marginal cells of the lobule. These opinions are founded
upon the following experiments and observations : thin sections of the
liver of a rabbit being examined, the ductus communis choledochus of
which had been tied twenty-four hours before death, it was manifest,
in almost every instance, that accumulation of bile had taken place
in the centres of the lobules, as indicated by a yellow zone of some
width surrounding the intra-lobular vein. Now this case, in the
opinion of Dr. Jones, presents the earliest effect of interruption to the
428 THE SOLIDS.
flow of the secretion; and the appearance described seems to point out
the exact spot where the secretion had its origin, viz : in the com-
mencement of the rows of cells surrounding the central axis of the
lobule, as represented by the lobular hepatic vein : again, in many
livers, a remarkable difference may be observed in the condition of
the marginal cells and those placed more centrally; while the latter
have appeared of their usual pale or light yellow colour, and have con-
tained but one or two minute oil globules, the former have presented
a darker and more opaque appearance, arising from the presence of
numerous oil globules.
These observations, especially when considered in connexion with
the mode of termination of the bile ducts, render it almost certain that
the secreting process reaches its termination near the margin of the
lobule.
Dr. Jones recognises an active and a passive condition of the lobules
of the liver, and thus describes the differences in the appearances of
the margins of the lobules in the two states:
" The appearance which the margin of a lobule presents when the process of secre-
tion has been proceeding actively, differs much from that which is observed when the
lobule, so to speak, is quiescent: in the latter ease, as I have described it. the margin
is well defined, and bounded by a distinct basement membrane; while the terminal
cells of the linear series contain few and minute oil globules, and do not appear to
project outwards in any degree: in the other case, the margin of the lobule has an
opaque cloudy appearance from the multitude of oil globules. Several cells are seen
projecting into the cavity of the duct, giving the wall occasionally a tuberculated
appearance : these cells contain oil globules, and their wall is sometimes so extremely
delicate as to be barely perceptible even under a high power. Very many oil globules
are also seen, which lie evenly in contact with the sides and floor of the duct: it is
difficult to determine whether these have escaped from their cells or not: it seems
probable, however, that they are for the most part free, having recently been liberated
by the solution of their cell wall. The margin of a lobule, in the condition now
described, presents no trace of basement membrane; the cells themselves form the
wall of the ducts, preserving still the general outline: it seems, therefore, certain that
the basement membrane is only a temporary structure, which disappears when the
cells are actively discharging their contents. A forcible and instructive contrast to
the above condition was exhibited by a liver which I examined, which was in an
advanced state of fatty degeneration: in this the linear arrangement of the cells was
lost; they lay confusedly together; and were gorged with their fatty contents; the
margin of the lobule, far from exhibiting any tendency to discharge the retained secre-
tion, was invested, and, as it were, closely bound by a membrane, not of the delicate
transparent texture of the basement tissue, but much more opaque, and closely resem-
bling the semi-fibrous aspect of thin layers of false membrane."
GLANDS. 429
With respect to the dissolution of the membrane surrounding the
lobules at the period of the most active secretion of the bile, it may be
remarked that it is a matter of very great question whether this is either
a constant and necessary occurrence, or even a very frequent one.
Gail-Bladder. — The gall-bladder is composed of an outer, strong,
fibrous tunic, and an inner mucous one : this latter has a honeycomb
arrangement, and is of the follicular type: the larger meshes, which
are plainly visible to the unaided sight, are divided by ridges of mem-
brane into four or five other spaces or depressions of irregular size and
form, also discernible without glasses : and these again are still further
sub-divided into other cells very numerous, and which are only to be
seen with the aid of the miscroscope. It is these last which constitute
the follicles of the mucous membrane of the gall-bladder, which differ,
however, greatly from the ordinary tubular follicles of compound
mucous membranes, being simple cells or depressions formed by the
plaited and ridged arrangement of the membrane of the gall-bladder.
The follicles in the hepatic duct, and also in the inner tunic of the
vesiculee seminales, would appear to be of the same character.
If air be inserted, by means of the blow-pipe, beneath the mucous
coat, the latter will be thrown up into lobes, each of which corresponds
with one of the larger honeycomb cells: this fact shows that the
mucous membrane of the gall-bladder is bound down to the fibrous
tissue beneath, principally in the intervals between the cellular depres-
sions alluded to.
Injection thrown into the ductus communis choledochus very
frequently reaches the coats of the gall-bladder : this fact affords an
interesting and striking proof that the vessels ordinarily injected from
the common hepatic duct are not biliary, for it is generally acknowl-
edged that biliary ducts do not exist in this situation — a conclusion
to which one, without hesitation, arrives, on reflecting that in such
a situation they could serve no possible purpose.
General Remarks. — Should the foregoing account of the mode of
termination of the biliary ducts be correct, of which scarcely a rea-
sonable doubt can be entertained, it is evident that in the vertebrate
class of animals, at least, the liver is not of the follicular type, and
that in them this organ should be separated from those glands formed
on the follicular type. In the fact of the secretion making its way
into closed vessels, the liver clearly manifests an intimate and essential
relationship with the vascular glands.
The liver, then, in the vertebrate series, is the only exception with
430 THE SOLIDS.
which we are at present acquainted, of an organ which, being
furnished with an excretory duct, is yet not formed on the follicular
plan of development.
In all follicular glands, the secreting cells are situated on the inter-
nal surface of the basement membrane: in the liver, however, they
are placed upon its external surface, the true basement membrane
terminating with the termination of the biliary vessels.
Mr. Bowman regards the innumerable series of secreting cells as
representing the continuation of the biliary ducts, and a rudimentary
condition of which he considers them to be; in the same manner as
linear series of granular cells represent, according to some observers,
the rudimentary form of other vessels and tissues; as, for example, the
muscular fibre and the primitive nerve tubule.
Vascular Apparatus.
The vascular apparatus of the liver has been well understood since
the period of the publication of Mr. Kiernan's Researches. This
apparatus consists of hepatic veins, portal vein, and hepatic artery.
Hepatic Veins. — The venae cavae hepaticae commence in the centre
of each lobule of the liver by a plexus of capillaries, which penetrates
it in all directions; these uniting, form larger vessels, and which, again,
join together, to constitute the central lobular vein : this, escaping
from the lobule altogether, becomes what has been termed the sub-
lobular vein, and it next unites with other sub-lobular veins to form
the main branches of the hepatic veins. (Plate LV. fig. 1, 2.)
Portal Veins. — The portal vein is mainly formed by the union of
the inferior and superior mesenteric veins; and these, again, have
their origin principally in the confluence of the capillary vessels of
the villi of the small intestines.
The portal vein enters the substance of the liver at the transverse
fissure. After numerous ramifications, many of its branches are
spread over the outer surface of the lobules : these branches are called
the inter-lobular veins: from these branches others still smaller pro-
ceed; these, penetrating the substance of the lobules, break up into
capillaries, which unite with the capillaries of the lobular hepatic veins,
already spoken of; and it is the capillaries of both hepatic and portal
veins, thus united, that constitute the lobular capillary plexus. (Plate
IN. fig. 4; Plate L VI. fig. 1.)
The lobular plexus may be completely injected either from the
portal or hepatic veins, as might be supposed from the fact of its being
GLANDS
431
constituted of vessels derived from both. This plexus, however, is not
always fully injected : it is only when the operation of injection has
been very successfully performed that this result is secured : some-
times, in injecting from the portal vein, the injection fills only those
vessels which ramify on the surface of the lobules, viz : the interlob-
ular veins, as represented in Plate IN. fig. 4; in other instances, the
injection will penetrate further, and fill that portion of the lobular
plexus which is formed by the capillaries which belong especially to
the portal vein; in this case a zone of capillaries surrounds each lob-
ule, as figured in Plate LVI. fig. 1. In others, again, the injection
will fill the entire lobular plexus, and extend even to the central lob-
ular hepatic vein (Plate LVI. fig. 4); in this latter case, the entire
section of the liver appears but a mass of capillaries, the size and form
of the lobules being indicated merely by the cut extremities of the
larger lobular and inter-lobular vessels.
On the other hand, in injecting from the hepatic veins, the injection
may reach only the central lobular vein and its principal ramifications,
as shown in Plate IN. fig. 1 ; or it may fill that portion of the lobular
plexus especially formed by the capillaries of the hepatic veins, in
which case each lobule will appear to be the centre of a separate
injection (Plate IN. fig. 2); lastly, the entire lobular capillary plexus
is sometimes injected from the hepatic veins in the same manner as
from the portal vein.
In those instances in which two lobules are seen to be united
together, the vessels are also observed to proceed directly from one
to the other; this communication is especially evident in injections
of the hepatic veins. (Plate IN. fig. 2.)
The form of the portal vein, from its origin in the villi of the intes-
tines to its termination in the lobules of the liver, may then be com-
pared either to two trees joined by their trunks, or to a single uprooted
tree. The preceding account renders it evident that it is from the
blood contained in the portal vein that the secretion of bile takes place.
In those cases in which the blood-vessels become injected from the
biliary ducts, it is usually the portal system which receives the greater
part of the injection; and this is thrown into it at different points
irregularly, so that there are no definite zones of capillaries marking
out the lobules ; but masses of capillaries are seen here and there
arranged without any certain order.
Hepatic Artery. — The hepatic artery is the nutritious vessel of the
liver ; it supplies the vessels of the hepatic ducts, the vasa vasorum,
and the capsule of the liver.
432 THE SOLIDS.
It is distributed principally, however, to the capsules covering the
lobules, and to the general capsular investment of the liver.
Some of the inter-lobular or lesser capsular branches penetrate the
substance of the lobules, and terminate in the portal capillaries of
the lobular plexus. (See Plate LVI. fig. 2.)
The outer capsular branches are remarkable for their great length,
and the simple manner in which they divide and sub-divide.
The hepatic artery does not anastomose with the hepatic vein.
Pathology.
The pathology of the liver may be divided into two sections,
according as the seat of the disease affects its secreting or vascular
apparatus.
Secreting Apparatus.
Two abnormal conditions of the secreting cells of the liver have
been noticed : in the first, biliary engorgement, the cells are seen to
contain a greater quantity of biliary matter, in the form of globules
of various sizes, than ordinary; in the second, fatty degeneration of
the liver, the cells are laden with innumerable globules of an ole-
aginous character; this condition of the cells, of course, impairs, to
a very great extent, their secretory powers. (See Plate hVll.fig. 2.)
Livers thus laden with oleaginous particles have been termed fatty ;
this term, although expressive, is certainly incorrect. Fat is a dis-
tinctly organized cellular constituent of the higher forms of animal
organization ; and each true fat globule is a perfect cell, constituted
of nucleus and cell wall. The minute globules of oil existing in the
cells of the liver and of some other glands, especially in disease, have
none of the attributes of cells; they are merely globular collections
of an oily fluid, similar to those which exist in the cells of cartilages.
It is, therefore, evident that the term fatty, applied to organs
affected in the manner described, is scientifically and fundamentally
improper: the appellation of oily would be more correct.
The truly fatty liver and kidney do, certainly, occasionally present
themselves to our notice; in these, there is an accumulation of true
fat cells, not, indeed, within the epithelial particles, but in the inter-
spaces between the lobules and tubules, and also beneath the capsules
to a less degree.
The microscopic characters of the disease called cirrhosis do not
appear to have been as yet satisfactorily determined.
GLANDS. 433
Vascular Apparatus.
A knowledge of the distribution of the blood-vessels in the lobules
of the liver, has enabled the pathologist to explain satisfactorily-
various abnormal appearances connected with its vascular apparatus.
The lobules of the liver of persons or animals that have bled to
death, or that have died in an exceedingly anaemic condition resulting
from disease, present a pale and ex-sanguine appearance, arising from
the small quantity of blood contained within the blood-vessels.
A second very common appearance of the lobules of the liver,
after death, is that in which they are red in the centre, and pale
around the margin. This condition arises from the presence, in the
venous hepatic vessels, of a considerable quantity of blood, the portal
vessels being at the same time almost destitute of this fluid; it has
been called by Mr. Kiernan the first stage of hepatic venous conges-
tion, and is said to be due to the continuance of capillary action in
the vessels after the general circulation has ceased.
In the second stage of hepatic venous congestion, not merely the
centres of the lobules are red, but also the portal plexus in parts; the
parts of the lobules which are most free from congestion are those
surrounding the inter-lobular spaces; so that the non-congested por-
tions appear in the form of isolated and irregular patches, in the midst
of which are situated the inter-lobular fissures and spaces. The
second stage of hepatic venous congestion commonly attends disease
of the heai't and other disorders in which there is an impediment to
the venous circulation, and it also gives rise, in combination with
accumulation of bile in the secreting cells, to those various appear-
ances which characterize the nutmeg or dram-drinker's liver.
A third form of venous congestion is that which affects the portal
veins alone; in this the margins of the lobules are red, while their
centres are pale; it is the very reverse condition to hepatic venous con-
gestion in its first stage, and has been distinguished by Mr. Kiernan
by the name of portal venous congestion. This form of congestion
is rare, and has hitherto been noticed to occur in children only.
The fluid of the liver, the bile, has already been described in this
work; in addition to the epithelial scales derived from the mucous
membrane lining the gall-bladder, the bile frequently contains, when
inspissated, concrete masses of biliary matter, which have been mis-
taken for true cells ; also, crystals of cholesterine, gall-stones, and the
parasite called the fluke with its ova.
28
434 THE SOLIDS.
Hydatids are frequently developed in the substance of the liver;
these often attain a very large size.*
Development of the Liver.
"With respect to the development of the liver, the authorf considers the opinion
of Reichart to he decidedly the correct one, namely, that its formation commences
by a cellular growth from the germinal membrane, independently of any protrusion
of the intestinal canal. On the morning of the fifth day, the oesophagus and stomach
are clearly discernible, the liver lying between the heart, which is in the front, and
the stomach, which is behind ; it is manifestly a parenchymal mass, and its border is
quite distinct and separate from the digestive canal at this period ; the vitelline duct
is wide, it does not open into the abdominal cavity, but its canal is continued into an
anterior and posterior division, which are tubes of homogeneous membrane, filled,
like the duct, with opaque oily contents ; the anterior one runs forwards, and forms
behind the liver a terminal expanded cavity, from which then passes one offset, which
gradually dilating opens into the stomach; a second, which runs in a direction
upwards and backwards, and forms apparently a caecal prolongation; and a third and
fourth, which are of smaller size, arise from the anterior part of the cavity and run
to the liver, though they cannot be seen to ramify in its substance;" at a somewhat
later period, these offsets waste away, excepting the one which is continued into the
stomach, and then the mass of the liver is completely free and unconnected with
any part of the intestine. As the vitelline duct contracts, the anterior and posterior
prolongations of it become fairly continuous, and form a loop of intestine, the
posterior division being evidently destined to form the cloaca and lower part of the
canal. The final development of the hepatic duct takes place about the ninth day,
by a growth proceeding from the liver itself, and consisting of exactly similar mate-
rial ; this growth extends towards the lower part of the loop of the duodenum,
which is now distinct, and appears to blend with the coats of the intestine; around
it, at its lower part, the structure of the pancreas is seen to be in process of forma-
tion. The further process of development of the hepatic duct will, the author thinks,
require to be carefully examined; but the details he has given in this paper have
satisfied him of the correctness of the statement that the structure of the liver is
essentially parenchymal."
* On one occasion I noticed the liver to be thickly studded throughout with
numerous cysts, the largest of about the twelfth or eighth of an inch in diameter.
These cysts contained a gaseous fluid only ; the secreting cells included a greater
quantity of oil than natural.
f Dr. Handfield Jones, Abstract of Paper in Philosophical Magazine, September,
1847.
GLANDS. 435
LITER,
[For a very accurate account of the minute structure of the liver, with
excellent drawings, the reader is referred to a paper "on the Comparative
Structure of the Liver," by Dr. Jos. Leidy, of Philadelphia, and published in
vol. xv. (new series) of American Journal of Medical Sciences, pp. 13-23.
Dr. Leidy's researches are confirmatory of the views of Dr. Kiernan, as
laid down in the paper referred to in the text.
Appended to Dr. Leidy's paper, will be found a table containing the
measurements of the secretory cells of the liver in several of the different
orders of animals.
The minute structure of the liver should be studied in both the recent
state, and after injection ; the method in the recent state is the same as
already pointed out for other organs — thin sections in different directions,
dissected with needles under water, and viewed with low powers ; others
may be compressed, and treated with acetic acid, whereby the nuclei of
the secretory cells are readily brought into view.
The arrangement of vessels is of course best seen after injection. Any
one particular order of vessels may be filled, or the four orders may be
injected with different colours. When this is desired, the following division
will be the best : Arteries, blue ; vena portse, yellow ; hepatic vein, red ;
hepatic duct, white.
D'*s. Goddard and Neill have made some successful injections of the liver,
by which the four sets of vessels were filled ; using red for the arteries and
blue for the hepatic vein. It will be found more difficult to inject com-
pletely the liver than any other organ. After injection, sufficient time must
be allowed for drying. Slices may then be cut in different directions, and
after these have been moistened with turpentine, may be examined with a
low power. If the vessels seem to be well filled and distinct, without
extravasation, the specimens may be permanently mounted in cells with
Canada balsam, without heat.]
-136 THE SOLIDS.
PROSTATE GLAND.
This gland belongs to the compound follicular division, and not to
the lobular class of glands; its structure consisting of clusters of
follicles, united by ducts : these follicles are usually of an oval form,
of large size, and frequently communicate with each other.
The follicles cannot be exhibited separately as such, being mere
excavations or cells which exist in the substance of the gland, and
which are lined by prolongations of the mucous membrane of the
urethra.
That the follicles constituting the essential structure of the prostate
gland are simply inversions of the genito-urinary membrane, is proved
by the fact that the epithelium which lines them is of the clavate form,
which has been elsewhere described as appertaining to the bladder.
In consequence of the large size of the follicles, and of the fact of
the epithelium which lines them forming on their interior but a single
and even layer of cells, a considerable space or cavity exists in the
centre of each follicle.
The tissue out of which the follicles are formed, and to the presence
of which the prostate owes much of its size and nearly all its firmness,
is a good example of the nucleated variety of fibro-elastic tissue,
approaching in its characters very closely to the muscular fibre of
organic life.
The increase which so generally takes place in the size of the
prostate in old age is due to an increased development of the above-
named tissue.
From the preceding description, it would appear that the office of
the prostate is simply to secrete mucus, and that it does not, as has
been conjectured, furnish any peculiar secretion necessary, as some
even have supposed, to fecundity.
The most curious circumstance about the prostate is the almost
constant occurrence, in considerable numbers, of concretions or calculi
formed of concentric lamellae. These calculi are situated in the fol-
licles already described; they differ from each other very greatly in
size, form, and colour, and in the number, arrangement, and strength
of the concentric capsules. Ordinarily, the concentric lamellae are
disposed around a single nucleus of granular and amorphous matter;
sometimes, however, there are two or even three separate nuclei
within each calculus; in these cases, each nucleus will be encircled
by its own lamellae, the entire of them being also included in a greater
GLANDS. 437
or less number of larger lamellae. The form of the calculi, although
various, has a tendeney to the triangular; and the colour, although
differing in different glands, depends upon their size and age, the
younger and smaller being transparent and almost free from colour,
the older and larger being of a deep orange or ochre tint. (Plate
LYILjfe. 3.)
The prostatic calculi have been noticed by several observers ; by
Cruveilhier, Dr. Jones, Mr. Quekett, Mr. Adams, of the London Hos-
pital, Dr. Letheby, and myself.
Dr. Jones* describes them as originating in oval or rounded
nucleated and organic vesicles, which enlarge, and then have their
amorphous contents arranged into concentric laminae. Dr. Letheby
believes that "they are concretions which arise exactly like those of
the kidney and bladder, viz: by a succession of external deposits;"
this view is most probably the correct one.
Dr. Letheby has favoured me with the following observations on
the chemistry of these bodies: "You will find," he says,f "that they
consist of phosphate of lime, which is mixed up with a large quantity
of nucleated fat cells and inspissated mucus; the whole being gen-
erally tinted with some shade of yellow or red."
"They are slowly soluble in strong acetic and muriatic acids;
more quickly when heated, and they then leave numerous fat globules
and remnants of cells. They are not dissolved by potash or strong
ammonia. Heated before the blow-pipe, they char, and leave a small
residue of earthy matter."
The smaller calculi resemble closely the concentric corpuscles or
bodies described by Mr. Gulliver as occurring in. fibrinous clots, and
many of them do not present concentric lamellae.
TUBULAR GLANDS.
SUDORIFEROUS GLANDS.
The sudoriferous are the most numerous class of glands in the body,
their apertures thickly studding the entire external surface, and far
outnumbering the sebaceous glands, which have a somewhat similar
distribution.
They consist of convoluted tubes of nearly equal diameter, which
unite, at irregular intervals, with each other, forming looped meshes, all
of which terminate in a single excretory duct. (See Plate LVII.j^g-. 4.)
* Medical Gazette, 1847. f In litt.
438 THE SOLIDS.'
The excretory duct is either straight or coiled spirally, and it
Always terminates in a raised and rounded mammillary process, evi-
dent on the surface of the epidermis. (See Plate XXIII. fig. 1.) It
is straight where the epidermis which it has to pass through is thin,
and where, in consequence, its course to the surface is short; on the
other hand, it is coiled in spires which are remarkable for their
extreme regularity, where this membrane is thick, as in the palms of
the hands and soles of the feet (see Plate XXIV. fig. 3), and where
as a result its course is prolonged. The acting cause which deter-
mines this spiral arrangement is probably the gradual flattening to
which the outer and older layers of epidermic cells are continually
subject from pressure.
The duct of the sudoriferous glands is formed by an inversion of
the epidermis itself, similar to that which forms the lining of the hair
follicles. The sudoriferous glands never open into the hair follicles,
but in the intervals between them, and also between the sensory
papillae with which the true skin is covered.
The palms of the hands and soles of the feet, being entirely free
from the sebaceous glands, are occupied exclusively with the sudorif-
erous; they are placed in lines or rows, which are variously curved,
and which correspond with the arrangement of the sensory papillae of
the true skin. The apertures of the sudoriferous glands on the ridges
of the skin are just perceptible with the naked eye, but they become
verv evident and conspicuous with a lens of moderate power. (Plate
XXIV. fig. 1.)
The secreting cells of the sudoriferous glands are small.
The tubes are formed like those of the testes of a nucleated variety
of fibro-elastic tissue, and are surrounded by a similar plexus of capil-
laries. These vessels, as well as the tubes themselves, are held in
position by bands of fibrous tissue.
The following calculations by Mr. Wilson will serve to convey some
idea of the extent and importance of the sudoriferous system :
" To arrive at something like an estimate of the value of the perspiratory system in
relation to the rest of the organism, I counted the perspiratory pores on the palm of
the hand, and found 3,528 in a square inch. Now, each of these pores "being the
aperture of a little tube of about a quarter of an inch long, it follows that, in a square
inch of skin on the palm of the hand, there exists a length of tube equal to 882 inches,
or 73 5 feet. On the pulps of the fingers, where the ridges of the sensitive layer of
the true skin are somewhat finer than in the palm of the hand, the number of pores
on a square inch a little exceed that of the palm; and on the heel, where the ridges
are coarser, the number of pores on the square inch is 2,268, and the length of tube
GLANDS. 439
667 inches, or 47 feet. To obtain an estimate of the length of tube of the perspira-
tory system of the whole surface of the body, I think that 2,800 might be taken as a
fair average of the number of pores in the square inch ; and 700, consequently, of the
number of inches in length. Now, the number of square inches of surface in a man
of ordinary height and bulk is 2,500 ; the number of pores, therefore, 7,000,000 ;
and the number of inches of perspiratory tube, 1,750,000; that is 146,833 feet, or
48,600 yards, or nearly twenty-eight miles." *
See Appendix, 547 ?
SUDORIPAROUS GLANDS.
[The paper by Mr. Rainey, referred to in the Appendix, undoubtedly
gives the true structure of the sudoriparous glands, and their ducts: hence
most of the figures given in the standard works of Physiology, of the course
and structure of these ducts, will be found incorrect. The course of these
ducts is perhaps not stated at sufficient length in the Appendix. Mr. Rainey
divides the duct into two portions, that passing through the dermis, or dermic
portion, and that continuous through the epidermis, or epidermic portion.
"The membrane composing this duct is thin and transparent, and of considerable
strength; and becomes gradually dilated at its upper part, and terminates by becom-
ing contiguous with the basement membrane, covering the adjacent papillae, and is
not continued through the cuticle to the surface.
" The duct is lined with epithelium, which appears to have no regular form below,
being merely finely granular, but which becomes more distinct at its upper part,
where it is continuous with the deep layer of the epidermis; namely, that lying
upon the basement membrane.
" These lowest cells possess a greater degree of coherence than those which are
situated above them ; so that when the epidermis is separated from the cutis after
maceration, they come away with the cuticle in a tubular form, being in fact the
lining of the duct, leaving the basement membrane of the papillae and the mem-
branous part of the duet in the areolar tissue. That part of the duct which traverses
the epidermis, and which may be called, for distinction, the epidermic portion, is
altogether of a different structure to the one just described, not having like it mem-
branous parietes, but merely being a spiral passage between epidermic cells and scales.
" In the scaly or superficial layer of the cuticle, the passage is made up entirely of
epidermic scales, placed with their flat sides parellel with the axis of the tube which
they compose: while in the corpuscular or deep layer of the epidermis, the passage
is situated between scales above and cells below, which cells being less and less
* Diseases of the Skin, p. 18.
440 THE SOLIDS.
perfect, as they are situated nearer the basement membrane, render the parietes of
the duct at its origin between the papillse very indistinct; this part of the duct being
merely a passage through a confused stratum of cell-nuclei and blastema, and
gradually contracting in diameter as it approaches the dermic portion, insensibly
disappears : hence its inferior extremity cannot be clearly defined by the microscope/'
The sudoriparous glands and their ducts are best studied in thin sections
of the skin from the palm of the hand or the sole of the foot. Fresh
integument will be found best for making these sections, although it will
require many attempts before sections can be obtained which will show the
gland and its duct in its whole course to its external opening.
Sometimes thin sections can be best obtained after the skin has been
hardened in sulphuric ether, or in a solution of chromic acid, or potash.
A good Valentin's knife, or a broad thin razor, is the best instrument for
making these sections. When a satisfactory specimen is obtained, it should
be mounted in a shallow cell with fluid ; the best for this purpose are
Goadby's B-fluid, naphtha and water, or a very weak solution of chromic acid.
Plate LXXVIL, fig. 1, exhibits the sudoriparous glands and the course of
their ducts.
" " fig. 2, A more highly magnified view.]
GLANDS. 441
AXILLARY GLANDS.
These glands, first described by Professor Horner and M. Robin,
are probably but a variety of the ordinary sudoriferous glands.
They are situated in the axillae, are similar in organization to the
sudoriferous glands, but are much larger than these.
They doubtless furnish the peculiar and odorous secretion, which
characterizes the region of the axillae.
This odorous principle, it is said, exists in the blood ready formed,
and the glandulae merely separate it from that fluid. It is also stated
that its presence may be detected, in dried blood, on the addition of
sulphuric acid, and that its odour is different in the male and female;
also, that even the blood of different animals may be distinguished by
means of it; assertions which are very doubtful.*
CERUMINOUS GLANDS.
The ceruminous glands are situated beneath the integument of the
deeper part of the external meatus of the ear. They occur mixed up
with numerous sebaceous glands, but have no direct communication
with these, as they open on the surface by distinct apertures.
They resemble very closely in structure the sudoriferous glands
just described, consisting, like them, of convoluted and looped tubes,
which unite together and end in a slender duct. They differ, how-
ever, from the sudoriferous glands in the fragile character of the tubes,
which renders it somewhat difficult to procure a perfect preparation
of one of them; this difference seems to arise principally from the
absence, in a great measure, of fibrous tissue, whereby, in the sudor-
iferous glands, the tubes are bound together, as well as of also
enveloping plexuses of blood-vessels. (See Plate hVU.Jig. 5.)
In the external ear of the sheep, in which these glands mav be
studied to great advantage, the tubes appear of a pale straw-colour,
transparent and glossy, with but few apparent granular cells, and
these totally different from the characteristic cells of the sebaceous
glands, filled with innumerable globules of oil. The granular cells
rilling the tubes, and which are usually concealed by a quantity of oily
fluid, may be made apparent by the addition of acetic acid. The mem-
brane of the tubes is composed of a nucleated form of elastic tissue.f
* Annales d'Hygnne, vol. i. ii. x. &c.
f It seems doubtful, after all, whether the ceruminous are any thing more than a
variety of the sudoriferous glands.
442 THE SOLIDS.
From the fact of the ceruminous glands coexisting with numerous
sebaceous glands, it seems probable that the cerumen is the mixed
production of the two descriptions of glands.
The substance of the kidney, like that of the other large glands, may
be divided, for the purposes of description, into two orders or systems
of structure or apparatus: the glandular or secretory, which is the
most important and characteristic; and the vascular, which is but
subordinate.
Secreting Apparatus.
The secreting apparatus of the kidney consists of the tubes; their
enlarged and globular extremities, which, in part, constitute those
peculiar and interesting structures, the Malpighian bodies, and their
contained granular cells. (See Plate LVIII. figs. 1. 6; Plate LX.
figs. 2, 3.)
Tubes. — The substance of the kidney is divided into an outer
cortical and an inner or medullary part. The former is generally
conceived to be the secreting portion of the kidney, and the latter
merely the tubular or conducting portion through which the urine
passes in its way to the ureter. This notion of the nature of the two
parts and of their mutual relation is certainly erroneous, as is proved
by the facts that both portions of the kidney are alike formed of tubes,
and that all these tubes are abundantly furnished with secreting cells.
The secreting structure of the cortical part of the kidney is distin-
guished by the large size of its tubes; their tortuous course; the loops
formed by them, not merely on the surface of the kidney, but also in
its interior; by the globular enlargements in which they terminate;
and by the larger size, &c, of their contained cells.
The medullary part of the kidney is characterized by the smaller
calibre of its tubes, their straight course, the absence of dilated extrem-
ities, and the frequency of the union of the tubes with each other.
The tubes, then, of the kidney, describing their course from without
inwards, commence in dilated extremities (see Plate LX.figs. 2, 3),
which form part of the structure of the Malpighian bodies; they after-
wards take a tortuous course, describing loops on the surface of the
organ, as well as in its interior (see Plate LIX. fig. 2, and Plate
LVIII. fig. 1), until they reach the medullary part, when their course
becomes straight, and where they frequently unite, especially near its
lower portion, in a dichotomous manner, thus forming a number of
GLANDS. 443
larger tubes, which terminate in the mammillary processes which dip
into the midst of the chambers called calices.
According to the above description of the course and origin of the
tubes of the kidney, which is now the generally received one, each
tube commences in a single dilated extremity; it seems to me, how-
ever, to be probable that many of the tubes have their origin in loops;
the fact of the occurrence of loops throughout both the medullary and
the cortical parts of the kidney, the universal formation of loops on
the surface of that organ, and the non-existence of dilated extremities
of tubes on that surface, all tend to prove the correctness of the view
just mentioned.
The tubes of the kidney, wherever encountered, consist of a strong
and structureless basement membrane (see Plate LVIII. fig. 1); it is
worthy, however, of especial notice that these tubes, as well as their
globular terminations, are all enclosed in a frame-work constituted of
a nucleated form of elastic tissue. This frame- work is seen to most
advantage in cross-sections; this it is which keeps the tubes distinct
from each other, and which explains the occurrence of intervals
between the tubes, seen especially in longitudinal sections. (See
Plate LVIII. fig. 2.)
Malpighian Dilatations. — It is certain that some, if not all, of the
tubes terminate in enlarged extremities. These dilatations constitute
the Malpighian bodies in part only; they are of a globular form, and
their diameter exceeds five or six times that of the tube itself. (See
Plate LX. Jigs. 2, 3.) They vary, however, considerably in size, in
all parts of the cortical substance of the kidney; and Mr. Bowman
states that they are largest near to the point of junction between the
cortical and medullary portions.
The best way to obtain a satisfactory view of these bodies is to tear
up with needles a fragment of the cortical substance of the kidney,
and to search among the divided shreds for the Malpighian dilatations,
which are there met with in all possible conditions. Some will be
seen entirely detached, lying loose in the water in which the fragment
has been torn up, others will be observed to be attached to the tubes
which take their origin from them. All of these, however, whether
attached or loose, will occur in one of two states; either the surface^
of each will be seen to be constituted of convoluted and branched tubes,
the vessels of the Malpighian plexus ; or it will appear perfectly smooth
and even. The former condition is the more frequent; the latter is
by far the less common, and is explained by the fact that in this case
444 THE SOLIDS.
the Malpighian dilatation is enclosed in a capsule of fibro-elastic tissue
of considerable thickness, a continuation of that which invests the
tubes themselves. (See Plate LX.Jigs. 2, 3, and Plate LVIII.^. 2.)
The Malpighian dilatations rarely, if ever, extend to the surface of
the kidney; they have been, in all the instances in which they have
been noticed by the author, covered by convolutions of the tubes.
Epithelium. — The epithelium of the kidney presents several well-
marked modifications, in different localities of that organ.
The epithelium of the tubes of the cortical part of the kidney, save
within a short distance of their junction with the Malpighian dilata-
tions, is composed of large and angular scales or cells, which are
coarsely granular, and which form a regular layer of pavement epithe-
lium lining the tubes; the centres of these are unoccupied with cells,
and are thus left pervious for the passage of the urine. (See Plate
LVIII. Jig. 6.)
The cells forming the epithelium of the tubes of the medullary part
of the kidney are of much smaller size than those contained in the
tubes of its cortical substance, consisting of nuclei, surrounded by a
very narrow border. (See Plate LVIII. Jig. 6.)
The cells situated at the neck of the Malpighian dilatations are of
the ciliated kind: these were first noticed by Mr. Bowman in the
kidney of the frog, and that gentleman conjectured their existence in
the higher animals; the author has seen them in action in the sheep,
rabbit, and horse. (See Plate LX. Jig. 3.)
Lastly, the cells which invariably line the Malpighian dilatations of
the tubes are small, and furnished with oval nuclei. (See Plate LX.
Jig. 3.) Mr. Bowman considered that epithelium was not constantly
present in these bodies; and that, when it was so, it only lined that
portion of them in connexion with the tubes. This statement arose
in a misapprehension of the real structure of the Malpighian body.
Vascular Apparatus.
The vessels of the kidney consist of the renal artery and vein; also,
of a vein which may be called portal : we will first trace the course
of the artery.
Renal Artery. — The renal artery, after its entrance into the sub-
stance of the kidney, divides into numerous branches, some of them
pass between the medullary cones, others traverse these in sets:
arrived at the cortical part of the kidney, many undergo a further
sub-division, and some, passing towards the Malpighian dilatations,
GLANDS. 415
form in part, upon its external surface, the Malpighian tuft or plexus
of vessels (see Plate LIX. Jigs. 1.5); others continue onwards to the
surface of the kidney, and there terminate in capillaries. (See Plate
LIX. _/£§-. 2.) Such is a brief sketch of the course of the renal artery.
The branches of the renal artery take, through the cortical part of
the kidney, a straight and parallel course; some of these branches
give off lesser vessels on each side, which pass towards, and are
expended upon the Malpighian dilatations, as also are, ultimately, the
terminations of the main vessels from which the lesser ones proceeded.
Others, again, of the larger and parallel branches, in like manner give
off Malpighian twigs; but their terminations, in place ■ of being
exhausted upon the Malpighian dilatations, reach the surface, and
there form, with the branches of the renal vein, an inter-lobular
plexus. It is seldom that a branch of the artery reaches the surface
of the kidney, without first communicating with the Malpighian
dilatations.
Renal Vein. — The renal vein has two origins : one in the capilla-
ries on the surface of the kidney ; these capillaries, uniting with those
of the renal artery, form the plexus, which ramifies in the interstices
left between the terminal loops of the tubes (see Plate LIX. jig. 2) ;
the second origin is in the plexus of capillaries surrounding the tubes
formed by the junction of the capillaries of both artery and vein;
from these two origins and plexuses branches proceed ; these, uniting
with each other, form larger vessels, which also pass through the
medullary part of the kidney in sets. (See Plate LVIII.j%s. 4, 5.)
Portal Vein. — Each Malpighian tuft or plexus of vessels is formed,
like other plexuses, of capillaries derived in part from an artery and
in part from a vein. As a single arterial twig proceeds to each
Malpighian dilatation — the afferent vessel, so a single venous twig
departs from it — the efferent vessel ; this vessel is usually of much
smaller size than the artery, and terminates in the capillaries which
encircle the uriniferous tubes. (See Plate LX. jig. 2.)
The efferent vessel of the Malpighian tuft resembles in its origin
and distribution the portal vessel of the liver, being in connexion
with capillaries, at both its origin and its termination: in consequence
of this resemblance, it has been termed by Mr. Bowman the portal
vein of the kidney; and as each Malpighian plexus has a separate
efferent vessel, to the aggregate of these that gentleman applies the
term "portal system" of the kidney.
The above description of the vascular distribution belonging to the
446
THE SOLIDS.
kidney differs, in some important respects, from that given by Mr.
Bowman, as we shall now proceed to make apparent.
In the first place, Mr. Bowman describes the afferent vessel of the
Malpighian tuft as piercing the membrane of the enlarged extremity
of the tube, and as forming within this, by its numerous sub-divisions,
the Malpighian plexus : the efferent vessel, in like manner, perforating
the membrane of the dilatation, or proper capsule.
This view of the position of the Malpighian plexus is undoubtedly
incorrect; this plexus, like every other plexus belonging to glands
formed on the tubular or follicular types, is situated on the external
surface of the basement membrane, that is, embracing the globular
head of the tubes, and lying between this and the frame-work of elastic
tissue already described. Analogy, therefore, is entirely opposed to
the description of the author of the paper in the Philosophical Trans-
actions to which reference has been made more than once.
In the second place, Mr. Bowman describes the renal artery as
being spent upon the Malpighian bodies, with the exception of a few
branches given off to the coats of the excretory ducts and of the
larger vessels ; while, according to the author's observations, only a
proportion of the branches of the renal artery are thus disposed of.
The accuracy of the foregoing account of the distribution of the
blood-vessels of the kidney is borne out, to a very great extent, by
the results furnished by injection.
1st, The Malpighian plexus can be injected with great facility by
the artery, but not by the vein: the reason of this will be obvious on
a little reflection; the branches of the renal artery pass directly to
the Malpighian plexus; those of the renal vein, commencing from the
larger or terminal trunks, end either in the plexus surrounding the
tubes of the kidney, or in that which lies on its surface between the
convolutions of those tubes; and it is in one or other plexus that the
efferent or portal vein of the Malpighian tuft terminates; so that
between the terminal branches of the renal vein and the origin of
the efferent vessel, a complicated plexus is interposed — that surround-
ing the uriniferous tubes; the injection, therefore, before reaching the
Malpighian tuft, would have to traverse the plexus already spoken of;
and it is this which accounts for its being so difficult, if not impossible,
to inject the Malpighian plexus from the renal vein.
2d. The plexus surrounding the tubes may be injected with care,
from both the artery and vein ; but especially from the latter.
3d. The plexus, ramifying between the loops of the tubes on the
GLANDS. 447
surface of the kidney, may also be readily injected from either artery
or vein.
Occasionally, the injection will pass from the blood-vessels, and
escape into the tubes, or their Malpighian extremities.
The tubes themselves, and very rarely their globular terminations,
may be injected from the ureter: this is accomplished more readily
in the kidneys of some animals, as the horse, than in those of man.
A complete Malpighian body, then, consists of the globular enlarge-
ment of the tube, over which is spread the Malpighian plexus, formed
by branches of the renal artery and portal vein; this plexus does not
consist entirely of capillary meshes, but of vessels of different diame-
ters; the artery divides and sub-divides: its terminal branches are,
however, capillary in size, but, in place of forming distinct meshes,
follow a serpentine and convoluted course. (See Plate LX. fig. 2.)
Mr. Bowman conceived, as already noticed, that the Malpighian
plexus was situated within the globular enlargement of the uriniferous
tube; and, reflecting on the remarkable structure of the Malpighian
bodies, and on their singular connexion with the tubes, was led to
consider that the tubes and their plexus of capillaries are the parts
concerned in the secretion of that portion of the urine to which its
characteristic properties are due (the urea, lithic acid, &c), while
the Malpighian bodies are an apparatus destined to separate from the
blood the watery portion of the urine.
"It would indeed "be difficult," Mr. Bowman writes, "to conceive a disposition of
parts more calculated to favour the escape of water from the blood than that of the
Malpighian body. A large artery breaks up, in a very direct manner, into a number
of minute branches, each of which suddenly opens into an assemblage of vessels of
far greater aggregate capacity than itself, and from which there is but one narrow
exit. Hence must arise a very abrupt retardation of the velocity of the current of
blood. The vessels in which this delay occurs are uncovered by any structure.
They lie bare in a eell from which there is but one outlet, the orifice of the tube.
This orifice is encircled by cilia, in active motion, directing a current towards the tube.
These exquisite organs must not only serve to carry forward the fluid already in the
cell, and in which the vascular tuft is bathed, but must tend to remove pressure from
the free surface of the vessels, and so to encourage the escape of their more fluid
contents. Why is so wonderful an apparatus placed at the extremity of each urin-
iferous tube, if not to furnish water, to aid in the separation and solution of the
urinous products from the epithelium of the tube?" — P. 75.
My view of the nature of the Malpighian body differs, in some
respects, from that entertained by Mr. Bowman. The proper Mal-
pighian capsule is invariably lined by innumerable granular cells; for
448 THE SOLIDS.
this single and simple reason, therefore, I regard this body as a secret-
ing organ as much as the uriniferous tubes themselves, which present
an organization essentially the same. I differ, therefore, from Mr.
Bowman, who considers the epithelium of the tubes as the sole true
secreting agents of the urine. I conceive that this fluid is formed in
every part of the tubular and Malpighian surface of the kidney, and
I dissent from the opinion that the Malpighian body is an apparatus
destined for the simple separation of the watery parts of the urine
apart from any act of secretion.
Nevertheless, I so far agree with Mr. Bowman in his theory, as to
consider that the greater portion of the more watery parts of the
urine proceed from the Malpighian bodies ; not, however, by an act
of simple separation, but by one of secretion. The peculiar arrange-
ment of the blood-vessels, and the presence of ciliated epithelium at
the entrance to the tubes, are facts in themselves sufficiently conclu-
sive of the accuracy of this view : as, on the other hand, I conceive
the great extent of secreting surface presented by the tubes to be in
itself sufficient to prove that at least a portion of the aqueous constit-
uent of the urine emanates from this surface.
An accurate knowledge of the pathology of the kidney and urine
would, doubtless, furnish arguments conclusive as to the relative
functions and importance of the tubes, and their enveloping plexus
and the Malpighian bodies.
The reader will at once observe that one of the arguments in favour
of Mr. Bowman's theory, urged in the preceding exposition, does not
hold good, in consequence of its want of accordance with the true
structure. I allude to the supposed entrance of the plexus into the
cavity of the proper Malpighian capsule.
In birds and reptiles, the Malpighian plexus is not formed of a
number of convoluted vessels, resulting from the repeated sub-division
of the afferent artery, as is the case in all the Mammalia, but simply
consists of a single coiled vessel, so that the afferent and the efferent
vessels of each tuft are one and the same by direct continuity. In
these classes, the efferent vessel readily admits of being injected
from the artery, and this in consequence of the simplicity of the plexus
surrounding the Malpighian enlargement.
The size of the Malpighian bodies varies, not merely in the same
kidney, but also to a still greater extent in the kidneys of different ani-
mals : they are largest in the elephant and horse, and smallest in birds.
GLANDS. 449
Development of the Kidney.
According to Dr Carpenter, "The first appearance of any thing resembling a
urinary apparatus in the chick, is seen in the second half of the third day. The
form at the time presented by it is that of a long canal, extending on each side of
the spinal column, from the region of the heart towards the allantois; and the sides
of these present elevations and depressions, indicative of the commencing develop-
ment of caeca.
"On the fourth day, the Corpora Wolfflana, as they are termed, are distinctly
recognised, as composed of a series of csecal appendages, which are attached along
the whole course of the first-mentioned canal, opening into its outer side. On the
fifth day, these appendages are convoluted; and the body which they form acquires
increased breadth and thickness. They evidently then possess a secreting function;
and the fluid which they separate is poured by the long straight canal into the cloaca.
Between their component shut sacs numbers of small points appear, which consist of
little clusters of convoluted vessels exactly analogous to the Corpora Malpighiana
of the kidney. The Corpora Wolfliana, however, have only a temporary existence
in the higher Vertebrata, although it seems that in fishes they constitute the perma-
nent kidney. The development of the true kidneys commences in the chick about
the fifth day. They are seen, on the sixth, as lobulated grayish masses, which sprout
from the outer edges of the Wolffian bodies ; and they gradually increase, the tem-
porary organs diminishing in the same proportion. The sexual organs, as will be
hereafter explained, also originate in the Wolffian bodies; and at the end of foetal
life, the only vestige of the latter is to be found as a shrunk rudiment situated near
the testes of the male. The progress of development in the human embryo seems
closely conformable to the foregoing account. The Wolffian bodies begin to appear
towards the end of the first month; and it is in the course of the seventh week that
the true kidneys first present themselves. From the beginning of the third month,
the diminution in the size of the Wolffian bodies goes on pari passu with the increase
of the kidneys ; and at the time of birth, scarcely any traces of them can be found.
At the end of the third month, the kidneys consist of seven or eight lobules, the
future pyramids ; then- secreting ducts still terminate in the same canal, which receives
those of the Wolffian bodies and of the sexual organs. And this opens with the
rectum into a sort of cloaca, or sinus urogenitalis, analogous to that which is perma-
nent in the oviparous Vertebrata. The kidneys are at this time covered by the supra-
renal capsules, which are very large; about the sixth month, however, these have
decreased, while the kidneys have increased, so that their proportional weight is as 1
to 4£. At birth, the weight of the kidney is about three times that of the supra-
renal capsules, and they bear to the whole body the proportion of 1 to 80 ; in the
adult, however, they are no more then 1 to 240. The Corpora Wolfliana are, when
at their greatest development, the most vascular parts of the body next to the liver;
four or five branches from the aorta are distributed to each, and two veins are returned
from each to the vena cava. The upper veins and their corresponding arteries are
converted into the renal and emulgent vessels; and the lower, into the spermatic
vessels. The lobulated appearance of the kidney gradually disappears; partly in
consequence of the condensation of the areolar tissue, which connects the different
parts; and partly through the development of additional tubuli in the interstices."
29
450 THE SOLIDS.
It is only necessary to observe, in addition to the description of
Dr. Carpenter, that, although the development of the kidney com-
mences near to the Wolffian body, it is yet not formed out of it, but
has an independent origin in its own proper blastema or primordial
matter. In its earliest condition in the Mammalia, it consists of tubes
proceeding from the hilus outwards towards the circumference in
bundles ; these tubes afterwards separate and become contorted, yet
all terminate in enlarged and vesicular extremities — the Malpighian
bodies. In the earliest state in which the kidney can be examined,
the ceeca alone exist in connexion with short tubes; the central or
proximal extremities are free, and not yet united to the ureter. This
fact proves that the kidney is not an involution of the genito-urinary
mucous membrane, but an independent formation, as is, probably,
every other gland.
Such is a simple, concise, and, it is believed, in all essential partic-
ulars, a correct account of the normal anatomy of the kidney.
Reference to the various discrepant, contradictory, and often erro-
neous statements of many writers on this subject has been hitherto
purposely avoided, lest such should obscure the simplicity of the
description just given. A few of the more remarkable statements
and opinions advanced respecting the anatomy of the renal organs
may now, however, be noticed with advantage and interest.
Every statement, without exception, made by Mr. Bowman, one of
the earliest and very best writers on the minute anatomy of the kid-
ney, has been from time to time contradicted by different observers;
by others, again, the descriptions of that gentleman have been con-
firmed, and not denied. As might be readily imagined, the truth lies
not exclusively with either the denying or the confirming observers.
Thus, the reality of any connexion existing between the tube and
the Malpighian body has been questioned and denied, and still con-
tinues to be so ; as also the existence of a vibratile epithelium in the
upper portion of the uriniferous tube. The first particular has been
denied by Miiller,* Reichert,"f Gerlach and Bidder; and the second
has been doubted or denied by Huschke, Reichert, and Bidder. On
the other hand, the observations of Schumlansky,J and A. Kolliker
* "De Glandularum Secernentium Structura Peinitiori Earumque prima fonnatione
in Homine atque Animalibus, Commentatio Anatomica." — Cum Tabulis sen. incisis
xvii. Leipske, 1830.
f Berichl ilber die ForischriUe der Mikroscopischen Anatomie in dem Jahre, 1842;
von K. B. Reichert, Prof, in Dorpat, Miiller's Archiv. 1843.
\ "De Structura Renum," 8vo. 1788.
GLANDS. 451
of Zurich, accord with those of Mr. Bowman on the first particular,
and those of BischofF, Valentin, Pappenheim, Gerlach, and Kolliker,*
on the second, the latter observer describing the entire epithelium of
the tubes as ciliated.
It is so easy, however, to satisfy ourselves, in the kidney of every
animal, of the reality of a connexion between the tube and the Mal-
pighian body, as well as of the presence of a ciliated epithelium, in
the upper portion of the uriniferous tubes, that it would be perfectly
unjustifiable for observers again to call these two points in question.
The statement of Mr. Bowman which has met with most opposition,
is that made as to the entrance of the Malpighian capillary plexus into
the cavity of the true capsule. Some observers have denied the cor-
rectness of this description, on the simple ground of the anomalous
position in which the blood-vessels would be placed, were such an
arrangement the true one. This objection, however, is insufficient to
disprove the accuracy of Mr. Bowman's explanation, since in the liver
there is every reason to believe that the vascular and secreting ele-
ments of glands are intimately associated. Again, some observers,
not satisfied with Mr. Bowman's description, have given others.
Thus, Gerlachf says that the Malpighian capsule is not, as Mr.
Bowman described it, a blind termination of a uriniferous duct, but a
retraction or introversion, a diverticulum of the same structureless
membrane which forms the uriniferous tubes; also, "that when the
Malpighian capillary net-work is closely examined, after the capsule
has been entirely detached from it, we see it in its whole extent
covered by a thick layer of nucleated cells, which are continued from
the inner wall of the capsule upon the Malpighian vessels; and the
latter lie introverted within a layer of cells, like an intestine within
the peritoneum.";};
Gerlach's description is assuredly incorrect: the views of the
structure of the Malpighian body, entertained by Bidder, § although
they approach more nearly to the truth, are also inaccurate: he con-
siders that the glomerulus, or vascular plexus, is inserted or pushed
* Ueber Flimmerbewig-ungen in den Primordial Nleren, Archiv. fur Anatomie,
Physiologie, und Wissencliaflliche Medicin, Heft V. S. 518. 1845.
f Beitrdge zur Slructurlehre der Niere, von Dr. Joseph Gerlach, prakt in Mainz
(Mayenee), Miiller's Archiv. 1 845.
I Edinburgh Medical and Surgical Journal, October, 1847.
§ Ueber die Malpighischen Korper der Niere, von F. Bidder in Dorpat, Miiller's
Archiv. 1845.
452 THE SOLIDS.
into the expanded portion of the uriniferous canal ; this on its part
embracing and surrounding the glomerulus. According to this view,
the glomerulus would still be external to the cavity of the dilated
extremity of the tube, the relation between the two being comparable
to the head within the double night-cap.
The correct view of the structure of the Malpighian body is, how-
ever, much more simple than either of those just described. A
Malpighian body, as already stated, consists of the dilated extremity
of a uriniferous tube, over which is spread the Malpighian plexus:
these two structures viz: the dilatation of the uriniferous tube, and
the vascular plexus, constitute all that is essential in the anatomy of
the Malpighian body: both are enclosed in a thick capsule: this is
not, however, a structure peculiar to the Malpighian body, but a mere
envelope, similar to, as well as a continuation of, that which invests
the tubes themselves.
A little reflection will show that this view reconciles many of the
conflicting statements made in reference to the anatomy of the Mal-
pighian body. The outer capsule referred to, which is that spoken ot
by most other observers as the true Malpighian capsule, is evidently
that which Mr. Bowman had in view as the dilated extremity of the
uriniferious tube, and it is this which he described as being pierced by
the Malpighian artery — a description literally and positively correct.
The common envelope, which, however, as already stated, forms
no necessary part of the Malpighian body, is really pierced by both
the afferent and efferent vessels of that body, as well as by the tube.
(See Plate LX. fig. 3.) Mr. Bowman's error consists in having
regarded this mere outer covering as the true dilated extremity of the
uriniferous tube, which it most certainly is not, and in having neces-
sarily, as a consequence, overlooked the true extremity of the urin-
iferous tube with its contained epithelium.
Again, the confounding of this common envelope with the true Mal-
pighian capsule accounts for the assertions of those observers who
state that the uriniferous tube has no connexion with that capsule :
it has, indeed, no connexion by continuity; it simply pierces it: of
the inner or true capsule, the uriniferous tube is absolutely a
continuation.
The common envelope of the entire and perfect Malpighian body
differs structurally from the true capsule : the latter is thin and struct
ureless ; the former, thick, and constituted of a delicately fibrous and
nucleated form of elastic tissue.
GLANDS. 453
Mr. Toynbee* is the only writer, with whose observations I am
acquainted, who understands the true character of what is ordinarily
regarded as the "capsule of the Corpus Malpighianum:" this he cor-
rectly describes as being a distinct globular investment, and not, as
was supposed, an expansion of the tube.
Notwithstanding, however, the knowledge of this fact, Mr. Toyn-
bee's views of the structure of the Malpighian body appear to me to
be far from correct.
Thus, Mr. Toynbee describes the Malpighian body as "composed
of two distinct elements — a plexus of blood-vessels, and a membranous
capsule, which completely surrounds and envelopes the plexus."
Each Malpighian body is indeed composed of two distinct and
essential elements, the dilated extremity of the uriniferous tube
embraced and surrounded by the Malpighian plexus: the outer
investment, called by Mr. Toynbee and others " the capsule," is not a
structure essential to the Malpighian body, since it alike invests this
and the uriniferous tubes for its whole length attached to it.
Again, Mr. Toynbee describes the uriniferous tube, after pene-
trating the capsule, as twisting into a coil, and after being in contact
with the ramifications of the corpus, as emerging from the capsule.
This last statement shows that Mr. Toynbee was unacquainted
with the proper character of the most important and essential of the
two elements of the Corpus Malpighianum, viz : the dilated extremity
of the uriniferous tube, filled with its secreting cells.
Pathology.
The kidney would appear to be more liable to morbid alterations
than any other organ in the body; nevertheless, its pathology is still
far from being completely understood, notwithstanding that several
observers have paid especial attention to the subject. Several of the
pathological conditions of this organ appear to have been confounded
together under the common term "Bright's Disease."
A very frequent pathological condition of the secreting cells of the
kidney is that in which they are laden with globules of an oily fluid,
similar to those which occur in the hepatic cells in the affection com-
monly called fatty liver, or fatty degeneration of the liver, but which
would be more correctly distinguished by the appellation of oily liver;
* " On the Intimate Structure of the Human Kidney, and on the changes which its
several parts undergo in Bright's Disease." By Joseph Toynbee, F. R. S. — Medico-
Chirurgical Transactions, June 1846.
454 THE SOLIDS.
the corresponding affection in the renal organ being known by
the name of oily kidney.
It is this condition of the renal cells which, in Dr. George John-
son's* opinion, constitutes the true Morbus Brightii.
The large, smooth, and mottled kidneys are those in which the oily
matter abounds; the smoothness, according to Dr. Johnson, depend-
ing upon the uniform distribution of the tubes in the cortical portion of
the kidney with the oily matter.
The wasted and granular kidneys, according to the same observer,
are those in which the accumulation of fat takes place less rapidly
and less uniformly; certain of the convoluted tubes becoming dis-
tended with fat, forming prominent granulations ; and these, pressing
upon the surrounding' tubes and vessels, occasion their obliteration
and atrophy, a wasting and contraction of the entire organ being the
result. This condition attends the more advanced stages of Bright's
Disease, and is the sequence of the first-described form of the affection.
Dr. Johnson, from numerous examinations, has arrived at the inter-
esting and important conclusion, that the oily disease of the kidney is
generally coexistent with a similar affection of the liver, and even
with steatomatous deposition in the coats of the arteries, and to a
less extent with tubercular deposit in the lungs.
Dr. Johnson also maintains the opinion, that the oily deposition is
not preceded by any inflammatory or congestive stage : congestion
accompanies the disease; but this maybe either active or passive,
and when the latter, is produced by the pressure to which the vessels
are subject in consequence of the distention of the epithelial cells, and
which pressure gives rise to the effusion of serum and blood within
the tubes. These results are, however, the effects, and not the cause
of the disease.
The dropsy ensuing on scarlet fever, Dr. Johnson considers, does
not depend upon the presence of oil in the cells of the kidney; this
dropsy he regards as the result partly of the cutaneous disease, and
partly of the effort made by the kidneys to relieve the skin, the cir-
culation and functions of which are so much impaired.
From experiments made on cats, it appears that confinement in
dark chambers has the effect of inducing granular disease of the kid-
ney, accompanied by deposition of oil in the urine.
* "On the Minute Anatomy and Pathology of Bright's Disease of the Kidney, and
on the relation of the Renal Disease, to those Diseases of the Liver, Heart, and
Arteries with which it is commonly associated." George Johnson, M. D. — Medico-
Chirurgical Transactions, 1846.
GLANDS. 455
Dr. Johnson regards the existence of albuminous urine as quite a
secondary effect.
The results of Mr. Toynbee's investigation on the pathology of
Bright's Disease are very different, as we shall presently perceive,
from those of Dr. Johnson: both observers, however, agree in the
statement that there can be no doubt that albuminous urine often
exists, without any deposition of fat in the epithelial cells of the kid-
ney ; as in dropsy after scarlatina.
The following is Mr. Toynbee's own exposition of his researches
on the pathology of Bright's Disease:
" The First Stage of the Disease. — In this stage the kidney is enlarged, and innu-
merable black points are visible, which are the corpora Malpighiana dilated, and their
vessels distended with blood, seen through the capsule. The white spots, which
derive their appearance from the collection of fatty matter, begin to be perceptible.
" The peculiar features of this stage consist of an enlargement of the arteries enter-
ing the corpora Malpighiana; the dilatation of the vessels of the tuft, the capillaries
and the veins ; an increase in the size of the capsule of the corpus and of the tubuli,
and a large addition to the quantity of the parenchyma of the organ.
"The condition of the arteries is visibly changed, even at this early period; the
artery entering the corpus being actually twice or thrice its natural size; which is
the case also with the Malpighian tuft, and the capillary vessels which spring from
the tuft. An injection, in this stage, cannot very easily be made to pass through the
tuft, and fill the capsule of the corpus — a circumstance which almost always attends
injection in the later stages of the disease.
" The capillaries and veins are greatly enlarged, giving to the surface of the organ
the resemblance of net-work. This is the commencement of the stellated condition,
which is so marked a characteristic of the next stage of the complaint.
"The tubuli in this stage are also much increased in their dimensions; but the fat
which is found in them is soft and white.
" The Second Stage of the Disease. — The organ in this stage is very greatly
increased in size, its surface is smooth, and presents numerous white spots; the cap-
sule is but slightly adherent to the surface, and the tissue of the organ is flabby.
"The structural changes exhibited during this stage are the following:
" 1st. The artery of the corpus Malpighianum becomes so greatly enlarged, that
frequently it equals the dimensions of the tube itself, and is eight or ten times its
natural size. - It is tortuous and dilated, and sometimes, previously to entering the
capsule of the corpus, presents swellings analogous to those of varicose veins. The
primary branches of it, in forming the tuft, are also distended to ten or fifteen times
their natural size, and are not unfrequently discovered external to the capsule sof the
corpus, as though thrust out by some internal force. The vessels forming the tuft
are likewise enormously enlarged, and very often the minutest branches are fully as
large as the main artery of the corpus in a healthy state.
"Occasionally the tuft is broken up, and, instead of forming a compact mass, exhib-
its its individual branches separated from each other. At other times the branches
of the tuft are actually larger than the primitive artery of the corpus. Under these
456 THE SOLIDS.
circumstances it is singular that Mr. Bowman should have made the following remarks
' Though I have examined with great care many kidneys at this stage of the complaint,
I have never seen, in any instance, a clearly dilated condition of the Malpighian tuft
of vessels :' he adds, ' on the contrary, my friend Mr. Busk, an excellent observer, has
specimens which undoubtedly prove these tufts not to be dilated in the present stage:
and I possess injected specimens showing them in all stages, but never above their
natural size.' — It is very possible that the peculiar injection used by Mr. Bowman
may account for the fact which he mentions ; and this conjecture is rendered ex-
tremely probable, as in the later stages of the disease, the Malpighian tuft becomes
pressed upon by the adipose accumulation within, and, after undergoing compression,
will permit the fluid used in the process of double injection to pass through rather
than yield and distend. There are instances, again, in which the tufts are not
enlarged, but appear healthy, even in organs otherwise extensively diseased : but it
is important to add that these tufts, both in the second and third stages, when but
slightly enlarged, or even not enlarged at all, will offer free passage to the injection,
on the most gentle pressure, without even distending the whole of their vessels, and
thus indicate their diseased condition.
" An enlargement of the renal arteries and dilatation of their branches, are also
observable in this 'stage of the disorder.
"The capsule of the corpus, too, is in this stage very greatly increased in size, and
during the process of injection becomes frequently filled with the injection thrown
into the arterial system.
" The tubuli differ considerably from their healthy condition, being enlarged to
two or three times their natural size, and aggregated together in masses, so as to lie
in contact with each other, and form definite, roundish bodies: they are also
extremely convoluted with numerous dilatations : frequently they are varicose. At
other times they present distinct aneurismal sacs, which bulge out from one part of
the wall of the tube, to which they are attached by a small neck or pedicle. Occa-
sionally, some of the vessels of a convolution are smaller than the others, and their
size nearly natural. The tubuli in the masses are so closely packed that the blood-
vessels are evidently compressed, and rendered incapable of admitting an injection. At
times, a tube, even at some distance from the corpus, becomes very convoluted and
knotted into a mass.
" Parenchyma. — In cases where the kidney is much enlarged, the parenchymatous
cells will be found not merely increased in size, but adipose deposition will be visible
throughout them.
" The Third Stage of the Disease. — The kidneys are smaller than their natural
size; hard, white granules are prominent on their surface, which is' more or less
lobulated; the capsule is adherent; vesicles of large size are frequently every where
interspersed, and numbers of smaller ones stud the whole surface. On making a
section, the organ is found to be deprived of blood ; the cortical part contracted, the
blood-vessels large and their walls thick.
" Arteries. — The arteries are in a more contracted condition than that described in
the second stage; and the Malpighian tuft is often so changed from its natural state,
that the greater part of its vessels are not capable of being injected.
" The capsule of the corpus has assumed a more contracted appearance.
"The arteries in this stage are so difficult to inject, that some anatomists have
GLANDS. 457
denied the possibility of the operation. The difficulty has its origin in the great
pressure, which is exerted on the whole of the arterial system, by the contraction and
hardening of the organ.
" Veins. — The veins in this stage present, on the surface of the organ, the well
known stellated aspect which arises from the gradual pressure exerted on the trunks
and the contraction of the organ:
" Tubuli. — The tubuli are larger than in the preceding stage, and are gathered into
rounded masses, which form the granules on the surface of the organ. The latter
are of a white hue, and are most commonly fully distended with fatty depositions;
though not unfrequently they appear like dark spots ; the tubuli, in that case, being
full of blood. A rounded appearance is generally characteristic of the granules, in
each of which the component tubule forms innumerable convolutions. It is extremely
difficult to inject the tubuli from the ureter; indeed, it is very rarely that it is possible
to distend them from this source ; nor is it an easy matter to fill them from the artery,
though, as will be seen by the drawings, my efforts have not been without success.
" The tubuli are filled with oily cells, granular matter, particles of various sizes, and
blood globules.
" Parenchyma. — The parenchyma is hard, and is composed of elongated stellated
cells, from the angles of which fine threads proceed, and communicate with each other."
The researches of Mr. Simon and Dr. Johnson, which appeared
simultaneously in the " Transactions of the Medico-Chirurgical Soci-
ety" for 1847, have brought to light other facts in the pathology of
the kidneys. It is proposed in the next place to give an abstract of
the observations of each of these observers, couched, as far as possi-
ble, in the language of the authors.
Mr. Simon's paper is entitled "On Sub-acute Inflammation of the
Kidney."
"Without dwelling on those excessively rare cases, where idiopathic nephritis
(independent of tubercles or of calculus) may, by its mere intensity, have ended in
large suppuration or (almost uniquely) in gangrene, I may state that, in an infinite
majority of instances, inflammation of the kidneys is sub-acute. It depends on some
humoral derangement of the entire system, and commences as functional excitement
manifest in an act of over-secretion. The morbid material which thus stimulates the
kidney in its struggle for elimination will sometimes consist of products of faulty
digestion — thelithates or the oxalates; sometimes of matters cast upon the kidney
in consequence of suppressed function in other organs — the skin, or the liver; some-
times will be the mysterious ferment of a fever poison — typhus, or scarlatina. In these
several cases, whatever variety may exist in the detail of their causation, the essential
symptoms during life, and the essential anatomical changes, are strictly identical in
kind. They vary only in degree. The maleries morbi seeks to effect its discharge by
means of an increased activity in the secreting functions of the kidney: it stimulates
it; and the result of the stimulation is not so much an increase of the watery secre-
tion as it is an augmented cell growth in the tubules of the gland. This accel-
eration of function is incompatible with maturity of the secreted products; the
458 THE SOLIDS.
epithelial cells undergo various arrests or modifications of development, and become
more or less palpably imbued with evidences of inflammation.
. "If attention happen to be directed to the state of the urine, that fluid will be found
to present manifest signs of derangement. Microscopical examination will show in
it numerous nucleated cells, which, in the hurry of over-secretion, have descended
from the urinary tubules. Many free cytoblasts will likewise generally present them-
selves, together with a variety of those indefinite shapes which are known to the
Morphologist as abortions of cell-growth, and which constitute a series of connecting
forms between the pus globule and the healthy gland cell. Mingled with these, in
greater or less quantity, will be noticed also those remarkable fibrinous threads first
described by Dr. Franz Simon in connexion with renal disease. They are seen as
exceedingly delicate, almost perfectly transparent and colourless cylinders, often con-
taining in their mass some of the cell forms just enumerated, or, not unusually, a few
blood discs, resulting from haemorrhage into the tubules.
"On several occasions, where the renal irritation has been gouty, I have seen
crystals of lithic acid thus entangled in fibrin : in other cases, though far less fre-
quently, I have distinguished crystals of oxalate of lime similarly enveloped. It is
well known that these little cylinders are fibrinous moulds of the inflamed urinary
tubules, some of the other contents of which they bring with them in their descent.
They are thus quite as characteristic of the disease they attend as croupy expectora-
tion is of tracheitis ; and the cells or crystals included in them often afford the most
valuable therapeutical indications.
"If patients chance to die while their urine is first furnishing the signs enumerated,
it will often happen that the kidneys, in their general appearance, present no marked
deviation from healthiness. Their cortical substance may, indeed, show the minute
blood dots of intra-tubular haemorrhage ; or, more rarely, may present here and there
a pin-head abscess. But often, perhaps most often, a superficial observer would pro-
nounce the kidneys healthy; and, unless previous knowledge of the albuminuria had
existed, they would receive no farther attention; or the Case-Book might contain that
vaguest of all vague records — ' slight congestion of the kidney.'
"On minuter analysis, however, the microscope will reveal a large amount of
disease. The ultimate tubules are found, as one might anticipate, gorged with an
uneliminable excess of crude and vitiated secretion. Blood and amorphous matter, and
an infinite range of cell-growth, from pus globules to the healthy germination of the
gland, present themselves in various combinations; and among them shape or colour
will sometimes enable us to discern the specific cause of the derangement — crystals
of lithic acid or of oxalate of lime, or the ochreous tinting of bile. By products
such as these the tubes are plugged, irregularly distended, and not unfrequently
burst and annihilated. So close is the compaction of material, even in many of
those tubes that have no shaped inflammatory products within them, that they are
plainly impervious ; and it is only by artificial means — by further tearing of the frag-
ment, or by use of chemical agents, that we can satisfy ourselves that the dense plug
in question consists but of agglomerated gland cells.
"Now, in the posl mortem examination of these chronic cases, we may or may not
find the kidneys materially contracted and deformed. It happens, to say the least,
very frequently that the organ has preserved its full size, and presents the ordinary
colours. Perhaps it may have a cyst or two on its surface. Between such kidneys
GLANDS. 459
and those which are all knobbed and puckered and wrinkled, there is not the essen-
tial difference which first sight would suggest. I shall first detail the changes which
are latent in the healthier-looking kidney, and subsequently shall consider the
anatomy of the contracted specimens, and analyze the circumstances which deter-
mine that apparent atrophy of the gland.
"In the first instance, then: In commencing the microscopical examination of the
cortical substance, we partially find a similar state of tubes to that described in con-
nexion with the sub-acute attack — a state, namely, of unequal distention and of
blocking up by their own accumulated products. In the cases which have lasted
a long time, these products will often be found to have undergone material altera-
tions, from the combined effects of pressure and absorption. The contents of the
epithelial cells will have lost much of their natural fine granularity; so that the cells
will appear, even when viewed singly, to have acquired a marked increase of solidity
and substance. But, more than this: in many parts hardly a trace of tubularity will
be found; the tubes have been burst; their contents have been interfused amid the
matrix and blood-vessels; and their debris may be found on opposite sides of a
preparation — here black and bloated, there pale and collapsed.
" Between these trophies of disease there is a new manifestation. The interspace
is crowded with a profuse development of cysts, apparently foreign to the healthy
structure of the part. They are of all sizes; some are visible to the naked eye;
some are of the magnitude of normal gland cells, tW-two > but the majority are of
an intermediate bulk, ^ 4-Wo- Even where smallest, they are distinguished by their
sharp outline; and the larger ones are conspicuous by their roundness and trans-
parency, for all above ~± have predominantly fluid contents.
"To explain this very remarkable phenomenon, I take leave to digress for a
moment from the straight-forward pursuit of the inflammatory changes. Any one who
has made a dozen jiost-mortem examinations must have observed cysts in the kidney;
and there can be few pathologists who have not speculated on the origin of these
growths. Their connexion with chronic obstructive diseases of the kidney being
notorious, some observers have supposed them to originate in dilatation of the Mal-
pighian capsules; while others have referred them to distention of the urinary tubules.
They exhibit great variety in size; they are seen every day as small as mustard-seeds;
they have been seen as large as cocoa-nuts. Thus, they obviously range from a very
conspicuous largeness to a size at which the naked eye loses them. On microscopical
examination of cysted kidneys, the same uninterrupted gradation of size is seen to
repeat itself. The larger vesicles fill the field of the microscope; the smaller ones
diminish progressively, so that scores of them may be in the field at the same time.
"A section of cysted kidney, carefully examined with a sufficent magnifying power,
may show an astonishing number of these minute vesicles; a number quite dispropor-
tionate to that of the larger cysts visible to the naked eye; so that, sometimes, by a
single one of the latter class seen on the surface of the kidney, I have found myself
guided to a disease which is substantially a vesicular transformation of the ultimate
structure of the gland. The smallest cysts are simple nucleated cells, of the same
size (or rather within the same limits of size) as the common secretory, or epithelial
cells of the gland. From these cells they seem to be distinguished by their very
definite outlines, and by their transparent fluid contents : but a step further in micro-
scopical analysis shows that the distinction ceases at this point. They show no signs
460 THE SOLIDS.
of a specific origin; no germs can be found for them other than might equally belong
to epithelial development; it seems as though from the same germs — according, no
doubt, to varying influences — healthy gland cells might grow, or these fluid-hold-
ing cysts.
"Fuller investigation of the specimen reveals the following very suggestive fact:
the copious formation of cells occupies J,he place of tubes, holding their relation to
the vascular plexus of the gland; and, as one gets to the periphery of the portion of
gland thus transfigured, one finds the broken extremities of the original tubules —
some empty and collapsed, others obstructed and often dilated with morbid accumula-
tion. In some cases, this obstructive material contains a large proportion of fat, or
consists of it almost entirely.
" In short, in pursuing the minute anatomy of the cysted kidney, we are conducted
back to that same structural change which we found in connexion with sub-acute
nephritis, and demonstrably dependent on inflammatory processes; or sometimes we
are led to a change in some respects similar to this, associated with what is known as
the mottled condition of the kidney.
"The pathology of cysted kidney may accordingly be traced in either of two direc-
tions; from its first causation, or from its extreme phenomena. Following the latter
course, we have ascended to a period in the history of cysts, in which they lie with
numberless gland-germs amid the remnants of broken tubules. The unbroken
tubules around show no growth of such cysts in then- interior ; many are distended,
it is true, but not with cysts ; their distention is of a kind that we have already inves-
tigated— inflammatory, or perhaps fatty. From the smallness attained by the cysts, it
seems quite obvious to me, that they cannot commence in any transformation of the
tubes themselves or of the Malpighian capsules. Accordingly, I find the same
theory suggested by this method of inquiry, as when the morbid change had been
traced descensiveiy from its causes, viz : that certain diseases of the kidney (whereof
sub-acute inflammation is by far the most frequent) tend to produce a blocking up of
the tubes: that this obstruction, directly or indirectly, produces rupture of the limits
ary membrane; and that then, what should have been the intra-tubular cell-growth
continues with certain modifications as a parenchytic development.
"During the growth of the cysts, they frequently exhibit an endogenous formation
of cells which line them as an epithelium.
"If I am right in my statement of facts, and if my theory of the cyst-growth is
sound, then the early stages of the process are certainly points of great interest : for
no one accustomed to the interpretation of nature, can doubt the reparative tendency
of these acts. The effused gland-genns are the last phenomena of the original dis-
ease, and the first of the attempted compensation. The transparent nucleated cysts,
with their clear, sharp outlines, are not mere dropsical epithelia ; but are organized
for secretion into their own cavities, so as at least to withdraw from the blood, if they
cannot eliminate from the body, the materials which fill them.
" Returning now to the traces of inflammation in an uncontracted kidney, we have
yet to ascertain the condition of its blood-vessels. Numbers of the Malpighian
bodies are extinct for all purposes of secretion : their vessels obliterated, their cap-
sules wrinkled round them; they are dwindled, opaque and bloodless. Sometimes
the contraction of the Malpighian bodies is secondary on that rupture of their capil-
laries which Mr. Bowman has indicated as the source of intra-tubular haemorrhage;
GLANDS. 4G1
which rupture, of course, may have arisen either in an augmented impulse of the
arterial stream which fills them, or in an impeded circulation through the venus plexus
into which they discharge themselves. But rupture of the capillaries is not the only
cause of atrophy, to which these bodies are liable in the disease under consideration.
The vascular tufts may be exposed to injurious pressure from materials accumu-
lated in their capsules. Thus, I have seen them flattened into a fourth of their
natural compass, while the remaining larger portion of the capsule (probably con-
tinuous with an obstructed tubule) has been distended with a colourless and
transparent fluid.
" Such is the minute anatomy of a kidney, which, having suffused from sub-acute
inflammation, has undergone, in consequence, no noticeable alteration of volume,
although having in its interior a very considerable new development.
"If the pathology of the uncontiacted kidney be rightly understood, that of the
contracted specimen will follow it naturally. It seems to me that, in the mere
destruction and absorption of tissues, there is abundant explanation of the shrunken
dimensions of a kidney which has passed through inflammatory changes. The tubes
have burst, and a great portion of their contents has been removed by absorption ; the
Malpighian bodies have dwindled to a few; what, then, remains to make bulk? In
the uncontracted specimen a false appearance of size is maintained by the adventi-
tious cyst-growth, which I have described as filling the interstices of the organ. But
the cysts are so much over and above the real kidney-structure ; and if that succulent
surplus could be removed, the result, as I have suggested, would be the falling
together of wasted textures into a comparatively small compass. The cause of
shrinking in the gland is the gradual absorption of spoiled material. This cause
operates equally in all chronic cases, and its effects are to be traced in the uncon-
tracted, as in the contracted specimen. The main difference between these two lies
in the more or less of interstitial cyst-development; the most dwindled are those in
which least of the newr growth has arisen or has survived.
" I see no reason for believing that the interstitial effusion of lymph effects much
towards the final contraction of the kidney. There are not wanting, I know, some
pathologists who will assert it to be the great agent in the change ; and who conceive
they have seen the whole process of fibre-formation, according to the most approved
foreign cell-theories. But I suspect that the observers of new fibre will often have
confounded cause and effect. Coincidently with atrophy of the kidney, there occurs
a contraction of the reticular matrix; but that contraction is, probably, consequent on
a prior absorption of the intervening tissue. The meshes of the matrix come nearer
together, and, in a given space, there is an excess of fibrous tissue, only because the
material is withdrawn, which originally expanded that matrix through three times the
space it now7 occupies.
" Up to the present point, I have studiously avoided introducing the ambiguous and
controversial name of 'Bright's Disease.' And now it will probably be asked, what
relation to Bright's Disease is borne by the malady I have treated of? Is it the same
thing under another name? This question can be answered in a word, only when it
shall have been settled what Bright's Disease really is. The history of the complaint
or complaints, included under that title, was, perhaps, originally systematized with too
much haste. Starting from dropsy with albuminuria, _and noticing that two chief
forms of morbid appearance corresponded to that symptom (one, namely, where the
462 THE SOLIDS.
kidney was large and mottled ; the other, where it was contracted and knobbed, or
irregularly granular), pathologists have considered these two forms as representing
the extreme stages of one and the same disease.
"I must venture to express a doubt as to the justice of this generalization. After
investigating both classes extensively, I am convinced that the mottled and the con-
tracted kidney do, in almost every instance, belong to different morbid actions ; not to
different stages of the same.
"The mottled kidneys, in an infinitely large proportion of cases, remain large and
mottled to the end.
"I have now little further to add; with respect to the symptoms of sub-acute
inflammation of the kidney, I will make one observation in addition to those already
embodied in my paper. The descent of epithelium and its germs with the urine ;
the presence of albumen there, and sometimes of blood; the little casts of the
tubules — sometimes wrought of fibrin, sometimes of compressed epithelium; —
these signs belong equally to the sub-acute inflammation and to the scrofulous
disease. They are signals simply of renal irritation, whether from one cause or the
other, and I suspect they only attend the scrofulous disease at that stage of its
progress in which sub-acute inflammatory action is superadded to the primary fatty
degeneration. Dr. Johnson's accurate observation has enabled us, under most cir-
cumstances, to diagnose the two classes from each other; for, in the scrofulous
disease there will be always seen, as he describes, more or less oil entangled in the
fibrinous casts, or gorging the cells which descend in the urine; a phenomenon which
does not belong to the pure sub-acute inflammation."
The* following pages embrace the more important portions of Dr.
Johnson's communication, which is entitled, "On the Inflammatory
Diseases of the Kidney:"
"In a paper published in the last volume of the 'Society's Transactions,' I gave
some account of fatty degeneration of the kidney, and declared my intention to make
the inflammatory diseases the subject of a separate communication. On the present
occasion, I purpose to bring before the Society the result of some observations on
this very interesting and important subject.
" In the paper before alluded to, when referring to the condition of the kidney,
which occurs as a consequence of scarlatina, I stated that " it is, in fact, an inflamma-
tion of the kidney, excited, like the inflammation of the skin which constitutes the
eruption of scarlatina, by the passage through the part of the peculiar fever-poison;
and as the inflammation of the skin terminates in an excessive development of
epidermis, and a desquamation of the surface, so the inflammation of the kidney
excites an increased development of the epithelium which lines the urinary tubules-
this material partly accumulates in and chokes up the tubes, while part of it becomes
washed out with the urine, and may be detected in large quantities in that fluid by
the aid of the microscope.
" To the account then given, which I believe to be essentially correct, subsequent
observations enable me to make some important additions.
"On a microscopical examination, the convoluted tubes are seen filled in different
degrees with nucleated cells, differing in no essential character from those which line
GLANDS. 4G3
the tubes of the healthy gland. The chief difference between these cells, which are
the product of inflammation, and those which exist in health, consists in the former
being generally of smaller size and more opaque and dense in their texture. It is very
interesting and important to observe that, while the convoluted tubes are rendered
opaque by this accumulation of cells in their interior, the Malpighian bodies are trans-
parent and apparently quite healthy. The straight tubes which form the pyramids also
contain an increased number of cells; but there is reason to believe, that these cells
are not formed in these portions of the tubes, but that they are lodged there in their
passage from the convoluted through the straight tubes; the latter being merely
ducts leading into the pelvis of the kidney. Some of the tubes contain blood, which
has, doubtless, escaped from the gorged Malpighian vessels lying within the dilated
extremities of the tubes. There is no deposit outside the tubes. The essential
changes in the kidney are an increased fullness of the blood-vessels, and an abundant
development of epithelial cells, differing slightly in general appearance, size, and
consistence, from the normal renal cells; this increased cell-development occurring
in those portions of the urinary tubules, the office of which, as Mr. Bowman has
suggested, is to excrete the peculiar saline constituents of the urine, while the Mal-
pighian bodies, whose office is the separation of the water, are unaffected.
" The condition of the urine in these cases, is clearly indicative of the changes
occurring in the kidney. After the urine has been allowed to stand for a short time,
a sediment forms, and, on placing a portion of this under the microscope, there may
be seen blood corpuscles, with epithelial cells in great numbers, partly free and partly
entangled in cylindrical fibrinous casts of the urinary tubes; and, very commonly,
numerous crystals of lithic acid are present. As the disease subsides, which, under
proper treatment, it usually does in a few days, the blood, fibrinous casts, and
epithelial cells, diminish in quantity, and finally disappear; but traces of the casts
and cells are still visible some days after the urine has ceased to coagulate on the
application of heat or nitric acid.
" The casts and cells which appear in the urine, when the disease is subsiding, are
such as have remained some time in the urinary tubes before they have become
washed out by the current of fluid poured into the tubes from the Malpighian bodies;
many of the cells entangled in these casts have, consequently, become disintegrated
and broken up into amorphous granular masses; thus presenting appearances which I
shall presently show are characteristic of the casts occurring in cases of chronic
nephritis. Such is the morbid anatomy of the kidney, and such are the characters of
the urine occurring as a consequence of scarlatina.
"To the form of renal disease here described as occurring in connexion with
scarlatina, I propose to give the name of ' acute desquamalice nephritis.''
"The next form of inflammatory disease, to which I would direct attention, is one
of great interest and importance. Two drawings by Mr. Westmacott represent the
disease in two different stages ; one represents a kidney in the earlier stage ; the
other shows a more advanced stage of the same disease. The kidney is never much
enlarged ; in the earlier stage, the size of the organ is natural, and the structure of
the cortical portion appears confused, as if from the admixture of some abnormal
product; there is also some increase of vascularity. As the disease advances, the
cortical portion gradually wastes; the entire organ becomes contracted, firm, and
granular; the pyramidal bodies remaining comparatively unaffected even in the most
4G4 THE SOLIDS.
advanced stages: simultaneously with the diminution in size of the kidney, there is a
decrease of vascularity. These changes occur very gradually ; the disease is essen-
tially chronic, having a duration in most cases of many months, and in some even of
several years. It is almost confined to persons who are in the habit of partaking
freely of fermented liquors; it is very commonly seen in those who have suffered
from gout, and is not uncommon in those who, having indulged freely in the use of
fermented liquors, have yet never had an attack of gout. It is sometimes, but I
believe rarely, met with in those whose mode of life has been strictly temperate and
abstemious. The symptoms usually attending the disease, are the following: —
dropsy, which commonly is not excessive, often coming on only in the most advanced
stages, and sometimes being entirely absent throughout the entire progress of the
disease. The urine is commonly albuminous: it seldom, however, contains a very
large quantity of albumen, and sometimes there is no coagulation on the addition of
heat or nitric acid. The urine is sometimes high-coloured and scanty; but in most
cases, it is rather abundant, pale, and of low specific gravity — from 1005 to 1010. In
some instances, the quantity of urine is much greater than in health, and this increased
quantity of urine is secreted by kidneys which are found after death to be contracted
to one-third of their original bulk. In urine of such low specific gravity, there is, of
course, a deficiency of the solid constituents, while the blood, which is much changed
and impoverished, contains an excess of these materials.
" On a microscopical examination of the kidney, the nature of the above-mentioned
changes is very clearly revealed, and at the same time, the attending symptoms are
satisfactorily explained. My account of these phenomena will be rendered more
intelligible, if I give the facts and their explanation at the same time.
"On placing thin sections of the kidney under the microscope, some of the tubes
are seen to be in precisely the same condition as in a case of acute desquamative
nephritis : they are filled and rendered opaque by an accumulation within them of
nucleated cells, differing in no essential respect from the normal epithelium of the
kidney : this increase in the number, and this slight alteration in the character, of the
epithelial cells, are the result of the elimination, by the kidney, of mal-assimilated
products, which are being continually developed in these gouty and intemperate
subjects, and which are not normal constituents of the renal secretion.
" There must evidently be a certain limit to the number of cells which can be
formed in any one of the urinary tubes; for, although some of the cells escape with
the liquid part of the secretion, and so may be seen in the urine, as in a case of acute
desquamative nephritis, yet, in many of the tubes, the cells become so closely packed,
that the further formation of cells is impossible, and the process of cell-development,
and, consequently, of secretion within that tube, are arrested. The cells, thus formed
and filling up the tube, gradually decay, and become more or less disintegrated.
While these changes are going on in the convoluted portions of the tubes, the Mal-
pighian bodies remain quite healthy, the Malpighian capsules for the most part
transparent, and the vessels in their interior are perfect. From these vessels, water,
with some albumen and coagulable matter, is continually being poured into the tubes ;
and, as a consequence of this, the disintegrated epithelial cells are washed out by the
current of liquid flowing through the tubes so that, on examining the sedimentary
portion of the urine, we find in it cylindrical moulds of the urinary tubes composed
of epithelium in different degrees of disintegration, and rendered coherent by the
GLANDS. 405
fibrinous matter which coagulates among its particles. The appearance of these
casts are quite characteristic of this form of 'chronic desquamative nephritis.'
"There is reason to believe, that when the process of cell-development and of
secretion have once been arrested, by the tube becoming filled with its accumulated
contents, it never recovers its lining of normal epithelial cells; but, when the disin-
tegrated epithelium has become washed away from the interior of the tube, the
basement membrane may be seen, in some cases, entirely denuded of epithelium; in
other cases, a few granular particles of the old decayed epithelium remain: and again,
in other instances, the interior of a tube, which has been deprived of its proper
glandular epithelium, is seen lined by small delicate transparent cells, very similar to
those which may sometimes be seen covering the vessels of the Malpighian tuft.
"It now becomes interesting to ascertain what further change the tube undergoes,
after having lost its normal epithelium. It is quite certain that, as a general rule, the
Malpighian bodies remain unaffected, both in structure and in their office of secreting
the watery constituents of the urine, until the whole of the disintegrated epithelium
lias been washed out of the tubes. Of this there are two proofs ; the first is the fact
of a very long convoluted tube having its contents completely washed out, and its
bnaement membrane left quite naked: this could happen only as a consequence of a
current of liquid passing through the tube, and there is no known source of such a
current but the Malpighian vessels : the second proof is still more convincing and
satisfactory, and it is this — that a tube may often be seen entirely denuded of its
epithelial lining, and continuous with a Malpighian body, in the interior of which the
vessels are quite perfect.
" Now, a tube of this kind, deprived of its lining of normal epithelium, has manifestly
lost its power of separating from the blood the solid constituents of the urine, while
the Malpighian vessels remaining unaffected, the power of secreting water remains.
Further, it appears probable not only that the Malpighian body continues to secrete
water, but that the whole length of a convoluted tube thus deprived of its proper
epithelium, and either remaining naked or lined by delicate nucleated cells, such as
those which cover the Malpighian vessels — that the entire length of such a tube
becomes a secretor of water, which it abstracts from the portal plexus of vessels on
its exterior. This is rendered probable by the appearance of the tube itself; and the
probability is still further increased by the fact of the tubes becoming, in some cases,
dilated into cysts, which usually contain a simple serous fluid, without any of the solid
constituents of the urine.
" It has long been supposed that the simple cysts, which are so commonly seen in
connexion with some forms of renal disease, are, in fact, dilatations of the urinary
tubes. I am not aware that any satisfactory evidence has been adduced in confirma-
tion of this opinion, but there are some facts and arguments which appear to me
abundantly sufficient to prove the accuracy of the notion.
" 1 st. The tubes thus denuded of their epithelium are often seen much dilated. I
have repeatedly seen them three or four times exceeding their normal diameter. In
some cases the dilatation is very sudden, so that the tube assumes a globular form,
and appears to bulge in the intervals of the fibro-cellular tissue, in which the tubes
are packed: in some cases, too, the basement membrane appears thickened in propor-
tion to the dilatation of its cavity. Now, this process of dilatation having once com-
menced, and the lower end of the tube becoming closed by a deposit in its interior, or
30
466 THE SOLIDS.
by pressure from without, there is no reason to suppose that the process may not
continue until a cyst as large as a pea or a walnut is formed.
"2dly. But there are other facts which afford a very interesting and remarkable
confirmation of this notion. In a case of simple acute or chronic nephritis, the
quantity of oil in the secreting cells of the kidney is very small; sometimes, indeed,
none can be detected. But it frequently happens that, after a tube has been stripped
of its secreting cells in the manner before mentioned, an accumulation of fatty mat-
ter occurs in its interior, the denuded basement membrane becomes scattered over
with separate oil globules, and these increase in size until they form masses of fatty
matter, having much the appearance of adipose tissue; and such a mass is frequently
washed out from the tube, and may be detected in the urine. This occasional filling
of the tube with fatty matter is very interesting in connexion with the fact, that in
some cases the cysts, which are supposed to be dilated tubes, are also found filled
with the same material. In two cases, I have found a cyst as large as a hazel-nut,
quite full of oil, presenting all the characters of that seen in the tubes which have
lost their epithelium in consequence of chronic inflammation.
"The evidence, then, of the simple serous cysts being dilated tubes, is the follow-
ing:— 1st. That tubes are often seen much dilated and thickened. 2d. As the
inner surface of the tubes has the appearance of being endowed with the power of
secreting water, so the cysts usually contain a simple serous fluid. 3d. As an accu-
mulation of oil occasionally occurs in the tubes, so the cysts are in some instances
filled with the same material. 4th. There is no reason to suppose that these cysts
have any other origin. It appears probable that the Malpighian bodies could not
become dilated into cysts, because an accumulation of liquid within the Malpighian
capsule would necessarily compress and obliterate the vessels of the Malpighian tuft
and so would cut off the further supply of fluid.
" Another change consequent upon the destruction of the cells which line the
urinary tubes is, a diminished supply of blood, and a gradual wasting of the tube.
I have already shown that there must be a close connexion between an increased
development of epithelial cells, and an increased afflux of blood to the part. This is
well seen in a case of acute desquamative nephritis, and vice versa, a more or less com-
plete destruction of the epithelial cells will be attended by a corresponding diminished
afflux of blood, and a consequent atrophy of the part affected. In every kidney
which has been the subject of chronic inflammation, there may be seen tubes con-
tracted in different degrees, as a consequence of the destruction of their epithelial
lining; in some instances, the basement membrane becomes folded, and presents an
appearance not veiy unlike white fibrous tissue. As a consequence of this wasting
of successive sets of tubes, there is a gradual diminution in the bulk of the cortical
portion of kidney, until, at length, the entire organ becomes small, contracted, and
granular. When a thin section of a kidney, thus atrophied, is placed under the
microscope, there may be seen an abundance of fibrous tissue; and this has often
been described as new fibrous tissue developed during the progress of the disease:
whereas it is, in reality, nothing more than the atrophied remains of the basement
membrane of the tubes, with the healthy fibrous tissue arranged in the form of a
net-work in which the tubes are packed, and which now appears more abundant in
consequence of the wasting of the tubes.
"It has already been stated that the Malpighian bodies are unaffected in the
GLANDS. 467
progress of this disease; and this is true, in so far as they remain, for the most part,
free from any deposit or accumulation in their interior; but they must necessarily be
affected by the changes occurring in other parts of the organ. Thus, the destruction
of many of the Malpighian bodies is a necessary consequence of the simultaneous
wasting of the vessels and tubes which occurs in the advanced stages of chronic
nephritis: and, during the progress of the disease, the vessels of the Malpighian tuft
will be in a state of more or less active congestion, in proportion to the rapidity of
secretion and of cell development in the tubes ; and one consequence of this con-
gestion of the Malpighian bodies will be the escape of serum into the tubes, and the
mixture of albuminous matter with the urine. The quantity of albumen in the urine
will be great in proportion as the disease approaches in activity to that form which I
have called 'acute desquamative nephritis.' When the disease is chronic and inactive,
there may be no albumen in the urine, or, it may be present in quantities so small as
not to be detected by the ordinary chemical tests; In such cases, as, indeed, for the
accurate discrimination of all forms of renal disease, the microscope will be found an
invaluable aid. It must be remembered that the essential change in this disease *s a
destruction of the epithelial cells in the manner already described; the best evidence
of this change being in progress is, the presence in the urine of moulds of the urinary
tubes, composed of more or less disintegrated epithelium ; and such evidence I have
repeatedly obtained, when no albumen could be detected by the ordinary heat and
nitric acid tests.
"A sufficient explanation has already been given of the small quantity of the saline
constituents excreted by the kidneys in cases of chronic nephritis. It is manifest
that, if the epithelial cells are the agents by which the solid constituents of the urine are
separated from the blood, a deficient excretion of these materials will be a necessary
consequence of the greater or less destruction of the epithelial cells.
"Before concluding this communication on the inflammatory diseases of the kidney,
it appears desirable to allude very briefly to the subject of my last paper, viz: 'Fatty
Degeneration of the Kidney;' my object being to show how essentially distinct are
the two forms of disease ; and, at the same time, to explain the manner in which they
are sometimes combined.
"For some months past, I have been aware that fatty degeneration of the kidney,
occurs in two distinct forms.
" In the simple fatty degeneration of the kidney, all the tubes become almost
uniformly distended with oil. In a slight degree and in the earlier stages, it is often
found, after death, in cases where there is no reason to suspect that it has been pro-
ductive of any mischief during life: it is not until the fatty accumulation has attained
a certain amount, that the functions of the kidney are interfered with. It is this form
of fatty degeneration of the kidney which occurs in animals, as a consequence of
confinement in a dark room. In the human subject, although in the earlier stages, it
is a very common occurrence, yet in the more advanced stages it occurs less fre-
quently than the second form of fatly degeneration. This form of the disease is
represented in the 5th figure of Dr. Bright's 3d plate, as well as in the 1st, 2d, 5th,
and 6th figures of Rayer's 8th plate. The cortical portion of the kidney, to use the
words of Dr. Bright, is soft and pale, and interspersed with numerous small yellow
opaque specks. The kidney is generally enlarged; sometimes it is even double the
natural size. In some cases, the cortical portion is somewhat atrophied and granular;
4b8 THE SOLIDS.
but neither in this, nor in the first form of fatty degeneration of the kidney, does that
extreme wasting with granulation occur, which is so frequent a consequence of
chronic nephritis.
"On a microscopical examination, the convoluted tubes are found filled in different
degrees with oil; some tubes being quite free, while others are ruptured by the
great accumulation in their interior. The opaque yellow spots scattered throughout
the kidney, are neither more nor less than convoluted tubes distended, and many of
them ruptured by their accumulated fatty contents; just as the red spots are found
to be convoluted tubes filled with blood. The cells which contain the oil are for
the most part smaller, more transparent, and less irregular in their outline than the
ordinary healthy epithelium; they are increased in number, and many of them are so
distended with oil as to appear quite black. In parts of the same kidney, there
may commonly be seen some of the appearances already described as indicative of
desquamative nephritis. This form of disease is very commonly combined with fatty
degeneration of the liver; but less frequently than is the first form of fatty degenera-
tion of the kidney.
"The peculiarities of the second form of fatty degeneration of the kidney result
from a nephritic condition of the organ, dependent on the presence of some irritating
material in the blood being associated with a tendency to fatty degeneration; this
tendency resulting from the presence in the blood of mal-assimilated fatty matter.
The nephritic condition is manifest by an increase in the number of epithelial cells;
the tendency to fatty degeneration, by a filling of many of these with oil. Although
the two conditions are combined in this and in similar cases, it must be remembered
that they are essentially distinct in their nature and origin. Each cell which escapes
from the kidney carries with it a portion of the morbid material. The oil is in the
form of visible globules ; while the cells which contain no oil doubtless contain some
other material which is invisible, or less readily seen than the oil globules.
"I have now distinguished and described four conditions of the kidney:
"1st. Acute desquamative nephritis;
" 2d. Chronic desquamative nephritis ;
" 3d. Simple fatty degeneration ; and
" 4th. A combination of fatty degeneration with desquamative nephritis.
" The diagnosis of each of these conditions of the kidney, during the life of the
patient, is a matter of the greatest importance with reference to prognosis and treat-
ment; and the diagnosis maybe made with ease and certainty by a microscopical
examination of the nrine.
The most recent researches in this country into the patnological
anatomy of the kidneys are those of Dr Gairdner,* who has evidently
devoted to the elucidation of this subject not a little time and atten-
tion ; and the results of these investigations will now be given in as
concise a form as possible.
Dr. Gairdner treats of his subject under the three following heads:
1. Exudation; 2. Lesions affecting chiefly the vascular system ; and 3. Lesions of
the tubes and epithelium — an arrangement which will here be followed.
* "Contributions to the Pathology of the Kidney," by William T. Gairdner,
M. D. — Monthly Journal of Medical Science, 1848.
GLANDS. 469
Exudation.
Exudations into the substance of the kidney give rise to a great variety of
external appearances, which have been well figured and described in the works of
Bright and Rayer.
Exudations from the blood-vessels may have their seat in any, or all the tissues of
the kidney ; their usual situation, however, is in the interior of the tubes, but it also
occurs frequently within and around the Malpighian bodies, and in the inter-tubular
tissue, the tubes being quite clear; it is also seen infiltrated through all the tissues
in the form of a homogeneous mass, which contained within it the whole of the
anatomical elements of the kidney.
The appearance of the kidney, as altered by the presence of exudation in the tubes,
is subject to variations depending on the amount of the deposition, and its partial or
general character: one almost invariable effect of the repletion of the tubes, is a
corresponding diminution in the fullness of the vessels of the cortical substance,
particularly of the Malpighian vessels, and the capillaries surrounding the tubes.
This effect is evidently the result of pressure.
It is thus evident that Dr. Gairdner does not ascribe the albuminous urine of Bright's
Disease to secondary congestion, or rupture of the Malpighian bodies, caused by the
distension of the tubes from accumulated fat; and in this particular his views differ
from those already cited of Dr. George Johnson.
The volume and weight of kidneys containing exudation in the tubes are frequently
much increased.
The exudation may be diffused throughout the organ, or it may be confined to
certain portions of it. " It then tends," writes Dr. Gairdner, " to accumulate in cer-
tain sets of the convolutions in which the urinary current is least active. These
becoming partially blocked up, and ceasing entirely to secrete, are thrown aside from
the outward current of secretion, and become a centre of attraction for further
deposit, just as the eddies and still waters at the sides of a rapid stream receive from
it the foam and floating bodies brought down from above. In this way, more and
more of the adjacent loops of tubuli are filled with the abnormal deposit, and become
added to the former nucleus, until the masses of exudation, thus imprisoned within
tubules through which no secretion passes, form irregularly rounded bodies in the
cortical substance, visible to the naked eye, more or less prominent on the surface of
the organ, and usually of an opaque yellowish colour. These are the granulations
first described by Dr. Bright."
Intra-tubular exudations, including tubercular and cancerous deposits, may be con-
sidered under three heads : a, crystalline or saline matters deposited from the urine ;
b, oleo-albuminous, or granular' exudations from the blood plasma; c, exudations
forming pus.
a. The most common saline deposit met with in the tubes of the kidney is the
amorphous urata of ammonia ; inasmuch as this salt is a constituent of healthy urine,
its presence in moderate quantities is merely a normal post-mortem appearance, the
deposition of the salt resulting from the cooling of the urine after death. In some
instances, however, it is present in such large quantities, and in these it occasions such
an alteration in the appearance of the kidney, that it might, unless discriminated by
means of the microscope, be attributed to disease.
470 THE SOLIDS.
Under the microscope, the urate of ammonia presents the appearance, when within
the tubes, of a fine molecular shading which entirely obscures the nuclei ; the dis-
tinguishing character of this deposit is its ready solubility in the dilute acids, as the
acetic or nitric.
In one case Dr. Gairdner detected the presence of crystals in the tubes, which, from
their appearance and colour, he entertained little doubt were of uric acid, although,
from their minute quantity, they could not be submitted to chemical examination.
In this case the urine was of low specific gravity, and albuminous, although there
was no apparent exudation within the substance of the gland.
b. Dr. Gairdner includes under the term " oleo-albuminous exudations from the
blood plasma," those exudations which are fatty in their nature, as well as the inflam-
mation globules, granular corpuscles, or exudation granules, and corpuscles of differ-
ent writers.
The facts connected with the presence of fatty exudations in the kidney, have been
almost exhausted by the excellent reasearches of Dr. Johnson ; one additional fact
of interest has been added by Dr. Gairdner. This observer finds that the fatty
granules or globules are not confined to the epithelial cells, but also that they may
be freely disseminated throughout the tubes: the tubes containing the fatty granules
sometimes appear distended, at other tunes smaller than natural, as if they had con-
tracted around the fat.
It is probable that the presence of the fatty globules in the tubes results from the
rupture and disorganization of the cells which first contained them, and that, there-
fore, their location in the tubes themselves indicates a more advanced condition of
this form of renal disorganization.
c. The occurrence in the cortical substance of deposits of pus is not very uncom-
mon : their most usual form is that of small abscesses, rarely exceeding the size of a
pea, and frequently much smaller; sometimes confluent, and irregularly disseminated
throughout the cortical substance.
The granular (oleo-albuminous) form of exudation is frequently found occupying
the tubes of the kidney, and occasionally also within the capsules of the Malpighian
bodies : when in large quantity in the latter situation, the tuft of vessels becomes
compressed, shrunk, and, in most cases, invisible.
Under the heading " Partial distribution of the oleo-albuminous exudation," Dr.
Gairdner describes, in the following terms, a peculiar pathological condition of the
kidney : — " I have already described the formation of granulations as dependent on
the accumulation of deposit in particular groups of tubules in the cortical substance.
In such cases, however, the affection is probably, at first, general; they are very dif-
ferent from the form now to be described, in which the deposit is quite limited in
extent, and isolated.
" There are occasionally met with, on removing the capsule from the surface of a
kidney, irregular patches, of a paler colour than the rest of the organ, sometimes a
little elevated, sometimes depressed below the general surface. Their boundary is
quite abrupt, and they are frequently surrounded by a well-marked rose-coloured
areola, extending more or less into the surrounding substance. On making a section
of these patches, they are found to penetrate into the cortical substance, and some-
times even a certain way into the pyramids. The vascular areola, when present,
extends round them in every direction, and is found, on examination, to consist of
GLANDS. 471
highly-injected Malpighian bodies and capillaries, with or without extravasation; the
colour of the patches varies from yellowish-gray to gamboge-yellow: their con-
sistence is generally firm. On microscopic examination, they present a large amount
of exudation, varying from the molecular to the large granular form. In some cases
the tubes may be seen filled with exudation ; in others they appear to be in great
part obliterated. In one case I found the Malpighian bodies quite free of exudation;
they preserved their usual arrangement, and were readily discoverable by a simple
lens on the surface of the section. The parts of the kidney not involved in the
deposit, generally present no abnormal appearance."
Lesions affecting cliiejly the Vascular System.
Variations in the vascular condition of the kidney may, and frequently do exist,
totally unconnected with organic change: thus, this organ, like all other vascular
structures, may be either in a hyperemic or anaemic state ; and these conditions may
affect either the entire vascular system, or they may be local only, or they may
involve respectively the venous or arterial vessels. The veins of the kidney are dis-
posed chiefly in two situations, viz : on its surface, and in the substance of the
pyramids, the cortical substance containing but few veins. On the surface the
larger vessels follow a somewhat stelliform arrangment, while the capillaries them-
selves form a mesh-work, the meshes describing small pentagonal or hexagonal
spaces, in each of which a single convolution of a tube is situated. The state of
these vessels is subject to much variation ; they may be in an anaemic condition, and
scarcely visible, or they may be gorged with blood ; in some instances this engorgement
is general, and in others it is confined to the stelliform vessels just referred to. These
conditions, as already observed, may be totally unconnected with disease; when,
however, there is great irregularity of injection, amounting to marbling of the sur-
face, and great increase in the size of the stellar vessels, these are generally
pathological, and result either from partial obliteration of the venous net-work, or of
the extrusion of the blood from it, through over-distention of the loops of tubuli
which form the intervening pale spaces.
" The engorgement of the capillaries and Malpighian tufts gives rise to two condi-
tions: first, a generally diffused heightened colour of the cortical substance; and
second, increase and greater distinctness of the vascular striae, running from the base
of the pyramids to the external surface. This latter species of injection often exists
to a great extent, without any corresponding injection of the rest of the kidney, and
in some instances the red points composing the striae are so much increased in size
as to form considerable petechiae (one line in diameter, or upwards), in which case
the petechiae usually extend to the surface, occupying the intervening spaces of the
venous polygons above mentioned. This appearance was supposed by Rayer to
occur from simple hypertrophy and vascular injection of the Malpighian bodies; but
Bowman,* who has shown that the Malpighian bodies do not exist on the surface of
the kidney, has also given a better explanation of such petechia?, which he holds to
arise from rupture of the Malpighian tuft, with extravasation of blood into the
surrounding tubes. He argues that the petechiae are of irregular form, and of much
larger size than the Malpighian bodies have ever been observed to acquire. He gives,
* Philosophical Transactions, 1842.
472 THE SOLIDS.
also, a figure representing the occurrence of a similar appearance, from artificial
injection, at the surface of the kidney. In this figure the loops or knuckles of the
tubuli are seen filled with injection, presenting themselves at the surface, and sur-
rounded by the venous net-work."
The correctness of this explanation cannot he douhted; and it is therefore evident
that the occurrence of these petechiae must be considered as invariably morbid.
The anajmic condition of the kidney, when the result of disease, is generally
accompanied by increase in the size of the tubes from contained secretion; and it is
the pressure of these on the surrounding vessels that occasions their empty condi-
tion, and, in some instances, even obliteration. The vessels of the Malpighian tufts
likewise become involved, and the Malpighian corpuscles themselves, thereby altered
inform, from being globular they become angular and compressed.
Under the heading, " Congestion followed by permanent obliteration of the
Capillaries," Dr. Gairdner has described a lesion of the kidney, which he has desig-
nated by the term " waxy degeneration?' in contra-distinction to the "fatty degeneration"
" The appearances most characteristic to the naked eye of this form of lesion, are
-those so admirably figured and described by Rayer as the second- form of his
' nephrite albumineuse.' The kidneys are generally increased in size, sometimes very
remarkably so. Their consistence varies: they are sometimes more flaccid than in
the natural condition, but always preserve considerable tenacity. The surface is
either quite smooth, or more or less depressed and furrowed. The venous vascu-
larity assumes, to a considerable extent, the stellate form; the polygons are mostly
absent; and the extreme irregularity and abruptness of distribution of the superficial
veins gives to the surface a variegated or 'marbled' appearance, which is quite
characteristic of this stage of the affection. (See Rayer, Plate, VI. figs. 2, 3. 5 ;
Bright, Plate II. fig. 1.) Occasionally, also, amid this unequal injection, there are to
be found scattered petechia?, indicating recent extravasations of blood into the tubes.
On section, the cortical substance has considerable volume, and presents a smooth,
glistening, almost semi-transparent appearance, which cannot be better distinguished
than by the term waxy. It may partake in a slighter degree of the variegated
character of the surface; more commonly it is of uniform appearance, and of a
yellowish or fawn-colour, sometimes verging into a pale flesh tint. The vascular
strise of the cortical substance are generally to be traced by a more or less distinct
injection, and a few injected Malpighian bodies, or petechia? of extravasation, are
sometimes dispersed through the section. (See Rayer, Plate X. fig. 3.) In other
cases, a little further advanced, both the striae and the Malpighian bodies are nearly
destitute of blood. (Rayer, Plate X. fig. 1 ; Bright, Plate II. fig. 1.) The pyramids
frequently retain their normal vascularity; sometimes, however, they are of a pale
colour, and their bases are indistinctly marked — a condition which indicates the
progress towards a further disorganization.
" When a kidney in this condition is carefully and minutely injected, the greater
proportion of the cortical substance remains impervious; the injection however, can
frequently be made to penetrate as far as the cortical stria?, and even to some of the
Malpighian bodies. (See Rayer, Plate X. fig. 2; Bright, Plate II. fig. 3.)
GLANDS. 473
" From these circumstances it is obvious, that the lesion above described consists
in an obliteration or obstruction of the capillary system of vessels throughout the
organ, and a partial obliteration of the veins on its surface. There is also every
probability that this condition is secondary to one in which there is a high degree of
congestion of the organ. The extravasations, the occasionally injected Malpighian
bodies, and the highly injected though partially distributed stellar veins, leave no
doubt that the state of congestion described as the first form of albuminous
nephritis by Raver, is really the antecedent of the present or second form.
" To any one who is familiar with the marbled and waxy kidney here described,
there can be no difficulty in recognising a further stage of the same lesion, in which
the organ is perfectly pale, both on the surface and on section, with the exception,
perhaps, of a very few stellated superficial veins. The kidney in this stage (the
transition to which seems to be represented in Rayer, Plate VI. fig. 4) is still heavy
and voluminous; it acquires additional firmness and elasticity, and assumes much of
the general appearance of a true non-vascular texture. It varies from a light yellow
to a fawn-colour, which extends to the pyramids, the bases of which become still
more confused and intermingled with the cortical substance than in the marbled
kidney. The capsule is frequently more firmly adherent to the external surface
than in health.
"From the pale and yellow appearance of the kidney in this stage, it is very apt to
be mistaken, even by a practised eye, for an extreme degree of the fatty degenera-
tion. A well-marked example, indeed, will hardly give rise to this error, if attention
be directed to the degree of firmness of the organ, the peculiar lustrous character of
the cut surface, and the entire absence of the opaque granulations of Bright, or of
that dull tint which distinguishes the excessive degrees of the fatty disease. The
appreciation of these characters is, however, more difficult where, as sometimes
happens, exudation is also present; and the distinction which has escaped the acute
observation of M. Rayer, has undoubtedly been overlooked by many other observers.
"The microscopic characters of this lesion are chiefly negative. There is not
unfrequently an entire absence of exudation ; indeed, in the most marked cases of
the lesion, I have seldom found even the slightest trace of any abnormal deposit.
Occasionally, however, there is a very minute quantity of fatty exudation In the tubes,
generally in very small granules, and scattered throughout the organ. The tubes
are either natural, or in the advanced stages pass into some of the states hereafter to
be described. The capillary vessels surrounding the tubes are not visible, and in
their place there is fibrous tissue, which in this form of lesion always appears some-
what exaggerated. The Malpighian bodies are also frequently seen in process of
obliteration, and surrounded by dense capsules of fibrous tissue. The epithelium is
frequently altered in character, but its changes follow no fixed rule.
"The absence or scantiness of exudation, taken in connexion with the extent of
degeneration appreciable by the naked eye, are amply sufficient characters to
distinguish this lesion from the extreme stages of the fatty disease."
474 THE SOLIDS
Lesions of the Tubes and Epithelium.
Some of these lesions have been already described under the head of exudation;
but there are others which are not less important than those formerly alluded to,
and which are very frequently found in connexion with them.
Imperfect Development of the Epithelium Cells and Nuclei- — The epithelium cells
and nuclei vary in size and characters within certain limits even in healthy kidneys;
the nuclei less so than the cells themselves; but in all kidneys, whether healthy or
diseased, the nuclei which are most closely adherent to the basement membrane are
less perfectly circular, and of considerably smaller size, than those lining the tubes
and surrounded by complete cell-walls.
Those acquainted with the normal anatomy of the kidney will be able to determine
the limits of variations in the epithelium and nuclei compatible with a state of health.
In very many pathological conditions of the organ, the nuclei occur in various
places almost wholly devoid of cell-walls. They may be more abundant or more
scanty than usual; and often appear in great profusion, huddled together in con-
fused masses, and mixed with shreds of membrane and amorphous molecular matter,
not soluble in acetic acid. This appearance of dtbris, which no doubt results from
disintegration of the cell-walls, most frequently occurs in kidneys which are abnor-
mally soft and large, and from the cut surface of which an unusually large quantity
of turbid whitish juice may be scraped. Such softened and altered kidneys occur
frequently in fever and other diseases.
A more unequivocal pathological change (often occurring along with the above) is
the small size and altered form of the nuclei throughout the organs, these not being
more than half the usual size, and always destitute of cell-walls. Sometimes they
float scattered and solitary in the field of the microscope; at other times, they
appear aggregated together either by two's or three's, or in much greater numbers,
the connecting medium being a transparent and'filmy substance, the nascent or
undeveloped cell-membrane which has separated from the basement membrane, along
with the half-developed or young nuclei above described. These aggregations of
young nuclei are sometimes mingled with the amorphous dtbris of effete epithelium, or
with granules and molecules of oleo-albuminous exudation, or of lithate of ammonia,
which communicate to them a dark and confused appearance: not unfrequently, also,
these masses, when freed from the tubes, retain more or less of their form, and
present so exactly the appearance of the casts of the tubuli seen by Franz Simon,
and many other observers, in the urine, as to leave no doubt of their identity with
these bodies.
Desquamation of the Epithelium. — The changes above described are generally
accompanied by an extremely rapid generation of nuclei, which are separated from
the basement membrane in an imperfect state, and earned away along with the urine,
in which they may be readily detected.
In some cases of desquamation of the epithelium, it is scarcely possible to recog-
nise any departure from the usual condition of the kidney, either with or without the
GLANDS. 475
assistance of the microscope. The degree of vascularity is very various in different
specimens, and the epithelium thrown off is so quickly resupplied, that there is no
very observable change in the microscopic condition of the tubules. In one very
intense case, in which ten pounds of very watery urine, loaded with an epithelial
sediment, were passed daily for some weeks before death, the kidneys were small,
flaccid, and bloodless ; many of the tubes were quite full of nuclei closely heaped
together; some of the nuclei were under-sized; the cells, when entire, were much
compressed and angular. In an another instance, where urine was passed in large
quantity and full of epithelial debris, during the last two months of life, the kidneys
were found in an opposite condition, viz : large and congested, and with a firmness
and smoothness of section like the first stage of the waxy degeneration formerly
described. In this case, the condition of the tubuli was in most parts quite natural ;
in some, however, there was extravasated blood, and in others the epithelium had
accumulated in abnormal quantity. In both these cases there was imperfect develop-
ment of the epithelium, but cases have occurred to me in which this character was
by no means wTell marked : the crowding of the tubes with nuclei, although frequently
found in the earlier stages of desquamation, is not invariably present; and the
tubes were even seen to be gorged with epithelium in a case where none had been
separated from the urine for weeks before death.
So long, therefore, as the epithelium is freely regenerated, the kidneys may present
a tolerably healthy appearance, even on minute examination : after prolonged disease,
however, further changes take place ; the epithelium becomes more sparingly gener-
ated, and is thrown off in the coherent masses above described, leaving the basement
membrane in portions bare, or with a few scattered oval nuclei, much smaller than
those cast off, adhering to its inner surface. In the microscopic examination of
organs in this condition, there are frequently seen films of such exceeding delicacy
and transparency as to be only visible by very careful management of the light : they
preserve the shape of the tubules, and contain no nuclei or structures of any kind.
Similar films are occasionally seen in the sediment of urine. They are probably
thrown off from the denuded basement membrane.
" Obliteration of the Tubes. — The basement membrane, which, with the few closely
adherent oval nuclei above described, is now the sole remaining structure of the
tubes, soon undergoes a change. It loses the cylindrical form proper to it in the
fresh and natural kidney, and becomes flattened by the pressure of the surrounding
parts. Its cavity is thus obliterated, and what was a tube assumes the appearance
of a transparent riband, dotted here and there with small oval nuclei, which, when
seen at the edges, appear to be enclosed between twTo layers of membrane. These
riband-shaped portions of membrane appear to present considerable tenacity and elas-
ticity ; by their greater density, and by the constant presence of the small oval nuclei
so often mentioned between their layers, they are in most cases readily distinguished
from the delicate films which have been referred to above. They are very various in
diameter, but are always inferior in this respect to the normal tubes; and they appear
to break up spontaneously into smaller portions, each of which contains from one to
six or more nuclei : these portions are of various sizes ; they are usually broadest in
the middle, and taper to a point at both ends. The smallest of them contain only a
476 THE SOLIDS.
single nucleus, and present an appearance in every respect like that of young- fibres
of areolar texture, or those fusiform cells, which have been called fibro-plastic. I
think it probable that the whole of the diseased basement membrane ultimately splits
up into fibres of this kind. While these changes are proceeding, the capillary vessels,
which have ceased to be subservient to secretion, are usually obliterated : the conse-
quence of this double obliteration of vessels and tubes is a considerable degree of
atrophy in the diseased parts ; and as the atrophy takes place at first chiefly in the
cortical substance, great irregularities of the surface generally supervene : thence
arises the appearance so well described and figured by Dr. Bright (Plate EI. fig. 2),
in which, from the atrophy of the cortical substance, the bases of the pyramids ' are
drawn towards the surface of the kidney.'
"When oleo-albuminous exudation supervenes on the above derangement of the
tubes, or when desquamation supervenes on the former (circumstances which I con-
ceive to be of very common occurrence), the exudation most commonly takes the
form of the granulations of Bright, which are deposited chiefly in the diseased tubes :
and the atrophy proceeding around these, they become salient, and the surface
generally irregular, giving rise to the tuberculated state of the surface so common in
all the later stages of the granulated kidney. (Bright, Plate III. fig. 1 ; Rayer,
Plate VII. fig. 6. Plate IX. fig. 8.) As the atrophy, however, proceeds, the granu-
lations are gradually absorbed ; and when the kidney has become extremely con-
tracted and irregular, they often in part disappear.
"The atrophied portions of the kidney are usually ex-sanguine, and of a tawney or
drab colour: they have considerable hardness and toughness. Examined microscopic-
ally, they appear to consist of fibres and fusiform cells in great abundance, and more or
less granular exudation, according to circumstances. According to Henle, Eichholtz,
Gluge, and others, these fibres are in great part new formations ; Johnson and Simon
consider them as nothing more than the compressed parenchyma of the gland, from
which all the other normal elements have disappeared. I look upon them as formed
in great part by the breaking up of the basement membrane of the tubes (as above
described), as well as from the parenchyma and obliterated capillaries. It is not
improbable, however, that in addition to these elements, some new fibrous tissue
is formed.
" The extreme stage of the atrophied kidney is nearly the same, whether exuda-
tion have existed or not.
"Microscopic Cyst-formation. — It occasionally happens, on examining the section
of a kidney with the microscope, that we see, scattered through some parts of the
section, a few small clear vesicles, of nearly circular or oval form : they are either of
a very pale straw-colour, or nearly colourless, and are perfectly clear and translucent,
with a very distinct shadowed margin, which causes them to stand out in bold relief
from the other textures composing the section. Their diameter is usually from one-
fortieth to one-fifteenth of a millimetre, but in this respect they vary considerably ;
sometimes they appear to lie in the tubular areolae, and at other times to be uncon-
nected with these. Very rarely they have appeared to contain a few granules ; most
commonly, even when there is granular exudation around them on every side, they
contain nothing but clear fluid. Their refractive power is not so great as that of
GLANDS. 477
oil, while it is much greater than that of the spherical cells of the tubes: hence their
distinct and characteristic shadowed outline.
" These bodies (which, however, have never appeared to me to present distinct
nuclei) are probably the same with the ' nucleated cells or vesicles' described by Mr.
Simon as resulting from the extravasation of the epithelial cells into the inter-tubular
tissue, and as progressively enlarging, so as to form the cysts visible to the naked
eye, which are so common in diseased kidneys. To these structures he attaches
great importance in the pathology of the kidney, conceiving them to be the invariable
result of the desquamative disease when of long standing; the kidney being, in Mr.
Simon's opinion, changed more or less into an aggregation of microscopic cysts,
which either undergo absorption, and lead to atrophy of the organ, or increase in
size, and monopolize its texture. Thus, according to Mr. Simon, the serous cysts so
common in the kidney result from an enormous development and hypertrophy of
extravasated epithelium cells, which assume the character of the vesicles he describes,
and acquire the power of increase and endogenous development.
" Whether the bodies described by me above, are the same with the vesicles of
Mr. Simon, I have some difficulty in determining : but they are the only objects I
have seen which correspond at all closely with his description; unless, indeed, it
were possible to suppose, as Dr. Johnson appears to hint, that he may have mistaken
the normal disposition of the tubuli for a cystic structure.
" However this may be, I am satisfied that the vesicles above described are excep-
tional productions, and by no means invariably connected, as Mr. Simon describes
his vesicles to be, with the progress of the desquamative degeneration. They are
seen in comparatively few cases : on referring to four, of which I have drawings or
memoranda, I find two to have been congested and waxy kidneys, with slight exuda-
tion; one to have been a soft and desquamating kidney, also with slight exudation;
and one a granular kidney with numerous cysts, from the size of a pea to that of a
hazel-nut. On the other hand, I have examined organs in every stage of desquama-
tive disease without finding these bodies, the production of which cannot therefore
be an essential step in the degeneration and atrophy of kidneys so affected.
" The origin and progress of these vesicles is very obscure. It is not improbable
that, as Mr. Simon asserts, they are transformed into the larger cysts visible to the
naked eye : though I confess that I have not been able to trace the intermediate steps
of their progress in a satisfactory manner. On the other hand, their origin from
extravasated epithelial cells seems exceedingly improbable ; indeed, I have already
stated, that I do not think the epithelium ever becomes extravasated. Moreover, the
vesicles in question have all the appearance of being formed within the tubes,
although they afterwards become separated from them.
" From the occasional appearances of alternate distention and constriction pre-
sented by the tubes when undergoing obliteration, I am induced to believe that cysts
may be formed by the occlusion and isolation of portions of tube which have not yet
lost their power of secretion. Whether the vesicles in question are formed in this
way, can only be determined by close and repeated observation ; and I have not been
able to obtain demonstrative evidence on this point.
" The larger cysts in the kidney present very strong evidence of being formed in
connexion with the secreting membrane. In one instance, I found their inner surface
478 THE SOLIDS.
to be lined at some points with tessellated epithelium, in the form of pentagonal or
hexagonal flattened cells, with circular nuclei; in another case, there were oval
nuclei without any distinct cells, and a large number of free oil globules of consider-
able size. The existence of oil in these cysts has also been observed by Dr. Johnson.
Other products of secretion are also occasionally found. On one occasion I found
several cysts in a kidney, otherwise healthy in appearance, which contained a turbid
ochrey-coloured liquid, presenting under the microscope numerous minute crystals
of uric acid. Mr. Simon mentions having found on two occasions xanthic oxyde in
considerable proportion. I have more than once observed them to contain blood hi
large quantity; and I have likewise found them full of a matter like stiff glue.
" The occurrence of cysts in kidneys presenting a generally healthy structure is so
frequent, as to lead to the idea that they must be in such cases the result of disease
which has been arrested before any considerable disorganization has taken place.
Many of the cases of partial atrophy of the kidneys figured by Rayer are probably
due to the rupture or obliteration of these cysts.
"Before leaving the subject of cyst-formation, I may state, that in one instance I
have observed the Malpighian capsules to be occupied by distinct cysts.*
" Dilatation and Thickening of the Tuhes. — This condition, although by no means
a very frequent one, is important, as being characteristic, so far as I have observed,
of the extreme stage of what I have called the ' waxy degeneration.' I have scarcely
ever seen it unaccompanied by entire obliteration of the vessels, and by enlargement
and increased density of the kidney. The organ has the dense resistant feeling of
fibro-cartilage, and both cortical and tubular portions have the light yellow colour,
and the appearances described above as those of the waxy degeneration in its last
stage. The striee of the pyramids appear to radiate indefinitely towards the surface,
and meet the cortical substance in digitations, instead of being marked off by a sharp
semi-circular line, as occurs in the healthy kidney. When examined with a simple
lens, or even the naked eye, the pyramidal stria) are seen to pursue an unusually
sinuous course: this is peculiarly the case where they pass into the cortical substance.
"Moreover, the pyramids are unusually broad at the bases; and the length of the
straggling digitations is sometimes so great, that I have measured fully an inch and
a half between the extreme end of the strke and the corresponding papilla. Never-
theless, the cortical substance is not usually diminished in quantity, being developed
to a great extent between the pyramids.
" This condition I have ascertained to proceed from dilatation and thickening of
the tubuli uriniferi throughout the organ. The dilated tubes are usually twisted and
varicose, as may be seen by inspecting a section of the pyramids with a low power.
When examined with a higher power, the section presents an appearance very similar
to some tumours (of the fibrous or fibro-cysted kinds), viz : a number of compressed
areolae, enclosed by fibrous tissue, and presenting an appearance of irregular con-
centric rings, of various distinctness, (an effect apparently due to the peculiar refrac-
* Obs. In one case of cystic disease of the kidneys which fell under the notice of
Mr. Quekett, the formation of the cysts evidently commenced in the corpora Mal-
pighiana beneath the capillary plexus. — A. H. H.
GLANDS. 479
tion of light by the thickened membrane.) The nuclei are obscured or invisible
owing to the thicknass of the intervening wall, but nevertheless exist in considerable
numbers. The Malpighian bodies and capillaries are usually obliterated. The kidney
nas in fact become, like the tumours whose structure it resembles, a true non-
vascular texture.
" The explanation of the peculiar extension of the pyramidal strise towards the
surface in these cases, is to be found in the fact that, even in the normal condition,
the convoluted, tubuli have a general disposition from the bases of the pyramids
towards the surface, in the direction of the strise of the cones. This is evident from
the facility with which the gland tears in that direction; although in the normal state
this disposition is masked by that of the vessels, which, passing in straight lines
through the cones, break into a complicated net-work of capillaries at the bases of
the pyramids. In the present lesinn, the vessels having disappeared, and the course
of tubes being strongly marked, their disposition towards the surface becomes mani-
fest, and the abrupt line of demarcation between the cortical and pyramidal substance,
caused by the presence of the vessels, is obliterated."
CONCLUSION.
With the view of enabling the reader to place the foregoing observations in
relation with the descriptions found in systematic pathological works, Dr. Gairdner
subjoins the following short remarks on the principal physical characters usually
ascribed to diseased kidneys :
" Increase of Size and Weight : Hypertrophy. — Enlargement of the kidney occurs
chiefly in consequence of three conditions: — 1st, from sanguineous engorgement; 2d,
from distention of the tubes by secretion or exudation; 3d, from permanent dilatation
and thickening of the tubes. Of all these causes, the second is by far the most
common. The last is characteristic of the waxy degeneration formerly described.
"The quantity of liquid in the tubes is, at all times, subject to so much variation,
that it is difficult to say what amount of increase of weight may be thereby occasioned
without the existence of any positively morbid condition. It is not very uncommon
to find kidneys, otherwise not differing from the healthy standard, about double the
usual weight, or between seven and eight ounces each. I have more than once found
them to weigh nine ounces each, with very slight marks of disease. When the weight
much exceeds this, it is probable it arises from the rare combination of vascular and
tubular engorgement.
" In kidneys containing oleo-albuminous exudation, the greatest increase of size is
attained, when the exudation is universal, and unaccompanied by desquamation.
"Cystic degeneration of the kidneys, dilatation of the pelvis and ureters (Hydro-
ntphrose, Rayer), &c, also give rise to great increase of size and weight.
"Diminution of Size and Weight: Atrophy.— This condition sometimes occurs to
a certain extent, in emaciated subjects, without any disorganization, owing to the
480 THE SOLIDS.
diminished activity of secretion. More frequently, however, it is the result of sepa-
ration of the epithelium, followed by contraction and obliteration of the tubular
structure.
" Atrophy, from this cause, is liable to supervene in all other varieties of renal
lesion, except the waxy degeneration, which appears to lead to a permanently hyper-
trophied condition of the organ. In kidneys enlarged from exudation, the occurrence
of desquamation and its consequences is frequent ; and the diminution of size in
such cases is often not followed by a return to the natural condition, but by perma-
nent atrophy.
" The course of all disorganizing diseases of the kidney is to produce first, enlarge-
ment, and then contraction of the organ. In the extreme stages of the atrophy
which results from exudation, exudation is often nearly absent. When exudation,
therefore, even in very sparing quantity, accompanies a contracted condition of the
kidney, there is a probability that it has been abundant at some former period.
" Irregularities of Surface : Tuberculated and Granulated Kidneys. — The smooth-
ness of the surface in the kidney is destroyed either by unequal dilatation or unequal
contraction of the tubili of the cortical substance. The former takes place in the
waxy degeneration ; the latter, in the desquamative processes.
" The most frequent irregularities of surface are formed in connexion with the
granulations of Bright. These are invariably formed when exudation is deposited
in kidneys tending to the desquamative lesion ; and, as this runs its usual course, the
granulations become prominent from the destruction of the tubes around them. An
extreme degree of the irregularities thus produced, constitutes the tuberculated
kidney.
" The puckering and partial atrophy occasionally seen in kidneys, otherwise not
morbid, or comparatively slightly diseased, are probably, in many instances, the
result of the obliteration of cysts.
"The more remarkable changes in colour and consistence are described very fully
in many parts of the preceding memoir."
On reviewing the whole of the preceding observations, Dr. Gairdner is induced to
regard the following conclusions as especially important in relation to the pathology
of renal diseases:
"1. By far the greater part of the pathological lesions of the kidney arise from, or
are connected with, the exudation of oleo-albuminous granules into the interior of
the tubes and epithelial cells.
" 2. The oleo-albuminous exudation is, probably, often preceded, and, certainly,
occasionally accompanied, by vascular congestion ; but when the quantity of exuda-
tion is considerable, more or less complete depletion of the vascular system invariably
occurs. This is a secondary result of the obstruction of the lubuli uriniferi.
" 3. The oleo-albuminous exudation occurs in two chief forms, viz : first, universal
infiltration of the tubes throughout the organ ; and, second, infiltration of peculiar
GLANDS. 481
sets of tubules : the rest remaining free, or nearly so. In the latter mode arise the
granulations of Bright.
" 4. There is no essential anatomical difference between the exudations in the kid-
ney, which are the result of chronic processes, and those which have been considered
as the result of inflammation.
" 5. The capillary vessels of the kidney are subject to spontaneous obliteration
(unaccompanied, in the first instance, by any visible lesion of the tubes), giving rise
to the peculiar affection which I have called the waxy degeneration. This oblitera-
tion of the vessels is probably, in all cases, preceded by a stage of congestion.
" 6. The consequence of the waxy degeneration is thickening and varicose dilata-
tion of the tubuli throughout the organ.
" 7. The tubes of the kidney are subject to contraction and obliteration, in conse-
quence of the desquamation of their epithelium; a condition resulting in atrophy, and
complete disorganization of the organ.
" 8. The desquamation of the epithelium occurs very frequently in all the other dis-
eased conditions of the kidney. When sufficiently long-continued and extensive, it
produces contraction, and this indifferently, whether exudation be present or not. It
is sometimes accompanied by vascular congestion in every stage of its progress.
" 9. The earlier stages of the exudations can only be discovered by means of the
microscope. The progress of the waxy degeneration, on the contrary, is best traced
by the unaided eye. The desquamation of the epithelium is only to be discovered
with certainty by means of the microscope, and is particularly apt to escape attention,
under all circumstances, if the kidney only, and not the urine, be looked to. It results
that careful investigation, both by the microscope and the naked eye, both of the
kidney after death and the urine during life, are indispensable, to enable the patholo-
gist to determine with exactitude the presence or absence of disease."
I have been induced to dwell thus largely on the microscopic
pathology" of the kidney: first, on account of the great importance
and interest attached to the lesions of that organ ; secondly, from the
great number of interesting facts which the microscope has already
brought to light in reference to its pathology ; and, thirdly, in the
hope of inducing other observers to follow out more completely the
inquiry which has already led to such successful and striking results.
31
482 THE SOLIDS,
KIDNEY.
[The anatomy of the kidney may be in part studied by dissection of
recent specimens under water. The structure, however, is more readily
made out after injection, and this is best performed after removal from the
body. An injection by either set of vessels almost always passes into the
others. Hence an injection by the artery frequently fills partially the
tubule uriniferi and the veins. It will be exceedingly difficult to limit the
injection to the terminations of the vessel injected ; many trials, however,
will enable one to judge how much force is necessary to fill only the set of
vessels desired.
When three colours can be successfully employed, the best arrangement
will be found to be — red or blue for the arteries, yellow for the veins, and
white for the urinary tubes. When it is required to fill the three sets of
vessels with one injection, the artery must be first injected, and the urinif-
erous tubes farther filled from the ureter. It may be here stated, that for
practise in making fine injections, the kidneys of sheep, pigs, &c, will be
found the organs most suitable for that purpose. They are easily obtained,
are sufficiently difficult to inject, and do not require a very large amount
of material.
Injections of the kidneys are best preserved in Canada balsam without
heat, after being cut in slices, and dried. Cells may be used or not,
according to the thickness of the specimen.
Plate LXXV. fig. 5, Malpighian bodies and their relation to the urinif-
erous tubes,
fig. 6, The same enlarged, as in the first stage of Bright's
disease.
Plate LXXVI. fig. 1, Enlarged veins of kidney.
" fig. 2, The same ; another view.
" fig. 3, Stellated condition of veins.
" fig. 4, Granulation on the surface of the kidney.
" fig. 5, A tube much dilated.]
GLANDS. 483
The testis, the last of the tubular glands in the human subject,
agrees more closely in structure with the sudoriferous and ceruminous
glands than with the kidney; there being this in common between the
three first mentioned, viz : that the tubes, of which they are principally
constituted, are convoluted, and are not enclosed in a dense frame-
work of fibro-elastic tissue, as is the case with those of the kidney.
The testis, is invested by a tunic of white fibrous tissue; this sends
down, into the substance of the gland, numerous dissepiments, which
divide the tubes of which it is composed into parcels, each of which
may be called a lobe.
The tubes of the testes are remarkable for their large size, great
tortuosity, and exceeding and ready extensibility. (See Plate LX.
figs. 1.4.)
When viewed as opaque objects, the tubes appear of a delicate
and semi-transparent whiteness; and, when seen by transmitted light,
they are almost black; this arises from the fact of the interception
of the luminous rays by the cells contained within the tubes.
The membrane of the tubes is totally distinct from that of most
other tubular glands; it is very thick and fibrous, being constituted
of a well-marked form of nucleated fibro-elastic tissue. (See Plate
LX.^.4.)
The constitution of the tubes of elastic tissue explains satisfactorily
their ready extensibility and variable diameter; this variation, in
specimens prepared for microscopic examination, is very obvious, and
arises from the displacement of the contained cells, occasioned by
unequal external pressure; where these cells are accumulated in the
greatest number, there the tubes are thickest ; and where there are
but few cells, or even where the tubes are destitute of cells, they are
thinnest, and frequently even entirely collapsed.
These facts show that the tubes are highly expansive; and there is
no doubt that their diameter varies, during life, in accordance with
the amount of seminal fluid contained within the testis; this expansive
property being especially designed to allow of the accumulation of
that fluid within the semeniferous organ.
The tubes of the testis contain a vast number of granular cells of
various sizes (see Plate LX. jig. 4), some being several times larger
than others, especially in the testis of the adult. Most of these cells
contain but a single nucleus ; in others, however, and these the larger
484 THE S0LID3.
cells, there are as many as from two to seven, or even more, distinct
nuclei. (See Plate XVI. fig. 1.)
In the testes of a child, the granular cells present great uniformity
of size, and contain, for the most part, but a single nucleus. These
cells, as in other tubular glands, form a regular epithelium on the walls
of the tubes, the central channel being free ; this arrangement is very
evident in the tubes of immature testes ; but far less so in those of
the adult organ; the manipulation to which the latter are subject, when
being prepared for microscopical observation, readily displacing the
cells.
It is in these cells, according to the observations of numerous
observers, that the spermatozoa are developed. For further particu-
lars on the development of the spermatic animalcules, see the article
"Semen"
The tubes of the testes are loosely bound together by bands of
fibrous tissue; it is this tissue which contains the tortuous blood-
vessels with which this organ is so copiously supplied.
That the tubes are not furnished with a distinct external envelope,
like those belonging to the kidney, is proved by the fact that they
admit readily of being separated from each other, as also of being
drawn out to a great length : this last circumstance shows the extent
to which the tubes are convoluted, the few anastomoses which take
place between them, and their extraordinary elasticity.
VASCULAK GLANDS,
The vascular glands all agree with each other in the abscence of
excretory ducts or channels for the discharge of their secretion, a
deficiency which involves as a necessary consequence the reception
of the secreted fluids by the blood-vessels.
From the differences in the size and structure of these several glands,
it is very doubtful whether any other resemblance besides that just
pointed but exists between them, and it is most probable that each has
a separate purpose to fulfil in the animal economy.
THYMUS.
The thymus, although usually spoken of and described as a single
organ, is in reality double, and consists of two distinct glands united
to each other in the middle line by cellular tissue only.
Each separate adult thymus is constituted of numerous, probably
GLANDS. 485
some hundred follicles, which vary in size from a pin's head to, in
some cases, that of a pea, and the walls of which are made up of
mixed fibrous tissue.
These follicles are usually more or less rounded, but sometimes
polygonal in shape from pressure; they are loosely held together by
fibrous tissue, and by the blood-vessels which supply them ; they each
contain in their interior a cavity which is more or less filled with a
milky fluid. (See Plate LXI. fig. 8.)
Several of these follicles open into each other and into a common
receptacle or "pouch," and this last again opens into the internal
cavity of the gland, the face of which is thickly studded with similar
openings.
On its exterior each follicle may be seen, even without injection, to
be invested with a very beautiful plexus of blood-vessels, represented
in Plate LXI. fig. 8.
When unravelled by the removal of the inter-lobular cellular tissue,
the whole gland is seen to consist of a straight tube, with the follicles
arranged around it in a spiral manner.
The central cavity, " reservoir of thymus," is lined by a delicate
mucous membrane, which is raised into ridges by a layer of ligament-
ous bands situate beneath it; these proceed in various directions, and
encircle the apertures of the pouches : their use is to keep the lobules
together, and to prevent the injurious distention of the cavity.
The whole organ is enclosed in a dense capsule of fibrous tissue,
the blood-vessels contained in which are remarkable for their disposi-
tion in three's, an arrangement which is not uncommon in the capsular
investments of glands. (See Plate LXI. fig. 7.)
The "milky fluid" contained in the follicles and reservoir is made
up, to a great extent, of an immense number of granular nuclei, as
well as numerous cells of large size, which do not appear hitherto
to have been either described or figured in a satisfactory manner, and
which are probably to be regarded in the light of parent cells. (See
Plate LXI. fig. 10.)
Many of these cells contain several granular nuclei, each of which
is surrounded by one or more concentric lamellae ; they thus resemble
the cartilage cells found in the inter- vertebral substance, and also
certain species of Microcystis, a genus of Fresh- water Algae.
Mr. Simon, in his "Prize Essay," makes the following observations
on the above-described cells : — " In specimens taken from animals past
that period of life when the thymus is most active, I have found cells
486 THE SOLIDS.
in which these dotted corpuscles occupied the relation of nuclei. The
cells are at first little larger than the corpuscles themselves, and contain
a perfectly pellucid material; but as they grow, their contents become
molecular, and they develope themselves into perfect fat cells, which
lie in the cavities of the glands, and in some instances completely
fill them. During the period in which these cells are being developed,
the application of acetic acid to the preparation as it lies under the
microscope shows them to have great affinity to embryonic cells; for
the acid dissolves the cell-membrane completely away, and leaves the
nucleus of the cell (the dotted corpuscle) unaffected by its action."
Lining each follicle, Mr. Simon has detected a delicate and homo-
geneous structure, which he has termed the " limitary membrane :"
this structure is identical with the basement membrane of Bowman,
and is probably common to all glands, especially the follicular ones.
Mr. Simon has likewise described a lobular arrangement of the fol-
licles. The structure of the gland resolves itself, he says, "into
masses ranged round an axis. Each mass constitutes a sort of cone
of glandular substance, its apex pointing to the axis or mesial line of
the gland; its base directed to the surface, where it presents innumer-
able vesicles; while its intermediate part contains those successive
branchings of the follicle which terminate superficially in the vesicu-
lar form."
THYROID GLAND.
The anatomy of this gland is best studied in a specimen which has
undergone a slight enlargement of its several parts; a portion of such
a gland, when viewed, with the inch object-glass, bears so close a
resemblance to a mass of fat, that, except by a practised miscroscopist,
it would be impossible to distinguish it therefrom with such a low
power; even when viewed with the half-inch, the illusion would
scarcely be dispelled, and it is only on the application of the quarter-
inch glass, that misgivings would begin to be entertained in reference
to its identity with fat.
The resemblance borne by a portion of thyroid gland thus slightly
enlarged by disease to a mass of fat, arises from the form of the ves-
icles or closed cells of which the gland is composed, and from the
manner in which they reflect the light, the centre of each vesicle
being clear and bright, and the circumference dark and almost black;
here, however, the resemblance ceases, as the thyroid vesicles are
most satisfactorily distinguished from fat globules by their larger size,
the fibrous texture of their parietes, and the nature of their contents.
GLANDS. 487
Such is the general character and appearance of a portion of
thyroid examined microscopically; the entire gland, however, consists
of two lobes, which are placed one on each side of the trachea, and
which are connected with each other by a narrow slip, or isthmus of
the gland, and these lobes are further divisible into numerous lobules,
many hundreds to each lobe. Now, it is these lobules which, so far
as the descriptions hitherto given of this gland are to be understood,
have been regarded and described as the membranous cavities of
the thyroid (see Plate LXI. fig. 1), the true and ultimate cellular
structure being in general overlooked.
Thus the lobules are further divisible, each into many small
cavities, the ultimate divisions of which the gland is susceptible. (See
Plate LXI. figs. 2, 3, 4, 5.) These in the slightly enlarged gland
are circular, and comparable to fat vesicles (see Plate LXI. figs. 2,
3) ; but in the gland in its normal state, they are compressed and
angular, being also very liable to be altogether overlooked, their size
and form being indicated only by certain light-coloured spaces
traversing the lobule. (See Plate LXI. fig. 5.)
Over the surface of each lobule, the blood-vessels form a plexus,
from which branches proceed inwards, encircling the vesicles much
in the same way as the blood-vessels do the fat corpuscles. (See
Plate LXI. fig. 1.)
The cavity of each vesicle is perfectly distinct, and does not com-
municate with that of any other of the vesicles by which it is
surrounded: the fibrous tissue, however, of which its walls are so
evidently composed (Plate LXI. fig. 4), does communicate with and
run into that of the neighbouring vesicles, at certain points, however,
only. These fibres may frequently be traced from the wall of one
cell into that of another; and it is this fibrous union of the vesicles
which renders it impossible completely to isolate any one of the cells,
and accounts for the fact, that when the vesicles are broken up with
needles, they are entirely reduced to fibrous tissue.
The contents of the vesicles consist of a fluid, containing numerous
granular nuclei of a rounded or oval form, as well as of a few perfect
cells, two or three times larger than the nuclei, and the granules
contained in which are very large, presentingan oily aspect; between
these two extremes of size, other cells intermediate are met with: the
larger are evidently parent cells. (See Plate LXI. figs. 9 and 4.)
The fluid of the vesicles contains a good deal of oil, which, when
the gland is slightly decomposed, is apt to collect in them in the form
of one or two lame circular discs.
488 THE SOLIDS.
The increase in the size of the gland in goitre is due to an increased
development of the vesicles and of their contents.
It is evident that each vesicle contains all the elements of the gland,
and that the entire organ is made up of an assemblage of many thou-
sands of such vesicles or glands. (See Plate LXI. fig. 2.)
SUPRA-RENAL CAPSULES.
The supra-renal capsule bears some resemblance in structure to the
kidney, being divisible like it into a cortical and medullary substance.
It is made up of numerous simple and cylindrical tubes, closed at
both ends, and formed of structureless basement membrane; these
tubes are disposed in a vertical manner, one extremity forming the
surface of the organ, and the other extending in an opposite direction,
as far as the inner cavities or lacunae situated in the centre of each
supra-renal capsule. (See Plate LX.ll. Jig. 3 a.)
These tubes enclose elements of three kinds; first, innumerable
circular particles or molecules, which reflect the light strongly, and
which are of an oily nature; of these the greater part is free in the
tubes, but a lesser proportion is enclosed in certain of the cells which
are met with in the tubes ; second, granular nuclei in large quantities ;
and, third, parent cells of considerable size, containing each several
nuclei intermingled with, and in part very frequently obscured by a
considerable number of the bright molecules previously referred to.
These parent cells do not appear to have been hitherto characterized
with any degree of precision. (See Plate LXII. fig. 3 b.)
The differences between the cortical and medullary portions of the
supra-renal capsule, depend principally upon the irregular disposition
of the tubes in the latter, the plexiform arrangement of the vessels,
and on the presence of numerous parent cells containing more or less
of colouring matter in their interior. It is these cells which impart
to sections of the gland the dotted appearance so commonly observed
in its medullary portion. (See Plate LXII. fig. 3.)
The vascular distribution in the supra-renal is very simple. On
the surface of the organ we have a very beautiful plexus of capillaries,
the pentagonal and hexagonal meshes of which lie in the intervals
between the extremities of the tubes ; in the tubular part the vessels,
both veins and arteries run, in straight lines between the tubules,
terminating, on the one hand, in the plexus on the surface, and, on
the other, in the central plexus. (See Plate LXII. figs. 1. 5.)
The supra-renal is an organ which varies greatly in different sub-
GLANDS. 489
jects; in some the proportion of granules is much greater than in
others ; in others again, the central lacunae are occupied with a
whitish-looking substance, which, on examination, is found to consist
of granular nuclei arranged in irregular masses, but in which some-
times we can detect a tubular disposition: in these cases we encounter
from without inwards, three substances ; cortical, medullary, and then
lastly, the central substance just described.
The capsule of the supra- renal is often laden with fat, which totally
. obscures the plexus on the surface of the organ.
The parent cells, when filled with oily molecules, bear a close'
resemblance to the cells of a sebaceous gland, between which and the
supra-renal capsule one would hence be disposed to suspect a degree
of affinity.
SPLEEN.
The spleen consists of a fibro-elastic capsule which sends down
from its inner surface septa, which penetrate the organ in all direc-
tions, and divide it into compartments; of an immense assemblage of
blood-vessels which compose its chief substance, and which impart to
it the character and appearance of an erectile tissue ; and, thirdly and
lastly, of a small quantity of secreting structure, consisting of nuclei
only, and which appears to lie in the intervals between the blood-
vessels.* (See Plate LXII. fig. 2.)
The above comprehends all that can be readily made out of structure
in the spleen : the examination, however, of this organ is by no means
satisfactory or easy on account of the impossibility of fully injecting
it, a difficulty which arises from causes but imperfectly understood.
Dr. Julian Evans, however, describes a very elaborate structure
and arrangement of the tissues in the spleen, as will be seen from the
perusal of the following abstract of his paper, taken from the third
edition of Carpenter's "Principles of Human Physiology:"
" According to the account of Dr. Julian Evans.f whose researches
appear to have been more successful than those of any other anato-
mist, the spleen essentially consists of a fibrous membrane, which
constitutes its exterior envelope, and which sends prolongations in all
directions across its interior, so as to divide it into a number of minute
cavities or lacunas of irregular form. These splenic lacuna com-
municate freely with each other, and with the splenic vein ; and they
are lined by a continuation of the lining membrane of the latter,
*See Med. Chir. Rev. No. X. p. 28. \ Lancet, April 6th, 1844.
490 THE SOLIDS.
which is so reflected upon itself as to leave oval or circular foramina
by which each lacuna opens into others, or into the splenic vein.
The lacunae, whos'e usual diameter is estimated by Dr. E. at from halt
to one-third of a line, are generally traversed by filaments of elastic
tissue, imbedded in which a small artery and vein may be frequently
observed; over these filaments, the lining membrane is reflected in
folds; and, in this manner, each lacuna is incompletely divided into
two or more smaller compartments. There is no direct communi-
cation between the splenic artery and the interior of the lacunas ; but
its branches are distributed through the inter-cellular parenchyma
(which will be presently described) ; and the small veins which collect
the blood from the capillaries of the organ convey it into these cavities,
from which it is conveyed away by the splenic vein. The lacunae
may be readily injected from the splenic vein with either air or liquid,
provided they are not filled with coagulated blood ; and they are so
distensible, that the organ may be made to dilate to many times its
original size with very little force. This is especially the case in the
spleen of the Herbivora; for the spleen of a sheep weighing four
ounces, may be easily made to contain thirty ounces of water.
That of man, however, is less capable of this kind of enlargement.
According to Dr. Evans, the lacunae of the spleen never contain any
thing but blood : and he notices that a frequent condition of the human
spleen after death, which is sometimes described as a morbid appear-
ance, consists in the filling of the lacunae with firmly coagulated blood,
which gives a granular appearance to the organ.
"The partitions between the lacunae are formed, not only by the
membranes already mentioned, but by the peculiar parenchyma of the
spleen ; which constitutes a larger part of the organ in man, than in
the Herbivorous Mammalia. It presents a half-fluid appearance to the
eye ; but when an attempt is made to tear it, considerable resistance
is experienced, in consequence of its being intersected by what appear
to be minute fibres. When a small portion of it is pressed, a liquid is
separated: which is that commonly known as the Liquor Lienis, or
splenic blood; which is usually described (but erroneously, according
to Dr. E.) as filling the lacunae of the spleen. This liquid, when diluted
with serum, and examined under the microscope, is found to contain
two kinds of corpuscles — one sort being apparently identical with
ordinary blood corpuscles, and the other with the globules character-
istic of the lymph, and abundant in the lymphatic glands. The
remaining fibrous substance consists entirely of capillary blood-vessels
GLANDS. 491
and lymphatics, with minute corpuscles, much smaller than blood
corpuscles, varying in size from about 1 -6000th to 1 -7000th of an
inch, of spherical form, and usually corrugated on the surface. These
lie in great numbers in the meshes of the sanguiferous capillaries;
and the minute lymphatics are described by Dr. E. as connected with
the splenic corpuscles, and apparently arising from them. Lying in
the midst of the parenchyma, are found a large number of bodies, of
about a third of a line in diameter, which are evidently in close con-
nexion with the vascular system; these have been long known as the
Malpighian bodies of the spleen, after the name of their discoverer ;
but since his time, their existence has been denied, or other appear-
ances have been mistaken for them.
"According to Dr. E., they in all respects resemble the mesenteric,
or lymphatic glands in miniature, consisting as they do of convoluted
masses of blood-vessels and lymphatics, united together by elastic
tissue, so as to possess considerable firmness: and they further cor-
respond with them in this — that the lymph they contain, which was
quite transparent in their afferent lymphatics, now becomes somewhat
milky, from containing a large number of lymph globules."
Dr. Handfield Jones has noticed the occurrence of certain peculiar
corpuscles in the spleen of various animals, including that of fishes,
mammals, and man; these corpuscles he describes as follows:*
"In the spleens of various animals there may often be seen a number
of minute corpuscles of a yellow colour, varying from a dark to a pale
hue; they occur sometimes singly, but mostly in groups, which I have
sometimes thought were aggregated, especially along the larger blood
canals. These groups are made up of corpuscles of very various
size; they do not appear to have any special connexion with the
surrounding substance, which occasionally, however, has a decided
yellow tinge. ■
"In the animal series, I have found these corpuscles most highly
developed in fishes. In the human subject, they are rarely to be
found. I have, however, observed them distinctly in six instances, in
one of which they were very large and numerous. In most of the
cases in which they were found, there had been considerable inter-
ruption to the respiratory process. The spleen was generally much
enlarged, soft, and of rather a pale colour, quite an opposite condition
to that often observed in cases of 'Bright's Disease,' where the organ
* Medical Gazette, 1847, p. 141.
492 THE SOLIDS.
is found small and contracted: in such spleens I have never found
any of the yellow corpuscles."
For a description to the Pineal and Pituitary glands, placed in the
classification under the heading "Vascular Glands," the reader is
referred to the Appendix.
ABSORBENT GLANDS.
The absorbent system of vessels is divisible into lacteals and lym-
phatics, the glands attached to the former being called mesenteric,
and those to the latter, lymphatic glands.
The lacteal absorbents commence in a plexiform manner in the
villi of the small intestines, while the lymphatic absorbents originate
all over the body, in the same manner, in each of the several tissues
and organs of which it is composed : they are minute, delicate, and
transparent vessels, remarkable for their uniformity of size, a knotted
appearance due to the presence of numerous valves, the dichotomous
divisions which occur in their course, and their separation into several
branches immediately before entering a gland.*
In the mesentery, the lacteals become variously coiled and knotted,
these aggregations of coils, together with fibrous tissue and blood-
vessels, forming the mesenteric glands; the lymphatic glands have a
similar structure and origin, being placed in certain determinate
regions of the human body.
The lymphatics 'which enter a gland, or the afferent lymphatics,
vary in number from two to six ; they divide at a short distance from
the gland into several smaller vessels, and enter it by one of the flat-
tened surfaces: while those which leave it, or the efferent lymphatics,
escape from the gland on the opposite, but not unfrequently on the
same surface; they also consist, at their junction with the gland, of
several small vessels, which unite after a course of a few lines, and
form from one to three trunks, often twice as large as the afferent
lymphatics.
The afferent lacteals and lymphatics, as they enter the gland,
become somewhat dilated; and the epithelium, in place of forming a
single layer of flattened cells firmly adherent to the walls of the tubes,
consists of several layers of rounded and glandular cells, which are
very readily displaced.
These cells are doubtless more or less concerned in the elaboration
fSee the Article "Lymphatic System," by Mr. Lane, in the Cyclopaedia of Anatomy
and Physiology.
GLANDS. 493
of the fibrin of the chyle ; and there is much reason to believe that
from time to time the more mature cells become detached from the walls
of the lacteals, and are conveyed along with the chyle into the blood,
where they become the white or granular corpuscles of that fluid.
Such is a very brief outline of the minute anatomy of the mesen-
teric and lymphatic glands.
This is probably the most fit place to introduce a few remarks on
the structure of the villi themselves, the chief agents in the absorp-
tion of the chyme, and the parts in which the lacteals themselves
take their origin.
The Villi of the Intestines.
The villi exist in the whole extent of the small intestines, but it is in
the lower part of the duodenum and the whole of the jejunum that
they are best developed, and the lacteals most readily detected.
Several distinct structures have to be noticed and described enter-
ing into the constitution of each villus: these are the epithelium
resting upon the outer surface of the villus, the basement membrane,
the intra- villous nuclear contents, the fatty intra-villous contents, the
blood-vessels of the villus and its lacteals ; these several parts will be
described in the order of their enumeration.
The epithelium investing the villi (see Plate LII. fig. 1), is of the
conoidal variety, already fully described and figured. It not merely
clothes the villi from base to summit; but also the inter-spaces
between them, as well as the numerous follicles of Lieberkiihn, situated
in the whole length of the small intestines.
According to the observations of Professor Goodsir, this epithelium
is shed on each recurrence of the process of chymefication, the cells
first absorbing the partially elaborated chyme, effecting a further
elaboration of it, and finally becoming ruptured and dissolved, set free
the fluid absorbed, at the same time adding their own substance to
augment its amount and nutritive qualities.
The accuracy of this view is in the main admitted by most observ-
ers; Professor Weber and Dr. Jones, however, do not consider that
the shedding of the epithelium is necessary to enable the villi to per-
form their function'; and the latter observer makes the following
remarks on this point : " I have certainly seen the villi clad with their
epithelium when the lacteals have seemed to be every where filled
with chyle : however, I think there can be little doubt that, when the
absorbing process is most actively performed, the villus does throw
494 THE SOLIDS.
off its protecting covering; certainly, this is the case in a great
number of instances."*
The basement membrane of the villi is a continuation of that of
the general surface of the mucous membrane, and is, as far as has
yet been ascertained, perfectly structureless.
The granular, or, more correctly speaking, the nuclear contents of
the villi have been noticed by several observers. (See Plate LI I. Jigs.
1, 2). Dr. Jones, however, in the communication already referred
to, has pointed out the fact that the nuclear and granular contents of
one villus are continuous with those of another, and that the granules
and nuclei form a continuous stratum lying beneath the basement
membrane, extending not merely from villus to villus, but also
throughout the large intestines, where it is very easily seen in the
spaces between the follicles.
Professor Goodsir has described these granular nuclei, as enlarging
during the process of absorption, and as forming a number of enlarged
and very evident cells at the apex of the villus. These supposed
cells, however, are nothing more than oil drops, usually of a brown
colour, and of various sizes. (See Plate LII. jig. 2.) At this con-
clusion I arrived many months since, and gave a figure of these oil
drops in the villi in the 13th Part of the Microscopic Anatomy, pub-
lished in April, 1848; and I am glad that Dr. Jones entertains a
similar opinion of their nature. I may at the same time remark, that
the cells delineated in the original ^figure given by Professor Goodsir,
have all the characters of oil drops, being round, smooth, and reflect-
ing the light strongly.
The use of these oil drops in the villi is by no means evident; they
are formed, in all probability, by the cohesion of the smaller oily
granules which are scattered throughout the villi during the process
of absorption, and which contribute so greatly to their opacity; in
the end, they are most probably absorbed by the lacteals.
Notwithstanding, however, the non-existence of the peculiar cells
described by Professor Goodsir, the leading idea of that observer of
the elaboration of the chyme within the villus is still correct, the
agents in this work being the nuclei already described.
The presence of these nuclei throughout the whole length of the
villus seems to point to the inference that it is not the apex only
which absorbs.
Each villus is copiously supplied with blood-vessels; an artery
* Medical Gazette, Nov. 17th, 1848.
GLANDS. 495
ascends one side of the villus, a vein descends along the opposite side,
and between these two principal vessels a very complicated and beau-
tiful plexus of capillaries is extended. (See Plate LI. figs. 3, 4, 5.)
The lacteals are described as originating in the villi in a plexiform
manner.
In the rabbit I have observed a very curious construction of the
villi, their surfaces being studded with numerous mucous follicles;
the portion of intestine exhibiting these characters was most probably
taken from near the junction of the large and small intestines; and 1
have little doubt but that the villi of the human intestine, in a corres-
ponding position, would exhibit the same combination of the struct-
ural peculiarities of both small and large intestines.
The anatomical characters of the mucous membrane of the stom-
ach, and large intestines, have already been described. (See page
339. et seq.)
496 THE SOLIDS,
VILLI OP INTESTINES:
[The villi of the intestines can only be examined satisfactorily after injection,
and the removal of the epithelium. They may be seen, but not so well, in
the recent intestine, after the epithelium and mucus have been well washed
off, on examination under water with a low power. In the fowl and dog, as
in many other animals, the villi are longer than in the human subject. The
intestines may be injected with the other chylopoietic viscera from the vena
portee, or they may be injected alone from the superior and inferior mesen-
teric vein, or any portion of the intestinal canal may be isolated by applying
ligatures above and below the portion to be injected, containing the intestine
and mesentery, and the pipe of the syringe then placed in the largest mesen-
teric vein discoverable in the isolated portion.
After the injection has set, the intestine must be placed in water, to allow
the epithelium to become detached, and the mucus removed. It will be
sometimes necessary to wash the internal coat of the intestine with water
from a syringe. These injections are best preserved in cells and in fluid.
Sometimes it will be found desirable to preserve longer portions of intestine
than can be contained in cells of the usual size ; for this purpose, the built-
up cells already described will be of service, as they can be made of almost
any size.
When the villi are long and well filled, the vessels are sometimes beauti-
fully shown in transverse sections, mounted in balsam without heat.
Plate LXXIV., fig. 5, Villi of duodenum.
" " fig. 6, Villi of jejunum.
Plate LXXV., fig. 1, Villi of ileum.
" " fig. 2, Muscular fibre of small intestine.]
ORGANS OF THE SENSES. 197
ART. XXII.— ORGANS OF THE SENSES.
Papillary Structure of the Skin.
The sense of Touch is the simplest as well as the most universally-
diffused of the senses, it not merely extending over every portion of
the external surface of the body, but also over certain of the internal
mucous surfaces, as those of part of the mouth, nose, &c.
Over the general surface of the body this sense exists under the
form of common sensation; and it is only in certain parts, as on the
palmar and plantar surfaces of the hands and feet, that it becomes so
highly developed as to assume the importance of a distinct sense, and
to deserve the name of Touch.
This sense has its seat in the papillary structure of the skin, and
the degree of the development of this structure, as shown by the size
and number of the papillae, is always proportionate to the degree of
perfection of the sense : thus, the papillae over the general surface of
the body are much less numerous and less perfect in form than they
are in the palms of the hands and soles of the feet.
The papillae in the natural state are of course invested by the
epidermis, which indeed conceals them to a great extent from view;
this requires to be removed by maceration before their form, size, and
arrangement can be clearly ascertained.
After the removal of the epidermis, it will be seen that the papillae
on the general surfaces of the body do not follow any definite arrange-
ment, but are scattered here and there without apparent order, more
or less thickly according to the degree in which the part of the integu-
ment upon which they are seated is endowed with sensation, but
every where they are less numerous than on the palmar and plantar
surfaces of the hands and feet. (See Plate LXIII.jftg-. 4.)
On the palms of the hands and soles of the feet, the papillae are
arranged, as may be seen with the naked eye, in lines or ridges, each •
ridge being made up of two rows of papillae in single file, and between
each pair of which a further line of separation may be traced : such
is the general disposition of the papillae in each ridge ; the ducts of
the sudoriferous glands pass through its centre and between the rows
of papillae, the number of these glands and ducts to that of the papillae
being in the proportion of one to four. (See Plate LX.lIl.fig. 3.)
32
498 THE SOLIDS.
The arrangement just described can be well seen on the palms of
the hands by the aid of a lens, even while the epidermis is still
attached to the cutis ; the ridges are seen to be disposed here and
there in beautiful curves, some abruptly coming to a termination, and
others dividing into two distinct ridges, this disposition enabling them
to adapt themselves more accurately to the varying nature of the
surface over which they are extended : along the middle of each ridge,
the apertures of the numerous sudoriferous glands may be seen for
the most part crossed in the direction of the diameter of the ridge by
a faint groove, which indicates the line of separation of the papillae
into pairs. (See Plate hXlll.Jig. 1.)
Each papilla appears to consist of a prolongation of basement
membrane, and contains in its interior granular and nuclear contents
and a single looped blood-vessel, (see Plate LXIII. Jigs. 3. 7) : these
points of structure are all made out readily enough; the chief difficulty
consists in the determination of the manner in which the nerve fila-
ments, with which the papillae are undoubtedly supplied, terminate in
them. On this subject, Messrs. Todd and Bowman* have the follow-
ing observations: — "In regard to the presence of nerves in the papillae
themselves, we can affirm that we have, distinctly traced solitary
tubules ascending among the other tissues of the papillae about half
way to their summits, but then becoming lost to sight, either by simply
ending, or else by losing the white substance of Schwann, which alone
enables us to distinguish them in such situations from other textures.
Thin vertical sections of perfectly fresh specimens are essential for this
investigation, and the observer should try upon them the several effects
of acetic acid and solution of potass. In thus describing the nerves-of
the papillae from our own observations, we do not deny the existence
of true loop-like terminations as figured by so respectable an authority
as Gerber ; but neither do we feel entitled to assent to it. . . . We
incline to the belief that the tubules, either entirely or in a great
measure, lose the white substance when within the papillae."
Messrs. Todd and Bowman further observe, in reference to the
structure of the papillae : — " Within the basement membrane it is
difficult to distinguish any special tissue, except by artificial modes of
preparation. A fibrous structure, however, is apparent, having a
more or less vertical arrangement ; and with the help of solution of
potass, filaments of extreme delicacy, which seeem to be of the elastic
kind, are generally discoverable in it."
* Physiological Anatomy, p. 412.
ORGANS OF THE SENSES. 499
The blood-vessels of the papillae consist of single loops; each of
these is made up of an artery and a vein: the former, derived from
the arterial plexus of the cutis, ascends the papilla on one side, and
on reaching its summit gradually merges into the vein which descends
along its opposite side, and terminates in the venous plexus of the
cutis. In an injected preparation, and where the villi are large, the
turn of the loop is seen to be very abrupt, the two vessels, the artery
and the vein, coiling round each other, and resembling a piece of
twine which has been bent upon itself and afterwards twisted in a
spiral manner. This disposition of the vessels seems intended to
delay somewhat the passage of the blood through the papillae. (See
Plate imil.jig. 7.)
The thickness of the epidermis which so closely invests the papillae,
does not appear to have any direct relation to the sense of touch f
thus, over the general surface of the body, where this sense exists
only as common sensation, the epidermis is very thin, while over the
palmar surface of the hands it is very thick; the epidermis must not
be too thick, however, even in this situation, as is shown by the fact,
that where it has been greatly thickened by manual labour, touch is
totally obscured.
The density of the epidermis in certain situations is evidently due
to pressure, and may be explained by the fact that such pressure
induces an increased determination of blood to the part, which is
followed by increased nutrition and development. Between the
sense of touch and the number of sudoriferous glands, there would
appear to be a certain relation: thus, on the palmar aspect of the
hands, where this sense exists in its highest perfection, the number of
sweat glands is very great.
The use of these glands in this situation in such increased numbers,
may readily be conceived to be to keep the epidermis in a moist and
flexible condition, whereby impressions would be more readily con-
veyed to the papillae and more distinctly felt, the acuteness of the
entire sense being thus greatly augmented.
The epidermis is very accurately adapted to the papillae, so that
when detached and viewed upon its under surface, it is seen to con-
tain exact impressions of each and all of them; it is in this manner
that their form, size, number, and arrangement are best studied, and
it will then be noticed that, in all these particulars, considerable
variations exist. (See Plate LXIII. Jigs. 5, 6.)
500 THE SOLIDS
PAPILLA OP SKIN:
[The papillse of the skin may be examined in their recent state on
detaching the epidermis after slight maceration : the papillse may then be
viewed in thin transverse sections of the skin, as directed in the prepara-
tion of the sudoriparous glands. The loopings of the vessels investing the
papillse, can only be seen after injection. In some cases of very success-
ful minute injection of the whole body, the capillaries of the skin will be
found filled; but this success is rare, except in foetal subjects. Injections
of the skin may sometimes be made of one extremity — as one arm, or a
hand or foot. In these attempts, the injection must be made by the vein.
When success is obtained, those portions of skin that show best the papillae,
and these will be found on the palmar surface of the hand and fingers,
may be preserved in cells with fluid. Other portions should be allowed to
dry, and transverse sections made and mounted in balsam.]
ORGANS OF THE SENSES. 501
Papillary Structure of the Mucous Membrane of the Tongue.
The mucous membrane of the tongue, the principal, if not the sole
seat of the sense of taste, is divisible, like the skin, into a chorium, a
papillary structure, and an epidermis or epithelium.
The chorium is a firm and tough membrane, formed of mixed fibrous
tissue, and containing in its substance the blood-vessels and nerves,
arranged in a plexiform manner, from which the papillae are supplied :
to its under surface the extremities of the mascular fibres of the mus-
cles of the tongue are firmly attached; this arrangement imparts to
the whole organ a considerable power of movement and of nice
adaptation.
The papillary structure, which is the real seat of the sense of taste,
is constituted of an immense number of papillae, which occasion a
somewhat flocculent appearance of the whole surface of the tongue.
The papillae are divisible into simple and compound, and the latter
again into filiform, fungiform, and calyciform; besides these several
compound forms, however, others exist of no very definite shape, but
approaching more or less closely in their characters to either the
fungiform or calyciform papillae.
The simple papillae exist principally on the sides and under surface
of the tongue, but also, though more sparingly, on its upper surface,
as between the filiform papilae, in the space around the base of each
fungiform papilla, and for a short distance behind the calyciform
papillae, and to either side of them. (See Plate LXY.fig. 10.)
They vary somewhat in size, form, and structure in difFerent situa-
tions ; in general they are much pointed at their extremities : behind
the calycform papillae they are obtuse and pyriform in shape, (see
Plate LXV. fig. 11,) while on the under surface of the tongue their
extremities are very frequently perforated, and they appear to serve
the double purpose of a papilla and mucous follicle. (See Plate LXV.
fig- 2.)
They each consist of, in addition to their epithelial investment, a
layer of basement membrane, a single looped blood-vessel, filaments
of nerves, and granular and nuclear contents. (See Plate LXV. fig.
6; and Plate LXVI.^g-. 5.)
The compound papillae are confined to the upper surface and edges
of the tongue, and do not extend, except for a short distance at the
502 THE SOLIDS.
sides, over the space bounded in front by the calyciform papillae, and
behind by the epiglottis. This chain of papillae forms the extreme
boundary of the space over which the sense of taste extends, the surface
behind it being smooth, non-papillary, and exhibiting numerous open-
ings of mucous glands; thus then it would appear we have a true
gustatory region.
Each compound papilla is made up of numerous simple papillae,
arranged differently in the case of the three forms of these already
enumerated.
The filiform papillae are by far the most numerous, being more
than in the proportion of twenty to one ; when freed from epithelium
they are seen to be more or less cylindrical in form, and to consist
of a variable number of simple papillae, from sixteen to twenty or
more to each, arranged in a single circular series, forming the top and
margin of the cylinder. (See Plate LXIV. fig. 3.) The sides of the
simple papillae are more or less united together, but the tips are free
and pointed, some more so than others.
The length of the cylinder which each filiform papilla describes, the
degree of acumination of the apices of the secondary papillae, and the
extent of these which is free, vary in accordance with the position of
the papillae on the tongue.
The circular disposition referred to is best seen in the papillae placed
near the tip and sides of the tongue, for in those situations the sec-
ondary papillae are short, blunt, and nearly of equal lengths. (See
Plate LXIV. fig. 3.) In the centre of the organ the simple or second-
ary papillae are much longer, and more slender, so that they fall
together and variously intermix with each other, and thus it is that
the circular disposition in them is usually more or less concealed from
view. (See Plate LXIV. fig. 4.)
This disposition of the secondary papillae includes of course, as a
consequence, a corresponding arrangement of the blood-vessels, (a
single looped vessel proceeding to each,) and of the nerve filaments,
which are in like manner arranged in circles. (See Plate LXVI.
fig- 4.)
The centre of each filiform papilla is hollowed out, and is to be
regarded as a large mucous follicle, and thus the comparison of these
papillae to a cylinder is rendered almost complete. (See Plate LXIV.
fig- 3.)
We shall presently see that the same circular arrangement extends
ORGANS OF THE SENSES. 503
to the filiform epithelial appendages hereafter to be described, and one
of which corresponds to each secondary papilla.*
The fungiform papillae are seated principally on the tip and sides
of the tongue, at least they are most evident in those situations, and
around each a space or shallow fossa, dotted with numerous simple
papillae, may be observed ; they are distinguished from the filiform
papillae by which they are surrounded, by their form, being narrow
at the base, and dilated near the summit, by being clothed all over
with simple papillae, which are usually a good deal compressed in
form, and by the tenuity of the epithelium, destitute of filiform append-
ages, which covers them, and which allows of the blood in the vessels
being seen through it. (See Plate LXIV. jig. 5.)
At the edges of the tongue, and at the sides behind the calyciform
papillae, compound papillae exist, which bear some resemblance to the
fungiform papillae, of which they may be described as modifications;
they differ from ordinary fungiform papillae, however, in being sessile
and simply rounded; in the form of the simple papillae which clothes
them, and which usually are not compressed, but swollen at the
extremity, or pyriform. (See Plate LXV. jig. 11.)
The calyciform papillae bound the true gustatory region posteriorly ;
they are seven or eight in number, and arranged in two rows, which
meet behind in the foramen caecum, and enclose a V-shaped space,
the concavity of which looks forward.
They each consist of a depression or cup, out of which a large
papilla, sometimes more or less adherent to the rim of the cup, arises,
and the level of which it but little exceeds ; the central papilla, as well
as the sides and margin of the cup, are closely set with very many
simple papillae, which are short, obtuse, and dilated at their extremities.
A calyciform papilla, perfectly freed from epithelium, and with all the
secondary papillae visible, forms a very beautiful object. (See Plate
hXVI.Jg. 1.)
The foramen ccecum usually contains one and sometimes two large
papillae, similarly clothed with secondary papillae, and according as
it includes one or two papillae, it is to be regarded as a single or
double modified calyciform papilla.
In front of the calyciform papillae, in some tongues, a number of
large and irregular papillae exist, invested with secondary papillae
* The form and structure of the filiform papilla, as above detailed, was first
described by me in the Lancet of 3d March, 1849.
404 THE SOLIDS.
similar to those of the calyciform papillae, but not, like the latter, seated
in cups.
On the edges and under surface of the tongue numerous mucous
follicles are observed : it is sometimes, however, difficult to distinguish
between these and simple papillae, in consequence of the latter being
frequently perforated in the centre, and thus combining the charac-
ters of both follicles and papillae. (See Plate LXV.figs. 1, 2, 3.)
The epithelial investment of the tongue adheres very closely to the
papillae, and generally requires one or two weeks' maceration for its
complete removal; even then, in but few instances in the human sub-
ject, can it be removed in entire pieces, it in most cases crumbling
away into its constituent cells.
It adapts itself accurately to the papillary structure of the tongue,
and is of sufficient thickness to conceal effectually the simple papillae,
whether these exist by themselves or constitute by their aggregation
the compound papillae. For the satisfactory study of the papillae,
therefore, it is absolutely necessary that the epithelium should be
entirely removed.
The epithelium of the tongue presents all the characters of the
epidermis of the skin, consisting, like it, of numerous layers of large
and nucleated cells, those forming the outer layers being flattened and
membranous, while the deeper-seated cells are rounded and granular.
(See Plate LXY.fig. 6.)
The thickness of the epithelium of the tongue in the human subject
varies very considerably in different cases, and would appear to be
much affected by disease; it in some cases even being entirely absent.
It is thickest over the simple papillae, which are usually entirely
concealed by it ; over the fungiform and calyciform papillae it is very
thin and delicate, while over the filiform papillae it is prolonged into
long filiform processes, which correspond in number and arrangement
with the secondary papillae themselves. (See Plate LIV. fig. 1, 2.)
These filiform appendages vary much in length, being very short
upon the sides and near the tip of the tongue, but three or four times
as long near its centre (see Plate LIV. fig. 1,2); at the very tip they
are often entirely wanting, the papillae in this situation presenting the
appearance of large open follicles with slightly spinous rims. (See
Plate LV. fig. 4.)
Each filiform process is constituted of flattened epithelial scales,
which lie in the direction of their length, and frequently contains a
canal in its centre.
ORGANS OF THE SENSES. 505
Tubular nerve filaments, terminating in loops, have been discovered
in the fungiform and filiform papillae, but not hitherto in either the
simple or calyciform papillae, although nerve filaments, in some form
or other, doubtless exist in these also.
The internal minute structure of the three principal forms of com-
pound papillae requires a careful and searching examination, with a
view to the determination of their respective functions. From a con-
sideration of their outward configuration, they would all appear to be
w.^11 adapted to receive gustatory impressions. The fungiform papillae
set m to be so by their prominence and the delicacy of the epithelium
by vhich they are invested, the calyciform papillae also by the tenuity
of tl eir epithelial covering and by their cupped form, and the filiform
papi^ae, by reason of the cavity which occupies the centre of each,
and tiie regular disposition of the secondary papillae around this.
An\ additional, and to my mind, indeed, an almost conclusive reason
in fav bur of the subserviency of the filiform papillae to the reception of
gustatory impressions, is derived from the consideration that they
cover nineteen-twentieths of the mucous membrane of the tongue",
and it is but natural to suppose that the principal portion of this is
destined to the discharge of the function for which it has so evidently
been designed.
The filamentary papillae have generally been considered to be ill
adapted to the reception of gustatory impressions, in consequence of
the character of the epithelial processes in connexion with them ; and
it has been supposed that they are to be regarded as tactile rather
than gustatory organs. This opinion has, however, been entertained
in the absence of a full knowledge of the real form and structure of
these papillae, as already shown.
It has occurred to me that these filamentary processes act as
absorbents of the nutrient juices, and that collectively they constitute
an absorbent surface of considerable power, conveying directly to the
papilla those fluids, and keeping them in contact with the papillae for
a time, thus prolonging the duration of the gustatory impression.
This idea would appear to gather confirmation from the fact that it is
in these filamentary epithelial prolongations tljat the variable coating
known as the fur of the tongue has its seat.
SMELL.
Structure of the Mucous Membrane of the Nose.
The anatomical characters of the mucous membrane of the nose
500 THE SOLIDS.
differ in different regions; for a short distance within the anterior
nares, the mucous membrane presents many of the characters of the
skin, it being divisible into chorion, papillary structure, and epider-
mis; the papillae resemble in every respect those of the sense ol
touch, and the epidermis consists of flattened epithelial scales analo-
gous to those of the same structure in the skin. This, the commence-
ment of the nasal mucous membrane, may be called the tactile
region of the nose, and it is abundantly furnished with hairs, which
guard the entrances of the nares, and the roots of which are in con-
nexion with the ordinary sebaceous glands of the hair follicles.
Higher up the mucous membrane of the nose, losing its papillae and
scaly epithelium, becomes thick and soft, and presents more completely
the ordinary appearances of a mucous membrane ; imbedded in its
substance are numerous mucous follicles of large size, having but
small apertures, which are best seen thickly studding the surface of
the membrane after slight maceration and the removal of the epithe-
lium. Between and around these the blood-vessels are disposed, the
veins being particularly large, and forming a very evident plexus, each
mesh of which corresponds with a follicle. (See Plate LX1X. fig. 2.)
The large size and considerable numbers of the mucous follicles
explain the copious secretion which proceeds from this portion of
the mucous membrane, when suffering from irritation, while the
venous plexuses sufficiently account for the disposition of this part
to hemorrhage.
This is by far the largest of the three nasal regions, and may be
denominated the jriluita?-y ; the epithelium which clothes it is of the
ciliated kind, and several of the cavities in connexion with the
meatuses are invested by a similar epithelium, as the frontal and
sphenoidal sinuses, the antrum maxillare, and the Eustachian tubes.
In the sinuses, however, the mucous membrane, losing its follicles,
becomes much reduced in thickness, and presents the characters of a
fibrous rather than of a mucous structure.
Still higher up in the nose we come upon the third region, which has
been particularly defined and described by the authors of the Physi-
ological Anatomy as follows, under the name of the olfactory region:
"The olfactory region is situated at the top of the nose, imme-
diately below the cribriform plate of the ethmoid bone, through
which the olfactory nerves reach the membrane; and it extends about
one-third or one-fourth downwards on the septum, and over the supe-
rior and part of the middle spongy bones of the ethmoid. Its limits
ORGANS OF THE SENSES. 507
are distinctly marked by a more or less rich sienna-brown tint of the
epithelium, and by a remarkable increase in the thickness of this
structure, compared with the ciliated region below ; so much so, that
it forms an opaque soft pulp upon the surface of the membrane, very
different from the delicate, very transparent film of the sinuses and
lower spongy bones. The epithelium, indeed, here quite alters its
character, being no longer ciliated, but composed of an aggregation of
superposed nucleated particles, of pretty uniform appearance through-
out ; except that in many instances a layer of those lying deepest, or
almost deepest, is of a darker colour than the rest, from the brown
pigment contained in the cells. These epithelial particles, then, are
not ciliated; and they form a thick, soft, and pulpy stratum, resting
on the basement membrane. The deepest layer often adheres after
the others are washed away. On looking on the under surface of
this epithelium, when it has been detached, we observe projecting
tubular fragments similar to the cuticular lining drawn out of the
sweat-ducts of the skin, when the cuticle is removed after macera-
tion. In fact, glands apparently identical with the sweat-glands exist
in this region in great numbers. They dip down in the recesses of the
sub-mucous tissue, among the ramifications of the olfactory nerves;
and their orifices are very easily seen, after the general brown coat
of epithelium has been detached, lying more or less in vertical rows;
the arrangement is probably determined by the course of those nerves
beneath. They become more and more sparing towards the limits of
the olfactory region. The epithelium of these glands is bulky, and,
like that of the sweat-glands, contains some pigment. As the duct
approaches the epithelium of the general surface, its wall becomes
thinner and more transparent, and in its subsequent course upwards,
it is difficult to be traced, for it does not appear to be spiral, or its par-
ticles to differ from those which they traverse. We have sometimes
seen rods of epithelium, apparently hollow, left projecting from the base-
ment membrane, after the brown epithelium has been washed away,
and these are perhaps portions of the excretory ducts of these glands."
In the propriety of the discrimination of this region, and in the
accuracy of much of the description of it given above, the author
fully concurs. He does not, however, hesitate to affirm that no
glands at all analogous to sweat-glands exist in it; the membrane of
this region is indeed thickly studded with mucous follicles, apparently
in no respect dissimilar to those of the pituitary region, except that
they are smaller in size, and more delicate in structure.
508 THE SOLIDS.
The chief characteristics of the olfactory region consist, then, in
its glandular epithelium, in the presence of pigment cells lying be-
neath this, in its more delicate structure, in the presence of gelatinous
nerve filaments, and in a somewhat different arrangement of the
blood-vessels. (See Plate LXIX. fig. 1.)
In the sheep this region is rendered almost black by the presence
of very many pigment cells which are of the stellate form.
Mr. Quekett pointed out, some years ago, the very curious fact that
the blood-vessels of the olfactory region of the human foetus, and that
of mammalia in general, are disposed in loops, the convexity of each
of these presenting a decided dilatation. (See Plate LXIX. fig. 12.)
Much interest is attached to the existence of these loops, since they
appear to indicate the presence of true papillae in the seat of smell of
the mammalian foetus ; if such be the case, however, it is very cer-
tain that neither the papillae nor loops exist in the olfactory region in
the adult condition of the nasal organ.
The most rigorous search has failed to detect the presence in the
olfactory region of cells, which could be decidedly pronounced to be
nervous or ganglionic.
The nerves of the nose are the first pair, branches of the fifth, and
motor filaments from the seventh pair. The first pair are, doubtless,
the proper nerves of smell, while the fifth gives common sensibility to
the nose.
The olfactory lobes are prolongations of the white or fibrous por-
tion of the brain, and consist, like it, of slender tubular nerve fila-
ments, intermixed with the delicate transparent cells, described in a
previous division of this work.
" The olfactory filaments are from fifteen to twenty-five in number,
and passing through the apertures of the cribriform plate, may be
seen invested with fibrous sheaths derived from the dura mater, upon
the deep or attached surface of the mucous membrane of the olfac-
tory region. They here branch, and sparingly reunite in a plexiform
manner, as they descend. They form a considerable part of the
entire thickness of the membrane, and differ widely from the ordinary
cerebral nerves in structure. They contain no white substance of
Schwann, are not divisible into elementary fibrillae, are nucleated,
and finely granular in texture ; and are invested with a sheath of
homogeneous membrane, much resembling the sarcolemma, or, more
strictly, that neurilemma which we figured from the nerves of insects
in a former volume. These facts we have repeatedly ascertained, and
ORGANS OF THE SENSES. 509
they appear to be of great importance to the general question of the
function of the several ultimate elements of the nervous structure,
especially when viewed in connexion with what will be said on the
anatomy of the retina. We are aware that some anatomists deny the
existence of the white substance of Schwann as a natural element of
the nerve fibre in any case, pretending that it is formed by artificial
modes of preparation. We hold it to be a true structure, but how-
ever that may be, these nerves never exhibited it, however prepared.
They rather correspond with the gelatinous fibres. Now, there is no
kind of doubt that they are a direct continuation from the vesicular
matter of the olfactory bulb. The arrangement of the capillaries in
well-injected specimens is a convincing proof of this, as these vessels
gradually become elongated on the nerve assuming a fibrous charac-
ter as it quits the surface of the bulb ; and, further, no tubular fibres
can ever be discovered in the pulp often left upon the orifices of the
cribriform plate after detachment of the bulb. It must be remembered
that a few tubu • nbres from the nasal nerve of the fifth here and*
there accompany the true olfactory filaments ; but these only serve
to make the difference more evident by contrast.'5 — Physiological
Anatomy.
VISION.
Structure of the Globe of the Eye.
The structure of the several appendages of the globe of the eye : as -
the eye-lids, with their lashes, and Meibomian glands, the caruncula
lacrymalis, the lachrymal gland, muscles, &c, have already been fully
described in previous sections of this work ; we have now to enter
upon the description of the numerous parts which compose the essen-
tial portion of the organ of vision, the globe of the eye ; each of these
may be examined in much the same order in which they would natu-
rally present themselves to the notice of an ordinary dissector, and
which would be somewhat as follows : Sclerotic and cornea ; cho-
roid, ciliary processes, and iris ; retina ; crystalline lens ; hyaloid
membrane, &c.
Sclerotic.
The sclerotic is composed, to a great extent, of white fibrous tissue,
intermixed with a small proportion of a nucleated form of elastic tissue.
These tissues are disposed in a laminated manner, the fibres of one
layer crossing those of another more or less at right angles ; — an
arrangement evidently designed to render this the protecting tunic of
the eye more firm and unyielding. The inner surface of the sclerotic
510
THE SOLIDS.
is rough, and connected with the choroid by the lamina fusca of that
membrane, to be described hereafter.
The nutrition of the sclerotic is provided for by small vessels which
ramify on its outer surface, and which are sparingly continued into
its substance.
Anteriorly, the sclerotic is strengthened by the tendinous expan-
sion of the four recti muscles, known as the tunica albuginea, or
white of the eye.
Cornea.
The cornea, although in a state of health as clear as crystal, yet
possesses a complicated and beautiful organization, plainly demon-
strable with the aid of the microscope.
Notwithstanding also the definite line of demarcation by which the
limits of the cornea and sclerotic are marked out, these two parts are
yet inseparably united to each other ; this indissoluble union depend-
ing upon the circumstance of the existence of a structural connexion
between them, the nature of which will shortly be rendered evident.
The cornea is clearly divisible into four, and, according to some
observers, even five laminae. These are, reckoning from before
backwards, conjunctival epithelium, cornea proper, posterior elastic
lamina, and the epithelium of the aqueous humour ; the fifth layer has
been described in the " Physiological Anatomy" under the title of
the " anterior elastic lamina." These several layers will be separately
noticed, and in the order mentioned. (See Plate LXVII. fig. 1.)
The conjunctival epithelium forms a distinct membrane of appre-
ciable thickness, and capable of separation as such shortly after death.
It consists of several layers of super-imposed cells, which partake of
many of the characters of ordinary epidermic scales or cells.
Those cells which constitute the outer or more superficial layers
are large, flat, and membranous ; while those nearest to the cornea
proper, and which appear to rest directly upon it, are baton-shaped,
and disposed vertically to the surface of the cornea. (See Plate
LXVIII. figs. 3. 5, and Plate LXVII. fig. 1.)
After death this epithelium becomes whitish and opaque, and it
then forms the film of the eye.
The second lamina, according to the observations of the author, is
the cornea proper ; and it is this which constitutes the principal bulk
of that structure.
Externally, the cornea proper is firm and dense in texture, but
becomes more lax and soft gradually as we approach the interior; it is
ORGANS OF THE SENSES. 511
this external and firmer portion which exhibits the lamellar arrange-
ment so generally described, the fibres following a less regular course
internally, and being separated by wider intervals.
The tissue of the cornea has been recently described as a peculiar
modification of the white fibrous element of the sclerotic. It would
appear, however, that the fibrous tissue of which it is constituted is
of a kind totally distinct from that which enters so largely into the
composition of the cornea proper ; a conclusion derived from its
examination, for which we might be prepared, simply by the consider-
ation of the very opposite physical characters of the two parts, the
sclerotic and cornea, the former being white and opaque, and the
latter clear and diaphanous.
If we tear up with needles a small portion of the sclerotic, and
examine it with the microscope, we then see that it is made up, for
the most part, of bundles of wavy and distinct fibres, presenting
scarcely a nucleus, and reflecting a yellowish hue; if now we carry
our examination still further, and apply acetic acid to these bundles,
they swell up, the fibres becoming indistinct, and finally converted
into a jelly-like substance.
On the other hand, if we submit a portion of the cornea to the same
examination, and the same treatment by acetic acid, we shall encoun-
ter different appearances and results. In the first place, we shall not
perceive distinct and separate bundles of fibrous tissue free from
nuclei, but we shall merely notice an indistinct fibrous character in
the mass, with here and there elongated nuclei imperfectly seen; on
the application of acetic acid, however, the fibres become much more
evident, and multitudes of nuclei are brought into view. Thus, then,
it is evident that the tissue of the cornea is something more than a
modification of the white fibrous element of the sclerotic. The nucle-
ated fibres just described are often, in the neighbourhood of the nuclei
themselves, expanded and membraneous ; and it is remarkable that they
do not lie in direct apposition with each other, but interlace in such a
manner as to describe elongated spaces, several of which are extended
in the same line. These spaces are oval in the cornea, and round in
that portion of the sclerotic where the two structures are in connexion
with each other.* (See Plate LX.YU.Jig. 3.)
* A subsequent examination of the cornea renders it necessary that the views
above expressed of its structure should be modified to some extent. I find that a
considerable amount of a tissue, wry closely resembling the white fibrous tissue of
the sclerotic, does enter into the construction of the cornea ; in sections, however,
512 THE SOLIDS.
This arrangement was first pointed out by the authors of the
"Physiological Anatomy," and is thus described by them. "On the
cornea proper or lamellated cornea, the thickness and strength of the
cornea mainly depend. It is a peculiar modification of the white
fibrous tissue, continuous with that of the sclerotic. At their line of
junction, the fibres, which in the sclerotic have been densely inter-
laced in various directions, and mingled with elastic fibrous tissue,
flatten out into a membraneous form, so as to follow in the main the
curvatures of the surfaces of the cornea, and to constitute a series of
more than sixty lamellae, intimately united to one another by very
numerous processes of similar structure, passing from one to the other,
and making it impossible to trace any one lamella over even a small
portion of the cornea. The resulting areola?, which in the sclerotic
are irregular, and on all sides open, are converted in the cornea into
tubular spaces, which have a very singular arrangement, hitherto
undescribed. They lie in superpose planes, the continuous ones of
the same plane being, for the most part, parallel, but crossing those of
the neighbouring planes at an angle, and seldom communicating with
them. The arrangement and size of these tubes can be shown by
driving mercury, or coloured size, or air into a small puncture made
ill the cornea. They may also be shown under a high power by
moistening a thin section of a dried cornea, and opening it out by
needles." In addition to the above it may be remarked, that the
spaces may be seen without injection, or any other preparation, even
in perfectly fresh eyes.
In vertical sections of the cornea, after the application of acetic
acid, the nucleated fibres in its outer or denser portion are seen to
follow the curved form of the cornea itself, while in its inner and softer
part they are variously disposed; horizontal sections of the cornea,
even taken from the surface, exhibit a curved and interlaced arrange-
whether treated or not with acetic acid, this tissue is scarcely to he traced, the nuclear
form of fibrous tissue already described, and which is so very abundant, being alone
visible, and appearing to constitute the entire of its substance. If, however, a small
piece of the inner and softer part of the cornea be torn up with needles, and then
examined, bundles of fibrous tissue, very analogous to those of the white fibrous
form, will be plainly seen; these are of considerable diameter, reflect a greenish
shade, and are, in many parts, transversely straited, each filament bearing a resemblance
to a minute Conferva ; they are rendered nearly, though not quite, invisible by the
action of vinegar. Considered altogether, the cornea resembles very closely, in
structure, a tendon, which also contains a very large quantity of a similar nuclear
fibrous tissue.
ORGANS OF THE SENSES. 5 i U
ment of the fibres ; fibres, also nucleated, pass from the surtace of the
cornea deeply into its substance : the use of these is doubtless to assist
in preserving its convexity. (See Plate LX.Vll.Jig. 1.)
The posterior elastic lamina is the third layer of the cornea: it is
a perfectly transparent membrane of appreciable thickness, so that it
may be readily recognised with the unaided sight, and is but slightly
attached to the cornea proper.
It is usually described as structureless, and in most cases it certainly
is so; but in the human eye it frequently exhibits peculiar markings,
portrayed in Plate LXVII. Jigs. 11, 12. These, however, would
appear to proceed from definite inequalities of the surface, rather than
from any distinct fibrous or cellular tissue; nevertheless, the appear-
ances observed are remarkable, and worthy of record.
This lamina preserves its transparency even in boiling water and
acetic acid ; and a further peculiarity is, that although it may be torn
in any direction, it is so hard that it can be bitten through only with
difficulty. It extends to the margin of the cornea only, where it
comes into connexion with certain elastic fibres to be described
hereafter.
The epithelium of the aqueous humour is the fourth layer of the
cornea: this is of such delicacy and tenuity as to be readily over-
looked; it consists of angular cells which form a tessellated epithelium,
and rests upon the posterior surface of the elastic lamina above
described. (See Plate LXVIII. Jig. 11.) This epithelium is doubtless
concerned in the secretion of the aqueous humour, but it does not
appear to extend beyond the limits of the elastic lamina.
The fifth layer, to which reference has already been made, is the
anterior elastic lamina, which is described in the third part of "Physi-
ological Anatomy," as follows : " This is a transparent homogeneous
lamina, coextensive with the front of the cornea, and forming the
anterior boundary of the cornea proper. It is a peculiar tissue, the
office of which seems to be that of maintaining the exact curvature of
the front of the cornea; for there pass from all parts of its posterior
surface, and in particular from its edge, into the substance of the
cornea proper, and sclerotic, a multitude of filimentous cords, which
take hold, in a very beautiful artificial manner, of the fibres and mem-
branes of those parts, and serve to brace them and hold them in their
right configuration. These cords, like the elastic lamina of which
they are productions, appear to be allied to the yellow element of the
areolar tissue. They are unaffected by the acids. The anterior elastic
33
514 THE SOLIDS.
lamina sustains the conjunctival epithelium which covers the cornea,
and is very probably a representative of the basement membrane of
the mucous system, as it occupies the corresponding position in regard
to the epithelium."
The writer has made diligent and repeated search for this lamina,
or for any structure resembling it, without success, however; and he
has no hesitation in asserting his disbelief in the existence of any
membrane in the slightest degree analogous to the posterior elastic
lamina in the situation indicated: he is not prepared, however, to deny
the presence of an exceedingly thin layer of structureless basement
membrane, although of this even he has not yet discovered any
evidence, but conceives it possible that it may exist. Its detection
has been attempted in several ways; namely, by vertical and hori-
zontal sections, and by the use of reagents, but to no purpose.
In a representation of a vertical section of the human cornea, given
in the "Physiological Anatomy," this anterior elastic lamina is
represented as being three or four times the thickness of the posterioi
lamina, so that there ought to be but little difficulty in its detection,
were it present on the face of the human cornea.
The "elastic cords" mentioned would appear to be nothing more
than the nucleated fibres, already described as passing in a curved
manner from the surface of the cornea, and extending deeply into its
substance. (See Plate LXVII. fig. 1.)
Choroid.
The next membrane met with, in the usual order of dissection, is
the choroid: this adheres intimately to the sclerotic in the neighbour-
hood of the larger trunks of the venae vorticosse; but more slightly in
the intervals between, being united to it only by the lamina fusca.
The choroid forms a thick membrane, externally of a chocolate-
colour, flocculent and rough, but internally of a bluish-black colour,
and smooth ; its substance is made up of numerous blood-vessels, and
of an immense quantity of pigment in connexion with a peculiar form
of fibrous tissue.
The tissue of which the choroid is composed, has been hitherto
stated to resemble the fibrous tissue of the sclerotic : this is not the
case, however, as indeed might have been inferred from the ease with
which it tears, especially in the course of the vessels, and the absence
of bundles of fibres on the torn and divided margins: the fibrous
element of the choroid is of a peculiar kind, to be more fully described
hereafter, and unlike any other form existing in the human body.
ORGANS OF THE SENSES. 515
The blood-vessels of the choroid are usually described as forming
two layers, and this they may be fairly considered as doing, although
the two lamellae are not perfectly distinct from each other, being con-
nected by numerous blood-vessels which pass between them.
These laminae may be designated in general terms separately as
arterial and venous ; the inner or arterial lamina, known as the tunica
Ruyschiana, consists of a dense and beautiful plexus of vessels, which
are so closely applied to each other as scarcely to leave any inter-
vening spaces or meshes. (See Plate LXVII. fig. 4.) The main
arteries which supply this tunic, and the veins which carry off its
blood, leave it by numerous points on its outer surface only ; the veins
are particularly large and numerous, and disposed in beautiful curves,
whence they are called venae vorticosce. (See Plate X.LYIII. Jig. 2.)
Before leaving the choroid, they converge to form four or five principal
trunks which enter the sclerotic; the arteries, fewer in number and
much smaller in size, run between the veins.
An immense number of granular nuclei are visible in the walls of
the venae vorticosae.
Stellate Choroid Epithelium. — Such is the distribution of the blood-
vessels of the choroid : the next most important element in its consti-
tution are the pigment cells ; these exist in vast quantities, and make
up much of its substance ; they are of various forms and sizes ; but
being furnished with two, three, or more arms or radii, they may be
aptly termed stellate. The nucleus in each cell is large and particu-
larly clear, appearing almost like a hole in its centre: this is owing to
the absence of the colouring matter contained in each cell in that
situation.
The existence of the stellate form of pigment cells in the human
subject appears to have been generally overlooked: it was described
and figured in Parts VII. and VIII. of the Microscopic Anatomy, pub-
lished in February and March, 1847, and its arrangement in rows was
at the same time pointed out; its position in the choroid, as well as its
structure, have since been examined with more care, and with the
following results :
This pigment is situated beneath the tunica Ruyschiana, and in the
intervals between the venae vorticosae, which it accurately fills up,,
some of the arms of the cells, as well as occasionally a few of the
scattered cells, intrenching upon the veins : thus, then, its disposition.
is a counterpart of that of the venae vorticosae, the dense rows of cells,
exhibit the same curves, the same mode of branching* and, viewed
516 THE SOLIDS.
altogether with a low object-glass in the eyes of some animals, as the
sheep, nothing can exceed the beauty and elegance of the object thus
presented to our examination. (See Plate LXVIII.^°\ 1.)
With regard to structure, it is remarkable that each radius, or arm
of the cells is prolonged into a colourless fibre, in the course of which
several other cells may be included. (See Plate LXVIII.j^g-. 13.)
This structure is best seen in the lamina fusca, the fibres of which
are all of this nature, and are exceedingly diaphanous, often mem-
branous, much disposed to curl up, and unaffected by distilled vinegar,
beyond undergoing a degree of contraction. All the fibres met with
in the choroid, except those entering into the constitution of the
blood-vessels, are of this peculiar nature.
The inner surface of the choroid is so smooth as to convey the
impression of the existence of a distinct membrane: of this, however,
no satisfactory evidence has yet been obtained, although portions of
membrane apparently devoid of structure, have been seen on the
margins of torn portions of the choroid. If a membrane does really
exist in this situation, it is possible that it is nothing more than the
vessels of the tunica Ruyschiana 'united into a membrane by the
fibres above described.
Hexagonal Choroidal Epithelium. — On the inner surface of the
choroid a layer of cells of a regularly pentagonal, or hexagonal form,
filled with pigmentary granules, exists; these cells are so coherent
that they form a distinct layer, much more evident in the eyes of
some animals, as the sheep, and pig, than in those of man. (See
Plate LXVIII. fig. 12.)
This layer extends over that peculiar structure common to the eyes
of many quadrupeds and fishes, the tapetum lucidum; but in that
situation its component cells are of smaller size, and almost entirely
deprived of colouring matter.
In albinoes the colouring matter is deficient, not only in the cells
of tapetum lucidum, but also in those of the hexagonal and stellate
choroidal epithelium.
The tapetum lucidum is a layer of fibrous tissue implanted upon
the choroid, possessing the remarkable property of refracting un-
equally the rays of light which fall upon it, and hence its brilliancy
and metallic lustre: acetic acid destroys to some extent this pecu-
liarity; the stellate pigment is continued behind the tapetum lucidum,
which singular and beautiful structure acts as a concave reflector,
its use being to economize light, and to cause the rays to traverse the
ORGANS OP THE SENSES. 517
retina a second time, by which means animals possessing it, are
enabled to discern objects in a light which would be insufficient for
the purpose, in the absence of such a provision.
The description of the choroid now given, includes that portion of
it, only, which corresponds to the retina, and which ceases at a line
known as the ora serrata; about the eighth of an inch behind the
margin of the cornea, in front of this line as far as the iris, the choroid
is known as the ciliary body; this is covered behind by a layer of
non-striated muscular fibre, the ciliary muscle (see Plate LXVIII.
fig. 4), and from it the ciliary processes descend.
Ciliary Processes. — These processes, usually reckoned at about sixty
in number, are received into corresponding folds or plaitings of the
hyaloid membrane, called the secondary ciliary processes, and which,
taken altogether, form a circle around the crystalline lens, named after
their discoverer the Zone of Zinn: they are each composed of numer-
ous blood-vessels, (see Plate LXVII. fig. 4), fibrous tissue, irregular
pigment cells ; and "on their inner surface is a tough colourless lamina,
composed of ill-defined nucleated cells continuous with the border of
the retina, but clearly not composed of nervous matter, by means of
which they are immediately connected with the hyaloid membrane."
The iris may be regarded as an* extension of the choroid, although
it does not exhibit all the anatomical characters of that membrane;
it is made up of a considerable quantity of pigment cells, of blood-
vessels, and of fibres of unstriped muscle. (See Plate LXVIII. j^g-. 9.)
The pigment cells constituting the posterior layer of the iris, and
called uvea, are irregular in size and form, as are those also situated
among the fibres of the iris; upon the varieties in the colouring
matter contained in these last, many of the differences observable in
the iris of different persons and animals depend. (See Plate LXVIII.
fig- 14.)
The muscular fibres of the iris in the human subject, are of the
unstriped kind, and follow two courses, a radiating and a circular; in
birds, however, the radiating fibres consist of striped muscular fibres,
and they surround immediately the pupil; the one set of fibres dilates
the pupil, the other contracts it.
The blood-vessels of the iris are very numerous, and are derived
chiefly from the two long ciliary arteries, which, on approaching the
iris, bifurcate and form an arch around it, whence pass inwards a
number of branches which form loops near the pupillary margin.
"On the anterior surface, near the pupil, avascular circle marks
518 THE SOLIDS.
the line from which in the foetus the membrana jmpillaris stretched
across in front of the pupil. This membrane at that early period
divides the posterior from the anterior chamber, and receives from
several parts of the circular vessel last mentioned, small branches,
which approach the centre, and then return in arches, after inoscula-
ting sparingly across the central point." The membrana pupillaris
is almost absorbed at birth.
The iris, according to the authors of the Physiological Anatomy,
"is attached all around at the junction of the sclerotic and the cor-
nea, so near indeed to the latter, that its anterior surface becomes
continuous in the following manner with the posterior elastic lamina.
This lamina, near its border, begins to send off from its anterior sur-
face, or that towards the laminated cornea, a net-work of elastic
fibres, which stretch towards the border, becoming thicker as they
advance, until at length the entire thickness of the lamina is expended
by being converted into them. These fibres then bend backwards
from the wrhole circumference of the cornea, to the circumference of
the front of the iris, and are there implanted, passing in this course
across the line of the anterior chamber, and through the aqueous
humour. They are seen more easily in some animals than in others,
forming a regular series of pillars ftround the anterior chamber."
It would appear, however, that these fibres, which may be readily
detected in the human eye, should rather be described as proceeding
from the sclerotic, and passing, some on the anterior surface of the
elastic lamina, and others on the front of the iris, thus assisting in
uniting these parts to that tunic; it is very doubtful whether they
have any structural connexion with the posterior elastic lamina.
(See Plate LXVIII. fig. 8.)
The ciliary nerves pierce the ciliary muscle on their way to the iris.
Retina.
We come in the next place to the description of the most interest-
ing and important of the many structures which enter into the com-
position of the globe of the eye, namely, the retina. This membrane
may be regarded as the expansion of the optic nerve, to which certain
other structures are superadded, and, like most of the other mem-
branes of the eye, is divisible into distinct lamellae ; these, reckoning
from without inwards, are, tunica Jacobi, or "stratum bacillosum,"
the granular or nuclear layer, the ganglionary layer, the vesicular
layer, the fibrous expansion of the optic nerve, and, lastly, the vascular
expansion of the arteria centralis retinae.
ORGANS OF THE SENSES. 519
The tunica Jacobi is composed of a single stratum of cells of very
remarkable form. They are minute in size, several times longer than
broad, having their long axes disposed vertically to the general surface
of the retina, and they each consist of a body or head of a more or
less globular or oval shape, and of a prolongation or tail, four or five
times longer than the head, and not more than a third of its diameter.
By their coherence these cells form a distinct membrane, the heads of
the cells all being directed one way, namely, towards the surface of
the choroidal epithelium, and the tails disposed in an opposite direc-
tion. Although these cells adhere together with sufficient firmness
to constitute a distinct membrane, it would appear that they possess
a certain power of movement upon each other, for it is only on such
a supposition that we can explain satisfactorily the fibrous appearance
which this membrane frequently presents when viewed in extenso.
(See Plate LXVII. fig. 9.)
The tunica Jacobi, although certainly not a nervous structure, is
yet properly enumerated as one of the layers of the retina, since it
never adheres, on the removal of the latter to the choroidal epithelium,
but always to the second or granular layer of the retina itself: on
account of its extreme frailty and delicacy, this membrane is only to
be satisfactorily studied in extremely fresh eyes. A few hours after
death the cells separate from each other, and the heads of the cells
become disjointed from the tails, so that in the course of a short time
not a vestige of the membrane remains.
Each cell of the stratum bacillosum bears not an inexact resemblance
to a human spermatozoon, than which it is, however, less considerable
in size.
The granular layer consists not of granules merely, as the name
implies, but of numerous nuclei imbedded in granular matter, and each
of which contains several dark spots which reflect the light strongly.
This layer is of considerable thickness, and is described in the " Physi-
ological Anatomy" as being divided into two, of which the inner is
much the narrower, by a pale stratum which can only be seen hj very
careful manipulation. The nuclei of which it is composed bear much
resemblance to those which occur in the convolutions of the brain, and
are most probably of the same nature. (See Plate LXVII. Jigs. 5, 6.)
The next is the ganglionary layer: this appears to have been
hitherto altogether overlooked ; its discovery supplies a desideratum
in the anatomy of the eye, and clearly shows the really nervous char-
acter of the granular and vesicular strata of the retina, which many
persons have been much disposed to doubt.
520 THE SOLIDS.
This layer is exceedingly thin and delicate, hardly indeed to be con-
sidered as a distinct stratum, but yet consisting of numerous caudate
ganglionary globules, in every respect similar, in point of structure, to
those which have been described as occurring in so many of the
ganglia of the human brain.
These caudate cells differ considerably in size, but yet are all
referable to one of two standards, the larger very much exceeding the
smaller in dimensions. (See Plate LXVII. fig. 8.)
It is in the human retina only that these cells have as yet been
detected.
The fourth or vesicular layer lies immediately on the outer surface
of the fibrous layer : the cells composing it are several times larger
than the nuclei of the granular layer; a few of the most external of
them are granular and nucleated, but the majority, and these the larger
cells, are clear and transparent as water, perfectly globular, and without
appreciable nuclei. The cells of the vesicular layer resemble very
closely the delicate cells which have been described in a previous part
of this work, as found in the fibrous portions of the human brain. (See
Plate LXVII. fig. 7.)
The fibrous gray layer is best seen and most strongly marked in
the retina, near to the optic nerve. If a portion of this membrane be
cut off and spread out upon glass, it will be seen to present, viewed
with the inch or half-inch object-glass, a number of parallel or rather
radiating flattened bands, two of which occasionally divide or bifurcate.
If, in the next place, these bands or bundles, having been separated
somewhat from each other by means of needles, and as much of the
granular layer which so obscures them washed away with a camel's-
hair brush as possible, be then examined, they will each be observed to
present a fibrous appearance; and, on a prolonged and careful exami-
nation, it will become apparent that they are made up, first, of a small
quantity of nucleated fibrous tissue; and, secondly, and principally, of
gray gelatinous nerve fibres. (See Plate LXVIII. fig. 6.)
That these gelatinous fibres constitute the principal portion of the
fibrous layer of the retina, and that no tubular nerve fibres exist in
the retina itself, are points upon which not the smallest doubt can be
entertained.
Of the reality of the transformation of the tubular into the gelatinous
nerve filament ; that is, the conversion of a tubular, unbranched, and
unnucleated structure into a branched and nuclear tissue, great mis-
givings might be well entertained; an attentive study of the structure
ORGANS OF THE SENSES. 521
of the fibrous gray layer of the retina renders it very difficult, however,
to deny the reality of such a structural transition.
The vascular lamina is the last of the layers of the retina: it would
appear to be entirely distributed upon the inner surface of the fibrous
layer; for, if we take a perfectly fresh eye, and spread the retina out
with its inner surface upwards, we can readily see the larger blood-
vessels filled with blood corpuscles, and having the fibrous layer situ-
ated immediately behind them. (See Plate LXVII. fig. 2.)
The optic nerves consist of several bundles of nerve tubules : these
are very slender and brittle, and interspersed with delicate globular
cells ; in these last two particulars, these nerves correspond with the
white fibrous portions of the brain.
The transparent media of the eye are the vitreous body and the
crystalline lens with its capsule.
Vitreous Body.
The vitreous humour is enclosed in a perfectly structureless and
exceedingly delicate membrane, called the hyaloid membrane: this
does not enclose the whole of the vitreous humour, but is deficient
behind the crystalline lens, it being inserted into the side of the capsule
of that body.
From all points of the inner surface of this membrane fibres proceed;
these interlace with each other in such a manner as to form a cellated
structure.
The size and structure of these cells may be readily seen with an
inch or half-inch object-glass; and the best view of them is obtained
in the neighbourhood of the zona ciliaris. (Plate LXVIII. fig. 7.)
Granular nuclei of large size are seen on the walls of the cellated
spaces; these are most probably concerned in the secretion of the
vitreous humour. That these several cellated spaces communicate
with each other, seems proved by the fact that if the hyaloid mem-
brane be ruptured, the whole of the vitreous humour will gradually
escape through the aperture.
A layer of cells of large size, and of such extreme transparency ;
as to be discovered only with great difficulty, are described in the
"Physiological Anatomy" as situated on the hyaloid membrane,
between it and the retina : these have not fallen under the observation
of the writer.
The vitreous body, then, consists of the hyaloid membrane, cellated
fibrous structure, the zone of Zinn, and of the vitreous humour.
522 THE SOLIDS.
Through the centre of tms body a branch of the central artery of the
retina passes in early life, destined for the posterior part of the capsule
of the lens.
Crystalline Lens.
The cr-ystalline lens is composed of capsule and body.
The capsule is formed of a thin lamella of elastic tissue, much thicker
before than behind, but in all essential particulars similar to the poste-
rior elastic lamina of the cornea. The manner in which it is attached
to the hyaloid membrane has been already pointed out; it now remains
to observe that the cellated fibres of the vitreous body are also inserted
into its posterior part. It is perfectly closed on all sides, so that in
the adult condition of the eye neither vessels nor nerves pass through
it to the lens.
The body of the lens, transparent and jelly-like as it appears to the
unaided sight, is yet full of elaborate and elegant structure. It consists
of very many layers of concentric lamellae of flattened fibres, which
radiate from the centre, and are disposed in a parallel manner with
reference to each other; the fibres, however, have a more complicated
arrangement than this, as will be evident from what follows.
In the Mammalia in general, there are visible on the front surface
of the lens, when this has slightly lost its transparency, three radiating
grooves or lines, the points of which terminate at about one-third
from the border of the lens. On the opposite surface of the lens
there exist three similar lines, occupying an intermediate position.
From these lines the fibres pass from the one surface on to the other ;
thus a fibre which starts from the point of one of the lines in front,
passes over the border of the lens, advances midway between two
lines on the opposite surface, and is inserted in the angle of division
of those lines; another fibre starting from between two lines in front,
is lost on the extremity of a line situated posteriorly : the rest of the
fibres occupy positions intermediate to these. If, in the next place,
we bear in mind the fact that these lines, seen on the surface of the
lens, are but the edges of planes which pass through the centre of
the lens, affording points of divergence, and concourse for all the
fibres, deep as well as superficial, we shall readily comprehend what,
without this explanation, would have appeared an intricate arrange-
ment; and we shall perceive why it is that the lens, when hardened
in spirit, or boiled in water, is prone to separate into concentric lamellae,
and into three triangular segments. From the above arrangement it
ORGANS OF THE SENSES. 523
results, also, that all the fibres, whether superficial or deep-seated,
decrease in width as they approach the centre of the lens on either
surface, and also that the superficial are longer and larger than the
deeper seated. (See Plate LXVII. fig. 13.)
The edges of the fibres are most beautifully toothed and dovetailed
together, as was first pointed out by Sir David Brewster. This
toothing is best seen in the eye of fishes; it is also clearly manifest,
although on a smaller scale, in the fibres of the lens of most mammalia
and of man. (See Plate LXVII. fig. 10.)
On the surface of the lens beneath the capsule, and occupying the
space between these, a delicate epithelium exists, very similar to that
on the posterior elastic lamina. (See Plate ~L~XN\\\. fig. 10.) After
death, this space is occupied by a small quantity of fluid, the liquor
Morgagni.
Beneath this epithelium, again, other small oval granular cells are
encountered ; from these possibly the fibres of the lens take their
origin.
The lens is of less density externally than internally ; this, is also
one of the results of the peculiar form and arrangement of the fibres.
In the adult eye, the lens is entirely destitute of blood-vessels,
although during its development in the foetus it is copiously supplied
with them.
THE ORGAN OF HEARING.
Elaborate as is the organization of the ear, it yet presents less
to interest the microscopical anatomist, than many other of the
organs which enter into the composition of the human fabric. The
ear is divisible into three portions — the limits of each of which are
well defined — an external, a middle, and an internal: the external
portion is an apparatus for the collection of sound; the middle is
designed for its conveyance to the internal, or true and essential
division of the organ of hearing.
The External Ear.
The external ear consists of the expanded part or auricle, and the
external meatus.
The Auricle. — The auricle presents several eminences and depres-
sions, many of which have received distinct names; it is made up of
integument, cartilages, and fat; the integument is thin and delicate,
and is furnished with but few sebaceous glands; the cartilages are of
524 THE SOLIDS.
the fibrous kind, and are three in number — the larger forming the
pinna, being separated from that of the tragus and anti-tragus, by
grooves filled up with fibrous tissue ; lastly, the fat is situated chiefly
in the lobe of the ear. Ligamentous bands bind the auricle to the
bone, while its movements are effected, in part, by muscular fibres
which pass between the prominent parts of its constituent cartilages,
but mainly, by three small muscles of the striped variety, and each
of which, has received a distinct name.
The Auditory Canal. — The auditory canal consists of two parts —
a cartilaginous and an osseous ; the first is formed by the prolongation
inwards of the cartilages of the auricle; these form a tube, deficient
at the upper and back part, where the place of cartilage is supplied
by a fibrous membrane ; this tube is inserted into the auditory pro-
cess of the temporal bone ; the osseous part of this canal is formed
by the auditory process already alluded to ; this process in the adult
is nearly three-quarters of an inch long, and to its outer margin the
tympanum is attached, the bone being grooved for its reception: in
the fetus, the auditory process is a detached ring of bone, into which,
however, the tympanum is inserted.
The orifice of the meatus is defended by hairs, the bases of which
are in connexion with sebaceous glands; still further inwards, but
limited to the cartilaginous part of the passage, the ceruminous glands
are encountered: these have already been described.
According to some observers, muscular fibres exist in the external
meatus, which becomes shortened by their contraction.
The Middle Ear.
The middle ear consists of the tympanum, tympanic cavity, and
the ossicles with their muscles.
The tympanum, or tympanic membrane, is divisible into three
laminae — an external or cuticular, a middle or fibrous, and an internal
or ciliated ; the external is a continuation of the cuticle which lines
the external meatus, and may be separated as a distinct membrane :
the fibrous tissue, of which the internal lamina of the tympanum is
composed, is strong and dense, and is arranged in a radiated manner;
into this the handle of the malleus is inserted : the blood-vessels which
supply the tympanum pass along the handle of the above-named
bone, and follow the same radiated course as the fibres themselves ;
the inner and third lamina is composed of cells of ciliated epithelium,
similar to those lining the tympanic cavity.
ORGANS OF THE SENSES. 525
The tympanic cavity is lined by a fibrous membrane, divisible
into two layers; the fibres entering into the composition of one of
these, follow a longitudinal course, while those of the other layer are
circularly disposed; these fibres are, for the most part, nucleated, and
would appear to be of the elastic kind: in the longitudinal layer, the
fibres are disposed in bundles, and are possibly contractile: on the
surface of this membrane, and lining immediately the tympanic cavity,
is a layer of ciliated epithelium, continuous on the one hand with that
of the tympanic membrane ; and on the other, with that clothing the
interior surface of the Eustachian tube.
Posteriorly, the tympanic cavity exhibits the openings of the mastoid
cells; anteriorly, the orifice of the Eustachian tube may be noticed,
while the internal wall of the tympanum presents two orifices which
communicate with the internal ear: these are the fenestra ovalis, leading
into the vestibule; and the fenestra rotunda, opening into the cochlea.
The whole length of the tympanic cavity, is traversed by a chain
of three bones, united to each other by muscles of the striped kind;
one extremity of this chain is attached, as already noticed, to the
tympanum, while the other, formed by the base of the stapes, is in
connexion with the fenestra ovalis.
In the tympanic cavity of the ear of the sheep cells, containing
pigment, may very generally be observed; among these, I have
noticed the occurrence of numerous delicate transparent cells, similar
to those of the white substance of the brain and spinal marrow.
The Internal Ear or Labyrinth.
The internal ear, which is the essential portion of the organ of
hearing, consists of three parts: the vestibule, the semi-circular
canals, and the cochlea; these are cavities imbedded in the petrous
bone, communicating with the tympanic cavity on the one side, by the
fenestras ovalis and rotunda; and on the other, with the internal audit-
ory canal. The dense bone immediately surrounding these cavities is
termed the osseous labyrinth, in contra-distinction to the membranous
labyrinth contained within them. The description of the form, &c,
of the osseous labyrinth belongs rather to descriptive than to general
or microscopic anatomy, and therefore will not here be entered upon.
The osseous labyrinth contains a fluid which has been called the
perilymph, from its surrounding, though in the vestibule and semi-
circular canals only, a hollow membranous apparatus — the membran-
ous labyrinth, which itself contains a fluid, the endolymph.
526 THE SOLIDS.
The following account of the structure of the spiral lamina ; of the
cochlea ; the cochlear muscle ; the cochlear nerves ; the membran-
ous labyrinth ; the vestibular and auditory nerves, is copied from the
"Physiological Anatomy:"
Of the Structure of the Spiral Lamina of the Cochlea. — "We
shall term the two surfaces of this lamina, tympanic and vestibular,
as they regard, respectively, the tympanic or vestibular scala. The
osseous portion of the spiral lamina extends more than half way from
the modiolus towards the outer wall, and is perforated, as already
described, by a series of plexiform canals, for the transmission of the
cochlear nerves ; these canals, taken as a whole, lie close to the lower
or tympanic surface, and open at or near the margin of this zone.
The vestibular surface of the osseous zone presents, in about the
outer fifth of its extent, a remarkable covering, more resembling the
texture of cartilage than any thing else, but having a peculiar arrange-
ment, quite unlike any other with which we are acquainted. Being
uncertain respecting the office of this structure, we shall term it the
denticulate lamina (Plate LXIX. fig. 3), from a beautiful series of
teeth, forming its outer margin, which project far into the vestibular
scala, and in the first coil, terminate almost on a level with the
margin of the osseous zone, but more within this margin towards the
apex of the cochlea. They thus constitute a kind of second margin
to the osseous zone, on the vestibular side of the true margin, and
having a groove beneath them, which runs along the whole lamina
spiralis, in the vestibular scala, immediately above the true margin of
the osseous zone. The intervals between the teeth, are to be seen on
their upper surface, on their free edge, and also within this groove, so
that the teeth are wedge-shaped, and their upper and under surfaces,
traced from the free edge, recede. The free projecting part, or teeth
of the denticulate lamina, form less than a fourth of its entire breadth,
and in the remainder of its extent, it appears to rest on the osseous
zone ; seen from above, after the osseous zone has been rendered more
transparent by weak hydro-chloric acid, rows of clear lines may be
traced from the teeth at the convex edge, towards the opposite or
concave edge of the lamina These lines appear to be a structure
resembling that of the teeth themselves, and they are separated from
one another by rows of clear, highly refracting granules, which render
the intervals very distinct. These intervals are more or less sinuous
and irregularly branched.
ORGANS OF THE SENSES. 527
" The denticulate lamina, thus placed on the vestibular surface of
the osseous zone, is above, and at some distance from the plexus of
the cochlear nerves, which lies near its tympanic surface. The vesti-
bular surface of the osseous zone, including the denticulate lamina, is
convex, rising from the free series of teeth towards the modiolus.
"In the groove already mentioned, there is a series of elongated
bodies, not unlike columnar epithelium, in which the nuclei are
very faint.
" These bodies are thick and tubical at one end, and taper much
towards the other. They are united in a row, and it is possible they
may have some analogy to the club-shaped bodies of Jacob's mem-
brane. We can assign them no use.
"Continuous with the thin margin of the osseous zone is the mem-
branous zone. (Plate LXIX. Jig. 4.) This is a transparent glassy
lamina, having some resemblance to the elastic laminae of the cornea,
and the capsule of the lens. A narrow belt of it, next the osseous
zone, is smooth, and exhibits no internal structure, while, in the rest
of its width, it is marked by a number of very minute straight lines,
radiating outwards from the side of the modiolus. These lines are
very delicate at their commencement, become more strongly marked
in the middle, and are, again, fainter ere they cease, which they do at
a curved line on the opposite side. Beyond this, the membranous
zone is, again, clear and homogeneous, and receives the insertion of
the cochlearis muscle. The inner clear belt of the membranous zone
is little affected by acids; it seems hard and brittle. The middle or
pectinate portion is more flexible, and tears in the direction of the
lines. The outer clear belt is swollen, and partially destroyed by the
action of acetic acid. Along the inner clear belt, and on its tympanic
surface, runs a single, sometimes branched vessel, which would be
most correctly called a capacious capillary, as it resembles the capil-
laries in the texture of its wall, but exceeds them in size. It is the
only vessel supplied to the membranous zone, and seems to be thus
regularly placed, that it may not mar the perfection of the part as a
recipient and propagator of sonorous vibrations."
Of the Cochlearis Muscle. — "At its outer or convex margin, the
membranous zone is connected to the outer wall by a semi-transpa-
rent structure. This gelatinous-looking tissue was observed by
Breschet, and is, indeed, very obvious on opening the cochlea; but
we are not aware of any one having hinted at what we regard to be
its real nature. The outer wall of the cochlea presents a groove,
THE SOLIDS
ascending the entire coil, opposite the osseous zone of the lamina
spiralis, and formed principally by a rim of bone, which, in section,
looks like a spur, projecting from the tympanic margin of the groove,
the opposite margin being very slightly or not at all marked. This
groove diminishes in size towards the apex of the cochlea. It gives
attachment to the structure in question, by means of a firm dense film
of tissue, having a fibrous character, and the fibres of which run
lengthwise in the groove, and are intimately united to it, especially
along the projecting rim. From this cochlear ligament, the cochlearis
muscle passes to the margin of the membranous zone, filling the
groove and projecting into the canal, so as to assist in dividing the
tympanic and vestibular scalae from one another, and thus forming, in
fact, the most external or the muscular zone of the spiral laminae.
Thus the cochlear muscle is broad at its origin from the groove of
bone, and slopes above and below to the thin margin in which it ter-
minates, so that its section is triangular, and it presents three surfaces,
one towards the groove of bone, and one to each of the scalee. The
surface towards the vestibular scala is much wider than that towards
the tympanic scala, and presents, in a band running parallel to and
at a short distance from the margin of the membranous zone, a series
of arched vertical pillars with intervening recesses, much resembling
the arrangement of the musculi pectinati of the heart. (Plate LXIX.
fig. 5.) These lead to, and terminate in, the outer clear belt of the
membranous zone, which forms a kind of tendon to the muscle. This
entire arrangement is almost sufficient of itself to determine the mus-
cular nature of the structure. If its fibres were of the striped
variety, no doubt would remain : but its mass, evidently fibrous, is
loaded with nuclei, and filled with capillaries, following the direction
of the fibres, and in almost all respects it has the closest similarity to
the ciliary muscle of the eye.
"The capillaries of the ciliary muscle are derived from vessels
meandering over the walls of the scala before entering it, and those
from above and below do not anastomose across the line of attach-
ment of the membranous zone ; thus indicating that the continuation
of this zone enters as a plane of tendon into the interior of the muscle,
dividing it into two parts, and receiving the fibres in succession.
" The scalse of the cochlea are lined with a nucleated membrane, or
epithelium, which is very delicate, and easily detached, usually more
easily seen in the vestibular than in the tympanic scala, and in many
animals containing scattered pigment"
ORGANS OF THE SENSES. 529
Of the Cochlear Nerves. — " These enter from the internal auditory
meatus through the spirally arranged orifices at the base of the modiolus,
and turn over in succession into the canals hollowed in the osseous
zone of the spiral lamina, close to its tympanic surface. In this
distribution, the nervous bundles sub-divide and reunite again and
again, forming a plexus with elongated meshes, the general radiating
arrangement of which may be readily seen through the substance of
the bone when it has been steeped in diluted hydro-chloric acid.
(Plate LXIX. fig. 6.) Towards the border of the osseous zone, the
bundles of the plexus are smaller and more closely set, so as at length
almost to form a thin uniform layer of nervous tubules. Beyond the
border, and partially on, or in the inner transparent belt of the mem-
branous zone, these tubules arrange themselves more or less evidently
into small sets, which advance a short distance, and then terminate
much on the same level. These terminal sets of tubules are cone-
shaped, coming to a kind of point ere they cease. The white sub-
stance of Schwann exists in them throughout, but is thrown into
varicosities, and broken with extreme facility, and they are inter-
spersed with nuclei, so that it is very difficult to discover the precise
disposition of the individual tubules. They seem to cease, one after
another, thus causing the set to taper; and at least it appears certain
that evidence of loopings, such as have been described by some, is
wanting. In the cochlea of the bird, however, we have seen at one
end, a plexiform arrangement of nucleated fibres ending in loops; but
this is a peculiar structure.
"The capillaries of the osseous zone are most abundant on the
tympanic scala, in connexion with the nerves now mentioned, and form
loops near the margin, with here and there an inosculation with the
large marginal capillary already mentioned."
Of the Membranous Labyrinth. — " This has the same general
shape as the bony cavities in which it lies, but is considerably smaller,
so that the perilymph intervenes in some quantity, except where the
nerves passing to it confine it in close contact with the osseous wall.
Its vestibular portion consists of two sacs, viz: a principal one of
transversely oval figure, and compressed laterally, called the utriculus,
or common sinus, occupying the upper and back part of the cavity,
in contact with the fovea semi-elliptica, and beneath this a smaller
and more globular one, the sacculus, lying in the fovea hemispherica,
near the orifice of the vestibular scala of the cochlea, and probably-
communicating with the utriculus.
34
530 THE SOLIDS.
" The membranous semi-circular canals have the same names,
shape, and arrangement as the osseous canals which enclose them, but
are only a third of the diameter of the latter. As the osseous canals
open into the vestibule, so the membranous ones open at both ends
into the utriculus, there being, however, a constricted neck between
this sac and the ampullated extremity of each canal. The auditory
nerve sends branches to the utriculus, to the sacculus, and to the
ampulla of each membranous canal. These nerves enter the vesti-
bule by the minute apertures before described, and tie down, as it
were, both the utriculus and sacculus to the osseous wall at those
points, the membrane being much thicker and more rigid at those
parts. The branches to the ampulla of the superior vertical and the
horizontal semi-circular canals, enter the vestibule with the utricular
nerve, and then cross to their destinations, while that to the ampulla
of the posterior vertical canal, traverses the posterior wall of the
cavity, and opens directly into the ampulla.
" The wall of the membranous labyrinth is translucent, flexible, and
tough. When withdrawn from its bed and examined, it appears to
present three coats — an outer, middle, and internal. The outer is
loose, easily detached, somewhat flocculent, and contains more or less
colouring matter, disposed in irregular cells, exactly resembling those
figured at page 35, from the outer surface of the choroid coat of the
eye. We have not found a true epithelium on this surface. The
middle is the proper coat, and seems more allied to cartilage than
any other tissue; its limits are well marked, it is transparent, and
exhibits in parts, a longitudinal fibrillation; treated with acetic acid,
it presents numerous corpuscles or cell nuclei. Where it is thinnest,
it has a near resemblance to the hyaloid membrane of the eye. The
internal coat is composed of nucleated particles, closely opposed, and
but slightly adherent; the nuclei are often saucer-shaped, and when
seen edgeways have the uncommon appearance of a crescent. They
easily become detached, and fall into the endolymph. Minute arteries
and veins, derived chiefly from a branch of the basillar accompanying
the auditory nerve, enter the vestibule from the internal meatus, and
ramify on the exterior of the membranous labyrinth, apparently bathed
in the perilymph. A beautiful net- work of capillaries, forcibly remind-
ing the observer of that belonging to the retina, is spread out on
the outer surface, and in the substance of the proper coat. These
vessels have the simple homogeneous wall, interspersed here and there
with cell nuclei, that characterizes the capillary channels in many
ORGANS OF THE SENSES. 531
other situations. There is an abundant net-work of capillaries in the
interior of the utriculus and sacculus, about the terminal distribution
of the nerves, which evinces the activity of the functions of these
parts.
" The membranous labyrinth, or its simple representative, the audit-
ory sac, contains in all animals, either solid or pulverulent calcareous
matter in connexion with the termination of the vestibular nerves.
This has been called by Breschet otolith or ear-stone, when solid, as
in the osseous fishes, and otoconia or ear-powder, when in the form
of minute crystalline grains, as in Mammalia, birds, and reptiles ; but
the former term may be conveniently employed to designate both
varieties. In the Mammalia, including man, it is found accumulated
in small masses about the termination of the nerves, both in the
utriculus and sacculus, and we have found it also sparingly scattered
in the cells lining the ampullae and semi-circular canals. In the
vestibular sacs it appears to be entangled in a mesh of very delicate
branched fibrous tissue, in connexion with the wall, and it is most
probably held in place by cells within which, according to Krieger,*
its particles are deposited. It has a regular arrangement, and is not
free to change its place in the endolymph. Otolithes consist always
of carbonate of lime."
Of the Vestibular Nerves. — " In consequence of the thickness of
the wall of the membranous labyrinth where the nerves enter, and
the presence there of the calcareous and fibrous matter, it is not easy
to ascertain with certainty the precise manner in which the nerves
terminate. In the utricule and saccule, they appear to spread out
from one another as they enter, and then to pass, some to mingle
with the calcareous powder, others to radiate for a small extent on
the inner surface of the wall of the cavity, where they come into
connexion with a layer of dark and closely-set nucleated cells, and
presently lose their white substance. We have seen a fibrous film
on the inner surface of these parts, which we are disposed to consider
as formed, like the inner surface of the retina, by the union of the
axis-cylinders of the nerve tubes, but confirmatory observations are
required. Those that traverse the calcareous clusters have appeared
to us, in the most lucid views we have succeeded in obtaining, to
terminate by free, pointed extremities, without losing their white sub-
stance. In the frog this has been evident enough.
" The nervous twigs belonging to the semi-circular canals do not
* De OtolUHs. Berol, 1840.
532 THE SOLIDS.
seem to advance beyond the ampullae, in which they have a remark-
able distribution — entering them, as Steifensand has well shown, by a
transverse or forked groove, on their concave side, and which reaches
about a third round. Within this, the nerve projects so as to form a
sort of transverse bulge within the ampulla. Their precise termina-
tion can be best seen in the osseous fishes, and has been described
by Wagner to be loop-like. We believe we have seen this mode of
termination, though certainly never so plainly as the figure given by
this excellent author would indicate; and we may add that we have
found free extremities to the nerve tubes, as well as loopings, in the
ampullae of the cod. The difficulty in these cases of ascertaining
the exact truth arises from the curves formed by the nerve tubes in
proceeding to their destination, and which are liable to be mistaken
for terminal loopings."
Of the Auditory Nerves. — "At the bottom of the meatus, the
portio mollis divides into two branches, one to the vestibule and
semi-circular canals, the other to the cochlea.
" The vestibular nerve divides into three branches ; — the largest is
uppermost, and penetrates the depression which is immediately behind
the orifice of the aqueduct of Fallopius to be distributed to the
utriculus, and to the ampullae of the superior vertical and horizontal
semi-circular canals. The second branch of the vestibular nerve
is distributed to the sacculus; and the third to the posterior vertical
semi-circular canal.
"The cochlear nerve penetrates the funnel-shaped depression at
the bottom of the auditory canal, and. proceeds from it through the
numerous foramina, by which its wall is pierced in a spiral manner,
to the lamina spiralis of the cochlea.
"The mode of distribution of these nerves has been already
described.
"The labyrinth receives nerves from no other source but the portio
mollis, unless we suppose the portio intermedia to consist of filaments
from the facial which accompany the ramifications of that nerve into
that part of the ear."
ORGANS OF THE SENSES. 533
EYE.
[Little need be said with regard to the methods of studying the anatomy
of the eye, farther than the directions already given. The sclerotic and
successive lamina of the cornea, can only be well seen on careful dissection ;
for this purpose, fresh eyes are necessary, and the dissection should be
made under water. The arrangement and size of the tubes of the cornea,
may be seen by driving mercury or air into a slight puncture. A thin
section, dried and opened with needles under water, will also exhibit them.
Acetic acid is a valuable assistant in minute dissection of these structures.
The vessels of the choroid membrane and of the ciliary processes are
best observed after injection; a foetal subject will here offer the best chance
of success when the injection is made by the umbilical vein. To examine
the tunica Jacobi, Quain and Sharpey state that it may be raised from the
surface of the retina by injecting air or introducing mercury beneath it,
when under water. The retina should be examined in the freshest possible
state. Wagner recommends white rabbits as subjects; the pigmentary
matter of the choroid coat offering no obstacle to accurate observation. Dr.
Hannover, of Copenhagen, states that the vitreous body is best studied in the
eye of the horse, after having been hardened in chromic acid. In man, he
found the vitreous humour to be arranged, as it were, in arched slices or
wedges, the arches turned outwards, and the angles converging towards the
axis of the eye like the wedges of an orange. If the sections are horizon,
tal, they resemble the slices of an orange cut from pole to pole : if perpen-
dicular, they resemble one cut at right angles to the preceding direction.
This arrangement is more clearly seen in infants than in adults. Dr.
Hannover was unable to decide whether the membrane between these
segments is single and common to both, or whether each segment is
furnished with a membrane of its own.*
Plate LXXVIII., fig. 1, The terminal vessels in the cornea of the eye
of the pig.
" fig. 2, Cornea of viper, showing its vascularity.
" " fig. 3, Choroid coat of foetal eye.
" " fig. 4, Ciliary processes of the eye of an adult.]
* Dublin Quarterly Journal, May, 1848.
APPENDIX.
Pituitary Gland.
The pituitary body, inasmuch as it presents the usual characteristics
of glandular structures, would be more accurately denominated the
pituitary gland, a term which conveys its real nature.
The pituitary gland, in the absence of an excretory duct — unless
indeed the infundibular process attached to it is to be considered as
such — would appear to be allied to the vascular glands, while in some
other respects it resembles the ganglia of the sympathetic, which also
are glandular organs.
It consists of two lobes, an anterior and a posterior, which differ
from each other in size, colour, and consistence; the former is con-
siderably the larger of the two, is of a yellowish gray colour, and of
much firmness and density; while the latter is gray and soft, and
scarcely differs in consistence from the gray matter of the cerebrum.
As the two lobes differ in colour and consistence, so are they some-
what different in structure also; the anterior or denser lobe is made
up of numerous granular cells, very various in form and size, and
many of which are in some cases of very considerable dimensions;
these cells lie in meshes of fibrous tissue, which separate and parcel
them out, each of the larger cells occupying separately an entire
mesh. (Plate LXIX. fig. 8.) The posterior lobe differs from the
anterior in the smaller size of its cells, and the less amount of fibrous
tissue which enters into its composition.
The pituitary gland is connected with the brain by means of the
infundibulum, the small extremity of which is attached to the superior
concave surface of the gland, and is united principally to the posterior
lobe, which it also resembles in structure, containing very many
granular cells in its parietes.
This gland resembles a ganglion of the sympathetic in the large
size of its cells, and in the arrangement of its fibrous constituent ;
536 APPENDIX.
but differs from it in the irregular form of the cells, and in the absence,
so far as has been yet ascertained, of tubular nerve fibres.
Pineal Gland.
Notwithstanding the interest which exists in the minds of most
persons in reference to this body, and which has arisen in conse-
quence of the strange physiological speculations of which it has been
the subject, its structure yet does not appear to have been examined
with that amount of care which has now been bestowed upon most
of the other organs which enter into the constitution of the human
fabric; not, however, that its organization is uninteresting or difficult
to be understood ; for this, while it is complex and singular, yet admits
of easy determination.
The chief bulk of the pineal gland, is made up of innumerable
minute granular cells, which, when carefully examined in a perfectly
fresh subject, are seen to be of the caudate form, the rays of the cells
being exceedingly delicate and slender, and apt, therefore, to be
entirely overlooked.
Imbedded in this cellular matrix, and, for the most part, collected in
the centre of the organ, there may be noticed numerous particles of
stony hardness of various sizes, and mostly of a rounded form, and
the larger of which are plainly visible to the naked eye. Of these
bodies, I have never encountered any satisfactory description ; they
are not, as generally considered, mere inorganic and earthy particles,
but structures of a definite and complex organization, constituting an
essential element in the composition of the pineal gland. When
viewed with the half or quarter-inch object-glass, the larger of these
bear much resemblance to masses of fat, each being composed of
numerous distinct and aggregated lesser pieces, or particles which
reflect light strongly, and it is in this circumstance, as well as in their
large size, that the resemblance borne by these bodies to masses of
fat consists. (Plate LXIX. jig. 7.)
In the natural condition, these bodies are hard and brittle; after,
however, the application of dilute nitric acid, they become soft, the
earthy matter being dissolved away, and nothing remaining but their
animal constituent ; this, if the acid employed has not been too strong,
still retains, to a great extent, the size, form, and appearance of these
bodies, previous to its action, and will now readily be seen to exhibit
a cellular structure, a cell corresponding to each of the bright con-
stituent pieces above described. If, however, the acid employed be
APPENDIX. 537
somewhat stronger, these bodies undergo a singular change in form
and appearance, the cellated spaces become almost lost to view, and
these compound structures assume the characters of large and spher-
ical cells exhibiting numerous concentric lamellae. The earthy matter,
then, is contained in these cells or cellated spaces; the acid dissolves
this away, and the entire body becomes so soft, as to admit readily of
being torn to pieces with needles; in this state, its structure may be
easily determined, and is seen to consist of membranous elastic tissue.
These bodies originate in exceedingly small and bright circular
discs, which, when seen with the quarter-inch object-glass, are less in
size than the head of a pin; in these appear first, one, and, afterwards,
other divisions, indicating the compound and cellular character, which
they ultimately more completely exhibit.
The earthy matter entering into their composition consists of phos-
phate of lime, a small portion of phosphate of magnesia, and a trace
of carbonate of lime.
Minute sandy particles have been described connected with the
choroid plexuses, and that portion of the velum inter-positum which
invests the pineal gland ; whether these bodies are of the same nature
as those occurring in the gland itself, I am unable to say, not having
myself detected them in either of the above situations.
These bodies, which are almost peculiar to the human subject, are
stated not to occur in the pineal gland, until after the age of seven
years.
In addition to the above described essential elements of every fully
formed human pineal gland, I encountered on one occasion two large
round cells or bodies, containing dark nuclei of a compound charac-
ter; these appeared to be some modification of the sabulous bodies
already described.
The pineal gland is copiously supplied with blood-vessels, is trav-
ersed sparingly with delicate nerve tubules, and contains a small
quantity of an exceedingly slender form of fibrous tissue, which
possibly proceeds from the caudate cells already noticed.
The Pia Mater.
The pia mater, the vascular membrane of the brain, is composed
of fibrous tissue and blood-vessels ; over the surface of the brain and
its convolutions, this membrane is delicate and highly vascular, while
over the spinal marrow, it is thicker and less freely supplied with
vessels.
533 APPENDIX.
In the ventricles, this membrane forms the choroid plexuses and
velum inter-positum ; in the former, it is thrown up into numerous
processes or villi, each of which is furnished with a large looped
blood-vessel, and its outer surface, like the villi of the intestines, is
clad with a very evident epithelium. (Plate LXIX. fig. 9.)
This epithelium, according to many observers, -is of the ciliated
kind; the cells composing it, are polygonal somewhat flattened, and,
as Henle* long since noticed, furnished at their angles with spinous
processes; these are only to be seen in perfectly fresh subjects, and it
is probable that in some cases, they have been mistaken for cilia; not,
however, since the fact has been attested by several witnesses, that I
would deny the existence of ciliary processes on the cells of this
epithelium.
. The Pacchionian Glands.
The Pacchionian Glands are found among the vessels of the pia
mater on the edges of the cerebral hemispheres, and are described as
granulations composed of an albuminous material; they push before
them the arachnoid membrane, project into the longitudinal sinus,
and, in cases, even occasion absorption of the parietal bones, lying
imbedded in little pits or recesses. They are stated not to occur in
early life, and they are frequently absent in the adult.
I have encountered on the surface of different portions of the pia
mater, usually near to the sulci of the convolutions, little masses or
bodies of two forms, apparently very distinct ; in the first, these were
opaque and whitish, and consisted of a capsule of fibrous tissue,
enclosing a number of minute granular cells; in the second, the
masses appeared to lie free among the vessels of the pia mater, and
each broke up readily on being touched into several other smaller
granulations of the same character: these, examined with the micro-
scope, were seen to be made up of numerous dark-looking bodies,
very irregular in form and size, and which appeared to be of a fatty
nature.
Observations on the Development of the Fat Vesicle.-f
"When the difficulty of determining the exact structure of the fat
vesicle is considered — a difficulty arising from the extreme tenuity
of its cell- wall, and the opacity of its contents — it is scarcely surpris-
* Anat. Gen. t. i. p. 233.
f By the Author. — Lancet, January 20th, 1849.
APPENDIX. 539
ing that we should yet be without any consistent account of the
modes of development and growth of the fat vesicle.
"This hiatus in the structural history of that peculiar animal tissue,
fat, the present brief remarks are intended in some measure to fill up.
"When the little fatty masses which are met with so abundantly in
the neck, in the neighbourhood of the thyroid and thymus glands, as
also in some other situations in a foetus nearly or quite arrived at
maturity, are examined, it will be observed, by the use of a lens only,
that these masses are each composed of a number of distinct and
opaque bodies of various sizes, presenting a smooth outline, having a
more or less rounded or oval form, and held loosely together by fibro-
cellular tissue, the extension of which forms the envelope which
invests each of these bodies. It will also be further noticed that each
mass of fat is supplied with one or more blood-vessels, and that these
break up into numerous lesser branches, one of which goes to each
of the previously-described bodies, being conveyed to it by the con-
necting fibrous tissue; and that, having reached this body, it undergoes
a further sub-division, the branches extending over its entire surface.
"In continuation of these observations, it will be remarked, that
each of these peculiar bodies bears a close resemblance in its general
aspect, to a lobe of a sebaceous gland — a resemblance, which, as will
be seen almost immediately, extends even to its internal structure.
"If a number of these bodies be torn into fragments with fine
needles, and be examined with a half or quarter-inch object-glass, it
will be observed that the cavities of some of them are filled with
cells of a large size, and which again are occupied with numerous
globules of various dimensions, presenting many of the characters
of oil globules, but being of greater consistence. (Plate LXIX.
Jig. 10.) These cells, save by their somewhat larger size, it is impos-
sible to distinguish from the perfect cells of sebaceous glands; so
complete indeed is this resemblance, that at first sight I did not
hesitate to regard them as belonging to some sebaceous gland, and
which I was much astonished to encounter in such a situation.
Others of these peculiar bodies, which may be termed 'fat cysts,'
contain a mixture, in variable proportions, of these compound cells and
of free globules, which, however, it is to be observed, are generally of
larger size than those contained within the compound or parent cells.
Lastly, others of these bodies enclose no compound cells, but are filled
with globules of still larger size. (Plate h~X.lX.Jig 11.)
"Now, the curious part of this history is, that it is these globules
540 APPENDIX.
which go on increasing in size, and, bursting the envelopes which
contain them, ultimately become what are ordinarily regarded as the
true fat vesicles.
"In the article Fat, in an early number of the 'Microscopic
Anatomy,' I noticed the fact, that the fat vesicles of children are not
so large as those of the adult; this fact it then appeared to me had an
evident relation to the growth of the fat vesicle, and it suggested the
idea that the fat corpuscle was of very slow growth, not attaining its
full dimensions until near the adult age ; and that it was permanent in
its character, enduring throughout life. This idea gathers increased
weight, and, indeed its correctness is rendered almost certain, by
the additional observations just cited on the development and growth
of the fat vesicle.
"It would appear, therefore, taking into consideration all the fore-
going particulars, that the principal development of fat vesicles takes
place in the advanced fetus, and in the early years of life (for I now
remember having met with 'fat cysts' in the great omentum of
children of five and six years of age, although at the time of observ-
ing them I did not know their nature and meaning), that what are
usually regarded as the true fat vesicles or cells, are first contained in
parent cells, and lastly, that they are slow in their growth, and
persistent throughout life.
"I infer also further, from the foregoing facts, that the ordinary fat
vesicles are incapable of acting as parent cells and of reproducing
their like; an inference which might be fairly entertained on other
grounds, viz: the difficulty, not to say impossibility, of detecting
nuclei in them, and the absence of those granules among their contents
which are so characteristic of true cells, and which there is so much
reason to believe are the real germs of the future generations of cells.
"From comparative observations it would appear that the develop-
ment and growth of fat proceed at different rates in different localities
of the same body, it being more advanced in one situation than in
another; and also in the same parts in different children of the same
age; so that an exactly similar condition of things to that which I have
described as existing in the masses of fat which occur in the region
of the neck in the mature fetus, must not in all cases be looked for.
" The structural resemblance which I have shown to exist between
fat cells in an early condition of their development, and the cells of
sebaceous glands is most interesting, the latter appearing to be, in fact,
simply fat in a rudimentary and imperfect state of its development."
APPENDIX. 54 1
On the Structure and Formation of the Nails.
Since the publication of the article contained in this work on the
structure of nail, some further observations by Mr. Raine}r, on the
same subject, have appeared; the more important of these are con-
tained in the following extracts :*
"The object of this paper is to show that the nails consist of at least two distinct
structures; one proper to them, the horny structure, and the other the cuticular one;
and also, that their matrix possesses one set of vessels expressly for the secretion
of the horny part of the nail, and another set for the formation of the cuticular por-
tion; and that besides these, there are other vessels, differing in their characters and
arrangement from the preceding, and probably intended to furnish a material, inter-
mediate in some of its properties between horn and cuticle, and destined to blend
these together, and thus to preserve their union during the growth and protrusion
of the nails. However far this idea may be correct, the anatomical fact of there
being these three different arrangements of vessels is indisputable."
Structure of the Nails.
"If a thin vertical section be made length ways through a finger-nail from its poste-
rior to its anterior or free margin, the external or dorsal surface of that portion of it
which was lodged in the groove between the matrix and the semi-lunar fold of skin
projecting from the dorsum of the finger, is seen covered by a thin layer of cuticle,
which extends backwards as far as its posterior border, which is generally jagged and
uneven, and forwards upon its dorsum. This portion of cuticle is immediately con-
tinuous with that overhanging the root of the nail, and although it is not inseparably
blended with its horny substance, yet it is sufficiently adherent to be carried forward
with it during its growth, and to remain intimately attached to its dorsal surface until
it is worn off by friction or some other mechanical cause. The palmar surface, near
to its free border, is also seen covered by cuticle, which in like manner divides into
two parts, the one becoming continuous with the cuticle covering the end of the
finger; the other passing backwards along the palmar surface of the nail as far as
the lunula, where it imperceptibly terminates. This portion of cuticle gradually
diminishes in thickness as it extends backwards, and is more intimately connected
with the horny part of the nail than was the cuticle on its dorsal surface. Between
these layers of cuticle the proper or horny matter of the nail can be distinguished,
presenting fine, nearly parallel, and generally semi-elliptical lines, with their con-
cavity looking in different directions in different parts of the same section, and also a
multitude of darkish-looking corpuscles, when viewed by transmitted light, of various
forms and sizes. These compose the substance of the horn of the nail, and the lines
are the cut edges of the laminas of which it is made up. The horny part of the nail
does not increase in thickness after it has extended beyond the lunula, the apparent
* "On the Structure and Formation of the Nails of the Fingers and Toes." By G.
Rainey, Esq., M. R. C.L.— Transactions of the Microscopical Society, March, 1849.
542 APPENDIX.
increase of the nail anterior to this point being derived from the cuticle formed upon
the anterior part of the matrix."
The Matrix of the Nail.
"A mere inspection, even in the living subject, of the parts situated beneath the
nail, is, in consequence of its transparency, sufficient to give a general idea of the
relative vascularity of the various parts of its matrix The upper part of the matrix
is seen to present a pale, semi-lunar space, called the lunula. The greater part of the
lunula is concealed by the semi-lunar fold of integument which projects over it; but
extending a little below this fold, the lower portion of the lunula is visible, presenting
a curved border, with its convexity looking downwards. Immediately below the
lunula, and circumscribing its inferior limit, the matrix has a reddish colour, which
gradually becomes fainter towards the free margin of the nail, but which deepens
considerably where the nail becomes detached from the integument.
"When the matrix is fully injected and the nail removed, the part corresponding
to the lunula presents several rows of convoluted capillaries : the individual convo-
lutions have different degrees of complexity, from a simple loop (a little twisted
round itself,) to a complex tuft of vessels. These rows have their direction from
above to below ; they are all slightly curved, being concave towards the median line
of each nail, and the most external ones are nearly parallel with its lateral margins.
These, being the vessels which secrete the horny part of the nail, may be called the
horn-vessels. Superiorly these vessels are separated from the rich plexus on the fold
of integument which overhangs the nail, by a fibrous and almost non-vascular groove,
in which the free border of the nail was lodged, and where the cuticle covering its
root terminates. A few vessels, however, pass across this groove from the horn-
vessels to the plexus just mentioned. Inferiorly the horn- vessels communicate with
quite a different arrangement of capillaries, which run in a more straight course, and
are much more crowded together than the horn-vessels. 'These vessels run nearly
parallel with one another, in a direction from behind forwards, and being very
near together, render this the most vascular part of the matrix, and produce that
redness immediately below the lunula upon which the form and degree of dis-
tinctness of its lower border is dependent. Just below these vessels the surface of
the matrix begins to be raised into numerous plications or folds, passing directly for-
wards, and increasing in depth as they approach the free extremity of the nail, where
they become continuous with the raised lines observable on the ends of the fingers.
These plicae consist each of a fold of basement membrane, enclosing a series of loops
of vessels. At first these loops are small and simple, but they become larger and
more complex, as they advance towards the end of the finger, where they are con-
tinued from the ridges of the matrix of the nail into those of the skin ofthe finger,
in which they are generally very -complex. When the nails are in situ, these ridges
are received into corresponding grooves in their inferior surface. Near the part of the
matrix where the plicae commence, several distinct circular or oval openings are
sometimes seen passing for some depth beyond the surface, and appearing like fol-
licles or lacunae. These are frequently closed by the opposition of the adjacent
plicae, and thus their presence is rendered doubtful, but they can be seen very dis-
tinctly either when some of the material which they contain has been recently removed,
or still remains within them in the form of whitish, globular masses. The situation
APPENDIX. 543
of these lacunae, where the openings themselves are not apparent, can be dis-
tinguished by the plexus of capillaries in their vicinity, in the areola; of which their
openings are situated."
On the Ganglionic Character of the Arachnoid Membrane.
The following extracts contain the more important portions of Mr.
Rainey's observations "on the Ganglionic Character of the Arach-
noid Membrane of the Brain and Spinal Marrow : " * •
" The first idea which suggested to me the resemblance of the arachnoid to the
sympathetic, was from the examination of a piece of the former taken from the infe-
rior and lateral part of the medulla oblongata, when I observed, at the meeting of
two of the chords situated between the arachnoid and pia mater (called by Magendie
'Tissu Cellulo-vasculaire sub-Arachnoid'), a triangular body of the form and general
appearance of the ganglion, very similar to such as I had seen in small animals.
" This resemblance appeared more striking on observing a branch going from the
chord connected with this body to the arachnoid membrane, along which it ran for a
considerable distance, dividing and sub-dividing in its course, in the manner of a
nerve ; the successive sub-divisions becoming more and more minute, and at the same
time interlacing and enclosing small areola; filled with corpuscular matter. These
corpuscles were so blended with the ultimate filaments of this chord as to render
indistinct their exact mode, of termination.
" Such was the connexion of one extremity of one of these chords. The next
point to be determined was the structure to which the other extremity of the same
chord had been attached. As, in this case, it had been separated from its connexion,
this could only be ascertained by examining similar chords in other portions of mem-
brane. This examination being made, I found that the end in question terminated
either on an artery or on a cerebro-spinal nerve. In the former case, a chord, as soon
as it comes in contact with an artery, divides into branches which ramify upon it, and
run along its external coat, just as, to all appearance, the branches of the solar
plexus do on the small arteries supplying the viscera in the abdomen. If the cerebral
artery be rather large, and situated between the arachnoid and pia mater, some of the
branches going from a chord form upon it a plexus, and others proceed onwards to
the vessels of the pia mater.
" In some instances a chord passes from an artery to the arachnoid without dividing
in its course, as just described ; but more frequently, on approaching tho latter,
it sends off three or four large branches, which pass to different parts of the mem-
brane, and ramify in it, as before explained; however, sometimes one of these
branches either itself expands into a large dense plexus, or joins other branches to
form one, from which plexus two, three, or more chords pass into the substance of
the arachnoid. The shape of these plexuses is either square or triangular, according
to the number of branches which join them, and the number they give off. Besides
consisting of interlacing fibres, they also contain corpuscular matter.
" The arachnoidal extremity of some of the chords connecting the vessels with the
* Medico- Chirurgical Transactions, 1846.
544 APPENDIX.
arachnoid of the cauda equina expands, close to the membrane, into a large oblong
and rather oval bulb, the axis of which is occupied by a continuation of the chord,
extremely convoluted, and bent upon itself; while, inferiorly, its fibres are blended
with those of the membrane.
" The chords which pass from the vessels of the pia mater, at the upper portion of
the brain to the arachnoid, terminate in the latter by fibres having a stellate arrange-
ment. There are also some large triangular plexuses like those at the base of the
brain, from which branches descend between the convolutions to the vessels within
the sulci.
" In the lower animals, as in the sheep, in which the cerebral convolutions are
small, the stellate fibres are the best seen. They can even be distinguished by the
naked eye, appearing like minute opaque points. At their centre, the fibres of which
they are composed, seem to be blended into an irregular confused mass, from which
other fibres radiate, and lose themselves in the cerebral surface of the arachnoid.
Some fibres go from one stellate body to another, and others can be traced into the
coats of the vessels : these latter are by no means numerous. Branches also descend
(still having somewhat the stellate disposition) between the convolutions to the
deep-seated vessels; these filaments are much more numerous upon some vessels
than upon others, and they do not appear to extend so far as the capillaries, no fibres
of any kind being visible upon this system of vessels.
" It appears, from what has been stated, that the disposition of the ramifying fila-
ments of the arachnoidal chords, and the form and size of the gangliform plexuses
connected with them, bear some proportion to the number and size of the vessels in
their vicinity. Hence, about the base of the brain, where the branches of the arteries
are large, the plexuses are also large, and of an irregular shape, while oh its upper
surface, where the vessels are comparatively small, and more equal in size, and have
a more uniform distribution, the plexuses are also smaller, more numerous, and more
regular in their shape and volume.
" Besides the plexuses situated in the course of the chords of the arachnoid, there
are others which are more intimately connected with its cerebral surface, and which,
in some situations, appear to compose the entire thickness of the membrane.
" In these plexuses, the filaments interlace very much in the same manner as the
nerves do in the plexuses of the cerebro-spinal and sympathetic systems. A chord,
for instance, when traced into one of them, will be observed to break up into its com-
ponent filaments, the adjoining bundles of which interlace, yielding to one another
one or more bundles, and the chords which emerge from the plexuses deriving their
component filaments from different bundles: these bundles and their component
threads, during their interlacing, will be seen to preserve their individuality.
" When a chord going from the arachnoid, terminates on a cerebral nerve, it divides
in the same manner as an artery, some filaments ascending and others descending
along with the nerve tubules. In some instances this extremity terminates in a sort
of membranous expansion, which encloses several nerve tubules."
Mr. Rainey, in the next place, enters upon the consideration of the nature of the
above-described apparatus of ramifying chords and plexuses, and arrives at the con-
elusion, derived from their relations and intimate structure, that they are composed
essentially of gelatinous or sympathetic nerve filaments.
APPENDIX. 015
"In the chords of the arachnoid (he writes) I could distinguish three different
kinds of filaments, all which exist in the branches of the sympathetic.
"One species, generally considered the most characteristic, is the nuclear fibre
described by Henle ; it is a flat, clear fibre, with oval, nearly equi-distant nuclei, and
each having its long axis corresponding to that of the fibre. I have found these
fibres in the arachnoid, but they are very rare. I have seen such going from the
arachnoid to the coat of the internal carotid, the trunks being blended with the mem-
brane, and the branches connected with the artery. I also found, that as the fibres
branch off from these trunks, and intermix with others, they lost their nuclei, became
more pale and clear, and differed in no respect whatever from the other fibres of the
membrane. Besides, I have seen these fibres in other parts of the membrane, and
they exist chiefly on the exterior of the larger chords. This species of fibre I have
also found to be very uncommon in the smaller branches of the nerves confessedly
sympathetic, especially in those most remote from the ganglia and larger trunks.
The next kind of fibre is one consisting of bundles, for the most part rather smaller
than nerve tubules, of very minute wavy filaments, intermixed with small particles of
granular matter, having no definite form, size, or position in respect to the filaments.
Some of the chords of the arachnoid are made up entirely of fibres of this description;
in others they exist chiefly on their surface, being most abundant near their attach-
ment to the arachnoid, upon which they are continued. This kind of fibre exists
abundantly in all the branches of the nerves undoubtedly sympathetic; and also,
more or less, in those connected with the ganglia. The third kind of fibre occurs in
the form of roundish, though sometimes flat chords, composed of extremely minute
wavy filaments, either collected or not into bundles, but apparently interwoven some-
what together, so that, generally, a filament of only an inconsiderable length will
admit of being detached mechanically from the rest, and, when thus separated, its
breadth is very unequal, and its contour ill-defined. These filaments are often totally
destitute of granular matter.
"This last species of fibre is very common among the chords composing the plex-
uses of the arachnoid ; it is also sometimes situated in the centre of the larger ones,
surrounded by the second species of fibre; this can be detached mechanically, and
exhibited separately under the microscope.
"In the nerves obviously sympathetic, this kind of fibre exists in considerable
abundance in those branches of the solar and other plexuses which are most remote
from the ganglia.
"Thus far my observations have been confined to the structure of the fibres of the
arachnoid, and their supposed use. I will now consider the corpuscular or ganglionic
part of this membrane. Some of the plexuses on its cerebral surface have the inter-
stices formed by their interlacing fibres, completely filled up with small roundish
corpuscles, about the size of blood-discs ; while, in others, these fibres are covered
with irregularly-oval masses of them. On this surface, also, in various situations,
there are well-defined round or oval bodies, having in their centre a granular nucleus
surrounded by fibrous tissue, intermixed with more or less corpuscular matter.
Some of these bodies are connected to the fibres of the arachnoid by a yery fine
thread, others are situated at the conflux of two or more fibrous chords, and their
diameter varies from that of two to seven blood corpuscles. They are generally
solitary and not numerous; but as they have been present iii the arachnoid of every
human subject which I have examined (a number exceeding twenty), they cannot be
35 '
546 APPENDIX
regarded as accidental or adventitious. At present I cannot decide as to their nature
or office, not having seen any thing which they exactly resemble in other parts of the
body; at any rate, they look more like small ganglia than any thing else I have seen.
" Besides these corpuscles, which, as before stated, exist on the cerebral surface of
the arachnoid, I have met with some of a very different character, situated in its sub-
stance, though nearer to the cranial than to the cerebral surface. The most ordinary
appearance which these present, when seen by transmitted light, is that of a section
of an urinary calculus made through its centre, appearing, like it, to be made up of
concentric layers. When viewed by reflected light, these bodies seem to be vesicu-
lar, and filled with fluid, the quantity of which appears to diminish as the number of
layers increases, so that those in which the laminae have extended as far as the
centre, are almost flat. Although the most frequent form of these bodies is circular,
yet some are oval ; occasionally they are connected with a fibre of the arachnoid, in
such a manner as to resemble small Pascinian corpuscles. One remarkable fact con-
nected with these bodies is, that they occur in the arachnoid of almost every subject
which I have had an opportunity of examining, and that no part of the membrane is
exempt from them ; generally they are solitary, and very sparingly distributed ; but
sometimes they are in clusters. I have found them in the internal Pacchionian
glands mixed with granular matter, and the same kind of fibre as exists in most parts
of the arachnoid membrane. Their diameter varies from 75,000 to 39.800ths of an
inch. I have observed on some parts of the arachnoid, in the vicinity of a cluster of
these bodies, cavities of a similar shape and size, from which the corpuscles them-
selves appear to have been dislodged. From this circumstance, as well as from the
general aspect of these bodies, they seem to me either to be structures altogether
adventitious, or the result of an abnormal deposition in diseased corpuscles. The
tendency which they may be observed to have to coalesce when several smaller ones
occur together, evident by the obliteration of those portions which seem pressed
against one another, and the union of the remote segments to form a single outline
enclosing an area whose figure clearly indicates the number of corpuscles which have
united to form it, proves them to be something more than mere earthy deposits, such
as are sometimes found in the choroid plexuses, or even than mere scrofulous tuber-
cles. Vogel has found bodies similar to these in the choroid plexuses; in these, and
in the pia mater, Dr. E. Harless has also seen them, and given a very minute account
of their structure in a number of Miiller's Archives, 1845. This author seems to think
that their seat is in the arteries, and that they are somewhat allied to ossification of
these structures; but their occurrence in all parts of the arachnoid, in some of which
there are nrobably no vessels, is opposed to this view."
Mr. Rainey regards the corpuscles constituting the epithelium of the choroid plex
uses as ganglionary, and details his reasons for this opinion; these, however, canno*
be admitted to be decisive on this point.
"As respects the supply of vessels and cerebro-spinal nerves to the arachnoid, I
may observe, that the arteries are few, but rather large, almost sufficiently so to
receive a small injection tube; (I have preparations of these;) and that cerebro-spinal
nerves may be traced into its visceral portion, and, with the microscope, their tubules
can be seen running along with the arachnoid fibres, into which they appear, from the
gradual loss of their tubular contents, to degenerate."
APPENDIX. 547
Structure of the Striped Muscular Fibrilla.
At page 358, doubts were expressed as to the correctness of the
view entertained by Drs. Carpenter and Sharpey, in reference to the
structure of the striped muscular fibrilla. At that period, the author
had not seen any of Mr. Lealand's preparations, on the examination
of which, the above-named gentlemen founded their opinion; he has
since, however, been favoured by Dr. Carpenter with the examination
of his own specimen, and this would certainly appear to bear out
fully their opinion of its cellular constitution.
Structure of the Bulb of the Hair.
Further opportunities of examination have satisfied the author that
the vesicle which he has described as forming a portion of the bulb
of the hair has no existence, and that this rests immediately upon a
compound vascular and nervous papilla.
The Synovial Fringes.
The synovial fringes consist of branched and elongated threads or
filaments, which taper to a point, and each of which is supplied with
one or more, according to its size, contorted and looped blood-vessels;
these, however, do not reach the whole length of each thread, but
terminate at one-third or one-half its length. It is in the termina-
tions of these filaments, according to the observations of Mr. Rainey,
that those cartilage-like bodies sometimes found loose in the joints,
especially the knee-joint, are first formed. The threads or filaments of
which the synovial fringes are constituted are of such length and so
much branched, that they might, at first sight, be mistaken for those
of some conferva of the genus Cladophora.
On the Anatomy of the Sudoriparous Organs.
Mr. Rainey* describes the duct of the sudoriparous glands as con-
sisting of two distinct portions, an epidermic and dermic.
The epidermic portion is of a conical form, the base being directed
towards the surface, and the apex situated in the midst of the cells
which form the deep layer of the epidermis; it is constituted of cells
which are flattened and elongated, and the long axes of which are
"On the Minute Anatomy of the Sudoriparous Organs." By G. Rainey. — Royal
Med. and Chirur. Society. See Lancet, 1849.
548 APPENDIX.
disposed in the direction of the length of this portion of the duct :
below, near its termination, the cells are thicker and less flattened.
The dermic portion of the duct is also of a somewhat conical shape,
its base being in like manner directed upwards, and its parietes being
continuous with the basement membrane of the dermis ; this portion,
therefore, is of a totally different structure from the former; it is
described by Mr. Rainey as being lined by a layer of epidermic scales,
which get gradually indistinct towards the gland, and its upper or
expanded part as receiving the termination of the epidermic division
of the duct.
This description of the duct of the sudoriparous gland, so far as I
have been able to follow it, would appear to be in its main particular
correct, it consisting, as stated, of two portions, an epidermic and a
dermic ; the former is scarcely to be regarded, however, as any thing
more than an appendage to the dermic part, which is the true duct, it
being little more than a definite channel through the epidermis.
It seems to me, however, to be incorrect to describe the epidermic
portion of the duct as commencing in the deep layer of the epidermis;
it extends beyond and far deeper than this, for it lines the whole length
of the true duct, and this not merely with loosely aggregated cells,
but these are so united together as to form a distinct tubular mem-
brane, which by maceration may be exhibited as such (see Plate
XXIII. fig. 2); the epidermic cells become, in fact, continuous with
those of the sudoriparous gland itself.
Mr. Rainey has noticed the fact that the secretion of the sudoripa-
rous glands in the palms of the hands and soles of the feet, where the
sebaceous glands are entirely wanting, is of a greasy character; from
this circumstance he draws the conclusion that these glands secrete
both sweat and sebaceous matter, the former in their more active
state, the latter in their less active condition.
It is only in the hands and feet, where the epidermis is thick, that
the epidermic portion of the sudoriparous duct assumes importance.
INDEX.
PAGE
437
Adams, Mr. On the calculi of the prostate
Addison, Dr. His belief in the existence of a
nucleus in the red blood disc . . .93
Views on the structure of the red blood cor-
puscle . 94
Observations on the white corpuscles of the
blood 103
Further observations on the same . 106. Ill
His opinion that milk, mucus, and bile are the
visible fluid results of the first dissolution of
the cells .....
His opinion that the white corpuscles are the
foundations of the tissues and the special
secreting cells. ....
On the presence in increased quantities of the
white corpuscles in the hard and red basis
of boils and pimples, and in the skin in scar-
latina, ......
His opinion that mucous and pus globules are
altered colourless blood corpuscles
His opinion that out of the white corpuscles
of the blood, all other corpuscles met with
in the body are formed
On the action of liq. potass, on pus
LOG
107
On epithelial scales in the air cells of the lungs 397
On tuburcles of the lungs
Aggregated or Peyer's glands
Albinoes, state of pigmentary cells in
Hair of .
Albinus. The first describer of the nail
Alcohol and Water ....
Allen, microscope of ...
Alpaco, blood of ... .
Alumina, acetate of
Ancell. On the increased quantities of white
corpuscles in the blood in inflammatory
affections .....
Andral and Gavarret. On the mammillated
appearance of the red blood discs .
Important researches on the pathology of the
bloud .....
Andral, A. G. Camus, and Lacroix. On the
Pacinian bodies
Annelidie, blood of
Arachnoid Membrane
Ganglionary, character of .
Area Vasculosa
Arteries, injection of .
Asphaltum Cement
Axilla. New tubular gland in.
Axillary glands. Structure of
138
. 386
80
. 543
543
. 130
39
. 49
Plate lvii.
130
Baly. His opinion that the white globules are
red blood corpuscles in process of formation 112
Bariy, Dr. His belief in the existence of a
nucleus in the human red blood discs . 93
Views on the structure of the red blood cor-
puscle . . . . . .94
Views on the white blood corpuscle . 107
His opinion that the tissues are formed by
direct apposition of the blood corpuscles . 107
His discovery of spermatozoa on the ovary 233
Bat. Hair of . . . .304
Bear. Spermatozoa of 224
Beclard. On the disappearance of the fat vesicle 261
Becquerel and Rodier. Researches on the blood 158
Berzelius. Analysis of healthy in ine . . 246
Bidder. On the peripheral distribution of the
gelatinous nerve filaments . . 3S2
On the structure of the kidney . . 450
On the structure of the Malpighian body . 451
Bile 042
Epithelium in . 243
Cell-like bodies in ... 243
Corpuscles of liver in 243
Meconium ..... 243
Birds, fat of . . . . 255
Malpighian bodies of . . . 464
Bisohoff. His discovery of living spermatozoa
in the rabbit eight days after intercourse 227
His discovery of spermatozoa on the ovary itself 233
On the structure of the kidney . . 450
Blood . . . . . ,79
Definition of . . . . .80
Red blood . . . , .80
Colourless blood .... 80
Composition of . . . . .80
Coagulation of without the body . . 80
Death of . . . . . .80
Quantity of in the body ... 80
Blood of annelidie . . . .80
Clot 81
Coagulation of blood within the vessels after
death 86
Motling of . . . .85
Fluid state of after death . . ' . 87
Globules of . . . . .88
Red • . . . . .89
White ..... 100
Venous and arterial blood . . . 134
Causes of inflammation . . . 140
Exciting cause ..... 140
Proximate causes .... 140
Pathology of blood .... 142
Blood in the menstrual fluid . . 160
Transfusion of blood .... 160
Importance of a microscopic examination of
the blood in criminal cases . . 164
Corpuscles, preservation of . . 170
4i size of . . . .79
Examination of . . . . , 169
Stains, how detected by the microscope . 164
Bone. Structure of .... 317
Cancellous structure . 317
Lamellie of . . . , 317
Medullary cells of . . . . 317
Communications of ... .. 317
Contents of . . . . . 318
Canalicular structure of . 318
Haversian canals of . . . . 318
Contents of ditto .... 319
Arterial and venous Haversian canals . 319
Lamellte ... ... 319
Number and arrangement of ditto . . 320
Structure of ditto . . . .320
Bone cells . . . . .321
Differences of opinion as to nature of . . 321
Form of . . . .321
550
INDEX.
PAGE
. 322
32i
. 329
330
.3-22
32-2*
. 323
324
. 324
325
. 325
326
. 330
331
. 332
332
. 334
Bone. Canaliculi of ...
Size of bone cells in different animals
Development of ditto ....
Comparison of to stellate pigment
Marrow of bones ....
Periosteum of ditto ....
Vessels of ditto .....
Nerves of d:tto ....
Growth of ditto .....
Development of ditto
Intra-membraxious term of ossification
lntra-cartdaginous form of ditto
Formation of medullary cavity
Ditto of medullary ceils
Ditto of Haversian canals
Accidental ossification
To make sections of
Bowerbank, Mr. On the size of the human
blood disc . . . .
Bowman, Mr. On the lining membrane of the
F;diopiaii tubes
His doubts as to the existence of a lobular bil-
iary plexus ....
His opinion that the series of secreting cells
represent the continuance of the biliary-
ducts
On the ciliated epithelium at the neck of the
Malpighian dilatations
His opinion that the afferent vessel of the
Malpighian tuft pierces the ddated extremity
of tne tube .... 444. 451
On the termination of the renal artery on the
Malpighian bodies . . . '146
On tiie uses of the Malpighian body . . 447
Branchiostoma Lubricum . . .80. 116
Breschet. On the presence of Pigment in the
membranous labyrinth of the ear of mam-
malia . . . . . .287
On imbibition of cartilages . . 312
On the communication of the medullar}' cells
of bone ..... 317
On a system of osseous canals in flat bones
91
413
425
430
444
Brewster, Sir David, on the fibres of the crystal-
line lens ..... 523
Bronchial glands .... 419
Bronchial tubes . . ... 305
Structure of . . . . . 395
Larger tubes ..... 395
Smaller ditto ..... 395
Mucous membrane of . . . .396
Epithelium of .... 39)
Muscular fibre of .... 396
Bruimer's glands . . . 420, 421
Structure of .... . 421
Distribution of. (Vide mucous Glands.)
Brunner's microscope . . . .31
Brans. On the membrane lining the cavities of
the true cartilages .... 307
On the nature of bone cells . . 321
Buccal glands ..... 419
Buffy Coat of Blood, conditions favourable to the
formation of ... 85
Built-up cells . . . .55
Cabinets for objects . . . .64
Cadaveric rigidity .... 366
Canada balsam. Method of mounting objects in 62
Camelidae. Blood of . . .90
Of dromedary . . .90
Of alpaco. . . . . .90
Of vicugna ..... 90
Of llama 90
Capybara, blood of . . .92
Carnivora, blood of . . . .92
Carpenter, Dr. On the structure of the striated
muscular fibrilla .... 358
On the analogy between striped and unstriped
muscular fibres .... 369
On the analogy between certain cartilage cells
and certain alga .... 314
PAGE
Cartilage. General structure of . . . 306
Division of into true and false . . 306
True Cartilages .... 306
Enumeration of ... . 306
Structure of 306
Matrix of . . . .306
Cavities of . . . . .307
Primary cells of .... 307
Secondary cells of ... . 308
Nuclei of ..... 309
Distinction of cartilage into true and false
fibro cartilages, to some extent artificial
Conversion of true into fibro cartilage
Union of true cartilage with ligament
Fibru-cartUages
Structure of ... .
Cells of ...
Fibres of .
Enumeration of . . .
Nutrition of cartilage
Pericondrium of
Vessels of cartilage .
Pathology of .
Ossification of . . .
Ulceration of .
Atrophy of ... .
Growtn and development of cartilages
Of the cells ....
By division of ditto .
By cytoblasts ....
By parent cells
Comparison of cartilage cells to certain alga?
Growth and development of the inter-cellular
substance ....
By a deposit of new layers .
By thickening of the wails of the cavities
Enchondroma
Uses of cartilage ....
To examine ....
Caruncuia Lachrymalis, structure of
Cat. Uulb of hair of .
Blood vessels of stomach of
Cells. Thin glass
Drilled .
Tube ...
Built-up .
Gutta-percha ....
Cements. Asphaltum
Canada balsam
Compound . . .
Gum Arabic ....
Japanner's gold size
Marine glue ....
Sealiug-wax ....
Cerebellum, ganglion cells of arbor vitae
Ditto of corpus dentatum
Ceruminous glands
Structure of
Charriere's syringe . .
Chevalier's microscope
Chromic acid
Chyle ....
Analysis of .
Molecular base of
Granular corpuscles of
Chylous blood
Oil globules of chyle
Minute spherules of
Coagulum of .
Serum of ....
Nature of . . .
Contrasted with lymph .
Colour of in thoracic duct .
Examination of .
Cilia .....
Circulation, capillary
In embryo of the chick &c.
(Extremities of young spiders, fins of fishes,
gills of tadpole and newt, tail of water-newt,
web of frog's foot and tongue of frog.;
309
309
309
309
310
310
310
310
311
311
311
312
312
312
312
312
312
312
313
313
313
314
314
314
315
315
316
418
304
411
54
54
54
55
55
49
50
50
51
49
50
50
377
377
441
441
41
30
58
67
68
69
69
69
69
69
69
70
70
78
269
125
129
INDEX.
551
PACK
. 81
Clot. Formation of
Ditto in biood after freezing . • 81
Constitution of . . . . .82
Length of time for formation of . . 8-2
Characters of in health and disease . . 82
Ditto in diseases of a sthenic character . 83
Ditto of in diseases of an asthenic character 83
Softening of fibroin . . . .83
Buffy coat of clot .... 83
Mode of formation of . . . .84
Adherence of red corpuscles in rolls in clot of
inflammatory blood ... 84
Conditions favourable to the formation of clot 85
Cupping of . . . .85
To what owing . . . . .85
Condition of red globules in 85
Colostrum. Corpuscles of 201
Disappearance of ditto . . . 21)2
Colostrum corpuscles peculiar to the human
subject 203
Purgative qualities of colostrum . . 203
Division of pregnant women into three classes
founded on its characters . . . 207
Comparetti. On the presence of pigment in the
membranous labyrinth of the ear of mam-
malia ...... 287
Compressor, the .... 30
Coppin, Mr. J. On the circulation in the tongue
of the frog 128
Corpora Wolffiana . . . .449
Corpuscles. Of the blood. Red corpuscles . 89
Colouring matter of . . . .95
Uses of . . . . . .97
Causes of colour of . . . .98
Iron in . . . . .98
Origin of .... 115
Phases of the development of . . .116
Final condition of . , .119
Blood globules of reptiles, fishes, and birds . 123
Ditto of CamelidaB .... 123
Ditto of the embryo of fowl . . . 131
Ditto of young frog .... 131
Blood corpuscles, dissolution of . . 132
Blood corpuscles of adult fowl . . 132
Ditto of tritons and frogs . . . 133
Effects of reagents on the red corpuscles . 135
Modifications the results of different external
agencies ..... 138
Ditto the effect of commencing dessication 138
Ditto the result of decomposition occurring in
blood abandoned to itself, without the body 139
Ditto the effect of decomposition in the blood
within the body, after death . . 139
Effects of certain remedial agents upon the
constitution and form of the red blood . 162
Effects of iodine on ditto . . . 163
Peculiar concentric corpuscles in blood 121, 122
Of Mucus. Structure of .
Nuclei of, single and compound
Form of .
Size of ...
Properties of
Nature of
Identity of with the pus corpuscle
PAGE
. 174
174
. 175
176
. 176
176
. 177
White corpuscles of blood. Number of . 100
Size of 101
Form of 101
Structure of . . . . . 101
Nucleus of 102
Properties of . . . . . 103
Position of in capillaries . . . 104
Motion of in ditto .... 105
Uses in connexion with secretion . . 105
Uses in connexion with nutrition . . 107
Aggregation of in capillaries . . . 108
Increased quantities of in disease . . 109
Processes by which they may be separated
from the red globules . . . 109
Origin of . . . .110
Opinions concerning .... 110
Different names for .... Ill
(" Central Particles " of Hewson ; " Escaped
Nuclei ; " " Parent Cells " of Barry ; " Tissue
Cells " of Addison ; " Fibrinous Globules "
of Mandl; "Granule Cells" of Wharton
Jones ; " Exudation Corpuscles " of Gerber ;
" Lymph Corpuscles " of Miiller.)
Mucous corpuscles, young epithelial scales 179
Of Pus. identity of pus with mucous corpuscles 183
Nature, origin, and formation of pus corpus-
cles ...... 184
Cowper's glands . . . 420, 421
Creosote . . . . . . 57
Crustacea, fat of . . . . 255
Crusta Petrosa ..... 335
Cruveilhier, on the calculi of the prostate . 437
Davy, Dr. On the increased quantities of white
corpuscles in the blood in inflammatory
affections ..... 109
On the presence of spermatozoa in the fluid
of the urethra after stool in a healthy man 236
Death. Signs of . . . . 86
Real and apparent .... 86
Coagulation of the blood, the most certain
sign of . . . . . .87
Delia Torre. On the annular form of the red
blood disc 93
Donne. His disbelief in the existence of a nucleus
in the red blood disc . . . .93
On the increased quantities of white corpus-
cles in the blood in disease . . 109
Opinions in reference to the blood globules . 110
His opinion that the white globules are red
blood corpuscles in process of formation 112
His observations on the conversion of milk
globules into white corpuscles . . 112
On the transition of white globules to red cor-
puscles 113, 114
Reasons in favour- of the opinion that the
red globules are formed out of the white 115
Opinion of, as to the cause of the mammilated
appearance of the red blood disc . 138
Vaginal tricho-monas of 181
Vaginal vibrios of . . . 182
Opinions as to the nature of pus globules 86
Venereal vibrios of . . . . 194
On cheese globules .... 196
The discoverer of colostrum corpuscles . 201
His statement that the colostrum corpuscles
are soluble in ether .... 202
On the recurrence of colostrum . . 204
Condition of milk after confinement, in con-
stant relation with its state during gestation 207
His division of pregnant women into three
classes, founded on the characters of the col-
ostrum during the last months of gestation 207
Lactoscope of . . . .211
On the formation of butter . . . 215
His detection of the spermatozoa in the vagi-
na on the second day . . . 227
Double decomposition. Injections by . 44
Drilled Cells 54
Dromedary. Blood of ... 90
Dry Way. Method of mounting objects in the 59
Dujardin. On the human spermatozoon 223, 224
His statement that spermatozoa lived thirteen
hours in the testicle after death . . 227
Ear, structure of. See Hearing, organ of . 523
Eble. On the hair at its full term of development 298
On nerves in the bulb of the hah of the cat 304
Elephant. Blood of . . • -92
Malpighian bodies of 44?
Enchoudroma . 315
Epidermis. Form, size, and structure of cells of 277
Correspondence of to epithelium . . 277
Disposition of .... 278
Ditto of line9 on the surface of . ' Sm
Effects of water on . . • .279
552
INDEX,
Epidermis of white and coloured races
Destruction and renewal of
Uses of
Pathology of .
Mr. Rainey's description of
Examination of
Epithelium. Constitution of
Distribution of
Different forms of
Tesselatcd variety .
Form of cells of .
Size of
Structure of . .
Distribution of
Colloidal variety .
Form and size of cells of
Structure of
Naked conoidal variety
Distribution of .
Ciliated variety
Distribution of .
Development and multiplication of epithel
Nutrition of dito ....
Destruction and renewal of ditto .
Uses of
Methods of examination of
Epithelial Tumours
Ether, injections
Eustachian glands ....
Evans, Dr. Julian. On the structure of the spl
Eye. See Vision
Dissection of .
PAGE
. 279
279
. 280
278
. 281
281
. 204
265
. 205
265
. 265
206
. 206
207
. 207
267
. 268
208
. 208
208
. 270
71
272
272
u7;j
275
275
43
419
een 489
509
5J3
mm
Fat. Vesicles of .
Contents of ditto
Form of ditto
Size of ditto .
Colour of ditto .
Consistence of ditto .
Structure of ditto
Distribution of fat
Quantity of
Disappearance of
Uses of
Distinction of fat vesicles from oil globules
Development of the fat vesicle
Examination of
Fibrin. Softening of
Fibrillation of
Fibrous Tissue
White Fibrous Tissue
Enumeration of parts constituted of
Morphous form of .
Amorphous form of
Condensed form of .
Reticular form of
Areolar form of . . .
Structure of
Action of acetic acid on
Yellow fibrous tissue . .
Enumeration of parts constituted of
Structure of
Varieties of .
Peculiar arrangement of
Mixed fibrous tissue . .
Nuclear form of fibrous tissue
Development of white fibrous tissue
Ditto of yellow fibrous tissue .
Fishes. Bone cells wanting in bone of
Fluids. Organized
Lymph
Chyle
Blood .
Mucus
Pus .
Semen . . .
Saliva
Bile
Sweat
. 254
254
. 254
255
. 255
255
. 255
259
. 260
261
. 262
262
. 538
263
. 83
353
. 346
346
. 346
347
. 347
347
. 347
347
. 347
347
. 348
349
. 348
349
. 350
353
. 349
352
. 352
322
. 66
67
. 67
79
. 171
183
. 218
240
. 241
242
. 243
Fluids. Urine
Pancreatic fluid
Lacrymal ditto .
Gastric ditto .
Preparation of
For mounting objects
Alcohol and Water
Goadby's Solutions .
Acetate of Alumina
Creosote
Glycerine
Canada balsam
Salt and Water .
Naphtha
Chromic acid
Method of mounting objects
Follicles. Of stomach
Of small intestines .
Of Lieberkiihn
Of large intestines .
Form of
Epithelium of
Blood-vessels of .
Follicles of uterus .
Of Fallopian tubes
Of vagina
Of resophagus .
Of neck of uterus
Of vesicula seminalis .
Of Schneiderian membrane
Forceps, dissecting
Cutting
Frog. Tongue of. Mode of exhibition of
TAGE
. 245
250
. 250
250
. 56
56
. 56
56
. 57
57
. 57
57
. 57
58
. 58
59
. 410
410
. 410
410
. 410
410
. 411
413
. 413
419
. 418
418
. 418
419
. 33
34
. 126
Gall Bladder. Structure of . . . 429
Galiina?. Spermatozoa of 220
Gastric juice ..... 250
Gelatine, injections with . . . 48
Gerber. On the relation between the size of the
blood globules and the capillaries . 92
His belief in the existence of a nucleus in the
red blood disc . . . . .93
On the structure of the spermatic animalculi
of the guinea-pig . . . 223
On the stellate bodies observed in decomposing
fat vesicles ..... 259
His description of the epithelium of the ven-
tricles as a tesselated ciliated epithelium 271
On nerves in the bulb of the hail- of the
guinea-pig .... 304
On the nature of bone cells . . 330
Gerlach. On the structure of the kidney . 450
On the structure of the Malpighian capsule 451
Gingival glands ..... 420
Glands. Definition of .... 406
Classification of . . . . .408
a. Unilocular glands . . . 410
Follicles of stomach . . . 410
Ditto of large intestines . . . 410
Ditto of Lieberkiihn . . . .410
Stomach tubes .... 412
Fallopian and uterine tubes or follicles 413
Solitary gland3 ..... 413
Aggregated or Peyer's glands. . . 414
b. Multilocular ditto .... 414
Sebaceous ditto .... 414
Meibomian ditto .... 416
Glands of the hair follicles . . . 416
Caruncula lachrymalis .... 418
Glands of nipple . . . .418
Ditto of prepuce .... 418
Mucous glands . . . . 418
Labial ditto . . . . .419
Buccal ditto . . . . .419
Tonsillitic ditto . . . . .419
Lingual ditto . . . 419
Tracheal ditto . . . . '419
Bronchial ditto . . . .419
Palatine ditto . . . . .419
Pharyngial ditto . . . .413
INDEX
553
PAOE
Glands of uvula . . . . .419
Dilto of Eustachian tubes . . .419
Brunner's glands . . . 420, 421
Cowper's ditto . . . 420, 421
Gingival ditto ..... 420
Uterine ditto ..... 420
Vaginal ditto . . . . .420
Lenticular ditto .... 420
c. Lobular ditto ..... 422
Salivary ditto . . . .422
Mammary glands .... 423
Liver 423
Prostate gland ..... 430
d. Tubular glands .... 437
Sudoriferous ditto .... 437
Axillary ditto . . . .441
Ceruminous ditto .... 441
New tubuiar gland in axillae kidneys . 441
Testis . . . . . .483
g. Vascular glands .... 484
Thymus gland . . . . . 484
Thyroid gland . . . .486
Supra-renal capsule .... 488
Spleen ..... 489
/. Absorbent glands .... 492
Lacteal or mesenteric glands . . 492
Lymphatic glands .... 492
Villi of intestines .... 493
Glass slides . .... 51
Cells . . ' . . . .54
Thin 51
Instruments for cutting ... 52
Globules of milk . ' . . . .197
Goadby's solutions * . 56
Goat. Blood of . ... 92
Goodsir. On the general development of the
teeth . . . . . .340
On the classification of glands . . 408
On the epithelium of the villi . . . 493
On the cells developed during absorption in
ditto ..... 494
Grallas. Spermatozoa of . . . . 220
Gruby and De la Font. M.M. On blood discs in
chyle ..... 71
Gueterbock. His opinion that the colostrum
corpuscles are true cells . . . 202
Guinea-pig, spermatozoa of . . . 219
Gulliver, Mr. Observations on the molecular
base of the chyle in the blood . . 69
On the lymphatics of the spleen . . 71
On the characters of the blood discs in the chyle 71
His opinion in favour of Hewson's views of
the thymus ..... 72
On the blood of the vicugna and llama . 90
On blood corpuscles in states of disease . 91
On the relation in the size of the blood cor-
puscles among the mammalia, and that of
the animal from which they proceed . 92
On the dimensions of the red blood discs of
the elephant, capybara, and napu musk-deer 92
His disbelief in the existence of a nucleus in.
the red blood discs ... 93
His measurement of the human colourless
blood corpuscle .... 101
His observations on the presence of white cor-
puscles in the blood in unusual quantities in
inflammatory affections . . . 109
His opinion that the white globules are red
blood corpuscles in process of formation . 112
His opinion that blood discs are the escaped
nuclei of the white corpuscles . . 117
On the blood of birds after a full meal . 118
On concentric corpuscles in the blood, which
he has styled " Organic Germs," or " Nucle-
ated Cells" . . . . .122
Gum Arabic cement . . .51
Gurlt. His statement that the fat vesicles in
lean animals contain serosity, and not grease 261
Glycerine . . . . . .57
Gutta-percha cells .... 55
PAGE
Haidlen. Inorganic components of milk of cow,
according to .... 195
Hair. Form of 291
Size of 292
Structure of . . . . .292
Ditto of root of . . ' . . .292
Ditto of bulb of . . . . 2y3
Ditto of sheath of ... . 293
Dilto of shaft of . . .294
Ditto of cortex of . . . .294
Ditto of fibrous layer of . 295
Ditto of medullary canal of . . 296
Ditto of follicle of . . . . 297
Growth of hair 298
Regeneration of ... . 298
Nutrition of . . . .299
Distribution of .... 300
Number of hairs in different situations . 300
Erection of . . . . 301
Colour of 301
Gray hair 302
Properties of hair .... 302
Hairs of different animals . . . 303
(Of the musk deer, sable, mouse, bat, martin) 304
Uses of hair ..... 304
Transverse sections of . . . . 305
Sections of, to mount . . . 305
Hair Follicles. Glands of 416
Distribution of ... . 416
Structure of .... . 416
Binary arrangement of . . . 417
Steatozoon folliculorum . . . 417
Havers. Glands of .... 260
Haversian canals ..... 318
Hearing. Organ of . . . 523
External ear ..... 523
Auricle, structure of ... 523
Cartilages of .... 523
Muscles of ..... 524
Auditory canal ..... 524
Cartilaginous part of ... 524
Osseous ditto ..... 524
Sebaceous glands of ... 524
Ceruminous ditto .... 524
Muscular fibres in . . . 524
Middle ear ..... 524
Tympanum ..... 524
Structure of .... 524
Tympanic cavity .... 525
Structure of membrane of . . 525
Openings into .... 525
Ossicles and muscles of ... 525
Transparent ceils in . . . . 525
Pigment cells in . . . . 525
Internal ear ..... 525
Osseous labyrinth .... 525
Membranous ditto .... 525
Perilymph ..... 525
Endolymph . . . 525
Structure of the spiral lamina of the cochlea 526
Denticulate lamina .... 526
Membranous zone .... 527
Structure of the cochlearis muscle . 527
Cochlear ligament .... 528
Muscular zone .... 528
Epithelium of scalae .... 528
Structure of the cochlear nerves . . 529
Of the membranous labyrinth . . , 529
Utriculus 529
Sacculus . . . . . .529
Membranous semi-circular canals . . 530
Otolith . . . . . .531
Otoconia ..... 531
Of the vestibular nerves . . . 531
Of the auditory nerves . . . 532
Hedgehog. Structure of spines of . . 304
Henle, M. Theory of the changes of the colour
of the blood . . . .136
Opinions as to the nature of the white corpus-
cles of blood, lymph, chyle, mucus, and pus 178
554
INDEX.
PAGE
Henle. His opinions as to the structure of the
milk globules : : 197
On the application of acetic acid to the milk
globules . . . . .199
His opinion that the colostrum corpuscles are
aggregations of granules in a mucoid, sub-
stance ..... 202
On the structure of spermatozoa . . 223
On the membrane of the fat vesicle . 256
On the nucleus of the fat vesicle . . 257
On the stellate bodies observed on decom-
posing fat vesicles . . . 259
On the presence of fat in the blood after re-
peated bleedings .... 262
On the absence of epithelium in the bursae 265
His description of the epithelium of the ven-
tricles as a cuneiform ciliated epithelium . 271
On the position of the pigment granules in the
cells ..... 288
On the fibres of the fibrous layer of the hair 295
On the medullary canal of hail- . . 296
On the membrane of the cavities of true car-
tilage 307
On the arrangement of the cells of articular
cartilage ..... 308
On certain large cells, presenting in their in-
terior a cavity in the cartilage of the epi-
glottis . . . . . .311
On the increase of the inter-cellular substance
of cartilages by the thickening of the mem-
brane of the cavities . . . 314
On the structure of the lamellae of bone . 320
On the nature of bone cells . . 330
On the structure of the inter-tubular substance
of dentine ..... 337
On a peculiar arrangement of the fibres of
elastic tissue .... 350
On the disposition of gelatinous nerve fibres 380
On the proportions of gelatinous nerve fila-
ments in different nerves . . 382
On the arrangement of the gelatinous nerve
filaments in ganglia .... 383
On the development of nerve cells on the sur-
face of the convolutions of the brain . 390
On the epithelium of the choroid plexuses . 538
Herbivora. Blood of . . . .92
Hewson. On the lymphatics of the spleen . 71
His opinion that the thymus is an appendage
to the lymphatic system, chyle globules, or
the corpuscles of the thymus . . 72
His belief in the existence of a nucleus in the
red blood disc . . . : 93
Hodgkiii. His disbelief in the existence of a
nucleus in the red blood disc . . 93
Haematine . . . . . .95
Hooke. On the hair . . : .296
Horner, Professor: On the axillary glands . 441
Hunter. On the persistence of fat vesicles . 261
Huschke. On the structure of the kidney . 450
Inflammation. Causes of
Exciting cause .
Proximate cause
Injections. Minute
Objects of
Of arteries
Of Veins
Syringes used in
By Swammerdam's Syringe
By Charriere's ditto
Materials used in . ,
With turpentine
With ether .
By double decomposition
Of one set of vessels
With gelatine
With fresh milk . ,
Introduction . .
140
140
140
38
38
39
411
40
40
41
42
42
43
44
48
48
PAGE
Jacobi. Experiments in fertilizing the ova of a
carp ..... 234
Japanner's gold size . . . .49
Johnson, Dr. G. On fatty degeneration of the
kidney .... 454, 407
On the inflammatory diseases of ditto . 462
Jones, Mr. Wharton. On the presence of a nu-
cleus in the blood disc of the lamprey .
On the mulberry or granulated appearance of
the red blood disc • . . .94
On the structure of the red blood corpuscle 95
Opinions concerning the white blood corpuscle 111
Observation on the blood corpuscle, consider-
ed in its different phases of development in
the animal series .
On the nuclei of mucous corpuscles .
On the brown pigment of the membranous
labyrinth of the ear of man . . 287
On the tubular character of the gelatinous
nerve filaments .... 382
On the structure of the ganglion caecum in the
dog 382
Jones, Dr. Handfield. Reasons for his non-belief
in the existence of a lobular biliary plexus
His investigations as to the terminations of the
biliary ducts
On the arrangement of the hepatic cells in
connexion with secretion
On the union and consolidation of the hepatic
cells ....
Description of the active and passive condi-
tions of the lobules of the liver -
Ou the development of the liver .
On the calculi of the prostate .
On the peculiar corpuscles in the spleen
On the epithelium of the villi .
On the granular substratum in ditto
On oil drops in ditto
9J
116
175
425
426
427
427
428
434
437
491
493
494
494
Kidney. Secreting apparatus of . . 442
Tubes of . . . . . .442
Tubes of, in cortical part . . . 442
Tubes of, in medullary part . . . 442
Basement membrane of . . 443
Frame-work for the lodgment of tubes . 443
Malpighian dilatations . . . 443
Vessels of . . . . .443
Capsules of . . . . . 444
Epithelium of the tubes . . . 444
Ditto of Malpighian dilatations . . 444
Ditto of neck of Malpighian dilatations . 444
Vascular apparatus of kidney . . 444
Renal artery . . . . .444
Renal vein ..... 445
Inter-tubular plexus .... 445
Portal vein ..... 445
Portal system . . . . .445
Afferent vessel of Malpighian tuft . 445
Efferent vessel of Malpighian plexus . . 445
Malpighian body, structure of, when complete 447
Malpighian bodies of birds and reptiles . 448
Size of ..... 448
In elephant and birds .... 448
Development of the kidney . . . 449
True capsule of the Malpighian tuft . . 452
Pathology of the kidney . . . 453
To inject . . . . . .482
Kiernan. His description of the biliary ducts,
and of the lobular biliary plexus . 424
On the acini of the liver . . . 424
Kieser. On the pigmentary membrane of the eye 286
Kolliker. On the absence of internal organs in
spermatozoa ..... 225
On the development of spermatozoa . 231
On non-striated muscle .... 371
On the structure of the kidney . . 450
Labial glands
Labelling slides, method of
Lachrymal fluid
419
63
250
INDEX,
555
PAGE
Lachrymal glands .... 423
Lacteal or Mesenteric glands . . . 4l»ii
Lactoscope . . . • .211
LaUemand. On the development of spermatozoa 230
Lambotte. His disbelief in the existence of a
nucleus in the red blood disc . . 93
Lamina fusca, pigment cells of . . • 288
Lampenhoff. On living semen in the vesicular
seminales of dead men . . ' 227
Lamprey. Blood of . . . .91
Lane, Mr. Analysis of chyle . . 68
On blood discs in the chyle . . .71
His belief in the existence of a nucleus in the
red blood disc .... 93
Views on the structure of the red blood cor-
puscle . . . . .95
Llama. Blood of ... 91
Lealand and Powell. Microscope of . . 29
Letheby, Dr. H. On cell-like bodies in the bile 243
On the calculi of the prostate . . . 437
Leeuwenhbek. The first to describe the blood
globules in different animals . . 89
The discoverer of milk globules . . 197
His discovery of living spermatozoa in the
uterus and Fallopian tubes of a bitch, seven
days after connexion . . 227, 233
On the discovery of spermatozoa . . 218
On the spermatozoa of the ram and rabbit 223
The discoverer of epithelium cells in the mu-
cus of the vagina ...
The first to observe that the epidermis was
composed of scales . . . 277
On the hair 296
Lenticular glands .... 420
Liebig. On the condition of iron in the blood 98
Liq. potass., action of, on pus . 10G, 188
Liston, Mr. His disbelief in the existence of a
264
nucleus in the red blood disc
Lingual glands ....
Liver ......
Secreting apparatus of
Lobules of ...- •
Form of ....
Size of .....
Union of ....
Inter-lobular fissures ....
[nter-lobular spaces ....
Follicles, or acini ....
Biliary ducts .....
Lobular biliary plexus ....
Doubts concerning ....
Mode of termination of . .
Structure of .
Secreting cells .....
Structure of .
Linear and radiated disposition of
Union of .... .
First secretion of bile in central cells .
Active and passive conditions of the lobules
of the liver ....
Dissolution of membrane of
Gall bladder .....
Structure of ....
Vascular apparatus of liver
Hepatic veins .
Central-lobular veins
Sub-lobular veins .
Portal veins .
Inter-lobular veins .
Lobular capillary plexus
Hepatic artery .
Pathology of liver . . . •
Development of .
Prostate gland ....
Structure of . • •
Epithelium of .
Calculi of .
Increase of in old age
Injection of ....
Locus Niger. Ganglion cells of
93
419
423
424
424
424
424
424
424
424
424
424
425
425
426
426
426
427
427
4-27
4-27
428
429
429
429
4'.I0
430
430
430
430
430
431)
431
432
434
436
436
436
436
43l>
435
377
PAGE
. 395
395
. 396
396
. 397
396
. 396
397
. 397
398
. 398
398
. 398
398
. 398
the air cells of 404
. 404
405
. 76
77
. 492
67
. 68
68
. 69
69
Lungs. Jleriferous apparatus of
Bronchial tubes
Air cells .
Form of
Size of
Structure
Communications of
Models of
Epithelium of
Vascular apparatus of
Arteries .
Veins .
Capillaries
Natural inflation of lungs
Artificial ditto
Mr. Rainey on epithelium in
Of birds .
Injection of .
Lymphatics. Structure of
Valves in
Lymphatic glands. Structure
Lymph .
Analysis of
Coagulum of .
Granular corpuscles of .
Serum of
Examination of .
Lymphatic system. Structure of lymphatics 67
Ditto of lacteals . . . . .68
Ditto of lymphatic glands . . . 492
Ditto of mesenteric glands . . . 492
Thoracic duct . . . . 6S
Blood in lymphatics of spleen . . .70
Madder. In bones of animals fed with . 324
Magendie. His disbelief in the existence of a
nucleus in the red blood disc . . 93
Experiments of, on the blood . . 153
Malpighi. The discoverer of the red globule 88
Mammary Glands. Structure of . . 423
Efferent ducts of . . . .423
Milk globules in follicles of . . 423
Follicles of . . . .423
Existence of mammary gland in the human
male 423
Epithelium of . . . 423
Degeneration of mammary glands in age . 423
Lacteals of 423
Man. Spermatozoa of ... 219
Mandl. On the blood of the dromedary and
alpaco . . • • • .90
His belief in the existence of a nucleus in the
red blood disc .... 93
His opinion that the formation of the nucleus
of the blood corpuscles of reptiles takes
place subsequently to the removal of the
blood from the system • . . 124
Opinion as to the nature of pus and mucous
globules ..... 186
Opinion as to the structure of milk globules 197
On the structure of the fat vesicle . . 257
On stellate bodies observed in decomposing
fat vesicles . . . . .259
Marine glue ..... 50
Martin. Structure of hair of . . .304
Materials used in injections ... 42
Mayer, E. H. On the nature of bone cells . 330
Medulla Oblongata. Ganglion cells of . 377
Menobranchus. Bone cells of . . 321
Meibomian glands . . . . 416
Number of .... 416
Form of . . . .416
Structure of . . • .416
Meckauer. On the structure of cartilage . 311
Microscope. Of Allen . . . .33
Brunner ..... 31
Chevalier . . . . . .30
Oberhauser ..... 30
Pike & Sons 33
Powell & Lealand .... 29
556
INDEX
PAQE
Microscopes. Of Ross . . . .29
Smith & Beck .... 30
Spencer . . . , . .31
Microtome . ... 34
Milk. Inorganic components of . . 195
Organic constituents of 195
Analysis of ... 209, 211
Serum of . . . .196
Cheese globules of . . . . 196
Fatty ditto of .... 197
Form, size and structure of . . 197
Opinions of observers as to the structure of 197
Action of boiling water, boiling alcohol, the
alkalies, acetic acid, and asther on . 200
Colostrum of . . . . 201
Pathology of milk .... 203
Milk of unmarried women . . . 206
Ditto of women previous to confinement . 206
Ditto of women who have been delivered, but
who have not nursed their offspring . 208
Milk in the breasts of children . . 208
Different kinds of milk .... 208
Relative proportions of the elements of milk
in woman, the cow, the goat, and the ass 209
Good milk ..... 210
Poor milk ..... 212
Rich milk ..... 213
Adulteration of milk . . . 213
Formation of butter .... 214
Milk abandoned to itself . . . 215
Penicillum glaucum in . . . . 216
Medicines in milk .... 217
Injections with milk . . . .48
Mitscherlich. Observations on the saliva 241
Mondini. On the pigment of the eye . 286
Mounting objects. Method of . . .56
The dry way ..... 59
In Canada balsam with heat . . .60
As opaque ..... 63
Mouse. Spermatozoa of . . . . 219
Structure of hair of . . . . 304
Mucus. General characters of . . . 171
Ditto of true, false, and mixed membranes 172
Corpuscles of .... 174
Mucus of different organs . . . 179
Vaginal and uterine ditto . . .180
Effect of acid mucus on the teeth . . 180
Tricho-monas in vaginal mucus . . 181
Vibrios in ditto .... 182
Distinctive characters of mucous and pus . 186
Mucous Membranes. True or compound 172
False or simple and mixed . 172, 418
Compound. Alimentary canal from cardia
downwards ..... 419
Gall-bladder, oesophagus, vagina . 419
Neck of uterus, vesiculae seminalis . . 419
Simple. Eustachian tubes . . . 419
Trachea, bronchial tubes, and bladder 419
Unimpregnated uterus .... 419
Mixed. Mouth and nose . . . 419
Mucous Glands. Structure of . . 420
Follicles, epithelium, and membrane of 420, 421
Muller. On blood discs in the chyle . . 71
On the quantity of blood in the system . 80
On the coagulation of blood after freezing 81
On the blood of the frog . . .82
His belief in the existence of a nucleus in the
red blood disc .... 93
His verification of the white globules in the
blood of a frog . . . .100
On spermatozoa .... 223
On the terminations of nerves in the mem-
brana nictitans .... 385
On the kidney .... 450
Muscle. Voluntary .... 354
Involuntary ..... 354
Of animal and organic life . . . 354
Striped and unstriped . . . 354
General structure of muscle . . . 355
Of unstriped muscular fibrilla . . 355
Muscle. Nuclei of unstriped fibrilla
Muscular structure of the heart
Of striped muscular fibre . .
Size and form of
Size of, in foetus and adult . .
Cause of striation of
Differences of opinion as to
Lacerti, or bundles of fibres
Structure of fibrillar of fibres .
Nuclei of ... .
Situation of, in the fibre . .
Sarcolemma
Cleavage of fibre . .
Blood-vessels of muscles
Nerves of ditto ....
Union of muscle with tendon .
Muscular contraction
Active and passive contraction of muscle
Zigzag disposition of the fibres in .
Approximation of the strife in
Increase in the diameter of the fibre in
Rigor Mortis ....
Muscular sound
Developments of muscle, three stages of
Differences of opinion as to striation
Kolliker. On non-striated variety of .
Examination of
Muscular rigidity. A sign of death
Musk Deer. Structure of hair of
PAGE
. 3.j.)
356
. 357
357
. 357
358
. 358
357
358, 547
359
. :^9
355, 359
. 361
355, 301
. 361
362
363
303
363
365
365
366
366
367
358
371
375
87
304
Nachet. Microscope of . 31
Nails. Structure of . . . .282
Development and Pathology of . . 283, 284
Modification of in the animal kingdom . 285
Regeneration and Examination of . . 285
Mr. Rainey on the structure and formation of 541
Naphtha . . . . . .58
Napu Musk Deer. Blood of . . .92
Nasmyth Mr. On the constitution of the inter-
tubular substance of dentine . . 337
On secondary dentine . . . 337
His opinion that the cementum passes over the
entire surface of the enamel of the tooth 338, 344
On the development of dentine . . 341
Nasse, Professor. On the adherence of the red
corpuscles in rolls 84
On a mottled appearance characteristic of in-
flammatory blood . . . .85
His opinion that the white globules are red
blood corpuscles in process of formation 112
On the milk globules .... 200
On the speedy disappearance of colostrum
corpuscles in women who have borne many
children ..... 203
Needles. Dissecting . . . .35
Nerves. Cerebro-spinal system . . 376
Sympathetic ditto .... 380
Structure of nerves .... 376
Of cerebrospinal system . . . 376
Secreting, or cellular structure of . . 376
Disposition of . . . . 376
Granular base and cells of . . . 376
Caudate ganglion cells and distribution of . 377
Globular ganglion cells. Distribution of . 378
Of the tubular struct ure . . . 378
Of the cerebrum and nerves of special sense 378
Of cerebellum and spinal cord . . 378
Of posterior root of spinal nerves . . 378
Of sympathetic system and motor nerves 378
Varicose dilatation of the tubes . . 378
White substance of Schwann in . . 379
Neurilemma ..... 379
Axis cylinder ..... 380
Globules of white substance of brain . 380
Ditto of spinal marrow, and nerves of special
sense . . . . . .380
Of sympathetic system . . . 38.)
Structure of nerves of . . . . 360
Gelatinous nerve fibres of . . . 380
Where best seen .... 3dl
557
PAGE
Nerves Proportion of nerve fibres in different 381
Structure of ganglia . . . 381
Tubular and gelatinous nerve fibres in . 383
Arrangement of .... 383
Ganglion globules and nerve fibres in . . 384
Origin and termination of nerves . . 384
Origin in loops ..... 384
In ganglion cells .... 385
Termination in loops . . . 385
In definite extremities . . . 386
Blood-vessels of nerves . . . 384
Pacinian bodies .... 386
Development of nerve fibres . . . 388
Ditto of ganglionary cells . . . 389
Regeneration of nervous matter . . 390
Researches of M. Robin . . 29 1
Examination of . . . . . 394
Nesbitt. The first to distinguish between the
two forms of ossification . . . 325
Neurilemma ..... 379
Nipple, glands of . . .418
Nose. Structure of mucous membrano of.
See Smell ..... 505
Nutrition, corpuscular theory of . 99, 108
Oberhauser. Microscope of . .30
Objects of minute injections ... 38
Oesophagus. Muscular fibres of, striped and
unstriped ..... 360
Omnivora. Blood of . . . .92
Opaque objects. Methods of mounting . 63
Organs of ihe senses. Touch . . 497
Taste . . . . . .501
Smell and Vision .... 505
Hearing . . . . . .523
Owen, Mr. His disbelief in the existence of a
nucleus in the red blood disc . . 93
On the development of dentine . . 341
Pacini. On the Pacinian bodies . . . 386
Pacinian bodies. Situation and structure of 386
Inner system of capsules of . . 387
Termination of nerve in . . . 387
Inter-capsular ligament of . . . 387
Varieties in form and structure of . . 388
Pacchionian glands. Situations and forms of 538
Palatine glands .... 419
Palmipedes. Spermatozoa of . . 220
Pancreatic fluid .... 250
Papillae of skin ..... 498
Examination of ... . 500
Pappenheim. On the structure of the kidney 451
Passeres. Spermatozoa of . . 219
Pathology. Of the blood . . ' . x .142
Of the red corpuscle . . . 142
Increase of in plethora .... 143
Decrease of in anaemia . . . 144
Increase of, under the influence of recovery
and certain medicinal agents . . 146
Effects of disease on the white corpuscles . 146
Deficiency of fibrin in fevers, typhus, small-
pox, scarlatina, and measles . . . 147
Increase of fibrin in inflammatory affections,
as pneumonia, plueritis, peritonitis, acute
rheumatism .... 148
Condition of the blood in hemorrhages . 151
Decrease in the normal portion of albumen 154
Becquerel and Rodier's pathological researches
on the blood ..... 158
Blood in ecchymoses . . . 161
Of milk. Persistence of, in the condition of
colostrum ..... 203
Recurrence of colostrum . . . 204
Influence of retention of milk . . 204
Pus and blood in milk . . . 205
The milk of syphilitic women . . . 206
The milk of women in case of the premature
return of the natural epochs . . 206
Of the semen ..... 234
Of the urine ..... 246
PAGE
Pathology. Of albuminous urine . . 247
Fibrinous, fatty, chylous, and milky ditto 248
Excess of mucus in ditto . . . 249
Blood in ditto . . . . .249
Pus in ditto ..... 250
Of epidermis ..... 278
Of nails ..... 284
Of pigment cells ..... 286
Of cartilage . . . . .311
Of the lungs. Emphysema . . . 399
. Asthma and pulmonary apoplexy . . 400
Pneumonia and tubercles . . . 401
Of liver. Secreting apparatus . . 432
Biliary and fatty engorgement of cells . 432
Vascular apparatus. Anaemic condition of
lobules 433
First stage of hepatic venous congestion . 433
Second stage of ditto .... 433
Nutmeg or dram-drinker's liver . . 433
Portal venous congestion . . . 433
Hydatids and cysts in liver . . . 434
Of the bile . . . . .433
Of kidney. Fatty condition of . . 452, 467
Pathology of "Blight's disease," according to
Toynbee ..... 455
Sub-acute inflammation of the kidney . 457
Cystic disease of ditto . . 458, 465
Inflammatory diseases of the kidney . . 462
Acute desquamative nephritis . . 463
Chronic ditto ..... 464
First and second form of fatty degeneration 467
Exudation, and ditto within the tubes . 469
a. Crystalline or saline deposits . . 460
b. Oleo-albuminous exudation . . 470
c. Exudations in the form of pus . 470
Exudation within the Malpighian bodies . 470
Exudation in the inter-tubular tissue . 470
Partial distribution of the oleo-albuminous
exudation . . . ... 470
Lesions affecting chiefly the vascular system 471
Congestion followed by permanent oblitera-
tion of capillaries of cortical substance 472
Waxy degeneration .... 472
Lesions of the tubes and epithelium . . 474
Imperfect development of cells and nuclei 474
Desquamation of the epithelium . . 474
Obliteration of the tubes . . . 475
Microscopic cyst formation . . . 476
Dilatation and thickening of the tubes . 478
Conclusion ..... 479
Of thyroid gland. Condition of, in goitre . 488
Paint injections . . -42
Peyen. His analysis of the milk of woman 209
Pearson. On the colouring matter of the lungs
and bronchial glands . . . 287
Peligot, M. His observations on milk retained
for a long time in the breast . . 204
Peyer's glands ..... 414
Pharyngeal glands . . . .419
Pia mater. Structure of . . . . 537
Choroid plexuses and velum inter-positum of 538
Villi, blood-vessels, and epithelium of
. 538
Pig. Fat vesicles of .
254
Bulb of hair of .
304
Pigment Cells. Structure and situation of
286
Pathology of and freckles
. 287
Cells of the choroid .
288
Of the iris and ciliary processes
. 288
Of the lamina fusca .
288
Pigment cells in the skin
. 289
Ditto of outer surface of choroid .
289
Pigment granules
. 289
Examination of . .
290
Pike and Sons. Microscope of .
. 33
Pineal Gland. Caudate cells of
536
Compound and calcareous cells of
. 536
Earthy matter of
536
Blood-vessels and nerve tubules of
. 537
Pipettes ....
37
Pituitary gland. Lobes of . .
. 535
558
INDEX,
PAGE
Pit'y glands. Stracture and infundibuJum of 535
Comparison of, to a ganglion . . . 535
Porcupine. Bulb of spines of . . 304
Powell and Lealand. Microscope of .29
Preparation of objects .... 37
Prepuce, glands of .... 418
Preservation of objects ... 49
Prevost and Dumas. Their observations of liv-
ing spermatozoa seven days after connexion 233
Experiments on the semen . . . 234
Proteus. Blood globules of . . .123
Shape of bone cells of . . . .321
Purkinje. On the vibratile epithelium of the
ventricles ..... 271
Purkinje and Valentin. On ciliary motion 269, 270
Pus. General characters of . . . 183
Distinctive characters of pus and mucus . 186
Action of liq potass, and sol. amon. on pus 106,188
Distinctions between certain forms of pus and
mucus ...... 190
Detection of pus in blood . . ly 1
False pus ..... 192
Metastatic abscesses .... 193
Quekett Mr. His disbelief in the existence of
a nucleus in the red blood disc . . 93
His opinion on the mammillated appearance
of the red blood disc . . . 139
On bone cells ..... 322
On the calculi of the prostate . . 437
On looped blood-vessels in the olfactory re-
gion of the fcetus .... 508
Quevenne, M. On the cheese globules . 196
On the milk ditto .... 200
Rainey, Mr. On epidermis . . .281
On the structure and formation of the nails 541
On the ganglionic character of the arachnoid
membrane of the brain and spinal marrow 543
On healthy air cells .... 397
On sudoriparous glands . . . 439
On lungs of birds .... 404
On the structure of the sudoriferous glands 547
On the synovial fringes .... 247
Ram. Spermatozoa of 223
Rapaces. Spermatozoa of 220
Rapp. On nerves in the bulb of the hair of the
seal, porcupine, &c. . . . 304
Rat. Spermatozoa of . . . 223
Rees, Dr. G. O. Analysis of lymph . . 68
His belief in the existence of a nucleus in
the red blood disc . . . .93
On the structure of the red blood corpuscle 95
On the urine of persons taking cubebs, &cc. 247
Reichart. On the kidney . . .450
Reptilia. Blood globules, form and size of . 123
Structure of . . . . . 124
Action of water on ... . 124
Ditto of acetic acid on . , 125
White globules of . . .125
Plastic properties of red ditto . . 125
Fat of reptiles ..... 255
Malpighian bodies of 426
Respiration. Corpuscular theory of .99
Rhinorceros. Blood of ... 92
Rigor Mortis ..... 366
Robin, M. C. Researches on the nervous system 391
On the axillary glands .... 441
Rodentia. Hair of . . . 304
Ross. Microscope of . . .29
Sable. On the medullary canal of hair of 296
Ou the structure of the hair of . . 304 I
Salamander. Spermatozoa of . . 223
Saliva. Amount of ... . 241
Mitscherlich's observations on . . 241
Solid constituents and salts of . . . 241
Acetic acid in .... 241
Admixture of saliva with mucus . . 241
Uses of .... 242
PAGE
. 422
422
. 57
355
. 33
223
Salivary Glands. Stracture of .
Follicles and form of, in embryo .
Salt and water
Sarcolemma ....
Scalpels for dissection
Scansores. Spermatozoa of .
Scarpa. On the presence of pigment in the
membranous labyrinth of the ear of Mam-
malia ...... 287
Scherer. On pigment cells in the bile . 243
Schuliz. Observations on the action of oxygen
and carbonic acid on the form of the blood
corpuscles .... 136, 137
Ditto of iodine on ditto . . .163
Schumlansky. On the structure of the kidney 450
Schwann. On the membrane of the fat vesicle 256
On the nuclei of the fat vesicle . . 256
On the motion of the pigmentary granules in
the cells of the choroid . . . 288
On the membrane lining the cavities of true
cartilage ..... 307
On Ihe nature of bone cells . . 330
On the tubular nerve fibre in the early stages
of its development .... 382
Sebaceous glands. .... 414
Distribution, secretion, and cells of . . 415
Structure of ... . 416
Sequin. On the amount of fluid passing off by
the skin ..... 243
Semen. Characters of . . . 218
Spermatozoa .... 218
Pathology of semen . . " . . 234
Application of a microscopical examination
of the semen to legal medicine . . 237
Sharpey, Dr. On the structure of the lamella of
bone . . . . . .320
On infra-membranous ossification . . 325
On the striated muscular fibrilla . . 358
Sidall. On the increased quantities of white cor-
puscles in the blood of the horse in influenza 109
Siebold. On the absence of internal organs in
the spermatozoa .... 225
On the development of spermatozoa . 230
On living ditto in the uterus and fallopian
tubes eight days after connexion . . 233
Simon, M. Organic constituents of human
milk, according to . . . 195, 209
Analysis of sweat .... 244
Simon, Mr. On the thymus . 73, 485, 486
On sub-acute inflammation of the kidney 457
Siren. Blood globules of
Bone cells of
Skey. Qn the size of muscular fibres of
heart ....
Skin. See Touch ....
Smell. Structure of mucous membrane
nose ....
Tactile region ....
Epidermis, papillae, and hairs of .
Sebaceous glands of
Pituitary region . . .
Epithelium, and mucous follicles
Blood-vessels of
Olfactory region. Position of .
Characters, epithelium, and glands of
Pigment cells and blood-vessels of
Looped ditto of in foetus .
Gelatinous nerve filaments of .
Olfactory lobes and filaments
Smith and Beck. Microscope of
Spallanzani. The discoverer of the white
bules in the blood of salamanders
123
321
he
356
. 497
of
505
. 506
506
. 506
506
. 505
506
. 506
507
. 508
508
. 508
508
. 30
100
Experiments on frogs with spermatized water 234
Spencer. Microscope of . .31
Spermatophori ..... 228
Spermatozoa ..... 218
Form of (in man, the rat, the mouse, guinea-
pig, in birds, tritons, and salamanders; . 219
Size and structure of . . . 220, 221
Motions and mode of progression of . . 225
INDEX.
559
PAGE
Spermatozoa. Duration of motion . . 22G
Effects of reagents on . . . . 227
Development of .... 229
Spermatoaoa essential to fertility . .232
Condition of, iu hybrids . . . 233
Spinal Chord, ganglion cells of . . . 377
Spleen. Structure and capsule of . . 489
Blood-vessels and secreting structure of . 489
Dr. Jullien Evans on ... 489
Dr. Jones on .... . 491
Peculiar corpuscles in 491
Lymphatics of . . . .70
Solids 253
Fat 254
Epithelium ..... 264
Epidermis ..... 277
Nails 282
Pigiuent cells ..... 286
Hair 291
Cartilages . . . . .306
Bone ...... 317
Teeth . . . . . .335
Cellular or fibrous tissue . . . 346
Muscle 354
Nerves ..... 376
Glands ...... 406
Solitary Glands. Distribution and structure of 413
Orifices of . . . . .413
Follicles of Lieberkhiin . . . 414
Supra-renal Capsule. Structure and tubes of 488
Molecules, granular nuclei, and parent cells of 488
Differences in medullary and cortical portions 488
Vascular distribution in . . 488
Capsule of .... 489
Steatozoon Folliculorum . . . 403
Stomach Tubes. Arrangement of . . 412
Form, structure, and epithelium of . 412
Existence of in the duodenum . . 412
Modification of, near the pylorus . . 412
Sudoriferous Glands .... 437
Distribution and structure of . . 437
Tubes and ducts . . . .438
Secreting cells, number of . . . 438
Mr Rainey's description of . . 439
Examination of ... 440
Structure of, according to Mr. Eainey . . 547
Swammerdam's syringe ... 40
Sweat. Quantity of ... . 243
Scales of epidermis in 244
Solid constituents and analysis of . . 244
Crystals in . . . . 244
Pathology of . . . .245
Synovial Fringes .... 547
Syringes used iu injections . . .40
Table of magnifying powers .
Taste. Structure of mucous membrane of
Chorium and papilla? of
Simple and compound .
Filiform, and fungiform
Variety of ditto, and calyciform
Foramen caecum
Mucous follicles and epithelium of
Filiform appendages of
Gustatory region of
Teeth. General structure of .
Dentine .....
Modifications and tubes of .
Secondary formation of, in cavity of tooth
Coustitution of . . . .
Ditto of inter-tubular substance, accordin
Nasmyth ....
Ditto, according to Henle
Peculiar globular formation in . .
Cementum ....
Bone cells, and Haversian canals of .
Hexagonal and granular layers of .
Dentinal tubes in
Cementum and dentine, modifications of
other ....
29
501
501
. 501
502, 503
. 503
503
504
5U4
502
335
335
336
337
337
337
337
337
337
337
337
338
PAGE
Teeth. Enamel. Fibres and cells of . 338, 339
Form and arrangement of ditto . . 339
Pulp of tooth. Structure of . . 339
Development of teeth. General particulars of 339
Formation of dentine and dentine pulp . 341
Membrane of ditto, Formation of enamel 342
Enamel pulp. Cells of . . . .342
Formation of cementum and cementum pulp 343
Caries of the teeth .... 344
Tartar on ditto .... 345
To make sections of . . . 345
Testis. Structure, tubes, and cells of . 483
Thoracic duct . . . . .68
Fluid, red colour, and composition of . 70
Blood and granular corpuscles in . 70, 71
Thymus. Follicles of . . . .484
Structure of .... . 485
Limitary membrane and lobular arrangement 486
Blood-vessels and reservoir of . . . 485
Mucous membrane and capsule of . . 485
Blood-vessels in, and milky fluid of follicles of 485
Granular and nucleated cells of . . 73. 485
Thyroid. Vesicles of 486
Structure, lobules, and blood-vessels of . 487
Nuclei and cells of ... . 487
Todd and Bowman, Messrs. On two forms of
Haversian canals . . . .319
Experiments on bone cells, suggested by 322
Their opinion that the nuclei of cartilage cells
become developed into bone cells . 328
On the granular blastema in cancelli of bones 329
330
347
356
358
359
360
363
369
379
412
420
498
each
33S
On the nature of bone cells
On the structure of white fibrous tissue
On the muscular structure of the heart
On " sarcous elements " . .
On the nuclei of striated muscular fibre
On the striated muscular fibre .
On muscular contraction . .
On the development of muscle
On the neurolemma
On the occurrence of gelatinous fibres in parts
where their nervous character is indubitable 382
On the termination of nerves in loops in the
papillae of the skin and tongue . . 385
On the epithelium of the stomach cells . 411
On a modification of the follicles and stomach
tubes near the pylorus
Opinions as to the mucous glands
On the termination of the nerve tubules in the
papilla; of the tongue
On a fibrous structure in the papilla? of tongue 498
On the olfactory region . . . 506
On the olfactory filaments . . . 508
On the tubular structure of the cornea proper 512
On the anterior elastic lamina of cornea . 513
On the membrana pupillaris . . . 518
On certain elastic fibres attached to the pos-
terior elastic lamina . . . 518
On the granular layer of the retina . . 519
On a layer of cells situated on the hyaloid
membrane ..... 521
Tomes, Mr. On the development of bone . 328
H is lectures on teeth . . . 336
Description of granular layer of cementum 337
On the development of dentine . . 341
On the cells of the cementum pulp . 343
On the spaces between the fibres of newly-
formed enamel .... 343
On tubes of carious dentine . . 345
Tongue. Structure of. See Taste . . 501
Ditto of frog ..... 126
Tonsillitic glands ..... 419
Touch. Seat of . . . .497
Papillae of . . . . .497
Epidermis of . . . . . 499
Distribution and arrangement of . . 497
Structure and basement membrane of . 498
Nuclear contents of . . . 498
Blood-vessels of ... 499
Nerves of and fibres' in 498
>00
INDEX,
Toynbee. Oh the structure of Malpighian body 453
Oq the corpus Malpighianum
On the pathology of " Bright's disease"
Tracheal glands ....
Tricho-monas .....
Troughs for dissection ....
Tube cells
Turpentine injections ....
Turpin. His opinion that the milk globules con-
sist of two vesicles enclosing fine globules
and buttery oil ... 197
His idea that" the fungus, penicillum glaucum,
was developed from the milk; globules . 216
Urine. Specific gravity of 245
Analysis of ..... 240
Solid organic constituents of, viz : mucous cor-
puscles and epithelial scales . . 246
Spermatozoa in . . . . . 246
Pathology of . . . . .246
To examine ..... 252
Uterine glands .... 420
Uterine and Fallopian tubes . . 413. 419
Spheroidal epithelium of . . .413
420
35
80
223
2 -J 4
230
271
Vaginal glands . . . . .
Valentin's knife ....
Valentin. On quantity of blood in the system
On the supposed stomach of spermatozoa
On the spermatozoa of the bear
On the development of spermatozoa
On the ciliated epithelium of the ventricles
On the occurrence of pigmentary ramifica-
tions in the cervical portion of pia mater
On the disposition of nucleated or gelatinous
nerve fibres .
On the termination of nerves in pulp of teeth
On the structure of the kidney
Valentin and Schwann. Their researches on the
development of muscular fibre
Valves in lymphatics ....
Veins, injection of . . .
Vibrious, vaginal ....
Ditto venereal .
Vicugna, blood of ...
Villi. Of the intestines, distribution of
Structure and epithelium of
Basement membrane and nuclear contents of
Oil-drops in and blood-vessels of .
Lacteals and peculiar form of .
Examination and injection of
Of the pia mater . . . •
Vision. Structure of globe of the eye r .
Sclerotic. Structure of .
Tunica albuginea and vessels of
Cornea. Structure and lamina? of
Conjunctival epithelium and cornea proper
Pf.atpj-inr and anterior elastic lamina .
PAOH
Vision. Epithelium of aqueous humour . 513
Choroid. Blood-vessels of . . 514, 515
Tunica Euyschiana, vense vorticosa? . 515
Stellate choroidal epethelium . . . 515
Lamina fusca .... 516
Hexagonal choroidal epithelium . . 516
Tapetum lucidum .... 516
Ciliary and second ciliary processes . . 517
Zone of Zinn, iris, and uvea . . 517
Membrana pupilaris and retina . . 518
Tunica Jacob], granular and ganglionary layer 519
Vesicular, fibrous gray, and vascular ditto 520, 521
Optic nerves, vitreuus body, vitreous humour 521
Hyaloid membrane .... 521
Crystalline lens, capsule, body and fibres of 522
Structure and arrangement of ditto . . 522
Vogel. ' His opinion the mucous corpuscles are
formed externally to the blood-vessels . 177
Ditto as to the nature of pus and mucous
globules 184
On the stellate bodies observed on decompos-
ing fat vesicles .... 259
Volkman and Bidder. On the origin of gelatin-
ous filaments from the ganglia of the sym-
pathetic ..... 382
Wagner. On the blood of the lamprey . 91
His belief in the existence of a nucleus in the
red blood disc . . . .93
His opinion that the white globules are red
blood corpuscles in process of formation 112
On the milk globules . . .200
On the structure of human spermatozoa . 224
His supposition that the motions of spermato-
zoa were produced by a ciliary apparatus 226
His observation of spermatozoa" in motion at
the end of twenty-four hours . . 227
On the development of spermatozoa . . 229
On the degeneration of the testes of birds
during winter .... 232
i On spermatozoa in male hybrids . . 232
On the coloration of the iris of birds . 255
On the development of nerves . . 338
' Waller, Dr. A. On the tongue of the frog . 126
Williams. Dr. T. On the air cells of the lungs 396
Willis. His translations of Wagner's Physi-
ology ..... 388
Wilson, Mr. Erasmus. On the anatomy of epi-
dermis . . ... 280
On structure of the striated muscular fibrilla 358
Calculation of extent of sudoriferous system 438
Withoff. On the number of hairs existing on
different surfaces of the body . . 300
Young. His disbelief in the existence of a nu-
cleus in the red blood disc . . .93
Zinn. zone of
517
THE END
THE
MICROSCOPIC AIATOMY
OF
THE HUMAN BODY.
IN
HEALTH AND DISEASE.
ILLUSTRATED WITH NUMEROUS DRAWINGS IN COLOUR.
BY
ARTHUR HILL HASSALL, M. B.
Author of a "History of the British Fresh-water Alga;;" Fellow of the Linn;ean Society; Member of the
Royal College of Surgeons of England ; one of the Council of the London Botanical Society ;
Corresponding Member of the Dublin Natural History Society, &e.
ADDITIONS TO THE TEXT AND PLATES,
AND
AN INTRODUCTION,
CONTAINING INSTRUCTIONS IN MICROSCOPIC MANIPULATION,
BY
HENRY VANARSDALE, M, D.
IN TWO VOLUMES.
VOL. II.
NBW-YOEK:
PRATT, WOODFORD & CO.
BOSTON: T1CKNOR. REED, & FIELDS; PHILADELPHIA: LIPPINCOTT. GRAMBO & CO.
CINCINNATI: H. W. DERBY &. CO.; HARTFORD: E. C. KELLOGG.
1851.
ENTERED, ACCORDING TO ACT OF CONGRESS, IN THE YEAR 1851, BY
E. C. KELLOGG,
IN THE CLERK'S OFFICE OF THE DISTRICT COURT OF CONNECTICUT.
FOUNDRY OF PRESS OF
SILAS ANDRUS AND SON, F. C. GUTIERREZ,
HARTFORD. NEW-YORK.
INDEX OF THE ILLUSTRATIONS.
THE WHOLE OF THE FOLLOWING ILLUSTRATIONS ARE
ORIGINAL WITH BUT NINE EXCEPTIONS:
BLOOD.
Corpuscles of man, the red with the centres clear, 670 diam.
The same, the red with the centres dark, 670 diam.
The same, seen in water, 670 diam. .....
The same, the red united into rolls, 670 diam.
Tuberculated condition of the red corpuscles, 670 diam.
White corpuscles of man, in water, 670 diam.
Corpuscles of frog, 670 diam. ......
The same, with the nucleus of the red visible, 670 diam.
The same, in water, 670 diam. .....
The same, after prolonged action of water, 670 diam.
Nuclei of red corpuscles of frog, 670 diam.
Elongation of red corpuscles of ditto, 670 diam.
Corpuscles of the dromedary, 670 diam.
The same of the siren, 670 diam.
The same of the alpaco, 670 diam.
The same of the elephant, 670 diam.
The same of the goat, 670 diam.
Peculiar concentric corpuscles in blood, 670 diam.
Coagulated fibrin, 670 diam
The same with granular corpuscles, 670 diam.
Corpuscles of earth-worm, 670 diam.
Circulation in tongue of frog, 350 diam.
The same in web of the foot of ditto, 350 diam.
Corpuscles in vessels of the same, 670 diam.
White corpuscles in vessels of the same, 900 diam.
Glands of tongue of frog, 130 diam.
Under surface of tongue of same, 500 diam.
Red corpuscles of embryo of fowl, 670 diam.
The same, in water, 570 diam.
Red corpuscles of adult fowl, 670 diam.
The same of young frog, 670 diam.
The same of the adult frog, 670 diam.
The same united into chains, 670 diam.
Flute
I.
tig. 1
I.
« 2
I.
" 3
I.
« 4
I.
" 5
I.
" 6
II.
" 1
II.
" 2
II.
" 3
II.
" 4
II.
" 5
II.
« 6
III.
" 1
III.
« 2
III.
" 3
IV.
" 1
IV.
" 2
IV.
" 3
IV.
" 4
IV.
" 5
IV.
" 6
V.
" 1
V.
" 2
VI.
" 1
VI.
" 2
VII.
" 1
VII.
" 2
IX.
" 1
IX.
" 2
IX.
« 3
IX.
" 4
IX.
" 5
IX.
" 6
INDEX OF THE ILLUSTRATIONS,
DEVELOPMENT OF EMBRYO OF CHICK.
The cicatricula prior to incubation
The same at the end of first day of incubation
The same at the thirty-sixth hour .
The same at the close of the second day
The same at the end of the third day
The embryo on the conclusion of the fourth day
The same at the termination of the fifth day
The embryo of six days old ....
The embryo of the ninth day of development. .
The same at the end of the seventh day, detached
Ditto at the end of the ninth day, also detached
Plate
X.
Fig. 1
X.
" 2
X.
" 3
X.
" 4
X.
" 5
X.
" 6
X.
" 7
X.
" 8
X.
" 9
X.
" 10
X.
*< 11
MUCUS.
Corpuscles of, in their ordinary condition, 670 diam.
The same collapsed, 670 diam. .....
The same, showing the action of water, 670 diam.
The same acted on by dilute acetic acid, 670 diam.
The same after the action of undilute acetic acid, 670 diam.
The same in process of development, 670 diam.
Vaginal- mucus, 670 diam. . . • .
^Esophageal mucus, 670 diam. .....
Bronchitic ditto, 670 diam. . . . .
Vegetation in mucus, 670 diam. .....
Mucus of stomach, 670 diam
Vaginal tricho-monas .......
XI.
' 1
XI.
' 2
XI.
' 3
XI.
< 4
XI.
' 5
XI.
' 6
XII.
' 1
XII.
' 2
XII.
' 3
XII.
' 4
XII.
' 5
XII.
• G
PUS.
Corpuscles of laudable pus, 670 diam.
The same acted on by acetic acid, 670 diam.
The same treated with water, 670 diam.
Epithelial scales from pustule, 670 diam.
Corpuscles from scrofulous abscess, 670 diam.
Vibrios in venereal pus, 670 diam.
XIII.
' 1
XIII.
' 2
XIII.
' 3
XIII.
' 4
XIII.
' 5
XIII.
• 6
MILK.
Globules of healthy milk of woman, 670 diam.
The same of impoverished human milk, 670 diam.
Colostrum, 670 diam. .....
Ditto, with several corpuscles, 670 diam.
Globules-of large size, 670 diam.
Ditto, aggregated into masses, 670 diam.
Pus in the milk of woman, 670 diam.
Blood corpuscles in the human milk, 670 diam.
Globules after treatment by ether, 670 diam.
The same after the application of acetic acid, 670 diam
XIV.
' 1
XIV.
' 2
XIV.
' 3
XIV.
' 4
XIV.
' 5
XIV.
• G
XV.
■ 1
XV.
' 2
XV.
' 3
XV.
' 4
INDEX OF THE ILLUSTRATIONS. O
Caseine globules, 670 diam Plate xv. Fig. 5
Milk of cow adulterated with flour, G70 diam " xv. " 6
SEMEN,
Spermatozoa and spermatophori of man, 900 diam.
Spermatozoa of Certhia familiaris
FAT.
The fat vesicles of a child, 130 diam
Ditto of an adult, 130 diam.
Ditto or the pig, with apparent nucleus, 130 diam.
Ditto of the same, ruptured, 130 diam. ....
Ditto of marrow of the femur of a child, 130 diam. .
Ditto, with the membranes of the vesicles ruptured, 130 diam.
Crystals on human fat vesicles, 130 diam. ....
Fat vesicles in melicerous tumour, 130 diam.
Ditto contained in parent cells, 120 diam. ....
Ditto after the absorption of the parent cell-membrane, 120 diam.
XVI.
XVI.
XVIII.
" 1
XVIII.
« 2
XIX.
« 1
XIX.
« 2
XIX.
" 3
XIX.
" 4
XIX.
" 5
XIX.
" 6
LXIX.
" 10
LXIX.
« 11
EPITHELIUM.
Buccal epithelial cells, 670 diam.
Cuneiform ditto from duodenum, 670 diam.
Ciliary epithelium from trachea of frog, 670 diam.
Human ciliary epithelium from lung, 670 diam.
Ditto from trachea, 670 diam.
Tesselated epithelium from tongue of frog, 670 diam
Ditto from tongue of triton, 670 diam.
Ditto from serous coat of liver, 670 diam.
Ditto from choroid plexus, 670 diam.
Ditto from vena cava inferior, 670 diam.
Ditto from arch of the aorta, 670 diam.
Ditto from surface of the uterus, 670 diam. .
Ditto from the internal surface of the pericardium, 670 diam
Ditto of lateral ventricles of brain, 670 diam.
Ditto of mouth of menobranchus lateralis, 670 diam.
XX.
" 1
XX.
" 2
XXI.
" 1
XXI.
- 2
XXI.
" 3
XXI.
" 4
XXI.
" 5
XXII.
" 1
XXII.
" 2
XXII.
" 3
XXII.
" 4
XXII.
" 5
XXII.
" 6
XXVI.
" 6e
XXVI.
" 6d
EPIDERMIS
Upper surface of epidermis, 130 diam.
Under surface of ditto, 130 diam. ....
Epidermis of palm, viewed with a lens only,
Ditto, magnified 100 diam
Vertical section of ditto, 100 diam.
Ditto of one of the ridges, 100 diam.
Epidermis from back of hand, viewed with a lens
A portion of same more highly magnified, 100 diam.
Epidermis from back of hand 100 diam.
Ditto, viewed on its under surface, 100 diam.
Portion of ditto, with insertion of hairs, 100 diam.
XXIII.
< 1
XXIII.
• 2
XXIV.
• 1
xxiv.
' 2
XXIV.
' 3
XXIV.
' 4
XXIV.
' 5
XXIV.
' 6
XXVI. '
< 1
XXVI. '
' 2
xxvi. " 3
INDEX OF THE ILLUSTRATIONS,
Ditto from back of neck, 670 diam.
Detached cells of epidermis, 670 diam.
Cells of vernix caseosa, 130 diam.
Cells of ditto, 670 diam'.
NAILS.
Longitudinal section of nail, 130 diam
Ditto, showing unusual direction of stria?, 130 diam.
Ditto, with different distribution of striae, 130 diam.
Transverse section of nail, 130 diam. .....
Cells of which the layers are formed, 130 diam. and 670 diam.
Union of nail with true skin, 100 diam. ' .
. Plate xxvi. Fig. 5
" xxvi. "6a
" xxvi. "6b
" xxvi. "6c
" XXV.
' 1
" XXV.
< 2
" XXV.
' 3
" XXV.
' 4
" XXV. '
' 5
" XXVI.
' 4
PIGMENT CELLS.
Cells of pigmentum nigrum (human), 760 diam.
Ditto of the same of the eye of a pig, 350 diam.
Stellate cells of lamina fusca, 100 diam.
Ditto more highly magnified, 350 diam.
Cells of skin of negro, 670 diam.
Ditto from lung, 670 diam
Cells in epidermis of negro, 350 diam.
Ditto in areola of nipple, 350 diam. . .
Ditto of bulb or hair, 670 diam.
" XXVTI.
" 1
" XXVII.
" 2
" xxvii.
" 3
" XXVII.
"4a
" XXVII.
"4b
" XXVII.
"4 c
" xxvii.
" 5
" XXVII.
" 6
" XXVIII.
" 5
HAIR,
Bulb of hair, 130 diam
Root of a gray hair, 130 diam. . .
Cells of outer sheath, 670 diam
Portion of inner sheath, 350 diam.
Stem of gray hair of scalp, 350 diam.
Transverse section of hair of beard, 130 diam.
Another section of the same, 130 diam.
Fibres of the stem of the hair, 670 diam.
Apex of hair of perineum, 350 diam.
Ditto of scalp, terminating in fibres, 350 diam. .
Ditto of same with needle-like extremity, 350 diam.
Root of hair of scalp, 130 diam.
Another form of same, 130 diam. . . .
Hair with two medullary canals, 130 diam.
Insertion of hairs in follicles, 100 diam.
Disposition of hairs on back of hand.
CARTILA GE
Transverse section of cartilage of rib, 350 diam.
Parent cells seen in section of ditto, 350 diam.
Vertical section of articular cartilage, 130 diam.
Ditto of inter-vertebral cartilage, 80 diam.
Cartilage of concha of ear, 350 diam. .
XXVIII.
" 1
XXVIII.
" 2
XXVIII.
" 3
XXVIII.
" 4
XXIX.
" 1
XXIX.
" 2
XXIX.
" 3
XXIX.
" 4
XXIX.
" 5
XXIX.
" 6
XXIX.
" 7
XXTX.
( 8
XXIX.
" 9
XXIX.
' 10
XXVI.
' 3
XXIV. '
« 5
XXX.
' 1
XXX.
« 2
XXX.
' 3
XXX.
' 4
XXXI.
' 1
INDEX OF THE ILLUSTRATIONS
Cells of inter-vertebral cartilage, 350 diam.
Section of cartilage and bone of rib, 130 diam.
Ditto of one of the rings of the trachea, 350 diam.
Ditto of thyroid cartilage with fibres, 130 diam.
Cartilage of ossification, 100 diam.
Section of primary cancelli, 350 diam.
Ditto of same, more advanced, 350 diam.
Cartilage of ossification, 350 diam.
Section of cartilaginous epiphysis, 30 diam.
Ditto of same, with bone, 30 diam.
Ditto of same, more highly magnified, 330 diam.
Section of cartilage and bone of rib, 130 diam.
. Plate xxxi.
Fig
2
" XXXI.
c(
3
" XXXI.
"
4
" XXXI.
"
5
" XXXIV.
"
1
" XXXIV.
"
2
" XXXIV.
"
3
" XXXIV.
"
4
" XXXV.
"
1
" XXXV.
"
2
" XXXV.
"
.')
" XXXV.
"
6
BONE.
Transverse section of ulna, 60 diam.
Cross-section of Haversian canals, 220 diam.
Ditto of same more highly magnified, 670 diam.
Longitudinal section of long bone, 40 diam.
Parietal bone of foetus, 30 diam. . .
Portion of same more highly magnified, 60 diam.
Spicula of bone of foetal humerus, 350 diam.
Lamina of a long bone, 500 diam.
Cancelli of long bone of foetus, 350 diam.
Section of femur of pigeon fed on madder, 220 diam.
Section of epiphysis and shaft of foetal femur, 100 diam.
Transverse section of primary cancelli, 350 diam.
Section of cancelli more advanced, 350 diam.
Ditto of epiphysis and shaft of fetal femur, 350 diam.
Ditto of cartilaginous epiphysis of humerus, 30 diam.
Ditto of same with bone, 30 diam.
The same more highly magnified, 330 diam.
Blood-vessels and medullary cells ....
Section of shaft of fetal long bone, 20 diam.
Ditto of bone and cartilage of rib, 130 diam.
XXXII.
' 1
XXXII. '
« 2
XXXII. '
' 3
XXXII.
' 4
XXXIII.
' 1
XXXIII.
' 2
XXXIII.
' 3
XXXIII.
' 4
XXXIII.
< 5
XXXIII.
« 6
xxxiv.
' 1
XXXIV.
' 2
XXXIV.
' 3
XXXIV.
' 4
XXXV.
( 1
XXXV.
" 2
XXXV.
" 3
XXXV.
" 4
XXXV.
" 5
XXXV.
' 6
TEETH.
Vertical section of incisor tooth, seen with lens
Tubes of dentine near their termination, 670 diam.
A not unfrequent condition of same, 670 diam.
Tubes of dentine near their commencement, 670 diam.
Oblique section of tubes of dentine, 670 diam.
Transverse section of ditto, 670 diam. .
Transition of tubes into bone cells, 670 diam. .
Dilatation of ditto into bone cells, 670 diam.
Section of cementum, 670 diam. ....
Ditto of same traversed by tubes, 670 diam.
Ditto of same showing angular cells, 670 diam.
Fungus on section of dentine, 670 diam.
Oil-like globules on section of same, 350 diam.
XXXVI.
' 1
XXXVI.
« 2
XXXVI.
' 3
XXXVI.
< 4
XXXVI.
' 5
XXXVI.
' 6
XXXVI.
« 7
XXXVI.
' 8
XXXVII.
' 1
XXXVII.
' 2
XXXVII.
' 3
XXXVII.
' 4
XXXVII.
' 5
8
INDEX OF THE ILLUSTRATIONS,
Section of secondary dentine, 350 diam.
Ditto of bicuspid tooth, seen with lens only
Vertical section of enamel, 220 diam. .
Enamel cells seen lengthways, G70 diam.
Cross-section of cells of enamel, 670 diam.
Plate xxxvu. Fig. 6
" xxxvu. " 7
" xxxix. " 3
" xxxix. " 4
" xxxix. " 5
FIBROUS TISSUE,
Longitudinal section of tendon, 670 diam.
Transverse section of same, 670 diam.
White fibrous tissue, 670 diam.
Mixed ditto, 670 diam
Yellow fibrous tissue, 670 diam. .....
Different form of ditto, 670
Development of blood-vessels, 350 diam.
Areolar form of mixed fibrous tissue, 330 diam.
Blood-vessels of pia mater, 350 diam. ....
Development of white fibrous tissue, 670 diam.
Portion of dartos, 670 diam. -
Section of corpora cavernosa, slightly magnified .
XXXIX. '
< 1
XXXIX. '
< 2
xxxix. " 6
XXXIX.
' 7
XL.
' 1
XL.
' 2
XL.
' 3
XL.
« 4
XL.
' 5
XLIII.
" 2
XLIII.
' 3
XLIII.
" 4
MUSCLE.
Portion of striped muscle, 60 diam.
Fragment of unstriped ditto, 670 diam.
Muscular fibrillse of the heart, 670 diam.
Fragment of striped muscle of frog, 350 diam.
Fibres and fibrillae of voluntary muscle, 350 diam. .
Fibres acted on by acetic acid, 350 diam.
Ditto in different degrees of contraction, 350 diam.
Union of muscle with tendon, 130 diam.
Transverse section of muscular, fibres, 350 diam.
Fibres of voluntary muscle of fcetus, 660 diam.
Zigzag disposition of fibres, 350 diam.
Striped muscular fibre and fibrillae, 670 diam.
XLI.
' 1
XLI.
« 2
XLI.
' 3
XLI.
' 4
XLII.
• 1
XLII.
< 2
XLII.
< 3
XLII.
< 4
XLII.
• 5
XLIII.
' 1
XLIII.
" 5
XLIII.
" 6
NERVES,
Tubes of motor nerve, 670 diam
The same after the action of spirit, 670 diam.
The same after the action of acetic acid, 670 diam.
Portion of Casserian ganglion, 350 diam.
Nerve tubes of cerebellum, 670 diam.
Ditto of cerebrum, with clear cells, 670 diam.
Varicose condition of ditto, 670 diam.
Filaments of great sympathetic, 670 diam. .
Cells of gray matter of cerebellum, 670 diam.
Ditto of same, inner stratum, 670 diam.
Caudate ganglionary cells, 350 diam.
(Spinal cord, Medulla oblongata, Cerebellum.)
Ditto from locus niger of crus cerebelli, 350 diam.
XLIV.
' 1
XLIV. " 2
XLIV.
• 3
XLIV.
' 4
XLIV.
' 5
XLIV.
' 6
XLIV.
< 7
XLV.
' 1
XLV.
« 2
XLV.
" 3
XLV.
« 4
INDEX OF THE ILLUSTRATION
Ditto from hippocampus major, 350 diam.
Ditto from locus niger of crus cerebri, 350 diam. .
Pacinian bodies, natural size .....
Ditto, magnified 60 diam. .....
A single Pacinian body, 100 diam.
An anomalous Pacinian body ....
Two other anomalous Pacinian bodies
Cells from corpus dentatum of cerebellum, 350 diam.
Dlate xlv.
Fig
6
" XLV.
"
7
" XLVI.
"
1
" XLVI.
a
2
" XLVI.
"
3
" XLVI.
"
4
" XLVI.
"
5
" XLVI.
«
6
LUBJG,
Pleural surface of lung, 30 diam. ......
Ditto, with vessels of first order, 30 diam
Ditto, magnified 100 diam
Section of lung injected with tallow, 100 diam. .
Casts of air-cells, 350 diam
Section of lung injected with size, 100 diam.
Pleural surface of lung, with vessels of second order, 100 diam.
Section of lung, with air-cells uninjected, 100 diam.
Capillaries of lung, 100 diam.
XLVII.
' 1
XL VII.
' 2
XLVII. •
' 3
XLVIII.
' 1
XL VIII.
' 2
XLVIII.
' 3
XLIX.
' 1
XLIX.
« 2
XLIX.
' 3
GLANDS,
Follicles of stomach, with epithelium, 100 diam.
Ditto of large intestine, in similar condition, 100 diam
Ditto of same, without epithelium, 60 diam.
Termination of follicles of large intestine, 60 diam.
Follicles of Leiburkuhn in duodenum, 60 diam. .
Vessels of ditto of appendix vermiformis, 100 diam.
Ditto of same of stomach of cat, 100 diam.
Stomach tubes, cross-section of, 100 diam.
Longitudinal view of stomach tubes, 220 diam. .
Ditto of the same, 100 diam. ....
Villi of small intestine, with epithelium, 100 diam.
Ditto, without epithelium, showing lacteals, 100 diam.
Vessels of villi in duodenum, 60 diam.
Ditto of same in jejunum, 60 diam.
Ditto of same of foal, 60 diam. ....
Solitary glands of small intestine, natural size
Ditto of large intestine, slightly magnified .
Aggregated or Feyefs glands, 20 diam.
Side view of same, 20 diam
Sebaceous glands in connexion with hair, 33 diam.
Ditto from caruncula lachrymalis
An entire Meibomian gland, 27 diam. .
Illustrations of Mucous glands, 45 diam.
Farotid gland of embryo of sheep, 8 diam. .
Ditto of human subject, further developed, 40 diam.
Mammary gland, portion of, slightly magnified
Ditto of same, with milk globules, 90 diam.
L.
it
1
L.
tc
2
L.
"
6
L.
"
7
LII.
«
5
LI.
tc
1
LI.
ft
2
L.
"
3
L.
(C
4
L.
«
5
LII.
"
1
LII.
"
2
LI.
"
3
LI.
u
4
LI.
lxii.
"
5
6
LI.
«
6
LII.
"
3
LII.
"
4
LIII.
"
3
LIII.
"
1
LIII.
cc
2
LIII.
"
4
LIT.
"
1
LIV.
"
o
LIV.
"
5
LIV.
"
3
10
INDEX OF THE ILLUSTRATIONS,
Ditto of same more highly magnified, 198 diam.
Liver, section of, showing the lobules, 35 diam. .
Surface of ditto, showing the intra-lobular veins, 15 diam.
Section of liver showing the hepatic venous plexus, 20 diam
Vessels of portal system, 20 diam. ....
Section of liver, showing inter-lobular vessels, 24 diam.
Surface of liver, showing portal capillary system, 20 diam.
Ditto, showing both hepatic and portal venous systems, 20 diam
Ditto, with both systems completely injected, 20 diam
Ditto, with portal vein and hepatic artery, 18 diam.
A terminal biliary duct, 378 diam
Secreting cells of liver in healthy state, 378 diam.
Ditto, gorged with bile, 378 diam.
Ditto, containing oil globules, 378 diam.
Prostate gland, calculi of, 45 diam.
New tubular gland in axilla, 54 diam. . . •
Tubulus of ditto, 198 diam
Ceruminous glands, portions of, 45 diam. .
Sudoriferous gland, tubulus of, 198 diam.
Kidney, tubes of, with epithelium, 99 diam.
Cross-section of elastic frame-work, 99 diam. .
Ditto of frame-work and tubes, 99 diam. .
Section of vessels in tubular part of kidney, 33 diam.
The same vessels seen lengthways, 33 diam.
Tubes with epithelium, 378 diam ,
Corpora Malpighiana of kidney, injected, 40 diam.
Uriniferous tubes of a bird, 40 diam. ....
Corpora Malpighiana of the horse, 40 diam.
Inter- tubular vessels of surface of kidney, 90 diam.
Transverse section of injected kidney, 67 diam.
Uninjected corpora Malpighiana
With capsule, 100 diam
Without ditto, 100 diam. .
Malpighian body, more highly magnified, 125 diam.
Afferent and efferent vessels of Malpighian tuft, 45 diam.
Epithelial cells of the tubes, 378 diam.
Testis, tubes of, 27 diam
Tubes of ditto, more highly magnified, 99 diam.
Vessels of thyroid gland, injected, 18 diam. .
Vesicles of ditto, viewed with a lens only .
Ditto of same, magnified 40 diam. ....
Ditto of same, showing the structure of their walls, 67 diam
Lobes and vesicles of same in their ordinary condition, 27 di
Nuclei of vesicles of thyroid, 378 diam. ....
Follicles of thymus, with vessels, 33 diam.
Capsule of ditto, 54 diam
Nuclei and simple cells of same, 378 diam.
Compound or parent cells of ditto, 378 diam.
Spleen, nuclei and vessels of, 378 diam. .
Plate liv.
Fig. 6
" LIV.
" 4
" LV.
" 1
" LV.
" 2
" LV.
" 3
" LV.
" 4
" LV.
" 5
" LVI.
" 3
" LVI.
« 4
" LVI.
" 2
" LVII.
" 1
" LVII.
"2a
" LVII.
"2b
" LVII.
" 2c
" LVII.
" 3
" LVII.
" 4a
" LVII.
" 4b
" LVII.
" 5
" LVII.
" 4c
" LVIII.
" 1
" LVIII.
" 2
" LVIII.
" 3
" LVIII.
" 4
" LVIII.
" 5
" LVIII.
" 6
" LXIX.
" 1
" LIX.
" 2
" LIX.
" 3
" LIX.
" 4
" LIX.
" 5
" LX.
" 2
" "
" A
" "
" B
" LX.
"3a
" LX.
" 3b
" LX.
" 3o
" LX.
" 1
" LX.
" 4
" LXI.
" 1
" LXI.
" 2
" LXI.
" 3
" LXI.
" 4
" LXI.
" 5
" LXI.
" 6
" LXI.
<-• 7
" LXI.
" 8
" LXI.
" 9
" LXI.
" 10
" LXII.
" 1
INDEX OP THE ILLUSTRATIONS,
11
Supra-renal capsule, plexus on surface of, 54 diam. .
Tubes of ditto, 90 diam
Nuclei, parent cells, and molecules of ditto, 378 diam.
Vessels of supra-renal capsule, 90 diam.
Pineal gland, compound bodies of, 130 diam.
Pituitary gland, cells and fibrous tissue of, 350 diam.
Plate lxii. Fig. 2
LXII.
"3a
LXII.
" 36
LXII.
" 5
LXIX.
" 7
LXIX.
" 8
ANATOMY OF THE SENSE OF TOUCH.
Epidermis of palm of hand, 40 diam. ..... "
Ditto of back of hand, 40 diam. . "
Papillae of palm of hand, 54 diam "
Ditto of back of hand, 54 diam. ......."
Epidermis of palm, under surface of, 54 diam. .... "
Ditto of back of hand, under surface of, 54 diam "
Vessels of papilla? of palm of hand, 54 diam. .... "
Ditto of same of back of hand, 54 diam. ....."
lxiii.
' 1
LXIII.
' 2
LXIII.
' 3
LXIII.
< 4
LXIII.
' 5
LXIII.
' 6
LXIII.
« 7
LXIII.
< 8
ANATOMY OF THE SENSE OF TASTE,
Filiform papilla?, with long epithelial appendages, 41 diam.
Ditto, with shorter epithelial processes, 27 diam.
Ditto, without epithelium, near apex of tongue, 27 diam. .
Ditto, without epithelium, near centre of same, 31 diam.
Filiform and fungiform papillas, without epithelium, 27 diam.
Peculiar form of compound papillae, 27 diam.
Filiform papilla? in different states, 27 diam.
Ditto, with epithelium partially removed, 27 diam.
Follicles of tongue, with epithelium, 27 diam.
Ditto, without epithelium, 27 diam. ....
Ditto, viewed as an opaque object, 27 diam.
Filiform papilla? from point of tongue, 27 diam.'
Follicles and papilla? from side of ditto, 20 diam.
Simple papillae, with epithelium, 45 diam.
Filiform papillae, with ditto, 18 diam. ....
The same, viewed with a lens only ....
Side view of certain compound papilla?, 20 diam.
Simple papilla from under surface of tongue, 54 diam. .
Compound and simple ditto from side of tongue, 23 diam.
A calyciform papilla, uninjected, 16 diam.
Ditto, with the vessels injected, 16 diam. ....
Filiform papillae near centre of tongue, injected, 27 diam.
Ditto near tip of tongue, injected, 27 diam. . .
Simple papillae, injected, 27 diam. ....
Fungiform ditto, injected, 27 diam
"
LXIV.
" 1
if
LXIV.
" 2
"
LXIV.
" 3
"
LXIV.
« 4
it
LXIV.
" 5
it
LXIV.
" 6
"
LXIV.
« 7
ft
LXIV.
" 8
"
LXV.
" 1
"
LXV.
" 2
"
LXV.
" 3
ti
LXV.
" 4
it
LXV.
« 5
"
LXV.
" 6
it
LXV.
" 7
• \ "
LXV.
" 8
(f
LXV.
" 9
.
LXV.
" 10
"
LXV.
" 11
A
LXVI.
" 1
"
LXVI.
" 2
"
LXVI.
" 3
"
LXVI.
" 4
"
LXVI.
• 5
a
LXVI.
' 6
ANATOMY OF THE GLOBE OF THE EYE.
Vertical section of cornea, 54 diam.
A portion of retina, injected, 90 diam.
Section of sclerotic and cornea, 54 diam.
LXVII.
LXV1I.
LXVII.
12
INDEX OF THE ILLUSTRATIONS.
Vessels of choroid, ciliary processes, and iris, 14 diam
Nuclei of granular layer of retina, 378 diam.
Cells of the same, 378 diam
Ditto of vesicular layer of retina, 378 diam.
Caudate cells of retina, 378 diam. ....
Cells of the membrana Jacobi, 378 diam.
Fibres of the crystalline lens; a, 198 diam. ; b, 378 diam.
A condition of the posterior elastic lamina, 78 diam.
Peculiar markings on same, 78 diam.
Crystalline lens of sheep, slightly magnified
Fibres of lens near its centre, 198 diam. .
Stellate pigment in eye of sheep, slightly magnified
Vena? vorticosas of eye of sheep, injected
Conjunctival epithelium, oblique view of, 378 diam.
Ditto, front view of, 378 diam.
Ciliary muscle, fibres of, 198 diam.
Gelatinous nerve fibres of retina, 378 diam.
Cellated structure of vitreous body, 70 diam.
Fibres on posterior elastic lamina, 70 diam.
Portion of the iris, 70 diam.
Epithelium of crystalline lens, 198 diam. .
Ditto of the aqueous humour, 198 diam.
Hexagonal pigment of the choroid, 378 diam.
Stellate pigment of same, 378 diam. .
Irregular pigment of uvea, 378 diam.
Plate lxvii. F
ig. 4
" LXVII.
' 5
" LXVII.
' 6
" LXVII.
' 7
" LXVII.
' 8
" LXVII.
' 9
" LXVII.
' 10
" LXVII.
' 11
" LXVII.
' 12
" LXVII.
' 13
" LXVII.
' 14
" LXVIII.
' 1
" LXVIII.
« 2
" LXVIII.
' 3
" LXVIII.
< 4
" LXVIII.
' 5
" LXVIII.
< 6
" LXVIII.
' 7
" LXVIII.
« 8
" LXVIII.
' 9
" LXVIII.
« 10
" LXVIII.
' 11
" LXVIII.
' 12
" LXVIII.
' 13
" LXVIII.
' 14
AIAT0MY
OF THE
!0 diam.
NOSE.
Mucous membrane of true nasal region,
Ditto of pituitary region, injected, 80 diam.
Capillaries of olfactory region of human foetus, 100 diam.
LXIX.
" 1
LXIX.
" 2
LXIX.
" 12
ANATOMY OF THE EAR
Denticulate laminse of the osseous zone, 100 diam. .
Tympanic surface of lamina spiralis, 300 diam.
Inner view of cochlearis muscle of sheep .....
Plexiform arrangement of cochlear nerves in ditto, 30 diam.
VILLI.
Villi of foetal placenta, injected, 54 diam.
Ditto of choroid plexus, 45 diam.
LXIX.
' 3
LXIX.
< 4
LXIX.
' 5
LXIX.
' 6
LXII.
• 4
LXII.
' 9
Plates VIII., XVIL, and XXXVIII., omitted in the original edition, are likewise
nere omitted. The same numbers for the other plates are observed, that the figures
in both editions may correspond.
The Plates added to the American Edition commence at Plate LXX.
PLATES ADDED
THE AMERICAN EDITION
Corpuscles of lymph, 800 diam.
Corpuscles of chyle, 800 diam.
Fat vesicles, injected, 45 diam. ....
Transverse sections of hair, 450 diam.
Cartilage from finger-joint, 80 diam. .
Vessels of synovial membrane, 45 diam. .
Injected matrix of finger-nail, 10 diam.
Vessels of tendon, 60 diam. .....
Ditto nearer muscular union, 30 diam.
Lymphatic gland and vessels, 8 diam. ...
Capillaries and air-cells of fcetal lung, 60 diam. .
Ditto of same of child, 60 diam. ....
Ditto of same of adult, 60 diam.
Braiichia of an eel, 60 diam. .....
Mucous membrane of fcetal stomach, 60 diam.
Ditto, showing cells and cap. ridges of adult, 60 diam.
Ditto with cells deeper and ridges more elevated, 60 diam
Ditto showing gastric villi, 60 diam.
Villi of duodenum, 60 diam. ....
Ditto of jejunum, 60 diam. ....
Ditto of ileum, 60 diam
Muscular fibre of small intestine, 60 diam.
Appendix vermiformis, 60 diam.
Mucous follicles of colon, 60 diam.
Malpighian bodies with uriniferous tubes, of adult, 100 diam.
Ditto enlarged as in Blight's disease, 100 diam.
Enlarged veins of kidney, first stage of Bright's disease,
Ditto of same, another view, 100 diam.
Stellated veins in third stage of same, 100 diam.
Granulation on the surface of kidney, 100 diam.
A tube much dilated, 100 diam. ....
Sudoriparous glands and their ducts, 70 diam.
Ditto, more highly magnified, 220 diam.
100 diam.
?la
>e lxx.
Fig. 1
"
LXX.
" 2
"
LXX.
" 3
SS
LXX.
" 4
tt
LXX.
" 5
tt
LXX.
" 6
«
LXXI.
"
SS
LXXII.
" 1
St
LXXII.
" 2
"
LXXIII.
" 1
tt
LXXIII.
" 2
te
LXXIII.
" 3
SS
LXXIII.
« 4
ts
LXXIII.
" 5
St
LXXIV.
" 1
"
LXXIV.
" 2
tt
LXXIV.
" 3
"
LXXIV.
" 4
"
LXXIV.
" 5
"
LXXIV.
" 6
tt
LXXV.
" 1
tt
LXXV.
" 2
"
LXXV.
" 3
"
LXXV.
" 4
"
LXXV.
" 5
"
LXXV.
" 6
tt
LXXVI.
" 1
«
LXXVI.
" 2
ft
LXXVI.
" 3
"
LXXVI.
" 4
tt
LXXVI.
" 5
tt
LXX VII.
" 1
«
LXXVII.
« 2
14 INDEX OF THE ILLUSTRATIONS.
Mucous membrane of gall-bladder, 50 diam Plate lxxvii. Fig. 3
Transverse section of muscles of the tongue, 45 diam. ..." lxxvii. " 4
Terminal vessels in cornea, 45 diam. ..... " lxxviii. " 1
Cornea of viper, showing its vessels, 45 diam. " lxxviii. " 2
Choroid coat of foetal eye, 45 diam. ....... " lxxviii. " 3
Ciliary processes of eye of adult, 45 diam. ....." lxxviii. " 4
Mucous lining of unimpregnated uterus, 35 diam. ... " lxxviii. " 5
Ditto of impregnated uterus, 35 diam " lxxviii. " 6
Tuft of placenta, 60 diam. " lxxix. " 1
Papillae of gum, 45 diam " lxxix. " 2
Ditto of lip, 45 diam " lxxix. " 3
Blood-vessels in mucous membrane of trachea, 45 diam. . . " lxxix. " 4
Ditto of buccal membrane, 60 diam. " lxxix. " 5
Ditto of mucous membrane of bladder, 60 diam " lxxix. " 6
EXPLANATION OF THE PLATES
PLATE I.
The figures in this plate are magnified 670 diameters.
THE BLOOD OP MAN.
Fig. 1. The human red blood corpuscle, showing its natural form
and appearance when brought fully into focus, in which
case the centre always appears light. Scattered over the
field will be seen one or two white corpuscles.
2. The same, with the centre dark, in consequence of the object
not being brought fully into focus.
3. The same in water, in which the red globules lose their flat-
tened and discoidal form, becoming circular, and presenting
a smaller surface to view; the white corpuscles at the same
time, and under the influence of the same agent, are seen
to have increased considerably in size.
4. The same, united into rolls, as of miniature money in
appearance.
5. The same, showing the peculiar granulated and vesiculated
appearance which they so frequently present under such
different circumstances.
6. The white corpuscles of the blood, in water, in which they
enlarge considerably in dimensions, often appear nucleated,
and after long immersion, burst.
Plate I.
H.MlliMiel
E.CKtllodg.lith.
18 EXPLANATION OF THE PLATE
PLATE II,
The figures in this plate are magnified 670 diameters.
THE BLOOD OF THE FROG.
Fig. 1. The blood corpuscle of the frog, both red and white, with
the nucleus of the former seen indistinctly.
2. The same, with the nucleus distinctly visible, the difference
arising from the greater length of time during which the
latter has been removed from the system.
3. The same, in water, showing the change of form which the
red blood corpuscle, as well as its contained nucleus, under-
goes in that fluid, and also the enlargement of the white
corpuscles.
4. The same, showing the effect of the prolonged action of water
on the red corpuscles; the nuclei are now not merely
circular, but most of them have become eccentric, and
certain of them have escaped altogether from the mem-
branous capsular portion of the corpuscles, which and the
nuclei are seen lying side by side as distinct structures.
5. The nuclei, separated from the capsule by the action of
acetic acid.
6. Shows the extraordinary deformity and elongation of which
the red blood corpuscles are susceptible when subject to
any extending force, or even to lateral pressure. In the
figure, the extension has been exerted on the corpuscles by
means of the filaments which fibrin in coagulating runs into,
and a portion of one of which may be seen uniting the
corpuscles.
3
PLccte II
Miller del
E.C.KelLoPS.lith
20 EXPLANATION OF THE PLATES,
PLATE III.
The figures in this plate are magnified 670 diameters.
For the blood from which the figures contained in this plate were
made, as well as some of those of the following plate, I am indebted
to the kindness of Mr. Ogilby, the Secretary of the Zoological Society,
who, on my application to him, promptly and courteously forwarded
to me the permission requisite to enable me to obtain it.
Fig. 1. The red and white blood corpuscles of the dromedary; in
water, the former became perfectly spherical.
2. The same, of the Siren.
3. The same, of the Alpaco.
Plate III.
f\ t .
1
• -J
■■
■' f 1 v
-
3w
■ x
-
gj .
v
fe^
/
\
rtf
A
/
E Miller del.
E.C.K&lloes.Mi.
EXPLANATION OF THE PLATES. , 21
PLATE IV,
The figures in this plate are magnified 670 diameters.
Fig. 1. Represents the blood corpuscles of the elephant, red and
white, which are the largest hitherto discovered among the
mammalia.
2. Exhibits the blood corpuscles of the goat, both red and white,
which are among the smallest as yet made known in the
class to which they belong.
3. Peculiar concentric corpuscles, taken twenty-four hours after
death from a polypus contained in the heart of an old man.
4. A portion of fibrin, removed from a small cavity situated
beneath the buffy coating formed on some blood which had
been abstracted from a woman, the subject of epileptic fits,
and for which she was bled; it exhibits the granular and
fibrous structure, which the spontaneously coagulable
element of the blood invariably assumes in solidifying.
5. A portion of fibrin, constituting the buffy coat, and which
formed a thick membrane on the surface of the blood
abstracted from the woman already alluded to; it exhibits
more clearly the fibrous construction of the fibrin, the fibres
being rendered more apparent by the action of corrosive
sublimate, and also some of the white corpuscles which are
found usually in such abundance in the so-called inflamma-
tory crust. All false membranes have a constitution pre-
cisely similar.
6. Blood corpuscles of the earth-worm in various states ; those
contained in the lower half of the circle represent them as
they appear in the liquor sanguinis, or plasma, in which
most of the corpuscles speedily assume a stellate form, as
do those of most of the invertebrate animals, and in which
state they bear a close resemblance to the hispid pollen
granules of the order Composite; the stellate form of the
22 EXPLANATION OF THE PLATES.
corpuscles is speedily followed by their considerable enlarge-
ment, rupture, and disaggregation; the corpuscles repre-
sented in the upper half of the circle have been acted upon
by water, in which they quickly lose their radiate aspect,
swell, increase to two or three times their original dimen-
sions, exhibit their contained molecules more clearly, and
which may frequently be seen in a state of the greatest
activity ; finally, the corpuscles become deformed in shape
and burst. It may here be remarked, that the blood of
most of the Invertebrata is colourless, arising from the fact
of their blood containing but one form of corpuscle, the
colourless blood corpuscle. In the Annelida, indeed, the
blood is red ; the colouring matter, however, is not contained
in the corpuscle, but in the plasma.
Flajte- IV.
S.Miller, del.
E.C.Ivellogo.lith.
24 EXPLANATION OF THE PLATES.
I
PLATE V.
The figures in this plate are magnified 350 diameters.
1. Exhibits the circulation in a portion of the tongue of the
frog, the larger vessel is seen to be accompanied by a nerve,
as is usually the case, and in all the vessels are shown the
red and white corpuscles, with their differences of form, size,
structure, colour, and position; the general direction and
appearance of the muscular fibres, are likewise indicated.
2. Represents the distribution of the smallest capillaries in the
web of the foot of the frog, in which it is seen that the
blood corpuscles circulate only in sing^- series, the pigment
cells, cellular tissue of the parenchyma, and the beautiful
hexagonal and nucleated tessellate epidermis are likewise
exhibited.
PlaU V.
H. Miller, del.
EC. Kellogg ltth.
26 EXPLANATION OF THE PLATES.
PLATE VI.
Fig. 1. Is a more highly magnified representation of the circulation
in the capillaries of the web of the foot of the frog; in it
the white and red corpuscles as well as the epidermis are
more clearly defined ; two of the white corpuscles are seen
to be of an oval form, resulting from compression between
the red blood discs and the walls of the vessels. This figure
is magnified 670 diameters.
2. Exhibits a portion of a larger vessel also taken from the web
of the foot of the frog ; in it the white corpuscles are seen to
have collected in considerable quantity, as they are fre-
quently observed to do after long exposure of the web to
the action of the air; two cells or globules of a very peculiar
structure are likewise figured ; these open on the surface,
and possibly are mucous » crypts. This representation is
magnified 900 diameters.
4
Plate, VI.
H Miliei ael
:>:.:;: lifh
28 EXPLANATION OF THE PLATES.
PLATE VII.
Obs. — It is scarcely necessary to observe, that the comparative
anatomy figures are introduced in this work for the purpose of illus-
trating, in a more satisfactory manner than could be otherwise
accomplished, certain points, especially the more obscure ones, con-
nected with human anatomy.
These figures should, therefore, by no means be regarded as taking
the place of any of those which should illustrate human anatomy, and
not one of which, deemed to be of importance, will on any account
be omitted; they should be deemed not as substitutes, but as additions
to the original design of the work, and which cannot but enhance
very considerably its value.
Fig. I. Represents a portion of the under surface of the tongue of the
frog, magnified 130 diameters, and on which are seen, first,
numerous glands, mostly spherical, and traversed by a tor-
tuous vessel, in which the blood corpuscles are tossed about
as it were in a vortex ; and, second, mucus crypts, the
apertures of which are apparent. Donne has observed these
bodies, but believes them to be formed by nervous loops, and
appears to have overlooked the orifices alluded to: these I
found to be figured in a drawing of the tongue of the frog,
sent me by Dr. Waller, but unaccompanied by any
explanation.
Fig. 2. A portion of the same, magnified 500 diameters, showing the
incurrent and excurrent vessel of the gland, the mucous
crypts, and the net-work formed by the epithelium.
Plate VII.
H Miller
E.C Kellogg Mh
EXPLANATION OF THE PLATES,
29
PLATE IX.
The figures in this plate are magnified 670 diameters.
DEVELOPMENT AND DISSOLUTION OE THE RED BLOOD CORPUSCLE,
Fig. 1. Represents the development of the red blood corpuscle of the
embryo fowl, on the third day of its growth, obtained from
one of the vessels of the area vasculosa: this is seen to be of
many different sizes, the smaller being scarcely a third the
volume of the larger discs, and consisting of but little more
than a nucleus and an envelope. Numerous molecules are
likewise visible, scattered over the field.
Fig. 2. The same, in water.
Fig. 3. The red blood corpuscles of the adult fowl, mostly in different
stages of dissolution ; the larger and deeply coloured cor-
puscles represent the fully-developed discs ; the larger and
pale ones, with the distinct nuclei, those the dissolution of
which has just commenced ; the smaller and colourless ones,
red blood discs in advanced stages of dissolution, the sole
remains of which at length is the nucleus, also represented
in the figure.
Fig. 4. The red blood corpuscle of the young frog in different stages
of development. First, it is seen as a small and granular
body of a circular form ; secondly, it assumes an oval shape,
but still retains its granular constitution, and but little exceeds
its former dimensions. In this its second stage of develop-
ment, it is still colourless : it soon, however, grows in size,
and acquires a greater or less degree of colouration ; so that
when it has attained one-half or two-thirds of its size, it is
nearly as deeply coloured as the full-grown blood disc : the
colourless granular nucleus and the coloured and perfectly
smooth outer portion of each globule are not at first distinctly
30 EXPLANATION OF THE PLATES.
separated from each other, the former being at its origin
rather large, and without any defined margin: it soon, how-
ever, shrinks in size, and assumes a regular oval shape.
Crescentic bodies, occasionally met with in the blood of the
frog, and probably of vegetable nature, are also represented
in the figure.
Fig. 5. The red blood corpuscle of the adult frog, in different stages
of dissolution. In examining a drop of the blood of a full-
grown frog, a much greater uniformity in the size of the red
blood discs will be observed, than exists in that of the very
young animal, fewer corpuscles being in process of develop-
ment in the former than in the latter.
Fig. 6. Blood corpuscles of the adult frog united into chains, an
arrangement which appears to be intimately connected
with the coagulation of the fibrin.
Fleets IX.
H Miller. del.
E-CK.ello64.hth.
EXPLANATION OF TOE PLATES. 31
PLATE X.
The figures in this plate are magnified 670 diameters.
DEVELOPMENT OF THE EMBRYO OE THE CHICK
Fig. 1. The appearance of the cicatricula in the yolk prior to
incubation.
Fig. 2. The same at the end of the first day of incubation ; the halones
are now distinctly visible, as also the area pellucida, and
nota primitiva, or first rudiment of the young chick.
Fig. 3. The same at the termination of the thirty-sixth hour of incu-
bation ; the halones have become more marked and expanded,
the nota primativa larger, and traces of blood-vessels are
now for the first time distinctly visible in the germinal
membrane.
Fig. 4. The same at the close of the second day; the pulsation of the
heart and the vessels of the area vasculosa are clearly visible ;
within them the coloured corpuscles may be seen circulating.
Fig. 5. The same at the end of the third day of development; the
area vasculosa has now extended itself to two or three times
its former dimensions.
Fig. 6. The embryo on the conclusion of the fourth day; the head,
the eye, and the budding of the allantois are now seen in
addition to the parts previously noticed.
Fig. 7. The embryo at the termination of the fifth day ; the wing and
the foot have made their appearance; the limits of the area
vasculosa cannot now be seen, it extending over two-thirds
of the surface of the egg; after this and the following day,
the periods of its complete development, the area suffers an
arrest of growth, and the vessels contract and carry but
little blood, until at length they are entirely obliterated.
The allantois has on this day attained a considerable size,
and its further growth proceeds with the utmost rapidity.
32 EXPLANATION OF THE PLATES.
Fig. 8. The embryo six days old with the allantois separated from
the area vasculosa and the yolk, &c.
Fig. 9. The embryo of the ninth day of development, seen through
the allantois, which now invests nearly the entire surface
of the yolk, and beneath which the collapsed and faintly
coloured vessels of the area vasculosa may still be discerned.
The purpose fulfilled by the distribution of such innumerable
vessels in the membrane of the area vasculosa, and subse-
quently in the allantois, is but temporary, and is doubtless
connected with respiration, the blood in these vessels being
submitted to the influence of the oxygen of the air, which
enters the egg through the pores contained in its shell; the
vital fluid is thus regenerated and afterwards reconveyed to
the embryo itself, from which it first proceeded. At the
completion of the development of the chick, the allantois
undergoes the same obliteration of its vessels which the area
vasculosa previously suffered.
Fig. 10. The embryo at the end of the seventh day of development
removed from its membranes.
Fig. 11. The same at the end of the ninth day, also separated from
its membranes.
Such is a brief sketch of the marvellous development of the embryo
of the chick.
Plzte, X.
Ji. Killer, del.
E.C Hello gg.Iith
34 EXPLANATION OF T U E PLATES,
PLATE XI.
The figures in this plate are magnified 670 diameters.
MUCUS.
Fig. 1. Mucus corpuscles of their ordinary size, form, and appearance.
Fig. 2. The same collapsed, owing to the density of the fluid in which
they are contained; these corpuscles are capable of resuming
the circular form by the addition of water.
Fig. 3. Represents the action of water on the mucus corpuscles, in
which they increase very considerably in dimension, the
nucleus which is usually single becoming at the same time
more distinct.
Fig. 4. The same acted on by very dilute acetic acid, under the
influence of which the originally single nucleus becomes
divided into two parts, the portion of the corpuscle external
to these remaining granular.
Fig. 5. Exhibits the action of undilute acetic acid, under which the
nucleus becomes divided into from two to five or even more
parts, the enveloping portion of the corpuscle losing its
granular texture, and appearing perfectly smooth and
transparent. '
Fig. 6. Mucus corpuscles in process of development, expressed from
the cavity of a gland situated in the mucous membrane
lining the upper portion of the rectum of a child who died
of English cholera.
Fh/< Jl.
H.Miller, del.
E.C.Ivelloa§.litli.
EXPLANATION OF TH.E PLATES,
PLATE XII.
The figures in this plate are magnified 670 diameters.
MUCUS.
Fig. 1. Represents an example of vaginal mucus obtained during
parturition, and containing blood corpuscles.
Fig. 2. Is a representation of oesophageal mucus.
Fig. 3. Exhibits the mucous corpuscles contained in some bronchitic
mucus, and obtained from a patient labouring under chronic
bronchitis. The mucus was ropy and tenacious, and many
of the corpuscles were rendered of an oval form by the
pressure exerted upon them by the filaments, of which the
fluid portion of true mucus is constituted.
Fig. 4. Vegetation contained in the same mucus as that from which
the previous figure was made.
Fig. 5. Mucus from the stomach.
Fig. 6. Is a representation of the vaginal tricho-monas of Donne\
copied from the atlas appended to the "Cours de Micro-
scopie."
It may here be observed that the above is the only instance of a
copied figure being introduced into this work, and that in no case
where it is possible to procure subjects for original drawings, will
copied ones be admitted.
'Plate XII.
H M ller.del
E.C.Kellogg.litL
38 EXPLANATION OF THE TLATEB
PLATE XIII.
The figures in this plate are magnified 670 diameters.
PUS.
Fig. 1. Is a representation of an example of laudable pus formed on
a granulating surface on the arm of a child, the consequence
of a burn. In this figure, one or two oil globules are likewise
introduced.
Fig. 2. The same acted on by acetic acid, and showing the compound
nuclei.
Fig. 3. Pus corpuscles treated with water, many of them exhibiting
but a single nucleus. This example of pus was obtained
from a pustule formed around the root of the nail, and induced
by a prick received during dissection.
Fig. 4. Epithelial scales remarkable for the great size of their nuclei,
and obtained from a small pustule situated beneath the nail
of one of the fingers, and which pustule was also the result
of a prick received in dissecting.
Fig. 5. An example of pus obtained from an old scrofulous abscess :
the corpuscles in it are seen to be mostly broken up into the
primary molecules of which they are constituted.
Fiff. 6. An example of venereal pus, showing the peculiar animalcules
described by Donne.
The whole of the figures contained in this and the two preceding
j 'lates illustrate human microscopic anatomy.
T Late XIII.
H.Miller ael.
EC.Xelloed.lith.
40 EXPLANATION OF THE PLATES,
PLATE XIV.
The figures in this plate are magnified 670 diameters.
MILK.
Fig. 1. The globules of the healthy milk of a woman.
Fig. 2. The globules contained in impoverished human milk, which
are seen to be smaller in size and fewer in number than in
ordinary milk.
Fig. 3. An example of colostrum, on the first day, obtained from a
young woman aged nineteen, delivered of her first child, and
showing the size and arrangement of the ordinary milk glob-
ules, as well as the structure and appearance of the peculiar
colostrum corpuscles.
Fig. 4. The same colostrum of the same age, containing a greater
number of the colostrum corpuscles.
Fig. 5. The same colostrum, on the same day, exhibiting the great
size of the cream globules, which appear frequently to pre-
sent rather the aspect of oil than that of true milk globules.
Fig. 6. The milk globules aggregated into masses, as occurs in cases
of engorgement of the breast.
7CLt& XIV.
42 EXPLANATION OF THE I' L A T E 8 ,
PLATE XV.
The figures in this plate are magnified 670 diameters.
MILK.
Fig. 1. An example of pus in the milk of woman.
Fig. 2. The same of the blood corpuscles in human milk.
Fig. 3. The appearance of the milk after treatment by ether.
Fig. 4. The same after the application of acetic acid.
Fig. 5. Caseine precipitated from the filtered serum by acetic acid.
Fig. 6. A specimen of the milk of the cow in which adulteration with
starch was revealed by treatment with the iodide of potassium.
For many of the examples of human milk upon which my observa-
tions were made, and from which several of the figures were prepared,
I am indebted to the kindness of Dr. Robert Barnes, District Surgeon
to the Queen Adelaide Lying-in Hospital.
6
Plate, XK
H.liiilev.dei.
E.C.KeHoPB.lith.
44 EXPLANATION OF r H E PLATES
PLATE XVI.
SEMEN.
Fig. 1. The spermatic animalcules and "seminal granules ,; contained
in the human semen as ejaculated, magnified 900 diameters,
and to which are added several sperm atophori, magnified to
the same extent, and introduced to render the representation
of the development of the spermatozoa of man more com-
plete. The larger seminal granules mostly contained a
single distinct nucleus, which renders it probable that they
are spermatophori in progress of development.
Fig. 2. Represents the several stages of evolution of the spermatic
animalcules of certhia familiaris (common creeper) ; I, an
adult spermatozoon, taken from the orifice of the vas defer-
ens ; a. seminal granule, procured from a very collapsed
testicle in the winter season ; b to k. spermatophori in differ-
ent stages of development, taken from a testicle in summer,
during turgescence. Magnified 900 diameters.
This figure is copied from Wagner's " Elements of Special
Physiology."
Tla/r XVI.
S Miller del.
E.CKeL
46 EXPLANATION OF THE PLATES,
PLATE XVIII.
The figures in this plate are magnified 130 diameters.
FAT.
Fig. 1. A portion of the great omentum of a child aged seven years.
The fat cells are seen to be small, perfectly globular, and
aggregated into clusters, which lie near to and in the course
of the blood-vessels.
Fig. 2. A portion of the fat of an adult taken from over the gluteus
muscle. The fat cells in it are observed to be of larger
size, and many of them are polyhedral ; these cells are also
seen to be held in union by an enclosing membrane of cellu-
lar tissue.
Plate ZV1II.
E Miller, del.
E.C.Kello^.lith.
48 EXPLANATION OF THE PLATES.
PLATE XIX.
The figures in this plate are magnified 130 diameters.
PAT.
Fig. 1. Fat vesicles of the pig, in which the appearance of a nucleus
was produced by moderate compression between two plates
of glass.
Fig. 2. The fat vesicles of the pig, ruptured by compression between
two plates of glass: the contents of the cells are seen
escaping from their enclosing membranes.
Fig. 3. Fat cells, forming part of the marrow contained in the femur
of a child aged about ten years; in these a large nucleus-like
body is visible, the formation of which probably depended
upon a change in the condition of the contents of the cells
induced by decomposition.
Fig. 4. The same cells in a further stage of decomposition: the
membranes of the cells have become ruptured, and are
clearly seen broken and empty, lying beside their escaped
contents, which either become broken up, and assume the
form of drops of oil of different sizes, or remain entire, in
which case they frequently exhibit the crystalline appearance
portrayed in figure 5.
Fig. 5. Human fat vesicles, on the surface of which crystals, supposed
to be those of margaric acid, radiating from a centre, have
appeared : their presence is to be regarded as an indication
that decomposition has begun to affect the contents of the
cells.
Fig. 6. Fat cells, contained in a small melicerous tumour removed
from over the nasal bones, in all of which a nucleus-like
body was clearly visible.
The tumour from which the figure was taken was kindly forwarded
for examination by Mr. Ransom, of the University College Hospital.
Plate XIX.
H Miller del.
£ C.Kellog§,lifll.
50 EXPLANATION OF THE PLATES
PLATE XX.
The figures in this plate are magnified 670 diameters.
Fig. 1. Buccal epithelial cells in different stages of development, from
their earliest condition, in which they bear the form of
mucous corpuscles, to their fully developed state. For a
representation of the epithelial cells of the vagina and
oesophagus, see Plate ^Lll.figs. 1 and 2.
Fig. 2. Cylindrical or cuneiform epithelial cells, taken from the duode-
num of a child seven days old : those of the adult are in
every respect identical; the group of angular cells at the
inferior part of the figure represents the summits of the
cuneiform epithelial cells.
7
FlateXX.
filler del.
E.C Kellosje.lith.
EXPLANATION OF THE PLATES. 51
PLATE XXI.
The figures in this plate are magnified 670 diameters.
Fig. 1. Ciliary epithelium from the trachea of the frog: it will be seen
that the form of the cells is very different from that of
mammalia.
Fig. 2. Human ciliary epithelium contained in the fluid expressed
from a portion of lung taken from its extreme periphery,
and apparently consisting of air cells alone. It is mixed up
with cells of tesselated epithelium.
Fig. 3. Human ciliary epithelium from the trachea; both side and
end views of the cells are given.
Fig. 4. Tesselated epithelium from the tongue of the frog.
Fig. 5. Tesselated epithelium from the tongue of the Triton: the
nuclei are seen to be very large, their great size affording an
illustration of the law which has already been announced,
viz: that all the corpuscular elements of the animal organi-
zation, whether those of the epithelium, the glands, cartilages
or muscles, stand in relation with the dimensions of the blood
discs; where these are large, ihe other corpuscles are formed
on a similar relative scale.
It is probable that the law admits of extension, and that all the elements
of the animal structure bear a relation in size to the red blood discs.
Mr. John Quekett made the interesting observation, some time since,
that the relative size of the lacunaB of bone corresponded with that
of the blood corpuscles, a further illustration of the accuracy of the
law referred to.
Wishing to test the truth of this law in as satisfactory and conclu-
sive a manner as possible, I applied to Professor Owen for a specimen
52 EXPLANATION OF T li E I' L A T E S .
of the Siren or Proteus, animals remarkable for the dimensions of
their blood discs, and that gentleman kindly placed at my disposal an
example of the Meno-branchus lateralis, a member of the same
perenni-branchiate group, and the blood corpuscles of which "are
rather larger than those of the Proteus, but not so large as those of
the Siren." In this animal I found, as I had anticipated, that the
soundness of the law was fully maintained.
The law announced would doubtless be cited by those physiologists
who enterts:n the idea that all the corpuscular elements of the animal
fabric proceed from the red blood disc, as a proof of the truth of their
theory, against which, however, I conceive that sound and conclusive
arguments may be urged.
PI a/ r- XXI.
TT.Miller.de!.
E.G.T(e]lo66.1itli.
54 EXPLANATION OF THE P L A T E S ,
ALL THE FIGURES IN THIS PLATE ARE HITMAN.
PLATE XXII.
The figures in this plate are magnified 670 diameters.
Fig. 1. Tesselated epithelium from the serous coat of the liver; from
some of the cells the nuclei have escaped.
Fig. 2. Ditto from the choroid plexus ; the spines described by Henle
as proceeding from the angles of the cells must be of unusual
occurrence, as I have never yet seen them.
Fig. 3. Ditto from the vena cava inferior in different stages of devel-
opment, from the white corpuscle of the blood upwards.
Fig. 4. Ditto of the arch of the aorta; some of the cells are seen to
have lost their nuclei.
Fig. 5. Ditto from the surface of the uterus of a woman who died
suddenly during lactation.
Fig. 6. Ditto from the internal surface of the pericardium.
PhuXKIT.
H.MfllKi-.iiel.
— Kellood. lith.
56 EXPLANATION OF THE PLATES.
PLATE XXIII.
Fig. 1. Upper surface of epidermis, raised by means of a blister
from over the region of the heart of a woman : it exhibits
the cellular constitution of the epidermis, the papillae and
apertures of the sebaceous and sudoriferous glands. 130
diameters.
Fig. 2. The under surface of the same, exhibiting the infundibuliform
processes of the epidermis sent down to the sebaceous and
sudoriferous glands. 130 diameters.
Flate XXIII.
H Miller, del.
3. C.Kello^ Mi.
58 EXPLANATION OF THE PLATES.
PLATE XXIV.
STRUCTURE OF EPIDERMIS.
Fig. 1. A portion of the epidermis of the palm of the hand, magnified
with a simple lens, showing the direction of the rugae in
that situation, and the arrangement of the apertures of the
sudoriferous glands. Each of the ridges figured is made up
of square compartments, the divisional lines of which run at
right angles to the ridges, passing across the apertures referred
to. These several compartments again are indented on their
under surface with the papillae of the sensitive skin.
Fig. 2. A portion of the same, magnified 100 diameters.
Fig. 3. A transverse section of the ridges of the epidermis of the palm
of the hand, showing a side view of the apertures of the
sudoriferous glands, their spiral ducts, the thickness of the
epidermis in the situation mentioned, its composition of
super-imposed layers of cells, and its mode of connexion
with the true skin. 100 diameters.
Fig. 4. A longitudinal section of one of the ridges, magnified to the
same extent as the previous figure, viz: 100 diameters: in
this the composition of the thickened epidermis of adherent
layers of cells is better seen, and the difference in the form
of the superficial and deeper seated cells may also be
observed.
Fig. 5. A portion of the epidermis removed from the back and outer
part of the hand, showing the disposition of the folds in that
situation, the arrangement of the papillae, the disposition of
the hair follicles and hairs, and the apertures of the sudorif-
erous and sebaceous glands. Magnified with a simple lens.
Fig. 6. A piece of the same, magnified 100 diameters, showing that
each line is a furrow or groove, a provision which allows of
a very great extension of the epidermis.
8
Plate XXIV.
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60 EXPLANATION OF THE P L. A T E S ,
PLATE XXV.
STRUCTURE OF NAILS.
Fig. 1. A longitudinal section of the nail of the middle finger, magni-
fied 130 diameters, showing the direction of the striae or
laminae of cells of which the nail is composed, and which
usually pass from above downwards and forwards. In the
section shown in the figure, the obliquity of the striae is but
slight; the under surface of the nail is distinguished from
the upper by its smooth outline.
Fig. 2. The same, in which the striae are disposed more obliquely,
but in a contrary and unusual direction; viz: from above
downwards and backwards. 130 diameters.
Fig. 3. Other longitudinal sections, in one of which the striae run,
almost vertically. 130 diameters.
Fig. 4. A transverse section of nail, magnified to the same extent as
the former figures ; in it the striae are parallel to the surface,
and are less strongly marked.
Fig. 5. The detached cells of which the super-imposed layers of nails
are composed; the smaller cells are magnified 130 diameters,
the larger 670.
Fig. 4. Plate XXVI. represents the peculiar and beautiful manner in
which the nail and the papillary layer of the true skin are
united.
PlateXXV.
H Miller del ad nat.
E.G.Kelloda.lith
EXPLANATION OF THE PLATES.
01
PLATE XXVI.
STRUCTURE OF EPIDERMIS, ETC.
Fig. 1. A portion of epidermis taken from the back and outer part of
the hand, magnified 100 diameters, and viewed on its upper
surface, showing the elevations by which it is marked, and
which are produced by the papillae of the true skin.
Fig. 2. The same viewed on the under surface, showing the depres-
sions occasioned by the papillae. The number of apertures
of the ducts of the sudoriferous and sebaceous glands is, in
reference to that of the papillae, about one of the former to
six or seven of the latter. 100 diameters.
Fig. 3. A portion of epidermis, magnified 100 diameters, removed from
over the pubis of a woman, and displaying the apertures of
the hair follicles, and the manner in which the hairs issue
from them. Some of the follicles contain but a single hair,
others two or even three: it is probable that this last is the
normal number of hairs enclosed in each follicle wherever
situated, but which in the adult is not generally encountered
in consequence of the continual removal to which hairs are
subject. It is about the apertures of the hair follicles that
the scurf is formed, and concerning which a very erroneous
notion prevails, viz: that it is constituted of desquamated
epidermis. Scurf does not in the least exhibit the structure
of epidermis, but simply consists of the inspissated secretion
of the sebaceous glands, and many of which, opening into
the hair follicles, account for its collection around their
orifices.
Fig. 4. A transverse section of the nail of the middle-toe of an adult,
magnified 100 diameters, showing its lamellated structure,
62 EXPLANATION OF THE PLATES.
and the mode of its connexion with the papillary layer of
the dermis by mutually inter-locking processes. This mode
of union is excessively firm, and is precisely that employed
by carpenters, and known by the appellation of "dovetailing."
Fig. 5. A portion of epidermis removed from the back of the neck by
means of a blister, and magnified 670 diameters. The
younger cells are seen to be filled with a straw-coloured
fluid, the serum extracted through the agency of the vesicant.
Fig. 6. a. Some detached cells of epidermis, obtained by scraping the
sole of the foot, magnified 670 diameters. Cells in a similar
state exist beneath the nails, around the nipple, and on the
surface of the body of new-born children where the creamy
scum formed by them and inter-mingled with fatty matter
poured out by the sebaceous glands has been named Vernix
caseosa. (See c.) — b. Cells of some, magnified 130 diame-
ters.— d. Cells of epithelium from the mouth of the Meno-
branchus lateralis: they are introduced for the purpose of
showing the accuracy of the law of the relation in size of
the several elements entering into the composition of the
animal frame. — e. Two or three epithelial cells of the lateral
ventricles of the brain. I have recently ascertained that
the epithelium of the frontal sinuses is as stated, ciliated. I
cannot help suspecting, however, that it is not in all cases
so. No amount of care has succeeded in the detection of
ciliary epithelium in the ventricles of the brain. The epi-
dermis of tritons and frogs consists of hexagonal, translucent,
and adherent cells, containing distinct granular nuclei.
Plate. XXVI.
w^
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E.C.Kellogg.lith
04 EXPLANATION OF THE PLATES
PLATE XXVII.
PIGMENT CELLS.
Fig. 1. Pigment cells and granules taken from off the inner surface of
the choroid membrane of the human eye, magnified 670
diameters.
Fig. 2. The pigment cells of the inner surface of the choroid of the
eye of the pig, magnified 350 diameters.
Fig. 3, Displays the linear and branched disposition of the stelliform
pigment cells of the lamina fusca of the eye of the pig- A
similar disposition of these cells also exists in the human eye,
but in light-coloured eyes is not strongly marked: the
branches commence on the posterior part of the lamina,
miscalled fusca, since in some instances it is jetty black,
are at first thick and closely arranged; as they approach
the anterior part of the eye, however, they diminish in size,
and are separated by distinct intervals. This figure is
magnified 100 diameters.
Fig. 4. a. Human stelliform pigment cells of the eye, magnified 350
diameters, b. Pigment cells of the skin of the negro,
enlarged 670 diameters, c. Pigment cells from the lungs,
magnified to the same extent.
Fig. 5. A portion of the epidermis of the negro, magnified 350 diame-
ters, and, viewed on its under surface, the pigment cells are
seen to be collected principally in the furrows which exist
between the papillae, the depressions produced by which are
also represented in the figure,
Fig. 6. A portion of the epidermis removed from the areola around
the nipple of a woman recently delivered, and also viewed
upon its under surface. It is seen to differ solely from the
epidermis of the negro in the smaller number of pigment
cells contained in it. 350 diameters.
Obs. Pigment cells and granules frequently exist in the fibres of
the external surface of the sclerotic of some animals, as the pig; and
it is probable that in some instances they may be found in those of
the eye of man.
Hate, XXVII,
■
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.
sp .
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S.Miller.flsladnat.
* ~"<<~ ,.£3 Qp« .-■•"
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L
E C.Kelogg.liiih..
66 EXPLANATION OF THE PLATES.
PLATE XXVIII.
STRUCTURE OF HAIR.
Fig. 1, Shows the structure and depth of implantation of the entire
root of a hair of the scalp, magnified 130 diameters: it dis-
plays the two sheaths which include the stem, and its dilated
extremity, the bulb, and which is seen to rest upon a distinct
cellular vesicle; the outer sheath completely surrounds the
base of the hair, and cuts it off from all direct vascular sup-
ply; the vessels, however, which nourish the hair are seen
to ramify on the external surface of this sheath, which is
also observed to be surrounded by fat vesicles, the r§ot hav-
ing passed through the thickness of the skin, and imbedded
itself in the sub-cutaneous and fatty cellular tissue.
Fig. 2. The root of a gray hair forcibly removed from the scalp ; in
this the outer sheath is seen to be broken off just above the
place at which the stem begins to dilate into the bulb; a
similar rupture almost invariably occurs in the outer sheath
of all hairs, whether coloured or uncoloured, which are
forcibly uprooted. The contrast between the coloured and
the uncoloured hair is striking. 130 diameters.
Fig. 3. The cells of which the outer sheath is composed, magnified
670 diameters.
Fig. 4. A portion of the inner sheath, seen on its inner surface, and
magnified 350 diameters; this is lined with a layer of elon-
gated and nucleated cells; the outer portion of this sheath is
distinctly fibrous, the fibres being formed out of the cells, the
nuclei of which become absorbed: the inner surface also
exhibits transverse markings, the impressions of the scales
of the stem of the hair.
Fig. 5. Some of the pigment cells, of a multitude of which the bulb
of the hair is composed : magnified 670 diameters.
Tlate, XXVIII. .
■
v .
i
«*
H.MilLer, deladnat.
E.C.Kellogt.Mi.
68 EXPLANATION OF THE PLATES.
PLATE XXIX,
STRUCTURE OP HAIR.
Fig. 1. A portion of the stem of a gray hair of the scalp, magnified
350 diameters, showing the medullary canal, the fibres of
the stem, and the outer imbricated scales.
Figs. 2, 3. Transverse sections of hairs of the beard: magnified 130
diameters.
Fig. 4. The fibres of the stem of a hair, magnified 670 diameters.
It is most probable that these fibres originate in the same
way as those of the inner sheath, viz: in nucleated cells.
Figs. 5, 6, 7. Apices of hairs: figs. 6 and 7 represent the points of
two hairs of the scalp, magnified 350 diameters; and fig. 5
that of one of the perineeum. All hairs taken from this
region, as well as those of the axilla, present similar obtuse
extremities, which probably result from the constant friction
to which they are subject in those situations.
Figs. 8, 9, represent the roots of two hairs of the scalp, removed with
the comb; the sheaths, vesicle, and lower portion of the
bulb having remained behind. All hairs removed with the
comb and brush present the same appearances, that of fig.
8 being by far the most common form: magnified 130
diameters.
Fig. 10. A hair from the whisker, magnified 130 diameters, and con-
taining two medullary canals.
Route, XXIX.
7 I 6 1
ff F
10
H.Miller, deladnat.
E.C.Xeflogg.lith.
70 EXPLANATION OF THE PLATES.
PLATE XXX.
STEUCTI7EE OF CAETIIAGE.
Fig.l. A transverse section of the cartilage of a rib, magnified 350
diameters, showing the perichondrium and the compressed
cells of the margin of the cartilage. It is most probable
that it is in the space between the perichondrium and the
external surface of the rib that the chief development of
new cells takes place.
Fig. 2. A transverse section of the same, showing the parent cells,
which are situated more deeply in the cartilage of the rib.
350 diameters.
Fig. 3. A vertical section of the articular cartilage of the head of the
first phalanx of the second finger, including also a portion of
the bone, the cancelli of which contain numerous bone cells,
and the spaces between which are filled with fat vesicles:
magnified 130 diameters.
Fig. 4. A vertical section of the outer part of an inter- vertebral car-
tilage, including a portion of the bone. But few corpuscles,
and these for the most part calcified, occur in the outer part
of these cartilages: the medullary cells of the bone are seen
to be filled with fat vesicles, granular nucleated cells, and
effused blood corpuscles. It sometimes happens that a layer
of true articular cartilage is formed on the surface of the
bone, and then the fibres of the fibro-cartilage take their
origin from it, and not from the bone itself: 80 diameters.
Plate, XXX
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E. Miller, del ad nat.
E.C Kellogg. lith
72 EXPLANATION OF THE PLATES.
PLATE XXXI.
STRUCTURE OF CARTILAGE.
Fig. 1. A thin transverse section of the cartilage of the concha of
the ear: magnified 350 diameters.
Fig. 2. The cells of the centre of an inter-vertebral cartilage in the
different stages of their development. 350 diameters.
Fig. 3. A longitudinal section of the cartilage and bone of the rib of
an adult, showing the mode of union between the two:
magnified 130 diameters.
Fig. 4. A transverse section of one of the rings of the trachea; in
these the cells are so closely aggregated that but little room
is left between them for inter-cellular substance: 350
diameters.
Fig. 5. A transverse section of the thyroid cartilage of a young man,
eighteen years of age, in which fibres analogous to those
of the fibro-cartilages have made their appearance: 130
diameters.
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74 EXPLANATION OF THE PLATES,
PLATE XXXII
STRUCTURE OF BONE.
Fig. 1. A transverse section of ulna, magnified 60 diameters, showing
the Haversian canals, the difference in the size of those sit-
uated on the outer and inner portions of the section, the
systems of the lamellae by which each canal is surrounded,
and the bone cells placed between the lamellae.
Fig. 2. Cross-section of Haversian canals, magnified 220 diameters,
showing the lamellae, and the bone cells with their anasta-
mosing canaliculi more distinctly.
Fig. 3. The same, still more highly magnified, viz: 670 diameters.
Fig. 4. Longitudinal section of long bone, magnified about 40 diame-
ters, showing the Haversian canals, seen lengthways, the
direction of the lamellae and the bone cells.
10
P//U.c XXXII.
H. Miller del.adnat.
l; C Kellodg, lirti.
76- EXPLANATION OF THE PLATES.
PLATE XXXIII.
STRUCTURE AND DEVELOPMENT OF BONE.
Fig. 1. Parietal bone of human fetus, aged about two months, mag-
nified 30 diameters.
Fig. 2. A portion of the same, magnified 60 diameters, showing the
bone cells in process of development, some of which are
seen lying loose in the spaces between the spicula, and
which were destined, eventually, to become included in the
ossific deposition.
Fig. 3. Spicula of bone of a foetal humerus, showing the gradual
deposition of the bony matter in the meshes of fibrous tissue,
and altogether independently of cartilage, magnified 350
diameters.
Fig. 4. Lamina of a long bone, magnified 500 diameters, drawn from
a preparation kindly placed at the author's disposal by Dr.
Sharpey, by whom the structure figured was first described.
Fig. 5. Cancelli of one of the long bones of a human fetus, magnified
350 diameters, showing the vast numbers of granular cor-
puscles which the medullary cells of bone of every age con-
tain, but which are especially abundant in fetal bones; the
larger cells are magnified 750 diameters.
Fig. 6. Cross-section of the femur of a pigeon, fed for twenty-four
hours upon madder. This drawing was made from a beau-
tiful preparation belonging to Mr. Tomes, and lent me by
that gentleman. Magnified 220 diameters.
Ficu&xxxin.
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78 EXPLANATION OF THE PLATE
PLATE XXXIV.
DEVELOPMENT OF BONE.
Fig. 1. Longitudinal section of the epiphysis and a portion of the
shaft of a foetal femur at the ninth month, magnified 100
diameters, and showing the columnar arrangement of the
cartilage cells, together with the increased size of the lower
cells, and the invading spicula of the newly-formed bone.
Fig. 2. Transverse section of primary cancelli, magnified 350 diame-
ters, showing the included nuclei of cartilage cells contained
in the medullary cells or spaces.
Fig. 3. Transverse section of primary cancelli, magnified to the same
extent as the last figure, in a more advanced stage of their
formation, many of the first formed cancelli or septa having
been absorbed, as well as the cell wall of the cartilage cor-
puscles themselves.
Fig. 4. Longitudinal section of the epiphysis and a portion of the
shaft of a foetal femur at the ninth month, magnified 350
diameters.
Plate XXXI]
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80 EXPLANATION OF THE PLATES.
PLATE XXXV,
DEVELOPMENT OF BONE.
Fig. 1. A transverse section of the cartilaginous epiphysis of the lower
end of humerus, magnified 30 diameters, showing the aper-
tures of the canals by which it is traversed.
Fig. 2. The same in connexion with the bone : in this figure it will
be observed that there are fewer canals, that these are of
larger calibre, and that the cartilage cells are disposed
around them in a radiate manner in groups. 30 diameters.
Fig. 3. One of the apertures of the canal, more highly magnified, 330
diameters, showing more clearly the arrangement of the cells
around it, the contents of the canal being granular corpuscles
and blood-vessels, as well as the fact that the inter-cellular
spaces nearest to the opening are the last to become con-
verted into bone: in most of the medullary spaces of the
second tier, the granular corpuscles have already made their
appearance, the cartilage cells having been removed by
absorption.
Fig. 4. The blood-vessels of the medullary cells of a young bone near
the epiphysis injected. For the specimen from which this
figure was drawn I am indebted to the kindness of Mr
Quekett, of the Royal College of Surgeons.
Fig. 5. Transverse section of the shaft of a foetal long bone, displaying
the fact that in fetal bones there are no Haversian canals,
such entirely consisting* of medullary cells. 20 diameters.
Fig. 6. Transverse section of the rib of an adult, magnified 130 diam-
eters, passing obliquely through the junction of the cartilage
with the bone : in the upper part of the figure the cancelli
are seen, including the terminal portions of the lowest tier
of cartilage cells.
PlcuteZZXV.
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82 EXPLANATION OF THE PLATES
PLATE XXXVI,
STRUCTURE OF TEETH.
Fig. I. Vertical section of incisor tooth, magnified with a lens only,
and showing the three constituents of which every human
tooth is composed, viz: superiorly, the enamel; inferiorly,
the cementum ; and in the centre, the dentine, traversed in
the midst by the medullary cavity.
Fig. 2. Tubes of the dentine, showing their ordinary mode of termi-
nation in connexion with the cementum, magnified 670
diameters.
Fig. 3. A not unfrequent condition of the tubes of the dentine, show-
ing their repeated division, and their connexion with bone
cells near their termination. 670 diameters.
Fig. 4. Tubes of the dentine near their commencement from the pulp
cavity seen lengthways : one of the tubes may be observed
to divide in a diachotomous manner. 670 diameters.
Oblique section of tubes of the dentine. 670 diameters.
Transverse section of ditto. 670 diameters.
Displays the breaking up of the tubes of the dentine into bone
cells : this occurs principally near the terminations of those
tubes which pass towards the cementum, and not of those
which run towards the enamel : this condition does not pre-
sent itself in every tooth. 670 diameters.
Fig. 8. Tubes of the dentine, midway between their origin and their
termination, dilated into bone cells. 670 diameters. This
figure is taken from a specimen kindly lent me by Mr. Tomes.
11
Fig.
5.
Fig.
6.
Fig.
7.
Plate, XXXVI.
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84 EXPLANATION OF THE PLATES.
PLATE XXXVII.
STRUCTURE OF TEETH.
Fig. 1. Section of cementum, magnified 670 diameters; internally,
but really near the outer margin of the cementum, some
imperfectly developed bone cells may be observed, each
surrounded by a clear space, having some resemblance to a
cell wall; externally, and bordering upon the dentine, a
closely aggregated layer of still more imperfectly formed
bone cells are seen.
Fig. 2. Section of same traversed by tubes, continuations of those of
the dentine. 670 diameters.
Fig. 3. Section of cementum, showing a number of small angular
cells, and which may frequently be observed in that portion
of the cementum which lies near to the dentine. 670
diameters.
Fig. 4. Oblique section of healthy dentine, over the surface of which
a fungus has developed itself. It is no uncommon circum-
stance to meet with sections thus completely invested with
a similar fungus; I have seen several such. 670 diameters.
Fig. 5. Oblique section of dentine, in which numerous bright globules,
having a resemblance to oil globules, are observed to be
present. 350 diameters.
Fig. 6. Section of secondary dentine, and which also contains Haver-
sian canals. This drawing was made from a preparation
belonging to Mr. Tomes. 350 diameters.
Fig. 7. Transverse section of bicuspid tooth, showing the presence
of an Haversian canal in the cementum, magnified with a
lens only. This drawing has also been made from an inter-
esting preparation, the property of Mr Tomes.
2 Plate. XXXV/7.
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EXPLANATION OF THE PLATES,
PLATE XXXIX.
STRUCTURE OF TENDONS, TEETH, AND FIBROUS TISSUE. •
Fig. L Longitudinal section of a tendon, showing the presence in it
of nucleated fibres of elastic tissue ; these are best seen after
the application of acetic acid, but may be clearly recognised
without the employment of that reagent. 670 diameters.
Fig. 2, Transverse section of same, from which it becomes evident
that the fibres are branched. 670 diameters.
Fig. 3. Vertical section of enamel, magnified 220 diameters. The
enamel cells thus lowly magnified give the section a fibrous
appearance.
Fig. 4. A portion of enamel, magnified 670 diameters, and showing
the enamel cells still more clearly.
Fig. 5. Transverse section of enamel, showing the hexagonal form of
the enamel cells. 670 diameters.
Fig. 6. Inelastic fibrous tissue, magnified 670 diameters.
Fig. 7. Mixed fibrous tissue: the threads of the elastic fibrous tissue
may be recognised by their tortuous course and more defined
outline. 670 diameters.
FL(Lt& IXXIX.
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88 EXPLANATION OF THE PLATE
PLATE XL.
STRUCTURE OF FIBROUS TISSUE.
Fig. 1. Example of elastic fibrous tissue in its ordinary form, taken
from the crico-thyroid membrane, and magnified 670
diameters.
Fig. 2. Form of elastic tissue, constituting the elastic coat of many
blood-vessels of medium calibre. 670 diameters.
Fig. 3. This figure illustrates various stages in the development of
blood-vessels. At first, a transparent and tubular membrane
is surrounded by a single coil of elastic tissue; subsequently,
other coils and filaments appear, the filaments principally take
a longitudinal direction on the tubular membrane, but some
also pass circularly around this ; these threads are nucleated,
and belong to the second form of elastic tissue, and which
is elsewhere encountered in the human organization, as in
tendons, the dartos, &c. 350 diameters. In h the threads
are shown separately.
Fig. 4. A peculiar areolar form of mixed fibrous tissue, magnified
130 diameters, and principally encountered in the great
omentum.
Fig. 5. Blood-vessels from the pia mater. All the smaller vessels pre-
sent a similar structure, their coats being formed of nucleated
filaments of elastic tissue. 350 diameters.
I. Miller,. lei.
E'.C.Kellogs.litli.
90 EXPLANATION OF THE PLATES.
PLATE XL I.
STRUCTURE OF MUSCLE.
Fig. 1. A portion of the surface of a striped muscle, magnified about
60 diameters, showing the distribution of the blood-vessels
and fat globules.
Fig. 2. A fragment of unstriped muscle; the fibres, with their nuclei,
in one-half of the figure are less distinct than in the other,
the filaments in the second half having been submitted to
the action of acetic acid. 670 diameters.
Fig. 3. Muscular fibrillee of the heart; previous to the action of acetic
acid, they are observed to be transversely striped; this
reagent, however, obliterates the stripes, and reduces the
fibrillae to the same condition as those of unstriped muscle.
670 diameters.
Fig. 4. A fragment of the muscle of the frog, showing the distribution
of the capillary vessels and nerves ; the tubules of these last
are observed to terminate in ganglion-like bodies situated
between the muscular fibrillee. 350 diameters.
12
Plate XII.
H.Mffler.ael
92 EXPLANATION OF THE PLATE
PLATE XLII.
STRUCTURE OF MUSCLE.
Fig. 1. Muscular fibres and fibrillae of a voluntary muscle; in one of
the fibres the fibrillae have given way, thus allowing the sar-
colemma to become apparent. This figure, as well as most
of the remaining figures on this plate, are all magnified
about 350 diameters.
Fig. 2. Voluntary muscular fibres acted upon by acetic acid, which
brings clearly into view a number of granular nuclei; these
nuclei are contained in the fibrillae, many of which are
unstriped, and two of which are represented in the figure
separately. 350 diameters.
Fig. 3. This figure represents particulars in reference to muscular
contraction; in a, a fibre is shown which has been placed
upon the stretch, the striae in it are observed to be somewhat
distant, b represents the same fibre in a state of normal
and ordinary contraction ; the diameter of the fibre is seen
to be much greater and the striae closer, a 4, the torn extrem-
ity of a fibre immersed in water prior to the total extinction
of its irritability, and which is observed to be very greatly
contracted ; the difference of distance between the striae in
the contracted and uncontracted portions of the fibre is very
remarkable. C d, a fibre which still retained its irritability
immersed in water; this has caused the fibre to curl up, to
become irregular and undulated; the transverse striae have
disappeared, the longitudinal markings at the same time
being more apparent; in e the extremity only of the fibre
has been immersed in water.
Fig. 4. Shows the great variety in the size of the fibres of a muscle,
the form of the extremities of the fibres, and the mode of
union between these and the tendon. 130 diameters.
Fig. 5. Transverse section of muscular fibres and intervening capilla-
ries. 350 diameters.
FlaloXLII.
H.Mffler.ael.
~£i C. Epilogs. lith..
EXPLANATION OF THE PLATES. 93
PLATE XLIII.
Fig. 1. A portion of a voluntary muscle of a foetus about three months
old, magnified 670 diameters, presenting numerous nuclei,
some of which are imbedded in the fibres, and others lie
between them. At this early period the fibres are formed of
but few fibrillee. The small size of these fibres in comparison
with those of the adult, and which are represented in fig. 6,
is worthy of note. 670 diameters.
Fig. 2. Illustrates the development of the inelastic form of fibrous
tissue from nucleated and granular cells. This figure was
also taken from a foetus at about the third month. 670
diameters.
Fig. 3. A portion of dartos, magnified 350 diameters, showing the
different structures which enter into its composition, viz:
the blood-vessels, the bands of elastic fibrous tissue, and
lastly, the bundles of inelastic fibrous tissue.
Fig. 4. A transverse section of a portion of one of the corpora cavern-
osa penis, showing the apertures of the vessels or cells of
which they are principally composed, as well as the walls of
those cells which are formed, not of nucleated elastic tissue,
but of branched and reticular elastic filaments. This figure
is magnified only a few diameters.
Fig. 5. Muscular fibres of voluntary muscle, disposed in a zigzag
manner; this disposition was formerly considered to be nor-
mal, and to be that assumed by the fibres of every muscle
in a state of contraction, a view which is certainly errone-
ous ; it is encountered in a greater or less degree in all fried
and roasted meats. 350 diameters.
Fig. 6. Striped muscular fibres, magnified 670 diameters. It will be
seen from the figure, that the surface of each fibre is raised
94 EXPLANATION OF THE PLATES.
into ridges with a narrow space intervening between each
ridge, and further, that the ridges are marked out into quad-
rangular spaces, each of which corresponds with a division
of the fibrillae themselves. Now, this form of the surface of
a striped fibre is especially interesting, from the fact of its
enabling us to afford a satisfactory explanation of the nature
of the striae themselves. The most recent explanation given
of the formation of the striae of the voluntary muscular fibre,
and which has been generally adopted, is, that it depends
upon the circumstance that the lines on the fibrillae are
placed so as exactly to correspond with each other, and that
thus a number of smaller lines concur to form a larger one,
the stria of the entire fibre. Such an exact arrangement of
the lines on the fibrillae there is little doubt does really exist,
but it is yet insufficient to explain all the characters pre-
sented by the muscular striae. Thus, although the striae are
usually strongly marked and broad, yet they have no certain
characteristics, either as to position or appearance. In what
way then is the muscular stria produced? A careful exam-
ination of a recent muscular fibre, with an object-glass of
the one-eighth of an inch focus, will satisfy the observer
that the muscular stria is not a thing of shape and substance
itself, but a mere shadow, caused by the ridges into which
the surface of the fibre is raised, and which sometimes falls
on one side the ridge, sometimes on the other, and frequently
in the groove which runs between the ridges, according to
the direction of the light, and the focus in which the object
is viewed. Of the correctness of this explanation it does
not appear to me that there can be a shadow of doubt.
See Appendix to vol. i., page 547.
Flat& Mill.
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90 EXPLANATION OF THE PLATES.
PLATE X L I V.
STRUCTURE OP NERVES.
Fig. 1. Tubes of a motor nerve. The space between the two lines
on each margin indicates the thickness of the white sub-
stance of Schwann. The waved tube represents the
appearance presented by the nervous tubules, when sepa-
rated from each other in water. 670 diameters.
Fig. 2. The same in spirit, showing the nucleated threads of which
the neurilemma is made up. 670 diameters.
Fig. 3. The same in acetic acid, which breaks up the semi-fluid con-
tents of the tubes into globules resembling those of oil. 670
diameters.
Fig. 4. Portions of Casserian ganglia, magnified 350 diameters. In
one of the figures, the ganglion corpuscles are naked ; in the
otrnr, they are invested with a nucleated capsule.
Fig. 5. Nerve tubes of the white substance of the cerebellum, mixed
up with the clear cells described in the text as forming a
considerable portion of the white substance of the cerebrum,
cerebellum, spinal marrow, and nerves of special sense. 670
diameters.
Fig. 6. Nerve tubes of the white substance of one of the hemispheres
of the cerebrum, mixed up with the peculiar cells already
referred to. 670 diameters.
Fig. 7. Tubes of the cerebrum in a varicose condition. 670 diameters.
TUte XLJV.
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"98 EXPLANATION OF THE PLATES.
PLATE XLV.
The majority of the figures in the following Plates were made with the assistance
of the Camera Lucida, and the same instrument will be employed in the delineation
of all future figures wherever practicable.
Fig. 1. Filaments of the great sympathetic, magnified 670 diameters.
Fig. 2. Cells of the gray matter of the cerebellum, outer stratum. 670
diameters.
Fig. 3. Ditto, inner stratum. 670 diameters.
Fig. 4. Caudate ganglionary cells from the gray matter of the spinal
cord, medulla oblongata, and cerebellum ; magnified 350
diameters. Those from the first locality are distinguished
from the rest by their larger size; those from the second
situation by their smallness and elongated form, and the cells
from the cerebellum by their intermediate size and flask
shape.
Fig. 5. Caudate ganglionary cells from the locus niger of the crua
cerebelli. 350 diameters.
Fig. 6. Minute caudate cells from the hippocampus major. 350
diameters.
Fig. 7. Ditto, from the locus niger of crus cerebri. 350 diameters.
13
Flate XLV.
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100 EXPLANATION OF THE PLATES,
PLATE XLVI.
Fig. I. Pacinian corpuscles attached to the cutaneous nerves of the
palm of the hand. Natural size. After Todd and Bowman.
Fig. 2. Pacinian corpuscles, magnified 60 diameters.
Fig. 3. A single Pacinian body, more highly magnified, viz: 100
diameters.
Fig. 4. An anomalous Pacinian body from the mesentery of the cat.
After Todd and Bowman.
Fig. 5. Two other anomalous Pacinian bodies from the same animal.
The latter, reduced from Henle and Kolliker.
Fig. 6. Ganglionary cells from the corpus dentatum of the cerebellum.
350 diameters.
FLaizXLVI.
E.C.Kello^lith
102 EXPLANATION OF THE PLATES.
PLATE XLVII.
Fig. 1. The pleural surface of a portion of lung, magnified 30 diam-
eters. This figure conveys an accurate idea of the form
and great abundance of the air cells.
Fig. 2. Pleural surface of a section of lung, showing the distribution
of the vessels of the first of the three orders of sizes mentioned
in the text. 30 diameters.
Fig. 3. Ditto of lung, magnified 100 diameters. The vessels in this
are not injected, but are represented as they appeared in a
section which had become slightly dried.
Plate XLVII.
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104 EXPLANATION OF THE PLATES.
PLATE XLVIII.
Fig. 1. A section of lung from beneath the pleural surface, magni-
fied 100 diameters, injected with tallow.
Fig. 2. Casts or models of the air cells, magnified 350 diameters,
representing the variety in size and form of these cells, as
well as the shape and number of the openings of com-
munication.
Fig. 3. Deep section of lung, injected with size : the majority of the
cells are observed to be filled with the casts tipped with
colouring matter : other cells may also be seen without casts :
these have evidently been cut across, exposing to view the
ciliated epithelium which lines them. 100 diameters.
Plate XLVJir.
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106 EXPLANATION OF THE PLATES.
PLATE XLIX.
Fig. 1. A portion of the pleural surface of the human lung, with the
vessels of the second order injected. Magnified 100
diameters.
Fig. 2. A section of the human lung, showing the natural appearance
and form of the air cells as seen without injection, also
exhibiting numerous particles of the conoidal ciliated epithe-
lium which lines them. 100 diameters.
Fig. 3. Capillaries of the human lung. Magnified 100 diameters.
The drawing was made from a very beautiful preparation
injected by Mr. Quekett.
14
Rate XLIX
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108 EXPLANATION OF THE PLATES.
PLATE L .
Fig. 1. Follicles of the stomach, as they appear when lined with
conoidal epithelium. 100 diameters.
Fig. 2. Ditto of large intestine in a similar condition. 100 diameters.
Fig. 3. Cross-section of stomach tubes, magnified 100 diameters. The
tubes are parcelled out into sets only when about to pierce
the follicles into which they open; and it is rare to get a
good view of them thus disposed in bundles, each of which
corresponds to the base of a follicle.
Fig. 4. Longitudinal view of stomach tubes, magnified 220 diameters,
showing the spheroidal or glandular epithelium with which
they are lined, as well as the dilated extremities in which
they terminate.
Fig. 5. Ditto, magnified 100 diameters.
Fig. 6. Follicles of the large intestine without epithelium, and cut off,
so as to admit the passage of light through them : when not
thus shortened, their apertures appear dark, in consequence
of the non-transmission of the light. 60 diameters.
Fig. 7. Terminations of the follicles of the large intestine. Magnified
60 diameters.
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110 EXPLANATION OF THE PLATES,
PLATE LI.
Fig. 1. Blood-vessels of the follicles of the appendix vermiformis
injected. Magnified 100 diameters.
Fig. 2. Blood-vessels of the follicles of the stomach of a cat, beautifully
injected. The drawing was made from a preparation of
Dr. Handfield Jones. 100 diameters.
Fig. 3. Villi of the upper part of the small intestine, magnified 60
diameters. Drawing made from a preparation of Dr. Jones.
Fig. 4. Ditto, from the lower portion of the same. 60 diameters.
Fig. 5. Ditto of the foal, injected white and red, the arteries being
red and the veins white. Magnified 60 diameters. Draw-
ing made from a preparation presented by Professor Hyrtle,
of Prague, to the London Microscopical Society.
Fig. 6. Solitary glands of the large intestine in a case of cholera in a
child. Magnified with a lens only.
Plate II.
H Miller, del.
E.CKeUogg.hth"
112 EXPLANATION OF THE PLATES,
PLATE L II.
Fig. 1. Villi, showing the layer of epithelial cells with which they are
generally covered, especially during the intervals of digestion.
Magnified 100 diameters.
Fig. 2. Ditto, uncovered by the layer of epithelium figured in the
previous drawing, and showing the lacteals, as well as the
granular cells, which the villi always contain, whether in an
active or passive condition. 100 diameters.
Fig. 3. Peyer's glands in the cat. Magnified 20 diameters. The
vessels in the villi, between the glands, are injected; but
those of the glands themselves are not so, and this accounts
for their being uncoloured.
Fig. 4. Vertical section of the mucous membrane of the ileum of the
cat, showing the flask-like form of Peyer's glands. No
essential difference exists between these glands, as they
occur in most of the Mammalia, and in the human subject.
This and the previous drawing were prepared from two very
perfect preparations, kindly lent me by Mr. Quekett. 20
diameters.
Fig. 5. Follicles of Lieburkiihn in the duodenum. Magnified 60
diameters.
Fig. 6. Solitary glands of the small intestines uninjected, of their
natural size, and as they occurred in a case of muco-enterite
Plate LIT.
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114 EXPLANATION OF THE PLATES,
PLATE LI'I-I.
Fig. 1. A sebaceous gland from the caruncula lachrymalis in the
human subject; the follicles, on closer examination, I find
to be provided with minute hairs, similar to those which are
present in the sheep and some other animals.
Fig. 2. An entire Meibomian gland. 27 diameters.
Fig. 3. Sebaceous glands in connexion with a hair of the scalp.
These glands are easily procured still attached to the hair
follicle, provided the portion of integument from which they
are to be obtained be permitted to undergo a slight degree
of decomposition. 33 diameters.
Fig. 4. Illustrations of mucous glands. The centre figure represents
a portion of a gland and several of the apertures by which
the follicles in the larger mucous glands communicate with
each other. 45 diameters.
15
Plate LIII.
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116 EXPLANATION OF THE PLATES
PLATE LIV.
Fig. 1. A portion of the parotid gland of an embryo of the sheep, four
inches long, showing it in the very earliest condition of its
development in which it can be traced ; the follicles, although
arranged in clusters, are yet separate and independent of
each other. After Muller. Magnified 8 diameters.
Fig. 2. Shows a further development of the parotid gland in the
human subject ; in this figure the follicles are closely aggre-
gated in clusters, each cluster representing a miniature
lobule. 40 diameters.
Fig. 3. A portion of mammary gland filled with milk globules. 90
diameters.
Fig. 4. A section of liver, showing the form of the lobules and the
arrangement of the secreting cells. The light spaces in the
centre of the lobules indicate the position of the central
hepatic veins. 35 diameters.
Fig. 5. A portion of mammary gland, but slightly magnified.
Fig. 6. Ditto, more highly magnified, showing clearly both its small
granular secreting cells and the milk globules. 198 diam-
eters.
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118 EXPLANATION OF THE PLATES
PLATE LV.
Fig. 1. A portion of the surface of the liver, showing the lobules and
the intra-lobular hepatic veins. The injection has filled
only the larger vessels, and has scarcely penetrated to the
capillaries. 15 diameters.
Fig. 2. Section of liver, in which the hepatic venous system has been
very completely injected, and the portal (in yellow) only
slightly so. The communication between the vessels of
different lobules is also well shown. Drawing made from a
preparation of Dr. Handheld Jones. 20 diameters.
Fig. 3. Would appear to be a portion of the portal system ; the injec-
tion was thrown in from the ductus communis choledochus.
. When introduced in this way, this system always becomes
irregularly filled; and the lobules are not circumscribed as
when the injection enters directly by the portal vein. 20
diameters.
Fig. 4. A section of liver, in which the inter-lobular portal vessels
are shown. The injection in this case also fills only the
principal vessels, and has not extended to the capillaries. 24
diameters.
E.C.Keilooo.lith.
120 EXPLANATION OF THE PLATES.
PLATE LVI.
Fig. 1. A portion of the surface of the liver, in which the portal cap-
illary system has been injected. 20 diameters.
Fig. 2. Section of liver, in which both the portal vein and the hepatic
artery have been injected, the red vessels indicating branches
of the hepatic artery. The drawing was made from a very
perfect injection, kindly lent me for the purpose by Mr.
Quekett. 18 diameters.
Fig. 3. A portion of the surface of the liver, in which both the hepatic
and portal venous systems are well shown, each being dis-
tinct. Drawing made from a preparation of Dr. Handfield
Jones. 20 diameters.
Fig. 4. A section of liver, in which both the portal and hepatic
venous systems have been completely injected from the
portal vein. 20 diameters.
PlcLt& LVI.
122 EXPLANATION OF THE PLATES.
PLATE LVII.
Fig. 1. A terminal biliary duct, copied from a drawing of Dr. H.
Jones. 378 diameters.
Fig. 2. Secreting cells of the liver. The group lettered a represents
the cells in the usual condition in which they are met, when
submitted to observation: in b, the cells are gorged with bile,
while in c, they contain numerous fat or oil globules. 378
diameters.
Fig. 3. Concretions or calculi from the prostate gland. 45 diameters.
Fig. 4. a represents an hitherto undescribed form of tubular gland oc-
curring in the region of the human axilla in close connexion
with the large sudoriferous glands which are there met with.
54 diameters. It differs from these last, however, in several
particulars, but principally in the smaller calibre of the tubes,
and the presence (clearly shown by the action of acetic
acid) of innumerable nuclei in the walls of the tubes, and
of which these would appear to be principally constituted.
In b and c, the differences in the size and structure of the
tubes in the two glands are shown, b and c 198 diameters.
Fig. 5. Ceruminous glands. I cannot detect the slightest difference
between these glands and ordinary sudoriferous glands, with
which, it would appear, they must be considered to be iden-
tical. 45 diameters.
16
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124 EXPLANATION OF THE PLATES.
PLATE LVIII.
Fig. 1. Tubes of the kidney, showing their general character, and but
slightly magnified. 99 diameters.
Fig. 2. Cross-section of the elastic frame-work in which both the
secreting tubes and the Malpighian bodies are enclosed. 99
diameters.
Fig. 3. Cross-section of both the elastic frame-work and the secreting
tubes themselves. 99 diameters.
Fig. 4. Oblique section of the veins contained in the tubular part of
the kidney, showing their arrangement in sets. 33 diameters.
Fig. 5. The same vessels seen lengthways. 33 diameters.
Fig. 6. Secreting tubes of the kidney, in different conditions: in one,
the cells are seen to form a regular pavement epithelium ; in
a second, the central canal, along which the urine, secreted
by the Malpighian bodies and cells of the tubes, flows, is
shown; in a third, the cells are irregularly disposed, and this
is generally found to be the case in the tubes of the central
part of the kidney, and when the kidney is not perfectly
fresh; in a fourth, there are no secreting cells, and the
structureless basement membrane of the tubes alone remains.
378 diameters.
Plate, LVIII.
jE .C.Kelloag.lith.
126 EXPLANATION OF THE PLATES,
PLATE LIX.
Fig. 1. Longitudinal section of kidney, showing the corpora Mal-
pighiana. Magnified 40 diameters.
Fig. 2. Uriniferous tubes of a bird {Gallus indicus), showing their
pinnatifid arrangement. Drawing made from a preparation
of Professor Hyrtl, in the possesion of the Microscopical
Society of London. 40 diameters.
Fig. 3. Corpora Malpighiana of the horse. Drawing made from an
injected preparation by Professor Hyrtl. 40 diameters.
Fig. 4. Vessels of the surface of the kidney. The capillaries are situ-
ated in the interstices between the tubes. 90 diameters.
Fig. 5. A transverse section of the kidney, more highly magnified,
showing the convoluted vessels of the corpora Malpighiana,
as well as the capillaries which encircle the uriniferous tubes.
67 diameters.
lictte LIX
E.C-Kellogi.liti.
128 EXPLANATION OF THE PLATES,
PLATE LX.
Fig. 1. Tubes of the testis, slightly magnified, showing their general
appearance and arrangement.
Fig. 2. Uninjected corpora Malpighiana. a is enveloped in its own
proper capsule, while in b this has been removed. Magnified
100 diameters. Additional observations have convinced me
that these complicated bodies are invested, in addition to the
thick elastic covering spoken of in the text, with an inner
and much thinner membrane; and that it is this which is to
be regarded as the proper Malpighian capsule. This cover-
ing, I conceive, is conveyed to each Malpighian body by the
afferent artery, from which it is reflected over the Malpighian
dilatation and plexus of vessels ; and it may often be seen as
a distinct structure, partially separated from the other con-
stituents of a Malpighian body. The frame-work of elastic
tissue, which invests on every side the tubes and Malpighian
bodies, is every where continuous by its outer surface, that of
one tube with that of the neighbouring tubes, and that of the
Malpighian body is also continuous with that of the tubes
which surround this Malpighian body. On the other hand,
the proper and thin Malpighian capsule is smooth on its outer
surface, and not connected by this surface with any other
structure, save the afferent and efferent vessels along which
it is continued. This general continuity of the elastic frame-
work is well shown in Plate luWWl.fig. 2.
Fig. 3. A. a Malpighian body, more highly magnified, displaying
innumerable small oval and granular cells. The majority
of these, I am now disposed to think, are contained in the
walls of the vessels constituting the Malpighian plexus. The
figure b is after Bowman, and shows the afferent artery and
the efferent vein of the Malpighian tuft; also, the connexion
of the tube with the Malpighian body itself; c, loose epithelial
cells of the tubes. 125 diameters.
Fig. 4. Tube of the testis, more highly magnified, displaying the
innumerable granular cells which fill the tube, as well as the
structure of the tube itself. 99 diameters.
PLat& IX
130 EXPLANATION OF THE PLATES.
PLATE LXI.
Fig. 1. Vessels of thyroid gland. 18 diameters.
Fig. 2. Vesicles of slightly enlarged thyroid, viewed with a lens only.
Fig. 3. Ditto of same, magnified 40 diameters.
Fig. 4. Ditto of same, magnified 67 diameters, showing the fibrous
structure of their walls, and their cellular and nuclear
contents.
Fig. 5. Lobes and vesicles of thyroid, magnified 27 diameters, as seen
in a gland in its ordinary condition.
Fig. 6. Granular nuclei of vesicles of thyroid. Magnified 378
diameters.
Fig. 7. Two follicles of thymus gland, magnified 33 diameters, show-
ing the plexus of vessels which invests them.
Fig. 8. A portion of the capsule of thymus, magnified 54 diameters,
showing the ternary disposition of the vessels.
Fig. 9. Granular nuclei and simple cells with fibrous tissue of thymus.
Magnified 378 diameters.
Fig. 10. Compound cells of thymus. Magnified 378 diameters.
17
Plate, ZZT.
H MQIer el
E-C.Xelic;; litb
132 EXPLANATION OF THE PLATES
PLATE LXII.
Fig. 1. Granular nuclei, blood-vessels, and fibro-elastic tissue of spleen.
Magnified 378 diameters.
Fig. 2. Plexus of vessels on the surface of supra-renal capsule. Mag-
nified 54 diameters.
Fig. 3. a. Tubes of supra-renal capsule. 90 diameters, b. Nuclei,
parent cells, and molecules of the same. 378 diameters.
Fig. 4. Vessels of the foetal portion of the placenta. Magnified 54
diameters. These are seen to terminate in the villi in loops.
Fig. 5. Ditto of the supra-renal capsule, showing the plexus on the
surface of the organ, the long inter- tubular vessels, and the
central plexus. 90 diameters.
Male LX1I.
E C Kellogg, lith
134 EXPLANATION OF THE PLATES.
PLATE LXIII.
Fig. 1. Epidermis of palm of hand, magnified 40 diameters, showing
its disposition in ridges, and the apertures of the sudoriferous
glands.
Fig. 2. Epidermis of the back of the hand, magnified to the same
extent, showing its furrows, hairs, and apertures of sudorif-
erous ducts.
Fig. 3. Papillae of palm of hand. Magnified 54 diameters.
Fig. 4. Ditto of back of hand. Magnified to the same extent.
Fig. 5. Epidermis of palm of hand, seen upon its under surface,
showing pits or depressions for the reception of the papillae,
and the ducts of the sudoriferous glands. Magnified 54
diameters.
Fig. 6. Epidermis of the back of hand, viewed upon its under surface
as a transparent object, and showing depressions for the
papillae and the ducts of the sudoriferous glands. Magnified
54 diameters.
Fig. 7. Blood-vessels of the papillae of the palm of the hand, a single
loop corresponds to each papilla. Magnified 54 diameters.
8. Ditto of the back of the hand. Magnified 54 diameters
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136 EXPLANATION OF THE PLATES,
PLATE LXIV.
Fig. 1. Filiform papillse of the tongue near its centre, with epithelial
appendages attached. Magnified 41 diameters.
Fig. 2. Ditto of same near its apex, with epithelial appendages
attached; these are seen to be much shorter than in the
previous case. Magnified 27 diameters.
Fig. 3. Ditto near the apex of the tongue, with the epithelium removed,
showing their cupped form, and the arrangement and number
of the secondary papillae around their edges. Magnified 27
diameters.
Fig. 4. Ditto near the centre of the tongue, in which situation the
secondary papillae are seen to be much longer and more
slender than in the previous figure, their apices falling
together, and so obscuring the excavation in the centre of
each filiform papilla. Magnified 31 diameters.
Fig. 5. Filiform and fungiform papillae of the tongue, deprived of their
epithelium. The size, form, and structure of the fungiform
papillae are well shown, as well as the simple papillae situated
in the fossa around the base of one of the fungiform papillae.
Magnified 27 diameters.
Fig. 6. Filiform papillae ; some deprived of their epithelial processes,
others still retaining them. In the centre of the figure, two
filiform papillae may be seen occupying the position of a
fungiform papilla, being situated in a fossa studded with
simple papillae. 27 diameters.
Fig. 7. The centre of this figure represents a peculiar form of com-
pound papillae, occupying the position of a fungiform papilla,
but intermediate in structure between it and a filiform papilla.
27 diameters.
Fig. 8. Filiform papillae, showing their tubular form, with the epithe-
lial processes partially removed, and exhibiting numerous
simple papillae placed between the compound ones. 27
diameters.
?I.o.te LXIV.
Miller, ild
eliofie.lith..
138 EXPLANATION OF THE PLATES.
PLATE LXV.
Fig. 1. Mucous follicles of tongue, from under surface, clothed with
their epithelium. Magnified 27 diameters.
Fig. 2. Ditto, with the epithelium removed, viewed as transparent
objects. Magnified 27 diameters.
Fig. 3. Ditto, with the epithelium removed, viewed as opaque objects.
27 diameters.
Fig. 4. Filiform papillae, still invested with epithelium, from the apex
of the tongue near the tip. In this situation the filiform
processes are almost entirely absent, and the cupped form
of the papillae is well seen. 27 diameters.
Fig. 5. Mucous follicles and compound papillae, still invested with
epithelium, from the side of the tongue. Magnified 20
diameters. These compound papillae approach the fungiform
in structure.
Fig. 6. A side view of two simple papillae of the tongue partially
invested with epithelium. 45 diameters.
Fig. 7. Ditto of filiform papillae, with epithelium and epithelial pro-
cesses still adherent. 18 diameters.
Fig. 8. The same, viewed with a lens only.
Fig. 9. Side view of compound papillae situated at the sides of the
tongue posteriorly to the calyciform papillae: the simple
papillae of which they are made up are dilated at the extrem-
ities. 20 diameters.
Fig. 10. Simple papillae from the under surface of the tongue. Mag-
nified 54 diameters.
Fig. 11. Compound and simple papillae from the side of the tongue,
but posteriorly to the calyciform papillae. Magnified 23
diameters.
18
' ite ZXV.
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140 EXPLANATION OF THE PLATES.
PLATE LXVI.
Fig. 1. A single calyciform papilla, with the epithelium removed,
showing the numerous secondary papillae by which it is
covered. 16 diameters.
Fig. 2. Ditto, in a similar state, with the vessels of the papillae injected.
16 diameters.
Fig. 3. Filiform papillae near the centre of the tongue, with the ves-
sels injected. 27 diameters.
Fig. 4. Ditto near the tip of the tongue, also injected. 27 diameters.
Fig. 5. Simple papillae, injected. 27 diameters.
Fig. 6. A fungiform papilla, injected, surrounded by several filiform
papilla, also injected. 27 diameters.
PlaU LXf'l.
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142 EXPLANATION OF THE PLATES.
PLATE LXVII.
Fig. 1. Vertical section of cornea, showing the conjunctival epithe-
lium, the cornea proper, posterior elastic lamina, and epithe-
lium of the aqueous humour. 54 diameters.
Fig. 2. A portion of the vascular layer of the retina, injected. From
a preparation belonging to Mr. Quekett. 60 diameters.
Fig. 3. Section of sclerotic and cornea at the junction of the two
parts. In the sclerotic, the spaces between the fibrous tissue
are seen to be more or less rounded, while in the cornea
they are elongated and tubular. 54 diameters.
Fig. 4. Vessels of tunica Ruyschiana, ciliary processes, iris, and
membrana pupillaris, injected. From a foetal preparation
injected by Mr. Hett. 14 diameters.
Fig. 5. Nuclei of the granular layer of the retina. 378 diameters.
Fig. 6. Cells of the same. 378 diameters.
Fig. 7. Transparent cells of the vesicular layer of the retina. Mag-
nified 378 diameters.
Fig. 8. Caudate cells of the retina. 378 diameters.
Fig. 9. A portion of the membrana Jacobi. 378 diameters.
Fig. 10. Fibres of the crystalline lens, a, magnified 198 diameters;
b, magnified 378 diameters.
Fig. 11. Tuberculated condition of the posterior elastic lamina, as
seen near its margin. 78 diameters.
Fig. 12. Peculiar markings on posterior elastic lamina. Magnified
78 diameters.
Fig. 13. Surface of crystalline lens of the sheep, slightly magnified,
showing the three radii, and the course of the fibres.
Fig. 14. Fibres of the lens near its centre, where they are much
smaller than on the surface. 198 diameters.
rUUeLXVII.
H. Miller del ad.nal
E.CKslloog lith.
144 EXPLANATION OF THE PLATES.
PLATE LXVIII.
Fig. 1. Globe of the eye of the sheep, magnified 3 diameters. The
sclerotic being removed, the choroid is seen, as well as the
disposition of the stellate pigment cells, which lie in the
intervals between the venae vorticosae, and which conse-
quently follow a similar disposition.
Fig. 2. The same, showing the venae vorticosae injected. Magnified
3 diameters.
Fig. 3. Conjunctival epithelium, oblique view of. 378 diameters.
Fig. 4. A portion of the ciliary muscle. 198 diameters.
Fig. 5. Conjunctival epithelium, front view of. 379 diameters.
Fior. 6. Gelatinous nerve fibres of retina. 378 diameters.
Fig. 7. Cellated structure of the vitreous body. 70 diameters.
Fig. 8. Elastic fibres lying on the anterior surface of the posterior
elastic lamina. 70 diameters.
Fig. 9. A portion of iris, showing its blood-vessels and muscular
fibrillse. 70 diameters.
Fig. 10. Epithelium of the crystalline lens. 198 diameters.
Fig. 11. Ditto of the aqueous humour. 198 diameters.
Fig. 12. Cells of the hexagonal epithelium of the choroid. Magnified
378 diameters.
Fig. 13. Cells and fibres of the stellate pigment of the choroid. 378
diameters.
Fie. 14. Irregular pigment cells of the uvea. 378 diameters.
ria^Ljyin.
EXPLANATION OF THE PLATES. 145
PLATE LXIX.
fig. 1. A portion of the mucous membrane of the olfactory region of
the sheep, showing the apertures of the mucous follicles, and
the pigment which covers its surface. 80 diameters.
Fig. 2. Blood-vessels of the pituitary region, injected. From a
preparation belonging to Mr. Quekett. 80 diameters.
Fig. 3. Denticulate lamina of the osseous zone of the lamina spiralis,
seen on the vestibular surface, a, free edge of the teeth ; b,
margin towards the axis of the cochlea; c, granular cells
lying upon the same. 100 diameters.
Fig. 4. Tympanic surface of a portion of lamina spiralis of the cat.
a, termination of the cochlear nerves at the border of the
osseous zone, with capillaries ramifying over them ; b, inner
clear belt of the membranous zone ; c, marginal capillary on
the tympanic surface; d, pectinate portion of the membra-
nous zone ; e, outer clear belt of membranous zone, torn
from the cochlearis muscle. 300 diameters. After Todd
and Bowman.
Fig. 5. Inner view of cochlearis muscle of the sheep, a, line of
attachment of membranous zone of lamina spiralis, of which
a portion, b, remains attached. The surface below this line
is in the scala tympani ; the surface above, the scala vesti-
buli. c, projecting columns, with intervening recesses, iri
the vestibular part of the cochlearis muscle. After Todd
and Bowman.
Fig. 6. Plexiform arrangement of the cochlear nerves, seen in the
basal coil of the lamina spiralis, treated with hydro-chloric
acid. There are no ganglion globules in this plexus, which
consists of tubular fibres, a, twig of cochlear nerve in the
modiolus, its fibres diverging and reuniting in b, a band in
146 EXPLANATION OF THE PLATES.
the plexus taking a direction parallel to the zones. From
this, other twigs radiate, and again and again branch and
unite as far as the margin of the osseous zone, c, where they
terminate. From the sheep. 30 diameters. After Todd
and Bowman.
Fig. 7. Compound cellular and calcareous bodies of the pineal gland.
130 diameters.
Fig. 8. Granular cells and fibrous tissue of the pituitary gland. 350
diameters.
Fig. 9. Villi of the choroid plexus, showing their epithelium and blood-
vessels. 45 diameters.
Figs. 10 and 11. Illustrations of the development of fat. a, repre-
sents the vesicles contained in parent cells ; b, the same after
the absorption of the parent cell membranes. Magnified 45
diameters.
Fig. 12. Dilated capillaries of olfactory region of human foetus. 100
diameters. From a preparation belonging to Mr. Quekett.
19
Plate LXIX.
C.Clutoe.del.
E C KeliodP.lith.
ADDITIONAL PLATES
AMERICAN EDITION,
150 EXPLANATION OF THE PLATES.
PLATES ADDED TO THE AMERICAN EDITION.
PLATE LXX.
Fig. 1. Corpuscles of lymph, showing their granular structure;
although really smaller than the colourless corpuscles of the
blood (Plate I. figs. 1, 2, and 6), they here appear larger in
consequence of being more magnified. 800 diameters.
Fig. 2. Chyle from a mesenteric gland ; the molecular base, with the
granular corpuscles of the same size as those of lymph.
800 diameters.
Fig. 3. Fat vesicles from the arm, injected. The vessels are here
seen to be numerous. As yet, no terminal branches of
nerves or lymphatics have been traced in these vesicles.
Nerves, however, may pass through them to reach other
points. Gurlt has stated that in emaciated subjects the fat
vesiclescontain serum. Todd and Bowman have detected
in emaciated subjects a spontaneous separation of the solid
and fluid principles of the contents of the fat vesicles. 45
diameters.
Fig. 4. Transverse sections of human hair. 450 diameters.
Fig. 5. Cartilage from the finger-joint; it exhibits the manner in
which the vessels on the edge of cartilage form their termi-
nal loopings. 80 diameters.
Fig. 6. Exhibits the contorted and looped vessels of the synovial
membrane. 45 diameters.
/ ! . , e ZXX.
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£.C.ICelloD2.Hth.
152 EXPLANATION OF THE PLATES.
PLATE LXXI.
The vascular surface of the matrix of the nail, surrounded by the
injected papillae of the skin ; the nail and epidermis having been
removed.
a. Papillae of the skin on the dorsal surface of the finger.
b. The lunula : here exist several rows of convoluted capillaries, more
or less complex; these are the horn-vessels of Mr. Rainey.
c. Vessels connecting the lunula with those secreting cuticle. The
office of these vessels, probably, is to secrete a substance inter-
mediate between the horn and the cuticle, and thus cause an
intimate union between them.
d. Folds, or plications of the matrix : these increase in depth as they
approach the end of the finger. They consist of a fold of base-
ment membrane, enclosing a series of loops of vessels. They
are continued into the ridges of the finger, and secrete the cutic-
ular part of the nail.
e. Papillae of the tip of the finger. 8 diameters.
See Appendix, page 463.
Plate LZXI.
IE.
reTice.ileL. ad. iud
Kellogg, lift.
154 EXPLANATION OF THE PLATES,
PLATE LXXII.
Fig. 1. Tendon from the arm. In this figure, the vessels are not
seen to present so uniformly terminal loopings as in the
vessels of cartilage. In many instances, they seem to return
upon themselves. The same termination is sometimes seen
of vessels in cartilage. 60 diameters.
Fig. 2. Tendon from the arm, nearer its muscular union. 30 diameters.
20
Plate ZXXII.
E.C Keilood.Mi.
156 EXPLANATION OF THE PLATES.
PLATE LXXIII.
Fig. 1. Lymphatic vessels and lymphatic glands from the spermatic
cord of the horse, magnified 8 diameters.
AA. The lymphatic glands.
a. a. a. Peripheral, efferent larger lymphatic vessels.
b. b. An efferent or central lymphatic vessel.
c. c. Superficial net- work of delicate lymphatics, which serves in part
to connect the small flat gland, d, with the efferent vessel, b.
d. A very small, loose, semi-glandular plexus of lymphatic vessels.
e. Extensive lymphatic net- work, formed of the vessels of the gland,
and the parts immediately adjacent.
f. Larger lymphatic vessels, passing over and near to the gland, the
numerous valves of which are obvious.
g. Delicate efferent lymphatics. After Gerber.
Figs. 2, 3, and 4, are here introduced to exhibit the relative size of
the air-cells of the lungs at different ages: all equally mag-
nified.
Fig. 2, represents the capillaries and air-cells of a fetal lung. In this,
no air has yet entered, and the air-cells are observed to be
small, and the structure dense. 60 diameters.
Fig. 3, represents capillaries and air-cells of an infant's lung. 60
diameters.
Fig. 4. Capillaries and air-cells of a lung of an adult. 60 diameters.
It is probable that the microscopic examination of the lungs,
in medico-legal questions, as to whether respiration had
taken place, would afford more conclusive evidence than
could be furnished by the usual tests.
Fig. 5. The branchial laminae of the eel. 60 diameters.
Plate LJXHI.
~\'.rB LarvTRiice.
E.C.Keiinog. iitk.
EXPLANATION OF THB PLATES. 157
PLATE LXXIV.
Fig. 1. Injected mucous membrane of fetal stomach. 60 diameters.
From a very perfect injection by Dr. J. Neill.
The honey-comb structure, exhibiting large and polygonal cells,
formed by one or more convoluted capillaries, is here well shown. At
the bottoms of these larger cells, two, three, or more small ones may
be seen. This honey-comb appearance has been considered by many
writers to exist throughout the entire mucous lining of the stomach.
Dr. Jno. Neill has made some valuable investigations on the structure
of this mucous membrane, and his views, founded on the examination
of many injected stomachs, are published in the Am. Journ. of Med.
Sciences, No. XLI. (new series) for Jan. 1851. Figs. 2, 3, and 4 are
taken from that paper.
Dr. Neill considers that after the removal of the epithelium, "the
surface of the mucous membrane presents different appearances in
different portions of the stomach; this fact not having been sufficiently
appreciated by observers, we consider as one of the sources of error
in the ordinary descriptions of this organ. By far the larger portion
exhibits various modifications of the honey-comb structure, the cells
are large and polygonal in some parts; in others, they are smaller,
deeper, and rounder ; the ridges between these cells are formed of one
or more convoluted capillaries, and this arrangement of capillaries is
particularly evident in the rugae (see Jig. 2). The walls of these cells,
or pockets, are formed of a net-work of capillaries, which sub-divides
each cell into smaller ones ; these cells are what are ordinarily called
the orifices of gastric glands, and the sub-division in the bottom of
each cell corresponds with the described orifices of tubuli. In the
antrum pylori, the structure is modified, the ridges between the cells
become larger, more elevated (see Jig. 3), and as we approach the
158 EXPLANATION OF THE PLATES.
pyloric orifice, conical villi make their appearance; these villi are
larger and more numerous towards the pyloric valve, so that fewer of
the angular or polygonal cells are visible in their interstices; they are
not so large as the villi of the small intestine, but in other respects
their external appearances are precisely similar (see fig. 4). When
well injected, they seem to be composed of capillaries, closely united
by a basement membrane, and forming a pyramidal projection.
" There may be said to be three different appearances presented by
the microscopic examination of the injected capillaries of the mucous
membrane of the stomach, when deprived of its epithelium. First,
The convexity of a large ruga will have a comparatively smooth and
even appearance, formed by convoluted and inter-twining capilla-
ries. Second, Any other portion excepting the antrum will exhibit
cells or alveoli of different sizes and shapes, separated by ridges of
various thicknesses, and these ridges are composed of capillaries
arranged in the same manner as in the rugae. Third, in the antrum
pylori, there are conical villi, and cells exist in the interstices and at
their bases."
It will be seen that this description, which the writer has verified
from examination of Dr. Neill's preparations, differs considerably from
those usually given in the various text-books and works treating of
minute anatomy. Dr. Neill is disposed to think that the gastric villi
may be in some way associated with absorption. What precise part
they play in this function, remains yet to be determined.
Fig. 2. Ridges and cells from the left extremity of the fcetal stomach.
After Dr. J. Neill. About 65 diameters.
Fig. 3. Deeper cells and more elevated ridges from the antrum pylori.
After Dr. Neill. About 65 diameters.
Fig. 4. Gastric villi, from the pyloris. After Dr. J. Neill. About
65 diameters.
Fig. 5. The villi of the duodenum injected and the epithelium removed.
The villi in this portion of the small intestine are broad,
fiat, regular and shorter than in the other two divisions.
From an injection by Dr. Neill. 60 diameters.
Fig. 6. Villi from the jejunum: here the villi are longer, not so broad,
and less regularly disposed. 60 diameters.
XY7"V
E .C. Kellogg, lith.
160 EXPLANATION OF THE PLATES,
PLATE LXXV.
Fig. 1. Villi from the ileum. From an injection by Dr. J. Neill. In
this portion of the small intestine, the villi are more conical
than in either of the other divisions, not so flat as in the
duodenum, nor so long as in the jejunum. These different
appearances become more or less modified as we pass from
one division of the intestinal canal to the others. 60 diam-
eters.
Fig. 2. Shows the arrangement of the vessels in the muscular coat
Fig. 3. Mucous membrane of the appendix vermiformis cceci, show-
ing the capillaries and mucous crypts. Dr. J. Neill, in the
Philadelphia Medical Examiner, for February, 1851, has
accurately described the difference of structure between
this appendix and the colon. In the first, the crypts are
variable in size and shape, and the distances between them
by no means uniform. In the colon, the mucous membrane
is regularly studded with mucous crypts or follicles of
Lieberkuhn, all nearly of the same size and shape, and
almost equi-distant. After Neill. About 60 diameters.
Fig. 4. Mucous follicles and capillaries of the colon. After Neill.
About 60 diameters.
Fig. 5. The vascular plexus of the Malpighian body in a healthy state.
The relations of the uriniferous tubes to the Malpighian
bodies are also shown. After Toynbee. About 100 diam-
eters.
Fig. 6. The* vascular plexus of the Malpighian body enlarged, as
occurs in the first stage of Bright's disease: the tubuli are
also seen enlarged. After Toynbee. About 100 diameters.
Fltjjte LXXV.
E:,Pii»iii
^Qu^Mv ^JSjJSI l*'t ill
TfiwYtf-'
i W?ViS^^J
E.C.Kellogg.lith.
162 EXPLANATION OP THE PLATES.
PLATE LXXVI.
Fig. 1. The enlarged veins of the kidney occurring in the first stage
of Bright's disease. After Toynbee.
Fig. 2. Another view of the veins in the same stage : here may be
noticed the commencement of the stellated condition so
characteristic of the more advanced stages of the disease.
After Toynbee.
Fig. 3. The stellated appearance of the veins in the advanced stage
of the disease. After Toynbee.
Fig. 4. Granulation on the surface of the kidney in an advanced
stage of Bright's disease. After Toynbee.
Fig. 5. A urinary tube, very much dilated, in the third stage of the
disease. After Toynbee.
All the above figures are magnified about 100 diameters.
21
1
Place LXXV1
'
(7-,
v.
G\
C-
r- O vv, ^
- i
' r.s-*-A a
EXPLANATION OF THE PLATES. J(J3
PLATE LXXVII.
Fig. 1, represents a magnified view of a vertical section of the skin
under a power of seventy or eighty diameters: g. g. Sudo-
riparous glands imbedded in fat vesicles ; d. the ducts of the
same passing in a flexuous course through the areolar tissue
to de, the dermic portion of the skin ; two of these ducts are
represented cut across. On the right, a duct is represented
cut open at its upper part, and its parietes are seen to be
continuous with the basement membrane of the papillae
which bound it on each side, assuming as it approaches them
an infundibular form. Between the same two papillae may
be seen the lowest portion of the epidermic part of a duct,
at first very indistinctly, and without any defined continuity
of structure with the duct below — gradually assuming a
spiral form, and having the scales of which its walls are
composed, arranged parallel with the axis of the passage.
The other ducts are seen dipping down between and behind
the papillae ; at n, may be seen the nuclei on the basement
membrane of the papillae, which at nc are developed into a
layer of nucleated cells, forming the lower stratum of the
epidermis, ep, through which one complete sudoriferous pas-
sage, p, may be seen passing to the surface, together with
portions of others. The spaces between these passages have
been cut away in the preparation, by which the direction
of the scales of the epidermis not in the vicinity of a passage
are seen to be horizontal, but variously inclined where situ-
ated in its vicinity. After Rainey and Ralph.
Fi£. 2, is a magnified view (220 diameters) of the dermic part; d, the
dermic portion of a duct cut open at its upper part, also
164 EXPLANATION OF THE PLATES.
with the basement membrane of the papillae on each side
continuous with it; p, the epidermic portion of the duct
between the papillae, exhibiting a scaly structure almost at
its commencement; n, nuclei on the basement membrane,
at nc, developed into nucleated cells, and forming together
the lower part of the epidermis ; above which, at ep, may be
seen the commencement of the scaly layer of the epidermis ;
three papillae with a vascular loop in each. After Rainey
and Ralph.
Fig. 3. Mucous membrane of the gall-bladder ; from an injection by Dr.
Jno. Neill, of Philadelphia (see page 358). 50 diameters.
Fig. 4. Transverse section of the muscles of the tongue. The fibres
are of the striped variety, but are not here sufficiently mag-
nified to show the lines. 45 diameters.
Plate LXXVII.
p
cP
fz
■ep
- -71*
■:. >• de
.^jzrj:^?^-
.
!\
166 EXPLANATION OF THE PLATE
PLATE LXXVIII.
Fig. 1. The terminal loopings of vessels in the cornea of the eye of a
pig. 45 diameters.
Fig. 2. The conjunctival epithelium of the cornea in the eye of the
viper, showing its vascularity. In animals that cast their
skin, this lamina is shed with the cuticle of the body. In
the human eye, this lamina is not vascular. 45 diameters.
Fig. 3. Vessels of the choroid coat of the fetal eye, near the ciliary
processes. 45 diameters.
Fig. 4. Ciliary processes of the human adult eye, showing their form
of origin. From an injection by Dr. Jno. Neill, of Philadel-
phia. 45 diameters.
Fig. 5. Mucous lining of the unimpregnated uterus of the sow. 35
diameters.
Fig. 6. Mucous lining of the impregnated uterus of the same animal,
showing how the rugse become developed during gestation.
35 diameters.
Plwte LXXVJ7I
HA J. Id.
"W.H.L.ael
C Kellofiq lift
168 EXPLANATION OF THE PLATES,
PLATE LXXIX.
Fig. 1. A tuft from the fetal portion of the human placenta. 45
diameters.
Fig. 2. Papillae of the gum: a portion of the tooth is represented to
exhibit the manner in which the papillae surround it. From
an injection by Dr. Neill. 45 diameters.
Fig. 3. Papillae from the lip: these are observed to be rather longer
and more prominent than in the gum. From an injection
by Dr. Neill. 45 diameters.
Fig. 4. The arrangement of blood-vessels in the mucous membrane
of the trachea. 45 diameters.
Fig. 5, shows the vascularity of the buccal membrane. 60 diameters
Fig. 6, shows the vascularity of the mucous membrane of the bladder
60 diameters.
, Plate ZXXIX.
H.A.D rlel
.v r. uawr.Ti.ct- it*i
E C.Kallose.Mi
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